Imported Upstream version 1.2~rc2upstream/1.2_rc2

author: Ondřej Surý <ondrej@sury.org> 2013-02-18 12:38:51 +0100
committer: Ondřej Surý <ondrej@sury.org> 2013-02-18 12:38:51 +0100
commit: 2729227efaac366293e70770b6e82e7e775a2605 (patch)
tree: c93797ba617a3e0b0e6fcee14cc0ea5a13b37fcc
parent: 818bb653bebc90f28ea74a14eb1972fbcd172972 (diff)
download: knot-2729227efaac366293e70770b6e82e7e775a2605.tar.gz
99 files changed, 9084 insertions, 3817 deletions
diff --git a/AUTHORS b/AUTHORS
index c032e47..82bb742 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -1,5 +1,6 @@
 Ľuboš Slovák <lubos.slovak@nic.cz>
 Marek Vavruša <marek.vavrusa@nic.cz>
 Jan Kadlec <jan.kadlec@nic.cz>
+Daniel Salzman <daniel.salzman@nic.cz>
 Ondřej Surý <ondrej.sury@nic.cz>
 Ondřej Filip <ondrej.filip@nic.cz>
diff --git a/CodingStyle b/CodingStyle
index 986417c..13dc272 100644
--- a/CodingStyle
+++ b/CodingStyle
@@ -5,7 +5,7 @@ Coding style
 * Max line width: 80 chars
 * Pointer asterisk attached to the name of the variable
 * Own structures/types: _t suffix (f.e. nameserver_t)
-* Header guard format: _KNOTD__HEADER_H_
+* Header guard format: _KNOTD_HEADER_H_
 * Spaces around binary operators
 * Space between keyword and bracket (f.e. "if (predicate)")
 * No space between variable and typecast (f.e. "return (int)val;")
diff --git a/KNOWN_ISSUES b/KNOWN_ISSUES
index fff55a8..4db58a7 100644
--- a/KNOWN_ISSUES
+++ b/KNOWN_ISSUES
@@ -5,7 +5,10 @@ Here is a list of the most notable features that are not supported in the
 current version of Knot.
 
 * Other DNS classes than IN (CH, CS, HS)
-* Dynamic updates
+* Dynamic updates with signed zones have following limitations:
+  - Knot DNS doesn't automatically sign incoming RRs
+  - Removing of RRSIG without covered type specification
+  - Deleting a last RR also removes its RRSIG
 
 Known bugs
 ==========
diff --git a/Knot.files b/Knot.files
index 903cf79..37dc52a 100644
--- a/Knot.files
+++ b/Knot.files
@@ -134,6 +134,8 @@ src/knot/main.c
 src/knot/ctl/knotc_main.c
 src/knot/ctl/process.c
 src/knot/ctl/process.h
+src/knot/ctl/remote.c
+src/knot/ctl/remote.h
 src/knot/other/debug.h
 src/knot/stat/gatherer.c
 src/knot/stat/gatherer.h
diff --git a/RELNOTES b/RELNOTES
index 3a9a1cc..449a849 100644
--- a/RELNOTES
+++ b/RELNOTES
@@ -1,13 +1,31 @@
+v1.2-rc2 - Feb 15, 2013
+-------------------
+
+Bugfixes:
+	* Fixed processing of some non-standard dnames.
+	* Correct checking of label length bounds in some cases. 
+	* More compliant rcodes in case of DDNS/TSIG failures.
+	* Correct processing of malformed DDNS prereq section.
+
+v1.2-rc1 - Jan 4, 2013
+------------------
+
+Features:
+        * Dynamic updates, including forwarding (limited on signed zones)
+        * Updated remote control utility
+        * Configurable TCP timeouts
+        * LOC RR support
+
 v1.1.3 - Dec 19, 2012
 ---------------------
 
-Bugfixes
+Bugfixes:
         * Updated manpage.
 
 v1.1.3-rc1 - Dec 6, 2012
 ------------------------
 
-Bugfixes
+Bugfixes:
 	* Fixed answering DS queries (RRSIGs not together with DS, AA bit 
           missing).
 	* Fixed setting ARCOUNT in some error responses with EDNS enabled.
@@ -18,7 +36,7 @@ Bugfixes
 v1.1.2 - Nov 21, 2012
 ---------------------
 
-Bugfixes
+Bugfixes:
 	* Fixed debug message.
 
 
diff --git a/astylerc b/astylerc
new file mode 100644
index 0000000..95703db
--- /dev/null
+++ b/astylerc
@@ -0,0 +1,12 @@
+--style=1tbs
+--indent=tab=8
+--indent-preprocessor
+--pad-oper
+--pad-header
+--unpad-paren
+--add-brackets
+--convert-tabs
+--align-pointer=name
+--mode=c
+--lineend=linux
+
diff --git a/configure b/configure
index 7d6043f..2549253 100755
--- a/configure
+++ b/configure
@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.69 for knot 1.1.3.
+# Generated by GNU Autoconf 2.69 for knot 1.2-rc2.
 #
 # Report bugs to <knot-dns@labs.nic.cz>.
 #
@@ -590,8 +590,8 @@ MAKEFLAGS=
 # Identity of this package.
 PACKAGE_NAME='knot'
 PACKAGE_TARNAME='knot'
-PACKAGE_VERSION='1.1.3'
-PACKAGE_STRING='knot 1.1.3'
+PACKAGE_VERSION='1.2-rc2'
+PACKAGE_STRING='knot 1.2-rc2'
 PACKAGE_BUGREPORT='knot-dns@labs.nic.cz'
 PACKAGE_URL=''
 
@@ -1319,7 +1319,7 @@ if test "$ac_init_help" = "long"; then
   # Omit some internal or obsolete options to make the list less imposing.
   # This message is too long to be a string in the A/UX 3.1 sh.
   cat <<_ACEOF
-\`configure' configures knot 1.1.3 to adapt to many kinds of systems.
+\`configure' configures knot 1.2-rc2 to adapt to many kinds of systems.
 
 Usage: $0 [OPTION]... [VAR=VALUE]...
 
@@ -1389,7 +1389,7 @@ fi
 
 if test -n "$ac_init_help"; then
   case $ac_init_help in
-     short | recursive ) echo "Configuration of knot 1.1.3:";;
+     short | recursive ) echo "Configuration of knot 1.2-rc2:";;
    esac
   cat <<\_ACEOF
 
@@ -1509,7 +1509,7 @@ fi
 test -n "$ac_init_help" && exit $ac_status
 if $ac_init_version; then
   cat <<\_ACEOF
-knot configure 1.1.3
+knot configure 1.2-rc2
 generated by GNU Autoconf 2.69
 
 Copyright (C) 2012 Free Software Foundation, Inc.
@@ -2062,7 +2062,7 @@ cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
 
-It was created by knot $as_me 1.1.3, which was
+It was created by knot $as_me 1.2-rc2, which was
 generated by GNU Autoconf 2.69.  Invocation command line was
 
   $ $0 $@
@@ -2889,7 +2889,7 @@ fi
 
 # Define the identity of the package.
  PACKAGE='knot'
- VERSION='1.1.3'
+ VERSION='1.2-rc2'
 
 
 cat >>confdefs.h <<_ACEOF
@@ -14068,7 +14068,7 @@ fi
 done
 
 
-for ac_header in arpa/inet.h fcntl.h inttypes.h limits.h malloc.h netdb.h netinet/in_systm.h netinet/in.h stdint.h stdlib.h string.h strings.h sys/socket.h sys/time.h cap-ng.h syslog.h unistd.h urcu.h ev.h pthread_np.h
+for ac_header in arpa/inet.h fcntl.h inttypes.h limits.h malloc.h netdb.h netinet/in_systm.h netinet/in.h stdint.h stdlib.h string.h strings.h sys/socket.h sys/time.h sys/select.h sys/wait.h sys/stat.h cap-ng.h syslog.h unistd.h urcu.h ev.h pthread_np.h
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
 ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"
@@ -15342,7 +15342,7 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 # report actual input values of CONFIG_FILES etc. instead of their
 # values after options handling.
 ac_log="
-This file was extended by knot $as_me 1.1.3, which was
+This file was extended by knot $as_me 1.2-rc2, which was
 generated by GNU Autoconf 2.69.  Invocation command line was
 
   CONFIG_FILES    = $CONFIG_FILES
@@ -15408,7 +15408,7 @@ _ACEOF
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 ac_cs_config="`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`"
 ac_cs_version="\\
-knot config.status 1.1.3
+knot config.status 1.2-rc2
 configured by $0, generated by GNU Autoconf 2.69,
   with options \\"\$ac_cs_config\\"
 
diff --git a/configure.ac b/configure.ac
index 260f379..7a723e5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,7 +1,7 @@
 #                                               -*- Autoconf -*-
 
 AC_PREREQ([2.60])
-AC_INIT([knot], [1.1.3], [knot-dns@labs.nic.cz])
+AC_INIT([knot], [1.2-rc2], [knot-dns@labs.nic.cz])
 AM_INIT_AUTOMAKE([gnu -Wall -Werror])
 AC_CONFIG_SRCDIR([src/knot/main.c])
 AC_CONFIG_HEADERS([src/config.h])
@@ -151,7 +151,7 @@ AC_SEARCH_LIBS([adler32], [z])
 
 # Checks for header files.
 AC_HEADER_RESOLV
-AC_CHECK_HEADERS([arpa/inet.h fcntl.h inttypes.h limits.h malloc.h netdb.h netinet/in_systm.h netinet/in.h stdint.h stdlib.h string.h strings.h sys/socket.h sys/time.h cap-ng.h syslog.h unistd.h urcu.h ev.h pthread_np.h])
+AC_CHECK_HEADERS([arpa/inet.h fcntl.h inttypes.h limits.h malloc.h netdb.h netinet/in_systm.h netinet/in.h stdint.h stdlib.h string.h strings.h sys/socket.h sys/time.h sys/select.h sys/wait.h sys/stat.h cap-ng.h syslog.h unistd.h urcu.h ev.h pthread_np.h])
 
 # Checks for typedefs, structures, and compiler characteristics.
 AC_HEADER_STDBOOL
diff --git a/doc/configuration.texi b/doc/configuration.texi
index 8b7a1ef..ae5a4a1 100644
--- a/doc/configuration.texi
+++ b/doc/configuration.texi
@@ -8,6 +8,8 @@ In this chapter we provide suggested configurations and explain the meaning of i
 * Slave configuration::       
 * Master configuration::       
 * Configuring multiple interfaces::       
+* Using DNS UPDATE::
+* Remote control interface::       
 * Enabling zone semantic checks::
 * Creating IXFR differences from zone file changes::
 @end menu
@@ -86,7 +88,9 @@ form you can define a zone by its name and zone file.
 Knot DNS doesn't strictly differ between master and slave zones.
 The only requirement is to have @code{xfr-in} @code{zones} statement set for given zone,
 thus allowing both incoming XFR from that remote and using it as the
-zone master. Note that you need to explicitly allow incoming NOTIFY, otherwise
+zone master. If @code{update-in} is set and zone has a master,
+any accepted DNS UPDATE will be forwarded to master.
+Also note that you need to explicitly allow incoming NOTIFY, otherwise
 the daemon would reject them.
 Also, you can specify paths, relative to the storage directory.
 See @ref{zones} and @ref{storage}.
@@ -95,12 +99,14 @@ If the zone file doesn't exist and @code{xfr-in} is set, it will be bootstrapped
 @example
 remotes @{
   master @{ address 127.0.0.1@@53; @}
+  subnet1 @{ address 192.168.1.0/24; @}
 @}
 zones @{
   example.com @{  
     file "example.com"; # relative to 'storage'
     xfr-in master;      # define 'master' for this zone
     notify-in master;   # also allow NOTIFY from 'master'
+    update-in subnet1;  # accept UPDATE msgs from subnet1 and forward to master
   @}
 @}
 @end example
@@ -148,6 +154,7 @@ zones @{
     file "/var/zones/example.com";
     xfr-out subnet1, subnet2; # allow outgoing transfers
     notify-out slave;
+    update-in subnet1; # only allow DNS UPDATE from subnet1
   @}
 @}
 @end example
@@ -182,6 +189,61 @@ interfaces @{
 @}
 @end example
 
+@node Using DNS UPDATE
+@section Using DNS UPDATE
+
+As noted in examples for master and slave, it is possible to accept DNS UPDATE messages.
+When the zone is configured as a slave and DNS UPDATE messages is accepted, server forwards the
+message to its primary master specified by @code{xfr-in} directive. When it receives 
+the response from primary master, it forwards it back to the originator. This finishes the transaction.
+
+However, if the zone is configured as master (i.e. not having any @code{xfr-in} directive), it accepts
+such an UPDATE and processes it. As of 1.2, there are a few limitations with DNSSEC signed zones described below. Other than that, UPDATE of unsigned zones works as expected without any limitations.
+
+@itemize @bullet
+@item
+Knot DNS doesn't automatically sign incoming RR if the zone is signed.
+As a workaround, it accepts DNSSEC-related records. However, it may prove challenging
+to create such an UPDATE that it correctly adds/replaces signed RRs, so this
+feature should be treated as experimental until correct signing is implemented.
+
+@item
+As for the reason in a previous point, removing RRSIG with no specified rdata makes it impossible
+to determine whether the user meant a RRSIG for an NSEC3 record or other one.
+Since they are stored separately, it is advisable to always specify RRSIG along with at least the types it covers.
+
+@item
+Deleting a last RR also removes its RRSIG.
+
+@end itemize
+
+@node Remote control interface
+@section Remote control interface
+
+It is possible to control Knot DNS remotely. In order to enable remote control,
+you have to define control interface and an appropriate key. Use of key for
+authentication is strongly recommended. The control protocol is not encrypted,
+and susceptible to replay attack in a short timeframe until message digest expires,
+for that reason, it is recommended to enable remote control only on private networks
+or loopback.
+
+@example
+keys @{
+	knotc-key hmac-md5 "Wg==";
+@}
+remotes @{
+	ctl @{ address 127.0.0.1; key knotc-key; @}
+@}
+control @{
+	listen-on @{ address 127.0.0.1; @}
+	allow ctl;
+@} 
+@end example
+
+The @code{allow} keyword accepts an ACL list, similar to @code{xfr-in} or @code{xfr-out},
+see that for syntax reference. The @code{listen-on} has syntax equal to an interface specification,
+but the default port for remote control protocol is @code{5553}.
+
 @node Enabling zone semantic checks
 @section Enabling zone semantic checks
 You can turn on more detailed semantic
diff --git a/doc/reference.texi b/doc/reference.texi
index 9dffd00..f28608d 100644
--- a/doc/reference.texi
+++ b/doc/reference.texi
@@ -8,6 +8,7 @@ This reference describes every configuration option in Knot DNS server.
 * keys::                        
 * interfaces::                  
 * remotes::                     
+* control::
 * zones::                       
 * log::                         
 @end menu
@@ -38,6 +39,9 @@ else.
   [ @code{pidfile} @code{"}@kbd{string}@code{";} ]
   [ @code{workers} @kbd{integer}@code{;} ]
   [ @code{user} @kbd{string}[@code{.}@kbd{string}]@code{;} ]
+  [ @code{max-conn-idle} ( @kbd{integer} | @kbd{integer}(@code{s} | @code{m} | @code{h} | @code{d})@code{;} ) ]
+  [ @code{max-conn-hs} ( @kbd{integer} | @kbd{integer}(@code{s} | @code{m} | @code{h} | @code{d})@code{;} ) ]
+  [ @code{max-conn-reply} ( @kbd{integer} | @kbd{integer}(@code{s} | @code{m} | @code{h} | @code{d})@code{;} ) ]
 @code{@}}
 @end example
 
@@ -52,6 +56,9 @@ else.
 * pidfile::                     
 * workers::                     
 * user::                        
+* max-conn-idle::
+* max-conn-hs::
+* max-conn-reply::
 @end menu
 
 @node identity
@@ -150,6 +157,27 @@ system @{
 @}
 @end example
 
+@node max-conn-idle
+@subsubsection max-conn-idle
+@vindex max-conn-idle
+
+Maximum idle time between requests on a TCP connection.
+This also limits receiving of a single query, each query must be received in this time limit.
+
+@node max-conn-hs
+@subsubsection max-conn-hs
+@vindex max-conn-hs
+
+Maximum time between newly accepted TCP connection and first query.
+This is useful to disconnect inactive connections faster, than connection
+that already made at least 1 meaningful query.
+
+@node max-conn-reply
+@subsubsection max-conn-reply
+@vindex max-conn-reply
+
+Maximum time to wait for a reply to an issued SOA query.
+
 @node system Example
 @subsection system Example
 
@@ -433,6 +461,57 @@ remotes @{
 
 @end example
 
+@node control 
+@section @code{control} Statement
+
+The @code{control} statement specifies on which interface to listen for remote control commands.
+Caution: The control protocol is not encrypted,
+and susceptible to replay attack in a short timeframe until message digest expires,
+for that reason, it is recommended to enable remote control only on private networks
+or loopback.
+
+@menu
+* control Syntax::              
+* control Statement Definition and Grammar::  
+* control Examples::
+@end menu
+
+@node control Syntax
+@subsection Syntax
+
+@example
+@code{control} @code{@{}
+  [ @kbd{listen-on} @code{@{}
+    ( @code{address} @kbd{ip_address}[@@@kbd{port_number}] |
+      @code{@{} @code{address} @kbd{ip_address}@code{;} [ @code{port} @kbd{port_number}@code{;} ] @code{@}} )
+  @code{@}} ]
+  [ @code{allow} @kbd{remote_id} [, @kbd{remote_id}, @dots{} ]@code{;} ]
+@code{@}}
+@end example
+
+@node control Statement Definition and Grammar
+@subsection Statement Definition and Grammar
+
+Control interface @code{listen-on} definition is equal to @code{interface} definition in @ref{interfaces}.
+Default port for control interface is @code{5553}.
+
+@node control Examples
+@subsection Examples
+
+@example
+keys @{
+        knotc-key hmac-md5 "Wg==";
+@}
+remotes @{
+        ctl @{ address 127.0.0.1; key knotc-key; @}
+@}
+control @{
+        listen-on @{ address 127.0.0.1; @}
+        allow ctl;
+@}
+@end example
+
+
 @node zones
 @section @code{zones} Statement
 
@@ -457,6 +536,7 @@ The @code{zones} statement contains definition of zones served by Knot DNS.
     [ @code{xfr-out} @kbd{remote_id} [, @kbd{remote_id}, @dots{} ]@code{;} ]
     [ @code{notify-in} @kbd{remote_id} [, @kbd{remote_id}, @dots{} ]@code{;} ]
     [ @code{notify-out} @kbd{remote_id} [, @kbd{remote_id}, @dots{} ]@code{;} ]
+    [ @code{update-in} @kbd{remote_id} [, @kbd{remote_id}, @dots{} ]@code{;} ]
     [ @kbd{zone_options} ]
   @code{@}}
 @code{@}}
@@ -482,6 +562,7 @@ The @code{zones} statement contains definition of zones served by Knot DNS.
 * xfr-out::                     
 * notify-in::                        
 * notify-out::                     
+* update-in::
 * semantic-checks::                     
 * ixfr-from-differences::
 * disable-any::                     
@@ -533,6 +614,13 @@ Remotes are defined in @code{remotes} section of configuration file (@pxref{remo
 
 @code{notify-out} defines to which remotes will your server send NOTIFYs about this particular zone.
 
+@node update-in
+@subsubsection update-in
+@vindex update-in
+
+In @code{update-in} statement user specifies which remotes will be permitted to perform a DNS UPDATE.
+Remotes are defined in @code{remotes} section of configuration file (@pxref{remotes}).
+
 @node semantic-checks
 @subsubsection semantic-checks
 @vindex semantic-checks 
diff --git a/samples/knot.full.conf b/samples/knot.full.conf
index 3943b21..8b4571e 100644
--- a/samples/knot.full.conf
+++ b/samples/knot.full.conf
@@ -7,8 +7,8 @@
 # This is a comment.
 
 #
-# There are 4 main sections of this config file:
-#   system, zones, interfaces and log
+# There are 5 main sections of this config file:
+#   system, zones, interfaces, control and log
 #
 
 # Section 'system' contains general options for the server
@@ -18,7 +18,7 @@ system {
   identity "I have no mouth and must scream";
 
   # Version of the server (see RFC 4892). Not used yet.
-  version "1.1.0";
+  version "1.2;
 
   # Server identifier 
   # Use string format "text"
@@ -41,6 +41,25 @@ system {
   # User for running server
   # May also specify user.group (e.g. knot.users)
   # user knot.users;
+
+  # Maximum idle time between requests on a TCP connection
+  # It is also possible to suffix with unit size [s/m/h/d]
+  # f.e. 1s = 1 second, 1m = 1 minute, 1h = 1 hour, 1d = 1 day
+  # Default: 60s
+  max-conn-idle 60s;
+
+  # Maximum time between newly accepted TCP connection and first query
+  # This is useful to disconnect inactive connections faster
+  # It is also possible to suffix with unit size [s/m/h/d]
+  # f.e. 1s = 1 second, 1m = 1 minute, 1h = 1 hour, 1d = 1 day
+  # Default: 10s
+  max-conn-handshake 10s;
+
+  # Maximum time to wait for a reply to SOA query
+  # It is also possible to suffix with unit size [s/m/h/d]
+  # f.e. 1s = 1 second, 1m = 1 minute, 1h = 1 hour, 1d = 1 day
+  # Default: 10s
+  max-conn-reply 10s;
 }
 
 # Section 'keys' contains list of TSIG keys
@@ -113,6 +132,21 @@ remotes {
   }
 }
 
+# Section 'control' specifies on which interface to listen for RC commands
+control {
+
+  # Specifies interface, syntax is exactly the same as in 'interfaces' section
+  # Note: as of now, it is possible replay commands in a short time frame
+  #       with MitM type attacks, so you should keep the interface on localnet.
+  # Default port is: 5553
+  listen-on { address 127.0.0.1@5553; }
+  
+  # Specifies ACL list for remote control
+  # Same syntax as for ACLs in zones
+  # List of remotes delimited by comma
+  allow server0;
+}
+
 # Section 'zones' contains information about zones to be served.
 zones {
 
@@ -210,6 +244,9 @@ zones {
 
     # List of servers to send NOTIFY to 
     notify-out server0, server1;
+
+    # List of servers to allow UPDATE queries
+    update-in server0;
   }
 }
 
diff --git a/src/Makefile.am b/src/Makefile.am
index 1bd26f5..4458615 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -56,6 +56,10 @@ knot_zcompile_SOURCES =				\
 unittests_SOURCES =				\
 	tests/common/acl_tests.c		\
 	tests/common/acl_tests.h		\
+	tests/common/base32hex_tests.c		\
+	tests/common/base32hex_tests.h		\
+	tests/common/base64_tests.c		\
+	tests/common/base64_tests.h		\
 	tests/common/events_tests.c		\
 	tests/common/events_tests.h		\
 	tests/common/skiplist_tests.c		\
@@ -219,13 +223,11 @@ libknots_la_SOURCES =				\
 	common/mempattern.h			\
 	common/mempattern.c			\
 	common/lists.c				\
-	common/base32.c				\
 	common/base64.c				\
 	common/base64.h				\
 	common/lists.h				\
 	common/heap.h				\
 	common/heap.c				\
-	common/base32.h				\
 	common/print.c				\
 	common/print.h				\
 	common/skip-list.c			\
@@ -282,6 +284,8 @@ libknotd_la_SOURCES =				\
 	knot/conf/conf.h			\
 	knot/ctl/process.c			\
 	knot/ctl/process.h			\
+	knot/ctl/remote.c			\
+	knot/ctl/remote.h			\
 	knot/server/dthreads.c			\
 	knot/server/journal.c			\
 	knot/server/socket.c				\
diff --git a/src/Makefile.in b/src/Makefile.in
index 4db92fc..7c00c90 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -86,14 +86,14 @@ am_libknot_la_OBJECTS = utils.lo debug.lo descriptor.lo tolower.lo \
 libknot_la_OBJECTS = $(am_libknot_la_OBJECTS)
 libknotd_la_DEPENDENCIES = libknot.la libknots.la @LIBOBJS@
 am_libknotd_la_OBJECTS = gatherer.lo stat.lo libknotd_la-cf-parse.lo \
-	libknotd_la-cf-lex.lo conf.lo logconf.lo process.lo \
+	libknotd_la-cf-lex.lo conf.lo logconf.lo process.lo remote.lo \
 	dthreads.lo journal.lo socket.lo server.lo udp-handler.lo \
 	tcp-handler.lo xfr-handler.lo zones.lo notify.lo zone-load.lo \
 	semantic-check.lo zone-dump.lo zone-dump-text.lo
 libknotd_la_OBJECTS = $(am_libknotd_la_OBJECTS)
 libknots_la_DEPENDENCIES = @LIBOBJS@
 am_libknots_la_OBJECTS = slab.lo tap.lo mempattern.lo lists.lo \
-	base32.lo base64.lo heap.lo print.lo skip-list.lo base32hex.lo \
+	base64.lo heap.lo print.lo skip-list.lo base32hex.lo \
 	general-tree.lo evqueue.lo evsched.lo acl.lo sockaddr.lo \
 	ref.lo errors.lo errcode.lo dSFMT.lo prng.lo fdset.lo \
 	fdset_poll.lo fdset_kqueue.lo fdset_epoll.lo log.lo
@@ -114,7 +114,8 @@ knotc_DEPENDENCIES = libknotd.la libknot.la libknots.la @LIBOBJS@
 am_knotd_OBJECTS = main.$(OBJEXT)
 knotd_OBJECTS = $(am_knotd_OBJECTS)
 knotd_DEPENDENCIES = libknotd.la libknot.la libknots.la @LIBOBJS@
-am_unittests_OBJECTS = acl_tests.$(OBJEXT) events_tests.$(OBJEXT) \
+am_unittests_OBJECTS = acl_tests.$(OBJEXT) base32hex_tests.$(OBJEXT) \
+	base64_tests.$(OBJEXT) events_tests.$(OBJEXT) \
 	skiplist_tests.$(OBJEXT) slab_tests.$(OBJEXT) \
 	fdset_tests.$(OBJEXT) conf_tests.$(OBJEXT) \
 	dthreads_tests.$(OBJEXT) journal_tests.$(OBJEXT) \
@@ -405,6 +406,10 @@ knot_zcompile_SOURCES = \
 unittests_SOURCES = \
 	tests/common/acl_tests.c		\
 	tests/common/acl_tests.h		\
+	tests/common/base32hex_tests.c		\
+	tests/common/base32hex_tests.h		\
+	tests/common/base64_tests.c		\
+	tests/common/base64_tests.h		\
 	tests/common/events_tests.c		\
 	tests/common/events_tests.h		\
 	tests/common/skiplist_tests.c		\
@@ -567,13 +572,11 @@ libknots_la_SOURCES = \
 	common/mempattern.h			\
 	common/mempattern.c			\
 	common/lists.c				\
-	common/base32.c				\
 	common/base64.c				\
 	common/base64.h				\
 	common/lists.h				\
 	common/heap.h				\
 	common/heap.c				\
-	common/base32.h				\
 	common/print.c				\
 	common/print.h				\
 	common/skip-list.c			\
@@ -630,6 +633,8 @@ libknotd_la_SOURCES = \
 	knot/conf/conf.h			\
 	knot/ctl/process.c			\
 	knot/ctl/process.h			\
+	knot/ctl/remote.c			\
+	knot/ctl/remote.h			\
 	knot/server/dthreads.c			\
 	knot/server/journal.c			\
 	knot/server/socket.c				\
@@ -866,9 +871,10 @@ distclean-compile:
 
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/acl.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/acl_tests.Po@am__quote@
-@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/base32.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/base32hex.Plo@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/base32hex_tests.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/base64.Plo@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/base64_tests.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/changesets.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/conf.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/conf_tests.Po@am__quote@
@@ -934,6 +940,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/rdata_tests.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/rdata_tests_realdata.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/ref.Plo@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/remote.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/response.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/response_tests.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/response_tests_realdata.Po@am__quote@
@@ -1238,6 +1245,13 @@ process.lo: knot/ctl/process.c
 @AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
 @am__fastdepCC_FALSE@	$(LIBTOOL)  --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o process.lo `test -f 'knot/ctl/process.c' || echo '$(srcdir)/'`knot/ctl/process.c
 
+remote.lo: knot/ctl/remote.c
+@am__fastdepCC_TRUE@	$(LIBTOOL)  --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT remote.lo -MD -MP -MF $(DEPDIR)/remote.Tpo -c -o remote.lo `test -f 'knot/ctl/remote.c' || echo '$(srcdir)/'`knot/ctl/remote.c
+@am__fastdepCC_TRUE@	$(am__mv) $(DEPDIR)/remote.Tpo $(DEPDIR)/remote.Plo
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	source='knot/ctl/remote.c' object='remote.lo' libtool=yes @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(LIBTOOL)  --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o remote.lo `test -f 'knot/ctl/remote.c' || echo '$(srcdir)/'`knot/ctl/remote.c
+
 dthreads.lo: knot/server/dthreads.c
 @am__fastdepCC_TRUE@	$(LIBTOOL)  --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT dthreads.lo -MD -MP -MF $(DEPDIR)/dthreads.Tpo -c -o dthreads.lo `test -f 'knot/server/dthreads.c' || echo '$(srcdir)/'`knot/server/dthreads.c
 @am__fastdepCC_TRUE@	$(am__mv) $(DEPDIR)/dthreads.Tpo $(DEPDIR)/dthreads.Plo
@@ -1357,13 +1371,6 @@ lists.lo: common/lists.c
 @AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
 @am__fastdepCC_FALSE@	$(LIBTOOL)  --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o lists.lo `test -f 'common/lists.c' || echo '$(srcdir)/'`common/lists.c
 
-base32.lo: common/base32.c
-@am__fastdepCC_TRUE@	$(LIBTOOL)  --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT base32.lo -MD -MP -MF $(DEPDIR)/base32.Tpo -c -o base32.lo `test -f 'common/base32.c' || echo '$(srcdir)/'`common/base32.c
-@am__fastdepCC_TRUE@	$(am__mv) $(DEPDIR)/base32.Tpo $(DEPDIR)/base32.Plo
-@AMDEP_TRUE@@am__fastdepCC_FALSE@	source='common/base32.c' object='base32.lo' libtool=yes @AMDEPBACKSLASH@
-@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
-@am__fastdepCC_FALSE@	$(LIBTOOL)  --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o base32.lo `test -f 'common/base32.c' || echo '$(srcdir)/'`common/base32.c
-
 base64.lo: common/base64.c
 @am__fastdepCC_TRUE@	$(LIBTOOL)  --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT base64.lo -MD -MP -MF $(DEPDIR)/base64.Tpo -c -o base64.lo `test -f 'common/base64.c' || echo '$(srcdir)/'`common/base64.c
 @am__fastdepCC_TRUE@	$(am__mv) $(DEPDIR)/base64.Tpo $(DEPDIR)/base64.Plo
@@ -1616,6 +1623,34 @@ acl_tests.obj: tests/common/acl_tests.c
 @AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
 @am__fastdepCC_FALSE@	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o acl_tests.obj `if test -f 'tests/common/acl_tests.c'; then $(CYGPATH_W) 'tests/common/acl_tests.c'; else $(CYGPATH_W) '$(srcdir)/tests/common/acl_tests.c'; fi`
 
+base32hex_tests.o: tests/common/base32hex_tests.c
+@am__fastdepCC_TRUE@	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT base32hex_tests.o -MD -MP -MF $(DEPDIR)/base32hex_tests.Tpo -c -o base32hex_tests.o `test -f 'tests/common/base32hex_tests.c' || echo '$(srcdir)/'`tests/common/base32hex_tests.c
+@am__fastdepCC_TRUE@	$(am__mv) $(DEPDIR)/base32hex_tests.Tpo $(DEPDIR)/base32hex_tests.Po
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	source='tests/common/base32hex_tests.c' object='base32hex_tests.o' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o base32hex_tests.o `test -f 'tests/common/base32hex_tests.c' || echo '$(srcdir)/'`tests/common/base32hex_tests.c
+
+base32hex_tests.obj: tests/common/base32hex_tests.c
+@am__fastdepCC_TRUE@	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT base32hex_tests.obj -MD -MP -MF $(DEPDIR)/base32hex_tests.Tpo -c -o base32hex_tests.obj `if test -f 'tests/common/base32hex_tests.c'; then $(CYGPATH_W) 'tests/common/base32hex_tests.c'; else $(CYGPATH_W) '$(srcdir)/tests/common/base32hex_tests.c'; fi`
+@am__fastdepCC_TRUE@	$(am__mv) $(DEPDIR)/base32hex_tests.Tpo $(DEPDIR)/base32hex_tests.Po
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	source='tests/common/base32hex_tests.c' object='base32hex_tests.obj' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o base32hex_tests.obj `if test -f 'tests/common/base32hex_tests.c'; then $(CYGPATH_W) 'tests/common/base32hex_tests.c'; else $(CYGPATH_W) '$(srcdir)/tests/common/base32hex_tests.c'; fi`
+
+base64_tests.o: tests/common/base64_tests.c
+@am__fastdepCC_TRUE@	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT base64_tests.o -MD -MP -MF $(DEPDIR)/base64_tests.Tpo -c -o base64_tests.o `test -f 'tests/common/base64_tests.c' || echo '$(srcdir)/'`tests/common/base64_tests.c
+@am__fastdepCC_TRUE@	$(am__mv) $(DEPDIR)/base64_tests.Tpo $(DEPDIR)/base64_tests.Po
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	source='tests/common/base64_tests.c' object='base64_tests.o' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o base64_tests.o `test -f 'tests/common/base64_tests.c' || echo '$(srcdir)/'`tests/common/base64_tests.c
+
+base64_tests.obj: tests/common/base64_tests.c
+@am__fastdepCC_TRUE@	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT base64_tests.obj -MD -MP -MF $(DEPDIR)/base64_tests.Tpo -c -o base64_tests.obj `if test -f 'tests/common/base64_tests.c'; then $(CYGPATH_W) 'tests/common/base64_tests.c'; else $(CYGPATH_W) '$(srcdir)/tests/common/base64_tests.c'; fi`
+@am__fastdepCC_TRUE@	$(am__mv) $(DEPDIR)/base64_tests.Tpo $(DEPDIR)/base64_tests.Po
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	source='tests/common/base64_tests.c' object='base64_tests.obj' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o base64_tests.obj `if test -f 'tests/common/base64_tests.c'; then $(CYGPATH_W) 'tests/common/base64_tests.c'; else $(CYGPATH_W) '$(srcdir)/tests/common/base64_tests.c'; fi`
+
 events_tests.o: tests/common/events_tests.c
 @am__fastdepCC_TRUE@	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT events_tests.o -MD -MP -MF $(DEPDIR)/events_tests.Tpo -c -o events_tests.o `test -f 'tests/common/events_tests.c' || echo '$(srcdir)/'`tests/common/events_tests.c
 @am__fastdepCC_TRUE@	$(am__mv) $(DEPDIR)/events_tests.Tpo $(DEPDIR)/events_tests.Po
diff --git a/src/common/base32.c b/src/common/base32.c
deleted file mode 100644
index 43b86c1..0000000
--- a/src/common/base32.c
+++ /dev/null
@@ -1,539 +0,0 @@
-/* base32.c -- Encode binary data using printable characters.
-   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2006, 2010 Free Software
-   Foundation, Inc.
-
-   This program is free software; you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2, or (at your option)
-   any later version.
-
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
-
-   You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software Foundation,
-   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
-
-/* Adapted from base64.{h,c} by Ondřej Surý.  base64.{h,c} was written
- * by Simon Josefsson.  Partially adapted from GNU MailUtils
- * (mailbox/filter_trans.c, as of 2004-11-28).  Improved by review
- * from Paul Eggert, Bruno Haible, and Stepan Kasal.
- *
- * See also RFC 4648 <http://www.ietf.org/rfc/rfc4648.txt>.
- *
- * Be careful with error checking.  Here is how you would typically
- * use these functions:
- *
- * bool ok = base32_decode_alloc (in, inlen, &out, &outlen);
- * if (!ok)
- *   FAIL: input was not valid base32
- * if (out == NULL)
- *   FAIL: memory allocation error
- * OK: data in OUT/OUTLEN
- *
- * size_t outlen = base32_encode_alloc (in, inlen, &out);
- * if (out == NULL && outlen == 0 && inlen != 0)
- *   FAIL: input too long
- * if (out == NULL)
- *   FAIL: memory allocation error
- * OK: data in OUT/OUTLEN.
- *
- */
-
-/* Get prototype. */
-#include "base32.h"
-
-/* Get malloc. */
-#include <stdlib.h>
-
-/* Get UCHAR_MAX. */
-#include <limits.h>
-
-/* C89 compliant way to cast 'char' to 'unsigned char'. */
-static inline unsigned char to_uchar(char ch)
-{
-	return ch;
-}
-
-/* Base32 encode IN array of size INLEN into OUT array of size OUTLEN.
-   If OUTLEN is less than BASE32_LENGTH(INLEN), write as many bytes as
-   possible.  If OUTLEN is larger than BASE32_LENGTH(INLEN), also zero
-   terminate the output buffer. */
-void base32_encode(const char *in, size_t inlen, char *out, size_t outlen)
-{
-	static const char b32str[32] =
-		"ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
-
-	while (inlen && outlen) {
-		*out++ = b32str[(to_uchar(in[0]) >> 3) & 0x1f];
-		if (!--outlen) {
-			break;
-		}
-		*out++ = b32str[((to_uchar(in[0]) << 2)
-		                + (--inlen ? to_uchar(in[1]) >> 6 : 0))
-		                & 0x1f];
-		if (!--outlen) {
-			break;
-		}
-		*out++ =(inlen
-		         ? b32str[(to_uchar(in[1]) >> 1) & 0x1f]
-		         : '=');
-		if (!--outlen) {
-			break;
-		}
-		*out++ = (inlen
-		         ? b32str[((to_uchar(in[1]) << 4)
-		                   + (--inlen ? to_uchar(in[2]) >> 4 : 0))
-		                   & 0x1f]
-		         : '=');
-		if (!--outlen) {
-			break;
-		}
-		*out++ = (inlen
-		          ? b32str[((to_uchar(in[2]) << 1)
-		                   + (--inlen ? to_uchar(in[3]) >> 7 : 0))
-		                   & 0x1f]
-		          : '=');
-		if (!--outlen) {
-			break;
-		}
-		*out++ = (inlen
-		          ? b32str[(to_uchar(in[3]) >> 2) & 0x1f]
-		          : '=');
-		if (!--outlen)
-		{
-			break;
-		}
-		*out++ = (inlen
-		          ? b32str[((to_uchar(in[3]) << 3)
-		                   + (--inlen ? to_uchar(in[4]) >> 5 : 0))
-		                   & 0x1f]
-		          : '=');
-		if (!--outlen) {
-			break;
-		}
-		*out++ = inlen ? b32str[to_uchar(in[4]) & 0x1f] : '=';
-		if (!--outlen) {
-			break;
-		}
-		if (inlen) {
-			inlen--;
-		}
-		if (inlen) {
-			in += 5;
-		}
-	}
-
-	if (outlen) {
-		*out = '\0';
-	}
-}
-
-/* Allocate a buffer and store zero terminated base32 encoded data
-   from array IN of size INLEN, returning BASE32_LENGTH(INLEN), i.e.,
-   the length of the encoded data, excluding the terminating zero.  On
-   return, the OUT variable will hold a pointer to newly allocated
-   memory that must be deallocated by the caller.  If output string
-   length would overflow, 0 is returned and OUT is set to NULL.  If
-   memory allocation failed, OUT is set to NULL, and the return value
-   indicates length of the requested memory block, i.e.,
-   BASE32_LENGTH(inlen) + 1. */
-size_t base32_encode_alloc(const char *in, size_t inlen, char **out)
-{
-	size_t outlen = 1 + BASE32_LENGTH (inlen);
-
-	/* Check for overflow in outlen computation.
-	 *
-	 * If there is no overflow, outlen >= inlen.
-	 *
-	 * If the operation (inlen + 2) overflows then it yields at most +1, so
-	 * outlen is 0.
-	 *
-	 * If the multiplication overflows, we lose at least half of the
-	 * correct value, so the result is < ((inlen + 2) / 3) * 2, which is
-	 * less than (inlen + 2) * 0.66667, which is less than inlen as soon as
-	 * (inlen > 4).
-	 */
-	if (inlen > outlen)
-	{
-		*out = NULL;
-		return 0;
-	}
-
-	*out = malloc(outlen);
-	if (!*out) {
-		return outlen;
-	}
-
-	base32_encode(in, inlen, *out, outlen);
-
-	return outlen - 1;
-}
-
-/* With this approach this file works independent of the charset used
-   (think EBCDIC).  However, it does assume that the characters in the
-   Base32 alphabet (A-Z2-7) are encoded in 0..255.  POSIX
-   1003.1-2001 require that char and unsigned char are 8-bit
-   quantities, though, taking care of that problem.  But this may be a
-   potential problem on non-POSIX C99 platforms.
-
-   IBM C V6 for AIX mishandles "#define B32(x) ...'x'...", so use "_"
-   as the formal parameter rather than "x".  */
-#define B32(_)					\
-	((_) == 'A' ? 0				\
-	 : (_) == 'B' ? 1			\
-	 : (_) == 'C' ? 2			\
-	 : (_) == 'D' ? 3			\
-	 : (_) == 'E' ? 4			\
-	 : (_) == 'F' ? 5			\
-	 : (_) == 'G' ? 6			\
-	 : (_) == 'H' ? 7			\
-	 : (_) == 'I' ? 8			\
-	 : (_) == 'J' ? 9			\
-	 : (_) == 'K' ? 10			\
-	 : (_) == 'L' ? 11			\
-	 : (_) == 'M' ? 12			\
-	 : (_) == 'N' ? 13			\
-	 : (_) == 'O' ? 14			\
-	 : (_) == 'P' ? 15			\
-	 : (_) == 'Q' ? 16			\
-	 : (_) == 'R' ? 17			\
-	 : (_) == 'S' ? 18			\
-	 : (_) == 'T' ? 19			\
-	 : (_) == 'U' ? 20			\
-	 : (_) == 'V' ? 21			\
-	 : (_) == 'W' ? 22			\
-	 : (_) == 'X' ? 23			\
-	 : (_) == 'Y' ? 24			\
-	 : (_) == 'Z' ? 25			\
-	 : (_) == '2' ? 26			\
-	 : (_) == '3' ? 27			\
-	 : (_) == '4' ? 28			\
-	 : (_) == '5' ? 29			\
-	 : (_) == '6' ? 30			\
-	 : (_) == '7' ? 31			\
-	 : -1)
-
-static const signed char b32[0x100] = {
-	B32 (0), B32 (1), B32 (2), B32 (3),
-	B32 (4), B32 (5), B32 (6), B32 (7),
-	B32 (8), B32 (9), B32 (10), B32 (11),
-	B32 (12), B32 (13), B32 (14), B32 (15),
-	B32 (16), B32 (17), B32 (18), B32 (19),
-	B32 (20), B32 (21), B32 (22), B32 (23),
-	B32 (24), B32 (25), B32 (26), B32 (27),
-	B32 (28), B32 (29), B32 (30), B32 (31),
-	B32 (32), B32 (33), B32 (34), B32 (35),
-	B32 (36), B32 (37), B32 (38), B32 (39),
-	B32 (40), B32 (41), B32 (42), B32 (43),
-	B32 (44), B32 (45), B32 (46), B32 (47),
-	B32 (48), B32 (49), B32 (50), B32 (51),
-	B32 (52), B32 (53), B32 (54), B32 (55),
-	B32 (56), B32 (57), B32 (58), B32 (59),
-	B32 (60), B32 (61), B32 (62), B32 (63),
-	B32 (64), B32 (65), B32 (66), B32 (67),
-	B32 (68), B32 (69), B32 (70), B32 (71),
-	B32 (72), B32 (73), B32 (74), B32 (75),
-	B32 (76), B32 (77), B32 (78), B32 (79),
-	B32 (80), B32 (81), B32 (82), B32 (83),
-	B32 (84), B32 (85), B32 (86), B32 (87),
-	B32 (88), B32 (89), B32 (90), B32 (91),
-	B32 (92), B32 (93), B32 (94), B32 (95),
-	B32 (96), B32 (97), B32 (98), B32 (99),
-	B32 (100), B32 (101), B32 (102), B32 (103),
-	B32 (104), B32 (105), B32 (106), B32 (107),
-	B32 (108), B32 (109), B32 (110), B32 (111),
-	B32 (112), B32 (113), B32 (114), B32 (115),
-	B32 (116), B32 (117), B32 (118), B32 (119),
-	B32 (120), B32 (121), B32 (122), B32 (123),
-	B32 (124), B32 (125), B32 (126), B32 (127),
-	B32 (128), B32 (129), B32 (130), B32 (131),
-	B32 (132), B32 (133), B32 (134), B32 (135),
-	B32 (136), B32 (137), B32 (138), B32 (139),
-	B32 (140), B32 (141), B32 (142), B32 (143),
-	B32 (144), B32 (145), B32 (146), B32 (147),
-	B32 (148), B32 (149), B32 (150), B32 (151),
-	B32 (152), B32 (153), B32 (154), B32 (155),
-	B32 (156), B32 (157), B32 (158), B32 (159),
-	B32 (160), B32 (161), B32 (162), B32 (163),
-	B32 (164), B32 (165), B32 (166), B32 (167),
-	B32 (168), B32 (169), B32 (170), B32 (171),
-	B32 (172), B32 (173), B32 (174), B32 (175),
-	B32 (176), B32 (177), B32 (178), B32 (179),
-	B32 (180), B32 (181), B32 (182), B32 (183),
-	B32 (184), B32 (185), B32 (186), B32 (187),
-	B32 (188), B32 (189), B32 (190), B32 (191),
-	B32 (192), B32 (193), B32 (194), B32 (195),
-	B32 (196), B32 (197), B32 (198), B32 (199),
-	B32 (200), B32 (201), B32 (202), B32 (203),
-	B32 (204), B32 (205), B32 (206), B32 (207),
-	B32 (208), B32 (209), B32 (210), B32 (211),
-	B32 (212), B32 (213), B32 (214), B32 (215),
-	B32 (216), B32 (217), B32 (218), B32 (219),
-	B32 (220), B32 (221), B32 (222), B32 (223),
-	B32 (224), B32 (225), B32 (226), B32 (227),
-	B32 (228), B32 (229), B32 (230), B32 (231),
-	B32 (232), B32 (233), B32 (234), B32 (235),
-	B32 (236), B32 (237), B32 (238), B32 (239),
-	B32 (240), B32 (241), B32 (242), B32 (243),
-	B32 (244), B32 (245), B32 (246), B32 (247),
-	B32 (248), B32 (249), B32 (250), B32 (251),
-	B32 (252), B32 (253), B32 (254), B32 (255)
-};
-
-#if UCHAR_MAX == 255
-#define uchar_in_range(c) true
-#else
-#define uchar_in_range(c) ((c) <= 255)
-#endif
-
-/* Return true if CH is a character from the Base32 alphabet, and
-   false otherwise.  Note that '=' is padding and not considered to be
-   part of the alphabet.  */
-bool isbase32(char ch)
-{
-	return uchar_in_range(to_uchar(ch)) && 0 <= b32[to_uchar(ch)];
-}
-
-/* Decode base32 encoded input array IN of length INLEN to output
-   array OUT that can hold *OUTLEN bytes.  Return true if decoding was
-   successful, i.e. if the input was valid base32 data, false
-   otherwise.  If *OUTLEN is too small, as many bytes as possible will
-   be written to OUT.  On return, *OUTLEN holds the length of decoded
-   bytes in OUT.  Note that as soon as any non-alphabet characters are
-   encountered, decoding is stopped and false is returned.  This means
-   that, when applicable, you must remove any line terminators that is
-   part of the data stream before calling this function.  */
-bool base32_decode(const char *in, size_t inlen, char *out, size_t *outlen)
-{
-	size_t outleft = *outlen;
-
-	while (inlen >= 2) {
-		if (!isbase32(in[0]) || !isbase32(in[1])) {
-			break;
-		}
-
-		if (outleft) {
-			*out++ = ((b32[to_uchar(in[0])] << 3)
-			          | (b32[to_uchar(in[1])] >> 2));
-			outleft--;
-		}
-
-		if (inlen == 2) {
-			break;
-		}
-
-		if (in[2] == '=') {
-			if (inlen != 8) {
-				break;
-			}
-			
-			if ((in[3] != '=') ||
-			    (in[4] != '=') ||
-			    (in[5] != '=') ||
-			    (in[6] != '=') ||
-			    (in[7] != '=')) {
-				break;
-			}
-		} else {
-			if (!isbase32(in[2]) || !isbase32(in[3])) {
-				break;
-			}
-
-			if (outleft) {
-				*out++ = ((b32[to_uchar(in[1])] << 6)
-				          | ((b32[to_uchar(in[2])] << 1) & 0x3E)
-				          | (b32[to_uchar(in[3])] >> 4));
-				outleft--;
-			}
-			
-			if (inlen == 4) {
-				break;
-			}
-			
-			if (in[4] == '=') {
-				if (inlen != 8) {
-					break;
-				}
-				
-				if ((in[5] != '=') ||
-				    (in[6] != '=') ||
-				    (in[7] != '=')) {
-					break;
-				}
-			} else {
-				if (!isbase32 (in[3]) || !isbase32(in[4])) {
-					break;
-				}
-				
-				if (outleft) {
-					*out++ = ((b32[to_uchar(in[3])] << 4)
-					        | (b32[to_uchar(in[4])] >> 1));
-					outleft--;
-				}
-
-				if (inlen == 5) {
-					break;
-				}
-
-				if (in[5] == '=') {
-					if (inlen != 8) {
-						break;
-					}
-					
-					if ((in[6] != '=')
-					    || (in[7] != '=')) {
-						break;
-					}
-				} else {
-					if (!isbase32 (in[5])
-					    || !isbase32 (in[6])) {
-						break;
-					}
-					
-					if (outleft) {
-						*out++ = ((b32[to_uchar(in[4])]
-						           << 7)
-						  | (b32[to_uchar(in[5])] << 2)
-						  | (b32[to_uchar(in[6])]
-						     >> 3));
-						outleft--;
-					}
-
-					if (inlen == 7) {
-						break;
-					}
-
-					if (in[7] == '=') {
-						if (inlen != 8) {
-							break;
-						}
-					} else {
-						if (!isbase32 (in[7])) {
-							break;
-						}
-						
-						if (outleft) {
-							*out++ =
-							  ((b32[to_uchar(in[6])]
-							   << 5) | (b32[
-							     to_uchar(in[7])]));
-							outleft--;
-						}
-					}
-				}
-			}
-		}
-		
-		in += 8;
-		inlen -= 8;
-	}
-	
-	*outlen -= outleft;
-	
-	if (inlen != 0) {
-		return false;
-	}
-
-	return true;
-}
-
-/* Allocate an output buffer in *OUT, and decode the base32 encoded
-   data stored in IN of size INLEN to the *OUT buffer.  On return, the
-   size of the decoded data is stored in *OUTLEN.  OUTLEN may be NULL,
-   if the caller is not interested in the decoded length.  *OUT may be
-   NULL to indicate an out of memory error, in which case *OUTLEN
-   contains the size of the memory block needed.  The function returns
-   true on successful decoding and memory allocation errors.  (Use the
-   *OUT and *OUTLEN parameters to differentiate between successful
-   decoding and memory error.)  The function returns false if the
-   input was invalid, in which case *OUT is NULL and *OUTLEN is
-   undefined. */
-bool base32_decode_alloc(const char *in, size_t inlen, char **out,
-                         size_t *outlen)
-{
-	/* This may allocate a few bytes too much, depending on input,
-	   but it's not worth the extra CPU time to compute the exact amount.
-	   The exact amount is 5 * inlen / 8, minus 1 if the input ends
-	   with "=" and minus another 1 if the input ends with "==", etc.
-	   Dividing before multiplying avoids the possibility of overflow.  */
-	size_t needlen = 5 * (inlen / 8) + 4;
-
-	*out = malloc(needlen);
-	if (!*out) {
-		return true;
-	}
-
-	if (!base32_decode(in, inlen, *out, &needlen)) {
-		free (*out);
-		*out = NULL;
-		return false;
-	}
-
-	if (outlen) {
-		*outlen = needlen;
-	}
-
-	return true;
-}
-
-#ifdef MAIN
-
-#include <stddef.h>
-#include <stdbool.h>
-#include <string.h>
-#include <stdio.h>
-#include "base32.h"
-
-int main(int argc, char **argv) {
-	int i = 1;
-	size_t inlen, outlen, argvlen;
-	char *out;
-	char *in;
-	bool ok;
-
-	while (argc > 1) {
-		argv++; argc--;
-		argvlen = strlen(*argv);
-
-		outlen = base32_encode_alloc(*argv, argvlen, &out);
-
-		if (out == NULL && outlen == 0 && inlen != 0) {
-			fprintf(stderr, "ERROR(encode): input too long: %zd\n",
-			        outlen);
-			return 1;
-		}
-
-		if (out == NULL) {
-			fprintf(stderr, "ERROR(encode): memory allocation error"
-			        "\n");
-			return 1;
-		}
-
-		ok = base32_decode_alloc(out, outlen, &in, &inlen);
-
-		if (!ok) {
-			fprintf(stderr, "ERROR(decode): input was not valid "
-			        "base32: `%s'\n", out);
-			return 1;
-		}
-
-		if (in == NULL) {
-			fprintf(stderr, "ERROR(decode): memory allocation "
-			        "error\n");
-		}
-
-		if ((inlen != argvlen) ||
-		    strcmp(*argv, in) != 0) {
-			fprintf(stderr, "ERROR(encode/decode): input `%s' and "
-			        "output `%s'\n", *argv, in);
-			return 1;
-		}
-		printf("INPUT: `%s'\nENCODE: `%s'\nDECODE: `%s'\n", *argv, out,
-		       in);
-	}
-}
-
-#endif
diff --git a/src/common/base32.h b/src/common/base32.h
deleted file mode 100644
index 45df9fa..0000000
--- a/src/common/base32.h
+++ /dev/null
@@ -1,121 +0,0 @@
-/* base32.h -- Encode binary data using printable characters.
-   Copyright (C) 2004, 2005, 2006, 2010 Free Software Foundation, Inc.
-   Written by Ondřej Surý & Simon Josefsson.
-
-   This program is free software; you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2, or (at your option)
-   any later version.
-
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
-
-   You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software Foundation,
-   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
-
-#ifndef _BASE32_H_
-#define _BASE32_H_
-
-/* Get size_t. */
-#include <stddef.h>
-
-/* Get bool. */
-#include <stdbool.h>
-
-/*!
- * \brief Counts the size of the Base32-encoded output for given input length.
- *
- * \note This uses that the expression (n+(k-1))/k means the smallest
- *       integer >= n/k, i.e., the ceiling of n/k.
- */
-#define BASE32_LENGTH(inlen) ((((inlen) + 4) / 5) * 8)
-
-/*!
- * \brief Checks if the given character belongs to the Base32 alphabet.
- *
- * \param ch Character to check.
- *
- * \retval true if \a ch belongs to the Base32 alphabet.
- * \retval false otherwise.
- */
-extern bool isbase32(char ch);
-
-/*!
- * \brief Encodes the given character array using Base32 encoding.
- *
- * If \a outlen is less than BASE32_LENGTH(\a inlen), the function writes as
- * many bytes as possible to the output buffer. If \a outlen is more than
- * BASE32_LENGTH(\a inlen), the output will be zero-terminated.
- *
- * \param in Input array of characters.
- * \param inlen Length of the input array.
- * \param out Output buffer.
- * \param outlen Size of the output buffer.
- */
-extern void base32_encode(const char *in, size_t inlen, char *out,
-                          size_t outlen);
-
-/*!
- * \brief Encodes the given character array using Base32 encoding and allocates
- *        space for the output.
- *
- * \param in Input array of characters.
- * \param inlen Length of the input array.
- * \param out Output buffer.
- *
- * \return Size of the allocated output buffer (0 if failed).
- */
-extern size_t base32_encode_alloc(const char *in, size_t inlen, char **out);
-
-/*!
- * \brief Decodes the given character array in Base32 encoding.
- *
- * If \a *outlen is too small, as many bytes as possible will be written to
- * \a out. On return, \a *outlen holds the length of decoded bytes in \a out.
- *
- * \note As soon as any non-alphabet characters are encountered, decoding is
- *       stopped and false is returned.  This means that, when applicable, you
- *       must remove any line terminators that is part of the data stream before
- *       calling this function.
- *
- * \param in Input array of characters.
- * \param inlen Length of the input array.
- * \param out Output buffer.
- * \param outlen Size of the output buffer.
- *
- * \retval true if decoding was successful, i.e. if the input was valid base32
- *              data.
- * \retval false otherwise.
- */
-extern bool base32_decode(const char *in, size_t inlen, char *out,
-                          size_t *outlen);
-
-/*!
- * \brief Allocate an output buffer and decode the base32 encoded data to it.
- *
- * On return, the size of the decoded data is stored in \a *outlen. \a outlen
- * may be NULL, if the caller is not interested in the decoded length. \a *out
- * may be NULL to indicate an out of memory error, in which case \a *outlen
- * contains the size of the memory block needed.
- *
- * \param in Input array of characters.
- * \param inlen Length of the input array.
- * \param out Output buffer. \a *out may be NULL to indicate an out of memory
- *            error in which case \a *outlen contains the size of the memory
- *            block needed
- * \param outlen Size of the output buffer. May be NULL, if the caller is not
- *               interested in the decoded length
- *
- * \retval true on successful decoding and memory allocation errors. (Use the
- *              \a *out and \a *outlen parameters to differentiate between
- *              successful decoding and memory error.)
- * \retval false if the input was invalid, in which case \a *out is NULL and
- *               \a *outlen is undefined.
- */
-extern bool base32_decode_alloc(const char *in, size_t inlen, char **out,
-                                size_t *outlen);
-
-#endif /* _BASE32_H_ */
diff --git a/src/common/base32hex.c b/src/common/base32hex.c
index cd2d2ce..456d79b 100644
--- a/src/common/base32hex.c
+++ b/src/common/base32hex.c
@@ -1,562 +1,421 @@
-/* base32hex.c -- Encode binary data using printable characters.
-   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2006, 2010 Free Software
-   Foundation, Inc.
-
-   This program is free software; you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2, or (at your option)
-   any later version.
-
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
-
-   You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software Foundation,
-   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
-
-/* Adapted from base32.{h,c}.  base32.{h,c} was adapted from
- * base64.{h,c} by Ondřej Surý.  base64.{h,c} was written by Simon
- * Josefsson.  Partially adapted from GNU MailUtils
- * (mailbox/filter_trans.c, as of 2004-11-28).  Improved by review
- * from Paul Eggert, Bruno Haible, and Stepan Kasal.
- *
- * See also RFC 4648 <http://www.ietf.org/rfc/rfc4648.txt>.
- *
- * Be careful with error checking.  Here is how you would typically
- * use these functions:
- *
- * bool ok = base32hex_decode_alloc (in, inlen, &out, &outlen);
- * if (!ok)
- *   FAIL: input was not valid base32hex
- * if (out == NULL)
- *   FAIL: memory allocation error
- * OK: data in OUT/OUTLEN
- *
- * size_t outlen = base32hex_encode_alloc (in, inlen, &out);
- * if (out == NULL && outlen == 0 && inlen != 0)
- *   FAIL: input too long
- * if (out == NULL)
- *   FAIL: memory allocation error
- * OK: data in OUT/OUTLEN.
- *
- */
+/*  Copyright (C) 2011 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
 
-/* Get prototype. */
-#include "base32hex.h"
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
 
-/* Get malloc. */
-#include <stdlib.h>
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
 
-/* Get UCHAR_MAX. */
-#include <limits.h>
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
 
-/* C89 compliant way to cast 'char' to 'unsigned char'. */
-static inline unsigned char to_uchar(char ch)
-{
-	return ch;
-}
+#include "base32hex.h"
 
-/* Base32hex encode IN array of size INLEN into OUT array of size OUTLEN.
-   If OUTLEN is less than BASE32HEX_LENGTH(INLEN), write as many bytes as
-   possible.  If OUTLEN is larger than BASE32HEX_LENGTH(INLEN), also zero
-   terminate the output buffer. */
-void base32hex_encode(const char *in, size_t inlen, char *out, size_t outlen)
+#include <stdlib.h>			// malloc
+#include <stdint.h>			// uint8_t
+
+/*! \brief Maximal length of binary input to Base32hex encoding. */
+#define MAX_BIN_DATA_LEN	((INT32_MAX / 8) * 5)
+
+/*! \brief Base32hex padding character. */
+const uint8_t base32hex_pad = '=';
+/*! \brief Base32hex alphabet. */
+const uint8_t base32hex_enc[] = "0123456789ABCDEFGHIJKLMNOPQRSTUV";
+
+/*! \brief Indicates bad Base32hex character. */
+#define KO	255
+/*! \brief Indicates Base32hex padding character. */
+#define PD	 32
+
+/*! \brief Transformation and validation table for decoding Base32hex. */
+const uint8_t base32hex_dec[256] = {
+	[  0] = KO, [ 43] = KO, ['V'] = 31, [129] = KO, [172] = KO, [215] = KO,
+	[  1] = KO, [ 44] = KO, ['W'] = KO, [130] = KO, [173] = KO, [216] = KO,
+	[  2] = KO, [ 45] = KO, ['X'] = KO, [131] = KO, [174] = KO, [217] = KO,
+	[  3] = KO, [ 46] = KO, ['Y'] = KO, [132] = KO, [175] = KO, [218] = KO,
+	[  4] = KO, [ 47] = KO, ['Z'] = KO, [133] = KO, [176] = KO, [219] = KO,
+	[  5] = KO, ['0'] =  0, [ 91] = KO, [134] = KO, [177] = KO, [220] = KO,
+	[  6] = KO, ['1'] =  1, [ 92] = KO, [135] = KO, [178] = KO, [221] = KO,
+	[  7] = KO, ['2'] =  2, [ 93] = KO, [136] = KO, [179] = KO, [222] = KO,
+	[  8] = KO, ['3'] =  3, [ 94] = KO, [137] = KO, [180] = KO, [223] = KO,
+	[  9] = KO, ['4'] =  4, [ 95] = KO, [138] = KO, [181] = KO, [224] = KO,
+	[ 10] = KO, ['5'] =  5, [ 96] = KO, [139] = KO, [182] = KO, [225] = KO,
+	[ 11] = KO, ['6'] =  6, ['a'] = 10, [140] = KO, [183] = KO, [226] = KO,
+	[ 12] = KO, ['7'] =  7, ['b'] = 11, [141] = KO, [184] = KO, [227] = KO,
+	[ 13] = KO, ['8'] =  8, ['c'] = 12, [142] = KO, [185] = KO, [228] = KO,
+	[ 14] = KO, ['9'] =  9, ['d'] = 13, [143] = KO, [186] = KO, [229] = KO,
+	[ 15] = KO, [ 58] = KO, ['e'] = 14, [144] = KO, [187] = KO, [230] = KO,
+	[ 16] = KO, [ 59] = KO, ['f'] = 15, [145] = KO, [188] = KO, [231] = KO,
+	[ 17] = KO, [ 60] = KO, ['g'] = 16, [146] = KO, [189] = KO, [232] = KO,
+	[ 18] = KO, ['='] = PD, ['h'] = 17, [147] = KO, [190] = KO, [233] = KO,
+	[ 19] = KO, [ 62] = KO, ['i'] = 18, [148] = KO, [191] = KO, [234] = KO,
+	[ 20] = KO, [ 63] = KO, ['j'] = 19, [149] = KO, [192] = KO, [235] = KO,
+	[ 21] = KO, [ 64] = KO, ['k'] = 20, [150] = KO, [193] = KO, [236] = KO,
+	[ 22] = KO, ['A'] = 10, ['l'] = 21, [151] = KO, [194] = KO, [237] = KO,
+	[ 23] = KO, ['B'] = 11, ['m'] = 22, [152] = KO, [195] = KO, [238] = KO,
+	[ 24] = KO, ['C'] = 12, ['n'] = 23, [153] = KO, [196] = KO, [239] = KO,
+	[ 25] = KO, ['D'] = 13, ['o'] = 24, [154] = KO, [197] = KO, [240] = KO,
+	[ 26] = KO, ['E'] = 14, ['p'] = 25, [155] = KO, [198] = KO, [241] = KO,
+	[ 27] = KO, ['F'] = 15, ['q'] = 26, [156] = KO, [199] = KO, [242] = KO,
+	[ 28] = KO, ['G'] = 16, ['r'] = 27, [157] = KO, [200] = KO, [243] = KO,
+	[ 29] = KO, ['H'] = 17, ['s'] = 28, [158] = KO, [201] = KO, [244] = KO,
+	[ 30] = KO, ['I'] = 18, ['t'] = 29, [159] = KO, [202] = KO, [245] = KO,
+	[ 31] = KO, ['J'] = 19, ['u'] = 30, [160] = KO, [203] = KO, [246] = KO,
+	[ 32] = KO, ['K'] = 20, ['v'] = 31, [161] = KO, [204] = KO, [247] = KO,
+	[ 33] = KO, ['L'] = 21, ['w'] = KO, [162] = KO, [205] = KO, [248] = KO,
+	[ 34] = KO, ['M'] = 22, ['x'] = KO, [163] = KO, [206] = KO, [249] = KO,
+	[ 35] = KO, ['N'] = 23, ['y'] = KO, [164] = KO, [207] = KO, [250] = KO,
+	[ 36] = KO, ['O'] = 24, ['z'] = KO, [165] = KO, [208] = KO, [251] = KO,
+	[ 37] = KO, ['P'] = 25, [123] = KO, [166] = KO, [209] = KO, [252] = KO,
+	[ 38] = KO, ['Q'] = 26, [124] = KO, [167] = KO, [210] = KO, [253] = KO,
+	[ 39] = KO, ['R'] = 27, [125] = KO, [168] = KO, [211] = KO, [254] = KO,
+	[ 40] = KO, ['S'] = 28, [126] = KO, [169] = KO, [212] = KO, [255] = KO,
+	[ 41] = KO, ['T'] = 29, [127] = KO, [170] = KO, [213] = KO,
+	[ 42] = KO, ['U'] = 30, [128] = KO, [171] = KO, [214] = KO,
+};
+
+int32_t base32hex_encode(const uint8_t  *in,
+			 const uint32_t in_len,
+			 uint8_t        *out,
+			 const uint32_t out_len)
 {
-	static const char b32str[32] =
-		"0123456789ABCDEFGHIJKLMNOPQRSTUV";
+	uint8_t		rest_len = in_len % 5;
+	const uint8_t	*data = in;
+	const uint8_t	*stop = in + in_len - rest_len;
+	uint8_t		*text = out;
+	uint8_t		num;
+
+	// Checking inputs.
+	if (in == NULL || out == NULL || in_len > MAX_BIN_DATA_LEN ||
+	    out_len < ((in_len + 4) / 5) * 8) {
+		return -1;
+	}
 
-	while (inlen && outlen) {
-		*out++ = b32str[(to_uchar(in[0]) >> 3) & 0x1f];
-		if (!--outlen) {
-			break;
-		}
-		*out++ = b32str[((to_uchar(in[0]) << 2)
-		                + (--inlen ? to_uchar(in[1]) >> 6 : 0))
-		                & 0x1f];
-		if (!--outlen) {
-			break;
-		}
-		*out++ =(inlen
-		         ? b32str[(to_uchar(in[1]) >> 1) & 0x1f]
-		         : '=');
-		if (!--outlen) {
-			break;
-		}
-		*out++ = (inlen
-		         ? b32str[((to_uchar(in[1]) << 4)
-		                   + (--inlen ? to_uchar(in[2]) >> 4 : 0))
-		                   & 0x1f]
-		         : '=');
-		if (!--outlen) {
-			break;
-		}
-		*out++ = (inlen
-		          ? b32str[((to_uchar(in[2]) << 1)
-		                   + (--inlen ? to_uchar(in[3]) >> 7 : 0))
-		                   & 0x1f]
-		          : '=');
-		if (!--outlen) {
-			break;
-		}
-		*out++ = (inlen
-		          ? b32str[(to_uchar(in[3]) >> 2) & 0x1f]
-		          : '=');
-		if (!--outlen)
-		{
-			break;
-		}
-		*out++ = (inlen
-		          ? b32str[((to_uchar(in[3]) << 3)
-		                   + (--inlen ? to_uchar(in[4]) >> 5 : 0))
-		                   & 0x1f]
-		          : '=');
-		if (!--outlen) {
-			break;
-		}
-		*out++ = inlen ? b32str[to_uchar(in[4]) & 0x1f] : '=';
-		if (!--outlen) {
-			break;
-		}
-		if (inlen) {
-			inlen--;
-		}
-		if (inlen) {
-			in += 5;
-		}
+	// Encoding loop takes 5 bytes and creates 8 characters.
+	while (data < stop) {
+		// Computing 1. Base32hex character.
+		num = *data >> 3;
+		*text++ = base32hex_enc[num];
+
+		// Computing 2. Base32hex character.
+		num = (*data++ & 0x07) << 2;
+		num += *data >> 6;
+		*text++ = base32hex_enc[num];
+
+		// Computing 3. Base32hex character.
+		num = (*data & 0x3E) >> 1;
+		*text++ = base32hex_enc[num];
+
+		// Computing 4. Base32hex character.
+		num = (*data++ & 0x01) << 4;
+		num += *data >> 4;
+		*text++ = base32hex_enc[num];
+
+		// Computing 5. Base32hex character.
+		num = (*data++ & 0x0F) << 1;
+		num += *data >> 7;
+		*text++ = base32hex_enc[num];
+
+		// Computing 6. Base32hex character.
+		num = (*data & 0x7C) >> 2;
+		*text++ = base32hex_enc[num];
+
+		// Computing 7. Base32hex character.
+		num = (*data++ & 0x03) << 3;
+		num += *data >> 5;
+		*text++ = base32hex_enc[num];
+
+		// Computing 8. Base32hex character.
+		num = *data++ & 0x1F;
+		*text++ = base32hex_enc[num];
 	}
 
-	if (outlen) {
-		*out = '\0';
+	// Processing of padding, if any.
+	switch (rest_len) {
+	// Input data has 4-byte last block => 1-char padding.
+        case 4:
+		// Computing 1. Base32hex character.
+		num = *data >> 3;
+		*text++ = base32hex_enc[num];
+
+		// Computing 2. Base32hex character.
+		num = (*data++ & 0x07) << 2;
+		num += *data >> 6;
+		*text++ = base32hex_enc[num];
+
+		// Computing 3. Base32hex character.
+		num = (*data & 0x3E) >> 1;
+		*text++ = base32hex_enc[num];
+
+		// Computing 4. Base32hex character.
+		num = (*data++ & 0x01) << 4;
+		num += *data >> 4;
+		*text++ = base32hex_enc[num];
+
+		// Computing 5. Base32hex character.
+		num = (*data++ & 0x0F) << 1;
+		num += *data >> 7;
+		*text++ = base32hex_enc[num];
+
+		// Computing 6. Base32hex character.
+		num = (*data & 0x7C) >> 2;
+		*text++ = base32hex_enc[num];
+
+		// Computing 7. Base32hex character.
+		num = (*data++ & 0x03) << 3;
+		*text++ = base32hex_enc[num];
+
+		// 1 padding character.
+		*text++ = base32hex_pad;
+
+		break;
+	// Input data has 3-byte last block => 3-char padding.
+        case 3:
+		// Computing 1. Base32hex character.
+		num = *data >> 3;
+		*text++ = base32hex_enc[num];
+
+		// Computing 2. Base32hex character.
+		num = (*data++ & 0x07) << 2;
+		num += *data >> 6;
+		*text++ = base32hex_enc[num];
+
+		// Computing 3. Base32hex character.
+		num = (*data & 0x3E) >> 1;
+		*text++ = base32hex_enc[num];
+
+		// Computing 4. Base32hex character.
+		num = (*data++ & 0x01) << 4;
+		num += *data >> 4;
+		*text++ = base32hex_enc[num];
+
+		// Computing 5. Base32hex character.
+		num = (*data++ & 0x0F) << 1;
+		*text++ = base32hex_enc[num];
+
+		// 3 padding characters.
+		*text++ = base32hex_pad;
+		*text++ = base32hex_pad;
+		*text++ = base32hex_pad;
+
+		break;
+	// Input data has 2-byte last block => 4-char padding.
+        case 2:
+		// Computing 1. Base32hex character.
+		num = *data >> 3;
+		*text++ = base32hex_enc[num];
+
+		// Computing 2. Base32hex character.
+		num = (*data++ & 0x07) << 2;
+		num += *data >> 6;
+		*text++ = base32hex_enc[num];
+
+		// Computing 3. Base32hex character.
+		num = (*data & 0x3E) >> 1;
+		*text++ = base32hex_enc[num];
+
+		// Computing 4. Base32hex character.
+		num = (*data++ & 0x01) << 4;
+		*text++ = base32hex_enc[num];
+
+		// 4 padding characters.
+		*text++ = base32hex_pad;
+		*text++ = base32hex_pad;
+		*text++ = base32hex_pad;
+		*text++ = base32hex_pad;
+
+		break;
+	// Input data has 1-byte last block => 6-char padding.
+        case 1:
+		// Computing 1. Base32hex character.
+		num = *data >> 3;
+		*text++ = base32hex_enc[num];
+
+		// Computing 2. Base32hex character.
+		num = (*data++ & 0x07) << 2;
+		*text++ = base32hex_enc[num];
+
+		// 6 padding characters.
+		*text++ = base32hex_pad;
+		*text++ = base32hex_pad;
+		*text++ = base32hex_pad;
+		*text++ = base32hex_pad;
+		*text++ = base32hex_pad;
+		*text++ = base32hex_pad;
+
+		break;
 	}
+
+	return (text - out);
 }
 
-/* Allocate a buffer and store zero terminated base32hex encoded data
-   from array IN of size INLEN, returning BASE32HEX_LENGTH(INLEN), i.e.,
-   the length of the encoded data, excluding the terminating zero.  On
-   return, the OUT variable will hold a pointer to newly allocated
-   memory that must be deallocated by the caller.  If output string
-   length would overflow, 0 is returned and OUT is set to NULL.  If
-   memory allocation failed, OUT is set to NULL, and the return value
-   indicates length of the requested memory block, i.e.,
-   BASE32HEX_LENGTH(inlen) + 1. */
-size_t base32hex_encode_alloc(const char *in, size_t inlen, char **out)
+int32_t base32hex_encode_alloc(const uint8_t  *in,
+			       const uint32_t in_len,
+			       uint8_t        **out)
 {
-	size_t outlen = 1 + BASE32HEX_LENGTH (inlen);
-
-	/* Check for overflow in outlen computation.
-	 *
-	 * If there is no overflow, outlen >= inlen.
-	 *
-	 * If the operation (inlen + 2) overflows then it yields at most +1, so
-	 * outlen is 0.
-	 *
-	 * If the multiplication overflows, we lose at least half of the
-	 * correct value, so the result is < ((inlen + 2) / 3) * 2, which is
-	 * less than (inlen + 2) * 0.66667, which is less than inlen as soon as
-	 * (inlen > 4).
-	 */
-	if (inlen > outlen)
-	{
-		*out = NULL;
-		return 0;
-	}
+	uint32_t out_len = ((in_len + 4) / 5) * 8;
 
-	*out = malloc(outlen);
-	if (!*out) {
-		return outlen;
+	// Checking inputs.
+	if (in_len > MAX_BIN_DATA_LEN) {
+		return -1;
 	}
 
-	base32hex_encode(in, inlen, *out, outlen);
+	// Allocating output buffer.
+	*out = malloc(out_len);
 
-	return outlen - 1;
-}
-
-/* With this approach this file works independent of the charset used
-   (think EBCDIC).  However, it does assume that the characters in the
-   Base32hex alphabet (A-Z2-7) are encoded in 0..255.  POSIX
-   1003.1-2001 require that char and unsigned char are 8-bit
-   quantities, though, taking care of that problem.  But this may be a
-   potential problem on non-POSIX C99 platforms.
-
-   IBM C V6 for AIX mishandles "#define B32(x) ...'x'...", so use "_"
-   as the formal parameter rather than "x".  */
-#define B32(_)					\
-	((_) == '0' ? 0				\
-	 : (_) == '1' ? 1			\
-	 : (_) == '2' ? 2			\
-	 : (_) == '3' ? 3			\
-	 : (_) == '4' ? 4			\
-	 : (_) == '5' ? 5			\
-	 : (_) == '6' ? 6			\
-	 : (_) == '7' ? 7			\
-	 : (_) == '8' ? 8			\
-	 : (_) == '9' ? 9			\
-	 : (_) == 'A' ? 10			\
-	 : (_) == 'B' ? 11			\
-	 : (_) == 'C' ? 12			\
-	 : (_) == 'D' ? 13			\
-	 : (_) == 'E' ? 14			\
-	 : (_) == 'F' ? 15			\
-	 : (_) == 'G' ? 16			\
-	 : (_) == 'H' ? 17			\
-	 : (_) == 'I' ? 18			\
-	 : (_) == 'J' ? 19			\
-	 : (_) == 'K' ? 20			\
-	 : (_) == 'L' ? 21			\
-	 : (_) == 'M' ? 22			\
-	 : (_) == 'N' ? 23			\
-	 : (_) == 'O' ? 24			\
-	 : (_) == 'P' ? 25			\
-	 : (_) == 'Q' ? 26			\
-	 : (_) == 'R' ? 27			\
-	 : (_) == 'S' ? 28			\
-	 : (_) == 'T' ? 29			\
-	 : (_) == 'U' ? 30			\
-	 : (_) == 'V' ? 31			\
-	 : (_) == 'a' ? 10			\
-	 : (_) == 'b' ? 11			\
-	 : (_) == 'c' ? 12			\
-	 : (_) == 'd' ? 13			\
-	 : (_) == 'e' ? 14			\
-	 : (_) == 'f' ? 15			\
-	 : (_) == 'g' ? 16			\
-	 : (_) == 'h' ? 17			\
-	 : (_) == 'i' ? 18			\
-	 : (_) == 'j' ? 19			\
-	 : (_) == 'k' ? 20			\
-	 : (_) == 'l' ? 21			\
-	 : (_) == 'm' ? 22			\
-	 : (_) == 'n' ? 23			\
-	 : (_) == 'o' ? 24			\
-	 : (_) == 'p' ? 25			\
-	 : (_) == 'q' ? 26			\
-	 : (_) == 'r' ? 27			\
-	 : (_) == 's' ? 28			\
-	 : (_) == 't' ? 29			\
-	 : (_) == 'u' ? 30			\
-	 : (_) == 'v' ? 31			\
-	 : -1)
-
-static const signed char b32[0x100] = {
-	B32 (0), B32 (1), B32 (2), B32 (3),
-	B32 (4), B32 (5), B32 (6), B32 (7),
-	B32 (8), B32 (9), B32 (10), B32 (11),
-	B32 (12), B32 (13), B32 (14), B32 (15),
-	B32 (16), B32 (17), B32 (18), B32 (19),
-	B32 (20), B32 (21), B32 (22), B32 (23),
-	B32 (24), B32 (25), B32 (26), B32 (27),
-	B32 (28), B32 (29), B32 (30), B32 (31),
-	B32 (32), B32 (33), B32 (34), B32 (35),
-	B32 (36), B32 (37), B32 (38), B32 (39),
-	B32 (40), B32 (41), B32 (42), B32 (43),
-	B32 (44), B32 (45), B32 (46), B32 (47),
-	B32 (48), B32 (49), B32 (50), B32 (51),
-	B32 (52), B32 (53), B32 (54), B32 (55),
-	B32 (56), B32 (57), B32 (58), B32 (59),
-	B32 (60), B32 (61), B32 (62), B32 (63),
-	B32 (64), B32 (65), B32 (66), B32 (67),
-	B32 (68), B32 (69), B32 (70), B32 (71),
-	B32 (72), B32 (73), B32 (74), B32 (75),
-	B32 (76), B32 (77), B32 (78), B32 (79),
-	B32 (80), B32 (81), B32 (82), B32 (83),
-	B32 (84), B32 (85), B32 (86), B32 (87),
-	B32 (88), B32 (89), B32 (90), B32 (91),
-	B32 (92), B32 (93), B32 (94), B32 (95),
-	B32 (96), B32 (97), B32 (98), B32 (99),
-	B32 (100), B32 (101), B32 (102), B32 (103),
-	B32 (104), B32 (105), B32 (106), B32 (107),
-	B32 (108), B32 (109), B32 (110), B32 (111),
-	B32 (112), B32 (113), B32 (114), B32 (115),
-	B32 (116), B32 (117), B32 (118), B32 (119),
-	B32 (120), B32 (121), B32 (122), B32 (123),
-	B32 (124), B32 (125), B32 (126), B32 (127),
-	B32 (128), B32 (129), B32 (130), B32 (131),
-	B32 (132), B32 (133), B32 (134), B32 (135),
-	B32 (136), B32 (137), B32 (138), B32 (139),
-	B32 (140), B32 (141), B32 (142), B32 (143),
-	B32 (144), B32 (145), B32 (146), B32 (147),
-	B32 (148), B32 (149), B32 (150), B32 (151),
-	B32 (152), B32 (153), B32 (154), B32 (155),
-	B32 (156), B32 (157), B32 (158), B32 (159),
-	B32 (160), B32 (161), B32 (162), B32 (163),
-	B32 (164), B32 (165), B32 (166), B32 (167),
-	B32 (168), B32 (169), B32 (170), B32 (171),
-	B32 (172), B32 (173), B32 (174), B32 (175),
-	B32 (176), B32 (177), B32 (178), B32 (179),
-	B32 (180), B32 (181), B32 (182), B32 (183),
-	B32 (184), B32 (185), B32 (186), B32 (187),
-	B32 (188), B32 (189), B32 (190), B32 (191),
-	B32 (192), B32 (193), B32 (194), B32 (195),
-	B32 (196), B32 (197), B32 (198), B32 (199),
-	B32 (200), B32 (201), B32 (202), B32 (203),
-	B32 (204), B32 (205), B32 (206), B32 (207),
-	B32 (208), B32 (209), B32 (210), B32 (211),
-	B32 (212), B32 (213), B32 (214), B32 (215),
-	B32 (216), B32 (217), B32 (218), B32 (219),
-	B32 (220), B32 (221), B32 (222), B32 (223),
-	B32 (224), B32 (225), B32 (226), B32 (227),
-	B32 (228), B32 (229), B32 (230), B32 (231),
-	B32 (232), B32 (233), B32 (234), B32 (235),
-	B32 (236), B32 (237), B32 (238), B32 (239),
-	B32 (240), B32 (241), B32 (242), B32 (243),
-	B32 (244), B32 (245), B32 (246), B32 (247),
-	B32 (248), B32 (249), B32 (250), B32 (251),
-	B32 (252), B32 (253), B32 (254), B32 (255)
-};
-
-#if UCHAR_MAX == 255
-#define uchar_in_range(c) true
-#else
-#define uchar_in_range(c) ((c) <= 255)
-#endif
+	if (*out == NULL) {
+		return -1;
+	}
 
-/* Return true if CH is a character from the Base32hex alphabet, and
-   false otherwise.  Note that '=' is padding and not considered to be
-   part of the alphabet.  */
-bool isbase32hex(char ch)
-{
-	return uchar_in_range(to_uchar(ch)) && 0 <= b32[to_uchar(ch)];
+	// Encoding data.
+	return base32hex_encode(in, in_len, *out, out_len);
 }
 
-/* Decode base32hex encoded input array IN of length INLEN to output
-   array OUT that can hold *OUTLEN bytes.  Return true if decoding was
-   successful, i.e. if the input was valid base32hex data, false
-   otherwise.  If *OUTLEN is too small, as many bytes as possible will
-   be written to OUT.  On return, *OUTLEN holds the length of decoded
-   bytes in OUT.  Note that as soon as any non-alphabet characters are
-   encountered, decoding is stopped and false is returned.  This means
-   that, when applicable, you must remove any line terminators that is
-   part of the data stream before calling this function.  */
-bool base32hex_decode(const char *in, size_t inlen, char *out, size_t *outlen)
+int32_t base32hex_decode(const uint8_t  *in,
+			 const uint32_t in_len,
+			 uint8_t        *out,
+			 const uint32_t out_len)
 {
-	size_t outleft = *outlen;
+	const uint8_t	*data = in;
+	const uint8_t	*stop = in + in_len;
+	uint8_t		*bin = out;
+	uint8_t		pad_len = 0;
+	uint8_t		c1, c2, c3, c4, c5, c6, c7, c8;
+
+	// Checking inputs.
+	if (in == NULL || out == NULL || (in_len % 8) != 0 ||
+	    in_len > INT32_MAX || out_len < ((in_len + 7) / 8) * 5) {
+		return -1;
+	}
 
-	while (inlen >= 2) {
-		if (!isbase32hex(in[0]) || !isbase32hex(in[1])) {
-			break;
+	// Decoding loop takes 8 characters and creates 5 bytes.
+	while (data < stop) {
+		// Filling and transforming 8 Base32hex chars.
+		c1 = base32hex_dec[*data++];
+		c2 = base32hex_dec[*data++];
+		c3 = base32hex_dec[*data++];
+		c4 = base32hex_dec[*data++];
+		c5 = base32hex_dec[*data++];
+		c6 = base32hex_dec[*data++];
+		c7 = base32hex_dec[*data++];
+		c8 = base32hex_dec[*data++];
+
+		// Check 8. char if is bad or padding.
+		if (c8 >= PD) {
+			if (c8 == PD) {
+				pad_len = 1;
+			} else {
+				return -2;
+			}
 		}
 
-		if (outleft) {
-			*out++ = ((b32[to_uchar(in[0])] << 3)
-			          | (b32[to_uchar(in[1])] >> 2));
-			outleft--;
+		// Check 7. char if is bad or padding (if so, 6. must be too).
+		if (c7 >= PD) {
+			if (c7 == PD && c6 == PD) {
+				pad_len = 3;
+			} else {
+				return -2;
+			}
 		}
 
-		if (inlen == 2) {
-			break;
+		// Check 6. char if is bad or padding.
+		if (c6 >= PD) {
+			if (c6 == PD) {
+				pad_len = 3;
+			} else {
+				return -2;
+			}
 		}
 
-		if (in[2] == '=') {
-			if (inlen != 8) {
-				break;
-			}
-			
-			if ((in[3] != '=') ||
-			    (in[4] != '=') ||
-			    (in[5] != '=') ||
-			    (in[6] != '=') ||
-			    (in[7] != '=')) {
-				break;
-			}
-		} else {
-			if (!isbase32hex(in[2]) || !isbase32hex(in[3])) {
-				break;
+		// Check 5. char if is bad or padding.
+		if (c5 >= PD) {
+			if (c5 == PD) {
+				pad_len = 4;
+			} else {
+				return -2;
 			}
+		}
 
-			if (outleft) {
-				*out++ = ((b32[to_uchar(in[1])] << 6)
-				          | ((b32[to_uchar(in[2])] << 1) & 0x3E)
-				          | (b32[to_uchar(in[3])] >> 4));
-				outleft--;
-			}
-			
-			if (inlen == 4) {
-				break;
-			}
-			
-			if (in[4] == '=') {
-				if (inlen != 8) {
-					break;
-				}
-				
-				if ((in[5] != '=') ||
-				    (in[6] != '=') ||
-				    (in[7] != '=')) {
-					break;
-				}
+		// Check 4. char if is bad or padding (if so, 3. must be too).
+		if (c4 >= PD) {
+			if (c4 == PD && c3 == PD) {
+				pad_len = 6;
 			} else {
-				if (!isbase32hex (in[3]) || !isbase32hex(in[4])) {
-					break;
-				}
-				
-				if (outleft) {
-					*out++ = ((b32[to_uchar(in[3])] << 4)
-					        | (b32[to_uchar(in[4])] >> 1));
-					outleft--;
-				}
-
-				if (inlen == 5) {
-					break;
-				}
-
-				if (in[5] == '=') {
-					if (inlen != 8) {
-						break;
-					}
-					
-					if ((in[6] != '=')
-					    || (in[7] != '=')) {
-						break;
-					}
-				} else {
-					if (!isbase32hex (in[5])
-					    || !isbase32hex (in[6])) {
-						break;
-					}
-					
-					if (outleft) {
-						*out++ = ((b32[to_uchar(in[4])]
-						           << 7)
-						  | (b32[to_uchar(in[5])] << 2)
-						  | (b32[to_uchar(in[6])]
-						     >> 3));
-						outleft--;
-					}
-
-					if (inlen == 7) {
-						break;
-					}
-
-					if (in[7] == '=') {
-						if (inlen != 8) {
-							break;
-						}
-					} else {
-						if (!isbase32hex (in[7])) {
-							break;
-						}
-						
-						if (outleft) {
-							*out++ =
-							  ((b32[to_uchar(in[6])]
-							   << 5) | (b32[
-							     to_uchar(in[7])]));
-							outleft--;
-						}
-					}
-				}
+				return -2;
 			}
 		}
-		
-		in += 8;
-		inlen -= 8;
-	}
-	
-	*outlen -= outleft;
-	
-	if (inlen != 0) {
-		return false;
-	}
-
-	return true;
-}
-
-/* Allocate an output buffer in *OUT, and decode the base32hex encoded
-   data stored in IN of size INLEN to the *OUT buffer.  On return, the
-   size of the decoded data is stored in *OUTLEN.  OUTLEN may be NULL,
-   if the caller is not interested in the decoded length.  *OUT may be
-   NULL to indicate an out of memory error, in which case *OUTLEN
-   contains the size of the memory block needed.  The function returns
-   true on successful decoding and memory allocation errors.  (Use the
-   *OUT and *OUTLEN parameters to differentiate between successful
-   decoding and memory error.)  The function returns false if the
-   input was invalid, in which case *OUT is NULL and *OUTLEN is
-   undefined. */
-bool base32hex_decode_alloc(const char *in, size_t inlen, char **out,
-                         size_t *outlen)
-{
-	/* This may allocate a few bytes too much, depending on input,
-	   but it's not worth the extra CPU time to compute the exact amount.
-	   The exact amount is 5 * inlen / 8, minus 1 if the input ends
-	   with "=" and minus another 1 if the input ends with "==", etc.
-	   Dividing before multiplying avoids the possibility of overflow.  */
-	size_t needlen = 5 * (inlen / 8) + 4;
-
-	*out = malloc(needlen);
-	if (!*out) {
-		return true;
-	}
-
-	if (!base32hex_decode(in, inlen, *out, &needlen)) {
-		free (*out);
-		*out = NULL;
-		return false;
-	}
-
-	if (outlen) {
-		*outlen = needlen;
-	}
-
-	return true;
-}
 
-#ifdef MAIN
-
-#include <stddef.h>
-#include <stdbool.h>
-#include <string.h>
-#include <stdio.h>
-#include "base32hex.h"
-
-int main(int argc, char **argv) {
-	int i = 1;
-	size_t inlen, outlen, argvlen;
-	char *out;
-	char *in;
-	bool ok;
-
-	while (argc > 1) {
-		argv++; argc--;
-		argvlen = strlen(*argv);
-
-		outlen = base32hex_encode_alloc(*argv, argvlen, &out);
+		// Check 3. char if is bad or padding.
+		if (c3 >= PD) {
+			if (c3 == PD) {
+				pad_len = 6;
+			} else {
+				return -2;
+			}
+		}
 
-		if (out == NULL && outlen == 0 && inlen != 0) {
-			fprintf(stderr, "ERROR(encode): input too long: %zd\n",
-			        outlen);
-			return 1;
+		// 1. and 2. chars must not be padding.
+		if (c2 >= PD || c1 >= PD) {
+			return -2;
 		}
 
-		if (out == NULL) {
-			fprintf(stderr, "ERROR(encode): memory allocation error"
-			        "\n");
-			return 1;
+		// Computing of output data based on padding length.
+		switch (pad_len) {
+		// No padding => output has 5 bytess.
+		case 0:
+			*bin++ = (c1 << 3) + (c2 >> 2);
+			*bin++ = (c2 << 6) + (c3 << 1) + (c4 >> 4);
+			*bin++ = (c4 << 4) + (c5 >> 1);
+			*bin++ = (c5 << 7) + (c6 << 2) + (c7 >> 3);
+			*bin++ = (c7 << 5) + c8;
+			break;
+		// 1-char padding => output has 4 bytes.
+		case 1:
+			*bin++ = (c1 << 3) + (c2 >> 2);
+			*bin++ = (c2 << 6) + (c3 << 1) + (c4 >> 4);
+			*bin++ = (c4 << 4) + (c5 >> 1);
+			*bin++ = (c5 << 7) + (c6 << 2) + (c7 >> 3);
+			break;
+		// 3-char padding => output has 3 bytes.
+		case 3:
+			*bin++ = (c1 << 3) + (c2 >> 2);
+			*bin++ = (c2 << 6) + (c3 << 1) + (c4 >> 4);
+			*bin++ = (c4 << 4) + (c5 >> 1);
+			break;
+		// 4-char padding => output has 2 bytes.
+		case 4:
+			*bin++ = (c1 << 3) + (c2 >> 2);
+			*bin++ = (c2 << 6) + (c3 << 1) + (c4 >> 4);
+			break;
+		// 6-char padding => output has 1 byte.
+		case 6:
+			*bin++ = (c1 << 3) + (c2 >> 2);
+			break;
 		}
+	}
 
-		ok = base32hex_decode_alloc(out, outlen, &in, &inlen);
+	return (bin - out);
+}
 
-		if (!ok) {
-			fprintf(stderr, "ERROR(decode): input was not valid "
-			        "base32hex: `%s'\n", out);
-			return 1;
-		}
+int32_t base32hex_decode_alloc(const uint8_t  *in,
+			       const uint32_t in_len,
+			       uint8_t        **out)
+{
+	uint32_t out_len = ((in_len + 7) / 8) * 5;
 
-		if (in == NULL) {
-			fprintf(stderr, "ERROR(decode): memory allocation "
-			        "error\n");
-		}
+	// Allocating output buffer.
+	*out = malloc(out_len);
 
-		if ((inlen != argvlen) ||
-		    strcmp(*argv, in) != 0) {
-			fprintf(stderr, "ERROR(encode/decode): input `%s' and "
-			        "output `%s'\n", *argv, in);
-			return 1;
-		}
-		printf("INPUT: `%s'\nENCODE: `%s'\nDECODE: `%s'\n", *argv, out,
-		       in);
+	if (*out == NULL) {
+		return -1;
 	}
+
+	// Decoding data.
+	return base32hex_decode(in, in_len, *out, out_len);
 }
 
-#endif
diff --git a/src/common/base32hex.h b/src/common/base32hex.h
index 9ac4fa8..c7f3f12 100644
--- a/src/common/base32hex.h
+++ b/src/common/base32hex.h
@@ -1,124 +1,117 @@
-/* base32hex.h -- Encode binary data using printable characters.
-   Copyright (C) 2004, 2005, 2006, 2010 Free Software Foundation, Inc.
-   Written by Ondřej Surý & Simon Josefsson.
+/*  Copyright (C) 2011 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
 
-   This program is free software; you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2, or (at your option)
-   any later version.
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
 
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
-
-   You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software Foundation,
-   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
-
-#ifndef _BASE32HEX_H_
-#define _BASE32HEX_H_
-
-/* Get size_t. */
-#include <stddef.h>
-
-/* Get bool. */
-#include <stdbool.h>
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
 
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
 /*!
- * \brief Counts the size of the Base32Hex-encoded output for given input
- *        length.
+ * \file base32hex.h
  *
- * \note This uses that the expression (n+(k-1))/k means the smallest
- *       integer >= n/k, i.e., the ceiling of n/k.
+ * \author Daniel Salzman <daniel.salzman@nic.cz>
+ *
+ * \brief Base32hex implementation (RFC 4648).
+ *
+ * \note Input Base32hex string can contain a-v characters. These characters
+ *       are considered as A-V equivalent.
+ *
+ * \addtogroup common_lib
+ * @{
  */
-#define BASE32HEX_LENGTH(inlen) ((((inlen) + 4) / 5) * 8)
+
+#ifndef _KNOTD_COMMON__BASE32HEX_H_
+#define _KNOTD_COMMON__BASE32HEX_H_
+
+#include <stdint.h>			// uint8_t
 
 /*!
- * \brief Checks if the given character belongs to the Base32Hex alphabet.
+ * \brief Encodes binary data using Base32hex.
+ *
+ * \note Output data buffer contains Base32hex text string which isn't
+ *       terminated with '\0'!
  *
- * \param ch Character to check.
+ * \param in		Input binary data.
+ * \param in_len	Length of input data.
+ * \param out		Output data buffer.
+ * \param out_len	Size of output buffer.
  *
- * \retval true if \a ch belongs to the Base32Hex alphabet.
- * \retval false otherwise.
+ * \retval >=0		length of output string.
+ * \retval -1		if error.
  */
-extern bool isbase32hex(char ch);
+int32_t base32hex_encode(const uint8_t  *in,
+			 const uint32_t in_len,
+			 uint8_t        *out,
+			 const uint32_t out_len);
 
 /*!
- * \brief Encodes the given character array using Base32 encoding with extended
- *        hex alphabet.
+ * \brief Encodes binary data using Base32hex and output stores to own buffer.
+ *
+ * \note Output data buffer contains Base32hex text string which isn't
+ *       terminated with '\0'!
  *
- * If \a outlen is less than BASE32HEX_LENGTH(\a inlen), the function writes as
- * many bytes as possible to the output buffer. If \a outlen is more than
- * BASE32HEX_LENGTH(\a inlen), the output will be zero-terminated.
+ * \note Output buffer should be deallocated after use.
  *
- * \param in Input array of characters.
- * \param inlen Length of the input array.
- * \param out Output buffer.
- * \param outlen Size of the output buffer.
+ * \param in		Input binary data.
+ * \param in_len	Length of input data.
+ * \param out		Output data buffer.
+ *
+ * \retval >=0		length of output string.
+ * \retval -1		if error.
  */
-extern void base32hex_encode(const char *in, size_t inlen, char *out,
-                          size_t outlen);
+int32_t base32hex_encode_alloc(const uint8_t  *in,
+			       const uint32_t in_len,
+			       uint8_t        **out);
 
 /*!
- * \brief Encodes the given character array using Base32 encoding with extended
- *        hex alphabet and allocates space for the output.
+ * \brief Decodes text data using Base32hex.
+ *
+ * \note Input data needn't be terminated with '\0'.
  *
- * \param in Input array of characters.
- * \param inlen Length of the input array.
- * \param out Output buffer.
+ * \note Input data must be continuous Base32hex string!
  *
- * \return Size of the allocated output buffer (0 if failed).
+ * \param in		Input text data.
+ * \param in_len	Length of input string.
+ * \param out		Output data buffer.
+ * \param out_len	Size of output buffer.
+ *
+ * \retval >=0		length of output data.
+ * \retval -1		if error.
+ * \retval -2		if bad input data.
  */
-extern size_t base32hex_encode_alloc(const char *in, size_t inlen, char **out);
+int32_t base32hex_decode(const uint8_t  *in,
+			 const uint32_t in_len,
+			 uint8_t        *out,
+			 const uint32_t out_len);
 
 /*!
- * \brief Decodes the given character array in Base32 encoding with extended
- *        hex alphabet.
+ * \brief Decodes text data using Base32hex and output stores to own buffer.
+ *
+ * \note Input data needn't be terminated with '\0'.
  *
- * If \a *outlen is too small, as many bytes as possible will be written to
- * \a out. On return, \a *outlen holds the length of decoded bytes in \a out.
+ * \note Input data must be continuous Base32hex string!
  *
- * \note As soon as any non-alphabet characters are encountered, decoding is
- *       stopped and false is returned.  This means that, when applicable, you
- *       must remove any line terminators that is part of the data stream before
- *       calling this function.
+ * \note Output buffer should be deallocated after use.
  *
- * \param in Input array of characters.
- * \param inlen Length of the input array.
- * \param out Output buffer.
- * \param outlen Size of the output buffer.
+ * \param in		Input text data.
+ * \param in_len	Length of input string.
+ * \param out		Output data buffer.
  *
- * \retval true if decoding was successful, i.e. if the input was valid
- *              base32hex data.
- * \retval false otherwise.
+ * \retval >=0		length of output data.
+ * \retval -1		if error.
+ * \retval -2		if bad input data.
  */
-extern bool base32hex_decode(const char *in, size_t inlen, char *out,
-                          size_t *outlen);
+int32_t base32hex_decode_alloc(const uint8_t  *in,
+			       const uint32_t in_len,
+			       uint8_t        **out);
 
-/*!
- * \brief Allocate an output buffer and decode the base32hex encoded data to it.
- *
- * On return, the size of the decoded data is stored in \a *outlen. \a outlen
- * may be NULL, if the caller is not interested in the decoded length. \a *out
- * may be NULL to indicate an out of memory error, in which case \a *outlen
- * contains the size of the memory block needed.
- *
- * \param in Input array of characters.
- * \param inlen Length of the input array.
- * \param out Output buffer. \a *out may be NULL to indicate an out of memory
- *            error in which case \a *outlen contains the size of the memory
- *            block needed
- * \param outlen Size of the output buffer. May be NULL, if the caller is not
- *               interested in the decoded length
- *
- * \retval true on successful decoding and memory allocation errors. (Use the
- *              \a *out and \a *outlen parameters to differentiate between
- *              successful decoding and memory error.)
- * \retval false if the input was invalid, in which case \a *out is NULL and
- *               \a *outlen is undefined.
- */
-extern bool base32hex_decode_alloc(const char *in, size_t inlen, char **out,
-                                size_t *outlen);
+#endif // _KNOTD_COMMON__BASE32HEX_H_
 
-#endif /* _BASE32HEX_H_ */
+/*! @} */
diff --git a/src/common/base64.c b/src/common/base64.c
index f1f601c..a153a70 100644
--- a/src/common/base64.c
+++ b/src/common/base64.c
@@ -1,574 +1,271 @@
-/* base64.c -- Encode binary data using printable characters.
-   Copyright (C) 1999-2001, 2004-2006, 2009-2012 Free Software Foundation, Inc.
-
-   This program is free software; you can redistribute it and/or modify
-   it under the terms of the GNU Lesser General Public License as published by
-   the Free Software Foundation; either version 2.1, or (at your option)
-   any later version.
-
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public License
-   along with this program; if not, see <http://www.gnu.org/licenses/>.  */
-
-/* Written by Simon Josefsson.  Partially adapted from GNU MailUtils
- * (mailbox/filter_trans.c, as of 2004-11-28).  Improved by review
- * from Paul Eggert, Bruno Haible, and Stepan Kasal.
- *
- * See also RFC 4648 <http://www.ietf.org/rfc/rfc4648.txt>.
- *
- * Be careful with error checking.  Here is how you would typically
- * use these functions:
- *
- * bool ok = base64_decode_alloc (in, inlen, &out, &outlen);
- * if (!ok)
- *   FAIL: input was not valid base64
- * if (out == NULL)
- *   FAIL: memory allocation error
- * OK: data in OUT/OUTLEN
- *
- * size_t outlen = base64_encode_alloc (in, inlen, &out);
- * if (out == NULL && outlen == 0 && inlen != 0)
- *   FAIL: input too long
- * if (out == NULL)
- *   FAIL: memory allocation error
- * OK: data in OUT/OUTLEN.
- *
- */
+/*  Copyright (C) 2011 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
 
-#include <config.h>
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
 
-/* Get prototype. */
-#include "base64.h"
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
 
-/* Get malloc. */
-#include <stdlib.h>
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
 
-/* Get UCHAR_MAX. */
-#include <limits.h>
+#include "base64.h"
 
-#include <string.h>
+#include <stdlib.h>			// malloc
+#include <stdint.h>			// uint8_t
+
+/*! \brief Maximal length of binary input to Base64 encoding. */
+#define MAX_BIN_DATA_LEN	((INT32_MAX / 4) * 3)
+
+/*! \brief Base64 padding character. */
+const uint8_t base64_pad = '=';
+/*! \brief Base64 alphabet. */
+const uint8_t base64_enc[] =
+	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+/*! \brief Indicates bad Base64 character. */
+#define KO	255
+/*! \brief Indicates Base64 padding character. */
+#define PD	 64
+
+/*! \brief Transformation and validation table for decoding Base64. */
+const uint8_t base64_dec[256] = {
+	[  0] = KO, ['+'] = 62, ['V'] = 21, [129] = KO, [172] = KO, [215] = KO,
+	[  1] = KO, [ 44] = KO, ['W'] = 22, [130] = KO, [173] = KO, [216] = KO,
+	[  2] = KO, [ 45] = KO, ['X'] = 23, [131] = KO, [174] = KO, [217] = KO,
+	[  3] = KO, [ 46] = KO, ['Y'] = 24, [132] = KO, [175] = KO, [218] = KO,
+	[  4] = KO, ['/'] = 63, ['Z'] = 25, [133] = KO, [176] = KO, [219] = KO,
+	[  5] = KO, ['0'] = 52, [ 91] = KO, [134] = KO, [177] = KO, [220] = KO,
+	[  6] = KO, ['1'] = 53, [ 92] = KO, [135] = KO, [178] = KO, [221] = KO,
+	[  7] = KO, ['2'] = 54, [ 93] = KO, [136] = KO, [179] = KO, [222] = KO,
+	[  8] = KO, ['3'] = 55, [ 94] = KO, [137] = KO, [180] = KO, [223] = KO,
+	[  9] = KO, ['4'] = 56, [ 95] = KO, [138] = KO, [181] = KO, [224] = KO,
+	[ 10] = KO, ['5'] = 57, [ 96] = KO, [139] = KO, [182] = KO, [225] = KO,
+	[ 11] = KO, ['6'] = 58, ['a'] = 26, [140] = KO, [183] = KO, [226] = KO,
+	[ 12] = KO, ['7'] = 59, ['b'] = 27, [141] = KO, [184] = KO, [227] = KO,
+	[ 13] = KO, ['8'] = 60, ['c'] = 28, [142] = KO, [185] = KO, [228] = KO,
+	[ 14] = KO, ['9'] = 61, ['d'] = 29, [143] = KO, [186] = KO, [229] = KO,
+	[ 15] = KO, [ 58] = KO, ['e'] = 30, [144] = KO, [187] = KO, [230] = KO,
+	[ 16] = KO, [ 59] = KO, ['f'] = 31, [145] = KO, [188] = KO, [231] = KO,
+	[ 17] = KO, [ 60] = KO, ['g'] = 32, [146] = KO, [189] = KO, [232] = KO,
+	[ 18] = KO, ['='] = PD, ['h'] = 33, [147] = KO, [190] = KO, [233] = KO,
+	[ 19] = KO, [ 62] = KO, ['i'] = 34, [148] = KO, [191] = KO, [234] = KO,
+	[ 20] = KO, [ 63] = KO, ['j'] = 35, [149] = KO, [192] = KO, [235] = KO,
+	[ 21] = KO, [ 64] = KO, ['k'] = 36, [150] = KO, [193] = KO, [236] = KO,
+	[ 22] = KO, ['A'] =  0, ['l'] = 37, [151] = KO, [194] = KO, [237] = KO,
+	[ 23] = KO, ['B'] =  1, ['m'] = 38, [152] = KO, [195] = KO, [238] = KO,
+	[ 24] = KO, ['C'] =  2, ['n'] = 39, [153] = KO, [196] = KO, [239] = KO,
+	[ 25] = KO, ['D'] =  3, ['o'] = 40, [154] = KO, [197] = KO, [240] = KO,
+	[ 26] = KO, ['E'] =  4, ['p'] = 41, [155] = KO, [198] = KO, [241] = KO,
+	[ 27] = KO, ['F'] =  5, ['q'] = 42, [156] = KO, [199] = KO, [242] = KO,
+	[ 28] = KO, ['G'] =  6, ['r'] = 43, [157] = KO, [200] = KO, [243] = KO,
+	[ 29] = KO, ['H'] =  7, ['s'] = 44, [158] = KO, [201] = KO, [244] = KO,
+	[ 30] = KO, ['I'] =  8, ['t'] = 45, [159] = KO, [202] = KO, [245] = KO,
+	[ 31] = KO, ['J'] =  9, ['u'] = 46, [160] = KO, [203] = KO, [246] = KO,
+	[ 32] = KO, ['K'] = 10, ['v'] = 47, [161] = KO, [204] = KO, [247] = KO,
+	[ 33] = KO, ['L'] = 11, ['w'] = 48, [162] = KO, [205] = KO, [248] = KO,
+	[ 34] = KO, ['M'] = 12, ['x'] = 49, [163] = KO, [206] = KO, [249] = KO,
+	[ 35] = KO, ['N'] = 13, ['y'] = 50, [164] = KO, [207] = KO, [250] = KO,
+	[ 36] = KO, ['O'] = 14, ['z'] = 51, [165] = KO, [208] = KO, [251] = KO,
+	[ 37] = KO, ['P'] = 15, [123] = KO, [166] = KO, [209] = KO, [252] = KO,
+	[ 38] = KO, ['Q'] = 16, [124] = KO, [167] = KO, [210] = KO, [253] = KO,
+	[ 39] = KO, ['R'] = 17, [125] = KO, [168] = KO, [211] = KO, [254] = KO,
+	[ 40] = KO, ['S'] = 18, [126] = KO, [169] = KO, [212] = KO, [255] = KO,
+	[ 41] = KO, ['T'] = 19, [127] = KO, [170] = KO, [213] = KO,
+	[ 42] = KO, ['U'] = 20, [128] = KO, [171] = KO, [214] = KO,
+};
 
-/* C89 compliant way to cast 'char' to 'unsigned char'. */
-static inline unsigned char
-to_uchar (char ch)
+int32_t base64_encode(const uint8_t  *in,
+		      const uint32_t in_len,
+		      uint8_t        *out,
+		      const uint32_t out_len)
 {
-  return ch;
-}
+	uint8_t		rest_len = in_len % 3;
+	const uint8_t	*data = in;
+	const uint8_t	*stop = in + in_len - rest_len;
+	uint8_t		*text = out;
+	uint8_t		num;
+
+	// Checking inputs.
+	if (in == NULL || out == NULL || in_len > MAX_BIN_DATA_LEN ||
+	    out_len < ((in_len + 2) / 3) * 4) {
+		return -1;
+	}
+
+	// Encoding loop takes 3 bytes and creates 4 characters.
+	while (data < stop) {
+		// Computing 1. Base64 character.
+		num = *data >> 2;
+		*text++ = base64_enc[num];
+
+		// Computing 2. Base64 character.
+		num = (*data++ & 0x03) << 4;
+		num += *data >> 4;
+		*text++ = base64_enc[num];
+
+		// Computing 3. Base64 character.
+		num = (*data++ & 0x0F) << 2;
+		num += *data >> 6;
+		*text++ = base64_enc[num];
+
+		// Computing 4. Base64 character.
+		num = *data++ & 0x3F;
+		*text++ = base64_enc[num];
+	}
+
+	// Processing of padding, if any.
+	switch (rest_len) {
+	// Input data has 2-byte last block => 1-char padding.
+        case 2:
+		// Computing 1. Base64 character.
+		num = *data >> 2;
+		*text++ = base64_enc[num];
+
+		// Computing 2. Base64 character.
+		num = (*data++ & 0x03) << 4;
+		num += *data >> 4;
+		*text++ = base64_enc[num];
+
+		// Computing 3. Base64 character.
+		num = (*data++ & 0x0F) << 2;
+		*text++ = base64_enc[num];
+
+		// 1 padding character.
+		*text++ = base64_pad;
 
-/* Base64 encode IN array of size INLEN into OUT array of size OUTLEN.
-   If OUTLEN is less than BASE64_LENGTH(INLEN), write as many bytes as
-   possible.  If OUTLEN is larger than BASE64_LENGTH(INLEN), also zero
-   terminate the output buffer. */
-void
-base64_encode (const char *restrict in, size_t inlen,
-               char *restrict out, size_t outlen)
-{
-  static const char b64str[64] =
-    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
-
-  while (inlen && outlen)
-    {
-      *out++ = b64str[(to_uchar (in[0]) >> 2) & 0x3f];
-      if (!--outlen)
-        break;
-      *out++ = b64str[((to_uchar (in[0]) << 4)
-                       + (--inlen ? to_uchar (in[1]) >> 4 : 0))
-                      & 0x3f];
-      if (!--outlen)
-        break;
-      *out++ =
-        (inlen
-         ? b64str[((to_uchar (in[1]) << 2)
-                   + (--inlen ? to_uchar (in[2]) >> 6 : 0))
-                  & 0x3f]
-         : '=');
-      if (!--outlen)
-        break;
-      *out++ = inlen ? b64str[to_uchar (in[2]) & 0x3f] : '=';
-      if (!--outlen)
-        break;
-      if (inlen)
-        inlen--;
-      if (inlen)
-        in += 3;
-    }
-
-  if (outlen)
-    *out = '\0';
-}
+                break;
+	// Input data has 1-byte last block => 2-char padding.
+        case 1:
+		// Computing 1. Base64 character.
+		num = *data >> 2;
+		*text++ = base64_enc[num];
 
-/* Allocate a buffer and store zero terminated base64 encoded data
-   from array IN of size INLEN, returning BASE64_LENGTH(INLEN), i.e.,
-   the length of the encoded data, excluding the terminating zero.  On
-   return, the OUT variable will hold a pointer to newly allocated
-   memory that must be deallocated by the caller.  If output string
-   length would overflow, 0 is returned and OUT is set to NULL.  If
-   memory allocation failed, OUT is set to NULL, and the return value
-   indicates length of the requested memory block, i.e.,
-   BASE64_LENGTH(inlen) + 1. */
-size_t
-base64_encode_alloc (const char *in, size_t inlen, char **out)
-{
-  size_t outlen = 1 + BASE64_LENGTH (inlen);
-
-  /* Check for overflow in outlen computation.
-   *
-   * If there is no overflow, outlen >= inlen.
-   *
-   * If the operation (inlen + 2) overflows then it yields at most +1, so
-   * outlen is 0.
-   *
-   * If the multiplication overflows, we lose at least half of the
-   * correct value, so the result is < ((inlen + 2) / 3) * 2, which is
-   * less than (inlen + 2) * 0.66667, which is less than inlen as soon as
-   * (inlen > 4).
-   */
-  if (inlen > outlen)
-    {
-      *out = NULL;
-      return 0;
-    }
-
-  *out = malloc (outlen);
-  if (!*out)
-    return outlen;
-
-  base64_encode (in, inlen, *out, outlen);
-
-  return outlen - 1;
-}
+		// Computing 2. Base64 character.
+		num = (*data++ & 0x03) << 4;
+		*text++ = base64_enc[num];
 
-/* With this approach this file works independent of the charset used
-   (think EBCDIC).  However, it does assume that the characters in the
-   Base64 alphabet (A-Za-z0-9+/) are encoded in 0..255.  POSIX
-   1003.1-2001 require that char and unsigned char are 8-bit
-   quantities, though, taking care of that problem.  But this may be a
-   potential problem on non-POSIX C99 platforms.
-
-   IBM C V6 for AIX mishandles "#define B64(x) ...'x'...", so use "_"
-   as the formal parameter rather than "x".  */
-#define B64(_)                                  \
-  ((_) == 'A' ? 0                               \
-   : (_) == 'B' ? 1                             \
-   : (_) == 'C' ? 2                             \
-   : (_) == 'D' ? 3                             \
-   : (_) == 'E' ? 4                             \
-   : (_) == 'F' ? 5                             \
-   : (_) == 'G' ? 6                             \
-   : (_) == 'H' ? 7                             \
-   : (_) == 'I' ? 8                             \
-   : (_) == 'J' ? 9                             \
-   : (_) == 'K' ? 10                            \
-   : (_) == 'L' ? 11                            \
-   : (_) == 'M' ? 12                            \
-   : (_) == 'N' ? 13                            \
-   : (_) == 'O' ? 14                            \
-   : (_) == 'P' ? 15                            \
-   : (_) == 'Q' ? 16                            \
-   : (_) == 'R' ? 17                            \
-   : (_) == 'S' ? 18                            \
-   : (_) == 'T' ? 19                            \
-   : (_) == 'U' ? 20                            \
-   : (_) == 'V' ? 21                            \
-   : (_) == 'W' ? 22                            \
-   : (_) == 'X' ? 23                            \
-   : (_) == 'Y' ? 24                            \
-   : (_) == 'Z' ? 25                            \
-   : (_) == 'a' ? 26                            \
-   : (_) == 'b' ? 27                            \
-   : (_) == 'c' ? 28                            \
-   : (_) == 'd' ? 29                            \
-   : (_) == 'e' ? 30                            \
-   : (_) == 'f' ? 31                            \
-   : (_) == 'g' ? 32                            \
-   : (_) == 'h' ? 33                            \
-   : (_) == 'i' ? 34                            \
-   : (_) == 'j' ? 35                            \
-   : (_) == 'k' ? 36                            \
-   : (_) == 'l' ? 37                            \
-   : (_) == 'm' ? 38                            \
-   : (_) == 'n' ? 39                            \
-   : (_) == 'o' ? 40                            \
-   : (_) == 'p' ? 41                            \
-   : (_) == 'q' ? 42                            \
-   : (_) == 'r' ? 43                            \
-   : (_) == 's' ? 44                            \
-   : (_) == 't' ? 45                            \
-   : (_) == 'u' ? 46                            \
-   : (_) == 'v' ? 47                            \
-   : (_) == 'w' ? 48                            \
-   : (_) == 'x' ? 49                            \
-   : (_) == 'y' ? 50                            \
-   : (_) == 'z' ? 51                            \
-   : (_) == '0' ? 52                            \
-   : (_) == '1' ? 53                            \
-   : (_) == '2' ? 54                            \
-   : (_) == '3' ? 55                            \
-   : (_) == '4' ? 56                            \
-   : (_) == '5' ? 57                            \
-   : (_) == '6' ? 58                            \
-   : (_) == '7' ? 59                            \
-   : (_) == '8' ? 60                            \
-   : (_) == '9' ? 61                            \
-   : (_) == '+' ? 62                            \
-   : (_) == '/' ? 63                            \
-   : -1)
-
-static const signed char b64[0x100] = {
-  B64 (0), B64 (1), B64 (2), B64 (3),
-  B64 (4), B64 (5), B64 (6), B64 (7),
-  B64 (8), B64 (9), B64 (10), B64 (11),
-  B64 (12), B64 (13), B64 (14), B64 (15),
-  B64 (16), B64 (17), B64 (18), B64 (19),
-  B64 (20), B64 (21), B64 (22), B64 (23),
-  B64 (24), B64 (25), B64 (26), B64 (27),
-  B64 (28), B64 (29), B64 (30), B64 (31),
-  B64 (32), B64 (33), B64 (34), B64 (35),
-  B64 (36), B64 (37), B64 (38), B64 (39),
-  B64 (40), B64 (41), B64 (42), B64 (43),
-  B64 (44), B64 (45), B64 (46), B64 (47),
-  B64 (48), B64 (49), B64 (50), B64 (51),
-  B64 (52), B64 (53), B64 (54), B64 (55),
-  B64 (56), B64 (57), B64 (58), B64 (59),
-  B64 (60), B64 (61), B64 (62), B64 (63),
-  B64 (64), B64 (65), B64 (66), B64 (67),
-  B64 (68), B64 (69), B64 (70), B64 (71),
-  B64 (72), B64 (73), B64 (74), B64 (75),
-  B64 (76), B64 (77), B64 (78), B64 (79),
-  B64 (80), B64 (81), B64 (82), B64 (83),
-  B64 (84), B64 (85), B64 (86), B64 (87),
-  B64 (88), B64 (89), B64 (90), B64 (91),
-  B64 (92), B64 (93), B64 (94), B64 (95),
-  B64 (96), B64 (97), B64 (98), B64 (99),
-  B64 (100), B64 (101), B64 (102), B64 (103),
-  B64 (104), B64 (105), B64 (106), B64 (107),
-  B64 (108), B64 (109), B64 (110), B64 (111),
-  B64 (112), B64 (113), B64 (114), B64 (115),
-  B64 (116), B64 (117), B64 (118), B64 (119),
-  B64 (120), B64 (121), B64 (122), B64 (123),
-  B64 (124), B64 (125), B64 (126), B64 (127),
-  B64 (128), B64 (129), B64 (130), B64 (131),
-  B64 (132), B64 (133), B64 (134), B64 (135),
-  B64 (136), B64 (137), B64 (138), B64 (139),
-  B64 (140), B64 (141), B64 (142), B64 (143),
-  B64 (144), B64 (145), B64 (146), B64 (147),
-  B64 (148), B64 (149), B64 (150), B64 (151),
-  B64 (152), B64 (153), B64 (154), B64 (155),
-  B64 (156), B64 (157), B64 (158), B64 (159),
-  B64 (160), B64 (161), B64 (162), B64 (163),
-  B64 (164), B64 (165), B64 (166), B64 (167),
-  B64 (168), B64 (169), B64 (170), B64 (171),
-  B64 (172), B64 (173), B64 (174), B64 (175),
-  B64 (176), B64 (177), B64 (178), B64 (179),
-  B64 (180), B64 (181), B64 (182), B64 (183),
-  B64 (184), B64 (185), B64 (186), B64 (187),
-  B64 (188), B64 (189), B64 (190), B64 (191),
-  B64 (192), B64 (193), B64 (194), B64 (195),
-  B64 (196), B64 (197), B64 (198), B64 (199),
-  B64 (200), B64 (201), B64 (202), B64 (203),
-  B64 (204), B64 (205), B64 (206), B64 (207),
-  B64 (208), B64 (209), B64 (210), B64 (211),
-  B64 (212), B64 (213), B64 (214), B64 (215),
-  B64 (216), B64 (217), B64 (218), B64 (219),
-  B64 (220), B64 (221), B64 (222), B64 (223),
-  B64 (224), B64 (225), B64 (226), B64 (227),
-  B64 (228), B64 (229), B64 (230), B64 (231),
-  B64 (232), B64 (233), B64 (234), B64 (235),
-  B64 (236), B64 (237), B64 (238), B64 (239),
-  B64 (240), B64 (241), B64 (242), B64 (243),
-  B64 (244), B64 (245), B64 (246), B64 (247),
-  B64 (248), B64 (249), B64 (250), B64 (251),
-  B64 (252), B64 (253), B64 (254), B64 (255)
-};
+		// 2 padding character.
+		*text++ = base64_pad;
+		*text++ = base64_pad;
 
-#if UCHAR_MAX == 255
-# define uchar_in_range(c) true
-#else
-# define uchar_in_range(c) ((c) <= 255)
-#endif
-
-/* Return true if CH is a character from the Base64 alphabet, and
-   false otherwise.  Note that '=' is padding and not considered to be
-   part of the alphabet.  */
-bool
-isbase64 (char ch)
-{
-  return uchar_in_range (to_uchar (ch)) && 0 <= b64[to_uchar (ch)];
-}
+                break;
+	}
 
-/* Initialize decode-context buffer, CTX.  */
-void
-base64_decode_ctx_init (struct base64_decode_context *ctx)
-{
-  ctx->i = 0;
+	return (text - out);
 }
 
-/* If CTX->i is 0 or 4, there are four or more bytes in [*IN..IN_END), and
-   none of those four is a newline, then return *IN.  Otherwise, copy up to
-   4 - CTX->i non-newline bytes from that range into CTX->buf, starting at
-   index CTX->i and setting CTX->i to reflect the number of bytes copied,
-   and return CTX->buf.  In either case, advance *IN to point to the byte
-   after the last one processed, and set *N_NON_NEWLINE to the number of
-   verified non-newline bytes accessible through the returned pointer.  */
-static inline char *
-get_4 (struct base64_decode_context *ctx,
-       char const *restrict *in, char const *restrict in_end,
-       size_t *n_non_newline)
+int32_t base64_encode_alloc(const uint8_t  *in,
+			    const uint32_t in_len,
+			    uint8_t        **out)
 {
-  if (ctx->i == 4)
-    ctx->i = 0;
-
-  if (ctx->i == 0)
-    {
-      char const *t = *in;
-      if (4 <= in_end - *in && memchr (t, '\n', 4) == NULL)
-        {
-          /* This is the common case: no newline.  */
-          *in += 4;
-          *n_non_newline = 4;
-          return (char *) t;
-        }
-    }
-
-  {
-    /* Copy non-newline bytes into BUF.  */
-    char const *p = *in;
-    while (p < in_end)
-      {
-        char c = *p++;
-        if (c != '\n')
-          {
-            ctx->buf[ctx->i++] = c;
-            if (ctx->i == 4)
-              break;
-          }
-      }
-
-    *in = p;
-    *n_non_newline = ctx->i;
-    return ctx->buf;
-  }
+	uint32_t out_len = ((in_len + 2) / 3) * 4;
+
+	// Checking inputs.
+	if (in_len > MAX_BIN_DATA_LEN) {
+		return -1;
+	}
+
+	// Allocating output buffer.
+	*out = malloc(out_len);
+
+	if (*out == NULL) {
+		return -1;
+	}
+
+	// Encoding data.
+	return base64_encode(in, in_len, *out, out_len);
 }
 
-#define return_false                            \
-  do                                            \
-    {                                           \
-      *outp = out;                              \
-      return false;                             \
-    }                                           \
-  while (false)
-
-/* Decode up to four bytes of base64-encoded data, IN, of length INLEN
-   into the output buffer, *OUT, of size *OUTLEN bytes.  Return true if
-   decoding is successful, false otherwise.  If *OUTLEN is too small,
-   as many bytes as possible are written to *OUT.  On return, advance
-   *OUT to point to the byte after the last one written, and decrement
-   *OUTLEN to reflect the number of bytes remaining in *OUT.  */
-static inline bool
-decode_4 (char const *restrict in, size_t inlen,
-          char *restrict *outp, size_t *outleft)
+int32_t base64_decode(const uint8_t  *in,
+		      const uint32_t in_len,
+		      uint8_t        *out,
+		      const uint32_t out_len)
 {
-  char *out = *outp;
-  if (inlen < 2)
-    return false;
-
-  if (!isbase64 (in[0]) || !isbase64 (in[1]))
-    return false;
-
-  if (*outleft)
-    {
-      *out++ = ((b64[to_uchar (in[0])] << 2)
-                | (b64[to_uchar (in[1])] >> 4));
-      --*outleft;
-    }
-
-  if (inlen == 2)
-    return_false;
-
-  if (in[2] == '=')
-    {
-      if (inlen != 4)
-        return_false;
-
-      if (in[3] != '=')
-        return_false;
-    }
-  else
-    {
-      if (!isbase64 (in[2]))
-        return_false;
-
-      if (*outleft)
-        {
-          *out++ = (((b64[to_uchar (in[1])] << 4) & 0xf0)
-                    | (b64[to_uchar (in[2])] >> 2));
-          --*outleft;
-        }
-
-      if (inlen == 3)
-        return_false;
-
-      if (in[3] == '=')
-        {
-          if (inlen != 4)
-            return_false;
-        }
-      else
-        {
-          if (!isbase64 (in[3]))
-            return_false;
-
-          if (*outleft)
-            {
-              *out++ = (((b64[to_uchar (in[2])] << 6) & 0xc0)
-                        | b64[to_uchar (in[3])]);
-              --*outleft;
-            }
-        }
-    }
-
-  *outp = out;
-  return true;
+	const uint8_t	*data = in;
+	const uint8_t	*stop = in + in_len;
+	uint8_t		*bin = out;
+	uint8_t		pad_len = 0;
+	uint8_t		c1, c2, c3, c4;
+
+	// Checking inputs.
+	if (in == NULL || out == NULL || (in_len % 4) != 0 ||
+	    in_len > INT32_MAX || out_len < ((in_len + 3) / 4) * 3) {
+		return -1;
+	}
+
+	// Decoding loop takes 4 characters and creates 3 bytes.
+	while (data < stop) {
+		// Filling and transforming 4 Base64 chars.
+		c1 = base64_dec[*data++];
+		c2 = base64_dec[*data++];
+		c3 = base64_dec[*data++];
+		c4 = base64_dec[*data++];
+
+		// Check 4. char if is bad or padding.
+		if (c4 >= PD) {
+			if (c4 == PD) {
+				pad_len = 1;
+			} else {
+				return -2;
+			}
+		}
+
+		// Check 3. char if is bad or padding.
+		if (c3 >= PD) {
+			if (c3 == PD) {
+				pad_len = 2;
+			} else {
+				return -2;
+			}
+		}
+
+		// 1. and 2. chars must not be padding.
+		if (c2 >= PD || c1 >= PD) {
+			return -2;
+		}
+
+		// Computing of output data based on padding length.
+		switch (pad_len) {
+		// No padding => output has 3 bytess.
+		case 0:
+			*bin++ = (c1 << 2) + (c2 >> 4);
+			*bin++ = (c2 << 4) + (c3 >> 2);
+			*bin++ = (c3 << 6) + c4;
+			break;
+		// 1-char padding => output has 2 bytes.
+		case 1:
+			*bin++ = (c1 << 2) + (c2 >> 4);
+			*bin++ = (c2 << 4) + (c3 >> 2);
+			break;
+		// 2-char padding => output has 1 bytes.
+		case 2:
+			*bin++ = (c1 << 2) + (c2 >> 4);
+			break;
+		}
+	}
+
+	return (bin - out);
 }
 
-/* Decode base64-encoded input array IN of length INLEN to output array
-   OUT that can hold *OUTLEN bytes.  The input data may be interspersed
-   with newlines.  Return true if decoding was successful, i.e. if the
-   input was valid base64 data, false otherwise.  If *OUTLEN is too
-   small, as many bytes as possible will be written to OUT.  On return,
-   *OUTLEN holds the length of decoded bytes in OUT.  Note that as soon
-   as any non-alphabet, non-newline character is encountered, decoding
-   is stopped and false is returned.  If INLEN is zero, then process
-   only whatever data is stored in CTX.
-
-   Initially, CTX must have been initialized via base64_decode_ctx_init.
-   Subsequent calls to this function must reuse whatever state is recorded
-   in that buffer.  It is necessary for when a quadruple of base64 input
-   bytes spans two input buffers.
-
-   If CTX is NULL then newlines are treated as garbage and the input
-   buffer is processed as a unit.  */
-
-bool
-base64_decode_ctx (struct base64_decode_context *ctx,
-                   const char *restrict in, size_t inlen,
-                   char *restrict out, size_t *outlen)
+int32_t base64_decode_alloc(const uint8_t  *in,
+			    const uint32_t in_len,
+			    uint8_t        **out)
 {
-  size_t outleft = *outlen;
-  bool ignore_newlines = ctx != NULL;
-  bool flush_ctx = false;
-  unsigned int ctx_i = 0;
-
-  if (ignore_newlines)
-    {
-      ctx_i = ctx->i;
-      flush_ctx = inlen == 0;
-    }
-
-
-  while (true)
-    {
-      size_t outleft_save = outleft;
-      if (ctx_i == 0 && !flush_ctx)
-        {
-          while (true)
-            {
-              /* Save a copy of outleft, in case we need to re-parse this
-                 block of four bytes.  */
-              outleft_save = outleft;
-              if (!decode_4 (in, inlen, &out, &outleft))
-                break;
+	uint32_t out_len = ((in_len + 3) / 4) * 3;
 
-              in += 4;
-              inlen -= 4;
-            }
-        }
-
-      if (inlen == 0 && !flush_ctx)
-        break;
-
-      /* Handle the common case of 72-byte wrapped lines.
-         This also handles any other multiple-of-4-byte wrapping.  */
-      if (inlen && *in == '\n' && ignore_newlines)
-        {
-          ++in;
-          --inlen;
-          continue;
-        }
-
-      /* Restore OUT and OUTLEFT.  */
-      out -= outleft_save - outleft;
-      outleft = outleft_save;
-
-      {
-        char const *in_end = in + inlen;
-        char const *non_nl;
-
-        if (ignore_newlines)
-          non_nl = get_4 (ctx, &in, in_end, &inlen);
-        else
-          non_nl = in;  /* Might have nl in this case. */
-
-        /* If the input is empty or consists solely of newlines (0 non-newlines),
-           then we're done.  Likewise if there are fewer than 4 bytes when not
-           flushing context and not treating newlines as garbage.  */
-        if (inlen == 0 || (inlen < 4 && !flush_ctx && ignore_newlines))
-          {
-            inlen = 0;
-            break;
-          }
-        if (!decode_4 (non_nl, inlen, &out, &outleft))
-          break;
-
-        inlen = in_end - in;
-      }
-    }
-
-  *outlen -= outleft;
-  
-  return inlen == 0;
-}
+	*out = malloc(out_len);
 
-/* Allocate an output buffer in *OUT, and decode the base64 encoded
-   data stored in IN of size INLEN to the *OUT buffer.  On return, the
-   size of the decoded data is stored in *OUTLEN.  OUTLEN may be NULL,
-   if the caller is not interested in the decoded length.  *OUT may be
-   NULL to indicate an out of memory error, in which case *OUTLEN
-   contains the size of the memory block needed.  The function returns
-   true on successful decoding and memory allocation errors.  (Use the
-   *OUT and *OUTLEN parameters to differentiate between successful
-   decoding and memory error.)  The function returns false if the
-   input was invalid, in which case *OUT is NULL and *OUTLEN is
-   undefined. */
-bool
-base64_decode_alloc_ctx (struct base64_decode_context *ctx,
-                         const char *in, size_t inlen, char **out,
-                         size_t *outlen)
-{
-  /* This may allocate a few bytes too many, depending on input,
-     but it's not worth the extra CPU time to compute the exact size.
-     The exact size is 3 * (inlen + (ctx ? ctx->i : 0)) / 4, minus 1 if the
-     input ends with "=" and minus another 1 if the input ends with "==".
-     Dividing before multiplying avoids the possibility of overflow.  */
-  size_t needlen = 3 * (inlen / 4) + 3;
-
-  *out = malloc (needlen);
-  if (!*out)
-    return true;
-
-  if (!base64_decode_ctx (ctx, in, inlen, *out, &needlen))
-    {
-      free (*out);
-      *out = NULL;
-      return false;
-    }
-
-  if (outlen)
-    *outlen = needlen;
-
-  return true;
+	// Allocating output buffer.
+	if (*out == NULL) {
+		return -1;
+	}
+
+	// Decoding data.
+	return base64_decode(in, in_len, *out, out_len);
 }
+
diff --git a/src/common/base64.h b/src/common/base64.h
index aa0b696..8f99891 100644
--- a/src/common/base64.h
+++ b/src/common/base64.h
@@ -1,60 +1,114 @@
-/* base64.h -- Encode binary data using printable characters.
-   Copyright (C) 2004-2006, 2009-2012 Free Software Foundation, Inc.
-   Written by Simon Josefsson.
-
-   This program is free software; you can redistribute it and/or modify
-   it under the terms of the GNU Lesser General Public License as published by
-   the Free Software Foundation; either version 2.1, or (at your option)
-   any later version.
-
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public License
-   along with this program; if not, see <http://www.gnu.org/licenses/>.  */
-
-#ifndef BASE64_H
-# define BASE64_H
-
-/* Get size_t. */
-# include <stddef.h>
-
-/* Get bool. */
-# include <stdbool.h>
-
-/* This uses that the expression (n+(k-1))/k means the smallest
-   integer >= n/k, i.e., the ceiling of n/k.  */
-# define BASE64_LENGTH(inlen) ((((inlen) + 2) / 3) * 4)
-
-struct base64_decode_context
-{
-  unsigned int i;
-  char buf[4];
-};
-
-extern bool isbase64 (char ch);
-
-extern void base64_encode (const char *restrict in, size_t inlen,
-                           char *restrict out, size_t outlen);
-
-extern size_t base64_encode_alloc (const char *in, size_t inlen, char **out);
-
-extern void base64_decode_ctx_init (struct base64_decode_context *ctx);
-
-extern bool base64_decode_ctx (struct base64_decode_context *ctx,
-                               const char *restrict in, size_t inlen,
-                               char *restrict out, size_t *outlen);
-
-extern bool base64_decode_alloc_ctx (struct base64_decode_context *ctx,
-                                     const char *in, size_t inlen,
-                                     char **out, size_t *outlen);
-
-#define base64_decode(in, inlen, out, outlen) \
-        base64_decode_ctx (NULL, in, inlen, out, outlen)
-
-#define base64_decode_alloc(in, inlen, out, outlen) \
-        base64_decode_alloc_ctx (NULL, in, inlen, out, outlen)
-
-#endif /* BASE64_H */
+/*  Copyright (C) 2011 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+/*!
+ * \file base64.h
+ *
+ * \author Daniel Salzman <daniel.salzman@nic.cz>
+ *
+ * \brief Base64 implementation (RFC 4648).
+ *
+ * \addtogroup common_lib
+ * @{
+ */
+
+#ifndef _KNOTD_COMMON__BASE64_H_
+#define _KNOTD_COMMON__BASE64_H_
+
+#include <stdint.h>			// uint8_t
+
+/*!
+ * \brief Encodes binary data using Base64.
+ *
+ * \note Output data buffer contains Base64 text string which isn't
+ *       terminated with '\0'!
+ *
+ * \param in		Input binary data.
+ * \param in_len	Length of input data.
+ * \param out		Output data buffer.
+ * \param out_len	Size of output buffer.
+ *
+ * \retval >=0		length of output string.
+ * \retval -1		if error.
+ */
+int32_t base64_encode(const uint8_t  *in,
+		      const uint32_t in_len,
+		      uint8_t        *out,
+		      const uint32_t out_len);
+
+/*!
+ * \brief Encodes binary data using Base64 and output stores to own buffer.
+ *
+ * \note Output data buffer contains Base64 text string which isn't
+ *       terminated with '\0'!
+ *
+ * \note Output buffer should be deallocated after use.
+ *
+ * \param in		Input binary data.
+ * \param in_len	Length of input data.
+ * \param out		Output data buffer.
+ *
+ * \retval >=0		length of output string.
+ * \retval -1		if error.
+ */
+int32_t base64_encode_alloc(const uint8_t  *in,
+			    const uint32_t in_len,
+			    uint8_t        **out);
+
+/*!
+ * \brief Decodes text data using Base64.
+ *
+ * \note Input data needn't be terminated with '\0'.
+ *
+ * \note Input data must be continuous Base64 string!
+ *
+ * \param in		Input text data.
+ * \param in_len	Length of input string.
+ * \param out		Output data buffer.
+ * \param out_len	Size of output buffer.
+ *
+ * \retval >=0		length of output data.
+ * \retval -1		if error.
+ * \retval -2		if bad input data.
+ */
+int32_t base64_decode(const uint8_t  *in,
+		      const uint32_t in_len,
+		      uint8_t        *out,
+		      const uint32_t out_len);
+
+/*!
+ * \brief Decodes text data using Base64 and output stores to own buffer.
+ *
+ * \note Input data needn't be terminated with '\0'.
+ *
+ * \note Input data must be continuous Base64 string!
+ *
+ * \note Output buffer should be deallocated after use.
+ *
+ * \param in		Input text data.
+ * \param in_len	Length of input string.
+ * \param out		Output data buffer.
+ *
+ * \retval >=0		length of output data.
+ * \retval -1		if error.
+ * \retval -2		if bad input data.
+ */
+int32_t base64_decode_alloc(const uint8_t  *in,
+			    const uint32_t in_len,
+			    uint8_t        **out);
+
+#endif // _KNOTD_COMMON__BASE64_H_
+
+/*! @} */
diff --git a/src/common/errcode.c b/src/common/errcode.c
index 9f5aff3..ff9be63 100644
--- a/src/common/errcode.c
+++ b/src/common/errcode.c
@@ -69,6 +69,7 @@ const error_table_t knot_error_msgs[] = {
 	{KNOT_EIXFRSPACE, "IXFR reply did not fit in."},
 	{KNOT_ECNAME, "CNAME loop found in zone."},
 	{KNOT_ENODIFF, "Cannot create zone diff."},
+	{KNOT_EDSDIGESTLEN, "DS digest length does not match digest type." },
 
 	{KNOT_ERROR, 0}
 };
diff --git a/src/common/errcode.h b/src/common/errcode.h
index 50535ad..0693a0d 100644
--- a/src/common/errcode.h
+++ b/src/common/errcode.h
@@ -82,7 +82,8 @@ enum knot_error {
 	KNOT_ECONN,           /*!< Connection reset. */
 	KNOT_EIXFRSPACE,      /*!< IXFR reply did not fit in. */
 	KNOT_ECNAME,          /*!< CNAME loop found in zone. */
-	KNOT_ENODIFF          /*!< No zone diff can be created. */
+	KNOT_ENODIFF,         /*!< No zone diff can be created. */
+	KNOT_EDSDIGESTLEN     /*!< DS digest length does not match digest type. */
 };
 
 /*! \brief Table linking error messages to error codes. */
diff --git a/src/common/evqueue.c b/src/common/evqueue.c
index 240ced6..efd6d4d 100644
--- a/src/common/evqueue.c
+++ b/src/common/evqueue.c
@@ -19,84 +19,8 @@
 #include <unistd.h>
 #include <config.h>
 
-/* OpenBSD compatibility. */
-#ifndef HAVE_PSELECT
-/*
- * Like select(2) but set the signals to block while waiting in
- * select.  This version is not entirely race condition safe.  Only
- * operating system support can make it so.
- * 
- * Copyright (c) 2001-2011, NLnet Labs. All rights reserved.
- *
- * This software is open source.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * Redistributions of source code must retain the above copyright notice,
- * this list of conditions and the following disclaimer.
- *
- * Redistributions in binary form must reproduce the above copyright notice,
- * this list of conditions and the following disclaimer in the documentation
- * and/or other materials provided with the distribution.
- *
- * Neither the name of the NLNET LABS nor the names of its contributors may
- * be used to endorse or promote products derived from this software without
- * specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
- * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
- * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
- * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
- * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
- * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- * POSSIBILITY OF SUCH DAMAGE.
- */
-#include <sys/time.h>
-#include <sys/types.h>
-#ifdef HAVE_SYS_SELECT_H
-#include <sys/select.h>
-#endif
-#include <unistd.h>
-#include <signal.h>
-
-static int
-pselect (int n,
-	 fd_set *readfds,
-	 fd_set *writefds,
-	 fd_set *exceptfds,
-	 const struct timespec *timeout,
-	 const sigset_t *sigmask)
-{
-	int result;
-	sigset_t saved_sigmask;
-	struct timeval saved_timeout;
-
-	if (sigmask && sigprocmask(SIG_SETMASK, sigmask, &saved_sigmask) == -1)
-		return -1;
-
-	if (timeout) {
-		saved_timeout.tv_sec = timeout->tv_sec;
-		saved_timeout.tv_usec = timeout->tv_nsec / 1000;
-		result = select(n, readfds, writefds, exceptfds, &saved_timeout);
-	} else {
-		result = select(n, readfds, writefds, exceptfds, NULL);
-	}
-	
-	if (sigmask && sigprocmask(SIG_SETMASK, &saved_sigmask, NULL) == -1)
-		return -1;
-
-	return result;
-}
-
-#endif
-
 #include "common/evqueue.h"
+#include "common/fdset.h"
 
 /*! \brief Singleton application-wide event queue. */
 evqueue_t *s_evqueue = 0;
@@ -148,7 +72,8 @@ int evqueue_poll(evqueue_t *q, const struct timespec *ts,
 	FD_SET(q->fds[EVQUEUE_READFD], &rfds);
 
 	/* Wait for events. */
-	int ret = pselect(q->fds[EVQUEUE_READFD] + 1, &rfds, 0, 0, ts, sigmask);
+	int ret = fdset_pselect(q->fds[EVQUEUE_READFD] + 1, &rfds,
+	                        0, 0, ts, sigmask);
 	if (ret < 0) {
 		return -1;
 	}
diff --git a/src/common/evsched.c b/src/common/evsched.c
index 9bfdef0..5e2073a 100644
--- a/src/common/evsched.c
+++ b/src/common/evsched.c
@@ -72,6 +72,7 @@ evsched_t *evsched_new()
 	if (!s) {
 		return 0;
 	}
+	memset(s, 0, sizeof(evsched_t));
 
 	/* Initialize event calendar. */
 	pthread_mutex_init(&s->rl, 0);
@@ -183,10 +184,18 @@ event_t* evsched_next(evsched_t *s)
 
 			/* Immediately return. */
 			if (timercmp_ge(&dt, &next_ev->tv)) {
-				s->current = next_ev;
-				heap_delmin(&s->heap);
+				s->cur = next_ev;
+                heap_delmin(&s->heap);
 				pthread_mutex_unlock(&s->mx);
 				pthread_mutex_lock(&s->rl);
+
+				/* Check back for late cancellation. */
+				if (s->cur == NULL) {
+					pthread_mutex_unlock(&s->rl);
+					pthread_mutex_lock(&s->mx);
+					continue;
+                }
+				
 				return next_ev;
 			}
 
@@ -215,8 +224,8 @@ int evsched_event_finished(evsched_t *s)
 	}
 
 	/* Mark as finished. */
-	if (s->current) {
-		s->current = 0;
+	if (s->cur) {
+		s->cur = NULL;
 		pthread_mutex_unlock(&s->rl);
 		return 0;
 	}
@@ -308,6 +317,15 @@ int evsched_cancel(evsched_t *s, event_t *ev)
 	if ((found = heap_find(&s->heap, ev))) {
 		heap_delete(&s->heap, found);
 	}
+	
+	/* Check if not being processed, invalidate if yes.
+	 * Could happen if next 'cur' was set, but
+	 * the evsched_next() waits until we release rl.
+	 */
+	if (s->cur == ev) {
+		s->cur = NULL; /* Invalidate */
+        found = 1; /* Mark as found (although not in heap). */
+	}
 
 	/* Unlock calendar. */
 	pthread_cond_broadcast(&s->notify);
diff --git a/src/common/evsched.h b/src/common/evsched.h
index 47bf672..9078749 100644
--- a/src/common/evsched.h
+++ b/src/common/evsched.h
@@ -89,7 +89,7 @@ typedef enum evsched_ev_t {
  */
 typedef struct {
 	pthread_mutex_t rl;      /*!< Event running lock. */
-	event_t *current;        /*!< Current running event. */
+	volatile event_t *cur;   /*!< Current running event. */
 	pthread_mutex_t mx;      /*!< Event queue locking. */
 	pthread_cond_t notify;   /*!< Event queue notification. */
 	struct heap heap;
diff --git a/src/common/fdset.c b/src/common/fdset.c
index c915e01..6c5f0d3 100644
--- a/src/common/fdset.c
+++ b/src/common/fdset.c
@@ -203,3 +203,83 @@ int fdset_sweep(fdset_t* fdset, void(*cb)(fdset_t*, int, void*), void *data)
 	
 	return sweeped;
 }
+
+/* OpenBSD compatibility. */
+#ifndef HAVE_PSELECT
+/*
+ * Like select(2) but set the signals to block while waiting in
+ * select.  This version is not entirely race condition safe.  Only
+ * operating system support can make it so.
+ * 
+ * Copyright (c) 2001-2011, NLnet Labs. All rights reserved.
+ *
+ * This software is open source.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * Neither the name of the NLNET LABS nor the names of its contributors may
+ * be used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+#include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <signal.h>
+
+static int
+pselect (int n,
+	 fd_set *readfds,
+	 fd_set *writefds,
+	 fd_set *exceptfds,
+	 const struct timespec *timeout,
+	 const sigset_t *sigmask)
+{
+	int result;
+	sigset_t saved_sigmask;
+	struct timeval saved_timeout;
+
+	if (sigmask && sigprocmask(SIG_SETMASK, sigmask, &saved_sigmask) == -1)
+		return -1;
+
+	if (timeout) {
+		saved_timeout.tv_sec = timeout->tv_sec;
+		saved_timeout.tv_usec = timeout->tv_nsec / 1000;
+		result = select(n, readfds, writefds, exceptfds, &saved_timeout);
+	} else {
+		result = select(n, readfds, writefds, exceptfds, NULL);
+	}
+	
+	if (sigmask && sigprocmask(SIG_SETMASK, &saved_sigmask, NULL) == -1)
+		return -1;
+
+	return result;
+}
+
+#endif
+
+int fdset_pselect(int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
+                  const struct timespec *timeout, const sigset_t *sigmask)
+{
+	return pselect(n, readfds, writefds, exceptfds, timeout, sigmask);
+}
diff --git a/src/common/fdset.h b/src/common/fdset.h
index 4038083..12fc5c7 100644
--- a/src/common/fdset.h
+++ b/src/common/fdset.h
@@ -33,6 +33,9 @@
 #define _KNOTD_FDSET_H_
 
 #include <stddef.h>
+#ifdef HAVE_SYS_SELECT_H
+#include <sys/select.h>
+#endif
 #include "skip-list.h"
 #include "mempattern.h"
 
@@ -232,6 +235,20 @@ int fdset_set_watchdog(fdset_t* fdset, int fd, int interval);
  */
 int fdset_sweep(fdset_t* fdset, void(*cb)(fdset_t*, int, void*), void *data);
 
+/*!
+ * \brief pselect(2) compatibility wrapper.
+ * \param n Number of file descriptors.
+ * \param readfds Array of fds to read.
+ * \param writefds Array of fds to write.
+ * \param exceptfds Array of fds for exceptions.
+ * \param timeout Upper bound of time elapsed.
+ * \param sigmask If != NULL, replaces current signal mask.
+ * \return Number of events or -1 if fails.
+ */
+int fdset_pselect(int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
+                  const struct timespec *timeout, const sigset_t *sigmask);
+
+
 #endif /* _KNOTD_FDSET_H_ */
 
 /*! @} */
diff --git a/src/common/general-tree.c b/src/common/general-tree.c
index e1048e7..1edd0f3 100644
--- a/src/common/general-tree.c
+++ b/src/common/general-tree.c
@@ -141,6 +141,7 @@ void gen_tree_clear(general_tree_t *tree)
 {
 	MOD_TREE_DESTROY(tree->tree, general_tree_node, avl, NULL,
 	                 gen_rem_func, NULL);
+	tree->tree->th_root = NULL; /* Invalidate tree root. */
 }
 
 //static void add_node_to_tree(void *n, void *data)
diff --git a/src/common/mempattern.c b/src/common/mempattern.c
index 5982e18..acf6eac 100644
--- a/src/common/mempattern.c
+++ b/src/common/mempattern.c
@@ -19,6 +19,7 @@
 #include <string.h>
 #include <sys/resource.h>
 #include <config.h>
+#include <stdarg.h>
 
 #include "common/slab/alloc-common.h"
 
@@ -45,6 +46,44 @@ int mreserve(char **p, size_t tlen, size_t min, size_t allow, size_t *reserved)
 	return 0;
 }
 
+char* sprintf_alloc(const char *fmt, ...)
+{
+	int size = 100;
+	char *p = NULL, *np = NULL;
+	va_list ap;
+	
+	if ((p = malloc(size)) == NULL)
+		return NULL;
+	
+	while (1) {
+		
+		/* Try to print in the allocated space. */
+		va_start(ap, fmt);
+		int n = vsnprintf(p, size, fmt, ap);
+		va_end(ap);
+		
+		/* If that worked, return the string. */
+		if (n > -1 && n < size)
+			return p;
+		
+		/* Else try again with more space. */
+		if (n > -1) {       /* glibc 2.1 */
+			size = n+1; /* precisely what is needed */
+		} else {            /* glibc 2.0 */
+			size *= 2;  /* twice the old size */
+		}
+		if ((np = realloc (p, size)) == NULL) {
+			free(p);
+			return NULL;
+		} else {
+			p = np;
+		}
+	}
+	
+	/* Should never get here. */
+	return p;
+}
+
 #ifdef MEM_DEBUG
 /*
  * ((destructor)) attribute executes this function after main().
diff --git a/src/common/mempattern.h b/src/common/mempattern.h
index ae1fa78..ebfe4ae 100644
--- a/src/common/mempattern.h
+++ b/src/common/mempattern.h
@@ -54,6 +54,16 @@
  */
 int mreserve(char **p, size_t tlen, size_t min, size_t allow, size_t *reserved);
 
+/*!
+ * \brief Format string and take care of allocating memory.
+ *
+ * \note sprintf(3) manual page reference implementation.
+ *
+ * \param fmt Message format.
+ * \return formatted message or NULL.
+ */
+char* sprintf_alloc(const char *fmt, ...);
+
 /*! \brief Print usage statistics.
  *
  *  \note This function has destructor attribute set if MEM_DEBUG is enabled.
diff --git a/src/config.h.in b/src/config.h.in
index b711d4f..bc3eb0e 100644
--- a/src/config.h.in
+++ b/src/config.h.in
@@ -195,6 +195,9 @@
 /* Define to 1 if you have the <sys/param.h> header file. */
 #undef HAVE_SYS_PARAM_H
 
+/* Define to 1 if you have the <sys/select.h> header file. */
+#undef HAVE_SYS_SELECT_H
+
 /* Define to 1 if you have the <sys/socket.h> header file. */
 #undef HAVE_SYS_SOCKET_H
 
@@ -207,6 +210,9 @@
 /* Define to 1 if you have the <sys/types.h> header file. */
 #undef HAVE_SYS_TYPES_H
 
+/* Define to 1 if you have the <sys/wait.h> header file. */
+#undef HAVE_SYS_WAIT_H
+
 /* Define to 1 if you have the <unistd.h> header file. */
 #undef HAVE_UNISTD_H
 
diff --git a/src/knot.conf.5 b/src/knot.conf.5
index 62954e3..f99739c 100644
--- a/src/knot.conf.5
+++ b/src/knot.conf.5
@@ -1,4 +1,4 @@
-.TH "knot.conf" "5" "September 2012" "CZ.NIC Labs" "Knot DNS, version 1.1.3"
+.TH "knot.conf" "5" "September 2012" "CZ.NIC Labs" "Knot DNS, version 1.2-rc2"
 .SH "NAME"
 .LP
 .B knot.conf
@@ -11,21 +11,27 @@
 serves as an example of the configuration for knotc(8) and knotd(8).
 .SH "EXAMPLE"
 .LP
-# This is a comment.
+ #
+ # knot.sample.conf
+ #
+ # This is a sample configuration file for Knot DNS server.
+ #
 
-#
-# There are 4 main sections of this config file:
-#   system, zones, interfaces and log
-#
+ # This is a comment.
 
-# Section 'system' contains general options for the server
-system {
+ #
+ # There are 5 main sections of this config file:
+ #   system, zones, interfaces, control and log
+ #
+
+ # Section 'system' contains general options for the server
+ system {
 
   # Identity of the server (see RFC 4892). Not used yet.
   identity "I have no mouth and must scream";
 
   # Version of the server (see RFC 4892). Not used yet.
-  version "0.1";
+  version "1.2;
 
   # Server identifier 
   # Use string format "text"
@@ -43,15 +49,34 @@ system {
   # Number of workers per interface
   # This option is used to force number of threads used per interface
   # Default: unset (auto-estimates optimal value from the number of online CPUs)
-  # workers 1;
+  # workers 3;
 
   # User for running server
-  # May also specify user.group (f.e. knot.users)
+  # May also specify user.group (e.g. knot.users)
   # user knot.users;
-}
 
-# Section 'keys' contains list of TSIG keys
-keys {
+  # Maximum idle time between requests on a TCP connection
+  # It is also possible to suffix with unit size [s/m/h/d]
+  # f.e. 1s = 1 second, 1m = 1 minute, 1h = 1 hour, 1d = 1 day
+  # Default: 60s
+  max-conn-idle 60s;
+
+  # Maximum time between newly accepted TCP connection and first query
+  # This is useful to disconnect inactive connections faster
+  # It is also possible to suffix with unit size [s/m/h/d]
+  # f.e. 1s = 1 second, 1m = 1 minute, 1h = 1 hour, 1d = 1 day
+  # Default: 10s
+  max-conn-handshake 10s;
+
+  # Maximum time to wait for a reply to SOA query
+  # It is also possible to suffix with unit size [s/m/h/d]
+  # f.e. 1s = 1 second, 1m = 1 minute, 1h = 1 hour, 1d = 1 day
+  # Default: 10s
+  max-conn-reply 10s;
+ }
+
+ # Section 'keys' contains list of TSIG keys
+ keys {
 
   # TSIG key
   #
@@ -68,10 +93,10 @@ keys {
 
   # TSIG key for zone
   key0.example.com hmac-md5 "==gW";
-}
+ }
 
-# Section 'interfaces' contains definitions of listening interfaces.
-interfaces {
+ # Section 'interfaces' contains definitions of listening interfaces.
+ interfaces {
 
   # Interface entry
   # 
@@ -96,11 +121,11 @@ interfaces {
   #   address [::1]@53534;
   # }
 
-}
+ }
 
-# Section 'remotes' contains symbolic names for remote servers.
-# Syntax for 'remotes' is the same as for 'interfaces'.
-remotes {
+ # Section 'remotes' contains symbolic names for remote servers.
+ # Syntax for 'remotes' is the same as for 'interfaces'.
+ remotes {
 
   # Remote entry
   #
@@ -118,15 +143,30 @@ remotes {
   server1 {
     address 127.0.0.1@53001;
   }
-}
+ }
+
+ # Section 'control' specifies on which interface to listen for RC commands
+ control {
+
+  # Specifies interface, syntax is exactly the same as in 'interfaces' section
+  # Note: as of now, it is possible replay commands in a short time frame
+  #       with MitM type attacks, so you should keep the interface on localnet.
+  # Default port is: 5553
+  listen-on { address 127.0.0.1@5553; }
+  
+  # Specifies ACL list for remote control
+  # Same syntax as for ACLs in zones
+  # List of remotes delimited by comma
+  allow server0;
+ }
 
-# Section 'zones' contains information about zones to be served.
-zones {
+ # Section 'zones' contains information about zones to be served.
+ zones {
 
   # Shared options for all listed zones
   #
 
-  # Build differences from zone file changes
+  # Build differences from zone file changes. EXPERIMENTAL feature.
   # Possible values: on|off
   # Default value: off
   ixfr-from-differences off;
@@ -203,7 +243,7 @@ zones {
     # Possible values: <1..INT_MAX> (seconds)
     # Default value: inherited from zones.zonefile-sync
     # It is also possible to suffix with unit size [s/m/h/d]
-    # f.e. 1s = 1 day, 1m = 1 minute, 1h = 1 hour, 1d = 1 day
+    # f.e. 1s = 1 second, 1m = 1 minute, 1h = 1 hour, 1d = 1 day
     zonefile-sync 1h;
 
     # XFR master server 
@@ -217,48 +257,51 @@ zones {
 
     # List of servers to send NOTIFY to 
     notify-out server0, server1;
+
+    # List of servers to allow UPDATE queries
+    update-in server0;
   }
-}
-
-# Section 'log' configures logging of server messages.
-#
-# Logging recognizes 3 symbolic names of log devices: 
-#   stdout    - Standard output
-#   stderr    - Standard error output
-#   syslog    - Syslog
-# 
-# In addition, arbitrary number of log files may be specified (see below).
-#
-# Log messages are characterized by severity and category.
-# Supported severities: 
-#   debug     - Debug messages. Must be turned on at compile time.
-#   info      - Informational messages.
-#   notice    - Notices and hints.
-#   warning   - Warnings. An action from the operator may be required.
-#   error     - Recoverable error. Some action should be taken.
-#   fatal     - Non-recoverable errors resulting in server shutdown.
-#               (Not supported yet.)
-#   all       - All severities.
-#
-# Categories designate the source of the log message and roughly correspond
-#   to server modules
-# Supported categories:
-#   server    - Messages related to general operation of the server.
-#   zone      - Messages related to zones, zone parsing and loading.
-#   answering - Messages regarding query processing and response creation.
-#   any       - All categories
-#
-# More severities (separated by commas) may be listed for each category.
-# All applicable severities must be listed. 
-#   (I.e. specifying 'error' severity does mean: 'log error messages', 
-#    and NOT 'log all messages of severity error and above'.)
-#
-# Default settings (in case there are no entries in 'log' section or the section
-# is missing at all):
-#
-# stderr { any error; }
-# syslog { any error; }
-log {
+ }
+
+ # Section 'log' configures logging of server messages.
+ #
+ # Logging recognizes 3 symbolic names of log devices: 
+ #   stdout    - Standard output
+ #   stderr    - Standard error output
+ #   syslog    - Syslog
+ # 
+ # In addition, arbitrary number of log files may be specified (see below).
+ #
+ # Log messages are characterized by severity and category.
+ # Supported severities: 
+ #   debug     - Debug messages. Must be turned on at compile time.
+ #   info      - Informational messages.
+ #   notice    - Notices and hints.
+ #   warning   - Warnings. An action from the operator may be required.
+ #   error     - Recoverable error. Some action should be taken.
+ #   fatal     - Non-recoverable errors resulting in server shutdown.
+ #               (Not supported yet.)
+ #   all       - All severities.
+ #
+ # Categories designate the source of the log message and roughly correspond
+ #   to server modules
+ # Supported categories:
+ #   server    - Messages related to general operation of the server.
+ #   zone      - Messages related to zones, zone parsing and loading.
+ #   answering - Messages regarding query processing and response creation.
+ #   any       - All categories
+ #
+ # More severities (separated by commas) may be listed for each category.
+ # All applicable severities must be listed. 
+ #   (I.e. specifying 'error' severity does mean: 'log error messages', 
+ #    and NOT 'log all messages of severity error and above'.)
+ #
+ # Default settings (in case there are no entries in 'log' section or the section
+ # is missing at all):
+ #
+ # stderr { any error; }
+ # syslog { any error; }
+ log {
 
   # Log entry
   #
@@ -290,7 +333,8 @@ log {
   file "/tmp/knot-sample/knotd.debug" {  # <path> is absolute or relative path to log file
     server debug;
   }
-}
+ }
+
 .SH "SEE ALSO"
 .LP
 knotd(8), knotc(8)
diff --git a/src/knot/conf/cf-lex.l b/src/knot/conf/cf-lex.l
index 58d1f4b..4be9405 100644
--- a/src/knot/conf/cf-lex.l
+++ b/src/knot/conf/cf-lex.l
@@ -68,7 +68,7 @@ BLANK [ \t\n]
 [\!\$\%\^\&\*\(\)\/\+\-\@\{\}\;\,] { return yytext[0]; }
 system          { lval.t = yytext;  return SYSTEM; }
 identity        { lval.t = yytext; return IDENTITY; }
-version         { lval.t = yytext; return VERSION; }
+version         { lval.t = yytext; return SVERSION; }
 nsid            { lval.t = yytext; return NSID; }
 storage         { lval.t = yytext; return STORAGE; }
 key             { lval.t = yytext; return KEY; }
@@ -85,18 +85,26 @@ zonefile-sync   { lval.t = yytext; return DBSYNC_TIMEOUT; }
 ixfr-fslimit    { lval.t = yytext; return IXFR_FSLIMIT; }
 xfr-in          { lval.t = yytext; return XFR_IN; }
 xfr-out         { lval.t = yytext; return XFR_OUT; }
+update-in       { lval.t = yytext; return UPDATE_IN; }
 notify-in       { lval.t = yytext; return NOTIFY_IN; }
 notify-out      { lval.t = yytext; return NOTIFY_OUT; }
 workers         { lval.t = yytext; return WORKERS; }
 user            { lval.t = yytext; return USER; }
 pidfile         { lval.t = yytext; return PIDFILE; }
 ixfr-from-differences { lval.t = yytext; return BUILD_DIFFS; }
+max-conn-idle   { lval.t = yytext; return MAX_CONN_IDLE; }
+max-conn-handshake { lval.t = yytext; return MAX_CONN_HS; }
+max-conn-reply  { lval.t = yytext; return MAX_CONN_REPLY; }
 
 interfaces      { lval.t = yytext; return INTERFACES; }
 address         { lval.t = yytext; return ADDRESS; }
 port            { lval.t = yytext; return PORT; }
 via             { lval.t = yytext; return VIA; }
 
+control         { lval.t = yytext; return CONTROL; }
+allow           { lval.t = yytext; return ALLOW; }
+listen-on       { lval.t = yytext; return LISTEN_ON; }
+
 log             { lval.t = yytext; return LOG; }
 
 any { lval.t = yytext; lval.i = LOG_ANY; return LOG_SRC; }
diff --git a/src/knot/conf/cf-parse.y b/src/knot/conf/cf-parse.y
index 4f490b5..a0c6aaf 100644
--- a/src/knot/conf/cf-parse.y
+++ b/src/knot/conf/cf-parse.y
@@ -28,7 +28,7 @@ static conf_log_t *this_log = 0;
 static conf_log_map_t *this_logmap = 0;
 //#define YYERROR_VERBOSE 1
 
-static void conf_start_iface(void *scanner, char* ifname)
+static void conf_init_iface(void *scanner, char* ifname, int port)
 {
    this_iface = malloc(sizeof(conf_iface_t));
    if (this_iface == NULL) {
@@ -37,7 +37,12 @@ static void conf_start_iface(void *scanner, char* ifname)
    }
    memset(this_iface, 0, sizeof(conf_iface_t));
    this_iface->name = ifname;
-   this_iface->port = CONFIG_DEFAULT_PORT;
+   this_iface->port = port;
+}
+
+static void conf_start_iface(void *scanner, char* ifname)
+{
+   conf_init_iface(scanner, ifname, -1);
    add_tail(&new_config->ifaces, &this_iface->n);
    ++new_config->ifaces_count;
 }
@@ -49,6 +54,7 @@ static void conf_start_remote(void *scanner, char *remote)
       cf_error(scanner, "not enough memory when allocating remote");
       return;
    }
+   
    memset(this_remote, 0, sizeof(conf_iface_t));
    this_remote->name = remote;
    add_tail(&new_config->remotes, &this_remote->n);
@@ -181,7 +187,7 @@ static void conf_zone_start(void *scanner, char *name) {
       if (this_zone->name != NULL) {
 	memcpy(this_zone->name, name, nlen);
 	this_zone->name[nlen] = '.';
-	this_zone->name[nlen + 1] = '\0';
+	this_zone->name[++nlen] = '\0';
      }
      free(name);
    } else {
@@ -192,7 +198,7 @@ static void conf_zone_start(void *scanner, char *name) {
    char buf[512];
    knot_dname_t *dn = NULL;
    if (this_zone->name != NULL) {
-      dn = knot_dname_new_from_str(this_zone->name, nlen + 1, 0);
+      dn = knot_dname_new_from_str(this_zone->name, nlen, 0);
    }
    if (dn == NULL) {
      free(this_zone->name);
@@ -224,6 +230,7 @@ static void conf_zone_start(void *scanner, char *name) {
      init_list(&this_zone->acl.xfr_out);
      init_list(&this_zone->acl.notify_in);
      init_list(&this_zone->acl.notify_out);
+     init_list(&this_zone->acl.update_in);
    }
 }
 
@@ -263,7 +270,7 @@ static int conf_mask(void* scanner, int nval, int prefixlen) {
 %token <tok> SIZE
 %token <tok> BOOL
 
-%token <tok> SYSTEM IDENTITY VERSION NSID STORAGE KEY KEYS
+%token <tok> SYSTEM IDENTITY SVERSION NSID STORAGE KEY KEYS
 %token <tok> TSIG_ALGO_NAME
 %token <tok> WORKERS
 %token <tok> USER
@@ -280,15 +287,21 @@ static int conf_mask(void* scanner, int nval, int prefixlen) {
 %token <tok> IXFR_FSLIMIT
 %token <tok> XFR_IN
 %token <tok> XFR_OUT
+%token <tok> UPDATE_IN
 %token <tok> NOTIFY_IN
 %token <tok> NOTIFY_OUT
 %token <tok> BUILD_DIFFS
+%token <tok> MAX_CONN_IDLE
+%token <tok> MAX_CONN_HS
+%token <tok> MAX_CONN_REPLY
 
 %token <tok> INTERFACES ADDRESS PORT
 %token <tok> IPA
 %token <tok> IPA6
 %token <tok> VIA
 
+%token <tok> CONTROL ALLOW LISTEN_ON
+
 %token <tok> LOG
 %token <tok> LOG_DEST
 %token <tok> LOG_SRC
@@ -309,12 +322,12 @@ interface_start:
  | LOG_SRC  { conf_start_iface(scanner, strdup($1.t)); }
  | LOG  { conf_start_iface(scanner, strdup($1.t)); }
  | LOG_LEVEL  { conf_start_iface(scanner, strdup($1.t)); }
+ | CONTROL    { conf_start_iface(scanner, strdup($1.t)); }
  ;
 
 interface:
-   interface_start '{'
  | interface PORT NUM ';' {
-     if (this_iface->port != CONFIG_DEFAULT_PORT) {
+     if (this_iface->port > 0) {
        cf_error(scanner, "only one port definition is allowed in interface section\n");
      } else {
        this_iface->port = $3.i;
@@ -334,7 +347,7 @@ interface:
      } else {
        this_iface->address = $3.t;
        this_iface->family = AF_INET;
-       if (this_iface->port != CONFIG_DEFAULT_PORT) {
+       if (this_iface->port > 0) {
 	 cf_error(scanner, "only one port definition is allowed in interface section\n");
        } else {
 	 this_iface->port = $5.i;
@@ -355,7 +368,7 @@ interface:
      } else {
        this_iface->address = $3.t;
        this_iface->family = AF_INET6;
-       if (this_iface->port != CONFIG_DEFAULT_PORT) {
+       if (this_iface->port > 0) {
           cf_error(scanner, "only one port definition is allowed in interface section\n");
        } else {
           this_iface->port = $5.i;
@@ -366,7 +379,7 @@ interface:
 
 interfaces:
    INTERFACES '{'
- | interfaces interface '}' {
+ | interfaces interface_start '{' interface '}' {
    if (this_iface->address == 0) {
      char buf[512];
      snprintf(buf, sizeof(buf), "interface '%s' has no defined address", this_iface->name);
@@ -377,7 +390,7 @@ interfaces:
 
 system:
    SYSTEM '{'
- | system VERSION TEXT ';' { new_config->version = $3.t; }
+ | system SVERSION TEXT ';' { new_config->version = $3.t; }
  | system IDENTITY TEXT ';' { new_config->identity = $3.t; }
  | system NSID HEXSTR ';' { new_config->nsid = $3.t; new_config->nsid_len = $3.l; }
  | system NSID TEXT ';' { new_config->nsid = $3.t; new_config->nsid_len = strlen(new_config->nsid); }
@@ -419,6 +432,9 @@ system:
      
      free($3.t);
  }
+ | system MAX_CONN_IDLE INTERVAL ';' { new_config->max_conn_idle = $3.i; }
+ | system MAX_CONN_HS INTERVAL ';' { new_config->max_conn_hs = $3.i; }
+ | system MAX_CONN_REPLY INTERVAL ';' { new_config->max_conn_reply = $3.i; }
  ;
 
 keys:
@@ -478,10 +494,10 @@ remote_start:
  | LOG_SRC  { conf_start_remote(scanner, strdup($1.t)); }
  | LOG  { conf_start_remote(scanner, strdup($1.t)); }
  | LOG_LEVEL  { conf_start_remote(scanner, strdup($1.t)); }
+ | CONTROL    { conf_start_remote(scanner, strdup($1.t)); }
  ;
 
 remote:
-   remote_start '{'
  | remote PORT NUM ';' {
      if (this_remote->port != 0) {
        cf_error(scanner, "only one port definition is allowed in remote section\n");
@@ -577,7 +593,7 @@ remote:
 
 remotes:
    REMOTES '{'
- | remotes remote '}' {
+ | remotes remote_start '{' remote '}' {
      if (this_remote->address == 0) {
        char buf[512];
        snprintf(buf, sizeof(buf), "remote '%s' has no defined address", this_remote->name);
@@ -599,6 +615,9 @@ zone_acl_start:
  | NOTIFY_OUT {
       this_list = &this_zone->acl.notify_out;
    }
+ | UPDATE_IN {
+      this_list = &this_zone->acl.update_in;
+ }
  ;
 
 zone_acl_item:
@@ -606,16 +625,15 @@ zone_acl_item:
  | LOG_SRC  { conf_acl_item(scanner, strdup($1.t)); }
  | LOG  { conf_acl_item(scanner, strdup($1.t)); }
  | LOG_LEVEL  { conf_acl_item(scanner, strdup($1.t)); }
+ | CONTROL    { conf_acl_item(scanner, strdup($1.t)); }
  ;
 
 zone_acl_list:
-   zone_acl_start
  | zone_acl_list zone_acl_item ','
  | zone_acl_list zone_acl_item ';'
  ;
 
 zone_acl:
-   zone_acl_start '{'
  | zone_acl TEXT ';' {
       /* Find existing node in remotes. */
       node* r = 0; conf_iface_t* found = 0;
@@ -652,6 +670,7 @@ zone_start:
  | LOG_SRC { conf_zone_start(scanner, strdup($1.t)); }
  | LOG { conf_zone_start(scanner, strdup($1.t)); }
  | LOG_LEVEL { conf_zone_start(scanner, strdup($1.t)); }
+ | CONTROL    { conf_zone_start(scanner, strdup($1.t)); }
  | NUM '/' TEXT {
     if ($1.i < 0 || $1.i > 255) {
         char buf[256] = "";
@@ -676,8 +695,8 @@ zone_start:
 
 zone:
    zone_start '{'
- | zone zone_acl '}'
- | zone zone_acl_list
+ | zone zone_acl_start '{' zone_acl '}'
+ | zone zone_acl_start zone_acl_list
  | zone FILENAME TEXT ';' { this_zone->file = $3.t; }
  | zone BUILD_DIFFS BOOL ';' { this_zone->build_diffs = $3.i; }
  | zone SEMANTIC_CHECKS BOOL ';' { this_zone->enable_checks = $3.i; }
@@ -816,8 +835,30 @@ log_start:
 
 log: LOG '{' log_start log_end;
 
+ctl_listen_start:
+  LISTEN_ON { conf_init_iface(scanner, NULL, -1); }
+  ;
+
+ctl_allow_start:
+  ALLOW {
+    this_list = &new_config->ctl.allow;
+  }
+  ;
+
+control:
+   CONTROL '{'
+ | control ctl_listen_start '{' interface '}' {
+     if (this_iface->address == 0) {
+       cf_error(scanner, "control interface has no defined address");
+     } else {
+       new_config->ctl.iface = this_iface;
+     }
+ }
+ | control ctl_allow_start '{' zone_acl '}'
+ | control ctl_allow_start zone_acl_list
+ ; 
 
-conf: ';' | system '}' | interfaces '}' | keys '}' | remotes '}' | zones '}' | log '}';
+conf: ';' | system '}' | interfaces '}' | keys '}' | remotes '}' | zones '}' | log '}' | control '}';
 
 %%
 
diff --git a/src/knot/conf/conf.c b/src/knot/conf/conf.c
index d9d0a77..ac36670 100644
--- a/src/knot/conf/conf.c
+++ b/src/knot/conf/conf.c
@@ -26,6 +26,7 @@
 #include <urcu.h>
 #include "knot/conf/conf.h"
 #include "knot/common.h"
+#include "knot/ctl/remote.h"
 
 /*
  * Defaults.
@@ -158,6 +159,28 @@ static int conf_process(conf_t *conf)
 			return KNOT_ENOMEM;
 		}
 	}
+	
+	/* Default TCP/UDP limits. */
+	if (conf->max_conn_idle < 1) {
+		conf->max_conn_idle = CONFIG_IDLE_WD;
+	}
+	if (conf->max_conn_hs < 1) {
+		conf->max_conn_hs = CONFIG_HANDSHAKE_WD;
+	}
+	if (conf->max_conn_reply < 1) {
+		conf->max_conn_reply = CONFIG_REPLY_WD;
+	}
+	
+	// Postprocess interfaces
+	conf_iface_t *cfg_if = NULL;
+	WALK_LIST(cfg_if, conf->ifaces) {
+		if (cfg_if->port <= 0) {
+			cfg_if->port = CONFIG_DEFAULT_PORT;
+		}
+	}
+	if (conf->ctl.iface && conf->ctl.iface->port <= 0) {
+		conf->ctl.iface->port = REMOTE_DPORT;
+	}
 
 	// Postprocess zones
 	int ret = KNOT_EOK;
@@ -289,6 +312,17 @@ static int conf_process(conf_t *conf)
 	/* Update UID and GID. */
 	if (conf->uid < 0) conf->uid = getuid();
 	if (conf->gid < 0) conf->gid = getgid();
+	
+	/* Build remote control ACL. */
+	sockaddr_t addr;
+	conf_remote_t *r = NULL;
+	WALK_LIST(r, conf->ctl.allow) {
+		conf_iface_t *i = r->remote;
+		sockaddr_init(&addr, -1);
+		sockaddr_set(&addr, i->family, i->address, 0);
+		sockaddr_setprefix(&addr, i->prefix);
+		acl_create(conf->ctl.acl, &addr, ACL_ACCEPT, i, 0);
+	}
 
 	return ret;
 }
@@ -304,6 +338,9 @@ void __attribute__ ((constructor)) conf_init()
 {
 	// Create new config
 	s_config = conf_new(0);
+	if (!s_config) {
+		return;
+	}
 
 	/* Create default interface. */
 	conf_iface_t * iface = malloc(sizeof(conf_iface_t));
@@ -436,20 +473,21 @@ conf_t *conf_new(const char* path)
 	conf_t *c = malloc(sizeof(conf_t));
 	memset(c, 0, sizeof(conf_t));
 
-	// Add path
+	/* Add path. */
 	if (path) {
 		c->filename = strdup(path);
 	}
 
-	// Initialize lists
+	/* Initialize lists. */
 	init_list(&c->logs);
 	init_list(&c->ifaces);
 	init_list(&c->zones);
 	init_list(&c->hooks);
 	init_list(&c->remotes);
 	init_list(&c->keys);
+	init_list(&c->ctl.allow);
 
-	// Defaults
+	/* Defaults. */
 	c->zone_checks = 0;
 	c->notify_retries = CONFIG_NOTIFY_RETRIES;
 	c->notify_timeout = CONFIG_NOTIFY_TIMEOUT;
@@ -458,6 +496,14 @@ conf_t *conf_new(const char* path)
 	c->uid = -1;
 	c->gid = -1;
 	c->build_diffs = 0; /* Disable by default. */
+	
+	/* ACLs. */
+	c->ctl.acl = acl_new(ACL_DENY, "remote_ctl");
+	if (!c->ctl.acl) {
+		free(c->filename);
+		free(c);
+		c = NULL;
+	}
 
 	return c;
 }
@@ -557,7 +603,7 @@ void conf_truncate(conf_t *conf, int unload_hooks)
 	conf->logs_count = 0;
 	init_list(&conf->logs);
 
-	// Free remotes
+	// Free remote interfaces
 	WALK_LIST_DELSAFE(n, nxt, conf->remotes) {
 		conf_free_iface((conf_iface_t*)n);
 	}
@@ -595,6 +641,19 @@ void conf_truncate(conf_t *conf, int unload_hooks)
 		free(conf->nsid);
 		conf->nsid = 0;
 	}
+	
+	/* Free remote control list. */
+	WALK_LIST_DELSAFE(n, nxt, conf->ctl.allow) {
+		conf_free_remote((conf_remote_t*)n);
+	}
+	conf->remotes_count = 0;
+	init_list(&conf->remotes);
+	
+	/* Free remote control ACL. */
+	acl_truncate(conf->ctl.acl);
+	
+	/* Free remote control iface. */
+	conf_free_iface(conf->ctl.iface);
 }
 
 void conf_free(conf_t *conf)
@@ -603,10 +662,13 @@ void conf_free(conf_t *conf)
 		return;
 	}
 
-	// Truncate config
+	/* Truncate config. */
 	conf_truncate(conf, 1);
+	
+	/* Free remote control ACL. */
+	acl_delete(&conf->ctl.acl);
 
-	// Free config
+	/* Free config. */
 	free(conf);
 }
 
@@ -653,6 +715,9 @@ int conf_open(const char* path)
 
 	/* Create new config. */
 	conf_t *nconf = conf_new(path);
+	if (!nconf) {
+		return KNOT_ENOMEM;
+	}
 
 	/* Parse config. */
 	conf_parse_begin(nconf);
@@ -784,6 +849,7 @@ void conf_free_zone(conf_zone_t *zone)
 	WALK_LIST_FREE(zone->acl.xfr_out);
 	WALK_LIST_FREE(zone->acl.notify_in);
 	WALK_LIST_FREE(zone->acl.notify_out);
+	WALK_LIST_FREE(zone->acl.update_in);
 
 	free(zone->name);
 	free(zone->file);
@@ -814,6 +880,11 @@ void conf_free_iface(conf_iface_t *iface)
 	free(iface);
 }
 
+void conf_free_remote(conf_remote_t *r)
+{
+	free(r);
+}
+
 void conf_free_log(conf_log_t *log)
 {
 	if (!log) {
diff --git a/src/knot/conf/conf.h b/src/knot/conf/conf.h
index 9f2440e..a64388e 100644
--- a/src/knot/conf/conf.h
+++ b/src/knot/conf/conf.h
@@ -38,6 +38,7 @@
 #include "libknot/tsig.h"
 #include "common/lists.h"
 #include "common/log.h"
+#include "common/acl.h"
 #include "common/sockaddr.h"
 #include "common/general-tree.h"
 
@@ -46,6 +47,9 @@
 #define CONFIG_NOTIFY_RETRIES 5  /*!< 5 retries (suggested in RFC1996) */
 #define CONFIG_NOTIFY_TIMEOUT 60 /*!< 60s (suggested in RFC1996) */
 #define CONFIG_DBSYNC_TIMEOUT (60*60) /*!< 1 hour. */
+#define CONFIG_REPLY_WD 10 /*!< SOA/NOTIFY query timeout [s]. */
+#define CONFIG_HANDSHAKE_WD 10 /*!< [secs] for connection to make a request.*/
+#define CONFIG_IDLE_WD  60 /*!< [secs] of allowed inactivity between requests */
 
 /*!
  * \brief Configuration for the interface
@@ -103,6 +107,7 @@ typedef struct conf_zone_t {
 		list xfr_out;     /*!< Remotes accepted for xfr-out.*/
 		list notify_in;   /*!< Remotes accepted for notify-in.*/
 		list notify_out;  /*!< Remotes accepted for notify-out.*/
+		list update_in;  /*!< Remotes accepted for DDNS.*/
 	} acl;
 } conf_zone_t;
 
@@ -145,6 +150,15 @@ typedef struct conf_key_t {
 } conf_key_t;
 
 /*!
+ * \brief Remote control interface.
+ */
+typedef struct conf_control_t {
+	conf_iface_t *iface; /*!< Remote control interface. */
+	list allow;          /*!< List of allowed remotes. */
+	acl_t* acl;          /*!< ACL. */
+} conf_control_t;
+
+/*!
  * \brief Main config structure.
  *
  * Configuration structure.
@@ -163,6 +177,9 @@ typedef struct conf_t {
 	int   workers;  /*!< Number of workers per interface. */
 	int   uid;      /*!< Specified user id. */
 	int   gid;      /*!< Specified group id. */
+	int   max_conn_idle; /*!< TCP idle timeout. */
+	int   max_conn_hs;   /*!< TCP of inactivity before first query. */
+	int   max_conn_reply; /*!< TCP/UDP query timeout. */
 
 	/*
 	 * Log
@@ -203,6 +220,11 @@ typedef struct conf_t {
 	general_tree_t *zone_tree; /*!< Zone tree for duplicate checking. */
 	
 	/*
+	 * Remote control interface.
+	 */
+	conf_control_t ctl;
+
+	/*
 	 * Implementation specifics
 	 */
 	list hooks;      /*!< List of config hooks. */
@@ -360,6 +382,9 @@ void conf_free_key(conf_key_t *k);
 /*! \brief Free interface config. */
 void conf_free_iface(conf_iface_t *iface);
 
+/*! \brief Free remotes config. */
+void conf_free_remote(conf_remote_t *r);
+
 /*! \brief Free log config. */
 void conf_free_log(conf_log_t *log);
 
diff --git a/src/knot/ctl/knotc_main.c b/src/knot/ctl/knotc_main.c
index dd9a8e7..92c5c09 100644
--- a/src/knot/ctl/knotc_main.c
+++ b/src/knot/ctl/knotc_main.c
@@ -12,73 +12,124 @@
 
     You should have received a copy of the GNU General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
+*/
 
 #include <config.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <string.h>
-#include <sys/wait.h>
 #include <time.h>
-#include <sys/select.h>
-#include <sys/stat.h>
 #include <getopt.h>
+#include <ctype.h>
+#ifdef HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+#ifdef HAVE_SYS_SELECT_H
+#include <sys/select.h>
+#endif
+#ifdef HAVE_SYS_WAIT_H
+#include <sys/wait.h>
+#endif
 
 #include "knot/common.h"
 #include "knot/ctl/process.h"
+#include "knot/ctl/remote.h"
 #include "knot/conf/conf.h"
 #include "knot/zone/zone-load.h"
+#include "knot/server/socket.h"
+#include "knot/server/tcp-handler.h"
+#include "libknot/util/wire.h"
+#include "libknot/packet/query.h"
+#include "libknot/packet/response.h"
 
 /*! \brief Controller constants. */
 enum knotc_constants_t {
-	WAITPID_TIMEOUT = 10 /*!< \brief Timeout for waiting for process. */
+	WAITPID_TIMEOUT = 120   /*!< \brief Timeout for waiting for process. */
 };
 
 /*! \brief Controller flags. */
 enum knotc_flag_t {
-	F_NULL        = 0 << 0,
-	F_FORCE       = 1 << 0,
-	F_VERBOSE     = 1 << 1,
-	F_WAIT        = 1 << 2,
+	F_NULL = 0 << 0,
+	F_FORCE = 1 << 0,
+	F_VERBOSE = 1 << 1,
+	F_WAIT = 1 << 2,
 	F_INTERACTIVE = 1 << 3,
-	F_AUTO        = 1 << 4,
-	F_UNPRIVILEGED= 1 << 5
+	F_AUTO = 1 << 4,
+	F_UNPRIVILEGED = 1 << 5,
+	F_NOCONF = 1 << 6,
+	F_DRYRUN = 1 << 7
 };
 
-static inline unsigned has_flag(unsigned flags, enum knotc_flag_t f) {
+/*! \brief Check if flag is present. */
+static inline unsigned has_flag(unsigned flags, enum knotc_flag_t f)
+{
 	return flags & f;
 }
 
+/*! \brief Callback prototype for command. */
+typedef int (*knot_cmdf_t)(int argc, char *argv[], unsigned flags, int jobs);
+
+/*! \brief Command table item. */
+typedef struct knot_cmd_t {
+	const char *name;
+	knot_cmdf_t cb;
+	const char *desc;
+	int need_conf;
+} knot_cmd_t;
+
+/* Forward decls. */
+static int cmd_start(int argc, char *argv[], unsigned flags, int jobs);
+static int cmd_stop(int argc, char *argv[], unsigned flags, int jobs);
+static int cmd_restart(int argc, char *argv[], unsigned flags, int jobs);
+static int cmd_reload(int argc, char *argv[], unsigned flags, int jobs);
+static int cmd_refresh(int argc, char *argv[], unsigned flags, int jobs);
+static int cmd_flush(int argc, char *argv[], unsigned flags, int jobs);
+static int cmd_status(int argc, char *argv[], unsigned flags, int jobs);
+static int cmd_checkconf(int argc, char *argv[], unsigned flags, int jobs);
+static int cmd_checkzone(int argc, char *argv[], unsigned flags, int jobs);
+static int cmd_compile(int argc, char *argv[], unsigned flags, int jobs);
+
+/*! \brief Table of remote commands. */
+knot_cmd_t knot_cmd_tbl[] = {
+	{"start",     &cmd_start, "\tStart server (no-op if running).", 1},
+	{"stop",      &cmd_stop, "\tStop server (no-op if running).", 1},
+	{"restart",   &cmd_restart, "Restarts server (no-op if running).", 1},
+	{"reload",    &cmd_reload, "\tReloads configuration and changed zones.",0},
+	{"refresh",   &cmd_refresh,"Refresh slave zones (all if not specified).",0},
+	{"flush",     &cmd_flush, "\tFlush journal and update zone files.",0},
+	{"status",    &cmd_status, "\tCheck if server is running.",0},
+	{"checkconf", &cmd_checkconf, "Check server configuration.",1},
+	{"checkzone", &cmd_checkzone, "Check specified zone files.",1},
+	{"compile",   &cmd_compile, "Compile zone files (all if not specified).",1},
+	{NULL, NULL, NULL,0}
+};
+
 /*! \brief Print help. */
 void help(int argc, char **argv)
 {
-	printf("Usage: %sc [parameters] start|stop|restart|reload|running|"
-	       "compile [additional]\n", PACKAGE_NAME);
+	printf("Usage: %sc [parameters] <action> [action_args]\n", PACKAGE_NAME);
 	printf("\nParameters:\n"
-	       " -c [file], --config=[file] Select configuration file.\n"
-	       " -j [num], --jobs=[num]     Number of parallel tasks to run when compiling.\n"
-	       " -f, --force                Force operation - override some checks.\n"
-	       " -v, --verbose              Verbose mode - additional runtime information.\n"
-	       " -V, --version              Print %s server version.\n"
-	       " -w, --wait                 Wait for the server to finish start/stop operations.\n"
-	       " -i, --interactive          Interactive mode (do not daemonize).\n"
-	       " -a, --auto                 Enable automatic recompilation (start or reload).\n"
-	       " -h, --help                 Print help and usage.\n",
-	       PACKAGE_NAME);
-	printf("\nActions:\n"
-	       " start     Start %s server zone (no-op if running).\n"
-	       " stop      Stop %s server (no-op if not running).\n"
-	       " restart   Stops and then starts %s server.\n"
-	       " reload    Reload %s configuration and compiled zones.\n"
-	       " refresh   Refresh all slave zones.\n"
-	       " running   Check if server is running.\n"
-	       " checkconf Check server configuration.\n"
-	       "\n"
-	       " checkzone Check zones (accepts specific zones, \n"
-	       "           e.g. 'knotc checkzone example1.com example2.com').\n"
-	       " compile   Compile zones (accepts specific zones, see above).\n",
-	       PACKAGE_NAME, PACKAGE_NAME, PACKAGE_NAME, PACKAGE_NAME);
+	       " -c [file], --config=[file]\tSelect configuration file.\n"
+	       " -j [num], --jobs=[num]    \tNumber of parallel tasks to run when compiling.\n"
+	       " -s [server]               \tRemote server address (default %s)\n"
+	       " -p [port]                 \tRemote server port (default %d)\n"
+	       " -y [hmac:]name:key]       \tUse key_id specified on the command line.\n"
+	       " -k [file]                 \tUse key file (as in config section 'keys').\n"
+	       "                           \t  f.e. echo \"knotc-key hmac-md5 Wg==\" > knotc.key\n"
+	       " -f, --force               \tForce operation - override some checks.\n"
+	       " -v, --verbose             \tVerbose mode - additional runtime information.\n"
+	       " -V, --version             \tPrint %s server version.\n"
+	       " -w, --wait                \tWait for the server to finish start/stop operations.\n"
+	       " -i, --interactive         \tInteractive mode (do not daemonize).\n"
+	       " -h, --help                \tPrint help and usage.\n",
+	       "127.0.0.1", REMOTE_DPORT, PACKAGE_NAME);
+	printf("\nActions:\n");
+	knot_cmd_t *c = knot_cmd_tbl;
+	while (c->name != NULL) {
+		printf(" %s\t\t\t%s\n", c->name, c->desc);
+		++c;
+	}
 }
 
 /*!
@@ -90,14 +141,14 @@ void help(int argc, char **argv)
  * \retval KNOT_EOK if up to date.
  * \retval KNOT_ERROR if needs recompilation.
  */
-int check_zone(const char *db, const char* source)
+static int check_zone(const char *db, const char *source)
 {
 	/* Check zonefile. */
 	struct stat st;
 	if (stat(source, &st) != 0) {
 		int reason = errno;
 		const char *emsg = "";
-		switch(reason) {
+		switch (reason) {
 		case EACCES:
 			emsg = "Not enough permissions to access zone file '%s'.\n";
 			break;
@@ -108,7 +159,6 @@ int check_zone(const char *db, const char* source)
 			emsg = "Unable to stat zone file '%s'.\n";
 			break;
 		}
-		
 		log_zone_error(emsg, source);
 		return KNOT_ENOENT;
 	}
@@ -131,65 +181,6 @@ int check_zone(const char *db, const char* source)
 	return ret;
 }
 
-pid_t wait_cmd(pid_t proc, int *rc)
-{
-	/* Wait for finish. */
-	sigset_t newset;
-	sigfillset(&newset);
-	sigprocmask(SIG_BLOCK, &newset, 0);
-	proc = waitpid(proc, rc, 0);
-	sigprocmask(SIG_UNBLOCK, &newset, 0);
-	return proc;
-}
-
-pid_t start_cmd(const char *argv[], int argc, int flags)
-{
-	pid_t chproc = fork();
-	if (chproc == 0) {
-	
-		/* Alter privileges. */
-		if (flags & F_UNPRIVILEGED) {
-			proc_update_privileges(conf()->uid, conf()->gid);
-		}
-
-		/* Duplicate, it doesn't run from stack address anyway. */
-		char **args = malloc((argc + 1) * sizeof(char*));
-		memset(args, 0, (argc + 1) * sizeof(char*));
-		int ci = 0;
-		for (int i = 0; i < argc; ++i) {
-			if (strlen(argv[i]) > 0) {
-				args[ci++] = strdup(argv[i]);
-			}
-		}
-		args[ci] = 0;
-
-		/* Execute command. */
-		fflush(stdout);
-		fflush(stderr);
-		execvp(args[0], args);
-
-		/* Execute failed. */
-		log_server_error("Failed to run executable '%s'\n", args[0]);
-		for (int i = 0; i < argc; ++i) {
-			free(args[i]);
-		}
-		free(args);
-
-		exit(1);
-		return -1;
-	}
-	
-	return chproc;
-}
-
-int exec_cmd(const char *argv[], int argc)
-{
-	int ret = 0;
-	pid_t proc = start_cmd(argv, argc, 0);
-	wait_cmd(proc, &ret);
-	return ret;
-}
-
 /*! \brief Zone compiler task. */
 typedef struct {
 	conf_zone_t *zone;
@@ -197,44 +188,44 @@ typedef struct {
 } knotc_zctask_t;
 
 /*! \brief Create set of watched tasks. */
-knotc_zctask_t *zctask_create(int count)
+static knotc_zctask_t *zctask_create(int count)
 {
 	if (count <= 0) {
 		return 0;
 	}
-	
+
 	knotc_zctask_t *t = malloc(count * sizeof(knotc_zctask_t));
 	for (unsigned i = 0; i < count; ++i) {
 		t[i].proc = -1;
 		t[i].zone = 0;
 	}
-	
+
 	return t;
 }
 
 /*! \brief Wait for single task to finish. */
-int zctask_wait(knotc_zctask_t *tasks, int count, int is_checkzone)
+static int zctask_wait(knotc_zctask_t *tasks, int count, int is_checkzone)
 {
 	/* Wait for children to finish. */
 	int rc = 0;
-	pid_t pid = wait_cmd(-1, &rc);
+	pid_t pid = pid_wait(-1, &rc);
 	
 	/* Find task. */
 	conf_zone_t *z = 0;
 	for (unsigned i = 0; i < count; ++i) {
 		if (tasks[i].proc == pid) {
-			tasks[i].proc = -1; /* Invalidate. */
+			tasks[i].proc = -1;     /* Invalidate. */
 			z = tasks[i].zone;
 			break;
 		}
 	}
-	
+
 	if (z == 0) {
 		log_server_error("Failed to find zone for finished "
 		                 "zone compilation process.\n");
 		return 1;
 	}
-	
+
 	/* Evaluate. */
 	if (!WIFEXITED(rc)) {
 		log_server_error("%s of '%s' failed, process was killed.\n",
@@ -249,15 +240,17 @@ int zctask_wait(knotc_zctask_t *tasks, int count, int is_checkzone)
 				               "return code was '%d'\n",
 				               z->name, WEXITSTATUS(rc));
 			}
+
 			return 1;
 		}
 	}
-	
+
 	return 0;
 }
 
 /*! \brief Register running zone compilation process. */
-int zctask_add(knotc_zctask_t *tasks, int count, pid_t pid, conf_zone_t *zone)
+static int zctask_add(knotc_zctask_t *tasks, int count, pid_t pid,
+                      conf_zone_t *zone)
 {
 	/* Find free space. */
 	for (unsigned i = 0; i < count; ++i) {
@@ -267,479 +260,792 @@ int zctask_add(knotc_zctask_t *tasks, int count, pid_t pid, conf_zone_t *zone)
 			return 0;
 		}
 	}
-	
+
 	/* Free space not found. */
 	return -1;
 }
 
-/*!
- * \brief Execute specified action.
- *
- * \param action Action to be executed (start, stop, restart...)
- * \param argv Additional arguments vector.
- * \param argc Addition arguments count.
- * \param pid Specified PID for action.
- * \param verbose True if running in verbose mode.
- * \param force True if forced operation is required.
- * \param wait Wait for the operation to finish.
- * \param interactive Interactive mode.
- * \param automatic Automatic compilation.
- * \param jobs Number of parallel tasks to run.
- * \param pidfile Specified PID file for action.
- *
- * \retval 0 on success.
- * \retval error return code for main on error.
- */
-int execute(const char *action, char **argv, int argc, pid_t pid,
-            unsigned flags, unsigned jobs, const char *pidfile)
+static int cmd_remote_print_reply(const knot_rrset_t *rr)
 {
-	int valid_cmd = 0;
-	int rc = 0;
-	if (strcmp(action, "start") == 0) {
-		// Check pidfile for w+
-		log_server_info("Starting server...\n");
-
-		// Check PID
-		valid_cmd = 1;
-//		if (pid < 0 && pid == KNOT_ERANGE) {
-//			fprintf(stderr, "control: Another server instance "
-//					 "is already starting.\n");
-//			return 1;
-//		}
-		if (pid > 0 && pid_running(pid)) {
-
-			log_server_error("Server PID found, "
-			                 "already running.\n");
-
-			if (!has_flag(flags, F_FORCE)) {
-				return 1;
-			} else {
-				log_server_info("Forcing  server start, "
-				                "killing old pid=%ld.\n",
-				                (long)pid);
-				kill(pid, SIGKILL);
-				pid_remove(pidfile);
-			}
-		}
-
-		// Recompile zones if needed
-		if (has_flag(flags, F_AUTO)) {
-			rc = execute("compile", argv, argc, -1, flags,
-			             jobs, pidfile);
-		}
-
-		// Lock configuration
-		rcu_read_lock();
-
-		// Prepare command
-		const char *cfg = conf()->filename;
-		const char *args[] = {
-			PROJECT_EXEC,
-			has_flag(flags, F_INTERACTIVE) ? "" : "-d",
-			cfg ? "-c" : "",
-			cfg ? cfg : "",
-			has_flag(flags, F_VERBOSE) ? "-v" : "",
-			argc > 0 ? argv[0] : ""
-		};
-
-		// Unlock configuration
-		rcu_read_unlock();
-
-		// Execute command
-		if (has_flag(flags, F_INTERACTIVE)) {
-			log_server_info("Running in interactive mode.\n");
-			fflush(stderr);
-			fflush(stdout);
-		}
-		if ((rc = exec_cmd(args, 6)) < 0) {
-			pid_remove(pidfile);
-			rc = 1;
-		}
-		fflush(stderr);
-		fflush(stdout);
-
-		// Wait for finish
-		if (has_flag(flags, F_WAIT) && !has_flag(flags, F_INTERACTIVE)) {
-			if (has_flag(flags, F_VERBOSE)) {
-				log_server_info("Waiting for server to load.\n");
-			}
-			/* Periodically read pidfile and wait for
-			 * valid result. */
-			pid = 0;
-			while(pid == 0 || !pid_running(pid)) {
-				pid = pid_read(pidfile);
-				struct timeval tv;
-				tv.tv_sec = 0;
-				tv.tv_usec = 500 * 1000;
-				select(0, 0, 0, 0, &tv);
-			}
-		}
+	/* Process first RRSet in data section. */
+	if (knot_rrset_type(rr) != KNOT_RRTYPE_TXT) {
+		return KNOT_EMALF;
 	}
-	if (strcmp(action, "stop") == 0) {
-
-		// Check PID
-		log_server_info("Stopping server...\n");
-		valid_cmd = 1;
-		rc = 0;
-		if (pid <= 0 || !pid_running(pid)) {
-			log_server_warning("Server PID not found, "
-			                   "probably not running.\n");
-
-			if (!has_flag(flags, F_FORCE)) {
-				rc = 1;
-			} else {
-				log_server_info("Forcing server stop.\n");
-			}
+	
+	const knot_rdata_t *rd = knot_rrset_rdata(rr);
+	while (rd != NULL) {
+		/* Skip empty nodes. */
+		if (knot_rdata_item_count(rd) < 1) {
+			rd = knot_rrset_rdata_next(rr, rd);
+			continue;
 		}
 
-		// Stop
-		if (rc == 0) {
-			if (kill(pid, SIGTERM) < 0) {
-				pid_remove(pidfile);
-				rc = 1;
-			}
+		/* Parse TXT. */
+		char* txt = remote_parse_txt(rd);
+		if (txt) {
+			log_server_info("Server reply: %s\n", txt);
 		}
+		free(txt);
 
-		// Wait for finish
-		if (rc == 0 && has_flag(flags, F_WAIT)) {
-			if (has_flag(flags, F_VERBOSE)) {
-				log_server_info("Waiting for server "
-				                "to stop.\n");
-			}
-			/* Periodically read pidfile and wait for
-			 * valid result. */
-			while(pid_running(pid)) {
-				struct timeval tv;
-				tv.tv_sec = 0;
-				tv.tv_usec = 500 * 1000;
-				select(0, 0, 0, 0, &tv);
-			}
-		}
+		rd = knot_rrset_rdata_next(rr, rd);
 	}
-	if (strcmp(action, "restart") == 0) {
-		valid_cmd = 1;
-		execute("stop", argv, argc, pid, flags, jobs, pidfile);
-
-		int i = 0;
-		while((pid = pid_read(pidfile)) > 0) {
+	
+	return KNOT_EOK;
+}
 
-			if (!pid_running(pid)) {
-				pid_remove(pidfile);
-				break;
-			}
-			if (i == WAITPID_TIMEOUT) {
-				log_server_error("Timeout while  waiting for "
-				                 "the server to finish.\n");
-				//pid_remove(pidfile);
-				break;
-			} else {
-				sleep(1);
-				++i;
-			}
+static int cmd_remote_reply(int c)
+{
+	uint8_t *rwire = malloc(SOCKET_MTU_SZ);
+	knot_packet_t *reply = knot_packet_new(KNOT_PACKET_PREALLOC_RESPONSE);
+	if (!rwire || !reply) {
+		free(rwire);
+		knot_packet_free(&reply);
+		return KNOT_ENOMEM;
+	}
+	
+	/* Read response packet. */
+	int n = tcp_recv(c, rwire, SOCKET_MTU_SZ, NULL);
+	if (n < 0) {
+		dbg_server("remote: couldn't receive response = %d\n", n);
+		knot_packet_free(&reply);
+		free(rwire);
+		return KNOT_ECONN;
+	}
+	
+	/* Parse packet and check response. */
+	int ret = remote_parse(reply, rwire, n);
+	if (ret == KNOT_EOK) {
+		/* Check RCODE */
+		ret = knot_packet_rcode(reply);
+		
+		/* Check extra data. */
+		if (knot_packet_authority_rrset_count(reply) > 0) {
+			ret = cmd_remote_print_reply(reply->authority[0]);
 		}
-
-		rc = execute("start", argv, argc, -1, flags, jobs, pidfile);
 	}
-	if (strcmp(action, "reload") == 0) {
-
-		// Check PID
-		valid_cmd = 1;
-		if (pid <= 0 || !pid_running(pid)) {
-			log_server_warning("Server PID not found, "
-			                   "probably not running.\n");
+	
+	/* Response cleanup. */
+	knot_packet_free(&reply);
+	free(rwire);
+	return ret;
+}
 
-			return 1;
-		}
+static int cmd_remote(const char *cmd, uint16_t rrt, int argc, char *argv[])
+{
+	int rc = 0;
 
-		// Recompile zones if needed
-		if (has_flag(flags, F_AUTO)) {
-			rc = execute("compile", argv, argc, -1, flags,
-			             jobs, pidfile);
+	/* Check remote address. */
+	conf_iface_t *r = conf()->ctl.iface;
+	if (!r || !r->address) {
+		log_server_error("No remote address for '%s' configured.\n",
+		                 cmd);
+		return 1;
+	}
+	
+	/* Make query. */
+	uint8_t *buf = NULL;
+	size_t buflen = 0;
+	knot_packet_t *qr = remote_query(cmd, r->key);
+	if (!qr) {
+		log_server_warning("Could not prepare query for '%s'.\n",
+		                   cmd);
+		return 1;
+	}
+	
+	/* Build query data. */
+	knot_rdata_t *rd = NULL;
+	knot_rrset_t *rr = remote_build_rr("data.", rrt);
+	for (int i = 0; i < argc; ++i) {
+		switch(rrt) {
+		case KNOT_RRTYPE_CNAME:
+			rd = remote_create_cname(argv[i]);
+			break;
+		case KNOT_RRTYPE_TXT:
+		default:
+			rd = remote_create_txt(argv[i]);
+			break;
 		}
+		knot_rrset_add_rdata(rr, rd);
+		rd = NULL;
+	}
+	remote_query_append(qr, rr);
+	if (knot_packet_to_wire(qr, &buf, &buflen) != KNOT_EOK) {
+		knot_rrset_deep_free(&rr, 1, 1, 1);
+		knot_packet_free(&qr);
+		return 1;
+	}
 
-		// Stop
-		if (kill(pid, SIGHUP) < 0) {
+	if (r->key) {
+		remote_query_sign(buf, &buflen, qr->max_size, r->key);
+	}
+	
+	/* Send query. */
+	int s = socket_create(r->family, SOCK_STREAM);
+	int conn_state = socket_connect(s, r->address, r->port);
+	if (conn_state != KNOT_EOK || tcp_send(s, buf, buflen) <= 0) {
+		log_server_error("Couldn't connect to remote host "
+		                 " %s@%d.\n", r->address, r->port);
+		rc = 1;
+	}
+	
+	/* Wait for reply. */
+	if (rc == 0) {
+		int ret = cmd_remote_reply(s);
+		if (ret != KNOT_EOK) {
+			log_server_warning("Remote command reply: %s\n",
+			                   knot_strerror(ret));
 			rc = 1;
-		} else {
-			log_server_info("Server reload queued - OK.\n");
 		}
 	}
-	if (strcmp(action, "refresh") == 0) {
-
-		// Check PID
-		valid_cmd = 1;
-		if (pid <= 0 || !pid_running(pid)) {
-			log_server_warning("Server PID not found, "
-			                   "probably not running.\n");
+	
+	/* Cleanup. */
+	knot_rrset_deep_free(&rr, 1, 1, 1);
+	
+	/* Close connection. */
+	socket_close(s);
+	knot_packet_free(&qr);
+	return rc;
+}
 
-			return 1;
-		}
+static knot_lookup_table_t tsig_algn_tbl[] = {
+	{ KNOT_TSIG_ALG_NULL,       "gss-tsig" },
+	{ KNOT_TSIG_ALG_HMAC_MD5,    "hmac-md5" },
+	{ KNOT_TSIG_ALG_HMAC_SHA1,   "hmac-sha1" },
+	{ KNOT_TSIG_ALG_HMAC_SHA224, "hmac-sha224" },
+	{ KNOT_TSIG_ALG_HMAC_SHA256, "hmac-sha256" },
+	{ KNOT_TSIG_ALG_HMAC_SHA384, "hmac-sha384" },
+	{ KNOT_TSIG_ALG_HMAC_SHA512, "hmac-sha512" },
+	{ KNOT_TSIG_ALG_NULL, NULL }
+};
 
-		// Stop
-		if (kill(pid, SIGUSR2) < 0) {
-			rc = 1;
-		} else {
-			log_server_info("Zones refresh queued - OK.\n");
-		}
+static int tsig_parse_str(knot_key_t *key, const char *str)
+{
+	char *h = strdup(str);
+	if (!h) {
+		return KNOT_ENOMEM;
 	}
-	if (strcmp(action, "running") == 0) {
-
-		// Check PID
-		valid_cmd = 1;
-		if (pid <= 0) {
-			log_server_info("Server PID not found, "
-			                "probably not running.\n");
-			rc = 1;
+	
+	char *k = NULL, *s = NULL;
+	if ((k = (char*)strchr(h, ':'))) { /* Second part - NAME|SECRET */
+		*k++ = '\0';               /* String separator */
+		s = (char*)strchr(k, ':'); /* Thirt part - |SECRET */
+	}
+	
+	/* Determine algorithm. */
+	key->algorithm = KNOT_TSIG_ALG_HMAC_MD5;
+	if (s) {
+		*s++ = '\0';               /* Last part separator */
+		knot_lookup_table_t *alg = NULL;
+		alg = knot_lookup_by_name(tsig_algn_tbl, h);
+		if (alg) {
+			key->algorithm = alg->id;
 		} else {
-			if (!pid_running(pid)) {
-				log_server_info("Server PID not found, "
-				                "probably not running.\n");
-				log_server_warning("PID file is stale.\n");
-			} else {
-				log_server_info("Server running as PID %ld.\n",
-				                (long)pid);
-			}
-			rc = 0;
+			free(h);
+			return KNOT_EINVAL;
 		}
+	} else {
+		s = k; /* Ignore first part, push down. */
+		k = h;
 	}
-	if (strcmp(action, "checkconf") == 0) {
-		log_server_info("OK, configuration is valid.\n");
-		rc = 0;
-		valid_cmd = 1;
+	
+	/* Parse key name. */
+	key->name = remote_dname_fqdn(k);
+	key->secret = strdup(s);
+	free(h);
+	
+	/* Check name and secret. */
+	if (!key->name || !key->secret) {
+		return KNOT_EINVAL;
 	}
-	if (strcmp(action, "compile") == 0 || strcmp(action, "checkzone") == 0){
-		
-		// Print job count
-		if (jobs > 1 && argc == 0) {
-			log_server_warning("Will attempt to compile %d zones "
-			                   "in parallel, this increases memory "
-			                   "consumption for large zones.\n",
-			                   jobs);
-		}
-
-		// Zone checking
-		int is_checkzone = (strcmp(action, "checkzone") == 0);
-
-		// Check zone
-		valid_cmd = 1;
-		
-		// Lock configuration
-		rcu_read_lock();
-
-		// Generate databases for all zones
-		node *n = 0;
-		int running = 0;
-		knotc_zctask_t *tasks = zctask_create(jobs);
-		WALK_LIST(n, conf()->zones) {
+	
+	return KNOT_EOK;
+}
 
-			// Fetch zone
-			conf_zone_t *zone = (conf_zone_t*)n;
-			
-			// Specific zone requested
-			int zone_match = 0;
-			for (unsigned i = 0; i < argc; ++i) {
-				size_t len = strlen(zone->name);
-				if (len > 1) {
-					len -= 1;
-				} // All (except root) without final dot
-				if (strncmp(zone->name, argv[i], len) == 0) {
-					zone_match = 1;
-					break;
-				}
-			}
-			if (!zone_match && argc > 0) {
-				continue;
-			}
+static int tsig_parse_line(knot_key_t *k, char *l)
+{
+	const char *n, *a, *s;
+	n = a = s = NULL;
+	int fw = 1; /* 0 = reading word, 1 = between words */
+	while (*l != '\0') {
+		if (isspace(*l) || *l == '"') {
+			*l = '\0';
+			fw = 1; /* End word. */
+		} else if (fw) {
+			if      (!n) { n = l; }
+			else if (!a) { a = l; }
+			else         { s = l; }
+			fw = 0; /* Start word. */
+		}
+		l++;
+	}
 
-			// Check source files and mtime
-			int zone_status = check_zone(zone->db, zone->file);
-			if (zone_status == KNOT_EOK && !is_checkzone) {
-				log_zone_info("Zone '%s' is up-to-date.\n",
-					      zone->name);
-				
-				if (has_flag(flags, F_FORCE)) {
-					log_zone_info("Forcing zone "
-						      "recompilation.\n");
-				} else {
-					continue;
-				}
-			}
-			
-			// Check for not existing source
-			if (zone_status == KNOT_ENOENT) {
-				continue;
-			}
-			
-			
-			/* Evaluate space for new task. */
-			if (running == jobs) {
-				rc |= zctask_wait(tasks, jobs, is_checkzone);
-				--running;
-			}
+	/* No name parsed - assume wrong format. */
+	if (!n) {
+		return KNOT_EMALF;
+	}
+	
+	/* Assume hmac-md5 if no algo specified. */
+	if (!s) {
+		s = a;
+		a = "hmac-md5";
+	}
+	
+	/* Set algorithm. */
+	knot_lookup_table_t *alg = knot_lookup_by_name(tsig_algn_tbl, a);
+	if (alg) {
+		k->algorithm = alg->id;
+	} else {
+		return KNOT_EMALF;
+	}
+	
+	/* Set name. */
+	k->name = remote_dname_fqdn(n);
+	k->secret = strdup(s);
+	
+	/* Check name and secret. */
+	if (!k->name || !k->secret) {
+		return KNOT_EINVAL;
+	}
 
-			int ac = 0;
-			const char *args[7] = { NULL };
-			args[ac++] = ZONEPARSER_EXEC;
-			if (zone->enable_checks) {
-				args[ac++] = "-s";
-			}
-			if (has_flag(flags, F_VERBOSE)) {
-				args[ac++] = "-v";
-			}
-			
-			if (!is_checkzone) {
-				args[ac++] = "-o";
-				args[ac++] = zone->db;
-			}
-			args[ac++] = zone->name;
-			args[ac++] = zone->file;
+	return KNOT_EOK;
+}
 
-			// Execute command
-			if (has_flag(flags, F_VERBOSE) && !is_checkzone) {
-				log_zone_info("Compiling '%s' as '%s'...\n",
-				              zone->name, zone->db);
+static int tsig_parse_file(knot_key_t *k, const char *f)
+{
+	FILE* fp = fopen(f, "r");
+	if (!fp) {
+		log_server_error("Couldn't open key-file '%s'.\n", f);
+		return KNOT_EINVAL;
+	}
+	
+	int c = 0;
+	int ret = KNOT_EOK;
+	char *line = malloc(64);
+	size_t llen = 0;
+	size_t lres = 0;
+	if (line) {
+		lres = 64;
+	}
+	
+	while ((c = fgetc(fp)) != EOF) {
+		if (mreserve(&line, sizeof(char), llen + 1, 512, &lres) != 0) {
+			ret = KNOT_ENOMEM;
+			break;
+		}
+		if (c == '\n') {
+			if (k->name) {
+				log_server_error("Only 1 key definition "
+				                 "allowed in '%s'.\n",
+				                 f);
+				ret = KNOT_EMALF;
+				break;
 			}
-			fflush(stdout);
-			fflush(stderr);
-			pid_t zcpid = start_cmd(args, ac, F_UNPRIVILEGED);
-			zctask_add(tasks, jobs, zcpid, zone);
-			++running;
+			line[llen++] = '\0';
+			ret = tsig_parse_line(k, line);
+			llen = 0;
+		} else {
+			line[llen++] = (char)c;
 		}
 		
-		/* Wait for all running tasks. */
-		while (running > 0) {
-			rc |= zctask_wait(tasks, jobs, is_checkzone);
-			--running;
-		}
-		free(tasks);
-
-		// Unlock configuration
-		rcu_read_unlock();
-	}
-	if (!valid_cmd) {
-		log_server_error("Invalid command: '%s'\n", action);
-		return 1;
 	}
+	
+	free(line);
+	fclose(fp);
+	return ret;
+}
 
-	// Log
-	if (has_flag(flags, F_VERBOSE)) {
-		log_server_info("'%s' finished (return code %d)\n", action, rc);
-	}
-	return rc;
+static void tsig_key_cleanup(knot_key_t *k)
+{
+	knot_dname_free(&k->name);
+	free(k->secret);
 }
 
 int main(int argc, char **argv)
 {
-	// Parse command line arguments
+	/* Parse command line arguments */
 	int c = 0, li = 0;
 	unsigned jobs = 1;
 	unsigned flags = F_NULL;
-	const char* config_fn = 0;
+	char *config_fn = NULL;
+	
+	/* Remote server descriptor. */
+	int ret = KNOT_EOK;
+	const char *r_addr = "127.0.0.1";
+	int r_port = REMOTE_DPORT;
+	knot_key_t r_key;
+	memset(&r_key, 0, sizeof(knot_key_t));
+	
+	/* Initialize. */
+	log_init();
 	
 	/* Long options. */
 	struct option opts[] = {
-		{"wait",        no_argument,       0, 'w'},
-		{"force",       no_argument,       0, 'f'},
-		{"config",      required_argument, 0, 'c'},
-		{"verbose",     no_argument,       0, 'v'},
-		{"interactive", no_argument,       0, 'i'},
-		{"auto",        no_argument,       0, 'a'},
-		{"jobs",        required_argument, 0, 'j'},
-		{"version",     no_argument,       0, 'V'},
-		{"help",        no_argument,       0, 'h'},
+		{"wait", no_argument, 0, 'w'},
+		{"force", no_argument, 0, 'f'},
+		{"config", required_argument, 0, 'c'},
+		{"verbose", no_argument, 0, 'v'},
+		{"interactive", no_argument, 0, 'i'},
+		{"jobs", required_argument, 0, 'j'},
+		{"version", no_argument, 0, 'V'},
+		{"help", no_argument, 0, 'h'},
+		{"server", required_argument, 0, 's' },
+		{"port", required_argument, 0, 's' },
+		{"y", required_argument, 0, 'y' },
+		{"k", required_argument, 0, 'k' },
 		{0, 0, 0, 0}
 	};
-	
-	while ((c = getopt_long(argc, argv, "wfc:viaj:Vh", opts, &li)) != -1) {
+
+	while ((c = getopt_long(argc, argv, "s:p:y:k:wfc:vij:Vh", opts, &li)) != -1) {
 		switch (c) {
-		case 'w': flags |= F_WAIT; break;
-		case 'f': flags |= F_FORCE; break;
-		case 'v': flags |= F_VERBOSE; break;
-		case 'i': flags |= F_INTERACTIVE; break;
-		case 'a': flags |= F_AUTO; break;
+		case 's':
+			r_addr = optarg;
+			break;
+		case 'p':
+			r_port = atoi(optarg);
+			break;
+		case 'y':
+			ret = tsig_parse_str(&r_key, optarg);
+			if (ret != KNOT_EOK) {
+				log_server_error("Couldn't parse TSIG key '%s' "
+				                 "\n", optarg);
+				tsig_key_cleanup(&r_key);
+				log_close();
+				return 1;
+			}
+			break;
+		case 'k':
+			ret = tsig_parse_file(&r_key, optarg);
+			if (ret != KNOT_EOK) {
+				log_server_error("Couldn't parse TSIG key file "
+				                 "'%s'\n", optarg);
+				tsig_key_cleanup(&r_key);
+				log_close();
+				return 1;
+			}
+			break;
+		case 'w':
+			flags |= F_WAIT;
+			break;
+		case 'f':
+			flags |= F_FORCE;
+			break;
+		case 'v':
+			flags |= F_VERBOSE;
+			break;
+		case 'i':
+			flags |= F_INTERACTIVE;
+			break;
 		case 'c':
-			config_fn = optarg;
+			config_fn = strdup(optarg);
 			break;
 		case 'j':
 			jobs = atoi(optarg);
+
 			if (jobs < 1) {
-				fprintf(stderr, "Invalid parameter '%s' to "
-				        "'-j', expects number <1..n>\n",
-				        optarg);
+				log_server_error("Invalid parameter '%s' to '-j'"
+				                 ", expects number <1..n>\n",
+				                 optarg);
 				help(argc, argv);
+				log_close();
 				return 1;
 			}
+
 			break;
 		case 'V':
 			printf("%s, version %s\n", "Knot DNS", PACKAGE_VERSION);
+			log_close();
 			return 0;
 		case 'h':
 		case '?':
 		default:
 			help(argc, argv);
+			log_close();
 			return 1;
 		}
 	}
 
-	// Check if there's at least one remaining non-option
+	/* Check if there's at least one remaining non-option. */
 	if (argc - optind < 1) {
 		help(argc, argv);
+		tsig_key_cleanup(&r_key);
+		log_close();
+		return 1;
+	}
+	
+	/* Find requested command. */
+	knot_cmd_t *cmd = knot_cmd_tbl;
+	while (cmd->name) {
+		if (strcmp(cmd->name, argv[optind]) == 0) {
+			break;
+		}
+		++cmd;
+	}
+	
+	/* Command not found. */
+	if (!cmd->name) {
+		log_server_error("Invalid command: '%s'\n", argv[optind]);
+		tsig_key_cleanup(&r_key);
+		log_close();
 		return 1;
 	}
 
-	// Initialize log
-	log_init();
+	/* Open config, allow if not exists. */
+	if (cmd->need_conf) {
+		if (!config_fn) {
+			config_fn = conf_find_default();
+		}
+		if (conf_open(config_fn) != KNOT_EOK) {
+			flags |= F_NOCONF;
+		}
+		free(config_fn);
+		config_fn = NULL;
+	}
+	
+	/* Discard remote interface. */
+	conf_iface_t *ctl_if = conf()->ctl.iface;
+	conf_free_iface(ctl_if);
+	
+	/* Update remote interface. */
+	ctl_if = malloc(sizeof(conf_iface_t));
+	if (ctl_if) {
+		memset(ctl_if, 0, sizeof(conf_iface_t));
+		ctl_if->address = strdup(r_addr);
+		ctl_if->port = r_port;
+		ctl_if->family = AF_INET;
+		if (strchr(r_addr, ':')) { /* Dumb way to check for v6 addr. */
+			ctl_if->family = AF_INET6;
+		}
+		if (r_key.name) {
+			ctl_if->key = malloc(sizeof(knot_key_t));
+			if (ctl_if->key) {
+				memcpy(ctl_if->key, &r_key, sizeof(knot_key_t));
+			}
+		}
+	}
+	conf()->ctl.iface = ctl_if;
 
-	// Find implicit configuration file
-	char *default_fn = 0;
-	if (!config_fn) {
-		default_fn = conf_find_default();
-		config_fn = default_fn;
+	/* Verbose mode. */
+	if (has_flag(flags, F_VERBOSE)) {
+		log_levels_add(LOGT_STDOUT, LOG_ANY,
+		               LOG_MASK(LOG_INFO) | LOG_MASK(LOG_DEBUG));
 	}
 
-	// Open configuration
-	int conf_ret = conf_open(config_fn);
-	if (conf_ret != KNOT_EOK) {
-		if (conf_ret == KNOT_ENOENT) {
-			log_server_error("Couldn't open configuration file "
-			                 "'%s'.\n", config_fn);
+	/* Execute command. */
+	int rc = cmd->cb(argc - optind - 1, argv + optind + 1, flags, jobs);
+
+	/* Finish */
+	tsig_key_cleanup(&r_key); /* Not cleaned by config deinit. */
+	log_close();
+	return rc;
+}
+
+static int cmd_start(int argc, char *argv[], unsigned flags, int jobs)
+{
+	/* Check config. */
+	if (has_flag(flags, F_NOCONF)) {
+		log_server_error("Couldn't parse config file, refusing to "
+		                 "continue.\n");
+		return 1;
+	}
+	
+	/* Fetch PID. */
+	char *pidfile = pid_filename();
+	pid_t pid = pid_read(pidfile);
+	log_server_info("Starting server...\n");
+	
+	/* Prevent concurrent daemon launch. */
+	int rc = 0;
+	struct stat st;
+	int is_pidf = 0;
+	
+	/* Check PID. */
+	if (pid > 0 && pid_running(pid)) {
+		log_server_error("Server PID found, already running.\n");
+		is_pidf = 1;
+	} else if (stat(pidfile, &st) == 0) {
+		log_server_warning("PID file '%s' exists, another process "
+		                   "is starting or PID file is stale.\n",
+		                   pidfile);
+		is_pidf = 1;
+	}
+	if (is_pidf) {
+		if (!has_flag(flags, F_FORCE)) {
+			free(pidfile);
+			return 1;
 		} else {
-			log_server_error("Failed to load configuration '%s'.\n",
-			                 config_fn);
+			log_server_info("Forcing server start.\n");
+			pid_remove(pidfile);
+			pid = -1;
+		}
+	} else {
+		/* Create empty PID file. */
+		FILE *f = fopen(pidfile, "w");
+		if (f == NULL) {
+			log_server_warning("PID file '%s' is not writeable.\n",
+			                   pidfile);
+			free(pidfile);
+			return 1;
 		}
-		free(default_fn);
+		fclose(f);
+	}
+	
+	/* Recompile zones if needed. */
+	cmd_compile(argc, argv, flags, jobs);
+
+	/* Prepare command */
+	const char *cfg = conf()->filename;
+	size_t args_c = 6;
+	const char *args[] = {
+		PROJECT_EXEC,
+		has_flag(flags, F_INTERACTIVE) ? "" : "-d",
+		cfg ? "-c" : "",
+		cfg ? cfg : "",
+		has_flag(flags, F_VERBOSE) ? "-v" : "",
+		argc > 0 ? argv[0] : ""
+	};
+	
+	/* Execute command */
+	if (has_flag(flags, F_INTERACTIVE)) {
+		log_server_info("Running in interactive mode.\n");
+		fflush(stderr);
+		fflush(stdout);
+	}
+	if ((rc = cmd_exec(args, args_c)) < 0) {
+		pid_remove(pidfile);
+		rc = 1;
+	}
+	fflush(stderr);
+	fflush(stdout);
+
+	/* Wait for finish */
+	if (has_flag(flags, F_WAIT) && !has_flag(flags, F_INTERACTIVE)) {
+		if (has_flag(flags, F_VERBOSE)) {
+			log_server_info("Waiting for server to load.\n");
+		}
+
+		/* Periodically read pidfile and wait for valid result. */
+		pid = 0;
+		while (pid == 0 || !pid_running(pid)) {
+			pid = pid_read(pidfile);
+			struct timeval tv;
+			tv.tv_sec = 0;
+			tv.tv_usec = 500 * 1000;
+			select(0, 0, 0, 0, &tv);
+		}
+	}
+	
+	free(pidfile);
+	return rc;
+}
+
+static int cmd_stop(int argc, char *argv[], unsigned flags, int jobs)
+{
+	/* Check config. */
+	if (has_flag(flags, F_NOCONF)) {
+		log_server_error("Couldn't parse config file, refusing to "
+		                 "continue.\n");
 		return 1;
 	}
+	
+	/* Fetch PID. */
+	char *pidfile = pid_filename();
+	pid_t pid = pid_read(pidfile);
+	int rc = 0;
+	struct stat st;
+	
+	/* Check for non-existent PID file. */
+	int has_pidf = (stat(pidfile, &st) == 0);
+	if(has_pidf && pid <= 0) {
+		log_server_warning("Empty PID file '%s' exists, daemon process "
+		                   "is starting or PID file is stale.\n",
+		                   pidfile);
+		free(pidfile);
+		return 1;
+	} else if (pid <= 0 || !pid_running(pid)) {
+		log_server_warning("Server PID not found, "
+		                   "probably not running.\n");
+		if (!has_flag(flags, F_FORCE)) {
+			free(pidfile);
+			return 1;
+		} else {
+			log_server_info("Forcing server stop.\n");
+		}
+	}
 
-	// Free default config filename if exists
-	free(default_fn);
+	/* Stop */
+	log_server_info("Stopping server...\n");
+	if (kill(pid, SIGTERM) < 0) {
+		pid_remove(pidfile);
+		rc = 1;
+	}
+	
 
-	// Verbose mode
-	if (has_flag(flags, F_VERBOSE)) {
-		log_levels_add(LOGT_STDOUT, LOG_ANY,
-		               LOG_MASK(LOG_INFO)|LOG_MASK(LOG_DEBUG));
+	/* Wait for finish */
+	if (rc == 0 && has_flag(flags, F_WAIT)) {
+		log_server_info("Waiting for server to finish.\n");
+		while (pid_running(pid)) {
+			struct timeval tv;
+			tv.tv_sec = 0;
+			tv.tv_usec = 500 * 1000;
+			select(0, 0, 0, 0, &tv);
+			pid = pid_read(pidfile); /* Update */
+		}
 	}
 	
-	// Fetch PID
-	char* pidfile = pid_filename();
-	if (!pidfile) {
-		log_server_error("No configuration found, "
-		                 "please specify with '-c' parameter.\n");
-		log_close();
+	return rc;
+}
+
+static int cmd_restart(int argc, char *argv[], unsigned flags, int jobs)
+{
+	/* Check config. */
+	if (has_flag(flags, F_NOCONF)) {
+		log_server_error("Couldn't parse config file, refusing to "
+		                 "continue.\n");
 		return 1;
 	}
+	
+	int rc = 0;
+	rc |= cmd_stop(argc, argv, flags | F_WAIT, jobs);
+	rc |= cmd_start(argc, argv, flags, jobs);
+	return rc;
+}
 
-	pid_t pid = pid_read(pidfile);
+static int cmd_reload(int argc, char *argv[], unsigned flags, int jobs)
+{
+	return cmd_remote("reload", KNOT_RRTYPE_TXT, 0, NULL);
+}
 
-	// Actions
-	const char* action = argv[optind];
+static int cmd_refresh(int argc, char *argv[], unsigned flags, int jobs)
+{
+	return cmd_remote("refresh", KNOT_RRTYPE_CNAME, argc, argv);
+}
 
-	// Execute action
-	int rc = execute(action, argv + optind + 1, argc - optind - 1,
-	                 pid, flags, jobs, pidfile);
+static int cmd_flush(int argc, char *argv[], unsigned flags, int jobs)
+{
+	return cmd_remote("flush", KNOT_RRTYPE_CNAME, argc, argv);
+}
 
-	// Finish
-	free(pidfile);
-	log_close();
+static int cmd_status(int argc, char *argv[], unsigned flags, int jobs)
+{
+	return cmd_remote("status", KNOT_RRTYPE_TXT, 0, NULL);
+}
+
+static int cmd_checkconf(int argc, char *argv[], unsigned flags, int jobs)
+{
+	/* Check config. */
+	if (has_flag(flags, F_NOCONF)) {
+		log_server_error("Couldn't parse config file, refusing to "
+		                 "continue.\n");
+		return 1;
+	} else {
+		log_server_info("OK, configuration is valid.\n");
+	}
+	
+	return 0;
+}
+
+static int cmd_checkzone(int argc, char *argv[], unsigned flags, int jobs)
+{
+	return cmd_compile(argc, argv, flags | F_DRYRUN, jobs);
+}
+
+static int cmd_compile(int argc, char *argv[], unsigned flags, int jobs)
+{
+	/* Print job count */
+	if (jobs > 1 && argc == 0) {
+		log_server_warning("Will attempt to compile %d zones "
+		                   "in parallel, this increases memory "
+		                   "consumption for large zones.\n", jobs);
+	}
+
+	/* Zone checking */
+	int rc = 0;
+	node *n = 0;
+	int running = 0;
+	int is_checkzone = has_flag(flags, F_DRYRUN);
+	knotc_zctask_t *tasks = zctask_create(jobs);
+	
+	/* Generate databases for all zones */
+	WALK_LIST(n, conf()->zones) {
+		/* Fetch zone */
+		conf_zone_t *zone = (conf_zone_t *) n;
+		int zone_match = 0;
+		for (unsigned i = 0; i < argc; ++i) {
+			size_t len = strlen(zone->name);
+			
+			/* All (except root) without final dot */
+			if (len > 1) {
+				len -= 1;
+			}
+			if (strncmp(zone->name, argv[i], len) == 0) {
+				zone_match = 1;
+				break;
+			}
+		}
+
+		if (!zone_match && argc > 0) {
+			continue;
+		}
+
+		/* Check source files and mtime */
+		int zone_status = check_zone(zone->db, zone->file);
+		if (zone_status == KNOT_EOK && !is_checkzone) {
+			log_zone_info("Zone '%s' is up-to-date.\n", zone->name);
+			if (has_flag(flags, F_FORCE)) {
+				log_zone_info("Forcing zone "
+				              "recompilation.\n");
+			} else {
+				continue;
+			}
+		}
+
+		/* Check for not existing source */
+		if (zone_status == KNOT_ENOENT) {
+			continue;
+		}
+
+		/* Evaluate space for new task. */
+		if (running == jobs) {
+			rc |= zctask_wait(tasks, jobs, is_checkzone);
+			--running;
+		}
+
+		/* Build executable command. */
+		int ac = 0;
+		const char *args[7] = { NULL };
+		args[ac++] = ZONEPARSER_EXEC;
+		if (zone->enable_checks) {
+			args[ac++] = "-s";
+		}
+		if (has_flag(flags, F_VERBOSE)) {
+			args[ac++] = "-v";
+		}
+		if (!is_checkzone) {
+			args[ac++] = "-o";
+			args[ac++] = zone->db;
+		}
+		args[ac++] = zone->name;
+		args[ac++] = zone->file;
+
+		/* Execute command */
+		if (has_flag(flags, F_VERBOSE) && !is_checkzone) {
+			log_zone_info("Compiling '%s' as '%s'...\n",
+			              zone->name, zone->db);
+		}
+		fflush(stdout);
+		fflush(stderr);
+		pid_t zcpid = pid_start(args, ac,
+		                        has_flag(flags, F_UNPRIVILEGED));
+		zctask_add(tasks, jobs, zcpid, zone);
+		++running;
+	}
+
+	/* Wait for all running tasks. */
+	while (running > 0) {
+		rc |= zctask_wait(tasks, jobs, is_checkzone);
+		--running;
+	}
+
+	free(tasks);
 	return rc;
 }
diff --git a/src/knot/ctl/process.c b/src/knot/ctl/process.c
index 5eb5c2d..94306c2 100644
--- a/src/knot/ctl/process.c
+++ b/src/knot/ctl/process.c
@@ -24,6 +24,7 @@
 #include <grp.h>
 #include <unistd.h>
 #include <assert.h>
+#include <sys/wait.h>
 
 #include "knot/common.h"
 #include "knot/ctl/process.h"
@@ -169,3 +170,63 @@ void proc_update_privileges(int uid, int gid)
 	}
 	free(lfile);
 }
+
+pid_t pid_wait(pid_t proc, int *rc)
+{
+	/* Wait for finish. */
+	sigset_t newset;
+	sigfillset(&newset);
+	sigprocmask(SIG_BLOCK, &newset, 0);
+	proc = waitpid(proc, rc, 0);
+	sigprocmask(SIG_UNBLOCK, &newset, 0);
+	return proc;
+}
+
+
+pid_t pid_start(const char *argv[], int argc, int drop_privs)
+{
+	pid_t chproc = fork();
+	if (chproc == 0) {
+	
+		/* Alter privileges. */
+		if (drop_privs) {
+			proc_update_privileges(conf()->uid, conf()->gid);
+		}
+
+		/* Duplicate, it doesn't run from stack address anyway. */
+		char **args = malloc((argc + 1) * sizeof(char*));
+		memset(args, 0, (argc + 1) * sizeof(char*));
+		int ci = 0;
+		for (int i = 0; i < argc; ++i) {
+			if (strlen(argv[i]) > 0) {
+				args[ci++] = strdup(argv[i]);
+			}
+		}
+		args[ci] = 0;
+
+		/* Execute command. */
+		fflush(stdout);
+		fflush(stderr);
+		execvp(args[0], args);
+
+		/* Execute failed. */
+		log_server_error("Failed to run executable '%s'\n", args[0]);
+		for (int i = 0; i < argc; ++i) {
+			free(args[i]);
+		}
+		free(args);
+
+		exit(1);
+		return -1;
+	}
+	
+	return chproc;
+}
+
+int cmd_exec(const char *argv[], int argc)
+{
+	int ret = 0;
+	pid_t proc = pid_start(argv, argc, 0);
+	pid_wait(proc, &ret);
+	return ret;
+}
diff --git a/src/knot/ctl/process.h b/src/knot/ctl/process.h
index b993f72..b80b968 100644
--- a/src/knot/ctl/process.h
+++ b/src/knot/ctl/process.h
@@ -92,6 +92,39 @@ int pid_running(pid_t pid);
  */
 void proc_update_privileges(int uid, int gid);
 
+/*!
+ * \brief Wait for process to finish.
+ *
+ * \param proc Process ID.
+ * \param rc Destination for return code.
+ *
+ * \return PID of finished process.
+ */
+pid_t pid_wait(pid_t proc, int *rc);
+
+/*!
+ * \brief Start command with given parameters.
+ *
+ * Set drop_privs = 1 to change privileges according to conf().
+ *
+ * \param argv Parameter list.
+ * \param argc Parameter count.
+ * \param drop_privs Set to 1 to alter privileges.
+ *
+ * \return PID of started process.
+ */
+pid_t pid_start(const char *argv[], int argc, int drop_privs);
+
+/*!
+ * \brief Execute command and wait for finish.
+ *
+ * \param argv Parameter list.
+ * \param argc Parameter count.
+ *
+ * \return Return code.
+ */
+int cmd_exec(const char *argv[], int argc);
+
 #endif // _KNOTD_PROCESS_H_
 
 /*! @} */
diff --git a/src/knot/ctl/remote.c b/src/knot/ctl/remote.c
new file mode 100644
index 0000000..ac1e527
--- /dev/null
+++ b/src/knot/ctl/remote.c
@@ -0,0 +1,704 @@
+/*  Copyright (C) 2011 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "remote.h"
+#include "common/log.h"
+#include "common/fdset.h"
+#include "common/prng.h"
+#include "knot/common.h"
+#include "knot/conf/conf.h"
+#include "knot/server/socket.h"
+#include "knot/server/tcp-handler.h"
+#include "knot/server/zones.h"
+#include "libknot/util/wire.h"
+#include "libknot/packet/query.h"
+#include "libknot/packet/response.h"
+#include "libknot/nameserver/name-server.h"
+#include "libknot/tsig-op.h"
+
+#define KNOT_CTL_REALM "knot."
+#define KNOT_CTL_REALM_EXT ("." KNOT_CTL_REALM)
+#define KNOT_CTL_REALM_LEN 5
+
+/*! \brief Remote command structure. */
+typedef struct remote_cmdargs_t {
+	const knot_rrset_t **arg;
+	unsigned argc;
+	knot_rcode_t rc;
+} remote_cmdargs_t;
+
+/*! \brief Callback prototype for remote commands. */
+typedef int (*remote_cmdf_t)(server_t*, remote_cmdargs_t*);
+
+/*! \brief Callback prototype for per-zone operations. */
+typedef int (remote_zonef_t)(server_t*, knot_zone_t *);
+
+/*! \brief Remote command table item. */
+typedef struct remote_cmd_t {
+	const char *name;
+	remote_cmdf_t f;
+} remote_cmd_t;
+
+/* Forward decls. */
+static int remote_c_reload(server_t *s, remote_cmdargs_t* a);
+static int remote_c_refresh(server_t *s, remote_cmdargs_t* a);
+static int remote_c_status(server_t *s, remote_cmdargs_t* a);
+static int remote_c_flush(server_t *s, remote_cmdargs_t* a);
+
+/*! \brief Table of remote commands. */
+struct remote_cmd_t remote_cmd_tbl[] = {
+	{ "reload",    &remote_c_reload },
+	{ "refresh",   &remote_c_refresh },
+	{ "status",    &remote_c_status },
+	{ "flush",     &remote_c_flush },
+	{ NULL,        NULL }
+};
+
+/* Private APIs. */
+
+/*! \brief Apply callback to all zones specified by RDATA of CNAME RRs. */
+static int remote_rdata_apply(server_t *s, remote_cmdargs_t* a, remote_zonef_t *cb)
+{
+	if (!s || !a || !cb) {
+		return KNOT_EINVAL;
+	}
+	
+	knot_nameserver_t *ns = s->nameserver;
+	knot_zone_t *zone = NULL;
+	int ret = KNOT_EOK;
+	
+	/* Refresh specific zones. */
+	for (unsigned i = 0; i < a->argc; ++i) {
+		rcu_read_lock();
+		
+		/* Process all zones in data section. */
+		const knot_rrset_t *rr = a->arg[i];
+		if (knot_rrset_type(rr) != KNOT_RRTYPE_CNAME) {
+			continue;
+		}
+		
+		const knot_rdata_t *rd = knot_rrset_rdata(rr);
+		while (rd != NULL) {
+			/* Skip empty nodes. */
+			if (knot_rdata_item_count(rd) < 1) {
+				rd = knot_rrset_rdata_next(rr, rd);
+				continue;
+			}
+			/* Refresh zones. */
+			const knot_dname_t *dn = knot_rdata_item(rd, 0)->dname;
+			zone = knot_zonedb_find_zone(ns->zone_db, dn);
+			if (cb(s, zone) != KNOT_EOK) {
+				a->rc = KNOT_RCODE_SERVFAIL;
+			}
+			rd = knot_rrset_rdata_next(rr, rd);
+		}
+		rcu_read_unlock();
+	}
+	
+	return ret;
+}
+
+/*! \brief Zone refresh callback. */
+static int remote_zone_refresh(server_t *s, knot_zone_t *z)
+{
+	if (!s || !z) {
+		return KNOT_EINVAL;
+	}
+	
+	knot_nameserver_t *ns =  s->nameserver;
+	evsched_t *sch = ((server_t *)knot_ns_get_data(ns))->sched;
+	zonedata_t *zd = (zonedata_t *)knot_zone_data(z);
+	if (!sch || !zd) {
+		return KNOT_EINVAL;
+	}
+	
+	/* Expire REFRESH timer. */
+	if (zd->xfr_in.timer) {
+		evsched_cancel(sch, zd->xfr_in.timer);
+		evsched_schedule(sch, zd->xfr_in.timer,
+		                 tls_rand() * 1000);
+	}
+	
+	return KNOT_EOK;
+}
+
+/*! \brief Zone flush callback. */
+static int remote_zone_flush(server_t *s, knot_zone_t *z)
+{
+	if (!s || !z) {
+		return KNOT_EINVAL;
+	}
+	
+	knot_nameserver_t *ns =  s->nameserver;
+	evsched_t *sch = ((server_t *)knot_ns_get_data(ns))->sched;
+	zonedata_t *zd = (zonedata_t *)knot_zone_data(z);
+	if (!sch || !zd) {
+		return KNOT_EINVAL;
+	}
+	
+	/* Expire IXFR sync timer. */
+	if (zd->ixfr_dbsync) {
+		evsched_cancel(sch, zd->ixfr_dbsync);
+		evsched_schedule(sch, zd->ixfr_dbsync,
+		                 tls_rand() * 1000);
+	}
+	
+	return KNOT_EOK;
+}
+
+/*! \brief Helper to build RDATA from RDATA item. */
+knot_rdata_t* remote_build_rdata(knot_rdata_item_t *i)
+{
+	/* Create RDATA. */
+	knot_rdata_t *rd = knot_rdata_new();
+	if (!rd) {
+		return NULL;
+	}
+	
+	/* Set RDATA items. */
+	int ret = knot_rdata_set_items(rd, i, 1);
+	if (ret != KNOT_EOK) {
+		knot_rdata_free(&rd);
+		return NULL;
+	}
+	
+	return rd;
+}
+
+/*!
+ * \brief Remote command 'reload' handler.
+ *
+ * QNAME: reload
+ * DATA: NULL
+ */
+static int remote_c_reload(server_t *s, remote_cmdargs_t* a)
+{
+	return server_reload(s, conf()->filename);
+}
+
+/*!
+ * \brief Remote command 'status' handler.
+ *
+ * QNAME: refresh
+ * DATA: NONE
+ */
+static int remote_c_status(server_t *s, remote_cmdargs_t* a)
+{
+	/*! \todo #2035 Add some TXT RRs with stats. */
+	dbg_server("remote: %s\n", __func__);
+	return KNOT_EOK;
+}
+
+/*!
+ * \brief Remote command 'refresh' handler.
+ *
+ * QNAME: refresh
+ * DATA: NONE for all zones
+ *       CNAME RRs with zones in RDATA
+ */
+static int remote_c_refresh(server_t *s, remote_cmdargs_t* a)
+{
+	/* Refresh all. */
+	dbg_server("remote: %s\n", __func__);
+	if (a->argc == 0) {
+		dbg_server_verb("remote: refreshing all zones\n");
+		return server_refresh(s);
+	}
+	
+	/* Refresh specific zones. */
+	return remote_rdata_apply(s, a, &remote_zone_refresh);
+}
+
+/*!
+ * \brief Remote command 'flush' handler.
+ *
+ * QNAME: flush
+ * DATA: NONE for all zones
+ *       CNAME RRs with zones in RDATA
+ */
+static int remote_c_flush(server_t *s, remote_cmdargs_t* a)
+{
+	/* Flush all. */
+	dbg_server("remote: %s\n", __func__);
+	if (a->argc == 0) {
+		dbg_server_verb("remote: flushing all zones\n");
+		return KNOT_ENOTSUP;
+	}
+	
+	/* Flush specific zones. */
+	return remote_rdata_apply(s, a, &remote_zone_flush);
+}
+
+/* Public APIs. */
+
+int remote_bind(conf_iface_t *desc)
+{
+	if (!desc) {
+		return -1;
+	}
+	
+	/* Create new socket. */
+	int s = socket_create(desc->family, SOCK_STREAM);
+	if (s < 0) {
+		log_server_error("Couldn't create socket for remote "
+				 "control interface - %s",
+				 knot_strerror(s));
+		return KNOT_ERROR;
+	}
+	
+	/* Bind to interface and start listening. */
+	int r = socket_bind(s, desc->family, desc->address, desc->port);
+	if (r == KNOT_EOK) {
+		r = socket_listen(s, TCP_BACKLOG_SIZE);
+	}
+	if (r != KNOT_EOK) {
+		socket_close(s);
+		log_server_error("Could not bind to "
+				 "remote control interface %s port %d.\n",
+				 desc->address, desc->port);
+		return r;
+	}
+	
+	return s;
+}
+
+int remote_unbind(int r)
+{
+	if (r < 0) {
+		return KNOT_EINVAL;
+	}
+	
+	return socket_close(r);
+}
+
+int remote_poll(int r)
+{
+	if (r < 0) {
+		return -1;
+	}
+	
+	/* Wait for events. */
+	fd_set rfds;
+	FD_ZERO(&rfds);
+	FD_SET(r, &rfds);
+	return fdset_pselect(r + 1, &rfds, NULL, NULL, NULL, NULL);
+}
+
+int remote_recv(int r, sockaddr_t *a, uint8_t* buf, size_t *buflen)
+{
+	int c = tcp_accept(r);
+	if (c < 0) {
+		dbg_server("remote: couldn't accept incoming connection\n");
+		return c;
+	}
+
+	/* Receive data. */
+	int n = tcp_recv(c, buf, *buflen, a);
+	*buflen = n;
+	if (n <= 0) {
+		dbg_server("remote: failed to receive data\n");
+		socket_close(c);
+		return KNOT_ECONNREFUSED;
+	}
+	
+	return c;
+}
+
+int remote_parse(knot_packet_t* pkt, const uint8_t* buf, size_t buflen)
+{
+	knot_packet_type_t qtype = KNOT_QUERY_NORMAL;
+	int ret = knot_ns_parse_packet(buf, buflen, pkt, &qtype);
+	if (ret != KNOT_EOK) {
+		dbg_server("remote: failed to parse packet\n");
+		return KNOT_EINVAL;
+	}
+	ret = knot_packet_parse_rest(pkt);
+	if (ret != KNOT_EOK) {
+		dbg_server("remote: failed to parse packet data\n");
+		return KNOT_EINVAL;
+	}
+	
+	return ret;
+}
+
+int remote_answer(server_t *s, knot_packet_t *pkt, uint8_t* rwire, size_t *rlen)
+{
+	if (!s || !pkt || !rwire) {
+		*rlen = 0;
+		return KNOT_EINVAL;
+	}
+	
+	/* Prerequisites:
+	 * QCLASS: CH
+	 * QNAME: <CMD>.KNOT_CTL_REALM.
+	 */
+	const knot_dname_t *qname = knot_packet_qname(pkt);
+	if (knot_packet_qclass(pkt) != KNOT_CLASS_CH) {
+		dbg_server("remote: qclass != CH\n");
+		*rlen = 0;
+		return KNOT_EMALF;
+	}
+	
+	knot_dname_t *realm = knot_dname_new_from_str(KNOT_CTL_REALM,
+	                                              KNOT_CTL_REALM_LEN, NULL);
+	if (!knot_dname_is_subdomain(qname, realm) != 0) {
+		dbg_server("remote: qname != *%s\n", KNOT_CTL_REALM_EXT);
+		knot_dname_free(&realm);
+		*rlen = 0;
+		return KNOT_EMALF;
+	}
+	knot_dname_free(&realm);
+	
+	/* Command:
+	 * QNAME: leftmost label of QNAME
+	 */
+	size_t cmd_len = knot_dname_label_size(qname, 0);
+	char *cmd = strndup((char*)qname->name + 1, cmd_len);
+
+	/* Data:
+	 * NS: TSIG
+	 * AR: data
+	 */
+	int ret = KNOT_EOK;
+	remote_cmd_t *c = remote_cmd_tbl;
+	remote_cmdargs_t args;
+	args.arg = pkt->authority;
+	args.argc = knot_packet_authority_rrset_count(pkt);
+	args.rc = KNOT_RCODE_NOERROR;
+	while(c->name != NULL) {
+		if (strcmp(cmd, c->name) == 0) {
+			ret = c->f(s, &args);
+			break;
+		}
+		++c;
+	}
+	
+	/* Prepare response. */
+	size_t remaining = *rlen;
+	knot_packet_t *resp = knot_packet_new(KNOT_PACKET_PREALLOC_RESPONSE);
+	if (!resp) {
+		free(cmd);
+		return ret;
+	}
+	uint8_t *wire = NULL;
+	size_t len = 0;
+	ret = knot_packet_set_max_size(resp, SOCKET_MTU_SZ);
+	if (ret != KNOT_EOK)  {
+		free(cmd);
+		knot_packet_free(&resp);
+		return ret;
+	}
+	ret = knot_response_init_from_query(resp, pkt, 1);
+	if (ret != KNOT_EOK)  {
+		free(cmd);
+		knot_packet_free(&resp);
+		return ret;
+	}
+	ret = knot_packet_to_wire(resp, &wire, &len);
+	if (ret != KNOT_EOK)  {
+                free(cmd);
+                knot_packet_free(&resp);
+                return ret;
+        }
+	if (len > 0) {
+		memcpy(rwire, wire, len);
+		*rlen = len;
+	}
+	knot_packet_free(&resp);
+	
+	/* Evaluate output. */
+	int rr_count = 0;
+	knot_rrset_t *rr = remote_build_rr("result.", KNOT_RRTYPE_TXT);
+	knot_rdata_t *rd = remote_create_txt(knot_strerror(ret));
+	knot_rrset_add_rdata(rr, rd);
+		
+	remaining -= *rlen;
+	knot_rrset_to_wire(rr, rwire + *rlen, &remaining, &rr_count);
+	knot_wire_set_nscount(rwire, 1);
+	*rlen += remaining;
+	knot_rrset_deep_free(&rr, 1, 1, 1);
+	
+	free(cmd);
+	return ret;
+}
+
+int remote_process(server_t *s, int r, uint8_t* buf, size_t buflen)
+{
+	knot_packet_t *pkt =  knot_packet_new(KNOT_PACKET_PREALLOC_QUERY);
+	if (!pkt) {
+		dbg_server("remote: not enough space to allocate query\n");
+		return KNOT_ENOMEM;
+	}
+	
+	/* Initialize remote party address. */
+	rcu_read_lock();
+	sockaddr_t a;
+	conf_iface_t *ctl_if = conf()->ctl.iface;
+	if (ctl_if) {
+		sockaddr_init(&a, ctl_if->family);
+	}
+	rcu_read_unlock();
+	
+	/* Accept incoming connection and read packet. */
+	size_t wire_len = buflen;
+	int c = remote_recv(r, &a, buf, &wire_len);
+	if (c < 0) {
+		dbg_server("remote: couldn't receive query = %d\n", c);
+		knot_packet_free(&pkt);
+		return c;
+	}
+	
+	/* Parse packet and answer if OK. */
+	int ret = remote_parse(pkt, buf, wire_len);
+	if (ret == KNOT_EOK) {
+		
+		/* Check ACL list. */
+		rcu_read_lock();
+		knot_key_t *k = NULL;
+		acl_key_t *m = NULL;
+		knot_rcode_t ts_rc = 0;
+		uint16_t ts_trc = 0;
+		uint64_t ts_tmsigned = 0;
+		const knot_rrset_t *tsig_rr = knot_packet_tsig(pkt);
+		if (acl_match(conf()->ctl.acl, &a, &m) == ACL_DENY) {
+			knot_packet_free(&pkt);
+			socket_close(c);
+			rcu_read_unlock();
+			return KNOT_EACCES;
+		}
+		if (m && m->val) {
+			k = ((conf_iface_t *)m->val)->key;
+		}
+		rcu_read_unlock();
+		
+		/* Check TSIG. */
+		if (k) {
+			if (!tsig_rr) {
+				knot_packet_free(&pkt);
+				socket_close(c);
+				return KNOT_EACCES;
+			}
+			ret = zones_verify_tsig_query(pkt, k, &ts_rc,
+			                              &ts_trc, &ts_tmsigned);
+			if (ret != KNOT_EOK) {
+				dbg_server("remote: failed to verify TSIG, "
+				           "RC: %u TSIG_RC: %u\n",
+				           ts_rc, ts_trc);
+				knot_packet_free(&pkt);
+				socket_close(c);
+				return KNOT_EACCES;
+			}
+		}
+		
+		/* Answer packet. */
+		wire_len = buflen;
+		remote_answer(s, pkt, buf, &wire_len);
+		if (wire_len > 0) {
+			tcp_send(c, buf, wire_len);
+		}
+	}
+	
+	knot_packet_free(&pkt);
+	socket_close(c);
+	return ret;
+}
+
+knot_packet_t* remote_query(const char *query, const knot_key_t *key)
+{
+	if (!query) {
+		return NULL;
+	}
+	
+	knot_packet_t *qr = knot_packet_new(KNOT_PACKET_PREALLOC_QUERY);
+	if (!qr) {
+		return NULL;
+	}
+	
+	knot_packet_set_max_size(qr, 512);
+	knot_query_init(qr);
+	knot_packet_set_random_id(qr);
+	
+	/* Reserve space for TSIG. */
+	if (key) {
+		knot_packet_set_tsig_size(qr, tsig_wire_maxsize(key));
+	}
+	
+	/* Question section. */
+	knot_question_t q;
+	char *qname = strcdup(query, KNOT_CTL_REALM_EXT);
+	q.qname = knot_dname_new_from_str(qname, strlen(qname), 0);
+	if (!q.qname) {
+		knot_packet_free(&qr);
+		free(qname);
+		return NULL;
+	}
+	q.qtype = KNOT_RRTYPE_ANY;
+	q.qclass = KNOT_CLASS_CH;
+
+	/* Cannot return != KNOT_EOK, but still. */
+	if (knot_query_set_question(qr, &q) != KNOT_EOK) {
+		knot_packet_free(&qr);
+        	free(qname);
+        	return NULL;
+	}
+
+	knot_dname_release(q.qname);
+	free(qname);
+	
+	return qr;
+}
+
+int remote_query_append(knot_packet_t *qry, knot_rrset_t *data)
+{
+	if (!qry || !data) {
+		return KNOT_EINVAL;
+	}
+	
+	uint8_t *sp = qry->wireformat + qry->size;
+	uint8_t *np   = qry->wireformat + qry->max_size;
+	uint8_t *p = sp;
+	const knot_rdata_t *rd = knot_rrset_rdata(data);
+	while (rd != NULL) {
+		int ret = knot_query_rr_to_wire(data, rd, &p, np);
+		if (ret == KNOT_EOK) {
+			qry->header.nscount += 1;
+		}
+		rd = knot_rrset_rdata_next(data, rd);
+	}
+
+	/* Finalize packet size. */
+	qry->size += (p - sp);
+	return KNOT_EOK;
+}
+
+
+int remote_query_sign(uint8_t *wire, size_t *size, size_t maxlen,
+                      const knot_key_t *key)
+{
+	if (!wire || !size || !key) {
+		return KNOT_EINVAL;
+	}
+	
+	size_t dlen = tsig_alg_digest_length(key->algorithm);
+	uint8_t *digest = malloc(dlen);
+	if (!digest) {
+		return KNOT_ENOMEM;
+	}
+	
+	int ret = knot_tsig_sign(wire, size, maxlen, NULL, 0, digest, &dlen,
+	                         key, 0, 0);
+	free(digest);
+	
+	return ret;
+}
+
+knot_rrset_t* remote_build_rr(const char *k, uint16_t t)
+{
+	if (!k) {
+		return NULL;
+	}
+	
+	/* Assert K is FQDN. */
+	knot_dname_t *key = remote_dname_fqdn(k);
+	if (!key) {
+		return NULL;
+	}
+	
+	/* Create RRSet. */
+	knot_rrset_t *rr = knot_rrset_new(key, t, KNOT_CLASS_CH, 0);
+	knot_dname_release(key);
+	return rr;
+}
+
+knot_rdata_t* remote_create_txt(const char *v)
+{
+	if (!v) {
+		return NULL;
+	}
+
+	/* Create raw_data item. */
+	size_t v_len = strlen(v);
+	knot_rdata_item_t i;
+	i.raw_data = malloc(v_len + 3);
+	if (!i.raw_data) {
+		return NULL;
+	}
+	*i.raw_data = v_len + 1;
+	
+	/* Write TXT item. */
+	uint8_t *raw_item = (uint8_t*)(i.raw_data + 1);
+	*(raw_item++) = v_len;
+	memcpy(raw_item, v, v_len);
+	
+	knot_rdata_t *rd = remote_build_rdata(&i);
+	if (!rd) {
+		free(i.raw_data);
+	}
+	
+	return rd;
+}
+
+knot_rdata_t* remote_create_cname(const char *d)
+{
+	if (!d) {
+		return NULL;
+	}
+
+	/* Create dname item. */
+	knot_rdata_item_t i;
+	knot_dname_t *dn = remote_dname_fqdn(d);
+	i.dname = dn;
+	
+	/* Build RDATA. */
+	knot_rdata_t *rd = remote_build_rdata(&i);
+	if (!rd) {
+		knot_dname_release(dn);
+	}
+	
+	return rd;
+}
+
+char* remote_parse_txt(const knot_rdata_t *rd)
+{
+	if (!rd || knot_rdata_count(rd) < 1) {
+		return NULL;
+	}
+	
+	const knot_rdata_item_t *ri = knot_rdata_item(rd, 0);
+	if (!ri) {
+		return NULL;
+	}
+	
+	/* Packet parser should have already checked the packet validity. */
+	uint8_t item_len = ri->raw_data[1] & 0x00ff;
+	return strndup(((const char*)ri->raw_data) + 3, item_len);
+}
+
+knot_dname_t* remote_dname_fqdn(const char *k)
+{
+	/*! \todo #2035 knot_dname_new_from_str() should ensure final '.' */
+	knot_dname_t *key = NULL;
+	size_t key_len = strlen(k);
+	if (k[key_len - 1] != '.') {
+		char *fqdn = strcdup(k, ".");
+		key = knot_dname_new_from_str(fqdn, key_len + 1, NULL);
+		free(fqdn);
+	} else {
+		key = knot_dname_new_from_str(k, key_len, NULL);
+	}
+	return key;
+}
+
diff --git a/src/knot/ctl/remote.h b/src/knot/ctl/remote.h
new file mode 100644
index 0000000..eb3eb81
--- /dev/null
+++ b/src/knot/ctl/remote.h
@@ -0,0 +1,204 @@
+/*  Copyright (C) 2011 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+/*!
+ * \file remote.h
+ *
+ * \author Marek Vavrusa <marek.vavrusa@nic.cz>
+ *
+ * \brief Functions for remote control interface.
+ *
+ * \addtogroup ctl
+ * @{
+ */
+
+#ifndef _KNOTD_REMOTE_H_
+#define _KNOTD_REMOTE_H_
+
+#include <config.h>
+#include "knot/conf/conf.h"
+#include "libknot/packet/packet.h"
+#include "libknot/rrset.h"
+#include "libknot/rdata.h"
+#include "knot/server/server.h"
+
+/*! \brief Default remote control tool port. */
+#define REMOTE_DPORT 5553
+
+/*!
+ * \brief Bind RC interface according to configuration.
+ * \param desc Interface descriptor (address, port).
+ *
+ * \retval socket if passed.
+ * \retval knot_error else.
+ */
+int remote_bind(conf_iface_t *desc);
+
+/*!
+ * \brief Unbind from RC interface and close socket.
+ *
+ * \note Breaks all pending connections.
+ *
+ * \param r RC interface socket
+ *
+ * \retval KNOT_EOK on success.
+ * \retval knot_error else.
+ */
+int remote_unbind(int r);
+
+/*!
+ * \brief Poll new events on RC socket.
+ * \param r RC interface socket.
+ *
+ * \return number of polled events or -1 on error.
+ */
+int remote_poll(int r);
+
+/*!
+ * \brief Start a RC connection with remote.
+ *
+ * \param r RC interface socket.
+ * \param a Destination for remote party address (or NULL if not interested).
+ * \param buf Buffer for RC command.
+ * \param buflen Maximum buffer size.
+ *
+ * \return client TCP socket if success.
+ * \return KNOT_ECONNREFUSED if fails to receive command.
+ */
+int remote_recv(int r, sockaddr_t *a, uint8_t* buf, size_t *buflen);
+
+/*!
+ * \brief Parse a RC command.
+ *
+ * \param pkt Dst structure for parsed command.
+ * \param buf Remote command in wire format.
+ * \param buflen Wire format length.
+ *
+ * \retval KNOT_EOK on success.
+ * \retval knot_error else.
+ */
+int remote_parse(knot_packet_t* pkt, const uint8_t* buf, size_t buflen);
+
+/*!
+ * \brief Execute command and prepare answer for client.
+ *
+ * \param s Server instance.
+ * \param pkt Parsed RC command.
+ * \param rwire Buffer for response.
+ * \param rlen Maximum buffer size for response.
+ *
+ * \retval KNOT_EOK on success.
+ * \retval knot_error else.
+ */
+int remote_answer(server_t *s, knot_packet_t *pkt, uint8_t* rwire, size_t *rlen);
+
+/*!
+ * \brief Accept new client, receive command, process it and send response.
+ *
+ * \note This should be used as a high-level API for workers.
+ *
+ * \param s Server instance.
+ * \param r RC interface socket.
+ * \param buf Buffer for commands/responses.
+ * \param buflen Maximum buffer size.
+ *
+ * \retval KNOT_EOK on success.
+ * \retval knot_error else.
+ */
+int remote_process(server_t *s, int r, uint8_t* buf, size_t buflen);
+
+/* Functions for creating RC packets. */
+
+/*!
+ * \brief Build a RC command packet, TSIG key is optional.
+ *
+ * \note This doesn't sign packet, see remote_query_sign().
+ *
+ * \param query Command name, f.e. 'reload'.
+ * \param key TSIG key for space reservation (or NULL).
+ *
+ * \retval KNOT_EOK on success.
+ * \retval knot_error else.
+ */
+knot_packet_t* remote_query(const char *query, const knot_key_t *key);
+
+/*!
+ * \brief Append extra data to RC command packet.
+ *
+ * \param qry RC packet.
+ * \param data Extra data in form of a RR set.
+ *
+ * \retval KNOT_EOK on success.
+ * \retval knot_error else.
+ */
+int remote_query_append(knot_packet_t *qry, knot_rrset_t *data);
+
+/*!
+ * \brief Sign a RC command packet using TSIG key.
+ *
+ * \param wire RC packet in wire format.
+ * \param size RC packet size.
+ * \param maxlen Maximum buffer size.
+ * \param key TSIG key.
+ *
+ * \retval KNOT_EOK on success.
+ * \retval knot_error else.
+ */
+int remote_query_sign(uint8_t *wire, size_t *size, size_t maxlen,
+                      const knot_key_t *key);
+
+/*! \todo #1291 RR building should be a part of DNS library. */
+
+/*!
+ * \brief Create a RR of a given name and type.
+ *
+ * \param k RR set name.
+ * \param t RR set type.
+ *
+ * \return created RR set or NULL.
+ */
+knot_rrset_t* remote_build_rr(const char *k, uint16_t t);
+
+/*!
+ * \brief Create a TXT rdata.
+ * \param v Text as a string.
+ * \return Created rdata or NULL.
+ */
+knot_rdata_t* remote_create_txt(const char *v);
+
+/*!
+ * \brief Create a CNAME rdata.
+ * \param d Domain name as a string.
+ * \return Created rdata or NULL.
+ */
+knot_rdata_t* remote_create_cname(const char *d);
+
+/*!
+ * \brief Parse TXT rdata to string.
+ * \param rd TXT rdata.
+ * \return Parsed string or NULL.
+ */
+char* remote_parse_txt(const knot_rdata_t *rd);
+
+/*!
+ * \brief Create dname from str and make sure the name is FQDN.
+ * \param k Domain name as string.
+ * \return Created FQDN or NULL.
+ */
+knot_dname_t* remote_dname_fqdn(const char *k);
+
+#endif // _KNOTD_REMOTE_H_
+
+/*! @} */
diff --git a/src/knot/main.c b/src/knot/main.c
index de37de4..b3d8b8d 100644
--- a/src/knot/main.c
+++ b/src/knot/main.c
@@ -30,9 +30,11 @@
 #include "knot/common.h"
 #include "knot/server/server.h"
 #include "knot/ctl/process.h"
+#include "knot/ctl/remote.h"
 #include "knot/conf/conf.h"
 #include "knot/conf/logconf.h"
 #include "knot/server/zones.h"
+#include "knot/server/tcp-handler.h"
 
 /*----------------------------------------------------------------------------*/
 
@@ -300,10 +302,25 @@ int main(int argc, char **argv)
 		sa.sa_flags = 0;
 		pthread_sigmask(SIG_BLOCK, &sa.sa_mask, NULL);
 
+		/* Bind to control interface. */
+		uint8_t buf[65535]; /*! \todo #2035 should be on heap */
+		size_t buflen = sizeof(buf);
+		conf_iface_t *ctl_if = conf()->ctl.iface;
+		int remote = -1;
+		if (ctl_if != NULL) {
+			log_server_info("Binding remote control interface "
+					"to %s port %d.\n",
+					ctl_if->address, ctl_if->port);
+			remote = remote_bind(ctl_if);
+		} else {
+			remote = evqueue()->fds[EVQUEUE_READFD];
+		}
+		
+		
 		/* Run event loop. */
 		for(;;) {
 			pthread_sigmask(SIG_UNBLOCK, &sa.sa_mask, NULL);
-			int ret = evqueue_poll(evqueue(), 0, 0);
+			int ret = remote_poll(remote);
 			pthread_sigmask(SIG_BLOCK, &sa.sa_mask, NULL);
 
 			/* Interrupts. */
@@ -313,25 +330,8 @@ int main(int argc, char **argv)
 				break;
 			}
 			if (sig_req_reload) {
-				log_server_info("Reloading configuration...\n");
 				sig_req_reload = 0;
-				int cf_ret = conf_open(config_fn);
-				switch (cf_ret) {
-				case KNOT_EOK:
-					log_server_info("Configuration "
-							"reloaded.\n");
-					break;
-				case KNOT_ENOENT:
-					log_server_error("Configuration "
-							 "file '%s' "
-							 "not found.\n",
-							 conf()->filename);
-					break;
-				default:
-					log_server_error("Configuration "
-							 "reload failed.\n");
-					break;
-				}
+				server_reload(server, config_fn);
 			}
 			if (sig_req_refresh) {
 				log_server_info("Refreshing slave zones...\n");
@@ -347,17 +347,17 @@ int main(int argc, char **argv)
 
 			/* Events. */
 			if (ret > 0) {
-				event_t ev;
-				if (evqueue_get(evqueue(), &ev) == 0) {
-					dbg_server_verb("Event: "
-					                "received new event.\n");
-					if (ev.cb) {
-						ev.cb(&ev);
-					}
-				}
+				remote_process(server, remote, buf, buflen);
+
 			}
 		}
 		pthread_sigmask(SIG_UNBLOCK, &sa.sa_mask, NULL);
+		
+		/* Close remote control interface */
+		if (remote > -1) {
+			close(remote);
+			remote = -1;
+		}
 
 		if ((server_wait(server)) != KNOT_EOK) {
 			log_server_error("An error occured while "
diff --git a/src/knot/server/journal.c b/src/knot/server/journal.c
index ac393cf..1623bf5 100644
--- a/src/knot/server/journal.c
+++ b/src/knot/server/journal.c
@@ -715,16 +715,21 @@ int journal_read(journal_t *journal, uint64_t id, journal_cmp_t cf, char *dst)
 		return KNOT_ENOENT;
 	}
 
+	return journal_read_node(journal, n, dst);
+}
+
+int journal_read_node(journal_t *journal, journal_node_t *n, char *dst)
+{
+	dbg_journal("journal: reading node with id=%llu, data=<%u, %u>, flags=0x%hx\n",
+	            n->id, n->pos, n->pos + n->len, n->flags);
+
 	/* Check valid flag. */
 	if (!(n->flags & JOURNAL_VALID)) {
 		dbg_journal("journal: node with id=%llu is invalid "
 		            "(flags=0x%hx)\n", (unsigned long long)n->id, n->flags);
 		return KNOT_EINVAL;
 	}
-
-	dbg_journal("journal: reading node with id=%llu, data=<%u, %u>, flags=0x%hx\n",
-	            (unsigned long long)id, n->pos, n->pos + n->len, n->flags);
-
+	
 	/* Seek journal node. */
 	int seek_ret = lseek(journal->fd, n->pos, SEEK_SET);
 
@@ -732,7 +737,7 @@ int journal_read(journal_t *journal, uint64_t id, journal_cmp_t cf, char *dst)
 	if (seek_ret < 0 || !sfread(dst, n->len, journal->fd)) {
 		return KNOT_ERROR;
 	}
-
+	
 	return KNOT_EOK;
 }
 
diff --git a/src/knot/server/journal.h b/src/knot/server/journal.h
index f6716ae..9462809 100644
--- a/src/knot/server/journal.h
+++ b/src/knot/server/journal.h
@@ -129,7 +129,7 @@ typedef int (*journal_apply_t)(journal_t *j, journal_node_t *n);
 #define JOURNAL_NCOUNT 1024 /*!< Default node count. */
 /* HEADER = magic, crc, max_entries, qhead, qtail */
 #define JOURNAL_HSIZE (MAGIC_LENGTH + sizeof(crc_t) + sizeof(uint16_t) * 3) 
-#define JOURNAL_MAGIC {'k', 'n', 'o', 't', '1', '0', '4'}
+#define JOURNAL_MAGIC {'k', 'n', 'o', 't', '1', '0', '5'}
 
 /*!
  * \brief Create new journal.
@@ -186,6 +186,21 @@ int journal_fetch(journal_t *journal, uint64_t id,
 int journal_read(journal_t *journal, uint64_t id, journal_cmp_t cf, char *dst);
 
 /*!
+ * \brief Read journal entry data.
+ *
+ * \param journal Associated journal.
+ * \param n Entry.
+ * \param dst Pointer to destination memory.
+ *
+ * \retval KNOT_EOK if successful.
+ * \retval KNOT_ENOENT if the entry cannot be found.
+ * \retval KNOT_EINVAL if the entry is invalid.
+ * \retval KNOT_ERROR on I/O error.
+ */
+int journal_read_node(journal_t *journal, journal_node_t *n, char *dst);
+
+
+/*!
  * \brief Write journal entry data.
  *
  * \param journal Associated journal.
diff --git a/src/knot/server/notify.c b/src/knot/server/notify.c
index 381b1b2..3eb99a0 100644
--- a/src/knot/server/notify.c
+++ b/src/knot/server/notify.c
@@ -123,7 +123,7 @@ int notify_create_response(knot_packet_t *request, uint8_t *buffer,
 	/* Set maximum packet size. */
 	int rc = knot_packet_set_max_size(response, *size);
 	if (rc == KNOT_EOK) {
-		rc = knot_response_init_from_query(response, request);
+		rc = knot_response_init_from_query(response, request, 1);
 	}
 	
 	/* Aggregated result check. */
diff --git a/src/knot/server/server.c b/src/knot/server/server.c
index 5a792c7..e42460f 100644
--- a/src/knot/server/server.c
+++ b/src/knot/server/server.c
@@ -635,7 +635,8 @@ int server_refresh(server_t *server)
 		if (zd->xfr_in.timer) {
 			evsched_cancel(sch, zd->xfr_in.timer);
 			evsched_schedule(sch, zd->xfr_in.timer,
-			                 tls_rand() * 1000);
+			                 tls_rand() * 500 + i*200);
+			/* Cumulative delay. */
 		}
 	}
 	
@@ -645,6 +646,35 @@ int server_refresh(server_t *server)
 	return KNOT_EOK;
 }
 
+int server_reload(server_t *server, const char *cf)
+{
+	if (!server || !cf) {
+		return KNOT_EINVAL;
+	}
+	
+	log_server_info("Reloading configuration...\n");
+	int cf_ret = conf_open(cf);
+	switch (cf_ret) {
+	case KNOT_EOK:
+		log_server_info("Configuration "
+				"reloaded.\n");
+		break;
+	case KNOT_ENOENT:
+		log_server_error("Configuration "
+				 "file '%s' "
+				 "not found.\n",
+				 conf()->filename);
+		break;
+	default:
+		log_server_error("Configuration "
+				 "reload failed.\n");
+		break;
+	}
+	
+	/*! \todo Close and bind to new remote control. */
+	return cf_ret;
+}
+
 void server_stop(server_t *server)
 {
 	dbg_server("server: stopping server\n");
diff --git a/src/knot/server/server.h b/src/knot/server/server.h
index a28be63..fa7597f 100644
--- a/src/knot/server/server.h
+++ b/src/knot/server/server.h
@@ -189,6 +189,15 @@ int server_wait(server_t *server);
 int server_refresh(server_t *server);
 
 /*!
+ * \brief Reload server configuration.
+ *
+ * \param server Server instance.
+ * \param cf Config file path.
+ * \return 
+ */
+int server_reload(server_t *server, const char *cf);
+
+/*!
  * \brief Requests server to stop.
  *
  * \param server Server structure to be used for operation.
diff --git a/src/knot/server/socket.c b/src/knot/server/socket.c
index 5f4f936..6a32d4d 100644
--- a/src/knot/server/socket.c
+++ b/src/knot/server/socket.c
@@ -55,6 +55,7 @@ int socket_connect(int fd, const char *addr, unsigned short port)
 	/* Resolve address. */
 	int ret = KNOT_EOK;
 	struct addrinfo hints, *res;
+	memset(&hints, 0, sizeof(struct addrinfo));
 	hints.ai_family = AF_UNSPEC;
 	hints.ai_socktype = SOCK_STREAM;
 	if ((ret = getaddrinfo(addr, NULL, &hints, &res)) != 0) {
@@ -202,4 +203,3 @@ int socket_close(int socket)
 
 	return KNOT_EOK;
 }
-
diff --git a/src/knot/server/socket.h b/src/knot/server/socket.h
index 1266c53..8bbd6cc 100644
--- a/src/knot/server/socket.h
+++ b/src/knot/server/socket.h
@@ -114,7 +114,6 @@ int socket_listen(int fd, int backlog_size);
  */
 int socket_close(int fd);
 
-
 #endif // _KNOTD_SOCKET_H_
 
 /*! @} */
diff --git a/src/knot/server/tcp-handler.c b/src/knot/server/tcp-handler.c
index 11628bc..06f42c2 100644
--- a/src/knot/server/tcp-handler.c
+++ b/src/knot/server/tcp-handler.c
@@ -170,9 +170,11 @@ static int tcp_handle(tcp_worker_t *w, int fd, uint8_t *qbuf, size_t qbuf_maxlen
 			char r_addr[SOCKADDR_STRLEN];
 			sockaddr_tostr(&addr, r_addr, sizeof(r_addr));
 			int r_port = sockaddr_portnum(&addr);
+			rcu_read_lock();
 			log_server_warning("Couldn't receive query from '%s@%d'"
 			                  " within the time limit of %ds.\n",
-			                   r_addr, r_port, TCP_ACTIVITY_WD);
+			                   r_addr, r_port, conf()->max_conn_idle);
+			rcu_read_unlock();
 		}
 		return KNOT_ECONNREFUSED;
 	}
@@ -250,10 +252,12 @@ static int tcp_handle(tcp_worker_t *w, int fd, uint8_t *qbuf, size_t qbuf_maxlen
 		return xfr_answer(ns, &xfr);
 		
 	case KNOT_QUERY_UPDATE:
-		knot_ns_error_response_from_query(ns, packet,
-		                                  KNOT_RCODE_NOTIMPL,
-		                                  qbuf, &resp_len);
-		res = KNOT_EOK;
+//		knot_ns_error_response_from_query(ns, packet,
+//		                                  KNOT_RCODE_NOTIMPL,
+//		                                  qbuf, &resp_len);
+		res = zones_process_update(ns, packet, &addr, qbuf, &resp_len,
+		                           fd, NS_TRANSPORT_TCP);
+//		res = KNOT_EOK;
 		break;
 		
 	case KNOT_QUERY_NOTIFY:
@@ -294,7 +298,7 @@ static int tcp_handle(tcp_worker_t *w, int fd, uint8_t *qbuf, size_t qbuf_maxlen
 	return res;
 }
 
-static int tcp_accept(int fd)
+int tcp_accept(int fd)
 {
 	/* Accept incoming connection. */
 	int incoming = accept(fd, 0, 0);
@@ -322,7 +326,9 @@ static int tcp_accept(int fd)
 		/* Set recv() timeout. */
 #ifdef SO_RCVTIMEO
 		struct timeval tv;
-		tv.tv_sec = TCP_ACTIVITY_WD;
+		rcu_read_lock();
+		tv.tv_sec = conf()->max_conn_idle;
+		rcu_read_unlock();
 		tv.tv_usec = 0;
 		if (setsockopt(incoming, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)) < 0) {
 			log_server_warning("Couldn't set up TCP connection "
@@ -554,6 +560,12 @@ int tcp_loop_worker(dthread_t *thread)
 		if (nfds < 0) {
 			continue;
 		}
+		
+		/* Establish timeouts. */
+		rcu_read_lock();
+		int max_idle = conf()->max_conn_idle;
+		int max_hs = conf()->max_conn_hs;
+		rcu_read_unlock();
 
 		/* Process incoming events. */
 		dbg_net_verb("tcp: worker %p registered %d events\n",
@@ -574,19 +586,19 @@ int tcp_loop_worker(dthread_t *thread)
 				             w, client);
 				fdset_add(w->fdset, client, OS_EV_READ);
 				fdset_set_watchdog(w->fdset, client,
-				                   TCP_HANDSHAKE_WD);
+				                   max_hs);
 				dbg_net("tcp: watchdog for fd=%d set to %ds\n",
-				        client, TCP_HANDSHAKE_WD);
+				        client, max_hs);
 			} else {
 				/* Handle other events. */
 				int ret = tcp_handle(w, it.fd, qbuf,
 				                     TCP_BUFFER_SIZE);
 				if (ret == KNOT_EOK) {
 					fdset_set_watchdog(w->fdset, it.fd,
-					                   TCP_ACTIVITY_WD);
+					                   max_idle);
 					dbg_net("tcp: watchdog for fd=%d "
 					        "set to %ds\n",
-					        it.fd, TCP_ACTIVITY_WD);
+					        it.fd, max_idle);
 				}
 				/*! \todo Refactor to allow erase on iterator.*/
 				if (ret == KNOT_ECONNREFUSED) {
diff --git a/src/knot/server/tcp-handler.h b/src/knot/server/tcp-handler.h
index 17a7293..6c38e0a 100644
--- a/src/knot/server/tcp-handler.h
+++ b/src/knot/server/tcp-handler.h
@@ -38,11 +38,18 @@
 #include "knot/server/dthreads.h"
 
 /* Constants */
-#define TCP_HANDSHAKE_WD 10 /* [secs] for connection to make a request.*/
-#define TCP_ACTIVITY_WD  60 /* [secs] of allowed inactivity between requests */
 #define TCP_SWEEP_INTERVAL 2 /* [secs] granularity of connection sweeping */
 
 /*!
+ * \brief Accept a TCP connection.
+ * \param fd Associated socket.
+ *
+ * \retval Created connection fd if success.
+ * \retval <0 on error.
+ */
+int tcp_accept(int fd);
+
+/*!
  * \brief Send TCP message.
  *
  * \param fd Associated socket.
diff --git a/src/knot/server/udp-handler.c b/src/knot/server/udp-handler.c
index d0a21bb..e34c710 100644
--- a/src/knot/server/udp-handler.c
+++ b/src/knot/server/udp-handler.c
@@ -162,11 +162,12 @@ int udp_handle(int fd, uint8_t *qbuf, size_t qbuflen, size_t *resp_len,
 		break;
 		
 	case KNOT_QUERY_UPDATE:
-		dbg_net("udp: UPDATE query on fd=%d not implemented\n", fd);
-		knot_ns_error_response_from_query(ns, packet,
-		                                  KNOT_RCODE_NOTIMPL, qbuf,
-		                                  resp_len);
-		res = KNOT_EOK;
+//		dbg_net("udp: UPDATE query on fd=%d not implemented\n", fd);
+//		knot_ns_error_response_from_query(ns, packet,
+//		                                  KNOT_RCODE_NOTIMPL, qbuf,
+//		                                  resp_len);
+		res = zones_process_update(ns, packet, addr, qbuf, resp_len,
+		                           fd, NS_TRANSPORT_UDP);
 		break;
 		
 	/* Unhandled opcodes. */
diff --git a/src/knot/server/xfr-handler.c b/src/knot/server/xfr-handler.c
index 5e8c31a..6a9a249 100644
--- a/src/knot/server/xfr-handler.c
+++ b/src/knot/server/xfr-handler.c
@@ -34,13 +34,13 @@
 #include "knot/server/udp-handler.h"
 #include "knot/server/tcp-handler.h"
 #include "libknot/updates/xfr-in.h"
+#include "libknot/util/wire.h"
 #include "knot/server/zones.h"
 #include "libknot/tsig-op.h"
 #include "common/evsched.h"
 #include "common/prng.h"
 
 /* Constants */
-#define XFR_QUERY_WD 10 /*!< SOA/NOTIFY query timeout [s]. */
 #define XFR_SWEEP_INTERVAL 2 /*! [seconds] between sweeps. */
 #define XFR_BUFFER_SIZE 65535 /*! Do not change this - maximum value for UDP packet length. */
 #define XFR_MSG_DLTTR 9 /*! Index of letter differentiating IXFR/AXFR in log msg. */
@@ -251,13 +251,19 @@ static int xfr_process_udp_resp(xfrworker_t *w, int fd, knot_ns_xfr_t *data)
 	rcu_read_unlock();
 	
 	/* Receive msg. */
-	ssize_t n = recvfrom(data->session, data->wire, data->wire_size,
-	                     0, data->addr.ptr, &data->addr.len);
+	ssize_t n = -1;
 	size_t resp_len = data->wire_size;
+	if (data->flags & XFR_FLAG_TCP) {
+		n = tcp_recv(data->session, data->wire, resp_len, &data->addr);
+	} else {
+		n = recvfrom(data->session, data->wire, resp_len,
+		             0, data->addr.ptr, &data->addr.len);
+	}
+	
 	if (n <= 0) {
 		return ret;
 	}
-	
+
 	// parse packet
 	knot_packet_t *re = knot_packet_new(KNOT_PACKET_PREALLOC_RESPONSE);
 	if (re == NULL) {
@@ -270,12 +276,18 @@ static int xfr_process_udp_resp(xfrworker_t *w, int fd, knot_ns_xfr_t *data)
 		knot_packet_free(&re);
 		return KNOT_EOK; /* Ignore */
 	}
-	
+
 	/* Ignore other packets. */
-	if (rt != KNOT_RESPONSE_NORMAL && rt != KNOT_RESPONSE_NOTIFY) {
+	switch(rt) {
+	case KNOT_RESPONSE_NORMAL:
+	case KNOT_RESPONSE_NOTIFY:
+	case KNOT_RESPONSE_UPDATE:
+		break;
+	default:
 		knot_packet_free(&re);
 		return KNOT_EOK; /* Ignore */
 	}
+
 	ret = knot_packet_parse_rest(re);
 	if (ret != KNOT_EOK) {
 		knot_packet_free(&re);
@@ -302,6 +314,7 @@ static int xfr_process_udp_resp(xfrworker_t *w, int fd, knot_ns_xfr_t *data)
 	}
 	
 	// process response
+	size_t qlen = n;
 	switch(rt) {
 	case KNOT_RESPONSE_NORMAL:
 		ret = zones_process_response(w->ns, &data->addr, re,
@@ -311,10 +324,17 @@ static int xfr_process_udp_resp(xfrworker_t *w, int fd, knot_ns_xfr_t *data)
 		ret = notify_process_response(w->ns, re, &data->addr,
 		                              data->wire, &resp_len);
 		break;
+	case KNOT_RESPONSE_UPDATE:
+		ret = zones_process_update_response(data, data->wire, &qlen);
+		if (ret == KNOT_EOK) {
+			log_server_info("%s Forwarded response.\n",
+			                data->msgpref);
+		}
+		break;
 	default:
 		break;
 	}
-
+	
 	knot_packet_free(&re);
 	
 	/* Check up-to-date zone. */
@@ -349,6 +369,7 @@ static void xfr_sweep(fdset_t *set, int fd, void *data)
 	switch(t->type) {
 	case XFR_TYPE_SOA:
 	case XFR_TYPE_NOTIFY:
+	case XFR_TYPE_FORWARD:
 		xfr_udp_timeout(t);
 		break;
 	default:
@@ -420,10 +441,10 @@ static int xfr_xfrin_finalize(xfrworker_t *w, knot_ns_xfr_t *data)
 {
 
 	int ret = KNOT_EOK;
-	int apply_ret = KNOT_EOK;
+//	int apply_ret = KNOT_EOK;
 	int switch_ret = KNOT_EOK;
 	knot_changesets_t *chs = NULL;
-	journal_t *transaction = NULL;
+//	journal_t *transaction = NULL;
 	
 	switch(data->type) {
 	case XFR_TYPE_AIN:
@@ -450,82 +471,11 @@ static int xfr_xfrin_finalize(xfrworker_t *w, knot_ns_xfr_t *data)
 		break;
 	case XFR_TYPE_IIN:
 		chs = (knot_changesets_t *)data->data;
-
-		/* Serialize and store changesets. */
-		dbg_xfr("xfr: IXFR/IN serializing and saving changesets\n");
-		transaction = zones_store_changesets_begin(data);
-		if (transaction != NULL) {
-			ret = zones_store_changesets(data);
-		} else {
-			ret = KNOT_ERROR;
-		}
-		if (ret != KNOT_EOK) {
-			log_zone_error("%s Failed to serialize and store "
-			               "changesets - %s\n", data->msgpref,
-			               knot_strerror(ret));
-			/* Free changesets, but not the data. */
-			knot_free_changesets(&chs);
-			data->data = NULL;
-			break;
-		}
-
-		/* Now, try to apply the changesets to the zone. */
-		apply_ret = xfrin_apply_changesets(data->zone, chs,
-		                                       &data->new_contents);
-
-		if (apply_ret != KNOT_EOK) {
-			zones_store_changesets_rollback(transaction);
-			log_zone_error("%s Failed to apply changesets - %s\n",
-			               data->msgpref,
-			               knot_strerror(apply_ret));
-
-			/* Free changesets, but not the data. */
-			knot_free_changesets(&chs);
-			data->data = NULL;
-			ret = KNOT_ERROR;
-			break;
-		}
-		
-		/* Commit transaction. */
-		ret = zones_store_changesets_commit(transaction);
-		if (ret != KNOT_EOK) {
-			log_zone_error("%s Failed to commit stored changesets "
-			               "- %s\n",
-			               data->msgpref,
-			               knot_strerror(apply_ret));
-			knot_free_changesets(&chs);
-			data->data = NULL;
-			break;
-		}
-
-		/* Switch zone contents. */
-		switch_ret = xfrin_switch_zone(data->zone, data->new_contents,
-		                               data->type);
-
-		if (switch_ret != KNOT_EOK) {
-			log_zone_error("%s Failed to replace "
-				       "current zone - %s\n",
-				       data->msgpref,
-				       knot_strerror(switch_ret));
-			// Cleanup old and new contents
-			xfrin_rollback_update(data->zone->contents,
-			                      &data->new_contents,
-			                      &chs->changes);
-
-			/* Free changesets, but not the data. */
-			knot_free_changesets(&chs);
-			data->data = NULL;
-			ret = KNOT_ERROR;
-			break;
-		}
-
-		xfrin_cleanup_successful_update(&chs->changes);
-
-		/* Free changesets, but not the data. */
-		knot_free_changesets(&chs);
+		ret = zones_store_and_apply_chgsets(chs, data->zone,
+		                                    &data->new_contents,
+		                                    data->msgpref, 
+		                                    XFR_TYPE_IIN);
 		data->data = NULL;
-		assert(ret == KNOT_EOK);
-		log_zone_info("%s Finished.\n", data->msgpref);
 		break;
 	default:
 		ret = KNOT_EINVAL;
@@ -687,8 +637,13 @@ int xfr_process_event(xfrworker_t *w, int fd, knot_ns_xfr_t *data, uint8_t *buf,
 	data->wire_size = buflen;
 
 	/* Handle SOA/NOTIFY responses. */
-	if (data->type == XFR_TYPE_NOTIFY || data->type == XFR_TYPE_SOA) {
+	switch(data->type) {
+	case XFR_TYPE_NOTIFY:
+	case XFR_TYPE_SOA:
+	case XFR_TYPE_FORWARD:
 		return xfr_process_udp_resp(w, fd, data);
+	default:
+		break;
 	}
 
 	/* Read DNS/TCP packet. */
@@ -890,9 +845,15 @@ static int xfr_client_start(xfrworker_t *w, knot_ns_xfr_t *data)
 				                   data->msgpref);
 			} else {
 				ret = connect(fd, data->addr.ptr, data->addr.len);
+				if (ret < 0) {
+					dbg_xfr("%s: couldn't connect to "
+					        "remote host\n", data->msgpref);
+				}
 			}
 		} else {
 			ret = -1;
+			dbg_xfr("%s: couldn't create socket err=%d\n",
+			        data->msgpref, errno);
 		}
 		
 		if (ret < 0) {
@@ -1085,31 +1046,17 @@ static int xfr_update_msgpref(knot_ns_xfr_t *req, const char *keytag)
 	if (req == NULL) {
 		return KNOT_EINVAL;
 	}
-
+	
 	rcu_read_lock();
-	char r_addr[SOCKADDR_STRLEN];
 	char *r_key = NULL;
-	int r_port = sockaddr_portnum(&req->addr);
-	sockaddr_tostr(&req->addr, r_addr, sizeof(r_addr));
-	char *tag = NULL;
 	if (keytag) {
-		tag = strdup(keytag);
+		r_key = xfr_remote_str(&req->addr, keytag);
 	} else if (req->tsig_key) {
-		tag = knot_dname_to_str(req->tsig_key->name);
-	}
-	if (tag) {
-		/* Allocate: " key '$key' " (7 extra bytes + \0)  */
-		size_t dnlen = strlen(tag);
-		r_key = malloc(dnlen + 7 + 1);
-		if (r_key) {
-			char *kp = r_key;
-			memcpy(kp, " key '", 6); kp += 6;
-			/* Trim trailing '.' */
-			memcpy(kp, tag, dnlen); kp += dnlen - 1;
-			memcpy(kp, "'", 2); /* 1 + '\0' */
-		}
+		char *tag = knot_dname_to_str(req->tsig_key->name);
+		r_key = xfr_remote_str(&req->addr, tag);
 		free(tag);
-		tag = NULL;
+	} else {
+		r_key = xfr_remote_str(&req->addr, NULL);
 	}
 
 	/* Prepare log message. */
@@ -1127,40 +1074,33 @@ static int xfr_update_msgpref(knot_ns_xfr_t *req, const char *keytag)
 	const char *pformat = NULL;
 	switch (req->type) {
 	case XFR_TYPE_AIN:
-		pformat = "Incoming AXFR transfer of '%s' with '%s@%d'%s:";
+		pformat = "Incoming AXFR transfer of '%s' with %s:";
 		break;
 	case XFR_TYPE_IIN:
-		pformat = "Incoming IXFR transfer of '%s' with '%s@%d'%s:";
+		pformat = "Incoming IXFR transfer of '%s' with %s:";
 		break;
 	case XFR_TYPE_AOUT:
-		pformat = "Outgoing AXFR transfer of '%s' to '%s@%d'%s:";
+		pformat = "Outgoing AXFR transfer of '%s' to %s:";
 		break;
 	case XFR_TYPE_IOUT:
-		pformat = "Outgoing IXFR transfer of '%s' to '%s@%d'%s:";
+		pformat = "Outgoing IXFR transfer of '%s' to %s:";
 		break;
 	case XFR_TYPE_NOTIFY:
-		pformat = "NOTIFY query of '%s' to '%s@%d'%s:";
+		pformat = "NOTIFY query of '%s' to %s:";
 		break;
 	case XFR_TYPE_SOA:
-		pformat = "SOA query of '%s' to '%s@%d'%s:";
+		pformat = "SOA query of '%s' to %s:";
+		break;
+	case XFR_TYPE_FORWARD:
+		pformat = "UPDATE forwarded query of '%s' to %s:";
 		break;
 	default:
-		pformat = "";
+		pformat = "UNKNOWN query '%s' from %s:";
 		break;
 	}
 
-	int len = 512;
-	char *msg = malloc(len + 1);
+	char *msg = sprintf_alloc(pformat, zname, r_key ? r_key : "'unknown'");
 	if (msg) {
-		memset(msg, 0, len + 1);
-		len = snprintf(msg, len + 1, pformat, zname, r_addr, r_port,
-		               r_key ? r_key : ""); 
-		/* Shorten as some implementations (<C99) don't allow
-		 * printing to NULL to estimate size. */
-		if (len > 0) {
-			msg = realloc(msg, len + 1);
-		}
-		
 		req->msgpref = msg;
 	}
 	
@@ -1441,7 +1381,6 @@ int xfr_answer(knot_nameserver_t *ns, knot_ns_xfr_t *xfr)
 	}
 	
 	/* Finally, answer AXFR/IXFR. */
-	int io_error = 0;
 	if (!xfr_failed) {
 		switch(xfr->type) {
 		case XFR_TYPE_AOUT:
@@ -1457,14 +1396,15 @@ int xfr_answer(knot_nameserver_t *ns, knot_ns_xfr_t *xfr)
 		
 		xfr_failed = (ret != KNOT_EOK);
 		errstr = knot_strerror(ret);
-		io_error = (ret == KNOT_ECONN);
+	} else {
+		knot_ns_error_response_from_query(ns, xfr->query,  xfr->rcode,
+		                                  xfr->wire, &xfr->wire_size);
+		/*! \todo Sign with TSIG for some errors. */
+		ret = xfr->send(xfr->session, &xfr->addr, xfr->wire, xfr->wire_size);
 	}
 	
 	/* Check results. */
 	if (xfr_failed) {
-		if (!io_error) {
-			knot_ns_xfr_send_error(ns, xfr, xfr->rcode);
-		}
 		log_server_notice("%s %s\n", xfr->msgpref, errstr);
 	} else {
 		log_server_info("%s Finished.\n", xfr->msgpref);
@@ -1532,9 +1472,9 @@ static int xfr_process_request(xfrworker_t *w, uint8_t *buf, size_t buflen)
 		/* Report. */
 		if (ret != KNOT_EOK && ret != KNOT_EACCES) {
 			if (zd != NULL && !knot_zone_contents(xfr.zone)) {
-				/* Reschedule request (120 - 240s random delay). */
-				int tmr_s = AXFR_BOOTSTRAP_RETRY * 2; /* Malus x2 */
-				tmr_s += (int)((120.0 * 1000) * tls_rand());
+				/* Reschedule request delay. */
+				int tmr_s = AXFR_BOOTSTRAP_RETRY;
+				tmr_s += (int)((tmr_s) * tls_rand());
 				event_t *ev = zd->xfr_in.timer;
 				if (ev) {
 					evsched_cancel(ev->parent, ev);
@@ -1553,6 +1493,7 @@ static int xfr_process_request(xfrworker_t *w, uint8_t *buf, size_t buflen)
 		break;
 	case XFR_TYPE_SOA:
 	case XFR_TYPE_NOTIFY:
+	case XFR_TYPE_FORWARD:
 		/* Register task. */
 		task = xfr_register_task(w, &xfr);
 		if (!task) {
@@ -1560,8 +1501,17 @@ static int xfr_process_request(xfrworker_t *w, uint8_t *buf, size_t buflen)
 			ret = KNOT_ENOMEM;
 		} else {
 			/* Add timeout. */
-			fdset_set_watchdog(w->fdset, task->session, XFR_QUERY_WD);
-			log_server_info("%s Query issued.\n", xfr.msgpref);
+			rcu_read_lock();
+			fdset_set_watchdog(w->fdset, task->session,
+			                   conf()->max_conn_reply);
+			rcu_read_unlock();
+			if (xfr.type == XFR_TYPE_FORWARD) {
+				log_server_info("%s Forwarded query.\n",
+				                xfr.msgpref);
+			} else {
+				log_server_info("%s Query issued.\n",
+				                xfr.msgpref);
+			}
 			ret = KNOT_EOK;
 		}
 		break;
@@ -1715,3 +1665,27 @@ int xfr_prepare_tsig(knot_ns_xfr_t *xfr, knot_key_t *key)
 	
 	return ret;
 }
+
+char *xfr_remote_str(const sockaddr_t *addr, const char *key)
+{
+	if (!addr) {
+		return NULL;
+	}
+	
+	/* Prepare address strings. */
+	char r_addr[SOCKADDR_STRLEN];
+	int r_port = sockaddr_portnum(addr);
+	sockaddr_tostr(addr, r_addr, sizeof(r_addr));
+	
+	/* Prepare key strings. */
+	char *tag = "";
+	char *q = "'";
+	if (key) {
+		tag = " key "; /* Prefix */
+	} else {
+		key = tag; /* Both empty. */
+		q = tag;
+	}
+	
+	return sprintf_alloc("'%s@%d'%s%s%s%s", r_addr, r_port, tag, q, key, q);
+}
diff --git a/src/knot/server/xfr-handler.h b/src/knot/server/xfr-handler.h
index 581f47f..9f52752 100644
--- a/src/knot/server/xfr-handler.h
+++ b/src/knot/server/xfr-handler.h
@@ -181,6 +181,16 @@ int xfr_worker(dthread_t *thread);
  */
 int xfr_prepare_tsig(knot_ns_xfr_t *xfr, knot_key_t *key);
 
+/*!
+ * \brief Return formatted string of the remote as 'ip@port key $key'.
+ *
+ * \param addr Remote address.
+ * \param keytag Used TSIG key name (or NULL).
+ *
+ * \return formatted string or NULL.
+ */
+char *xfr_remote_str(const sockaddr_t *addr, const char *keytag);
+
 #endif // _KNOTD_XFRHANDLER_H_
 
 /*! @} */
diff --git a/src/knot/server/zones.c b/src/knot/server/zones.c
index 930f611..935f3a4 100644
--- a/src/knot/server/zones.c
+++ b/src/knot/server/zones.c
@@ -38,6 +38,7 @@
 #include "libknot/tsig-op.h"
 #include "libknot/packet/response.h"
 #include "libknot/zone/zone-diff.h"
+#include "libknot/updates/ddns.h"
 
 static const size_t XFRIN_CHANGESET_BINARY_SIZE = 100;
 static const size_t XFRIN_CHANGESET_BINARY_STEP = 100;
@@ -59,6 +60,11 @@ static int zones_send_cb(int fd, sockaddr_t *addr, uint8_t *msg, size_t msglen)
 	return tcp_send(fd, msg, msglen);
 }
 
+static int zones_send_udp(int fd, sockaddr_t *addr, uint8_t *msg, size_t msglen)
+{
+	return sendto(fd, msg, msglen, 0, addr->ptr, addr->len);
+}
+
 /*----------------------------------------------------------------------------*/
 
 /*! \brief Zone data destructor function. */
@@ -90,7 +96,7 @@ static int zonedata_destroy(knot_zone_t *zone)
 		evsched_event_free(sch, zd->xfr_in.expire);
 		zd->xfr_in.expire = 0;
 	}
-
+	
 	/* Remove list of pending NOTIFYs. */
 	pthread_mutex_lock(&zd->lock);
 	notify_ev_t *ev = 0, *evn = 0;
@@ -115,6 +121,7 @@ static int zonedata_destroy(knot_zone_t *zone)
 	acl_delete(&zd->xfr_out);
 	acl_delete(&zd->notify_in);
 	acl_delete(&zd->notify_out);
+	acl_delete(&zd->update_in);
 
 	/* Close IXFR db. */
 	journal_release(zd->ixfr_db);
@@ -150,9 +157,10 @@ static int zonedata_init(conf_zone_t *cfg, knot_zone_t *zone)
 	pthread_mutex_init(&zd->lock, 0);
 
 	/* Initialize ACLs. */
-	zd->xfr_out = 0;
-	zd->notify_in = 0;
-	zd->notify_out = 0;
+	zd->xfr_out = NULL;
+	zd->notify_in = NULL;
+	zd->notify_out = NULL;
+	zd->update_in = NULL;
 
 	/* Initialize XFR-IN. */
 	sockaddr_init(&zd->xfr_in.master, -1);
@@ -1049,6 +1057,8 @@ static inline uint64_t ixfrdb_key_make(uint32_t from, uint32_t to)
 
 int zones_changesets_from_binary(knot_changesets_t *chgsets)
 {
+	/*! \todo #1291 Why doesn't this just increment stream ptr? */
+	
 	assert(chgsets != NULL);
 	assert(chgsets->allocated >= chgsets->count);
 	/*
@@ -1059,11 +1069,16 @@ int zones_changesets_from_binary(knot_changesets_t *chgsets)
 	int ret = 0;
 
 	for (int i = 0; i < chgsets->count; ++i) {
-
-		/* Read initial changeset RRSet - SOA. */
+		
+		/* Read changeset flags. */
 		knot_changeset_t* chs = chgsets->sets + i;
 		size_t remaining = chs->size;
-		ret = knot_zload_rrset_deserialize(&rrset, chs->data, &remaining);
+		memcpy(&chs->flags, chs->data, sizeof(uint32_t));
+		remaining -= sizeof(uint32_t);
+		
+		/* Read initial changeset RRSet - SOA. */
+		uint8_t *stream = chs->data + (chs->size - remaining);
+		ret = knot_zload_rrset_deserialize(&rrset, stream, &remaining);
 		if (ret != KNOT_EOK) {
 			dbg_xfr("xfr: SOA: failed to deserialize data "
 			        "from changeset, %s\n", knot_strerror(ret));
@@ -1088,7 +1103,7 @@ int zones_changesets_from_binary(knot_changesets_t *chgsets)
 
 			/* Parse next RRSet. */
 			rrset = 0;
-			uint8_t *stream = chs->data + (chs->size - remaining);
+			stream = chs->data + (chs->size - remaining);
 			ret = knot_zload_rrset_deserialize(&rrset, stream, &remaining);
 			if (ret != KNOT_EOK) {
 				dbg_xfr("xfr: failed to deserialize data "
@@ -1213,6 +1228,12 @@ static int zones_load_changesets(const knot_zone_t *zone,
 			journal_release(j);
 			return KNOT_ERROR;
 		}
+		
+		/* Skip wrong changesets. */
+		if (!(n->flags & JOURNAL_VALID) || n->flags & JOURNAL_TRANS) {
+			++n;
+			continue;
+		}
 
 		/* Initialize changeset. */
 		dbg_xfr_detail("xfr: reading entry #%zu id=%llu\n",
@@ -1227,7 +1248,7 @@ static int zones_load_changesets(const knot_zone_t *zone,
 		}
 
 		/* Read journal entry. */
-		ret = journal_read(j, n->id, 0, (char*)chs->data);
+		ret = journal_read_node(j, n, (char*)chs->data);
 		if (ret != KNOT_EOK) {
 			dbg_xfr("xfr: failed to read data from journal\n");
 			free(chs->data);
@@ -1517,11 +1538,13 @@ static int zones_insert_zone(conf_zone_t *z, knot_zone_t **dst,
 		zones_set_acl(&zd->xfr_out, &z->acl.xfr_out);
 		zones_set_acl(&zd->notify_in, &z->acl.notify_in);
 		zones_set_acl(&zd->notify_out, &z->acl.notify_out);
+		zones_set_acl(&zd->update_in, &z->acl.update_in);
 
 		/* Update server pointer. */
 		zd->server = (server_t *)knot_ns_get_data(ns);
 
 		/* Update master server address. */
+		zd->xfr_in.has_master = 0;
 		memset(&zd->xfr_in.tsig_key, 0, sizeof(knot_key_t));
 		sockaddr_init(&zd->xfr_in.master, -1);
 		sockaddr_init(&zd->xfr_in.via, -1);
@@ -1536,6 +1559,7 @@ static int zones_insert_zone(conf_zone_t *z, knot_zone_t **dst,
 				sockaddr_copy(&zd->xfr_in.via,
 				              &cfg_if->via);
 			}
+			zd->xfr_in.has_master = 1;
 
 			if (cfg_if->key) {
 				memcpy(&zd->xfr_in.tsig_key,
@@ -1822,6 +1846,7 @@ dbg_zones_exec(
 			WALK_LIST_FREE(zconf->acl.xfr_out);
 			WALK_LIST_FREE(zconf->acl.notify_in);
 			WALK_LIST_FREE(zconf->acl.notify_out);
+			WALK_LIST_FREE(zconf->acl.update_in);
 			
 			/* Remove from zone db. */
 			knot_zone_t * rm = knot_zonedb_remove_zone(db_old,
@@ -1837,117 +1862,6 @@ dbg_zones_exec(
 
 /*----------------------------------------------------------------------------*/
 
-static int zones_verify_tsig_query(const knot_packet_t *query,
-                                   const knot_rrset_t *tsig_rr,
-                                   const knot_key_t *key,
-                                   knot_rcode_t *rcode, uint16_t *tsig_rcode,
-                                   uint64_t *tsig_prev_time_signed)
-{
-	assert(tsig_rr != NULL);
-	assert(key != NULL);
-	assert(rcode != NULL);
-	assert(tsig_rcode != NULL);
-
-	/*
-	 * 1) Check if we support the requested algorithm.
-	 */
-	tsig_algorithm_t alg = tsig_rdata_alg(tsig_rr);
-	if (tsig_alg_digest_length(alg) == 0) {
-		log_answer_info("Unsupported digest algorithm "
-		                "requested, treating as bad key\n");
-		/*! \todo [TSIG] It is unclear from RFC if I
-		 *               should treat is as a bad key
-		 *               or some other error.
-		 */
-		*rcode = KNOT_RCODE_NOTAUTH;
-		*tsig_rcode = KNOT_TSIG_RCODE_BADKEY;
-		return KNOT_TSIG_EBADKEY;
-	}
-
-	const knot_dname_t *kname = knot_rrset_owner(tsig_rr);
-	assert(kname != NULL);
-
-	/*
-	 * 2) Find the particular key used by the TSIG.
-	 *    Check not only name, but also the algorithm.
-	 */
-	if (key && kname && knot_dname_compare(key->name, kname) == 0
-	    && key->algorithm == alg) {
-		dbg_zones_verb("Found claimed TSIG key for comparison\n");
-	} else {
-		*rcode = KNOT_RCODE_NOTAUTH;
-		*tsig_rcode = KNOT_TSIG_RCODE_BADKEY;
-		return KNOT_TSIG_EBADKEY;
-	}
-
-	/*
-	 * 3) Validate the query with TSIG.
-	 */
-	/* Prepare variables for TSIG */
-	/*! \todo These need to be saved to the response somehow. */
-	//size_t tsig_size = tsig_wire_maxsize(key);
-	size_t digest_max_size = tsig_alg_digest_length(key->algorithm);
-	//size_t digest_size = 0;
-	//uint64_t tsig_prev_time_signed = 0;
-	//uint8_t *digest = (uint8_t *)malloc(digest_max_size);
-	//memset(digest, 0 , digest_max_size);
-
-	/* Copy MAC from query. */
-	dbg_zones_verb("Validating TSIG from query\n");
-
-	//const uint8_t* mac = tsig_rdata_mac(tsig_rr);
-	size_t mac_len = tsig_rdata_mac_length(tsig_rr);
-
-	int ret = KNOT_EOK;
-
-	if (mac_len > digest_max_size) {
-		*rcode = KNOT_RCODE_FORMERR;
-		dbg_zones("MAC length %zu exceeds digest "
-		       "maximum size %zu\n", mac_len, digest_max_size);
-		return KNOT_EMALF;
-	} else {
-		//memcpy(digest, mac, mac_len);
-		//digest_size = mac_len;
-
-		/* Check query TSIG. */
-		ret = knot_tsig_server_check(tsig_rr,
-		                             knot_packet_wireformat(query),
-		                             knot_packet_size(query), key);
-		dbg_zones_verb("knot_tsig_server_check() returned %s\n",
-		               knot_strerror(ret));
-
-		/* Evaluate TSIG check results. */
-		switch(ret) {
-		case KNOT_EOK:
-			*rcode = KNOT_RCODE_NOERROR;
-			break;
-		case KNOT_TSIG_EBADKEY:
-			*tsig_rcode = KNOT_TSIG_RCODE_BADKEY;
-			*rcode = KNOT_RCODE_NOTAUTH;
-			break;
-		case KNOT_TSIG_EBADSIG:
-			*tsig_rcode = KNOT_TSIG_RCODE_BADSIG;
-			*rcode = KNOT_RCODE_NOTAUTH;
-			break;
-		case KNOT_TSIG_EBADTIME:
-			*tsig_rcode = KNOT_TSIG_RCODE_BADTIME;
-			// store the time signed from the query
-			*tsig_prev_time_signed = tsig_rdata_time_signed(tsig_rr);
-			*rcode = KNOT_RCODE_NOTAUTH;
-			break;
-		case KNOT_EMALF:
-			*rcode = KNOT_RCODE_FORMERR;
-			break;
-		default:
-			*rcode = KNOT_RCODE_SERVFAIL;
-		}
-	}
-
-	return ret;
-}
-
-/*----------------------------------------------------------------------------*/
-
 static int zones_check_tsig_query(const knot_zone_t *zone,
                                   knot_packet_t *query,
                                   const sockaddr_t *addr,
@@ -1961,34 +1875,11 @@ static int zones_check_tsig_query(const knot_zone_t *zone,
 	assert(rcode != NULL);
 	assert(tsig_key_zone != NULL);
 
-	const knot_rrset_t *tsig = knot_packet_tsig(query);
-
-	// not required, TSIG is already found
-//	if (knot_packet_additional_rrset_count(query) > 0) {
-//		/*! \todo warning */
-//		tsig = knot_packet_additional_rrset(query,
-//		                 knot_packet_additional_rrset_count(query) - 1);
-//		if (knot_rrset_type(tsig) == KNOT_RRTYPE_TSIG) {
-//			dbg_zones_verb("found TSIG in normal query\n");
-//		} else {
-//			tsig = NULL; /* Invalidate if not TSIG RRTYPE. */
-//		}
-//	}
-
-	if (tsig == NULL) {
-		// no TSIG, this is completely valid
-		/*! \note This function is (should be) called only in case of
-		          normal query, i.e. we do not have to check ACL.
-		 */
-		*tsig_rcode = 0;
-		return KNOT_EOK;
-	}
-
 	// if there is some TSIG in the query, find the TSIG associated with
 	// the zone
 	dbg_zones_verb("Checking zone and ACL.\n");
-	int ret = zones_query_check_zone(zone, addr, tsig_key_zone, rcode,
-	                                 knot_packet_opcode(query));
+	int ret = zones_query_check_zone(zone, knot_packet_opcode(query),
+	                                 addr, tsig_key_zone, rcode);
 
 	
 	/* Accept found OR unknown key results. */
@@ -1996,15 +1887,19 @@ static int zones_check_tsig_query(const knot_zone_t *zone,
 		if (*tsig_key_zone != NULL) {
 			// everything OK, so check TSIG
 			dbg_zones_verb("Verifying TSIG.\n");
-			ret = zones_verify_tsig_query(query, tsig, *tsig_key_zone,
+			ret = zones_verify_tsig_query(query, *tsig_key_zone,
 			                              rcode, tsig_rcode,
 			                              tsig_prev_time_signed);
 		} else {
 			dbg_zones_verb("No key configured for zone.\n");
-			// no key configured for zone, return BADKEY
-			*tsig_rcode = KNOT_TSIG_RCODE_BADKEY;
-			*rcode = KNOT_RCODE_NOTAUTH;
-			ret = KNOT_TSIG_EBADKEY;
+			if (knot_packet_tsig(query)) {
+				// no key configured for zone, return BADKEY
+				dbg_zones_verb("TSIG used, but not configured "
+				               "for this zone, ret=BADKEY.\n");
+				*tsig_rcode = KNOT_TSIG_RCODE_BADKEY;
+				*rcode = KNOT_RCODE_NOTAUTH;
+				ret = KNOT_TSIG_EBADKEY;
+			}
 		}
 	}
 
@@ -2014,6 +1909,355 @@ static int zones_check_tsig_query(const knot_zone_t *zone,
 	return ret;
 }
 
+static int zones_update_forward(int fd, knot_ns_transport_t ttype,
+                                knot_zone_t *zone, const sockaddr_t *from,
+                                knot_packet_t *query, size_t qsize)
+{
+	/*! \todo #1291 #1999 This is really the same as for NOTIFY+SOA, should
+	 *        use common API. */
+
+	int ret = KNOT_EOK;
+	int orig_id = (int)knot_packet_id(query);
+	rcu_read_lock();
+	
+	zonedata_t *zd = (zonedata_t *)knot_zone_data(zone);
+	
+	/* Create socket on random port. */
+	sockaddr_t *master = &zd->xfr_in.master;
+	int stype = SOCK_DGRAM;
+	if (ttype == NS_TRANSPORT_TCP) {
+		stype = SOCK_STREAM;
+	}
+	int nfd = socket_create(master->family, stype);
+	
+	/* Check requested source. */
+	char strbuf[256] = "Generic error.";
+	sockaddr_t *via = &zd->xfr_in.via;
+	if (via->len > 0) {
+		if (bind(nfd, via->ptr, via->len) < 0) {
+			socket_close(nfd);
+			nfd = -1;
+			char r_addr[SOCKADDR_STRLEN];
+			sockaddr_tostr(via, r_addr, sizeof(r_addr));
+			snprintf(strbuf, sizeof(strbuf),
+			         "Couldn't bind to \'%s\'", r_addr);
+		}
+	}
+	
+	/* Store query as pending. */
+	knot_ns_xfr_t req;
+	memset(&req, 0, sizeof(knot_ns_xfr_t));
+	req.session = nfd;
+	req.fwd_src_fd = fd;
+	req.type = XFR_TYPE_FORWARD;
+	if (ttype == NS_TRANSPORT_TCP) {
+		req.flags |= XFR_FLAG_TCP;
+		req.send = zones_send_cb;
+	} else {
+		req.flags |= XFR_FLAG_UDP;
+		req.send = zones_send_udp;
+	}
+	req.zone = zone;
+	
+	/* Create FORWARD query and send to primary. */
+	uint8_t *rwire = malloc(qsize);
+	if (rwire) {
+		ret = knot_ns_create_forward_query(query, rwire, &qsize);
+	} else {
+		ret = KNOT_ENOMEM;
+	}
+	if (nfd > -1) {
+		/* Connect on TCP. */
+		if (ttype == NS_TRANSPORT_TCP) {
+			if (connect(nfd, master->ptr, master->len) < 0) {
+				ret = KNOT_ECONNREFUSED;
+			}
+		}
+
+		int sent = 0;
+		if (ret == KNOT_EOK) {
+			sent = req.send(nfd, master, rwire, qsize);
+		}
+	
+		/* Store ID of the awaited response. */
+		if (sent == qsize) {
+			ret = KNOT_EOK;
+		} else {
+			strbuf[0] = '\0';
+			ret = KNOT_ECONNREFUSED;
+		}
+	}
+	if (ret != KNOT_EOK) {
+		if (nfd > -1) {
+			socket_close(nfd);
+		}
+		dbg_zones("update: failed to create FORWARD qry '%s'\n",
+		          knot_strerror(ret));
+		rcu_read_unlock();
+		free(rwire);
+		return KNOT_ENOMEM;
+	}
+	free(rwire);
+
+	req.packet_nr = orig_id;
+	memcpy(&req.addr, master, sizeof(sockaddr_t));
+	memcpy(&req.saddr, from, sizeof(sockaddr_t));
+	sockaddr_update(&req.addr);
+	sockaddr_update(&req.saddr);
+	
+	/* Retain pointer to zone and issue. */
+	knot_zone_retain(req.zone);
+	if (ret == KNOT_EOK) {
+		ret = xfr_request(zd->server->xfr_h, &req);
+	}
+	if (ret != KNOT_EOK) {
+		knot_zone_release(req.zone); /* Discard */
+		log_server_warning("Failed to forward UPDATE query for zone '%s' (%s).\n",
+		                   zd->conf->name, strbuf);
+	}
+	
+	rcu_read_unlock();
+	return KNOT_EOK;
+}
+
+
+
+/*----------------------------------------------------------------------------*/
+
+static int zones_store_changesets_to_disk(knot_zone_t *zone,
+                                          knot_changesets_t *chgsets)
+{
+	journal_t *journal = zones_store_changesets_begin(zone);
+	if (journal == NULL) {
+		dbg_zones("zones: create_changesets: "
+		          "Could not start journal operation.\n");
+		return KNOT_ERROR;
+	}
+	
+	int ret = zones_store_changesets(zone, chgsets);
+	if (ret != KNOT_EOK) {
+		zones_store_changesets_rollback(journal);
+		dbg_zones("zones: create_changesets: "
+		          "Could not store in the journal. Reason: %s.\n",
+		          knot_strerror(ret));
+		
+		return ret;
+	}
+	
+	ret = zones_store_changesets_commit(journal);
+	if (ret != KNOT_EOK) {
+		dbg_zones("zones: create_changesets: "
+		          "Could not commit to journal. Reason: %s.\n",
+		          knot_strerror(ret));
+		
+		return ret;
+	}
+	
+	return KNOT_EOK;
+}
+
+/*! \brief Process UPDATE query.
+ *
+ * Functions expects that the query is already authenticated
+ * and TSIG signature is verified.
+ *
+ * \note Set parameter 'rcode' according to answering procedure.
+ * \note Function expects RCU to be locked.
+ *
+ * \retval KNOT_EOK if successful.
+ * \retval error if not.
+ */
+static int zones_process_update_auth(knot_zone_t *zone,
+                                     knot_packet_t *resp,
+                                     uint8_t *resp_wire, size_t *rsize,
+                                     knot_rcode_t *rcode,
+                                     const sockaddr_t *addr,
+                                     knot_key_t *tsig_key)
+{
+	int ret = KNOT_EOK;
+	dbg_zones_verb("TSIG check successful. Answering query.\n");
+	
+	/* Create log message prefix. */
+	char *keytag = NULL;
+	if (tsig_key) {
+		keytag = knot_dname_to_str(tsig_key->name);
+	}
+	char *r_str = xfr_remote_str(addr, keytag);
+	const char *zone_name = ((zonedata_t*)knot_zone_data(zone))->conf->name;
+	char *msg  = sprintf_alloc("UPDATE of '%s' from %s:",
+	                           zone_name, r_str ? r_str : "'unknown'");
+	free(r_str);
+	free(keytag);
+	log_zone_info("%s Started.\n", msg);
+	
+	
+	/* Reserve place for the TSIG */
+	if (tsig_key != NULL) {
+		size_t tsig_max_size = tsig_wire_maxsize(tsig_key);
+		knot_packet_set_tsig_size(resp, tsig_max_size);
+	}
+	
+	/* We must prepare a changesets_t structure even if
+	 * there is only one changeset - because of the API. */
+	knot_changesets_t *chgsets = NULL;
+	ret = knot_changeset_allocate(&chgsets, KNOT_CHANGESET_TYPE_DDNS);
+	if (ret != KNOT_EOK) {
+		*rcode = KNOT_RCODE_SERVFAIL;
+		log_zone_error("%s %s\n", msg, knot_strerror(ret));
+		free(msg);
+		return ret;
+	}
+	
+	assert(chgsets->allocated >= 1);
+	
+	/*
+	 * NEW DDNS PROCESSING -------------------------------------------------
+	 */
+	/* 1) Process the UPDATE packet, apply to zone, create changesets. */
+	
+	dbg_zones_verb("Processing UPDATE packet.\n");
+	chgsets->count = 1; /* DU is represented by a single chset. */
+	
+	knot_zone_contents_t *new_contents = NULL;
+	ret = knot_ns_process_update2(knot_packet_query(resp),
+	                              knot_zone_get_contents(zone),
+	                              &new_contents,
+	                              chgsets, rcode);
+
+	if (ret != KNOT_EOK) {
+		if (ret < 0) {
+			log_zone_error("%s %s\n", msg, knot_strerror(ret));
+		} else {
+			log_zone_notice("%s: No change to zone made.\n", msg);
+			knot_response_set_rcode(resp, KNOT_RCODE_NOERROR);
+			uint8_t *tmp_wire = NULL;
+			ret = knot_packet_to_wire(resp, &tmp_wire, rsize);
+			if (ret != KNOT_EOK) {
+				*rcode = KNOT_RCODE_SERVFAIL;
+				return ret;
+			} else {
+				memcpy(resp_wire, tmp_wire, *rsize);
+				*rcode = KNOT_RCODE_NOERROR;
+			}
+		}
+
+		knot_free_changesets(&chgsets);
+		free(msg);
+		return (ret < 0) ? ret : KNOT_EOK;
+	}
+	
+	/* 2) Store changesets, (TODO: but do not commit???). */
+	ret = zones_store_changesets_to_disk(zone, chgsets);
+	if (ret != KNOT_EOK) {
+		log_zone_error("%s %s\n", msg, knot_strerror(ret));
+		xfrin_rollback_update(zone->contents, &new_contents,
+		                      &chgsets->changes);
+		knot_free_changesets(&chgsets);
+		free(msg);
+		return ret;
+	}
+	
+	/* 3) Switch zone contents. */
+	knot_zone_retain(zone); /* Retain pointer for safe RCU unlock. */
+	rcu_read_unlock();      /* Unlock for switch. */
+	ret = xfrin_switch_zone(zone, new_contents, XFR_TYPE_UPDATE);
+	rcu_read_lock();        /* Relock */
+	knot_zone_release(zone);/* Release held pointer. */
+
+	if (ret != KNOT_EOK) {
+		log_zone_error("%s: Failed to replace current zone - %s\n",
+		               msg, knot_strerror(ret));
+		// Cleanup old and new contents
+		xfrin_rollback_update(zone->contents, &new_contents,
+		                      &chgsets->changes);
+
+		/* Free changesets, but not the data. */
+		knot_free_changesets(&chgsets);
+		return KNOT_ERROR;
+	}
+
+	/* 4) Cleanup. */
+	
+	xfrin_cleanup_successful_update(&chgsets->changes);
+	
+	/* Free changesets, but not the data. */
+	knot_free_changesets(&chgsets);
+	assert(ret == KNOT_EOK);
+	log_zone_info("%s: Finished.\n", msg);
+	
+	free(msg);
+	msg = NULL;
+	
+	/*
+	 * \NEW DDNS PROCESSING ------------------------------------------------
+	 */
+	
+	
+//	/* 1) Process the incoming packet, prepare 
+//	 *    prerequisities and changeset.
+//	 */
+//	dbg_zones_verb("Processing UPDATE packet.\n");
+//	chgsets->count = 1; /* DU is represented by a single chset. */
+//	ret = knot_ns_process_update(knot_packet_query(resp),
+//				     knot_zone_contents(zone),
+//				     &chgsets->sets[0], rcode);
+	
+//	if (ret != KNOT_EOK) {
+//		log_zone_error("%s %s\n", msg, knot_strerror(ret));
+//		knot_free_changesets(&chgsets);
+//		free(msg);
+//		return ret;
+//	}
+	
+//	/* 2) Save changeset to journal.
+//	 *    Apply changeset to zone.
+//	 *    Commit changeset to journal.
+//	 *    Switch the zone.
+//	 */
+//	knot_zone_contents_t *contents_new = NULL;
+//	knot_zone_retain(zone); /* Retain pointer for safe RCU unlock. */
+//	rcu_read_unlock();      /* Unlock for switch. */
+//	dbg_zones_verb("Storing and applying changesets.\n");
+//	ret = zones_store_and_apply_chgsets(chgsets, zone, &contents_new, msg, 
+//					    XFR_TYPE_UPDATE);
+//	rcu_read_lock();        /* Relock */
+//	knot_zone_release(zone);/* Release held pointer. */
+//	free(msg);
+//	msg = NULL;
+	
+//	/* Changesets should be freed by now. */
+//	if (ret != KNOT_EOK) {
+//		dbg_zones_verb("Storing and applying changesets failed: %s.\n",
+//			       knot_strerror(ret));
+//		*rcode = (ret == KNOT_EMALF) ? KNOT_RCODE_FORMERR
+//		                             : KNOT_RCODE_SERVFAIL;
+//		return ret;
+//	}
+
+	/* 3) Prepare DDNS response. */
+	assert(*rcode == KNOT_RCODE_NOERROR);
+	dbg_zones_verb("Preparing NOERROR UPDATE response RCODE=%u "
+		       "pkt=%p resp_wire=%p\n", *rcode, resp, resp_wire);
+	knot_response_set_rcode(resp, KNOT_RCODE_NOERROR);
+	uint8_t *tmp_wire = NULL;
+	ret = knot_packet_to_wire(resp, &tmp_wire, rsize);
+	if (ret != KNOT_EOK) {
+		dbg_zones("DDNS failed to write pkt to wire (%s). Size %zu\n",
+			  knot_strerror(ret), *rsize);
+		*rcode = KNOT_RCODE_SERVFAIL;
+		return ret;
+	} else {
+		/* This is strange, but the knot_packet_to_wire() can't write
+		 * to already existing buffer. */
+		memcpy(resp_wire, tmp_wire, *rsize);
+	}
+	
+	dbg_zones("DDNS reply rsize = %zu\n", *rsize);
+	
+	
+	return ret;
+}
+
 /*----------------------------------------------------------------------------*/
 /* API functions                                                              */
 /*----------------------------------------------------------------------------*/
@@ -2191,9 +2435,9 @@ int zones_zonefile_sync(knot_zone_t *zone, journal_t *journal)
 
 /*----------------------------------------------------------------------------*/
 
-int zones_query_check_zone(const knot_zone_t *zone, const sockaddr_t *addr,
-                           knot_key_t **tsig_key, knot_rcode_t *rcode,
-                           uint8_t q_opcode)
+int zones_query_check_zone(const knot_zone_t *zone, uint8_t q_opcode,
+                           const sockaddr_t *addr, knot_key_t **tsig_key,
+                           knot_rcode_t *rcode)
 {
 	if (addr == NULL || tsig_key == NULL || rcode == NULL) {
 		dbg_zones_verb("Wrong arguments.\n");
@@ -2212,14 +2456,20 @@ int zones_query_check_zone(const knot_zone_t *zone, const sockaddr_t *addr,
 		return KNOT_ERROR;
 	}
 
-	/* Check xfr-out ACL */
+	/* Check ACL (xfr-out for xfers, update-in for DDNS) */
+	acl_t *acl_used = zd->xfr_out;
+	if (q_opcode == KNOT_OPCODE_UPDATE) {
+		acl_used = zd->update_in;
+	}
 	acl_key_t *match = NULL;
-	if (acl_match(zd->xfr_out, addr, &match) == ACL_DENY) {
+	if (acl_match(acl_used, addr, &match) == ACL_DENY) {
 		*rcode = KNOT_RCODE_REFUSED;
 		return KNOT_EACCES;
 	} else {
 		dbg_zones("zones: authorized query or request for "
-		          "'%s %s'. match=%p\n", zd->conf->name, "XFR/OUT", match);
+		          "'%s %s'. match=%p\n", zd->conf->name,
+		          q_opcode == KNOT_OPCODE_UPDATE ? "UPDATE":"XFR/OUT",
+			  match);
 		if (match) {
 			/* Save configured TSIG key for comparison. */
 			conf_iface_t *iface = (conf_iface_t*)(match->val);
@@ -2253,12 +2503,16 @@ int zones_xfr_check_zone(knot_ns_xfr_t *xfr, knot_rcode_t *rcode)
 		return KNOT_EEXPIRED;
 	}
 
-	return zones_query_check_zone(xfr->zone, &xfr->addr, &xfr->tsig_key,
-	                              rcode, knot_packet_opcode(xfr->query));
+	return zones_query_check_zone(xfr->zone, KNOT_OPCODE_QUERY,
+	                              &xfr->addr, &xfr->tsig_key,
+	                              rcode);
 }
 
 /*----------------------------------------------------------------------------*/
-
+/*! \todo This function is here only because TSIG key is associated with the
+ *        zone via zonedata. If it was in the zone structure (which would be
+ *        IMHO ok, this whole function could be moved to nameserver.c.
+ */
 int zones_normal_query_answer(knot_nameserver_t *nameserver,
                               knot_packet_t *query, const sockaddr_t *addr,
                               uint8_t *resp_wire, size_t *rsize,
@@ -2347,10 +2601,17 @@ int zones_normal_query_answer(knot_nameserver_t *nameserver,
 			ret = KNOT_TSIG_EBADKEY;
 		} else {
 			dbg_zones_verb("Checking TSIG in query.\n");
-			ret = zones_check_tsig_query(zone, query, addr,
-			                             &rcode, &tsig_rcode,
-			                             &tsig_key_zone,
-			                             &tsig_prev_time_signed);
+			const knot_rrset_t *tsig = knot_packet_tsig(query);
+			if (tsig == NULL) {
+				// no TSIG, this is completely valid
+				tsig_rcode = 0;
+				ret = KNOT_EOK;
+			} else {
+				ret = zones_check_tsig_query(zone, query, addr,
+				                             &rcode, &tsig_rcode,
+				                             &tsig_key_zone,
+				                             &tsig_prev_time_signed);
+			}
 		}
 
 		if (ret == KNOT_EOK) {
@@ -2511,6 +2772,163 @@ int zones_normal_query_answer(knot_nameserver_t *nameserver,
 
 /*----------------------------------------------------------------------------*/
 
+int zones_process_update(knot_nameserver_t *nameserver,
+                         knot_packet_t *query, const sockaddr_t *addr,
+                         uint8_t *resp_wire, size_t *rsize,
+                         int fd, knot_ns_transport_t transport)
+{
+	rcu_read_lock();
+
+	knot_packet_t *resp = NULL;
+	knot_zone_t *zone = NULL;
+	knot_rcode_t rcode = KNOT_RCODE_NOERROR;
+	size_t rsize_max = *rsize;
+	knot_key_t *tsig_key_zone = NULL;
+	uint16_t tsig_rcode = 0;
+	uint64_t tsig_prev_time_signed = 0;
+	const knot_rrset_t *tsig_rr = NULL; 
+
+	// Parse rest of the query, prepare response, find zone
+	int ret = knot_ns_prep_update_response(nameserver, query, &resp, &zone,
+	                                       (transport == NS_TRANSPORT_TCP)
+	                                       ? *rsize : 0);
+	dbg_zones_verb("Preparing response structure = %s\n", knot_strerror(ret));
+	switch (ret) {
+	case KNOT_EOK: break;
+	case KNOT_EMALF: /* No TSIG signing in this case. */
+		rcode = KNOT_RCODE_FORMERR;
+		break;
+	default:
+		rcode = KNOT_RCODE_SERVFAIL;
+		break;
+	}
+
+	/* Check if zone is valid. */
+	const knot_zone_contents_t *contents = knot_zone_contents(zone);
+	if (zone && (knot_zone_flags(zone) & KNOT_ZONE_DISCARDED)) {
+		rcode = KNOT_RCODE_SERVFAIL; /* It's ok, temporarily. */
+		tsig_rcode = KNOT_TSIG_RCODE_BADKEY;
+		ret = KNOT_ENOZONE;
+	} else if (!zone || !contents) {     /* Treat as BADKEY. */
+		rcode = KNOT_RCODE_NOTAUTH;
+		tsig_rcode = KNOT_TSIG_RCODE_BADKEY;
+		ret = KNOT_TSIG_EBADKEY;
+		dbg_zones_verb("No zone or empty, refusing UPDATE.\n");
+	}
+
+	/* Verify TSIG if it is in the packet. */
+	tsig_rr = knot_packet_tsig(query);
+	if (ret == KNOT_EOK) { /* Have valid zone to check ACLs against. */
+		dbg_zones_verb("Checking TSIG in query.\n");
+		ret = zones_check_tsig_query(zone, query, addr,
+					     &rcode, &tsig_rcode,
+					     &tsig_key_zone,
+					     &tsig_prev_time_signed);
+	}
+
+	/* Allow pass-through of an unknown TSIG in DDNS forwarding (must have zone). */
+	if (zone && (ret == KNOT_EOK || (ret == KNOT_TSIG_EBADKEY && !tsig_key_zone))) {
+		/* Transaction is authenticated (or unprotected)
+		 * and zone has primary master set,
+		 * proceed to forward the query to the next hop.
+		 */
+		zonedata_t *zd = (zonedata_t *)knot_zone_data(zone);
+		if (zd->xfr_in.has_master) {
+			ret = zones_update_forward(fd, transport, zone, addr,
+			                           query, *rsize);
+			*rsize = 0; /* Do not send reply immediately. */
+			knot_packet_free(&resp);
+			rcu_read_unlock();
+			return ret;
+		}
+	}
+	
+	/*
+	 * 1) DDNS Zone Section check (RFC2136, Section 3.1).
+	 */
+	if (ret == KNOT_EOK) {
+		ret = knot_ddns_check_zone(contents, query, &rcode);
+		dbg_zones_verb("Checking zone = %s\n", knot_strerror(ret));
+	}
+
+	/*
+	 * 2) DDNS Prerequisities Section processing (RFC2136, Section 3.2).
+	 *
+	 * \note Permissions section means probably policies and fine grained
+	 *       access control, not transaction security.
+	 */
+	knot_ddns_prereq_t *prereqs = NULL;
+	if (ret == KNOT_EOK) {
+		ret = knot_ddns_process_prereqs(query, &prereqs, &rcode);
+		dbg_zones_verb("Processing prereq = %s\n", knot_strerror(ret));
+	}
+	if (ret == KNOT_EOK) {
+		assert(prereqs != NULL);
+		ret = knot_ddns_check_prereqs(contents, &prereqs, &rcode);
+		dbg_zones_verb("Checking prereq = %s\n", knot_strerror(ret));
+		knot_ddns_prereqs_free(&prereqs);
+	}
+
+	/*
+	 * 3) Process query.
+	*/
+	if (ret == KNOT_EOK) {
+		zonedata_t *zd = (zonedata_t *)knot_zone_data(zone);
+		pthread_mutex_lock(&zd->xfr_in.lock);
+
+		/*! \note This function expects RCU locked. */
+		ret = zones_process_update_auth(zone, resp, resp_wire, rsize,
+		                                &rcode, addr, tsig_key_zone);
+		dbg_zones_verb("Auth, update_proc = %s\n", knot_strerror(ret));
+		
+		pthread_mutex_unlock(&zd->xfr_in.lock);
+	}
+
+	/* Create error query if processing failed. */
+	if (ret != KNOT_EOK) {
+		ret = knot_ns_error_response_from_query(nameserver,
+		                                        query, rcode,
+		                                        resp_wire, rsize);
+	}
+	
+	/* No response, no signing required or FORMERR. */
+	if (*rsize == 0 || !tsig_rr || rcode == KNOT_RCODE_FORMERR) {
+		knot_packet_free(&resp);
+		rcu_read_unlock();
+		return ret;
+	}
+	
+	/* Just add TSIG RR on most errors. */
+	if (tsig_rcode != 0 && tsig_rcode != KNOT_TSIG_RCODE_BADTIME) {
+		ret = knot_tsig_add(resp_wire, rsize, rsize_max,
+		                    tsig_rcode, tsig_rr);
+		dbg_zones_verb("Adding TSIG = %s\n", knot_strerror(ret));
+	} else if (tsig_key_zone) {
+		dbg_zones_verb("Signing message with TSIG.\n");
+		size_t digest_len = tsig_alg_digest_length(tsig_key_zone->algorithm);
+		uint8_t *digest = (uint8_t *)malloc(digest_len);
+		if (digest == NULL) {
+			knot_packet_free(&resp);
+			rcu_read_unlock();
+			return KNOT_ENOMEM;
+		}
+		ret = knot_tsig_sign(resp_wire,
+				     rsize, rsize_max,
+				     tsig_rdata_mac(tsig_rr),
+				     tsig_rdata_mac_length(tsig_rr),
+				     digest, &digest_len, tsig_key_zone,
+				     tsig_rcode, tsig_prev_time_signed);
+		free(digest);
+	}
+
+	knot_packet_free(&resp);
+	rcu_read_unlock();
+
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
 int zones_process_response(knot_nameserver_t *nameserver, 
                            sockaddr_t *from,
                            knot_packet_t *packet, uint8_t *response_wire,
@@ -2988,7 +3406,9 @@ int zones_changeset_binary_size(const knot_changeset_t *chgset, size_t *size)
 	}
 
 	/*! \todo How is the changeset serialized? Any other parts? */
-	*size += soa_from_size + soa_to_size + remove_size + add_size;
+	*size = soa_from_size + soa_to_size + remove_size + add_size;
+	/* + Changeset flags. */
+	*size += sizeof(uint32_t);
 
 	return KNOT_EOK;
 }
@@ -3014,6 +3434,11 @@ static int zones_rrset_write_to_mem(const knot_rrset_t *rr, char **entry,
 static int zones_serialize_and_store_chgset(const knot_changeset_t *chs,
                                             char *entry, size_t max_size)
 {
+	/* Write changeset flags. */
+	memcpy(entry, (char*)&chs->flags, sizeof(uint32_t));
+	entry += sizeof(uint32_t);
+	max_size -= sizeof(uint32_t);
+	
 	/* Serialize SOA 'from'. */
 	int ret = zones_rrset_write_to_mem(chs->soa_from, &entry, &max_size);
 	if (ret != KNOT_EOK) {
@@ -3146,14 +3571,14 @@ static int zones_store_changeset(const knot_changeset_t *chs, journal_t *j,
 
 /*----------------------------------------------------------------------------*/
 
-journal_t *zones_store_changesets_begin(knot_ns_xfr_t *xfr)
+journal_t *zones_store_changesets_begin(knot_zone_t *zone)
 {
-	if (xfr == NULL || xfr->data == NULL || xfr->zone == NULL) {
+	if (zone == NULL) {
 		return NULL;
 	}
 
 	/* Fetch zone-specific data. */
-	knot_zone_t *zone = xfr->zone;
+	//knot_zone_t *zone = xfr->zone;
 	zonedata_t *zd = (zonedata_t *)zone->data;
 	if (!zd->ixfr_db) {
 		return NULL;
@@ -3197,14 +3622,14 @@ int zones_store_changesets_rollback(journal_t *j)
 
 /*----------------------------------------------------------------------------*/
 
-int zones_store_changesets(knot_ns_xfr_t *xfr)
+int zones_store_changesets(knot_zone_t *zone, knot_changesets_t *src)
 {
-	if (xfr == NULL || xfr->data == NULL || xfr->zone == NULL) {
+	if (zone == NULL || src == NULL) {
 		return KNOT_EINVAL;
 	}
 
-	knot_zone_t *zone = xfr->zone;
-	knot_changesets_t *src = (knot_changesets_t *)xfr->data;
+//	knot_zone_t *zone = xfr->zone;
+//	knot_changesets_t *src = (knot_changesets_t *)xfr->data;
 
 	/* Fetch zone-specific data. */
 	zonedata_t *zd = (zonedata_t *)zone->data;
@@ -3318,14 +3743,14 @@ int zones_create_and_save_changesets(const knot_zone_t *old_zone,
 	}
 	
 	xfr.data = changesets;
-	journal_t *journal = zones_store_changesets_begin(&xfr);
+	journal_t *journal = zones_store_changesets_begin(xfr.zone);
 	if (journal == NULL) {
 		dbg_zones("zones: create_changesets: "
 		          "Could not start journal operation.\n");
 		return KNOT_ERROR;
 	}
 	
-	ret = zones_store_changesets(&xfr);
+	ret = zones_store_changesets(xfr.zone, (knot_changesets_t *)xfr.data);
 	if (ret != KNOT_EOK) {
 		zones_store_changesets_rollback(journal);
 		dbg_zones("zones: create_changesets: "
@@ -3351,6 +3776,81 @@ int zones_create_and_save_changesets(const knot_zone_t *old_zone,
 
 /*----------------------------------------------------------------------------*/
 
+int zones_store_and_apply_chgsets(knot_changesets_t *chs,
+                                  knot_zone_t *zone,
+                                  knot_zone_contents_t **new_contents,
+                                  const char *msgpref, int type)
+{
+	int ret = KNOT_EOK;
+	int apply_ret = KNOT_EOK;
+	int switch_ret = KNOT_EOK;
+
+	/* Serialize and store changesets. */
+	dbg_xfr("xfr: IXFR/IN serializing and saving changesets\n");
+	journal_t *transaction = zones_store_changesets_begin(zone);
+	if (transaction != NULL) {
+		ret = zones_store_changesets(zone, chs);
+	} else {
+		ret = KNOT_ERROR;
+	}
+	if (ret != KNOT_EOK) {
+		log_zone_error("%s Failed to serialize and store "
+		               "changesets - %s\n", msgpref,
+		               knot_strerror(ret));
+		/* Free changesets, but not the data. */
+		knot_free_changesets(&chs);
+		return ret;
+	}
+
+	/* Now, try to apply the changesets to the zone. */
+	apply_ret = xfrin_apply_changesets(zone, chs, new_contents);
+
+	if (apply_ret != KNOT_EOK) {
+		zones_store_changesets_rollback(transaction);
+		log_zone_error("%s Failed to apply changesets - %s\n",
+		               msgpref, knot_strerror(apply_ret));
+
+		/* Free changesets, but not the data. */
+		knot_free_changesets(&chs);
+		return apply_ret;  // propagate the error above
+	}
+
+	/* Commit transaction. */
+	ret = zones_store_changesets_commit(transaction);
+	if (ret != KNOT_EOK) {
+		/*! \todo THIS WILL LEAK!! xfrin_rollback_update() needed. */
+		log_zone_error("%s Failed to commit stored changesets "
+		               "- %s\n", msgpref, knot_strerror(apply_ret));
+		knot_free_changesets(&chs);
+		return ret;
+	}
+
+	/* Switch zone contents. */
+	switch_ret = xfrin_switch_zone(zone, *new_contents, type);
+
+	if (switch_ret != KNOT_EOK) {
+		log_zone_error("%s Failed to replace current zone - %s\n",
+		               msgpref, knot_strerror(switch_ret));
+		// Cleanup old and new contents
+		xfrin_rollback_update(zone->contents, new_contents,
+		                      &chs->changes);
+
+		/* Free changesets, but not the data. */
+		knot_free_changesets(&chs);
+		return KNOT_ERROR;
+	}
+
+	xfrin_cleanup_successful_update(&chs->changes);
+
+	/* Free changesets, but not the data. */
+	knot_free_changesets(&chs);
+	assert(ret == KNOT_EOK);
+	log_zone_info("%s Finished.\n", msgpref);
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
 int zones_timers_update(knot_zone_t *zone, conf_zone_t *cfzone, evsched_t *sch)
 {
 	if (!sch || !zone) {
@@ -3387,7 +3887,7 @@ int zones_timers_update(knot_zone_t *zone, conf_zone_t *cfzone, evsched_t *sch)
 
 	/* Check XFR/IN master server. */
 	rcu_read_lock();
-	if (zd->xfr_in.master.ptr) {
+	if (zd->xfr_in.has_master) {
 
 		/* Schedule REFRESH timer. */
 		uint32_t refresh_tmr = 0;
@@ -3513,3 +4013,139 @@ int zones_cancel_notify(zonedata_t *zd, notify_ev_t *ev)
 	free(ev);
 	return KNOT_EOK;
 }
+
+int zones_process_update_response(knot_ns_xfr_t *data, uint8_t *rwire, size_t *rsize)
+{
+	/* Processing of a forwarded response:
+	 * change packet id
+	 */
+	int ret = KNOT_EOK;
+	knot_wire_set_id(rwire, (uint16_t)data->packet_nr);
+
+	/* Forward the response. */
+	ret = data->send(data->fwd_src_fd, &data->saddr, rwire, *rsize);
+	if (ret != *rsize) {
+		ret = KNOT_ECONN;
+	} else {
+		ret = KNOT_EOK;
+	}
+	
+	/* As it is a response, do not reply back. */
+	*rsize = 0;
+	return ret;
+}
+
+
+int zones_verify_tsig_query(const knot_packet_t *query,
+                            const knot_key_t *key,
+                            knot_rcode_t *rcode, uint16_t *tsig_rcode,
+                            uint64_t *tsig_prev_time_signed)
+{
+	assert(key != NULL);
+	assert(rcode != NULL);
+	assert(tsig_rcode != NULL);
+	
+	const knot_rrset_t *tsig_rr = knot_packet_tsig(query);
+	if (tsig_rr == NULL) {
+		dbg_zones("TSIG key required, but not in query - REFUSED.\n");
+		*rcode = KNOT_RCODE_REFUSED;
+		return KNOT_TSIG_EBADKEY;
+	}
+
+	/*
+	 * 1) Check if we support the requested algorithm.
+	 */
+	tsig_algorithm_t alg = tsig_rdata_alg(tsig_rr);
+	if (tsig_alg_digest_length(alg) == 0) {
+		log_answer_info("Unsupported digest algorithm "
+		                "requested, treating as bad key\n");
+		/*! \todo [TSIG] It is unclear from RFC if I
+		 *               should treat is as a bad key
+		 *               or some other error.
+		 */
+		*rcode = KNOT_RCODE_NOTAUTH;
+		*tsig_rcode = KNOT_TSIG_RCODE_BADKEY;
+		return KNOT_TSIG_EBADKEY;
+	}
+
+	const knot_dname_t *kname = knot_rrset_owner(tsig_rr);
+	assert(kname != NULL);
+
+	/*
+	 * 2) Find the particular key used by the TSIG.
+	 *    Check not only name, but also the algorithm.
+	 */
+	if (key && kname && knot_dname_compare(key->name, kname) == 0
+	    && key->algorithm == alg) {
+		dbg_zones_verb("Found claimed TSIG key for comparison\n");
+	} else {
+		*rcode = KNOT_RCODE_NOTAUTH;
+		*tsig_rcode = KNOT_TSIG_RCODE_BADKEY;
+		return KNOT_TSIG_EBADKEY;
+	}
+
+	/*
+	 * 3) Validate the query with TSIG.
+	 */
+	/* Prepare variables for TSIG */
+	/*! \todo These need to be saved to the response somehow. */
+	//size_t tsig_size = tsig_wire_maxsize(key);
+	size_t digest_max_size = tsig_alg_digest_length(key->algorithm);
+	//size_t digest_size = 0;
+	//uint64_t tsig_prev_time_signed = 0;
+	//uint8_t *digest = (uint8_t *)malloc(digest_max_size);
+	//memset(digest, 0 , digest_max_size);
+
+	/* Copy MAC from query. */
+	dbg_zones_verb("Validating TSIG from query\n");
+
+	//const uint8_t* mac = tsig_rdata_mac(tsig_rr);
+	size_t mac_len = tsig_rdata_mac_length(tsig_rr);
+
+	int ret = KNOT_EOK;
+
+	if (mac_len > digest_max_size) {
+		*rcode = KNOT_RCODE_FORMERR;
+		dbg_zones("MAC length %zu exceeds digest "
+		       "maximum size %zu\n", mac_len, digest_max_size);
+		return KNOT_EMALF;
+	} else {
+		//memcpy(digest, mac, mac_len);
+		//digest_size = mac_len;
+
+		/* Check query TSIG. */
+		ret = knot_tsig_server_check(tsig_rr,
+		                             knot_packet_wireformat(query),
+		                             knot_packet_size(query), key);
+		dbg_zones_verb("knot_tsig_server_check() returned %s\n",
+		               knot_strerror(ret));
+
+		/* Evaluate TSIG check results. */
+		switch(ret) {
+		case KNOT_EOK:
+			*rcode = KNOT_RCODE_NOERROR;
+			break;
+		case KNOT_TSIG_EBADKEY:
+			*tsig_rcode = KNOT_TSIG_RCODE_BADKEY;
+			*rcode = KNOT_RCODE_NOTAUTH;
+			break;
+		case KNOT_TSIG_EBADSIG:
+			*tsig_rcode = KNOT_TSIG_RCODE_BADSIG;
+			*rcode = KNOT_RCODE_NOTAUTH;
+			break;
+		case KNOT_TSIG_EBADTIME:
+			*tsig_rcode = KNOT_TSIG_RCODE_BADTIME;
+			// store the time signed from the query
+			*tsig_prev_time_signed = tsig_rdata_time_signed(tsig_rr);
+			*rcode = KNOT_RCODE_NOTAUTH;
+			break;
+		case KNOT_EMALF:
+			*rcode = KNOT_RCODE_FORMERR;
+			break;
+		default:
+			*rcode = KNOT_RCODE_SERVFAIL;
+		}
+	}
+
+	return ret;
+}
diff --git a/src/knot/server/zones.h b/src/knot/server/zones.h
index 1ed724c..89834a6 100644
--- a/src/knot/server/zones.h
+++ b/src/knot/server/zones.h
@@ -64,6 +64,7 @@ typedef struct zonedata_t
 	acl_t *xfr_out;    /*!< ACL for xfr-out.*/
 	acl_t *notify_in;  /*!< ACL for notify-in.*/
 	acl_t *notify_out; /*!< ACL for notify-out.*/
+	acl_t *update_in; /*!< ACL for notify-out.*/
 
 	/*! \brief XFR-IN scheduler. */
 	struct {
@@ -78,13 +79,11 @@ typedef struct zonedata_t
 		int next_id;             /*!< ID of the next awaited SOA resp.*/
 		uint32_t bootstrap_retry;/*!< AXFR/IN bootstrap retry. */
 		unsigned       scheduled;/*!< Scheduled operations. */ 
+		int has_master;          /*!< True if it has master set. */
 	} xfr_in;
 
 	/*! \brief List of pending NOTIFY events. */
 	list notify_pending;
-	
-	/*! \brief List of fds with pending SOA queries. */
-	int soa_pending;
 
 	/*! \brief Zone IXFR history. */
 	journal_t *ixfr_db;
@@ -138,9 +137,9 @@ int zones_zonefile_sync(knot_zone_t *zone, journal_t *journal);
 /*!
  * \todo Document me.
  */
-int zones_query_check_zone(const knot_zone_t *zone, const sockaddr_t *addr,
-                           knot_key_t **tsig_key, knot_rcode_t *rcode,
-                           uint8_t q_opcode);
+int zones_query_check_zone(const knot_zone_t *zone, uint8_t q_opcode,
+                           const sockaddr_t *addr, knot_key_t **tsig_key,
+                           knot_rcode_t *rcode);
 
 /*!
  * \todo Document me.
@@ -156,6 +155,14 @@ int zones_normal_query_answer(knot_nameserver_t *nameserver,
                               knot_ns_transport_t transport);
 
 /*!
+ * \todo Document me.
+ */
+int zones_process_update(knot_nameserver_t *nameserver,
+                         knot_packet_t *query, const sockaddr_t *addr,
+                         uint8_t *resp_wire, size_t *rsize,
+                         int fd, knot_ns_transport_t transport);
+
+/*!
  * \brief Processes normal response packet.
  *
  * \param nameserver Name server structure to provide the needed data.
@@ -215,7 +222,7 @@ int zones_ns_conf_hook(const struct conf_t *conf, void *data);
  * \todo Expects the xfr structure to be initialized in some way.
  * \todo Update documentation!!!
  */
-int zones_store_changesets(knot_ns_xfr_t *xfr);
+int zones_store_changesets(knot_zone_t *zone, knot_changesets_t *src);
 
 /*!
  * \brief Begin changesets storing transaction.
@@ -223,7 +230,7 @@ int zones_store_changesets(knot_ns_xfr_t *xfr);
  * \retval pointer to journal if successful
  * \retval NULL on failure.
  */
-journal_t *zones_store_changesets_begin(knot_ns_xfr_t *xfr);
+journal_t *zones_store_changesets_begin(knot_zone_t *zone);
 
 /*!
  * \brief Commit stored changesets.
@@ -289,6 +296,11 @@ int zones_xfr_load_changesets(knot_ns_xfr_t *xfr, uint32_t serial_from,
 int zones_create_and_save_changesets(const knot_zone_t *old_zone,
                                      const knot_zone_t *new_zone);
 
+int zones_store_and_apply_chgsets(knot_changesets_t *chs,
+                                  knot_zone_t *zone,
+                                  knot_zone_contents_t **new_contents,
+                                  const char *msgpref, int type);
+
 /*!
  * \brief Update zone timers.
  *
@@ -319,6 +331,28 @@ int zones_timers_update(knot_zone_t *zone, conf_zone_t *cfzone, evsched_t *sch);
  */
 int zones_cancel_notify(zonedata_t *zd, notify_ev_t *ev);
 
+
+/*!
+ * \brief Processes forwarded UPDATE response packet.
+ * \todo #1291 move to appropriate section (DDNS).
+ */
+int zones_process_update_response(knot_ns_xfr_t *data, uint8_t *rwire, size_t *rsize);
+
+/*!
+ * \brief Verify TSIG in query.
+ *
+ * \param query Query packet.
+ * \param key TSIG key used for this query.
+ * \param rcode Dst for resulting RCODE.
+ * \param tsig_rcode Dst for resulting TSIG RCODE.
+ * \param tsig_prev_time_signed Dst for previout time signed.
+ *
+ * \return KNOT_EOK if verified or error if not.
+ */
+int zones_verify_tsig_query(const knot_packet_t *query,
+                            const knot_key_t *key,
+                            knot_rcode_t *rcode, uint16_t *tsig_rcode,
+                            uint64_t *tsig_prev_time_signed);
 #endif // _KNOTD_ZONES_H_
 
 /*! @} */
diff --git a/src/knot/zone/semantic-check.c b/src/knot/zone/semantic-check.c
index a9f9af2..43c1893 100644
--- a/src/knot/zone/semantic-check.c
+++ b/src/knot/zone/semantic-check.c
@@ -969,15 +969,17 @@ static int check_nsec3_node_in_zone(knot_zone_contents_t *zone, knot_node_t *nod
 		return KNOT_EOK;
 	}
 
-	if (((real_size = base32hex_encode_alloc(((char *)
-		rdata_item_data(&(nsec3_rrset->rdata->items[4]))) + 1,
+	if (((b32_ret = base32hex_encode_alloc((uint8_t *)
+		(rdata_item_data(&(nsec3_rrset->rdata->items[4]))) + 1,
 		rdata_item_size(&nsec3_rrset->rdata->items[4]) - 1,
-		(char **)&next_dname_decoded)) <= 0) ||
+		&next_dname_decoded)) <= 0) ||
 		(next_dname_decoded == NULL)) {
 		fprintf(stderr, "Could not encode base32 string!\n");
 		return KNOT_ERROR;
 	}
 
+	real_size = b32_ret;
+
 	/* This is why we allocate maximum length of decoded string + 1 */
 //	memmove(next_dname_decoded + 1, next_dname_decoded, real_size);
 //	next_dname_decoded[0] = real_size;
@@ -1522,7 +1524,7 @@ void log_cyclic_errors_in_zone(err_handler_t *handler,
 		if (((b32_ret = base32hex_encode_alloc(((uint8_t *)
 			rdata_item_data(&(nsec3_rrset->rdata->items[4]))) + 1,
 			rdata_item_size(&nsec3_rrset->rdata->items[4]) - 1,
-			(char **)&next_dname_decoded)) <= 0) ||
+			&next_dname_decoded)) <= 0) ||
 			(next_dname_decoded == NULL)) {
 			fprintf(stderr, "Could not encode base32 string!\n");
 			err_handler_handle_error(handler, last_nsec3_node,
@@ -1530,6 +1532,8 @@ void log_cyclic_errors_in_zone(err_handler_t *handler,
 			return;
 		}
 
+		real_size = b32_ret;
+
 		/* Local allocation, will be discarded. */
 		knot_dname_t *next_dname =
 			knot_dname_new_from_str((char *)next_dname_decoded,
diff --git a/src/knot/zone/zone-dump-text.c b/src/knot/zone/zone-dump-text.c
index bf02ea1..f231a70 100644
--- a/src/knot/zone/zone-dump-text.c
+++ b/src/knot/zone/zone-dump-text.c
@@ -549,25 +549,33 @@ static char *rdata_time_to_string(knot_rdata_item_t item)
 
 static char *rdata_base32_to_string(knot_rdata_item_t item)
 {
-	int length;
+	char *ret = NULL;
 	size_t size = rdata_item_size(item);
+
 	if (size == 0) {
-		char *ret = malloc(sizeof(char) * 2);
+		ret = malloc(2);
+
 		ret[0] = '-';
 		ret[1] = '\0';
-		return ret;
-	}
-
-	size -= 1; // remove length byte from count
-	char *ret = NULL;
-	length = base32hex_encode_alloc((char *)rdata_item_data(item) + 1,
-	                                size, &ret);
-	if (length > 0) {
-		return ret;
 	} else {
-		free(ret);
-		return NULL;
+		int32_t  b32_out;
+		uint32_t out_len = ((size + 4) / 5) * 8;
+
+		ret = malloc(out_len + 1);
+
+		b32_out = base32hex_encode(rdata_item_data(item) + 1,
+					   size - 1,
+					   (uint8_t *)ret,
+					   out_len);
+		if (b32_out <= 0) {
+			free(ret);
+			ret = NULL;
+		}
+
+		ret[b32_out] = '\0';
 	}
+
+	return ret;
 }
 
 /*!< \todo Replace with function from .../common after release. */
diff --git a/src/knot/zone/zone-dump.c b/src/knot/zone/zone-dump.c
index b9c7bc2..97e8a57 100644
--- a/src/knot/zone/zone-dump.c
+++ b/src/knot/zone/zone-dump.c
@@ -110,7 +110,7 @@ static int write_wrapper(const void *src,
 		return KNOT_EINVAL;
 	}
 	
-	dbg_zdump_detail("zdump: write_wrapper: Writing %d bytes to fd: %d.\n",
+	dbg_zdump_detail("zdump: write_wrapper: Writing %zu bytes to fd: %d.\n",
 	                 size * n, fd);
 	
 	if (fd < 0) {
@@ -133,7 +133,7 @@ static int write_wrapper(const void *src,
 		/* Write to buffer first, if possible. */
 		if (*written_bytes + (size * n) < BUFFER_SIZE) {
 			dbg_zdump_detail("zdump: write_wrapper: Fits to "
-			                 "buffer. Remaining=%d.\n",
+			                 "buffer. Remaining=%lu.\n",
 			                 BUFFER_SIZE - *written_bytes);
 			int ret = write_to_stream(src, size, n,
 			                          stream,
@@ -154,7 +154,7 @@ static int write_wrapper(const void *src,
 			size_t remainder = BUFFER_SIZE - *written_bytes;
 			dbg_zdump_detail("zdump: write_wrapper: "
 			                 "Flushing buffer, "
-			                 "appending %d bytes.\n", remainder);
+			                 "appending %zu bytes.\n", remainder);
 			int ret = write_to_stream(src, 1,
 			                          remainder,
 			                          stream,
@@ -187,7 +187,7 @@ static int write_wrapper(const void *src,
 			if ((size * n) - remainder > BUFFER_SIZE) {
 				/* Write through. */
 				dbg_zdump("zdump: Attempting buffer write "
-				          "through. Total: %d bytes.\n",
+				          "through. Total: %zu bytes.\n",
 				          (size * n) - remainder);
 				ret = write_to_file_crc(src + remainder, 1,
 				                        (size * n) - remainder,
diff --git a/src/knot/zone/zone-load.c b/src/knot/zone/zone-load.c
index 28195f8..9973d75 100644
--- a/src/knot/zone/zone-load.c
+++ b/src/knot/zone/zone-load.c
@@ -450,7 +450,7 @@ static knot_rdata_t *knot_load_rdata(uint16_t type, FILE *f,
 	int ret = knot_rdata_set_items(rdata, items, rdata_count);
 	if (ret != KNOT_EOK) {
 		dbg_zload("zload: read_rdata: Could not set items "
-		          "when loading rdata. Reason: %\n.",
+		          "when loading rdata. Reason: %s\n.",
 		          knot_strerror(ret));
 		load_rdata_purge(rdata, items, desc->length, desc, type);
 		return NULL;
diff --git a/src/knotc.8 b/src/knotc.8
index f08642e..ba345ce 100644
--- a/src/knotc.8
+++ b/src/knotc.8
@@ -1,10 +1,10 @@
-.TH knotc "8" "September 2012" "CZ.NIC Labs" "Knot DNS, version 1.1.3"
+.TH knotc "8" "September 2012" "CZ.NIC Labs" "Knot DNS, version 1.2-rc2"
 .SH NAME
 .B knotc
 \- Knot DNS control utility
 .SH SYNOPSIS
 .B knotc
-[\fIparameters\fR] \fIstart|stop|restart|reload|running|compile\fR
+[\fIparameters\fR] \fI<action>\fR [\fIaction_args\fR]
 .SH DESCRIPTION
 .SS "Parameters:"
 .HP
@@ -13,6 +13,16 @@
 \fB\-j\fR [num], \fB\-\-jobs\fR=\fI[num]\fR
 Number of parallel tasks to run (only for 'compile').
 .TP
+\fB\-s\fR [server]\fR Remote server address (default 127.0.0.1) 
+.TP
+\fB\-p\fR [port]\fR Remote server port (default 5553)
+.TP
+\fB\-y\fR [hmac:]name:key]\fR Use key_id for specified on the command line.
+.TP
+\fB\-k\fR [file]\fR Use key file (as in config section 'keys'). 
+f.e. echo "knotc-key hmac-md5 Wg==" > knotc.key
+If you omit algorithm, hmac-md5 will be used as default.
+.TP
 \fB\-f\fR, \fB\-\-force\fR
 Force operation \- override some checks.
 .TP
@@ -47,20 +57,39 @@ Stops and then starts knot server daemon.
 reload
 Reload knot configuration and compiled zones.
 .TP
-running
+flush
+Flush journal and update zone files.
+.TP
+status
 Check if server is running.
 .TP
 compile
 Compile zone file.
 .TP
 refresh
-Refresh all slave zones.
+Refresh slave zones (all if not specified).
 .TP
 checkconf
 Check server configuration.
 .TP
 checkzone
 Check zones before compiling (accepts specific zones, f.e. 'knotc checkzone example1.com example2.com').
+.SS "EXAMPLES" 
+.TP
+.B Setup a keyfile for remote control
+.TP
+1. Generate keys 
+dnssec-keygen -a hmac-md5 -b 256 -n HOST knotc-key
+.TP
+2. Extract secret in base64 format and create keyfile
+echo "knotc-key hmac-md5 <secret>" > knotc.key
+
+Make sure the key can be read/written only by owner for
+security reasons.
+.TP
+
+.B Reload server remotely
+knotc -s 127.0.0.1 -k knotc.key reload
 .SH "SEE ALSO"
 The full documentation for
 .B Knot
diff --git a/src/knotd.8 b/src/knotd.8
index f57b5a5..4c96cff 100644
--- a/src/knotd.8
+++ b/src/knotd.8
@@ -1,4 +1,4 @@
-.TH "knotd" "8" "September 2012" "CZ.NIC Labs" "Knot DNS, version 1.1.3"
+.TH "knotd" "8" "September 2012" "CZ.NIC Labs" "Knot DNS, version 1.2-rc2"
 .SH NAME
 .B knotd
 \- Knot DNS daemon
diff --git a/src/libknot/consts.h b/src/libknot/consts.h
index 4249763..3431bc3 100644
--- a/src/libknot/consts.h
+++ b/src/libknot/consts.h
@@ -57,7 +57,8 @@ typedef enum knot_packet_type {
 	KNOT_RESPONSE_NORMAL, /*!< Normal response. */
 	KNOT_RESPONSE_AXFR,   /*!< AXFR transfer response. */
 	KNOT_RESPONSE_IXFR,   /*!< IXFR transfer response. */
-	KNOT_RESPONSE_NOTIFY  /*!< NOTIFY response. */
+	KNOT_RESPONSE_NOTIFY, /*!< NOTIFY response. */
+	KNOT_RESPONSE_UPDATE  /*!< Dynamic update response. */
 } knot_packet_type_t;
 
 /*
diff --git a/src/libknot/dname.c b/src/libknot/dname.c
index eed2fd6..5c7e961 100644
--- a/src/libknot/dname.c
+++ b/src/libknot/dname.c
@@ -178,8 +178,13 @@ static int knot_dname_str_to_wire(const char *name, uint size,
 
 	while (ch - (const uint8_t *)name < size) {
 		assert(w - wire - 1 == ch - (const uint8_t *)name);
-
+		
 		if (*ch == '.') {
+			/* Zero-length label inside a dname - invalid. */
+			if (label_length == 0) {
+				free(wire);
+				return -1;
+			}
 			dbg_dname_detail("Position %zd (%p): "
 			                 "label length: %u\n",
 			                 label_start - wire,
@@ -262,6 +267,11 @@ static int knot_dname_find_labels(knot_dname_t *dname, int alloc)
 	short label_count = 0;
 
 	while (pos - name < size && *pos != '\0' && label_count < KNOT_MAX_DNAME_LABELS ) {
+		if (*pos > 63) { /* Check label lengths. */
+			dbg_dname("Wrong wire format of domain name!\n");
+			dbg_dname("Label %d exceeds 63 bytes.\n", label_count);
+			return -1;
+		}
 		labels[label_count++] = pos - name;
 		pos += *pos + 1;
 	}
@@ -471,8 +481,9 @@ knot_dname_t *knot_dname_new_from_wire(const uint8_t *name, uint size,
 /*----------------------------------------------------------------------------*/
 
 knot_dname_t *knot_dname_parse_from_wire(const uint8_t *wire,
-                                             size_t *pos, size_t size,
-                                             knot_node_t *node)
+                                         size_t *pos, size_t size,
+                                         knot_node_t *node,
+                                         knot_dname_t *dname)
 {
 	uint8_t name[KNOT_MAX_DNAME_LENGTH];
 	uint8_t labels[KNOT_MAX_DNAME_LABELS];
@@ -539,34 +550,30 @@ knot_dname_t *knot_dname_parse_from_wire(const uint8_t *wire,
 		*pos += 1;
 	}
 
-	knot_dname_t *dname = knot_dname_new();
+	/* Allocate if NULL. */
+	if (dname == NULL) {
+		dname = knot_dname_new();
+		if (dname) {
+			dname->name = (uint8_t *)malloc((i + 1) * sizeof(uint8_t));
+			dname->labels = (uint8_t *)malloc((l + 1) * sizeof(uint8_t));
+		}
+	}
 
 	if (dname == NULL) {
 		ERR_ALLOC_FAILED;
 		return NULL;
 	}
 
-	dname->name = (uint8_t *)malloc((i + 1) * sizeof(uint8_t));
-	if (dname->name == NULL) {
+	if (dname->name == NULL || dname->labels == NULL) {
 		ERR_ALLOC_FAILED;
 		knot_dname_free(&dname);
 		return NULL;
 	}
 
 	memcpy(dname->name, name, i + 1);
-	dname->size = i + 1;
-
-	/*! \todo Why l + 1 ?? */
-	dname->labels = (uint8_t *)malloc((l + 1) * sizeof(uint8_t));
-	if (dname->labels == NULL) {
-		ERR_ALLOC_FAILED;
-		knot_dname_free(&dname);
-		return NULL;
-	}
 	memcpy(dname->labels, labels, l + 1);
-
+	dname->size = i + 1;
 	dname->label_count = l;
-
 	dname->node = node;
 
 	return dname;
diff --git a/src/libknot/dname.h b/src/libknot/dname.h
index 347e699..6f649ce 100644
--- a/src/libknot/dname.h
+++ b/src/libknot/dname.h
@@ -124,9 +124,22 @@ knot_dname_t *knot_dname_new_from_wire(const uint8_t *name,
                                            unsigned int size,
                                            struct knot_node *node);
 
+/*!
+ * \brief Parse dname from wire.
+ *
+ * \param wire Message in wire format.
+ * \param pos Position of the domain name on wire.
+ * \param size Domain name length.
+ * \param node Zone node the domain name belongs to. Set to NULL if not
+ *             applicable.
+ * \param dname Destination dname (will allocate new when NULL).
+ *
+ * \return parsed domain name or NULL.
+ */
 knot_dname_t *knot_dname_parse_from_wire(const uint8_t *wire,
-                                             size_t *pos, size_t size,
-                                             struct knot_node *node);
+                                         size_t *pos, size_t size,
+                                         struct knot_node *node,
+                                         knot_dname_t *dname);
 
 /*!
  * \brief Initializes domain name by the name given in wire format.
diff --git a/src/libknot/hash/cuckoo-hash-table.c b/src/libknot/hash/cuckoo-hash-table.c
index 7358e14..7d454a9 100644
--- a/src/libknot/hash/cuckoo-hash-table.c
+++ b/src/libknot/hash/cuckoo-hash-table.c
@@ -1434,7 +1434,7 @@ int ck_deep_copy(ck_hash_table_t *from, ck_hash_table_t **to)
 			return -2;
 		}
 
-		dbg_ck_detail("Copying stash item: %p with item %p, ", si,
+		dbg_ck_detail("Copying stash item: %p with item %p.\n", si,
 		              si->item);
 
 		if (si->item == NULL) {
@@ -1473,9 +1473,10 @@ dbg_ck_exec_detail(
 		              (si_new) ? si_new->item : NULL);
 
 		assert(si_new != NULL);
-		assert(si_new->item != NULL);
-		dbg_ck_detail("key: %.*s\n", (int)si_new->item->key_length,
-		              si_new->item->key);
+		if (si_new->item != NULL) {
+			dbg_ck_detail("key: %.*s\n", (int)si_new->item->key_length,
+			              si_new->item->key);
+		}
 );
 	}
 
diff --git a/src/libknot/nameserver/name-server.c b/src/libknot/nameserver/name-server.c
index 0a7a298..8238d7e 100644
--- a/src/libknot/nameserver/name-server.c
+++ b/src/libknot/nameserver/name-server.c
@@ -2950,7 +2950,7 @@ static int ns_ixfr(knot_ns_xfr_t *xfr)
 /*----------------------------------------------------------------------------*/
 
 static int knot_ns_prepare_response(knot_packet_t *query, knot_packet_t **resp,
-                                    size_t max_size)
+                                    size_t max_size, int copy_question)
 {
 	assert(max_size >= 500);
 	
@@ -2969,7 +2969,7 @@ static int knot_ns_prepare_response(knot_packet_t *query, knot_packet_t **resp,
 		return ret;
 	}
 
-	ret = knot_response_init_from_query(*resp, query);
+	ret = knot_response_init_from_query(*resp, query, copy_question);
 
 	if (ret != KNOT_EOK) {
 		dbg_ns("Failed to init response structure.\n");
@@ -3207,7 +3207,7 @@ int knot_ns_parse_packet(const uint8_t *query_wire, size_t qsize,
 		if(knot_packet_is_query(packet)) {
 			*type = KNOT_QUERY_UPDATE;
 		} else {
-			return KNOT_RCODE_FORMERR;
+			*type = KNOT_RESPONSE_UPDATE;
 		}
 		break;
 	default:
@@ -3437,7 +3437,7 @@ int knot_ns_prep_normal_response(knot_nameserver_t *nameserver,
 		resp_max_size = MAX_UDP_PAYLOAD;
 	}
 
-	ret = knot_ns_prepare_response(query, resp, resp_max_size);
+	ret = knot_ns_prepare_response(query, resp, resp_max_size, 1);
 	if (ret != KNOT_EOK) {
 		return KNOT_ERROR;
 	}
@@ -3487,6 +3487,143 @@ dbg_ns_exec_verb(
 
 /*----------------------------------------------------------------------------*/
 
+int knot_ns_prep_update_response(knot_nameserver_t *nameserver,
+                                 knot_packet_t *query, knot_packet_t **resp,
+                                 knot_zone_t **zone, size_t max_size)
+{
+	dbg_ns_verb("knot_ns_prep_update_response()\n");
+
+	if (nameserver == NULL || query == NULL || resp == NULL
+	    || zone == NULL) {
+		return KNOT_EINVAL;
+	}
+
+	// first, parse the rest of the packet
+	assert(knot_packet_is_query(query));
+	dbg_ns_verb("Query - parsed: %zu, total wire size: %zu\n",
+	            knot_packet_parsed(query), knot_packet_size(query));
+	int ret;
+
+	ret = knot_packet_parse_rest(query);
+	if (ret != KNOT_EOK) {
+		dbg_ns("Failed to parse rest of the query: %s.\n",
+		       knot_strerror(ret));
+		return ret;
+	}
+
+	/*
+	 * Semantic checks
+	 *
+	 * Check the QDCOUNT and in case of anything but 1 send back
+	 * FORMERR
+	 */
+	if (knot_packet_qdcount(query) != 1) {
+		dbg_ns("QDCOUNT != 1. Reply FORMERR.\n");
+		return KNOT_EMALF;
+	}
+
+	/*
+	 * Check what is in the Additional section. Only OPT and TSIG are
+	 * allowed. TSIG must be the last record if present.
+	 */
+	/*! \todo Put to separate function - used in prep_normal_response(). */
+	if (knot_packet_arcount(query) > 0) {
+		int ok = 0;
+		const knot_rrset_t *add1 =
+		                knot_packet_additional_rrset(query, 0);
+		if (knot_packet_additional_rrset_count(query) == 1
+		    && (knot_rrset_type(add1) == KNOT_RRTYPE_OPT
+		        || knot_rrset_type(add1) == KNOT_RRTYPE_TSIG)) {
+			ok = 1;
+		} else if (knot_packet_additional_rrset_count(query) == 2) {
+			const knot_rrset_t *add2 =
+			                knot_packet_additional_rrset(query, 1);
+			if (knot_rrset_type(add1) == KNOT_RRTYPE_OPT
+			    && knot_rrset_type(add2) == KNOT_RRTYPE_TSIG) {
+				ok = 1;
+			}
+		}
+
+		if (!ok) {
+			dbg_ns("Additional section malformed. Reply FORMERR\n");
+			return KNOT_EMALF;
+		}
+	}
+
+	size_t resp_max_size = 0;
+
+	knot_packet_dump(query);
+
+	/*! \todo Put to separate function - used in prep_normal_response(). */
+	if (max_size > 0) {
+		// if TCP is used, buffer size is the only constraint
+		assert(max_size > 0);
+		resp_max_size = max_size;
+	} else if (knot_query_edns_supported(query)) {
+		assert(max_size == 0);
+		if (knot_edns_get_payload(&query->opt_rr) <
+		    knot_edns_get_payload(nameserver->opt_rr)) {
+			resp_max_size = knot_edns_get_payload(&query->opt_rr);
+		} else {
+			resp_max_size = knot_edns_get_payload(
+						nameserver->opt_rr);
+		}
+	}
+
+	if (resp_max_size < MAX_UDP_PAYLOAD) {
+		resp_max_size = MAX_UDP_PAYLOAD;
+	}
+
+	ret = knot_ns_prepare_response(query, resp, resp_max_size, 0);
+	if (ret != KNOT_EOK) {
+		return KNOT_ERROR;
+	}
+
+	dbg_ns_verb("Query - parsed: %zu, total wire size: %zu\n",
+	            query->parsed, query->size);
+	dbg_ns_detail("Opt RR: version: %d, payload: %d\n",
+	              query->opt_rr.version, query->opt_rr.payload);
+
+	// get the answer for the query
+	knot_zonedb_t *zonedb = rcu_dereference(nameserver->zone_db);
+
+	dbg_ns_detail("EDNS supported in query: %d\n",
+	              knot_query_edns_supported(query));
+
+	// set the OPT RR to the response
+	if (knot_query_edns_supported(query)) {
+		ret = knot_response_add_opt(*resp, nameserver->opt_rr, 1,
+		                            knot_query_nsid_requested(query));
+		if (ret != KNOT_EOK) {
+			dbg_ns("Failed to set OPT RR to the response"
+			       ": %s\n", knot_strerror(ret));
+		} else {
+			// copy the DO bit from the query
+			if (knot_query_dnssec_requested(query)) {
+				knot_edns_set_do(&(*resp)->opt_rr);
+			}
+		}
+	}
+
+	dbg_ns_verb("Response max size: %zu\n", (*resp)->max_size);
+
+	const knot_dname_t *qname = knot_packet_qname(knot_packet_query(*resp));
+	assert(qname != NULL);
+
+//	uint16_t qtype = knot_packet_qtype(*resp);
+dbg_ns_exec_verb(
+	char *name_str = knot_dname_to_str(qname);
+	dbg_ns_verb("Trying to find zone %s\n", name_str);
+	free(name_str);
+);
+	// find zone
+	*zone = knot_zonedb_find_zone(zonedb, qname);
+
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
 int knot_ns_answer_normal(knot_nameserver_t *nameserver, 
                           const knot_zone_t *zone, knot_packet_t *resp,
                           uint8_t *response_wire, size_t *rsize, int check_any)
@@ -3619,7 +3756,7 @@ dbg_ns_exec_verb(
 	response->wireformat = xfr->wire;
 	response->max_size = xfr->wire_size;
 
-	ret = knot_response_init_from_query(response, xfr->query);
+	ret = knot_response_init_from_query(response, xfr->query, 1);
 
 	if (ret != KNOT_EOK) {
 		dbg_ns("Failed to init response structure.\n");
@@ -3796,8 +3933,9 @@ int knot_ns_answer_axfr(knot_nameserver_t *nameserver, knot_ns_xfr_t *xfr)
 	if (ret < 0 && ret != KNOT_ECONN) {
 		dbg_ns("AXFR failed, sending SERVFAIL.\n");
 		// now only one type of error (SERVFAIL), later maybe more
-		/*! \todo xfr->wire is not NULL, will fail on assert! */
-		knot_ns_xfr_send_error(nameserver, xfr, KNOT_RCODE_SERVFAIL);
+		knot_ns_error_response_from_query(nameserver, xfr->query,
+		                                  KNOT_RCODE_SERVFAIL,
+		                                  xfr->wire, &xfr->wire_size);
 		ret = xfr->send(xfr->session, &xfr->addr, xfr->wire, 
 		                xfr->wire_size);
 	} else if (ret > 0) {
@@ -4076,143 +4214,140 @@ int knot_ns_process_ixfrin(knot_nameserver_t *nameserver,
 }
 
 /*----------------------------------------------------------------------------*/
-
-int knot_ns_process_update(knot_nameserver_t *nameserver, knot_packet_t *query,
-                           uint8_t *response_wire, size_t *rsize,
-                           knot_zone_t **zone, knot_changeset_t **changeset)
+/*
+ * The given query is already fully parsed. But the parameter contains an 
+ * already prepared response structure. 
+ *
+ * This function should process the contents, prepare prerequisities, prepare
+ * changeset and return to the caller.
+ */
+int knot_ns_process_update(const knot_packet_t *query, 
+                           const knot_zone_contents_t *zone, 
+                           knot_changeset_t *changeset, knot_rcode_t *rcode)
 {
-	// 1) Parse the rest of the packet
 	assert(knot_packet_is_query(query));
 
-	knot_packet_t *response;
-	assert(*rsize >= MAX_UDP_PAYLOAD);
-	int ret = knot_ns_prepare_response(query, &response, MAX_UDP_PAYLOAD);
-	if (ret != KNOT_EOK) {
-		knot_ns_error_response_from_query(nameserver, query,
-		                                  KNOT_RCODE_SERVFAIL,
-		                                  response_wire, rsize);
-		return KNOT_EOK;
-	}
-
-	assert(response != NULL);
+	dbg_ns("Processing Dynamic Update.\n");
 
-	dbg_ns_verb("Query - parsed: %zu, total wire size: %zu\n",
-	            query->parsed, query->size);
-
-	if (knot_packet_parsed(query) < knot_packet_size(query)) {
-		ret = knot_packet_parse_rest(query);
-		if (ret != KNOT_EOK) {
-			dbg_ns("Failed to parse rest of the query: "
-			       "%s.\n", knot_strerror(ret));
-			knot_ns_error_response_full(nameserver, response,
-			                            (ret == KNOT_EMALF)
-			                               ? KNOT_RCODE_FORMERR
-			                               : KNOT_RCODE_SERVFAIL,
-			                            response_wire, rsize);
-			knot_packet_free(&response);
-			return KNOT_EOK;
-		}
+	*rcode = KNOT_RCODE_NOERROR;
+	
+	// 1) Check zone
+	// Already done
+//	dbg_ns_verb("Checking zone for DDNS.\n");
+//	int ret = knot_ddns_check_zone(zone, query, rcode);
+//	if (ret != KNOT_EOK) {
+//		dbg_ns("Failed to check zone for update: "
+//		       "%s.\n", knot_strerror(ret));
+//		return ret;
+//	}
+
+	// 2) Convert prerequisities
+	// Already done
+//	dbg_ns_verb("Processing prerequisities.\n");
+//	knot_ddns_prereq_t *prereqs = NULL;
+//	int ret = knot_ddns_process_prereqs(query, &prereqs, rcode);
+//	if (ret != KNOT_EOK) {
+//		dbg_ns("Failed to check zone for update: "
+//		       "%s.\n", knot_strerror(ret));
+//		return ret;
+//	}
+
+//	assert(prereqs != NULL);
+
+	// 3) Check prerequisities
+	/*! \todo Somehow ensure the zone will not be changed until the update
+	 *        is finished.
+	 */
+	// Already done
+//	dbg_ns_verb("Checking prerequisities.\n");
+//	ret = knot_ddns_check_prereqs(zone, &prereqs, rcode);
+//	if (ret != KNOT_EOK) {
+//		knot_ddns_prereqs_free(&prereqs);
+//		dbg_ns("Failed to check zone for update: "
+//		       "%s.\n", knot_strerror(ret));
+//		return ret;
+//	}
+
+	// 4) Convert update to changeset
+	dbg_ns_verb("Converting UPDATE packet to changeset.\n");
+	int ret = knot_ddns_process_update(zone, query, changeset, rcode);
+	if (ret != KNOT_EOK) {
+		dbg_ns("Failed to check zone for update: "
+		       "%s.\n", knot_strerror(ret));
+		return ret;
 	}
 
-	dbg_ns_verb("Query - parsed: %zu, total wire size: %zu\n",
-	            knot_packet_parsed(query), knot_packet_size(query));
+	assert(changeset != NULL);
 
-	/*! \todo API for EDNS values. */
-	dbg_ns_verb("Opt RR: version: %d, payload: %d\n",
-	            query->opt_rr.version, query->opt_rr.payload);
-
-	// 2) Find zone for the query
-	// we do not check if there is only one entry in the Question section
-	// because the packet structure does not allow it
-	if (knot_packet_qtype(query) != KNOT_RRTYPE_SOA) {
-		dbg_ns("Question is not of type SOA.\n");
-		knot_ns_error_response_full(nameserver, response,
-		                            KNOT_RCODE_FORMERR,
-		                            response_wire, rsize);
-		knot_packet_free(&response);
-		return KNOT_EOK;
-	}
+	// Done in zones.c
+//	knot_ddns_prereqs_free(&prereqs);
+	return ret;
+}
 
-	*zone = knot_zonedb_find_zone(nameserver->zone_db,
-	                            knot_packet_qname(query));
-	if (*zone == NULL) {
-		dbg_ns("Zone not found for the update.\n");
-		knot_ns_error_response_full(nameserver, response,
-		                            KNOT_RCODE_NOTAUTH,
-		                            response_wire, rsize);
-		knot_packet_free(&response);
-		return KNOT_EOK;
+/*----------------------------------------------------------------------------*/
+/*
+ * This function should:
+ * 1) Create zone shallow copy and the changes structure.
+ * 2) Call knot_ddns_process_update2().
+ *    - If something went bad, call xfrin_rollback_update() and return an error.
+ *    - If everything went OK, continue.
+ * 3) Finalize the updated zone.
+ *
+ * NOTE: Mostly copied from xfrin_apply_changesets(). Should be refactored in 
+ *       order to get rid of duplicate code.
+ */
+int knot_ns_process_update2(const knot_packet_t *query, 
+                            knot_zone_contents_t *old_contents, 
+                            knot_zone_contents_t **new_contents, 
+                            knot_changesets_t *chgs, knot_rcode_t *rcode)
+{
+	/*! \todo Implement. */
+	if (query == NULL || old_contents == NULL || chgs == NULL ||
+	    chgs->sets == NULL || new_contents == NULL || rcode == NULL) {
+		return KNOT_EINVAL;
 	}
 
-	uint8_t rcode = 0;
-	// 3) Check zone
-	ret = knot_ddns_check_zone(*zone, query, &rcode);
-	if (ret == KNOT_EBADZONE) {
-		// zone is slave, forward the request
-		/*! \todo Implement forwarding. */
-		return KNOT_EBADZONE;
-	} else if (ret != KNOT_EOK) {
-		dbg_ns("Failed to check zone for update: "
-		       "%s.\n", knot_strerror(ret));
-		knot_ns_error_response_full(nameserver, response, rcode,
-		                            response_wire, rsize);
-		knot_packet_free(&response);
-		return KNOT_EOK;
-	}
+	dbg_ns("Applying UPDATE to zone...\n");
 
-	// 4) Convert prerequisities
-	knot_ddns_prereq_t *prereqs = NULL;
-	ret = knot_ddns_process_prereqs(query, &prereqs, &rcode);
+	/* 1) Create zone shallow copy. */
+	dbg_ns_verb("Creating shallow copy of the zone...\n");
+	knot_zone_contents_t *contents_copy = NULL;
+	knot_changes_t *changes = NULL;
+	int ret = xfrin_prepare_zone_copy(old_contents, &contents_copy,
+	                                  &changes);
 	if (ret != KNOT_EOK) {
-		dbg_ns("Failed to check zone for update: "
-		       "%s.\n", knot_strerror(ret));
-		knot_ns_error_response_full(nameserver, response, rcode,
-		                            response_wire, rsize);
-		knot_packet_free(&response);
-		return KNOT_EOK;
+		dbg_ns("Failed to prepare zone copy: %s\n",
+		          knot_strerror(ret));
+		*rcode = KNOT_RCODE_SERVFAIL;
+		return ret;
 	}
-
-	assert(prereqs != NULL);
-
-	// 5) Check prerequisities
-	/*! \todo Somehow ensure the zone will not be changed until the update
-	 *        is finished.
-	 */
-	ret = knot_ddns_check_prereqs(knot_zone_contents(*zone), &prereqs,
-	                              &rcode);
+	
+	/* 2) Apply the UPDATE and create changesets. */
+	dbg_ns_verb("Applying the UPDATE and creating changeset...\n");
+	ret = knot_ddns_process_update2(contents_copy, query, &chgs->sets[0], 
+	                                changes, rcode);
 	if (ret != KNOT_EOK) {
-		dbg_ns("Failed to check zone for update: "
-		       "%s.\n", knot_strerror(ret));
-		knot_ns_error_response_full(nameserver, response, rcode,
-		                            response_wire, rsize);
-		knot_ddns_prereqs_free(&prereqs);
-		knot_packet_free(&response);
-		return KNOT_EOK;
+		dbg_ns("Failed to apply UPDATE to the zone copy or no update"
+		       " made: %s\n", (ret < 0) ? knot_strerror(ret)
+		                                : "No change made.");
+		xfrin_rollback_update(old_contents, &contents_copy, &changes);
+		return ret;
 	}
-
-	// 6) Convert update to changeset
-	ret = knot_ddns_process_update(query, changeset, &rcode);
+	
+	dbg_ns_verb("Finalizing updated zone...\n");
+	ret = xfrin_finalize_updated_zone(contents_copy, changes, old_contents);
 	if (ret != KNOT_EOK) {
-		dbg_ns("Failed to check zone for update: "
-		       "%s.\n", knot_strerror(ret));
-		knot_ns_error_response_full(nameserver, response, rcode,
-		                            response_wire, rsize);
-		knot_ddns_prereqs_free(&prereqs);
-		knot_packet_free(&response);
-		return KNOT_EOK;
+		dbg_ns("Failed to finalize updated zone: %s\n",
+		       knot_strerror(ret));
+		xfrin_rollback_update(old_contents, &contents_copy, &changes);
+		*rcode = (ret == KNOT_EMALF) ? KNOT_RCODE_FORMERR
+		                             : KNOT_RCODE_SERVFAIL;
+		return ret;
 	}
 
-	assert(changeset != NULL);
-
-	// 7) Create response
-	dbg_ns("Update converted successfuly.\n");
-
-	/*! \todo No response yet. Distinguish somehow in the caller.
-	 *        Maybe only this case will be EOK, other cases some error.
-	 */
-
-	knot_ddns_prereqs_free(&prereqs);
-	knot_packet_free(&response);
+	chgs->changes = changes;
+	*new_contents = contents_copy;
+	
 	return KNOT_EOK;
 }
 
@@ -4221,7 +4356,10 @@ int knot_ns_process_update(knot_nameserver_t *nameserver, knot_packet_t *query,
 int knot_ns_create_forward_query(const knot_packet_t *query,
                                  uint8_t *query_wire, size_t *size)
 {
-	// just copy the wireformat of the query and set a new random ID to it
+	/* Forward UPDATE query:
+	 * assign a new packet id
+	 */
+	int ret = KNOT_EOK;
 	if (knot_packet_size(query) > *size) {
 		return KNOT_ESPACE;
 	}
@@ -4229,10 +4367,9 @@ int knot_ns_create_forward_query(const knot_packet_t *query,
 	memcpy(query_wire, knot_packet_wireformat(query),
 	       knot_packet_size(query));
 	*size = knot_packet_size(query);
-
 	knot_wire_set_id(query_wire, knot_random_id());
 
-	return KNOT_EOK;
+	return ret;
 }
 
 /*----------------------------------------------------------------------------*/
diff --git a/src/libknot/nameserver/name-server.h b/src/libknot/nameserver/name-server.h
index 3fe1210..6bb7a86 100644
--- a/src/libknot/nameserver/name-server.h
+++ b/src/libknot/nameserver/name-server.h
@@ -121,6 +121,9 @@ typedef struct knot_ns_xfr {
 	uint8_t *digest;     /*!< Buffer for counting digest. */
 	size_t digest_size;  /*!< Size of the digest. */
 	size_t digest_max_size; /*!< Size of the buffer. */
+	
+	/*! \note [DDNS] Update forwarding fields. */
+	int fwd_src_fd;           /*!< Query originator fd. */
 
 	uint16_t tsig_rcode;
 	uint64_t tsig_prev_time_signed;
@@ -158,12 +161,14 @@ typedef enum knot_ns_transport {
  */
 typedef enum knot_ns_xfr_type_t {
 	/* DNS events. */
-	XFR_TYPE_AIN = 1 << 0,   /*!< AXFR-IN request (start transfer). */
-	XFR_TYPE_AOUT= 1 << 1,  /*!< AXFR-OUT request (incoming transfer). */
-	XFR_TYPE_IIN = 1 << 2,   /*!< IXFR-IN request (start transfer). */
-	XFR_TYPE_IOUT = 1 << 3,  /*!< IXFR-OUT request (incoming transfer). */
-	XFR_TYPE_SOA = 1 << 4,   /*!< Pending SOA request. */
-	XFR_TYPE_NOTIFY = 1 << 5 /*!< Pending NOTIFY query. */
+	XFR_TYPE_AIN = 1 << 0,    /*!< AXFR-IN request (start transfer). */
+	XFR_TYPE_AOUT= 1 << 1,    /*!< AXFR-OUT request (incoming transfer). */
+	XFR_TYPE_IIN = 1 << 2,    /*!< IXFR-IN request (start transfer). */
+	XFR_TYPE_IOUT = 1 << 3,   /*!< IXFR-OUT request (incoming transfer). */
+	XFR_TYPE_SOA = 1 << 4,    /*!< Pending SOA request. */
+	XFR_TYPE_NOTIFY = 1 << 5, /*!< Pending NOTIFY query. */
+	XFR_TYPE_UPDATE = 1 << 6, /*!< UPDATE request (incoming UPDATE). */
+	XFR_TYPE_FORWARD = 1 << 7 /*!< UPDATE forward request. */
 } knot_ns_xfr_type_t;
 
 /*----------------------------------------------------------------------------*/
@@ -227,6 +232,10 @@ int knot_ns_prep_normal_response(knot_nameserver_t *nameserver,
                                  knot_packet_t *query, knot_packet_t **resp,
                                  const knot_zone_t **zone, size_t max_size);
 
+int knot_ns_prep_update_response(knot_nameserver_t *nameserver,
+                                 knot_packet_t *query, knot_packet_t **resp,
+                                 knot_zone_t **zone, size_t max_size);
+
 /*!
  * \brief Creates a response for the given normal query using the data of the
  *        nameserver.
@@ -339,9 +348,14 @@ int knot_ns_switch_zone(knot_nameserver_t *nameserver,
 int knot_ns_process_ixfrin(knot_nameserver_t *nameserver, 
                              knot_ns_xfr_t *xfr);
 
-int knot_ns_process_update(knot_nameserver_t *nameserver, knot_packet_t *query,
-                           uint8_t *response_wire, size_t *rsize,
-                           knot_zone_t **zone, knot_changeset_t **changeset);
+int knot_ns_process_update(const knot_packet_t *query, 
+                           const knot_zone_contents_t *zone, 
+                           knot_changeset_t *changeset, knot_rcode_t *rcode);
+
+int knot_ns_process_update2(const knot_packet_t *query, 
+                            knot_zone_contents_t *old_contents, 
+                            knot_zone_contents_t **new_contents, 
+                            knot_changesets_t *chgs, knot_rcode_t *rcode);
 
 int knot_ns_create_forward_query(const knot_packet_t *query,
                                  uint8_t *query_wire, size_t *size);
diff --git a/src/libknot/packet/packet.c b/src/libknot/packet/packet.c
index 6a047fb..9b7e7c7 100644
--- a/src/libknot/packet/packet.c
+++ b/src/libknot/packet/packet.c
@@ -291,22 +291,25 @@ static int knot_packet_parse_question(const uint8_t *wire, size_t *pos,
 	dbg_packet_verb("Parsing dname starting on position %zu and "
 	                      "%zu bytes long.\n", *pos, i - *pos + 1);
 	dbg_packet_verb("Alloc: %d\n", alloc);
+	size_t bp = *pos;
 	if (alloc) {
-		question->qname = knot_dname_new_from_wire(
-				wire + *pos, i - *pos + 1, NULL);
+		question->qname = knot_dname_parse_from_wire(wire, pos,
+		                                             i + 1,
+		                                             NULL, NULL);
 		if (question->qname == NULL) {
 			return KNOT_ENOMEM;
 		}
 	} else {
-		int res = knot_dname_from_wire(wire + *pos, i - *pos + 1,
-	                                         NULL, question->qname);
-		if (res != KNOT_EOK) {
-			assert(res != KNOT_EINVAL);
-			return res;
+		void *parsed = knot_dname_parse_from_wire(wire, pos,
+		                                     i + 1,
+	                                             NULL, question->qname);
+		if (!parsed) {
+			return KNOT_EMALF;
 		}
 	}
-
-	*pos = i + 1;
+	if (*pos != i + 1) {
+		dbg_packet("Parsed dname expected len=%zu, parsed=%zu.\n", i+1-bp, *pos-bp);
+	}
 	question->qtype = knot_wire_read_u16(wire + i + 1);
 	question->qclass = knot_wire_read_u16(wire + i + 3);
 	*pos += 4;
@@ -386,7 +389,7 @@ static knot_rrset_t *knot_packet_parse_rr(const uint8_t *wire, size_t *pos,
 	           *pos, size);
 
 	knot_dname_t *owner = knot_dname_parse_from_wire(wire, pos, size,
-	                                                     NULL);
+	                                                     NULL, NULL);
 	dbg_packet_detail("Created owner: %p, actual position: %zu\n", owner,
 	                  *pos);
 	if (owner == NULL) {
@@ -512,7 +515,7 @@ dbg_packet_exec_detail(
 			free(name);
 );
 
-			if (knot_rrset_compare((*rrsets)[i], rrset,
+			if (knot_rrset_match((*rrsets)[i], rrset,
 			                         KNOT_RRSET_COMPARE_HEADER)) {
 				/*! \todo Test this!!! */
 				// no duplicate checking here, the packet should
@@ -1257,7 +1260,7 @@ const knot_rrset_t *knot_packet_answer_rrset(
 /*----------------------------------------------------------------------------*/
 
 const knot_rrset_t *knot_packet_authority_rrset(
-	knot_packet_t *packet, short pos)
+	const knot_packet_t *packet, short pos)
 {
 	if (packet == NULL || pos > packet->ns_rrsets) {
 		return NULL;
@@ -1269,7 +1272,7 @@ const knot_rrset_t *knot_packet_authority_rrset(
 /*----------------------------------------------------------------------------*/
 
 const knot_rrset_t *knot_packet_additional_rrset(
-    knot_packet_t *packet, short pos)
+    const knot_packet_t *packet, short pos)
 {
 	if (packet == NULL || pos > packet->ar_rrsets) {
 		return NULL;
@@ -1289,19 +1292,19 @@ int knot_packet_contains(const knot_packet_t *packet,
 	}
 
 	for (int i = 0; i < packet->an_rrsets; ++i) {
-		if (knot_rrset_compare(packet->answer[i], rrset, cmp)) {
+		if (knot_rrset_match(packet->answer[i], rrset, cmp)) {
 			return 1;
 		}
 	}
 
 	for (int i = 0; i < packet->ns_rrsets; ++i) {
-		if (knot_rrset_compare(packet->authority[i], rrset, cmp)) {
+		if (knot_rrset_match(packet->authority[i], rrset, cmp)) {
 			return 1;
 		}
 	}
 
 	for (int i = 0; i < packet->ar_rrsets; ++i) {
-		if (knot_rrset_compare(packet->additional[i], rrset, cmp)) {
+		if (knot_rrset_match(packet->additional[i], rrset, cmp)) {
 			return 1;
 		}
 	}
@@ -1390,7 +1393,7 @@ void knot_packet_header_to_wire(const knot_header_t *header,
 
 int knot_packet_question_to_wire(knot_packet_t *packet)
 {
-	if (packet == NULL) {
+	if (packet == NULL || packet->question.qname == NULL) {
 		return KNOT_EINVAL;
 	}
 
@@ -1551,6 +1554,10 @@ void knot_packet_dump(const knot_packet_t *packet)
 	       knot_wire_flags_get_ra(packet->header.flags2) ? "ra" : "",
 	       knot_wire_flags_get_ad(packet->header.flags2) ? "ad" : "",
 	       knot_wire_flags_get_cd(packet->header.flags2) ? "cd" : "");
+	dbg_packet("  RCODE: %u\n", knot_wire_flags_get_rcode(
+	                   packet->header.flags2));
+	dbg_packet("  OPCODE: %u\n", knot_wire_flags_get_opcode(
+	                   packet->header.flags1));
 	dbg_packet("  QDCOUNT: %u\n", packet->header.qdcount);
 	dbg_packet("  ANCOUNT: %u\n", packet->header.ancount);
 	dbg_packet("  NSCOUNT: %u\n", packet->header.nscount);
diff --git a/src/libknot/packet/packet.h b/src/libknot/packet/packet.h
index 522ae8e..5a95bae 100644
--- a/src/libknot/packet/packet.h
+++ b/src/libknot/packet/packet.h
@@ -451,7 +451,7 @@ const knot_rrset_t *knot_packet_answer_rrset(
  *         or NULL if there is no such RRSet.
  */
 const knot_rrset_t *knot_packet_authority_rrset(
-	knot_packet_t *packet, short pos);
+	const knot_packet_t *packet, short pos);
 
 /*!
  * \brief Returns the requested Additional RRset.
@@ -465,7 +465,7 @@ const knot_rrset_t *knot_packet_authority_rrset(
  *         or NULL if there is no such RRSet.
  */
 const knot_rrset_t *knot_packet_additional_rrset(
-    knot_packet_t *packet, short pos);
+	const knot_packet_t *packet, short pos);
 
 /*!
  * \brief Checks if the packet already contains the given RRSet.
diff --git a/src/libknot/packet/query.h b/src/libknot/packet/query.h
index cda72b9..3ca4fd3 100644
--- a/src/libknot/packet/query.h
+++ b/src/libknot/packet/query.h
@@ -81,6 +81,8 @@ int knot_query_set_opcode(knot_packet_t *query, uint8_t opcode);
 int knot_query_add_rrset_authority(knot_packet_t *query,
                                    const knot_rrset_t *rrset);
 
+int knot_query_rr_to_wire(const knot_rrset_t *rrset, const knot_rdata_t *rdata,
+			  uint8_t **wire, uint8_t *endp);
 
 #endif /* _KNOT_QUERY_H_ */
 
diff --git a/src/libknot/packet/response.c b/src/libknot/packet/response.c
index c6a1a09..476c6b3 100644
--- a/src/libknot/packet/response.c
+++ b/src/libknot/packet/response.c
@@ -903,7 +903,8 @@ int knot_response_init(knot_packet_t *response)
 /*----------------------------------------------------------------------------*/
 
 int knot_response_init_from_query(knot_packet_t *response,
-                                    knot_packet_t *query)
+                                  knot_packet_t *query,
+                                  int copy_question)
 {
 
 	if (response == NULL || query == NULL) {
@@ -913,21 +914,29 @@ int knot_response_init_from_query(knot_packet_t *response,
 	// copy the header from the query
 	memcpy(&response->header, &query->header, sizeof(knot_header_t));
 
-	// copy the Question section (but do not copy the QNAME)
-	memcpy(&response->question, &query->question,
-	       sizeof(knot_question_t));
-
 	int err = 0;
-	// put the qname into the compression table
-	// TODO: get rid of the numeric constants
-	if ((err = knot_response_store_dname_pos(&response->compression,
-	              response->question.qname, 0, 12, 12, 0)) != KNOT_EOK) {
-		return err;
-	}
+	/*! \todo Constant. */
+	size_t to_copy = 12;
+
+	if (copy_question) {
+		// copy the Question section (but do not copy the QNAME)
+		memcpy(&response->question, &query->question,
+		       sizeof(knot_question_t));
+
+		// put the qname into the compression table
+		// TODO: get rid of the numeric constants
+		if ((err = knot_response_store_dname_pos(&response->compression,
+			      response->question.qname, 0, 12, 12, 0))
+		                != KNOT_EOK) {
+			return err;
+		}
 
-	// copy the wireformat of Header and Question from the query
-	// TODO: get rid of the numeric constants
-	size_t to_copy = 12 + 4 + knot_dname_size(response->question.qname);
+		/*! \todo Constant. */
+		to_copy += 4 + knot_dname_size(response->question.qname);
+	} else {
+		response->header.qdcount = 0;
+		knot_wire_set_qdcount(response->wireformat, 0);
+	}
 
 	assert(response->max_size >= to_copy);
 	memcpy(response->wireformat, query->wireformat, to_copy);
diff --git a/src/libknot/packet/response.h b/src/libknot/packet/response.h
index beb1a59..277b1aa 100644
--- a/src/libknot/packet/response.h
+++ b/src/libknot/packet/response.h
@@ -62,7 +62,8 @@ int knot_response_init(knot_packet_t *response);
  * \retval KNOT_EOK
  */
 int knot_response_init_from_query(knot_packet_t *response,
-                                    knot_packet_t *query);
+                                  knot_packet_t *query,
+                                  int copy_question);
 
 /*!
  * \brief Clears the response structure for reuse.
diff --git a/src/libknot/rdata.c b/src/libknot/rdata.c
index 9bcdbe5..352bb6c 100644
--- a/src/libknot/rdata.c
+++ b/src/libknot/rdata.c
@@ -242,7 +242,7 @@ int knot_rdata_from_wire(knot_rdata_t *rdata, const uint8_t *wire,
 		case KNOT_RDATA_WF_LITERAL_DNAME:
 			pos2 = *pos;
 			dname = knot_dname_parse_from_wire(
-				wire, &pos2, total_size, NULL);
+				wire, &pos2, total_size, NULL, NULL);
 			if (dname == NULL) {
 				free(items);
 				return KNOT_ERROR;
@@ -308,7 +308,7 @@ int knot_rdata_from_wire(knot_rdata_t *rdata, const uint8_t *wire,
 			case 3:
 				pos2 = *pos;
 				dname = knot_dname_parse_from_wire(
-					         wire, &pos2, total_size, NULL);
+					   wire, &pos2, total_size, NULL, NULL);
 				if (dname == NULL) {
 					knot_rdata_free_items(items, i,
 					                      desc->type, 1);
@@ -698,6 +698,18 @@ int64_t knot_rdata_soa_serial(const knot_rdata_t *rdata)
 }
 
 /*---------------------------------------------------------------------------*/
+void knot_rdata_soa_serial_set(knot_rdata_t *rdata, uint32_t serial)
+{
+	if (!rdata || rdata->count < 3) {
+		return;
+	}
+
+	// the number is in network byte order, transform it
+	knot_wire_write_u32((uint8_t *)(rdata->items[2].raw_data + 1),
+	                    serial);
+}
+
+/*---------------------------------------------------------------------------*/
 
 uint32_t knot_rdata_soa_refresh(const knot_rdata_t *rdata)
 {
@@ -816,3 +828,43 @@ const uint8_t *knot_rdata_nsec3_salt(const knot_rdata_t *rdata)
 	
 	return ((uint8_t *)(rdata->items[3].raw_data + 1)) + 1;
 }
+
+/*----------------------------------------------------------------------------*/
+
+uint8_t knot_rdata_ds_digest_type(const knot_rdata_t *rdata)
+{
+	if (rdata->count < 3) {
+		return 0;
+	}
+
+	return *((uint8_t *)(rdata->items[2].raw_data + 1));
+}
+
+/*----------------------------------------------------------------------------*/
+
+uint16_t knot_rdata_ds_digest_len(const knot_rdata_t *rdata)
+{
+	if (rdata->count < 4) {
+		return 0;
+	}
+
+	return *(rdata->items[3].raw_data);
+}
+
+/*----------------------------------------------------------------------------*/
+
+int knot_rdata_ds_check(const knot_rdata_t *rdata)
+{
+	// Check if the legth of the digest corresponds to the proper size of
+	// the digest according to the given algorithm
+	uint16_t len = knot_rdata_ds_digest_len(rdata);
+	uint8_t type = knot_rdata_ds_digest_type(rdata);
+
+	if (type == 0 || len == 0) {
+		return KNOT_EINVAL;
+	} else if (len != knot_ds_digest_length(type)) {
+		return KNOT_EDSDIGESTLEN;
+	} else {
+		return KNOT_EOK;
+	}
+}
diff --git a/src/libknot/rdata.h b/src/libknot/rdata.h
index 57517bd..eb7bd55 100644
--- a/src/libknot/rdata.h
+++ b/src/libknot/rdata.h
@@ -329,6 +329,7 @@ const knot_dname_t *knot_rdata_get_name(const knot_rdata_t *rdata,
                                             uint16_t type);
 
 int64_t knot_rdata_soa_serial(const knot_rdata_t *rdata);
+void knot_rdata_soa_serial_set(knot_rdata_t *rdata, uint32_t serial);
 
 uint32_t knot_rdata_soa_refresh(const knot_rdata_t *rdata);
 uint32_t knot_rdata_soa_retry(const knot_rdata_t *rdata);
@@ -342,6 +343,10 @@ uint16_t knot_rdata_nsec3_iterations(const knot_rdata_t *rdata);
 uint8_t knot_rdata_nsec3_salt_length(const knot_rdata_t *rdata);
 const uint8_t *knot_rdata_nsec3_salt(const knot_rdata_t *rdata);
 
+uint8_t knot_rdata_ds_digest_type(const knot_rdata_t *rdata);
+uint16_t knot_rdata_ds_digest_len(const knot_rdata_t *rdata);
+int knot_rdata_ds_check(const knot_rdata_t *rdata);
+
 #endif /* _KNOT_RDATA_H */
 
 /*! @} */
diff --git a/src/libknot/rrset.c b/src/libknot/rrset.c
index d8b10ce..84d5075 100644
--- a/src/libknot/rrset.c
+++ b/src/libknot/rrset.c
@@ -215,7 +215,7 @@ int knot_rrset_add_rrsigs(knot_rrset_t *rrset, knot_rrset_t *rrsigs,
 		if (dupl == KNOT_RRSET_DUPL_MERGE) {
 			rc = knot_rrset_merge_no_dupl((void **)&rrset->rrsigs,
 			                              (void **)&rrsigs);
-			if (rc != KNOT_EOK) {
+			if (rc < 0) {
 				return rc;
 			} else {
 				return 1;
@@ -280,6 +280,15 @@ void knot_rrset_set_ttl(knot_rrset_t *rrset, uint32_t ttl)
 
 /*----------------------------------------------------------------------------*/
 
+void knot_rrset_set_class(knot_rrset_t *rrset, uint16_t rclass)
+{
+	if (rrset) {
+		rrset->rclass = rclass;
+	}
+}
+
+/*----------------------------------------------------------------------------*/
+
 uint16_t knot_rrset_type(const knot_rrset_t *rrset)
 {
 	return rrset->type;
@@ -604,7 +613,7 @@ int knot_rrset_to_wire(const knot_rrset_t *rrset, uint8_t *wire, size_t *size,
 
 /*----------------------------------------------------------------------------*/
 
-int knot_rrset_compare(const knot_rrset_t *r1,
+int knot_rrset_match(const knot_rrset_t *r1,
                        const knot_rrset_t *r2,
                        knot_rrset_compare_type_t cmp)
 {
@@ -838,6 +847,7 @@ dbg_rrset_exec_detail(
 	}
 
 	knot_rdata_t *walk2 = rrset2->rdata;
+	int deleted = 0;
 
 	// no RDATA in RRSet 1
 	if (rrset1->rdata == NULL && rrset2->rdata != NULL) {
@@ -934,6 +944,7 @@ dbg_rrset_exec_detail(
 			knot_rdata_deep_free(&tmp, rrset1->type, 1);
 			assert(tmp == NULL);
 			/* Maybe caller should be warned about this. */
+			++deleted;
 		}
 	}
 	
@@ -954,5 +965,5 @@ dbg_rrset_exec_detail(
 	 */
 	rrset2->rdata = NULL;
 
-	return KNOT_EOK;
+	return deleted;
 }
diff --git a/src/libknot/rrset.h b/src/libknot/rrset.h
index b5b62db..077b067 100644
--- a/src/libknot/rrset.h
+++ b/src/libknot/rrset.h
@@ -163,6 +163,8 @@ void knot_rrset_set_owner(knot_rrset_t *rrset, knot_dname_t* owner);
 
 void knot_rrset_set_ttl(knot_rrset_t *rrset, uint32_t ttl);
 
+void knot_rrset_set_class(knot_rrset_t *rrset, uint16_t rclass);
+
 /*!
  * \brief Returns the TYPE of the RRSet.
  *
@@ -259,7 +261,7 @@ int knot_rrset_to_wire(const knot_rrset_t *rrset, uint8_t *wire, size_t *size,
  * \retval <> 0 If RRSets are equal.
  * \retval 0 if RRSets are not equal.
  */
-int knot_rrset_compare(const knot_rrset_t *r1,
+int knot_rrset_match(const knot_rrset_t *r1,
                          const knot_rrset_t *r2,
                          knot_rrset_compare_type_t cmp);
 
@@ -344,6 +346,8 @@ int knot_rrset_merge(void **r1, void **r2);
  * \retval KNOT_EOK
  * \retval KNOT_EINVAL if the RRSets could not be merged, because their
  *         Owner, Type, Class or TTL does not match.
+ * \retval >0 if some RDATA have been removed because they were duplicate. The
+ *         return value indicates number of such RDATA.
  */
 int knot_rrset_merge_no_dupl(void **r1, void **r2);
 
diff --git a/src/libknot/tsig-op.c b/src/libknot/tsig-op.c
index cb280ab..55316a9 100644
--- a/src/libknot/tsig-op.c
+++ b/src/libknot/tsig-op.c
@@ -108,20 +108,16 @@ static int knot_tsig_compute_digest(const uint8_t *wire, size_t wire_len,
 	char decoded_key[B64BUFSIZE];
 	memset(decoded_key, 0, sizeof(decoded_key));
 	
-	size_t decoded_key_size = B64BUFSIZE;
-	int ret = base64_decode(key->secret, strlen(key->secret),
-	                        decoded_key,
-	                        &decoded_key_size);
-	if (ret != 1) {
-		dbg_tsig("TSIG: New decode function failed! (%d)\n", ret);
-		return KNOT_ERROR;
-	}
-	
-	if (decoded_key_size < 0) {
+	int32_t ret = base64_decode((uint8_t *)key->secret, strlen(key->secret),
+	                            (uint8_t *)decoded_key, B64BUFSIZE);
+
+	if (ret < 0) {
 		dbg_tsig("TSIG: Could not decode Base64\n");
 		return KNOT_ERROR;
 	}
 	
+	size_t decoded_key_size = ret;
+
 	dbg_tsig_detail("TSIG: decoded key size: %d\n", decoded_key_size);
 	dbg_tsig_detail("TSIG: decoded key:\n");
 	dbg_tsig_hex_detail(decoded_key, decoded_key_size);
@@ -221,14 +217,14 @@ static int knot_tsig_write_tsig_variables(uint8_t *wire,
 
 	/* Copy class. */
 	knot_wire_write_u16(wire + offset, knot_rrset_class(tsig_rr));
-	dbg_tsig_verb("TSIG: write variables: written CLASS: %u - ",
+	dbg_tsig_verb("TSIG: write variables: written CLASS: %u - \n",
 	               knot_rrset_class(tsig_rr));
 	dbg_tsig_hex_detail(wire + offset, sizeof(uint16_t));
 	offset += sizeof(uint16_t);
 
 	/* Copy TTL - always 0. */
 	knot_wire_write_u32(wire + offset, knot_rrset_ttl(tsig_rr));
-	dbg_tsig_verb("TSIG: write variables: written TTL: %u - ",
+	dbg_tsig_verb("TSIG: write variables: written TTL: %u - \n",
 	              knot_rrset_ttl(tsig_rr));
 	dbg_tsig_hex_detail(wire + offset, sizeof(uint32_t));
 	offset += sizeof(uint32_t);
@@ -816,6 +812,9 @@ static int knot_tsig_check_digest(const knot_rrset_t *tsig_rr,
 
 	memset(wire_to_sign, 0, sizeof(uint8_t) * size);
 	memcpy(wire_to_sign, wire, size);
+	
+	/* Restore message id. */
+	knot_wire_set_id(wire_to_sign, tsig_rdata_orig_id(tsig_rr));
 
 	/* Decrease arcount. */
 	knot_wire_set_arcount(wire_to_sign,
@@ -864,10 +863,10 @@ static int knot_tsig_check_digest(const knot_rrset_t *tsig_rr,
 		return KNOT_TSIG_EBADSIG;
 	}
 
-	dbg_tsig_verb("TSIG: calc digest : ");
+	dbg_tsig_verb("TSIG: calc digest :\n");
 	dbg_tsig_hex_verb(digest_tmp, digest_tmp_len);
 
-	dbg_tsig_verb("TSIG: given digest: ");
+	dbg_tsig_verb("TSIG: given digest:\n");
 	dbg_tsig_hex_verb(tsig_mac, mac_length);
 
 	if (strncasecmp((char *)(tsig_mac), (char *)digest_tmp,
diff --git a/src/libknot/updates/changesets.c b/src/libknot/updates/changesets.c
index ab83b07..5405726 100644
--- a/src/libknot/updates/changesets.c
+++ b/src/libknot/updates/changesets.c
@@ -66,7 +66,7 @@ static int knot_changeset_check_count(knot_rrset_t ***rrsets, size_t count,
 static int knot_changeset_rrsets_match(const knot_rrset_t *rrset1,
                                          const knot_rrset_t *rrset2)
 {
-	return knot_rrset_compare(rrset1, rrset2, KNOT_RRSET_COMPARE_HEADER)
+	return knot_rrset_match(rrset1, rrset2, KNOT_RRSET_COMPARE_HEADER)
 	       && (knot_rrset_type(rrset1) != KNOT_RRTYPE_RRSIG
 	           || knot_rdata_rrsig_type_covered(
 	                    knot_rrset_rdata(rrset1))
@@ -76,7 +76,8 @@ static int knot_changeset_rrsets_match(const knot_rrset_t *rrset1,
 
 /*----------------------------------------------------------------------------*/
 
-int knot_changeset_allocate(knot_changesets_t **changesets)
+int knot_changeset_allocate(knot_changesets_t **changesets,
+                            uint32_t flags)
 {
 	// create new changesets
 	*changesets = (knot_changesets_t *)(malloc(sizeof(knot_changesets_t)));
@@ -85,8 +86,15 @@ int knot_changeset_allocate(knot_changesets_t **changesets)
 	}
 
 	memset(*changesets, 0, sizeof(knot_changesets_t));
+	(*changesets)->flags = flags;
 
-	return knot_changesets_check_size(*changesets);
+	if (knot_changesets_check_size(*changesets) != KNOT_EOK) {
+		free(*changesets);
+		*changesets = NULL;
+		return KNOT_ENOMEM;
+	}
+	
+	return KNOT_EOK;
 }
 
 /*----------------------------------------------------------------------------*/
@@ -138,19 +146,19 @@ int knot_changeset_add_rr(knot_rrset_t ***rrsets, size_t *count,
 
 int knot_changeset_add_new_rr(knot_changeset_t *changeset,
                                knot_rrset_t *rrset,
-                               xfrin_changeset_part_t part)
+                               knot_changeset_part_t part)
 {
 	knot_rrset_t ***rrsets = NULL;
 	size_t *count = NULL;
 	size_t *allocated = NULL;
 
 	switch (part) {
-	case XFRIN_CHANGESET_ADD:
+	case KNOT_CHANGESET_ADD:
 		rrsets = &changeset->add;
 		count = &changeset->add_count;
 		allocated = &changeset->add_allocated;
 		break;
-	case XFRIN_CHANGESET_REMOVE:
+	case KNOT_CHANGESET_REMOVE:
 		rrsets = &changeset->remove;
 		count = &changeset->remove_count;
 		allocated = &changeset->remove_allocated;
@@ -173,6 +181,29 @@ int knot_changeset_add_new_rr(knot_changeset_t *changeset,
 
 /*----------------------------------------------------------------------------*/
 
+knot_rrset_t *knot_changeset_remove_rr(knot_rrset_t **rrsets, size_t *count,
+                                       int pos)
+{
+	if (pos >= *count || *count == 0) {
+		return NULL;
+	}
+
+	knot_rrset_t *removed = rrsets[pos];
+
+	// shift all RRSets from pos+1 one cell to the left
+	for (int i = pos; i < *count - 1; ++i) {
+		rrsets[i] = rrsets[i + 1];
+	}
+
+	// just to be sure, set the last previously occupied position to NULL
+	rrsets[*count - 1] = NULL;
+	*count -= 1;
+
+	return removed;
+}
+
+/*----------------------------------------------------------------------------*/
+
 void knot_changeset_store_soa(knot_rrset_t **chg_soa,
                                uint32_t *chg_serial, knot_rrset_t *soa)
 {
@@ -183,14 +214,14 @@ void knot_changeset_store_soa(knot_rrset_t **chg_soa,
 /*----------------------------------------------------------------------------*/
 
 int knot_changeset_add_soa(knot_changeset_t *changeset, knot_rrset_t *soa,
-                            xfrin_changeset_part_t part)
+                            knot_changeset_part_t part)
 {
 	switch (part) {
-	case XFRIN_CHANGESET_ADD:
+	case KNOT_CHANGESET_ADD:
 		knot_changeset_store_soa(&changeset->soa_to,
 		                          &changeset->serial_to, soa);
 		break;
-	case XFRIN_CHANGESET_REMOVE:
+	case KNOT_CHANGESET_REMOVE:
 		knot_changeset_store_soa(&changeset->soa_from,
 		                          &changeset->serial_from, soa);
 		break;
@@ -212,7 +243,8 @@ int knot_changesets_check_size(knot_changesets_t *changesets)
 	}
 
 	/* How many steps is needed to content count? */
-	size_t extra = (changesets->count - changesets->allocated) % KNOT_CHANGESET_STEP;
+	size_t extra = (changesets->count - changesets->allocated)
+	                % KNOT_CHANGESET_STEP;
 	extra = (extra + 1) * KNOT_CHANGESET_STEP;
 
 	/* Allocate new memory block. */
@@ -223,10 +255,15 @@ int knot_changesets_check_size(knot_changesets_t *changesets)
 		return KNOT_ENOMEM;
 	}
 
-	/* Clear old memory block and copy old data. */
+	/* Clear new memory block and copy old data. */
 	memset(sets, 0, new_count * item_len);
 	memcpy(sets, changesets->sets, changesets->allocated * item_len);
 
+	/* Set type to all newly allocated changesets. */
+	for (int i = changesets->allocated; i < new_count; ++i) {
+		sets[i].flags = changesets->flags;
+	}
+
 	/* Replace old changesets. */
 	free(changesets->sets);
 	changesets->sets = sets;
@@ -237,6 +274,32 @@ int knot_changesets_check_size(knot_changesets_t *changesets)
 
 /*----------------------------------------------------------------------------*/
 
+void knot_changeset_set_flags(knot_changeset_t *changeset,
+                             uint32_t flags)
+{
+	changeset->flags = flags;
+}
+
+/*----------------------------------------------------------------------------*/
+
+uint32_t knot_changeset_flags(knot_changeset_t *changeset)
+{
+	return changeset->flags;
+}
+
+/*----------------------------------------------------------------------------*/
+
+int knot_changeset_is_empty(const knot_changeset_t *changeset)
+{
+	if (changeset == NULL) {
+		return 0;
+	}
+
+	return (changeset->add_count == 0 && changeset->remove_count == 0);
+}
+
+/*----------------------------------------------------------------------------*/
+
 void knot_free_changeset(knot_changeset_t **changeset)
 {
 	assert((*changeset)->add_allocated >= (*changeset)->add_count);
@@ -287,3 +350,274 @@ void knot_free_changesets(knot_changesets_t **changesets)
 	free(*changesets);
 	*changesets = NULL;
 }
+
+/*----------------------------------------------------------------------------*/
+/* knot_changes_t manipulation                                                */
+/*----------------------------------------------------------------------------*/
+
+int knot_changes_rrsets_reserve(knot_rrset_t ***rrsets,
+                              int *count, int *allocated, int to_add)
+{
+	if (rrsets == NULL || count == NULL || allocated == NULL) {
+		return KNOT_EINVAL;
+	}
+	
+	if (*count + to_add <= *allocated) {
+		return KNOT_EOK;
+	}
+
+	int new_count = (*allocated == 0) ? 2 : *allocated * 2;
+	while (new_count < *count + to_add) {
+		new_count *= 2;
+	}
+
+	/* Allocate new memory block. */
+	knot_rrset_t **rrsets_new = malloc(new_count * sizeof(knot_rrset_t *));
+	if (rrsets_new == NULL) {
+		return KNOT_ENOMEM;
+	}
+
+	/* Initialize new memory and copy old data. */
+	memset(rrsets_new, 0, new_count * sizeof(knot_rrset_t *));
+	memcpy(rrsets_new, *rrsets, (*allocated) * sizeof(knot_rrset_t *));
+
+	/* Free old nodes and switch pointers. */
+	free(*rrsets);
+	*rrsets = rrsets_new;
+	*allocated = new_count;
+
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
+int knot_changes_nodes_reserve(knot_node_t ***nodes,
+                             int *count, int *allocated)
+{
+	if (nodes == NULL || count == NULL || allocated == NULL) {
+		return KNOT_EINVAL;
+	}
+	
+	if (*count + 2 <= *allocated) {
+		return KNOT_EOK;
+	}
+
+	int new_count = (*allocated == 0) ? 2 : *allocated * 2;
+
+	/* Allocate new memory block. */
+	const size_t node_len = sizeof(knot_node_t *);
+	knot_node_t **nodes_new = malloc(new_count * node_len);
+	if (nodes_new == NULL) {
+		return KNOT_ENOMEM;
+	}
+
+	/* Clear memory block and copy old data. */
+	memset(nodes_new, 0, new_count * node_len);
+	memcpy(nodes_new, *nodes, (*allocated) * node_len);
+
+	/* Free old nodes and switch pointers. */
+	free(*nodes);
+	*nodes = nodes_new;
+	*allocated = new_count;
+
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
+int knot_changes_rdata_reserve(knot_rdata_t ***rdatas, uint16_t **types,
+                             int count, int *allocated, int to_add)
+{
+	if (rdatas == NULL || types == NULL || allocated == NULL) {
+		return KNOT_EINVAL;
+	}
+	
+	if (count + to_add <= *allocated) {
+		return KNOT_EOK;
+	}
+
+	int new_count = (*allocated == 0) ? 2 : *allocated * 2;
+	while (new_count < count + to_add) {
+		new_count *= 2;
+	}
+
+	/* Allocate new memory block. */
+	knot_rdata_t **rdatas_new = malloc(new_count * sizeof(knot_rdata_t *));
+	if (rdatas_new == NULL) {
+		return KNOT_ENOMEM;
+	}
+
+	uint16_t *types_new = malloc(new_count * sizeof(uint));
+	if (types_new == NULL) {
+		free(rdatas_new);
+		return KNOT_ENOMEM;
+	}
+
+	/* Initialize new memory and copy old data. */
+	memset(rdatas_new, 0, new_count * sizeof(knot_rdata_t *));
+	memcpy(rdatas_new, *rdatas, (*allocated) * sizeof(knot_rdata_t *));
+
+	memset(types_new, 0, new_count * sizeof(uint));
+	memcpy(types_new, *types, (*allocated) * sizeof(uint));
+
+	/* Free old rdatas and switch pointers. */
+	free(*rdatas);
+	free(*types);
+	*rdatas = rdatas_new;
+	*types = types_new;
+	*allocated = new_count;
+
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
+void knot_changes_add_rdata(knot_rdata_t **rdatas, uint16_t *types,
+                            int *count, knot_rdata_t *rdata, uint16_t type)
+{
+	if (rdatas == NULL || types == NULL || count == NULL || rdata == NULL) {
+		return;
+	}
+
+	// Add all RDATAs from the chain!!
+
+	knot_rdata_t *r = rdata;
+	do {
+//		dbg_xfrin_detail("Adding RDATA to RDATA list: %p\n", r);
+		rdatas[*count] = r;
+		types[*count] = type;
+		++*count;
+
+		r = r->next;
+	} while (r != NULL && r != rdata);
+}
+
+/*----------------------------------------------------------------------------*/
+
+int knot_changes_add_old_rrsets(knot_rrset_t **rrsets, int count,
+                                knot_changes_t *changes, int add_rdata)
+{
+	if (rrsets == NULL || changes == NULL) {
+		return KNOT_EINVAL;
+	}
+
+	if (count == 0) {
+		return KNOT_EOK;
+	}
+
+	/* Reserve twice the space, to have enough space for RRSIGs if
+	 * there are some.
+	 */
+	int ret = knot_changes_rrsets_reserve(&changes->old_rrsets,
+	                                      &changes->old_rrsets_count,
+	                                      &changes->old_rrsets_allocated,
+	                                      2 * count);
+	if (ret != KNOT_EOK) {
+//		dbg_xfrin("Failed to reserve changes rrsets.\n");
+		return ret;
+	}
+
+	/* Mark RRsets and RDATA for removal. */
+	for (unsigned i = 0; i < count; ++i) {
+		if (rrsets[i] == NULL) {
+			continue;
+		}
+		
+		knot_rrset_t *rrsigs = knot_rrset_get_rrsigs(rrsets[i]);
+		
+		if (add_rdata) {
+			
+			/* RDATA count in the RRSet. */
+			int rdata_count = knot_rrset_rdata_rr_count(rrsets[i]);
+			
+			if (rrsigs != NULL) {
+				/* Increment the RDATA count by the count of 
+				 * RRSIGs. */
+				rdata_count += knot_rrset_rdata_rr_count(
+				                        rrsigs);
+			}
+	
+			/* Remove old RDATA. */
+			
+			ret = knot_changes_rdata_reserve(&changes->old_rdata,
+			                          &changes->old_rdata_types,
+			                          changes->old_rdata_count,
+			                          &changes->old_rdata_allocated,
+			                          rdata_count);
+			if (ret != KNOT_EOK) {
+//				dbg_xfrin("Failed to reserve changes rdata.\n");
+				return ret;
+			}
+
+			knot_changes_add_rdata(changes->old_rdata,
+			                       changes->old_rdata_types,
+			                       &changes->old_rdata_count,
+			                       knot_rrset_get_rdata(rrsets[i]),
+			                       knot_rrset_type(rrsets[i]));
+			
+			knot_changes_add_rdata(changes->old_rdata,
+			                       changes->old_rdata_types,
+			                       &changes->old_rdata_count,
+			                       knot_rrset_get_rdata(rrsigs),
+			                       KNOT_RRTYPE_RRSIG);
+		}
+		
+		/* Disconnect RRsigs from rrset. */
+		knot_rrset_set_rrsigs(rrsets[i], NULL);
+		changes->old_rrsets[changes->old_rrsets_count++] = rrsets[i];
+		changes->old_rrsets[changes->old_rrsets_count++] = rrsigs;
+	}
+
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
+int knot_changes_add_new_rrsets(knot_rrset_t **rrsets, int count,
+                                knot_changes_t *changes, int add_rdata)
+{
+	if (rrsets == NULL || changes == NULL) {
+		return KNOT_EINVAL;
+	}
+
+	if (count == 0) {
+		return KNOT_EOK;
+	}
+
+	int ret = knot_changes_rrsets_reserve(&changes->new_rrsets,
+	                                      &changes->new_rrsets_count,
+	                                      &changes->new_rrsets_allocated,
+	                                      count);
+	if (ret != KNOT_EOK) {
+		return ret;
+	}
+
+	/* Mark RRsets and RDATA for removal. */
+	for (unsigned i = 0; i < count; ++i) {
+		if (rrsets[i] == NULL) {
+			continue;
+		}
+		
+		if (add_rdata) {
+			int rdata_count = knot_rrset_rdata_rr_count(rrsets[i]);
+			ret = knot_changes_rdata_reserve(&changes->new_rdata,
+			                          &changes->new_rdata_types,
+			                          changes->new_rdata_count,
+			                          &changes->new_rdata_allocated,
+			                          rdata_count);
+			if (ret != KNOT_EOK) {
+				return ret;
+			}
+			
+			knot_changes_add_rdata(changes->new_rdata,
+			                       changes->new_rdata_types,
+			                       &changes->new_rdata_count,
+			                       knot_rrset_get_rdata(rrsets[i]),
+			                       knot_rrset_type(rrsets[i]));
+		}	
+		
+		changes->new_rrsets[changes->new_rrsets_count++] = rrsets[i];
+	}
+
+	return KNOT_EOK;
+}
diff --git a/src/libknot/updates/changesets.h b/src/libknot/updates/changesets.h
index 642b155..4585abc 100644
--- a/src/libknot/updates/changesets.h
+++ b/src/libknot/updates/changesets.h
@@ -30,6 +30,14 @@
 #include "rrset.h"
 #include "zone/node.h"
 
+/*----------------------------------------------------------------------------*/
+
+/*! \brief Changeset flags, stored as first 4 bytes in serialized changeset. */
+typedef enum {
+	KNOT_CHANGESET_TYPE_IXFR = 1 << 0,
+	KNOT_CHANGESET_TYPE_DDNS = 1 << 1
+} knot_changeset_flag_t;
+
 /*! \todo Changeset must be serializable/deserializable, so
  *        all data and pointers have to be changeset-exclusive,
  *        or more advanced structure serialization scheme has to be
@@ -53,6 +61,8 @@ typedef struct {
 	size_t allocated;
 	uint32_t serial_from;
 	uint32_t serial_to;
+
+	uint32_t flags;  /*!< DDNS / IXFR */
 } knot_changeset_t;
 
 /*----------------------------------------------------------------------------*/
@@ -69,7 +79,7 @@ typedef struct {
 	 * Deleted after successful update.
 	 */
 	knot_rdata_t **old_rdata;
-	unsigned *old_rdata_types;
+	uint16_t *old_rdata_types;
 	int old_rdata_count;
 	int old_rdata_allocated;
 
@@ -86,7 +96,7 @@ typedef struct {
 	 * Deleted after failed update.
 	 */
 	knot_rdata_t **new_rdata;
-	unsigned *new_rdata_types;
+	uint16_t *new_rdata_types;
 	int new_rdata_count;
 	int new_rdata_allocated;
 
@@ -109,19 +119,21 @@ typedef struct {
 	size_t count;
 	size_t allocated;
 	knot_rrset_t *first_soa;
+	uint32_t flags;
 	knot_changes_t *changes;
 } knot_changesets_t;
 
 /*----------------------------------------------------------------------------*/
 
 typedef enum {
-	XFRIN_CHANGESET_ADD,
-	XFRIN_CHANGESET_REMOVE
-} xfrin_changeset_part_t;
+	KNOT_CHANGESET_ADD,
+	KNOT_CHANGESET_REMOVE
+} knot_changeset_part_t;
 
 /*----------------------------------------------------------------------------*/
 
-int knot_changeset_allocate(knot_changesets_t **changesets);
+int knot_changeset_allocate(knot_changesets_t **changesets,
+                            uint32_t flags);
 
 int knot_changeset_add_rrset(knot_rrset_t ***rrsets,
                              size_t *count, size_t *allocated,
@@ -132,20 +144,51 @@ int knot_changeset_add_rr(knot_rrset_t ***rrsets, size_t *count,
 
 int knot_changeset_add_new_rr(knot_changeset_t *changeset,
                               knot_rrset_t *rrset,
-                              xfrin_changeset_part_t part);
+                              knot_changeset_part_t part);
+
+knot_rrset_t *knot_changeset_remove_rr(knot_rrset_t **rrsets, size_t *count,
+                                       int pos);
 
 void knot_changeset_store_soa(knot_rrset_t **chg_soa,
                               uint32_t *chg_serial, knot_rrset_t *soa);
 
 int knot_changeset_add_soa(knot_changeset_t *changeset, knot_rrset_t *soa,
-                           xfrin_changeset_part_t part);
+                           knot_changeset_part_t part);
 
 int knot_changesets_check_size(knot_changesets_t *changesets);
 
+void knot_changeset_set_flags(knot_changeset_t *changeset,
+                             uint32_t flags);
+
+uint32_t knot_changeset_flags(knot_changeset_t *changeset);
+
+int knot_changeset_is_empty(const knot_changeset_t *changeset);
+
 void knot_free_changeset(knot_changeset_t **changeset);
 
 void knot_free_changesets(knot_changesets_t **changesets);
 
+int knot_changes_rrsets_reserve(knot_rrset_t ***rrsets,
+                                int *count, int *allocated, int to_add);
+
+int knot_changes_nodes_reserve(knot_node_t ***nodes,
+                               int *count, int *allocated);
+
+int knot_changes_rdata_reserve(knot_rdata_t ***rdatas, uint16_t **types,
+                               int count, int *allocated, int to_add);
+
+void knot_changes_add_rdata(knot_rdata_t **rdatas, uint16_t *types,
+                            int *count, knot_rdata_t *rdata, uint16_t type);
+
+/*!
+ * \note Also processes RRSIGs. May be switched by a parameter later, if needed.
+ */
+int knot_changes_add_old_rrsets(knot_rrset_t **rrsets, int count,
+                                knot_changes_t *changes, int add_rdata);
+
+int knot_changes_add_new_rrsets(knot_rrset_t **rrsets, int count,
+                                knot_changes_t *changes, int add_rdata);
+
 #endif /* _KNOT_CHANGESETS_H_ */
 
 /*! @} */
diff --git a/src/libknot/updates/ddns.c b/src/libknot/updates/ddns.c
index 72a1be9..90a578f 100644
--- a/src/libknot/updates/ddns.c
+++ b/src/libknot/updates/ddns.c
@@ -21,26 +21,24 @@
 #include "util/debug.h"
 #include "packet/packet.h"
 #include "consts.h"
+#include "common/mempattern.h"
+#include "nameserver/name-server.h"  // ns_serial_compare() - TODO: extract
+#include "updates/xfr-in.h"
 
 /*----------------------------------------------------------------------------*/
 // Copied from XFR - maybe extract somewhere else
 static int knot_ddns_prereq_check_rrsets(knot_rrset_t ***rrsets,
                                          size_t *count, size_t *allocated)
 {
-	int new_count = 0;
-	if (*count == *allocated) {
-		new_count = *allocated * 2;
-	}
-
-	knot_rrset_t **rrsets_new =
-		(knot_rrset_t **)calloc(new_count, sizeof(knot_rrset_t *));
-	if (rrsets_new == NULL) {
+	/* This is really confusing, it's ptr -> array of "knot_rrset_t*" */
+	char *arr = (char*)*rrsets;
+	int ret = 0;
+	ret = mreserve(&arr, sizeof(knot_rrset_t*), *count + 1, 0, allocated);
+	if (ret < 0) {
 		return KNOT_ENOMEM;
 	}
-
-	memcpy(rrsets_new, *rrsets, (*count) * sizeof(knot_rrset_t *));
-	*rrsets = rrsets_new;
-	*allocated = new_count;
+	
+	*rrsets = (knot_rrset_t**)arr;
 
 	return KNOT_EOK;
 }
@@ -50,20 +48,15 @@ static int knot_ddns_prereq_check_rrsets(knot_rrset_t ***rrsets,
 static int knot_ddns_prereq_check_dnames(knot_dname_t ***dnames,
                                          size_t *count, size_t *allocated)
 {
-	int new_count = 0;
-	if (*count == *allocated) {
-		new_count = *allocated * 2;
-	}
-
-	knot_dname_t **dnames_new =
-		(knot_dname_t **)calloc(new_count, sizeof(knot_dname_t *));
-	if (dnames_new == NULL) {
+	/* This is really confusing, it's ptr -> array of "knot_dname_t*" */
+	char *arr = (char*)*dnames;
+	int ret = 0;
+	ret = mreserve(&arr, sizeof(knot_dname_t*), *count + 1, 0, allocated);
+	if (ret < 0) {
 		return KNOT_ENOMEM;
 	}
-
-	memcpy(dnames_new, *dnames, (*count) * sizeof(knot_dname_t *));
-	*dnames = dnames_new;
-	*allocated = new_count;
+	
+	*dnames = (knot_dname_t**)arr;
 
 	return KNOT_EOK;
 }
@@ -77,8 +70,8 @@ static int knot_ddns_add_prereq_rrset(const knot_rrset_t *rrset,
 	// check if such RRSet is not already there and merge if needed
 	int ret;
 	for (int i = 0; i < *count; ++i) {
-		if (knot_rrset_compare(rrset, (*rrsets)[i],
-		                       KNOT_RRSET_COMPARE_HEADER) == 0) {
+		if (knot_rrset_match(rrset, (*rrsets)[i],
+		                       KNOT_RRSET_COMPARE_HEADER) == 1) {
 			ret = knot_rrset_merge((void **)&((*rrsets)[i]),
 			                       (void **)&rrset);
 			if (ret != KNOT_EOK) {
@@ -188,39 +181,119 @@ static int knot_ddns_add_prereq(knot_ddns_prereq_t *prereqs,
 
 /*----------------------------------------------------------------------------*/
 
+static int knot_ddns_check_remove_rr(knot_changeset_t *changeset,
+                                     const knot_rrset_t *rr)
+{
+	dbg_ddns_verb("Removing possible redundant RRs from changeset.\n");
+	for (int i = 0; i < changeset->add_count; ++i) {
+		// Removing RR(s) from this owner
+		if (knot_dname_compare(knot_rrset_owner(rr),
+		                       knot_rrset_owner(changeset->add[i])) == 0) {
+			// Removing one or all RRSets
+			if (knot_rrset_class(rr) == KNOT_CLASS_ANY) {
+				dbg_ddns_detail("Removing one or all "
+				                "RRSets\n");
+				if (knot_rrset_type(rr)
+				    == knot_rrset_type(changeset->add[i])
+				    || knot_rrset_type(rr) == KNOT_RRTYPE_ANY) {
+					knot_rrset_t *remove =
+						knot_changeset_remove_rr(
+						    changeset->add,
+						    &changeset->add_count, i);
+					dbg_ddns_detail("Removed RRSet from "
+					                "chgset:\n");
+					knot_rrset_dump(remove, 0);
+					knot_rrset_deep_free(&remove, 1, 1, 1);
+				}
+			} else if (knot_rrset_type(rr)
+			           == knot_rrset_type(changeset->add[i])){
+				/* All other classes are checked in
+				 * knot_ddns_check_update().
+				 */
+				assert(knot_rrset_class(rr) == KNOT_CLASS_NONE);
+
+				// Removing specific RR from a RRSet
+				knot_rdata_t *rdata = knot_rrset_remove_rdata(
+				                        changeset->add[i],
+				                        knot_rrset_rdata(rr));
+
+				dbg_ddns_detail("Removed RR from chgset: \n");
+				knot_rdata_dump(rdata, knot_rrset_type(rr), 0);
+
+				knot_rdata_deep_free(&rdata,
+				         knot_rrset_type(changeset->add[i]), 1);
+				// if the RRSet is empty, remove from changeset
+				if (knot_rrset_rdata_rr_count(changeset->add[i])
+				    == 0) {
+					knot_rrset_t *remove =
+						knot_changeset_remove_rr(
+						    changeset->add,
+						    &changeset->add_count, i);
+					dbg_ddns_detail("RRSet empty, removing."
+					                "\n");
+					knot_rrset_deep_free(&remove, 1, 1, 1);
+				}
+			}
+		}
+	}
+
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
 static int knot_ddns_add_update(knot_changeset_t *changeset,
-                         const knot_rrset_t *rrset, uint16_t qclass)
+                                const knot_rrset_t *rrset, uint16_t qclass,
+                                knot_rrset_t **rrset_copy)
 {
 	assert(changeset != NULL);
 	assert(rrset != NULL);
+	assert(rrset_copy != NULL);
 
 	int ret;
 
 	// create a copy of the RRSet
-	/*! \todo If the packet was not parsed all at once, we could save this
+	/*! \todo ref #937 If the packet was not parsed all at once, we could save this
 	 *        copy.
 	 */
-	knot_rrset_t *rrset_copy;
-	ret = knot_rrset_deep_copy(rrset, &rrset_copy, 0);
+	*rrset_copy = NULL;
+	ret = knot_rrset_deep_copy(rrset, rrset_copy, 0);
 	if (ret != KNOT_EOK) {
 		return ret;
 	}
 
-	/*! \todo What about the SOAs? */
-
 	if (knot_rrset_class(rrset) == qclass) {
 		// this RRSet should be added to the zone
+		dbg_ddns_detail(" * adding RR %p\n", *rrset_copy);
 		ret = knot_changeset_add_rr(&changeset->add,
 		                            &changeset->add_count,
 		                            &changeset->add_allocated,
-		                            rrset_copy);
+		                            *rrset_copy);
 	} else {
 		// this RRSet marks removal of something from zone
-		// what should be removed is distinguished when applying
+
+		/* To imitate in-order processing of UPDATE RRs, we must check
+		 * If this REMOVE RR does not affect any of the previous
+		 * ADD RRs in this update. If yes, they must be removed from
+		 * the changeset.
+		 *
+		 * See https://git.nic.cz/redmine/issues/937#note-14 and below.
+		 */
+
+		// TODO: finish, disabled for now
+
+		dbg_ddns_detail(" * removing RR %p\n", *rrset_copy);
+
+		ret = knot_ddns_check_remove_rr(changeset, *rrset_copy);
+		if (ret != KNOT_EOK) {
+			knot_rrset_deep_free(rrset_copy, 1, 1, 1);
+			return ret;
+		}
+
 		ret = knot_changeset_add_rr(&changeset->remove,
 		                            &changeset->remove_count,
 		                            &changeset->remove_allocated,
-		                            rrset_copy);
+		                            *rrset_copy);
 	}
 
 	return ret;
@@ -229,7 +302,7 @@ static int knot_ddns_add_update(knot_changeset_t *changeset,
 /*----------------------------------------------------------------------------*/
 
 static int knot_ddns_check_exist(const knot_zone_contents_t *zone,
-                                 const knot_rrset_t *rrset, uint8_t *rcode)
+                                 const knot_rrset_t *rrset, knot_rcode_t *rcode)
 {
 	assert(zone != NULL);
 	assert(rrset != NULL);
@@ -261,7 +334,8 @@ static int knot_ddns_check_exist(const knot_zone_contents_t *zone,
 /*----------------------------------------------------------------------------*/
 
 static int knot_ddns_check_exist_full(const knot_zone_contents_t *zone,
-                                      const knot_rrset_t *rrset, uint8_t *rcode)
+                                      const knot_rrset_t *rrset, 
+                                      knot_rcode_t *rcode)
 {
 	assert(zone != NULL);
 	assert(rrset != NULL);
@@ -305,7 +379,8 @@ static int knot_ddns_check_exist_full(const knot_zone_contents_t *zone,
 /*----------------------------------------------------------------------------*/
 
 static int knot_ddns_check_not_exist(const knot_zone_contents_t *zone,
-                                     const knot_rrset_t *rrset, uint8_t *rcode)
+                                     const knot_rrset_t *rrset, 
+                                     knot_rcode_t *rcode)
 {
 	assert(zone != NULL);
 	assert(rrset != NULL);
@@ -322,23 +397,15 @@ static int knot_ddns_check_not_exist(const knot_zone_contents_t *zone,
 	}
 
 	const knot_node_t *node;
-	const knot_rrset_t *found;
 
 	node = knot_zone_contents_find_node(zone, knot_rrset_owner(rrset));
 	if (node == NULL) {
 		return KNOT_EOK;
-	} else if ((found = knot_node_rrset(node, knot_rrset_type(rrset)))
-	            == NULL) {
+	} else if (knot_node_rrset(node, knot_rrset_type(rrset)) == NULL) {
 		return KNOT_EOK;
-	} else {
-		// do not have to compare the header, it is already done
-		assert(knot_rrset_type(found) == knot_rrset_type(rrset));
-		assert(knot_dname_compare(knot_rrset_owner(found),
-		                          knot_rrset_owner(rrset)) == 0);
-		if (knot_rrset_compare_rdata(found, rrset) <= 0) {
-			return KNOT_EOK;
-		}
 	}
+	
+	/* RDATA is always empty for simple RRset checks. */
 
 	*rcode = KNOT_RCODE_YXRRSET;
 	return KNOT_EPREREQ;
@@ -347,7 +414,8 @@ static int knot_ddns_check_not_exist(const knot_zone_contents_t *zone,
 /*----------------------------------------------------------------------------*/
 
 static int knot_ddns_check_in_use(const knot_zone_contents_t *zone,
-                                  const knot_dname_t *dname, uint8_t *rcode)
+                                  const knot_dname_t *dname, 
+                                  knot_rcode_t *rcode)
 {
 	assert(zone != NULL);
 	assert(dname != NULL);
@@ -376,7 +444,8 @@ static int knot_ddns_check_in_use(const knot_zone_contents_t *zone,
 /*----------------------------------------------------------------------------*/
 
 static int knot_ddns_check_not_in_use(const knot_zone_contents_t *zone,
-                                      const knot_dname_t *dname, uint8_t *rcode)
+                                      const knot_dname_t *dname, 
+                                      knot_rcode_t *rcode)
 {
 	assert(zone != NULL);
 	assert(dname != NULL);
@@ -405,10 +474,13 @@ static int knot_ddns_check_not_in_use(const knot_zone_contents_t *zone,
 /* API functions                                                              */
 /*----------------------------------------------------------------------------*/
 
-int knot_ddns_check_zone(const knot_zone_t *zone, knot_packet_t *query,
-                         uint8_t *rcode)
+int knot_ddns_check_zone(const knot_zone_contents_t *zone, 
+                         const knot_packet_t *query, knot_rcode_t *rcode)
 {
 	if (zone == NULL || query == NULL || rcode == NULL) {
+		if (rcode != NULL) {
+			*rcode = KNOT_RCODE_SERVFAIL;
+		}
 		return KNOT_EINVAL;
 	}
 
@@ -417,18 +489,8 @@ int knot_ddns_check_zone(const knot_zone_t *zone, knot_packet_t *query,
 		return KNOT_EMALF;
 	}
 
-	if(!knot_zone_contents(zone)) {
-		*rcode = KNOT_RCODE_REFUSED;
-		return KNOT_ENOZONE;
-	}
-
-	// 1) check if the zone is master or slave
-	if (!knot_zone_is_master(zone)) {
-		return KNOT_EBADZONE;
-	}
-
-	// 2) check zone CLASS
-	if (knot_zone_contents_class(knot_zone_contents(zone)) !=
+	// check zone CLASS
+	if (knot_zone_contents_class(zone) !=
 	    knot_packet_qclass(query)) {
 		*rcode = KNOT_RCODE_NOTAUTH;
 		return KNOT_ENOZONE;
@@ -439,8 +501,8 @@ int knot_ddns_check_zone(const knot_zone_t *zone, knot_packet_t *query,
 
 /*----------------------------------------------------------------------------*/
 
-int knot_ddns_process_prereqs(knot_packet_t *query,
-                              knot_ddns_prereq_t **prereqs, uint8_t *rcode)
+int knot_ddns_process_prereqs(const knot_packet_t *query,
+                              knot_ddns_prereq_t **prereqs, knot_rcode_t *rcode)
 {
 	/*! \todo Consider not parsing the whole packet at once, but
 	 *        parsing one RR at a time - could save some memory and time.
@@ -449,6 +511,8 @@ int knot_ddns_process_prereqs(knot_packet_t *query,
 	if (query == NULL || prereqs == NULL || rcode == NULL) {
 		return KNOT_EINVAL;
 	}
+	
+	dbg_ddns("Processing prerequisities.\n");
 
 	// allocate space for the prerequisities
 	*prereqs = (knot_ddns_prereq_t *)calloc(1, sizeof(knot_ddns_prereq_t));
@@ -478,9 +542,11 @@ int knot_ddns_process_prereqs(knot_packet_t *query,
 /*----------------------------------------------------------------------------*/
 
 int knot_ddns_check_prereqs(const knot_zone_contents_t *zone,
-                            knot_ddns_prereq_t **prereqs, uint8_t *rcode)
+                            knot_ddns_prereq_t **prereqs, knot_rcode_t *rcode)
 {
 	int i, ret;
+	
+	dbg_ddns("Checking 'exist' prerequisities.\n");
 
 	for (i = 0; i < (*prereqs)->exist_count; ++i) {
 		ret = knot_ddns_check_exist(zone, (*prereqs)->exist[i], rcode);
@@ -489,6 +555,7 @@ int knot_ddns_check_prereqs(const knot_zone_contents_t *zone,
 		}
 	}
 
+	dbg_ddns("Checking 'exist full' prerequisities.\n");
 	for (i = 0; i < (*prereqs)->exist_full_count; ++i) {
 		ret = knot_ddns_check_exist_full(zone,
 		                                (*prereqs)->exist_full[i],
@@ -498,6 +565,7 @@ int knot_ddns_check_prereqs(const knot_zone_contents_t *zone,
 		}
 	}
 
+	dbg_ddns("Checking 'not exist' prerequisities.\n");
 	for (i = 0; i < (*prereqs)->not_exist_count; ++i) {
 		ret = knot_ddns_check_not_exist(zone, (*prereqs)->not_exist[i],
 		                                rcode);
@@ -506,6 +574,7 @@ int knot_ddns_check_prereqs(const knot_zone_contents_t *zone,
 		}
 	}
 
+	dbg_ddns("Checking 'in use' prerequisities.\n");
 	for (i = 0; i < (*prereqs)->in_use_count; ++i) {
 		ret = knot_ddns_check_in_use(zone, (*prereqs)->in_use[i],
 		                             rcode);
@@ -514,6 +583,7 @@ int knot_ddns_check_prereqs(const knot_zone_contents_t *zone,
 		}
 	}
 
+	dbg_ddns("Checking 'not in use' prerequisities.\n");
 	for (i = 0; i < (*prereqs)->not_in_use_count; ++i) {
 		ret = knot_ddns_check_not_in_use(zone,
 		                                 (*prereqs)->not_in_use[i],
@@ -529,10 +599,15 @@ int knot_ddns_check_prereqs(const knot_zone_contents_t *zone,
 /*----------------------------------------------------------------------------*/
 
 static int knot_ddns_check_update(const knot_rrset_t *rrset,
-                                  const knot_packet_t *query, uint8_t *rcode)
+                                  const knot_packet_t *query, 
+                                  knot_rcode_t *rcode)
 {
-	if (!knot_dname_is_subdomain(knot_rrset_owner(rrset),
-	                             knot_packet_qname(query))) {
+	/* Accept both subdomain and dname match. */
+	dbg_ddns("Checking UPDATE packet.\n");
+	const knot_dname_t *owner = knot_rrset_owner(rrset);
+	const knot_dname_t *qname = knot_packet_qname(query);
+	int is_sub = knot_dname_is_subdomain(owner, qname);
+	if (!is_sub && knot_dname_compare(owner, qname) != 0) {
 		*rcode = KNOT_RCODE_NOTZONE;
 		return KNOT_EBADZONE;
 	}
@@ -565,8 +640,9 @@ static int knot_ddns_check_update(const knot_rrset_t *rrset,
 
 /*----------------------------------------------------------------------------*/
 
-int knot_ddns_process_update(knot_packet_t *query,
-                             knot_changeset_t **changeset, uint8_t *rcode)
+int knot_ddns_process_update(const knot_zone_contents_t *zone,
+			     const knot_packet_t *query,
+                             knot_changeset_t *changeset, knot_rcode_t *rcode)
 {
 	// just put all RRSets from query's Authority section
 	// it will be distinguished when applying to the zone
@@ -575,63 +651,1739 @@ int knot_ddns_process_update(knot_packet_t *query,
 		return KNOT_EINVAL;
 	}
 
-	*changeset = (knot_changeset_t *)calloc(1, sizeof(knot_changeset_t));
-	CHECK_ALLOC_LOG(*changeset, KNOT_ENOMEM);
+	int ret = KNOT_EOK;
+
+	/* Copy base SOA query. */
+	const knot_rrset_t *soa = knot_node_rrset(knot_zone_contents_apex(zone),
+						  KNOT_RRTYPE_SOA);
+	knot_rrset_t *soa_begin = NULL;
+	knot_rrset_t *soa_end = NULL;
+	ret = knot_rrset_deep_copy(soa, &soa_begin, 0);
+	if (ret == KNOT_EOK) {
+		knot_changeset_store_soa(&changeset->soa_from,
+		                         &changeset->serial_from, soa_begin);
+	} else {
+		*rcode = KNOT_RCODE_SERVFAIL;
+		return ret;
+	}
 
-	int ret;
+	/* Current SERIAL */
+	int64_t sn = knot_rdata_soa_serial(knot_rrset_rdata(soa_begin));
+	int64_t sn_new;
+	/* Incremented SERIAL
+	 * We must set it now to be able to compare SERIAL from SOAs in the
+	 * UPDATE to it. Although we do not have the new SOA yet.
+	 */
+	if (sn > -1) {
+		sn_new = (uint32_t)sn + 1;
+	} else {
+		*rcode = KNOT_RCODE_SERVFAIL;
+		return ret;
+	}
+
+	const knot_rrset_t *rrset = NULL;
+	knot_rrset_t *rrset_copy = NULL;
 
+	dbg_ddns("Processing UPDATE section.\n");
 	for (int i = 0; i < knot_packet_authority_rrset_count(query); ++i) {
 
-		const knot_rrset_t *rrset =
-				knot_packet_authority_rrset(query, i);
+		rrset = knot_packet_authority_rrset(query, i);
 
 		ret = knot_ddns_check_update(rrset, query, rcode);
 		if (ret != KNOT_EOK) {
+			dbg_ddns("Failed to check update RRSet:%s\n",
+			                knot_strerror(ret));
 			return ret;
 		}
 
-		ret = knot_ddns_add_update(*changeset, rrset,
-		                          knot_packet_qclass(query));
+		ret = knot_ddns_add_update(changeset, rrset,
+		                          knot_packet_qclass(query),
+		                          &rrset_copy);
 
 		if (ret != KNOT_EOK) {
 			dbg_ddns("Failed to add update RRSet:%s\n",
 			                knot_strerror(ret));
 			*rcode = (ret == KNOT_EMALF) ? KNOT_RCODE_FORMERR
 			                             : KNOT_RCODE_SERVFAIL;
-			knot_free_changeset(changeset);
 			return ret;
 		}
+
+		/* Check if the added record is SOA. If yes, check the SERIAL.
+		 * If this record should cause the SOA to be replaced in the
+		 * zone, use it as the ending SOA.
+		 *
+		 * Also handle cases where there are multiple SOAs to be added
+		 * in the same UPDATE. The one with the largest SERIAL should
+		 * be used.
+		 *
+		 * TODO: If there are more SOAs in the UPDATE one after another,
+		 *       the ddns_add_update() function will merge them into a
+		 *       RRSet. This should be handled somehow.
+		 */
+		if (knot_rrset_type(rrset) == KNOT_RRTYPE_SOA
+		    && ns_serial_compare(knot_rdata_soa_serial(
+		                                 knot_rrset_rdata(rrset)),
+		                         sn_new) > 0) {
+			sn_new = knot_rdata_soa_serial(knot_rrset_rdata(rrset));
+			soa_end = (knot_rrset_t *)rrset_copy;
+		}
 	}
 
-	return KNOT_EOK;
+	/* Ending SOA */
+	if (soa_end == NULL) {
+		/* If not set */
+		assert(sn_new == (uint32_t)sn + 1);
+		ret = knot_rrset_deep_copy(soa, &soa_end, 1);
+		knot_rdata_t *rd = knot_rrset_get_rdata(soa_end);
+		knot_rdata_soa_serial_set(rd, sn_new);
+	}
+
+	knot_changeset_store_soa(&changeset->soa_to,
+	                         &changeset->serial_to,
+	                         soa_end);
+
+	return ret;
 }
 
 /*----------------------------------------------------------------------------*/
 
 void knot_ddns_prereqs_free(knot_ddns_prereq_t **prereq)
 {
+	dbg_ddns("Freeing prerequisities.\n");
+
 	int i;
 
 	for (i = 0; i < (*prereq)->exist_count; ++i) {
 		knot_rrset_deep_free(&(*prereq)->exist[i], 1, 1, 1);
 	}
+	free((*prereq)->exist);
 
 	for (i = 0; i < (*prereq)->exist_full_count; ++i) {
 		knot_rrset_deep_free(&(*prereq)->exist_full[i], 1, 1, 1);
 	}
+	free((*prereq)->exist_full);
 
 	for (i = 0; i < (*prereq)->not_exist_count; ++i) {
 		knot_rrset_deep_free(&(*prereq)->not_exist[i], 1, 1, 1);
 	}
+	free((*prereq)->not_exist);
 
 	for (i = 0; i < (*prereq)->in_use_count; ++i) {
 		knot_dname_free(&(*prereq)->in_use[i]);
 	}
+	free((*prereq)->in_use);
 
 	for (i = 0; i < (*prereq)->not_in_use_count; ++i) {
 		knot_dname_free(&(*prereq)->not_in_use[i]);
 	}
+	free((*prereq)->not_in_use);
 
 	free(*prereq);
 	*prereq = NULL;
 }
+
+/*----------------------------------------------------------------------------*/
+/* New DDNS processing                                                      - */
+/*----------------------------------------------------------------------------*/
+
+static int knot_ddns_check_remove_rr2(knot_changeset_t *changeset,
+                                      const knot_dname_t *owner,
+                                      uint16_t type, const knot_rdata_t *rdata,
+                                      knot_rrset_t ***removed,
+                                      size_t *removed_count)
+{
+	assert(changeset != NULL);
+	assert(removed != NULL);
+	assert(removed_count != NULL);
+
+	*removed_count = 0;
+	*removed = (knot_rrset_t **)malloc(changeset->add_count
+	                                  * sizeof(knot_rrset_t *));
+	if (*removed == NULL) {
+		return KNOT_ENOMEM;
+	}
+
+	knot_rrset_t *remove = NULL;
+
+	/*
+	 * We assume that each RR in the ADD section of the changeset is in its
+	 * own RRSet. It should be as this is how they are stored there by the
+	 * ddns_process_add() function.
+	 */
+
+	dbg_ddns_verb("Removing possible redundant RRs from changeset.\n");
+	for (int i = 0; i < changeset->add_count; ++i) {
+		// Removing RR(s) from this owner
+		if (knot_dname_compare(knot_rrset_owner(changeset->add[i]),
+		                       owner) == 0) {
+			// Removing one or all RRSets
+			if (rdata == NULL
+			    && (type == knot_rrset_type(changeset->add[i])
+			        || type == KNOT_RRTYPE_ANY)) {
+				dbg_ddns_detail("Removing one or all RRSets\n");
+					remove = knot_changeset_remove_rr(
+					              changeset->add,
+					              &changeset->add_count, i);
+			} else if (type == knot_rrset_type(changeset->add[i])) {
+				// Removing specific RR
+				assert(rdata != NULL);
+
+				knot_rrtype_descriptor_t *desc =
+					knot_rrtype_descriptor_by_type(type);
+
+				// We must check if the RDATA match
+				if (knot_rdata_compare(rdata,
+				         knot_rrset_rdata(changeset->add[i]),
+				         desc->wireformat)) {
+					remove = knot_changeset_remove_rr(
+					              changeset->add,
+					              &changeset->add_count, i);
+				}
+			}
+
+			dbg_ddns_detail("Removed RRSet from chgset:\n");
+			knot_rrset_dump(remove, 0);
+			(*removed)[(*removed_count)++] = remove;
+		}
+	}
+
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
+static void knot_ddns_check_add_rr(knot_changeset_t *changeset,
+                                   const knot_rrset_t *rr,
+                                   knot_rrset_t **removed)
+{
+	assert(changeset != NULL);
+	assert(rr != NULL);
+	assert(removed != NULL);
+
+	*removed = NULL;
+	
+	dbg_ddns_verb("Removing possible redundant RRs from changeset.\n");
+	for (int i = 0; i < changeset->remove_count; ++i)  {
+		/* Just check exact match, the changeset contains only 
+		 * whole RRs that have been removed.
+		 */
+		if (knot_rrset_match(rr, changeset->remove[i],
+		                     KNOT_RRSET_COMPARE_WHOLE) == 1) {
+			*removed = knot_changeset_remove_rr(
+			                        changeset->remove,
+			                        &changeset->remove_count, i);
+			dbg_ddns_detail("Removed RRSet from chgset:\n");
+			knot_rrset_dump(*removed, 0);
+			break;
+		}
+	}
+}
+
+/*----------------------------------------------------------------------------*/
+
+static int knot_ddns_rr_is_nsec3(const knot_rrset_t *rr)
+{
+	assert(rr != NULL);
+
+	if ((knot_rrset_type(rr) == KNOT_RRTYPE_NSEC3)
+	    || (knot_rrset_type(rr) == KNOT_RRTYPE_RRSIG
+	        && knot_rrset_rdata(rr) 
+	        && knot_rdata_rrsig_type_covered(knot_rrset_rdata(rr))
+	            == KNOT_RRTYPE_NSEC3))
+	{
+		dbg_ddns_detail("This is NSEC3-related RRSet.\n");
+		return 1;
+	} else {
+		return 0;
+	}
+}
+
+/*----------------------------------------------------------------------------*/
+/*! \note Copied from xfrin_add_new_node(). */
+static knot_node_t *knot_ddns_add_new_node(knot_zone_contents_t *zone,
+                                           knot_dname_t *owner, int is_nsec3)
+{
+	assert(zone != NULL);
+	assert(owner != NULL);
+
+	knot_node_t *node = knot_node_new(owner, NULL, 0);
+	if (node == NULL) {
+		dbg_xfrin("Failed to create a new node.\n");
+		return NULL;
+	}
+
+	int ret = 0;
+
+	// insert the node into zone structures and create parents if
+	// necessary
+	if (is_nsec3) {
+		ret = knot_zone_contents_add_nsec3_node(zone, node, 1, 0, 1);
+	} else {
+		ret = knot_zone_contents_add_node(zone, node, 1, 0, 1);
+	}
+	if (ret != KNOT_EOK) {
+		dbg_xfrin("Failed to add new node to zone contents.\n");
+		knot_node_free(&node);
+		return NULL;
+	}
+
+	/*!
+	 * \note It is not needed to set the previous node, we will do this
+	 *       in adjusting after the transfer.
+	 */
+	assert(zone->zone != NULL);
+	//knot_node_set_zone(node, zone->zone);
+	assert(node->zone == zone->zone);
+
+	return node;
+}
+
+/*----------------------------------------------------------------------------*/
+
+static knot_node_t *knot_ddns_get_node(knot_zone_contents_t *zone,
+                                       const knot_rrset_t *rr)
+{
+	assert(zone != NULL);
+	assert(rr != NULL);
+
+	knot_node_t *node = NULL;
+	knot_dname_t *owner = knot_rrset_get_owner(rr);
+
+	dbg_ddns_detail("Searching for node...\n");
+	if (knot_ddns_rr_is_nsec3(rr)) {
+		node = knot_zone_contents_get_nsec3_node(zone, owner);
+	} else {
+		node = knot_zone_contents_get_node(zone, owner);
+	}
+
+	return node;
+}
+
+/*----------------------------------------------------------------------------*/
+
+static int knot_ddns_process_add_cname(knot_node_t *node, 
+                                       const knot_rrset_t *rr,
+                                       knot_changeset_t *changeset,
+                                       knot_changes_t *changes)
+{
+	assert(node != NULL);
+	assert(rr != NULL);
+	assert(changeset != NULL);
+	assert(changes != NULL);
+	
+	dbg_ddns_detail("Adding CNAME RR.\n");
+	
+	int ret = 0;
+	
+	/* Get the current CNAME RR from the node. */
+	knot_rrset_t *removed = knot_node_get_rrset(node, KNOT_RRTYPE_CNAME);
+	
+	if (removed != NULL) {
+		/* If they are identical, ignore. */
+		if (knot_rrset_match(removed, rr, KNOT_RRSET_COMPARE_WHOLE)
+		    == 1) {
+			dbg_ddns_verb("CNAME identical to one in the node.\n");
+			return 1;
+		}
+		
+		/*! \note
+		 * Together with the removed CNAME we remove also its RRSIGs as
+		 * they would not be valid for the new CNAME anyway.
+		 *
+		 * \todo Document!!
+		 */
+		
+		/* b) Store it to 'changes', together with its RRSIGs. */
+		ret = knot_changes_add_old_rrsets(&removed, 1, changes, 1);
+		if (ret != KNOT_EOK) {
+			dbg_ddns("Failed to add removed RRSet to "
+			         "'changes': %s\n", knot_strerror(ret));
+			return ret;
+		}
+
+		/* c) And remove it from the node. */
+		(void)knot_node_remove_rrset(node, KNOT_RRTYPE_CNAME);
+		
+		/* d) Check if this CNAME was not previously added by
+		 *    the UPDATE. If yes, remove it from the ADD 
+		 *    section and do not add it to the REMOVE section.
+		 */
+		knot_rrset_t **from_chgset = NULL;
+		size_t from_chgset_count = 0;
+		ret = knot_ddns_check_remove_rr2(
+		                   changeset, knot_rrset_owner(removed),
+		                   KNOT_RRTYPE_CNAME, knot_rrset_rdata(removed),
+		                   &from_chgset, &from_chgset_count);
+		if (ret != KNOT_EOK) {
+			dbg_ddns("Failed to remove possible redundant "
+			         "RRs from ADD section: %s.\n", 
+			         knot_strerror(ret));
+			free(from_chgset);
+			return ret;
+		}
+	
+		assert(from_chgset_count <= 1);
+	
+		if (from_chgset_count == 1) {
+			/* Just delete the RRSet. */
+			knot_rrset_deep_free(&(from_chgset[0]), 1, 1, 1);
+			/* Okay, &(from_chgset[0]) is basically equal to just
+			 * from_chgset, but it's more clear this way that we are
+			 * deleting the first RRSet in the array ;-)
+			 */
+		} else {
+			/* Otherwise copy the removed CNAME and add it 
+			 * to the REMOVE section.
+			 */
+			knot_rrset_t *removed_copy;
+			ret = knot_rrset_deep_copy(removed, 
+			                           &removed_copy, 1);
+			if (ret != KNOT_EOK) {
+				dbg_ddns("Failed to copy removed RRSet:"
+				         " %s\n", knot_strerror(ret));
+				free(from_chgset);
+				return ret;
+			}
+			
+			ret = knot_changeset_add_rrset(
+				&changeset->remove,
+				&changeset->remove_count,
+				&changeset->remove_allocated,
+				removed_copy);
+			if (ret != KNOT_EOK) {
+				knot_rrset_deep_free(&removed_copy, 
+				                     1, 1, 1);
+				dbg_ddns("Failed to add removed CNAME "
+				         "to changeset: %s\n",
+				         knot_strerror(ret));
+				free(from_chgset);
+				return ret;
+			}
+		}
+		free(from_chgset);
+	} else if (knot_node_rrset_count(node) != 0) {
+		/* 2) Other occupied node => ignore. */
+		return 1;
+	}
+	
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
+static int knot_ddns_process_add_soa(knot_node_t *node, 
+                                     const knot_rrset_t *rr,
+                                     knot_changes_t *changes)
+{
+	assert(node != NULL);
+	assert(rr != NULL);
+	assert(changes != NULL);
+	
+	dbg_ddns_detail("Adding SOA RR.\n");
+	
+	int ret = 0;
+	
+	/*
+	 * Just remove the SOA from the node, together with its RRSIGs. 
+	 * Adding the RR is done in the caller function. Note that only SOA
+	 * with larger SERIAL than the current one will get to these functions,
+	 * so we don't have to check the SERIALS again. But an assert won't
+	 * hurt.
+	 */
+	
+	/* Get the current SOA RR from the node. */
+	knot_rrset_t *removed = knot_node_get_rrset(node, KNOT_RRTYPE_SOA);
+	
+	if (removed != NULL) {
+		dbg_ddns_detail("Found SOA in the node.\n");
+		/* If they are identical, ignore. */
+		if (knot_rrset_match(removed, rr, KNOT_RRSET_COMPARE_WHOLE)
+		    == 1) {
+			dbg_ddns_detail("Old and new SOA identical.\n");
+			return 1;
+		}
+		
+		/* Check that the serial is indeed larger than the current one*/
+		assert(ns_serial_compare(knot_rdata_soa_serial(
+		                                 knot_rrset_rdata(removed)),
+		                         knot_rdata_soa_serial(
+		                                 knot_rrset_rdata(rr))) < 0);
+		
+		/* 1) Store it to 'changes', together with its RRSIGs. */
+		ret = knot_changes_add_old_rrsets(
+		                        &removed, 1, changes, 1);
+		if (ret != KNOT_EOK) {
+			dbg_ddns("Failed to add removed RRSet to "
+			         "'changes': %s\n", knot_strerror(ret));
+			return ret;
+		}
+
+		/* 2) And remove it from the node. */
+		(void)knot_node_remove_rrset(node, KNOT_RRTYPE_SOA);
+		
+		/* No changeset processing needed in this case. */
+	} else {
+		dbg_ddns_detail("No SOA in node, ignoring.\n");
+		/* If there is no SOA in the node, ignore. */
+		return 1;
+	}
+	
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
+static int knot_ddns_add_rr_new_normal(knot_node_t *node, knot_rrset_t *rr_copy,
+                                       knot_changes_t *changes)
+{
+	assert(node != NULL);
+	assert(rr_copy != NULL);
+	assert(changes != NULL);
+	
+	dbg_ddns_verb("Adding normal RR.\n");
+	
+	/* Add the RRSet to 'changes'. */
+	int ret = knot_changes_add_new_rrsets(&rr_copy, 1, changes, 1);
+	if (ret != KNOT_EOK) {
+		knot_rrset_deep_free(&rr_copy, 1, 1, 1);
+		dbg_ddns("Failed to store copy of the added RR: "
+		         "%s\n", knot_strerror(ret));
+		return ret;
+	}
+	
+	/* Add the RRSet to the node. */
+	ret = knot_node_add_rrset(node, rr_copy, 0);
+	if (ret != KNOT_EOK) {
+		dbg_ddns("Failed to add RR to node: %s\n", knot_strerror(ret));
+		return ret;
+	}
+	
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
+static int knot_ddns_add_rr_new_rrsig(knot_node_t *node, knot_rrset_t *rr_copy,
+                                      knot_changes_t *changes, 
+                                      uint16_t type_covered)
+{
+	assert(node != NULL);
+	assert(rr_copy != NULL);
+	assert(changes != NULL);
+	
+	dbg_ddns_verb("Adding RRSIG RR.\n");
+	
+	/* Create RRSet to be covered by the RRSIG. */
+	knot_rrset_t *covered_rrset = knot_rrset_new(
+	                        knot_rrset_get_owner(rr_copy), type_covered,
+	                        knot_rrset_class(rr_copy),
+	                        knot_rrset_ttl(rr_copy));
+	if (covered_rrset == NULL) {
+		dbg_ddns("Failed to create RRSet to be covered"
+			 " by the UPDATE RRSIG RR.\n");
+		knot_rrset_deep_free(&rr_copy, 1, 1, 1);
+		return KNOT_ENOMEM;
+	}
+	
+	/* Add the RRSet to the node. */
+	int ret = knot_node_add_rrset(node, covered_rrset, 0);
+	if (ret != KNOT_EOK) {
+		dbg_ddns("Failed to add the RRSet to be covered to the node: %s"
+		         ".\n", knot_strerror(ret));
+		knot_rrset_deep_free(&rr_copy, 1, 1, 1);
+		knot_rrset_deep_free(&covered_rrset, 1, 1, 1);
+		return KNOT_ENOMEM;
+	}
+	
+	/* Add the RRSet to 'changes'. */
+	ret = knot_changes_add_new_rrsets(&covered_rrset, 1, changes, 0);
+	if (ret != KNOT_EOK) {
+		dbg_xfrin("Failed to add new RRSet (covered) to list: %s.\n",
+		          knot_strerror(ret));
+		knot_rrset_deep_free(&rr_copy, 1, 1, 1);
+		knot_rrset_deep_free(&covered_rrset, 1, 1, 1);
+		return ret;
+	}
+
+	/* Add the RRSIG RRSet to 'changes'. */
+	ret = knot_changes_add_new_rrsets(&rr_copy, 1, changes, 1);
+	if (ret != KNOT_EOK) {
+		knot_rrset_deep_free(&rr_copy, 1, 1, 1);
+		dbg_ddns("Failed to store copy of the added RRSIG: %s\n",
+			 knot_strerror(ret));
+		return ret;
+	}
+	
+	/* Add the RRSIG RRSet to the covered RRSet. */
+	ret = knot_rrset_add_rrsigs(covered_rrset, rr_copy, 
+	                            KNOT_RRSET_DUPL_SKIP);
+	if (ret != KNOT_EOK) {
+		dbg_ddns("Failed to add RRSIG RR to the covered RRSet.\n");
+		return ret;
+	}
+	
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
+static int knot_ddns_add_rr_merge_normal(knot_rrset_t *node_rrset_copy,
+                                         knot_rrset_t **rr_copy)
+{
+	assert(node_rrset_copy != NULL);
+	assert(rr_copy != NULL);
+	assert(*rr_copy != NULL);
+	
+	dbg_ddns_verb("Merging normal RR to existing RRSet.\n");
+	
+	/* In case the RRSet is empty (and only remained there because 
+	 * of the RRSIGs) it may happen that the TTL may be different 
+	 * than that of he new RRs. Update the TTL according to the 
+	 * first RR.
+	 */	
+	if (knot_rrset_rdata(node_rrset_copy) == NULL
+	    && knot_rrset_ttl(node_rrset_copy) 
+	       != knot_rrset_ttl(*rr_copy)) {
+		knot_rrset_set_ttl(node_rrset_copy, 
+		                   knot_rrset_ttl(*rr_copy));
+	}
+
+	int rdata_in_copy = knot_rrset_rdata_rr_count(*rr_copy);
+	int ret = knot_rrset_merge_no_dupl((void **)&node_rrset_copy, 
+	                                   (void **)rr_copy);
+	dbg_ddns_detail("Merge returned: %d\n", ret);
+
+	if (ret < 0) {
+		dbg_ddns("Failed to merge UPDATE RR to node RRSet: %s."
+		         "\n", knot_strerror(ret));
+		return ret;
+	}
+
+	knot_rrset_free(rr_copy);
+
+	if (rdata_in_copy == ret) {
+		/* All RDATA have been removed, because they were duplicates
+		 * or there were none (0). In general this means, that no
+		 * change was made.
+		 */
+		return 1;
+	}
+	
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
+static int knot_ddns_add_rr_merge_rrsig(knot_rrset_t *node_rrset_copy,
+                                        knot_rrset_t **rr_copy,
+                                        knot_changes_t *changes)
+{
+	assert(node_rrset_copy != NULL);
+	assert(rr_copy != NULL);
+	assert(*rr_copy != NULL);
+	assert(changes != NULL);
+	
+	dbg_ddns_verb("Adding RRSIG RR to existing RRSet.\n");
+	
+	knot_rrset_t *rrsigs_old = knot_rrset_get_rrsigs(node_rrset_copy);
+	int ret = 0;
+	
+	if (rrsigs_old != NULL) {
+		/* If there is an RRSIG RRSet already, copy it too. */
+		knot_rrset_t *rrsigs_copy = NULL;
+		ret = xfrin_copy_old_rrset(rrsigs_old, &rrsigs_copy,
+		                           changes, 1);
+		if (ret != KNOT_EOK) {
+			dbg_ddns("Failed to copy RRSIG RRSet: "
+			         "%s\n", knot_strerror(ret));
+			return ret;
+		}
+		
+		/* Replace the RRSIGs by the copy. */
+		ret = knot_rrset_set_rrsigs(node_rrset_copy, rrsigs_copy);
+		if (ret != KNOT_EOK) {
+			dbg_ddns("Failed to replace RRSIGs in "
+			         "the RRSet: %s\n", 
+			         knot_strerror(ret));
+			return ret;
+		}
+		
+		/* Merge the UPDATE RR to the copied RRSIG
+		 * RRSet.
+		 */
+		dbg_ddns_detail("Merging RRSIG to the one in the RRSet.\n");
+
+		int rdata_in_copy = knot_rrset_rdata_rr_count(*rr_copy);
+		ret = knot_rrset_merge_no_dupl(
+		    (void **)&rrsigs_copy, (void **)rr_copy);
+		if (ret < 0) {
+			dbg_xfrin("Failed to merge UPDATE RRSIG to copy: %s.\n",
+			          knot_strerror(ret));
+			return KNOT_ERROR;
+		}
+		
+		knot_rrset_free(rr_copy);
+
+		if (rdata_in_copy == ret) {
+			/* All RDATA have been removed, because they were
+			 * duplicates or there were none (0). In general this
+			 * means, that no change was made.
+			 */
+			return 1;
+		}
+	} else {
+		/* If there is no RRSIG RRSet yet, just add the
+		 * UPDATE RR to the copied covered RRSet.
+		 */
+		/* Add the RRSet to 'changes'. */
+		ret = knot_changes_add_new_rrsets(rr_copy, 1, changes, 1);
+		if (ret != KNOT_EOK) {
+			dbg_ddns("Failed to store copy of the added RR: %s\n",
+			         knot_strerror(ret));
+			return ret;
+		}
+		
+		/* Add the RRSet to the covered RRSet. */
+		ret = knot_rrset_add_rrsigs(node_rrset_copy, *rr_copy,
+		                            KNOT_RRSET_DUPL_SKIP);
+		if (ret != KNOT_EOK) {
+			dbg_ddns("Failed to add RRSIG RR to the"
+			         " covered RRSet.\n");
+			return ret;
+		}
+	}
+	
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+/*!
+ * \todo We should check, how it's possible that IXFR is not leaking due to the
+ * same issue with merge. Or maybe it is, we should try it!!
+ */
+
+/*----------------------------------------------------------------------------*/
+
+static int knot_ddns_add_rr(knot_node_t *node, const knot_rrset_t *rr,
+                            knot_changes_t *changes, knot_rrset_t **rr_copy)
+{
+	assert(node != NULL);
+	assert(rr != NULL);
+	assert(changes != NULL);
+	assert(rr_copy != NULL);
+	
+	/* Copy the RRSet from the packet. */
+	//knot_rrset_t *rr_copy;
+	int ret = knot_rrset_deep_copy(rr, rr_copy, 1);
+	if (ret != KNOT_EOK) {
+		dbg_ddns("Failed to copy RR: %s\n", knot_strerror(ret));
+		return ret;
+	}
+	
+	uint16_t type = knot_rrset_type(rr);
+	uint16_t type_covered = (type == KNOT_RRTYPE_RRSIG) 
+	                ? knot_rdata_rrsig_type_covered(knot_rrset_rdata(rr))
+	                : type;
+	
+	/* If the RR belongs to a RRSet already present in the node, we must
+	 * take this RRSet from the node, copy it, and merge this RR into it.
+	 *
+	 * This code is more or less copied from xfr-in.c.
+	 */
+	knot_rrset_t *node_rrset_copy = NULL;
+	ret = xfrin_copy_rrset(node, type_covered, &node_rrset_copy, changes, 
+	                       0);
+	
+	if (node_rrset_copy == NULL) {
+		/* No such RRSet in the node. Add the whole UPDATE RRSet. */
+		dbg_ddns_detail("Adding whole UPDATE RR to the zone.\n");
+		if (type_covered != type) {
+			/* Adding RRSIG. */
+			ret = knot_ddns_add_rr_new_rrsig(node, *rr_copy, 
+			                                 changes, type_covered);
+		} else {
+			ret = knot_ddns_add_rr_new_normal(node, *rr_copy, 
+			                                  changes);
+		}
+		if (ret != KNOT_EOK) {
+			dbg_ddns("Failed to add new RR to node.\n");
+			return ret;
+		}
+	} else {
+		/* We have copied the RRSet from the node. */
+dbg_ddns_exec_detail(
+		dbg_ddns_detail("Merging RR to an existing RRSet.\n");
+		knot_rrset_dump(node_rrset_copy, 1);
+		dbg_ddns_detail("New RR:\n");
+		knot_rrset_dump(*rr_copy, 0);
+);
+		
+		if (type_covered != type) {
+			/* Adding RRSIG. */
+			ret = knot_ddns_add_rr_merge_rrsig(node_rrset_copy,
+			                                   rr_copy, changes);
+		} else {
+			ret = knot_ddns_add_rr_merge_normal(node_rrset_copy,
+			                                    rr_copy);
+		}
+
+dbg_ddns_exec_detail(
+		dbg_ddns_detail("After merge:\n");
+		knot_rrset_dump(node_rrset_copy, 1);
+);
+
+		if (ret < KNOT_EOK) {
+			dbg_ddns("Failed to merge UPDATE RR to node RRSet.\n");
+			knot_rrset_deep_free(rr_copy, 1, 1, 1);
+			knot_rrset_deep_free(&node_rrset_copy, 1, 1, 1);
+			return ret;
+		}
+		
+		// save the new RRSet together with the new RDATA to 'changes'
+		// do not overwrite 'ret', it have to be returned
+		int r = knot_changes_add_new_rrsets(&node_rrset_copy, 1,
+		                                    changes, 1);
+		if (r != KNOT_EOK) {
+			dbg_ddns("Failed to store RRSet copy to 'changes'\n");
+			knot_rrset_deep_free(&node_rrset_copy, 1, 1, 1);
+			return r;
+		}
+	}
+	
+	assert(ret >= 0);
+	return ret;
+}
+
+/*----------------------------------------------------------------------------*/
+
+static int knot_ddns_final_soa_to_chgset(const knot_rrset_t *soa,
+                                         knot_changeset_t *changeset)
+{
+	assert(soa != NULL);
+	assert(changeset != NULL);
+	
+	knot_rrset_t *soa_copy = NULL;
+	int ret = knot_rrset_deep_copy(soa, &soa_copy, 1);
+	if (ret != KNOT_EOK) {
+		dbg_ddns("Failed to copy SOA RR to the changeset: "
+			 "%s\n", knot_strerror(ret));
+		return ret;
+	}
+	
+	knot_changeset_store_soa(&changeset->soa_to,
+	                         &changeset->serial_to,
+	                         soa_copy);
+	
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
+static int knot_ddns_add_rr_to_chgset(const knot_rrset_t *rr,
+                                      knot_changeset_t *changeset)
+{
+	assert(rr != NULL);
+	assert(changeset != NULL);
+	
+	int ret = 0;
+	knot_rrset_t *chgset_rr = NULL;
+	knot_ddns_check_add_rr(changeset, rr, &chgset_rr);
+	if (chgset_rr == NULL) {
+		ret = knot_rrset_deep_copy(rr, &chgset_rr, 1);
+		if (ret != KNOT_EOK) {
+			dbg_ddns("Failed to copy RR to the changeset: "
+				 "%s\n", knot_strerror(ret));
+			return ret;
+		}
+		/* No such RR in the changeset, add it. */
+		ret = knot_changeset_add_rrset(&changeset->add,
+		                               &changeset->add_count,
+		                               &changeset->add_allocated,
+		                               chgset_rr);
+		if (ret != KNOT_EOK) {
+			knot_rrset_deep_free(&chgset_rr, 1, 1, 1);
+			dbg_ddns("Failed to add RR to changeset: %s.\n",
+				 knot_strerror(ret));
+			return ret;
+		}
+	} else {
+		knot_rrset_deep_free(&chgset_rr, 1, 1, 1);
+	}
+	
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
+static int knot_ddns_process_add(const knot_rrset_t *rr,
+                                 knot_node_t *node,
+                                 knot_zone_contents_t *zone,
+                                 knot_changeset_t *changeset,
+                                 knot_changes_t *changes,
+                                 knot_rrset_t **rr_copy)
+{
+	assert(rr != NULL);
+	assert(zone != NULL);
+	assert(changeset != NULL);
+	assert(changes != NULL);
+	assert(rr_copy != NULL);
+	
+	dbg_ddns_verb("Adding RR.\n");
+
+	if (node == NULL) {
+		// create new node, connect it properly to the
+		// zone nodes
+		dbg_ddns_detail("Node not found. Creating new.\n");
+		node = knot_ddns_add_new_node(zone, knot_rrset_get_owner(rr),
+		                              knot_ddns_rr_is_nsec3(rr));
+		if (node == NULL) {
+			dbg_xfrin("Failed to create new node in zone.\n");
+			return KNOT_ERROR;
+		}
+	}
+	
+	uint16_t type = knot_rrset_type(rr);
+	*rr_copy = NULL;
+	int ret = 0;
+	
+	/*
+	 * First, rule out special cases: CNAME, SOA and adding to CNAME node.
+	 */
+	if (type == KNOT_RRTYPE_CNAME) {
+		/* 1) CNAME */
+		ret = knot_ddns_process_add_cname(node, rr, changeset, changes);
+	} else if (type == KNOT_RRTYPE_SOA) {
+		/* 2) SOA */
+		ret = knot_ddns_process_add_soa(node, rr, changes);
+	} else if (knot_node_rrset(node, KNOT_RRTYPE_CNAME) != NULL) {
+		/*
+		 * Adding RR to CNAME node. Ignore the UPDATE RR.
+		 *
+		 * TODO: This may or may not be according to the RFC, it's quite
+		 * unclear (see 3.4.2.2)
+		 */
+		return KNOT_EOK;
+	}
+	
+	if (ret == 1) {
+		dbg_ddns_detail("Ignoring the added RR.\n");
+		// Ignore
+		return KNOT_EOK;
+	} else if (ret != KNOT_EOK) {
+		dbg_ddns_detail("Adding RR failed.\n");
+		return ret;
+	}
+	
+	/*
+	 * In all other cases, the RR should just be added to the node.
+	 */
+	
+	/* Add the RRSet to the node (RRSIGs handled in the function). */
+	dbg_ddns_detail("Adding RR to the node.\n");
+	ret = knot_ddns_add_rr(node, rr, changes, rr_copy);
+	if (ret < 0) {
+		dbg_ddns("Failed to add RR to the node.\n");
+		return ret;
+	}
+	
+	/*
+	 * If adding SOA, it should not be stored in the changeset.
+	 * (This is done in the calling function, and the SOA is stored in the
+	 * soa_final field.)
+	 */
+	if (type == KNOT_RRTYPE_SOA) {
+		return KNOT_EOK;
+	}
+	
+	/* Add the RR to ADD section of the changeset. */
+	/* If the RR was previously removed, do not add it to the 
+	 * changeset, and remove the entry from the REMOVE section.
+	 *
+	 * If there was no change (i.e. all RDATA were duplicates), do not add
+	 * the RR to the changeset.
+	 */
+	if (ret == KNOT_EOK) {
+		dbg_ddns_detail("Adding RR to the changeset.\n");
+		ret = knot_ddns_add_rr_to_chgset(rr, changeset);
+		if (ret != KNOT_EOK) {
+			dbg_ddns("Failed to add the UPDATE RR to the changeset."
+			         "\n");
+			return ret;
+		}
+	}
+
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+/*!
+ * \todo Geez, this is soooooo long even I don't exactly know what it does...
+ *       Refactor!
+ */
+static int knot_ddns_process_rem_rr(const knot_rrset_t *rr,
+                                    knot_node_t *node,
+                                    knot_zone_contents_t *zone,
+                                    knot_changeset_t *changeset,
+                                    knot_changes_t *changes, uint16_t qclass)
+{
+	assert(rr != NULL);
+	assert(node != NULL);
+	assert(zone != NULL);
+	assert(changeset != NULL);
+	assert(changes != NULL);
+
+	uint16_t type = knot_rrset_type(rr);
+	dbg_ddns_verb("Removing one RR.\n");
+
+	/*
+	 * When doing changes to RRSets, we must:
+	 * 1) Copy the RRSet (same as in IXFR changeset applying, maybe the
+	 *    function xfrin_copy_rrset() may be used for this).
+	 * 2) Remove the RDATA (in this case only one). Check if it is not the
+	 *    last NS RR in the zone.
+	 * 3) Store the removed RDATA in 'changes'.
+	 * 4) If the RRSet is empty, remove it and store in 'changes'.
+	 * 5) Check redundant RRs in changeset.
+	 * 6) Store the RRSet containing the one RDATA in the changeset. We may
+	 *    use the RRSet from the packet for this - copy it, set CLASS
+	 *    and TTL.
+	 *
+	 * Special handling of RRSIGs is required in that the RRSet containing
+	 * them must be copied as well. However, copying of RRSet copies also
+	 * the RRSIGs, so copying the base RRSet is enough for both cases!
+	 */
+
+	assert(type != KNOT_RRTYPE_SOA);
+	int is_apex = knot_node_rrset(node, KNOT_RRTYPE_SOA) != NULL;
+	
+	/* If removing NS from an apex and there is only one NS left, ignore
+	 * this removal right away. We do not have to check if the RRs match:
+	 * - if they don't match, the removal will be ignored
+	 * - if they match, the last NS cannot be removed anyway.
+	 */
+	if (is_apex && type == KNOT_RRTYPE_NS
+	    && knot_rrset_rdata_rr_count(knot_node_rrset(node, type)) == 1) {
+		return KNOT_EOK;
+	}
+
+	/*
+	 * 1) Copy the RRSet.
+	 */
+	uint16_t type_to_copy = (type != KNOT_RRTYPE_RRSIG) ? type
+	                : knot_rdata_rrsig_type_covered(knot_rrset_rdata(rr));
+	knot_rrset_t *rrset_copy = NULL;
+	int ret = xfrin_copy_rrset(node, type_to_copy, &rrset_copy, changes, 1);
+	if (ret < 0) {
+		dbg_ddns("Failed to copy RRSet for removal: %s\n",
+		         knot_strerror(ret));
+		return ret;
+	}
+
+	if (rrset_copy == NULL) {
+		dbg_ddns_verb("RRSet not found.\n");
+		return KNOT_EOK;
+	}
+	
+	/*
+	 * Set some variables needed, according to the modified RR type.
+	 */
+	
+	int rdata_count;
+	knot_rrset_t *to_modify;
+	if (type == KNOT_RRTYPE_RRSIG) {
+		rdata_count = knot_rrset_rdata_rr_count(
+		                        knot_rrset_rrsigs(rrset_copy));
+		to_modify = knot_rrset_get_rrsigs(rrset_copy);
+	} else {
+		rdata_count = knot_rrset_rdata_rr_count(rrset_copy);
+		to_modify = rrset_copy;
+	}
+	
+	/*
+	 * 1.5) Prepare place for the removed RDATA.
+	 *      We don't know if there are some, but if this fails, at least we
+	 *      haven't removed them yet.
+	 */
+	ret = knot_changes_rdata_reserve(&changes->old_rdata,
+	                                 &changes->old_rdata_types,
+	                                 changes->old_rdata_count,
+	                                 &changes->old_rdata_allocated, 
+	                                 rdata_count);
+	if (ret != KNOT_EOK) {
+		dbg_ddns("Failed to reserve place for RDATA.\n");
+		return ret;
+	}
+
+	/*
+	 * 2) Remove the proper RDATA from the RRSet copy, or its RRSIGs.
+	 */
+	knot_rdata_t *removed = knot_rrset_remove_rdata(to_modify, 
+	                                                knot_rrset_rdata(rr));
+
+	/* No such RR in the RRSet. */
+	if (removed == NULL) {
+		dbg_ddns_detail("No such RR found to be removed.\n");
+		return KNOT_EOK;
+	}
+
+	/* If we removed NS from apex, there should be at least one more. */
+	assert(!is_apex || type != KNOT_RRTYPE_NS 
+	       || knot_rrset_rdata(rrset_copy) != NULL);
+
+	/*
+	 * 3) Store the removed RDATA in 'changes'.
+	 */
+	knot_changes_add_rdata(changes->old_rdata, changes->old_rdata_types,
+	                       &changes->old_rdata_count, removed, type);
+
+	/*
+	 * 4) If the RRSet is empty, remove it and store in 'changes'.
+	 *    Do this also if the RRSIGs are empty. 
+	 *    And if both are empty, remove both.
+	 */
+	if (type == KNOT_RRTYPE_RRSIG 
+	    && knot_rrset_rdata(to_modify) == NULL) {
+		/* Empty RRSIGs, remove the RRSIG RRSet */
+		ret = knot_changes_rrsets_reserve(&changes->old_rrsets,
+		                                 &changes->old_rrsets_count,
+		                                 &changes->old_rrsets_allocated,
+		                                 1);
+		if (ret == KNOT_EOK) {
+			knot_rrset_t *rrsig = knot_rrset_get_rrsigs(rrset_copy);
+			dbg_xfrin_detail("Removed RRSIG RRSet (%p).\n", rrsig);
+			
+			assert(rrsig == to_modify);
+
+			// add the removed RRSet to list of old RRSets
+			changes->old_rrsets[changes->old_rrsets_count++]
+			                = rrsig;
+			
+			// remove it from the RRSet
+			knot_rrset_set_rrsigs(rrset_copy, NULL);
+		} else {
+			dbg_ddns("Failed to reserve space for empty RRSet.\n");
+		}
+	}
+	
+	/*! \note Copied from xfr-in.c - maybe extract to some function. */
+	/*! \note This is not needed as rrset is already on the old_rrsets */
+//	if (knot_rrset_rdata(rrset_copy) == NULL
+//	    && knot_rrset_rrsigs(rrset_copy) == NULL) {
+//		// The RRSet should not be empty if we were removing NSs from
+//		// apex in case of DDNS
+//		assert(!is_apex);
+
+//		ret = knot_changes_rrsets_reserve(&changes->old_rrsets,
+//		                                 &changes->old_rrsets_count,
+//		                                 &changes->old_rrsets_allocated,
+//		                                 1);
+//		if (ret == KNOT_EOK) {
+//			knot_rrset_t *tmp = knot_node_remove_rrset(node, type);
+//			dbg_xfrin_detail("Removed whole RRSet (%p).\n", tmp);
+
+//			assert(tmp == rrset_copy);
+
+//			// add the removed RRSet to list of old RRSets
+//			changes->old_rrsets[changes->old_rrsets_count++]
+//			                = rrset_copy;
+//		} else {
+//			dbg_ddns("Failed to reserve space for empty RRSet.\n");
+//		}
+//	}
+
+	/*
+	 * 5) Check if the RR is not in the ADD section. If yes, remove it
+	 *    from there and do not add it to the REMOVE section.
+	 */
+	knot_rrset_t **from_chgset = NULL;
+	size_t from_chgset_count = 0;
+	ret = knot_ddns_check_remove_rr2(changeset, knot_node_owner(node),
+	                                 type, knot_rrset_rdata(rr),
+	                                 &from_chgset, &from_chgset_count);
+	if (ret != KNOT_EOK) {
+		dbg_ddns("Failed to remove possible redundant RRs from ADD "
+		         "section: %s.\n", knot_strerror(ret));
+		free(from_chgset);
+		return ret;
+	}
+
+	assert(from_chgset_count <= 1);
+
+	if (from_chgset_count == 1) {
+		/* Just delete the RRSet. */
+		knot_rrset_deep_free(&(from_chgset[0]), 1, 1, 1);
+
+		/* Finish processing, no adding to changeset. */
+		free(from_chgset);
+		return KNOT_EOK;
+	}
+	
+	free(from_chgset);
+
+	/*
+	 * 6) Store the RRSet containing the one RDATA in the changeset. We may
+	 *    use the RRSet from the packet for this - copy it, set CLASS
+	 *    and TTL.
+	 */
+	knot_rrset_t *to_chgset = NULL;
+	ret = knot_rrset_deep_copy(rr, &to_chgset, 1);
+	if (ret != KNOT_EOK) {
+		dbg_ddns("Failed to copy RRSet from packet to changeset.\n");
+		return ret;
+	}
+	knot_rrset_set_class(to_chgset, qclass);
+	knot_rrset_set_ttl(to_chgset, knot_rrset_ttl(to_modify));
+
+	ret = knot_changeset_add_rrset(&changeset->remove,
+	                               &changeset->remove_count,
+	                               &changeset->remove_allocated,
+	                               to_chgset);
+	if (ret != KNOT_EOK) {
+		dbg_ddns("Failed to store the RRSet copy to changeset: %s.\n",
+		         knot_strerror(ret));
+		knot_rrset_deep_free(&to_chgset, 1, 1, 1);
+		return ret;
+	}
+
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
+static int knot_ddns_process_rem_rrsig(knot_node_t *node,
+                                       knot_rrset_t *rrset,
+                                       knot_changes_t *changes,
+                                       knot_rrset_t **rrsig)
+{
+	assert(node != NULL);
+	assert(rrset != NULL);
+	assert(changes != NULL);
+	
+	knot_rrset_t *rrset_copy = NULL;
+	
+	/* Copy RRSet. */
+	int ret = xfrin_copy_old_rrset(rrset, &rrset_copy, changes, 1);
+	if (ret != KNOT_EOK) {
+		dbg_ddns("Failed to copy RRSet from node: %s.\n",
+		         knot_strerror(ret));
+		return ret;
+	}
+	
+	/* Remove RRSIGs from the copy. */
+	*rrsig = knot_rrset_get_rrsigs(rrset_copy);
+	if (*rrsig != NULL) {
+		knot_rrset_set_rrsigs(rrset_copy, NULL);
+	}
+	
+	/* Put the copy to the node. */
+	ret = knot_node_add_rrset(node, rrset_copy, 0);
+	if (ret != KNOT_EOK) {
+		dbg_ddns("Failed to add RRSet copy to the node: %s\n",
+		         knot_strerror(ret));
+		knot_rrset_deep_free(&rrset_copy, 1, 1, 1);
+		return ret;
+	}
+	
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
+static int knot_ddns_process_rem_rrsigs(knot_node_t *node, 
+                                        knot_changes_t *changes, 
+                                        knot_rrset_t ***removed,
+                                        size_t *removed_count)
+{
+	assert(node != NULL);
+	assert(removed != NULL);
+	assert(removed_count != NULL);
+	assert(changes != NULL);
+	
+	/* If removing RRSIGs, we must remove them from all RRSets in 
+	 * the node. This means to copy all RRSets and then remove the 
+	 * RRSIGs from them.
+	 */
+	dbg_ddns_verb("Removing all RRSIGs from node.\n");
+	
+	knot_rrset_t **rrsets = knot_node_get_rrsets(node);
+	if (rrsets == NULL) {
+		// No RRSets in the node, nothing to remove
+		return KNOT_EOK;
+	}
+	
+	/* Allocate space for the removed RRSIGs. There may be as many as there
+	 * are RRSets.
+	 */
+	short rrset_count = knot_node_rrset_count(node);
+	
+	*removed = malloc(rrset_count * sizeof(knot_rrset_t *));
+	CHECK_ALLOC_LOG(*removed, KNOT_ENOMEM);
+	*removed_count = 0;
+	
+	/* Remove all the RRSets from the node, so that we may insert the copies
+	 * right away.
+	 */
+	knot_node_remove_all_rrsets(node);
+	
+	knot_rrset_t *rrsig = NULL;
+	int ret = 0;
+	for (int i = 0; i < rrset_count; ++i) {
+		ret = knot_ddns_process_rem_rrsig(node, rrsets[i], changes,
+		                                  &rrsig);
+		if (ret != KNOT_EOK) {
+			dbg_ddns("Failed to remove RRSIG.\n");
+			return ret;
+		}
+		/* Store the RRSIGs to the array of removed RRSets. */
+		(*removed)[(*removed_count)++] = rrsig;
+	}
+	
+	free(rrsets);
+	
+	
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
+static int knot_ddns_process_rem_rrset(uint16_t type,
+                                       knot_node_t *node,
+                                       knot_changeset_t *changeset,
+                                       knot_changes_t *changes)
+{
+	assert(node != NULL);
+	assert(changeset != NULL);
+	assert(changes != NULL);
+
+	/*! \note
+	 * We decided to automatically remove RRSIGs together with the removed
+	 * RRSet as they are no longer valid or required anyway. 
+	 *
+	 * Also refer to RFC3007, section 4.3:
+	 *   'When the contents of an RRset are updated, the server MAY delete 
+	 *    all associated SIG records, since they will no longer be valid.'
+	 *
+	 * (Although we are compliant with this RFC only selectively. The next
+	 * section says: 'If any changes are made, the server MUST, if 
+	 * necessary, generate a new SOA record and new NXT records, and sign 
+	 * these with the appropriate zone keys.' and we are definitely not 
+	 * doing this...
+	 *
+	 * \todo Document!!
+	 */
+
+	// this should be ruled out before
+	assert(type != KNOT_RRTYPE_SOA);
+
+	if (knot_node_rrset(node, KNOT_RRTYPE_SOA) != NULL
+	    && type == KNOT_RRTYPE_NS) {
+		// if removing NS from apex, ignore
+		return KNOT_EOK;
+	}
+	
+	knot_rrset_t **removed = NULL;
+	size_t removed_count = 0;
+	int ret = 0;
+	
+	if (type == KNOT_RRTYPE_RRSIG) {
+		/* Remove all RRSIGs from the node. */
+		ret = knot_ddns_process_rem_rrsigs(node, changes, &removed,
+		                                   &removed_count);
+	} else {
+		/* Remove the RRSet from the node. */
+		removed = malloc(sizeof(knot_rrset_t *));
+		if (!removed) {
+			ERR_ALLOC_FAILED;
+			return KNOT_ENOMEM;
+		}
+
+		dbg_ddns_detail("Removing RRSet of type: %d\n", type);
+		
+		*removed = knot_node_remove_rrset(node, type);
+		removed_count = 1;
+	}
+
+	dbg_ddns_detail("Removed: %p (first item: %p), removed count: %d\n",
+	                removed, (removed == NULL) ? "none" : *removed,
+	                removed_count);
+
+	// no such RR
+	if (removed_count == 0 || removed == NULL) {
+		// ignore
+		return KNOT_EOK;
+	}
+
+	/* 2) Store them to 'changes' for later deallocation, together with
+	 *    their RRSIGs. 
+	 */
+	ret = knot_changes_add_old_rrsets(removed, removed_count, changes, 1);
+	if (ret != KNOT_EOK) {
+		dbg_ddns("Failed to add removed RRSet to 'changes': %s.\n",
+		         knot_strerror(ret));
+		free(removed);
+		return ret;
+	}
+
+	/* 3) Copy the RRSets, so that they can be stored to the changeset. */
+	knot_rrset_t **to_chgset = malloc(removed_count 
+	                                  * sizeof(knot_rrset_t *));
+	if (to_chgset == NULL) {
+		dbg_ddns("Failed to allocate space for RRSets going to "
+		         "changeset.\n");
+		free(removed);
+		return KNOT_ENOMEM;
+	}
+	
+	for (int i = 0; i < removed_count; ++i) {
+		ret = knot_rrset_deep_copy(removed[i], &to_chgset[i], 1);
+		if (ret != KNOT_EOK) {
+			dbg_ddns("Failed to copy the removed RRSet: %s.\n",
+			         knot_strerror(ret));
+			for (int j = 0; j < i; ++j) {
+				knot_rrset_deep_free(&to_chgset[j], 1, 1, 1);
+			}
+			free(to_chgset);
+			free(removed);
+			return ret;
+		}
+	}
+	
+	free(removed);
+
+	/* 4) But we must check if some of the RRs were not previously added
+	 *    by the same UPDATE. If yes, these must be removed from the ADD
+	 *    section of the changeset and also from this RRSet copy (so they
+	 *    are neither stored in the REMOVE section of the changeset).
+	 */
+	knot_rrset_t **from_chgset = NULL;
+	size_t from_chgset_count = 0;
+
+	/* 4 a) Remove redundant RRs from the ADD section of the changeset. */
+	ret = knot_ddns_check_remove_rr2(changeset, knot_node_owner(node), type,
+	                                 NULL, &from_chgset,
+	                                 &from_chgset_count);
+	if (ret != KNOT_EOK) {
+		dbg_ddns("Failed to remove possible redundant RRs from ADD "
+		         "section: %s.\n", knot_strerror(ret));
+		for (int i = 0; i < removed_count; ++i) {
+			knot_rrset_deep_free(&to_chgset[i], 1, 1, 1);
+		}
+		free(from_chgset);
+		free(to_chgset);
+		return ret;
+	}
+
+	/* 4 b) Remove these RRs from the copy of the RRSets removed from zone*/
+	knot_rdata_t *rem = NULL;
+	for (int j = 0; j < removed_count; ++j) {
+		/* In each RRSet removed from the node (each can have more
+		 * RDATAs) ...
+		 */
+		for (int i = 0; i < from_chgset_count; ++i) {
+			/* ...try to remove redundant RDATA. Each RRSet in
+			 * 'from_chgset' contains only one RDATA.
+			 */
+			rem = knot_rrset_remove_rdata(to_chgset[j], 
+			                              knot_rrset_rdata(
+			                                  from_chgset[i]));
+			/* And delete it right away, no use for that. */
+			knot_rdata_deep_free(&rem, knot_rrset_type(
+			                             from_chgset[i]), 1);
+		}
+	}
+	
+	/* The array is cleared, we may delete the redundant RRs. */
+	for (int i = 0; i < from_chgset_count; ++i) {
+		knot_rrset_deep_free(&from_chgset[i], 1, 1, 1);
+	}
+	free(from_chgset);
+
+	/* 5) Store the remaining RRSet to the changeset. Do not try to merge
+	 *    to some previous RRSet, there should be none.
+	 */
+	for (int i = 0; i < removed_count; ++i) {
+		ret = knot_changeset_add_rrset(&changeset->remove,
+		                               &changeset->remove_count,
+		                               &changeset->remove_allocated,
+		                               to_chgset[i]);
+		if (ret != KNOT_EOK) {
+			dbg_ddns("Failed to store the RRSet copy to changeset: "
+			         "%s.\n", knot_strerror(ret));
+			for (int j = i; j < removed_count; ++j) {
+				knot_rrset_deep_free(&to_chgset[j], 1, 1, 1);
+			}
+			free(to_chgset);
+			return ret;
+		}
+	}
+	
+	free(to_chgset);
+
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
+static int knot_ddns_process_rem_all(knot_node_t *node,
+                                     knot_changeset_t *changeset,
+                                     knot_changes_t *changes)
+{
+	assert(node != NULL);
+	assert(changeset != NULL);
+	assert(changes != NULL);
+
+	/*! \note
+	 * This basically means to call knot_ddns_process_rem_rrset() for every
+	 * type present in the node.
+	 *
+	 * In case of SOA and NS in apex, the RRSets should not be removed, but
+	 * what about their RRSIGs??
+	 *
+	 * If the zone has to remain properly signed, the UPDATE will have to 
+	 * contain at least new SOA and RRSIGs for it (as the auto-incremented
+	 * SOA would not be signed). So it should not matter if we leave the 
+	 * RRSIGs there or not. But in case of the NSs it's not that clear.
+	 *
+	 * For now, we will leave the RRSIGs there. It's easier to implement.
+	 * 
+	 * \todo Should document this!!
+	 */
+	int ret = 0;
+	knot_rrset_t **rrsets = knot_node_get_rrsets(node);
+	int count = knot_node_rrset_count(node);
+
+	if (rrsets == NULL && count != 0) {
+		dbg_ddns("Failed to fetch RRSets from node.\n");
+		return KNOT_ENOMEM;
+	}
+
+	int is_apex = knot_node_rrset(node, KNOT_RRTYPE_SOA) != NULL;
+
+	dbg_ddns_verb("Removing all RRSets (count: %d).\n", count);
+	for (int i = 0; i < count; ++i) {
+		// If the node is apex, skip NS and SOA
+		if (is_apex &&
+		    (knot_rrset_type(rrsets[i]) == KNOT_RRTYPE_SOA
+		     || knot_rrset_type(rrsets[i]) == KNOT_RRTYPE_NS)) {
+			/* Do not remove these RRSets, nor their RRSIGs. */
+			continue;
+		}
+
+		ret = knot_ddns_process_rem_rrset(knot_rrset_type(rrsets[i]),
+		                                  node, changeset, changes);
+		if (ret != KNOT_EOK) {
+			dbg_ddns("Failed to remove RRSet: %s\n",
+			         knot_strerror(ret));
+			free(rrsets);
+			return ret;
+		}
+	}
+	
+	free(rrsets);
+
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
+static int knot_ddns_process_rr(const knot_rrset_t *rr,
+                                knot_zone_contents_t *zone,
+                                knot_changeset_t *changeset,
+                                knot_changes_t *changes, uint16_t qclass,
+                                knot_rrset_t **rr_copy)
+{
+	assert(rr != NULL);
+	assert(zone != NULL);
+	assert(changeset != NULL);
+	assert(changes != NULL);
+	assert(rr_copy != NULL);
+
+	/* 1) Find node that will be affected. */
+	knot_node_t *node = knot_ddns_get_node(zone, rr);
+
+	/* 2) Decide what to do. */
+
+	if (knot_rrset_class(rr) == knot_zone_contents_class(zone)) {
+		return knot_ddns_process_add(rr, node, zone, changeset,
+		                             changes, rr_copy);
+	} else if (knot_rrset_class(rr) == KNOT_CLASS_NONE) {
+		return knot_ddns_process_rem_rr(rr, node, zone, changeset,
+		                                changes, qclass);
+	} else if (knot_rrset_class(rr) == KNOT_CLASS_ANY) {
+		if (knot_rrset_type(rr) == KNOT_RRTYPE_ANY) {
+			return knot_ddns_process_rem_all(node, changeset,
+			                                 changes);
+		} else {
+			return knot_ddns_process_rem_rrset(knot_rrset_type(rr),
+			                                   node, changeset, 
+			                                   changes);
+		}
+	} else {
+		assert(0);
+		return KNOT_ERROR;
+	}
+}
+
+/*----------------------------------------------------------------------------*/
+/*
+ * NOTES:
+ * - 'zone' must be a copy of the current zone.
+ * - changeset must be allocated
+ * - changes must be allocated
+ *
+ * All this is done in the first parts of xfrin_apply_changesets() - extract
+ * to separate function, if possible.
+ *
+ * If anything fails, rollback must be done. The xfrin_rollback_update() may
+ * be good for this.
+ */
+int knot_ddns_process_update2(knot_zone_contents_t *zone,
+                              const knot_packet_t *query,
+                              knot_changeset_t *changeset,
+                              knot_changes_t *changes,
+                              knot_rcode_t *rcode)
+{
+	if (zone == NULL || query == NULL || changeset == NULL || rcode == NULL
+	    || changes == NULL) {
+		return KNOT_EINVAL;
+	}
+
+	int ret = KNOT_EOK;
+
+	/* Copy base SOA RR. */
+	const knot_rrset_t *soa = knot_node_rrset(knot_zone_contents_apex(zone),
+						  KNOT_RRTYPE_SOA);
+	knot_rrset_t *soa_begin = NULL;
+	knot_rrset_t *soa_end = NULL;
+	ret = knot_rrset_deep_copy(soa, &soa_begin, 0);
+	if (ret == KNOT_EOK) {
+		knot_changeset_store_soa(&changeset->soa_from,
+		                         &changeset->serial_from, soa_begin);
+	} else {
+		*rcode = KNOT_RCODE_SERVFAIL;
+		return ret;
+	}
+
+	/* Current SERIAL */
+	int64_t sn = knot_rdata_soa_serial(knot_rrset_rdata(soa_begin));
+	int64_t sn_new;
+
+	/* Incremented SERIAL
+	 * We must set it now to be able to compare SERIAL from SOAs in the
+	 * UPDATE to it. Although we do not have the new SOA yet.
+	 */
+	if (sn > -1) {
+		sn_new = (uint32_t)sn + 1;
+	} else {
+		*rcode = KNOT_RCODE_SERVFAIL;
+		return ret;
+	}
+
+	/* Process all RRs the Authority (Update) section. */
+
+	const knot_rrset_t *rr = NULL;
+	knot_rrset_t *rr_copy = NULL;
+
+	dbg_ddns("Processing UPDATE section.\n");
+	for (int i = 0; i < knot_packet_authority_rrset_count(query); ++i) {
+
+		rr = knot_packet_authority_rrset(query, i);
+
+		/* Check if the entry is correct. */
+		ret = knot_ddns_check_update(rr, query, rcode);
+		if (ret != KNOT_EOK) {
+			dbg_ddns("Failed to check update RRSet:%s\n",
+			                knot_strerror(ret));
+			return ret;
+		}
+
+		/* Check if the record is SOA. If yes, check the SERIAL.
+		 * If this record should cause the SOA to be replaced in the
+		 * zone, use it as the ending SOA.
+		 *
+		 * Also handle cases where there are multiple SOAs to be added
+		 * in the same UPDATE. The one with the largest SERIAL should
+		 * be used.
+		 *
+		 * TODO: If there are more SOAs in the UPDATE one after another,
+		 *       the ddns_add_update() function will merge them into a
+		 *       RRSet. This should be handled somehow.
+		 *
+		 * If the serial is not larger than the current zone serial,
+		 * ignore the record and continue. This will ensure that the
+		 * RR processing function receives only SOA RRs that should be
+		 * added to the zone (replacing the old one).
+		 */
+		if (knot_rrset_type(rr) == KNOT_RRTYPE_SOA
+		    && (knot_rrset_class(rr) == KNOT_CLASS_NONE
+		        || knot_rrset_class(rr) == KNOT_CLASS_ANY
+		        || ns_serial_compare(knot_rdata_soa_serial(
+		                        knot_rrset_rdata(rr)), sn_new) < 0)) {
+			// This ignores also SOA removals
+			dbg_ddns_verb("Ignoring SOA...\n");
+			continue;
+		}
+
+		ret = knot_ddns_process_rr(rr, zone, changeset, changes,
+		                           knot_packet_qclass(query),
+		                           &rr_copy);
+
+		if (ret != KNOT_EOK) {
+			dbg_ddns("Failed to process update RR:%s\n",
+			         knot_strerror(ret));
+			*rcode = (ret == KNOT_EMALF) ? KNOT_RCODE_FORMERR
+			                             : KNOT_RCODE_SERVFAIL;
+			return ret;
+		}
+
+		// we need the RR copy, that's why this code is here
+		if (knot_rrset_type(rr) == KNOT_RRTYPE_SOA) {
+			int64_t sn_rr = knot_rdata_soa_serial(
+			                        knot_rrset_rdata(rr));
+			dbg_ddns_verb("Replacing SOA. Old serial: %d, new "
+			              "serial: %d\n", sn_new, sn_rr);
+			assert(ns_serial_compare(sn_rr, sn_new) >= 0);
+			assert(rr_copy != NULL);
+			sn_new = sn_rr;
+			soa_end = (knot_rrset_t *)rr_copy;
+		}
+	}
+
+	/* Ending SOA (not in the UPDATE) */
+	if (soa_end == NULL) {
+		/* If the changeset is empty, do not process anything further 
+		 * and indicate this to the caller, so that the changeset is not
+		 * saved and zone is not switched.
+		 */
+		if (knot_changeset_is_empty(changeset)) {
+			return 1;
+		}
+		
+		/* If not set, create new SOA. */
+		assert(sn_new == (uint32_t)sn + 1);
+		ret = knot_rrset_deep_copy(soa, &soa_end, 1);
+		if (ret != KNOT_EOK) {
+			dbg_ddns("Failed to copy ending SOA: %s\n",
+			         knot_strerror(ret));
+			*rcode = KNOT_RCODE_SERVFAIL;
+			return ret;
+		}
+		knot_rdata_t *rd = knot_rrset_get_rdata(soa_end);
+		knot_rdata_soa_serial_set(rd, sn_new);
+		
+		/* And replace it in the zone. */
+		ret = xfrin_replace_rrset_in_node(
+		                        knot_zone_contents_get_apex(zone),
+		                        soa_end, changes, zone);
+		if (ret != KNOT_EOK) {
+			dbg_ddns("Failed to copy replace SOA in zone: %s\n",
+			         knot_strerror(ret));
+			*rcode = KNOT_RCODE_SERVFAIL;
+			return ret;
+		}
+	}
+
+	ret = knot_ddns_final_soa_to_chgset(soa_end, changeset);
+
+	return ret;
+}
diff --git a/src/libknot/updates/ddns.h b/src/libknot/updates/ddns.h
index 35dfcb7..d3cb359 100644
--- a/src/libknot/updates/ddns.h
+++ b/src/libknot/updates/ddns.h
@@ -32,6 +32,8 @@
 #include "packet/packet.h"
 #include "rrset.h"
 #include "dname.h"
+#include "consts.h"
+#include "common/lists.h"
 
 typedef struct knot_ddns_prereq_t {
 	knot_rrset_t **exist;
@@ -55,17 +57,24 @@ typedef struct knot_ddns_prereq_t {
 	size_t not_in_use_allocd;
 } knot_ddns_prereq_t;
 
-int knot_ddns_check_zone(const knot_zone_t *zone, knot_packet_t *query,
-                         uint8_t *rcode);
+int knot_ddns_check_zone(const knot_zone_contents_t *zone, 
+                         const knot_packet_t *query, knot_rcode_t *rcode);
 
-int knot_ddns_process_prereqs(knot_packet_t *query,
-                              knot_ddns_prereq_t **prereqs, uint8_t *rcode);
+int knot_ddns_process_prereqs(const knot_packet_t *query,
+                              knot_ddns_prereq_t **prereqs, knot_rcode_t *rcode);
 
 int knot_ddns_check_prereqs(const knot_zone_contents_t *zone,
-                            knot_ddns_prereq_t **prereqs, uint8_t *rcode);
+                            knot_ddns_prereq_t **prereqs, knot_rcode_t *rcode);
 
-int knot_ddns_process_update(knot_packet_t *query,
-                             knot_changeset_t **changeset, uint8_t *rcode);
+int knot_ddns_process_update(const knot_zone_contents_t *zone,
+			     const knot_packet_t *query,
+                             knot_changeset_t *changeset, knot_rcode_t *rcode);
+
+int knot_ddns_process_update2(knot_zone_contents_t *zone,
+                              const knot_packet_t *query,
+                              knot_changeset_t *changeset,
+                              knot_changes_t *changes,
+                              knot_rcode_t *rcode);
 
 void knot_ddns_prereqs_free(knot_ddns_prereq_t **prereq);
 
diff --git a/src/libknot/updates/xfr-in.c b/src/libknot/updates/xfr-in.c
index 7d3ffdf..98d4df6 100644
--- a/src/libknot/updates/xfr-in.c
+++ b/src/libknot/updates/xfr-in.c
@@ -267,14 +267,14 @@ static int xfrin_add_orphan_rrsig(xfrin_orphan_rrsig_t **rrsigs,
 	while (last != NULL) {
 		// check if the RRSIG is not similar to the one we want to add
 		assert(last->rrsig != NULL);
-		if (knot_rrset_compare(last->rrsig, rr, 
+		if (knot_rrset_match(last->rrsig, rr, 
 		                       KNOT_RRSET_COMPARE_HEADER) == 1
 		    && knot_rdata_rrsig_type_covered(knot_rrset_rdata(
 		                                     last->rrsig))
 		       == knot_rdata_rrsig_type_covered(knot_rrset_rdata(rr))) {
 			ret = knot_rrset_merge_no_dupl((void **)&last->rrsig,
 			                               (void **)&rr);
-			if (ret != KNOT_EOK) {
+			if (ret < 0) {
 				return ret;
 			} else {
 				return 1;
@@ -955,13 +955,13 @@ int xfrin_process_ixfr_packet(knot_ns_xfr_t *xfr)
 	if (*chs == NULL) {
 		dbg_xfrin_verb("Changesets empty, creating new.\n");
 		
-		ret = knot_changeset_allocate(chs);
+		ret = knot_changeset_allocate(chs, KNOT_CHANGESET_TYPE_IXFR);
 		if (ret != KNOT_EOK) {
 			knot_rrset_deep_free(&rr, 1, 1, 1);
 			knot_packet_free(&packet);
 			return ret;
 		}
-		
+
 		// the first RR must be a SOA
 		if (knot_rrset_type(rr) != KNOT_RRTYPE_SOA) {
 			dbg_xfrin("First RR is not a SOA RR!\n");
@@ -1069,9 +1069,9 @@ int xfrin_process_ixfr_packet(knot_ns_xfr_t *xfr)
 		assert((*chs)->sets[(*chs)->count - 1].soa_from != NULL);
 		
 		if ((*chs)->sets[(*chs)->count - 1].soa_to == NULL) {
-			state = XFRIN_CHANGESET_REMOVE;
+			state = KNOT_CHANGESET_REMOVE;
 		} else {
-			state = XFRIN_CHANGESET_ADD;
+			state = KNOT_CHANGESET_ADD;
 		}
 	}
 	
@@ -1134,17 +1134,17 @@ dbg_xfrin_exec_verb(
 						
 				ret = knot_changeset_add_soa(
 					&(*chs)->sets[(*chs)->count - 1], rr, 
-					XFRIN_CHANGESET_REMOVE);
+					KNOT_CHANGESET_REMOVE);
 				if (ret != KNOT_EOK) {
 					knot_rrset_deep_free(&rr, 1, 1, 1);
 					goto cleanup;
 				}
 				
 				// change state to REMOVE
-				state = XFRIN_CHANGESET_REMOVE;
+				state = KNOT_CHANGESET_REMOVE;
 			}
 			break;
-		case XFRIN_CHANGESET_REMOVE:
+		case KNOT_CHANGESET_REMOVE:
 			// if the next RR is SOA, store it and change state to
 			// ADD
 			if (knot_rrset_type(rr) == KNOT_RRTYPE_SOA) {
@@ -1154,25 +1154,25 @@ dbg_xfrin_exec_verb(
 				
 				ret = knot_changeset_add_soa(
 					&(*chs)->sets[(*chs)->count - 1], rr, 
-					XFRIN_CHANGESET_ADD);
+					KNOT_CHANGESET_ADD);
 				if (ret != KNOT_EOK) {
 					knot_rrset_deep_free(&rr, 1, 1, 1);
 					goto cleanup;
 				}
 				
-				state = XFRIN_CHANGESET_ADD;
+				state = KNOT_CHANGESET_ADD;
 			} else {
 				// just add the RR to the REMOVE part and
 				// continue
 				if ((ret = knot_changeset_add_new_rr(
 				         &(*chs)->sets[(*chs)->count - 1], rr,
-				         XFRIN_CHANGESET_REMOVE)) != KNOT_EOK) {
+				         KNOT_CHANGESET_REMOVE)) != KNOT_EOK) {
 					knot_rrset_deep_free(&rr, 1, 1, 1);
 					goto cleanup;
 				}
 			}
 			break;
-		case XFRIN_CHANGESET_ADD:
+		case KNOT_CHANGESET_ADD:
 			// if the next RR is SOA change to state -1 and do not
 			// parse next RR
 			if (knot_rrset_type(rr) == KNOT_RRTYPE_SOA) {
@@ -1183,7 +1183,7 @@ dbg_xfrin_exec_verb(
 				// just add the RR to the ADD part and continue
 				if ((ret = knot_changeset_add_new_rr(
 				            &(*chs)->sets[(*chs)->count - 1], rr,
-				            XFRIN_CHANGESET_ADD)) != KNOT_EOK) {
+				            KNOT_CHANGESET_ADD)) != KNOT_EOK) {
 					knot_rrset_deep_free(&rr, 1, 1, 1);
 					goto cleanup;
 				}
@@ -1230,137 +1230,6 @@ cleanup:
 /* Applying changesets to zone                                                */
 /*----------------------------------------------------------------------------*/
 
-static int xfrin_changes_check_rrsets(knot_rrset_t ***rrsets,
-                                      int *count, int *allocated, int to_add)
-{
-	if (*count + to_add <= *allocated) {
-		return KNOT_EOK;
-	}
-
-	int new_count = (*allocated == 0) ? 2 : *allocated * 2;
-	while (new_count < *count + to_add) {
-		new_count *= 2;
-	}
-
-	/* Allocate new memory block. */
-	knot_rrset_t **rrsets_new = malloc(new_count * sizeof(knot_rrset_t *));
-	if (rrsets_new == NULL) {
-		return KNOT_ENOMEM;
-	}
-
-	/* Initialize new memory and copy old data. */
-	memset(rrsets_new, 0, new_count * sizeof(knot_rrset_t *));
-	memcpy(rrsets_new, *rrsets, (*allocated) * sizeof(knot_rrset_t *));
-
-	/* Free old nodes and switch pointers. */
-	free(*rrsets);
-	*rrsets = rrsets_new;
-	*allocated = new_count;
-
-	return KNOT_EOK;
-}
-
-/*----------------------------------------------------------------------------*/
-
-static int xfrin_changes_check_nodes(knot_node_t ***nodes,
-                                     int *count, int *allocated)
-{
-	assert(nodes != NULL);
-	assert(count != NULL);
-	assert(allocated != 0);
-
-	if (*count + 2 <= *allocated) {
-		return KNOT_EOK;
-	}
-
-	int new_count = (*allocated == 0) ? 2 : *allocated * 2;
-
-	/* Allocate new memory block. */
-	const size_t node_len = sizeof(knot_node_t *);
-	knot_node_t **nodes_new = malloc(new_count * node_len);
-	if (nodes_new == NULL) {
-		return KNOT_ENOMEM;
-	}
-
-	/* Clear memory block and copy old data. */
-	memset(nodes_new, 0, new_count * node_len);
-	memcpy(nodes_new, *nodes, (*allocated) * node_len);
-
-	/* Free old nodes and switch pointers. */
-	free(*nodes);
-	*nodes = nodes_new;
-	*allocated = new_count;
-
-	return KNOT_EOK;
-}
-
-/*----------------------------------------------------------------------------*/
-
-static int xfrin_changes_check_rdata(knot_rdata_t ***rdatas, uint **types,
-                                     int count, int *allocated, int to_add)
-{
-	if (count + to_add <= *allocated) {
-		return KNOT_EOK;
-	}
-
-	int new_count = (*allocated == 0) ? 2 : *allocated * 2;
-	while (new_count < count + to_add) {
-		new_count *= 2;
-	}
-
-	/* Allocate new memory block. */
-	knot_rdata_t **rdatas_new = malloc(new_count * sizeof(knot_rdata_t *));
-	if (rdatas_new == NULL) {
-		return KNOT_ENOMEM;
-	}
-
-	uint *types_new = malloc(new_count * sizeof(uint));
-	if (types_new == NULL) {
-		free(rdatas_new);
-		return KNOT_ENOMEM;
-	}
-
-	/* Initialize new memory and copy old data. */
-	memset(rdatas_new, 0, new_count * sizeof(knot_rdata_t *));
-	memcpy(rdatas_new, *rdatas, (*allocated) * sizeof(knot_rdata_t *));
-
-	memset(types_new, 0, new_count * sizeof(uint));
-	memcpy(types_new, *types, (*allocated) * sizeof(uint));
-
-	/* Free old rdatas and switch pointers. */
-	free(*rdatas);
-	free(*types);
-	*rdatas = rdatas_new;
-	*types = types_new;
-	*allocated = new_count;
-
-	return KNOT_EOK;
-}
-
-/*----------------------------------------------------------------------------*/
-
-static void xfrin_changes_add_rdata(knot_rdata_t **rdatas, uint *types,
-                                    int *count, knot_rdata_t *rdata, uint type)
-{
-	if (rdata == NULL) {
-		return;
-	}
-
-	// Add all RDATAs from the chain!!
-
-	knot_rdata_t *r = rdata;
-	do {
-		dbg_xfrin_detail("Adding RDATA to RDATA list: %p\n", r);
-		rdatas[*count] = r;
-		types[*count] = type;
-		++*count;
-
-		r = r->next;
-	} while (r != NULL && r != rdata);
-}
-
-/*----------------------------------------------------------------------------*/
-
 static void xfrin_zone_contents_free(knot_zone_contents_t **contents)
 {
 	/*! \todo This should be all in some API!! */
@@ -1386,7 +1255,8 @@ static void xfrin_zone_contents_free(knot_zone_contents_t **contents)
 /*----------------------------------------------------------------------------*/
 
 static knot_rdata_t *xfrin_remove_rdata(knot_rrset_t *from,
-                                        const knot_rrset_t *what)
+                                        const knot_rrset_t *what,
+                                        int ddns_check)
 {
 	knot_rdata_t *old = NULL;
 	knot_rdata_t *old_actual = NULL;
@@ -1396,6 +1266,20 @@ static knot_rdata_t *xfrin_remove_rdata(knot_rrset_t *from,
 	while (rdata != NULL) {
 		// rdata - the RDATA to be removed
 		// old_actual - removed RDATA
+
+		/*
+		 * DDNS special handling - last apex NS should remain in the
+		 * zone.
+		 *
+		 * TODO: this is not correct, the last NS from the 'what' RRSet
+		 * may not even be in the zone.
+		 */
+		if (ddns_check
+		    && knot_rrset_rdata_next(what, rdata) == NULL) {
+			assert(knot_rrset_type(from) == KNOT_RRTYPE_NS);
+			return old;
+		}
+
 		old_actual = knot_rrset_remove_rdata(from, rdata);
 		if (old_actual != NULL) {
 			old_actual->next = old;
@@ -1410,8 +1294,8 @@ static knot_rdata_t *xfrin_remove_rdata(knot_rrset_t *from,
 
 /*----------------------------------------------------------------------------*/
 
-static int xfrin_copy_old_rrset(knot_rrset_t *old, knot_rrset_t **copy,
-                                knot_changes_t *changes)
+int xfrin_copy_old_rrset(knot_rrset_t *old, knot_rrset_t **copy,
+                         knot_changes_t *changes, int save_new)
 {
 	dbg_xfrin_detail("Copying old RRSet: %p\n", old);
 	// create new RRSet by copying the old one
@@ -1420,57 +1304,65 @@ static int xfrin_copy_old_rrset(knot_rrset_t *old, knot_rrset_t **copy,
 		dbg_xfrin("Failed to create RRSet copy.\n");
 		return KNOT_ENOMEM;
 	}
+	
+	int count = 0;
 
 	// add the RRSet to the list of new RRSets
 	// create place also for RRSIGs
-	ret = xfrin_changes_check_rrsets(&changes->new_rrsets,
-	                                 &changes->new_rrsets_count,
-	                                 &changes->new_rrsets_allocated, 2);
-	if (ret != KNOT_EOK) {
-		dbg_xfrin("Failed to add new RRSet to list.\n");
-		knot_rrset_deep_free(copy, 1, 1, 1);
-		return ret;
-	}
-
-	int count = knot_rrset_rdata_rr_count(*copy);
-	count += knot_rrset_rdata_rr_count((*copy)->rrsigs);
-
-	// add the copied RDATA to the list of new RDATA
-	ret = xfrin_changes_check_rdata(&changes->new_rdata,
-	                                &changes->new_rdata_types,
-	                                changes->new_rdata_count,
-	                                &changes->new_rdata_allocated, count);
-	if (ret != KNOT_EOK) {
-		dbg_xfrin("Failed to add new RRSet to list.\n");
-		knot_rrset_deep_free(copy, 1, 1, 1);
-		return ret;
-	}
-
-	changes->new_rrsets[changes->new_rrsets_count++] = *copy;
+	if (save_new) {
+		ret = knot_changes_rrsets_reserve(&changes->new_rrsets,
+						  &changes->new_rrsets_count,
+						  &changes->new_rrsets_allocated,
+		                                  2);
+		if (ret != KNOT_EOK) {
+			dbg_xfrin("Failed to add new RRSet to list.\n");
+			knot_rrset_deep_free(copy, 1, 1, 1);
+			return ret;
+		}
 
-	dbg_xfrin_detail("Adding RDATA from the RRSet copy to new RDATA list."
-	                 "\n");
-	xfrin_changes_add_rdata(changes->new_rdata, changes->new_rdata_types,
-	                        &changes->new_rdata_count,
-	                        knot_rrset_get_rdata(*copy),
-	                        knot_rrset_type(*copy));
+		count = knot_rrset_rdata_rr_count(*copy);
+		count += knot_rrset_rdata_rr_count((*copy)->rrsigs);
+	
+		// add the copied RDATA to the list of new RDATA
+		ret = knot_changes_rdata_reserve(&changes->new_rdata,
+						 &changes->new_rdata_types,
+						 changes->new_rdata_count,
+						 &changes->new_rdata_allocated, 
+		                                 count);
+		if (ret != KNOT_EOK) {
+			dbg_xfrin("Failed to add new RRSet to list.\n");
+			knot_rrset_deep_free(copy, 1, 1, 1);
+			return ret;
+		}
+	
+		changes->new_rrsets[changes->new_rrsets_count++] = *copy;
+	
+		dbg_xfrin_detail("Adding RDATA from the RRSet copy to new RDATA list."
+				 "\n");
+		knot_changes_add_rdata(changes->new_rdata, 
+		                       changes->new_rdata_types,
+					&changes->new_rdata_count,
+					knot_rrset_get_rdata(*copy),
+					knot_rrset_type(*copy));
 
-	if ((*copy)->rrsigs != NULL) {
-		assert(old->rrsigs != NULL);
-		changes->new_rrsets[changes->new_rrsets_count++] =
-		                (*copy)->rrsigs;
-
-		dbg_xfrin_detail("Adding RDATA from RRSIG of the RRSet copy to "
-		                 "new RDATA list.\n");
-		xfrin_changes_add_rdata(changes->new_rdata,
-		                        changes->new_rdata_types,
-		                        &changes->new_rdata_count,
-		                        knot_rrset_get_rdata((*copy)->rrsigs),
-		                        KNOT_RRTYPE_RRSIG);
+		if ((*copy)->rrsigs != NULL) {
+			assert(old->rrsigs != NULL);
+			changes->new_rrsets[changes->new_rrsets_count++] =
+					(*copy)->rrsigs;
+	
+			dbg_xfrin_detail("Adding RDATA from RRSIG of the RRSet copy to "
+					 "new RDATA list.\n");
+			knot_changes_add_rdata(changes->new_rdata,
+						changes->new_rdata_types,
+						&changes->new_rdata_count,
+						knot_rrset_get_rdata(
+			                               (*copy)->rrsigs),
+						KNOT_RRTYPE_RRSIG);
+		}
 	}
 
 	// add the old RRSet to the list of old RRSets
-	ret = xfrin_changes_check_rrsets(&changes->old_rrsets,
+	ret = knot_changes_rrsets_reserve(&changes->old_rrsets,
 	                                 &changes->old_rrsets_count,
 	                                 &changes->old_rrsets_allocated, 2);
 	if (ret != KNOT_EOK) {
@@ -1482,7 +1374,7 @@ static int xfrin_copy_old_rrset(knot_rrset_t *old, knot_rrset_t **copy,
 	count += knot_rrset_rdata_rr_count(old->rrsigs);
 
 	// and old RDATA to the list of old RDATA
-	ret = xfrin_changes_check_rdata(&changes->old_rdata,
+	ret = knot_changes_rdata_reserve(&changes->old_rdata,
 	                                &changes->old_rdata_types,
 	                                changes->old_rdata_count,
 	                                &changes->old_rdata_allocated, count);
@@ -1494,7 +1386,7 @@ static int xfrin_copy_old_rrset(knot_rrset_t *old, knot_rrset_t **copy,
 	changes->old_rrsets[changes->old_rrsets_count++] = old;
 
 	dbg_xfrin_detail("Adding RDATA from old RRSet to old RDATA list.\n");
-	xfrin_changes_add_rdata(changes->old_rdata, changes->old_rdata_types,
+	knot_changes_add_rdata(changes->old_rdata, changes->old_rdata_types,
 	                        &changes->old_rdata_count, old->rdata,
 	                        knot_rrset_type(old));
 
@@ -1504,7 +1396,7 @@ static int xfrin_copy_old_rrset(knot_rrset_t *old, knot_rrset_t **copy,
 
 		dbg_xfrin_detail("Adding RDATA from RRSIG of the old RRSet to "
 		                 "old RDATA list.\n");
-		xfrin_changes_add_rdata(changes->old_rdata,
+		knot_changes_add_rdata(changes->old_rdata,
 		                        changes->old_rdata_types,
 		                        &changes->old_rdata_count,
 		                        old->rrsigs->rdata,
@@ -1516,8 +1408,9 @@ static int xfrin_copy_old_rrset(knot_rrset_t *old, knot_rrset_t **copy,
 
 /*----------------------------------------------------------------------------*/
 
-static int xfrin_copy_rrset(knot_node_t *node, knot_rr_type_t type,
-                            knot_rrset_t **rrset, knot_changes_t *changes)
+int xfrin_copy_rrset(knot_node_t *node, knot_rr_type_t type,
+                     knot_rrset_t **rrset, knot_changes_t *changes,
+                     int save_new)
 {
 dbg_xfrin_exec_detail(
 	char *name = knot_dname_to_str(knot_node_owner(node));
@@ -1536,7 +1429,7 @@ dbg_xfrin_exec_detail(
 		return 1;
 	}
 
-	int ret = xfrin_copy_old_rrset(old, rrset, changes);
+	int ret = xfrin_copy_old_rrset(old, rrset, changes, save_new);
 	if (ret != KNOT_EOK) {
 		return ret;
 	}
@@ -1591,7 +1484,7 @@ static int xfrin_apply_remove_rrsigs(knot_changes_t *changes,
 		
 		// copy the rrset
 		dbg_xfrin_detail("Copying RRSet that carries the RRSIGs.\n");
-		ret = xfrin_copy_rrset(node, type, rrset, changes);
+		ret = xfrin_copy_rrset(node, type, rrset, changes, 1);
 		if (ret != KNOT_EOK) {
 			dbg_xfrin("Failed to copy rrset from changeset.\n");
 			return ret;
@@ -1616,7 +1509,7 @@ static int xfrin_apply_remove_rrsigs(knot_changes_t *changes,
 			dbg_xfrin_verb("Using RRSIG from previous iteration\n");
 			rrsigs = *rrsigs_old;
 		} else {
-			ret = xfrin_copy_old_rrset(old, &rrsigs, changes);
+			ret = xfrin_copy_old_rrset(old, &rrsigs, changes, 1);
 			if (ret != KNOT_EOK) {
 				return ret;
 			}
@@ -1640,7 +1533,7 @@ static int xfrin_apply_remove_rrsigs(knot_changes_t *changes,
 	// now in '*rrset' we have a copy of the RRSet which holds the RRSIGs 
 	// and in 'rrsigs' we have the copy of the RRSIGs
 	
-	knot_rdata_t *rdata = xfrin_remove_rdata(rrsigs, remove);
+	knot_rdata_t *rdata = xfrin_remove_rdata(rrsigs, remove, 0);
 	if (rdata == NULL) {
 		dbg_xfrin("Failed to remove RDATA from RRSet: %s.\n",
 		          knot_strerror(ret));
@@ -1650,7 +1543,7 @@ static int xfrin_apply_remove_rrsigs(knot_changes_t *changes,
 
 	int count = knot_rdata_count(rdata);
 	// connect the RDATA to the list of old RDATA
-	ret = xfrin_changes_check_rdata(&changes->old_rdata,
+	ret = knot_changes_rdata_reserve(&changes->old_rdata,
 	                                &changes->old_rdata_types,
 	                                changes->old_rdata_count,
 	                                &changes->old_rdata_allocated, count);
@@ -1658,7 +1551,7 @@ static int xfrin_apply_remove_rrsigs(knot_changes_t *changes,
 		return ret;
 	}
 
-	xfrin_changes_add_rdata(changes->old_rdata, changes->old_rdata_types,
+	knot_changes_add_rdata(changes->old_rdata, changes->old_rdata_types,
 	                        &changes->old_rdata_count, rdata,
 	                        knot_rrset_type(remove));
 	
@@ -1670,7 +1563,7 @@ static int xfrin_apply_remove_rrsigs(knot_changes_t *changes,
 		knot_rrset_set_rrsigs(*rrset, NULL);
 		
 		// add RRSet to the list of old RRSets
-		ret = xfrin_changes_check_rrsets(&changes->old_rrsets,
+		ret = knot_changes_rrsets_reserve(&changes->old_rrsets,
 		                                 &changes->old_rrsets_count,
 		                                 &changes->old_rrsets_allocated,
 		                                 1);
@@ -1695,7 +1588,7 @@ static int xfrin_apply_remove_rrsigs(knot_changes_t *changes,
 			                             knot_rrset_type(*rrset));
 			assert(tmp == *rrset);
 			
-			ret = xfrin_changes_check_rrsets(&changes->old_rrsets,
+			ret = knot_changes_rrsets_reserve(&changes->old_rrsets,
 			                        &changes->old_rrsets_count,
 			                        &changes->old_rrsets_allocated,
 			                        1);
@@ -1720,7 +1613,8 @@ static int xfrin_apply_remove_rrsigs(knot_changes_t *changes,
 static int xfrin_apply_remove_normal(knot_changes_t *changes,
                                      const knot_rrset_t *remove,
                                      knot_node_t *node,
-                                     knot_rrset_t **rrset)
+                                     knot_rrset_t **rrset,
+                                     uint32_t chflags)
 {
 	assert(changes != NULL);
 	assert(remove != NULL);
@@ -1731,7 +1625,18 @@ static int xfrin_apply_remove_normal(knot_changes_t *changes,
 	
 	dbg_xfrin_detail("Removing RRSet: \n");
 	knot_rrset_dump(remove, 0);
-	
+
+	int is_apex = knot_node_rrset(node, KNOT_RRTYPE_SOA) != NULL;
+
+	/*
+	 * First handle the special case of DDNS - do not remove SOA from apex.
+	 */
+	if ((chflags & KNOT_CHANGESET_TYPE_DDNS) && is_apex
+	    && knot_rrset_type(remove) == KNOT_RRTYPE_SOA) {
+		dbg_xfrin_verb("Ignoring SOA removal in UPDATE.\n");
+		return KNOT_EOK;
+	}
+
 	// now we have the copy of the node, so lets get the right RRSet
 	// check if we do not already have it
 	if (*rrset
@@ -1748,7 +1653,7 @@ static int xfrin_apply_remove_normal(knot_changes_t *changes,
 		 *       probably not cause problems. TEST!!
 		 */
 		ret = xfrin_copy_rrset(node,
-			knot_rrset_type(remove), rrset, changes);
+			knot_rrset_type(remove), rrset, changes, 1);
 		if (ret != KNOT_EOK) {
 			return ret;
 		}
@@ -1769,8 +1674,12 @@ dbg_xfrin_exec_detail(
 );
 
 	// remove the specified RRs from the RRSet (de facto difference of sets)
-	knot_rdata_t *rdata = xfrin_remove_rdata(*rrset, remove);
-	if (rdata == NULL) {
+	int ddns_remove_ns_from_apex =
+	                ((chflags & KNOT_CHANGESET_TYPE_DDNS) && is_apex
+	                 && knot_rrset_type(*rrset) == KNOT_RRTYPE_NS);
+	knot_rdata_t *rdata = xfrin_remove_rdata(*rrset, remove,
+	                                         ddns_remove_ns_from_apex);
+	if (rdata == NULL && !ddns_remove_ns_from_apex) {
 		dbg_xfrin_verb("Failed to remove RDATA from RRSet\n");
 		// In this case, the RDATA was not found in the RRSet
 		return 1;
@@ -1788,25 +1697,32 @@ dbg_xfrin_exec_detail(
 	}
 );
 
-	int count = knot_rdata_count(rdata);
-	// connect the RDATA to the list of old RDATA
-	ret = xfrin_changes_check_rdata(&changes->old_rdata,
-	                                &changes->old_rdata_types,
-	                                changes->old_rdata_count,
-	                                &changes->old_rdata_allocated, count);
-	if (ret != KNOT_EOK) {
-		return ret;
-	}
+	if (rdata != NULL) {
+		int count = knot_rdata_count(rdata);
+		// connect the RDATA to the list of old RDATA
+		ret = knot_changes_rdata_reserve(&changes->old_rdata,
+		                                &changes->old_rdata_types,
+		                                changes->old_rdata_count,
+		                                &changes->old_rdata_allocated,
+		                                count);
+		if (ret != KNOT_EOK) {
+			return ret;
+		}
 
-	xfrin_changes_add_rdata(changes->old_rdata, changes->old_rdata_types,
-	                        &changes->old_rdata_count, rdata,
-	                        knot_rrset_type(remove));
+		knot_changes_add_rdata(changes->old_rdata,
+		                        changes->old_rdata_types,
+		                        &changes->old_rdata_count, rdata,
+		                        knot_rrset_type(remove));
+	}
 	
 	// if the RRSet is empty, remove from node and add to old RRSets
 	// check if there is no RRSIGs; if there are, leave the RRSet
 	// there; it may be eventually removed when the RRSIGs are removed
 	if (knot_rrset_rdata(*rrset) == NULL
 	    && knot_rrset_rrsigs(*rrset) == NULL) {
+		// The RRSet should not be empty if we were removing NSs from
+		// apex in case of DDNS
+		assert(!ddns_remove_ns_from_apex);
 		
 		knot_rrset_t *tmp = knot_node_remove_rrset(node,
 		                                     knot_rrset_type(*rrset));
@@ -1815,7 +1731,7 @@ dbg_xfrin_exec_detail(
 		// add the removed RRSet to list of old RRSets
 		
 		assert(tmp == *rrset);
-		ret = xfrin_changes_check_rrsets(&changes->old_rrsets,
+		ret = knot_changes_rrsets_reserve(&changes->old_rrsets,
 		                                 &changes->old_rrsets_count,
 		                                 &changes->old_rrsets_allocated,
 		                                 1);
@@ -1836,43 +1752,124 @@ dbg_xfrin_exec_detail(
 /*----------------------------------------------------------------------------*/
 /*! \todo Needs review - RRs may not be merged into RRSets. */
 static int xfrin_apply_remove_all_rrsets(knot_changes_t *changes,
-                                         knot_node_t *node, uint16_t type)
+                                         knot_node_t *node, uint16_t type,
+                                         uint32_t chflags)
 {
-	int ret;
+	int ret = KNOT_EOK;
+	knot_rrset_t **rrsets = NULL;
+	unsigned rrsets_count = 0;
+	int is_apex = knot_node_rrset(node, KNOT_RRTYPE_SOA) != NULL;
 
-	if (type == KNOT_RRTYPE_ANY) {
-		// put all the RRSets to the changes structure
-		ret = xfrin_changes_check_rrsets(&changes->old_rrsets,
-		                                 &changes->old_rrsets_count,
-		                                 &changes->old_rrsets_allocated,
-		                                 knot_node_rrset_count(node));
-		if (ret != KNOT_EOK) {
-			dbg_xfrin("Failed to check changeset rrsets.\n");
-			return ret;
-		}
+dbg_xfrin_exec_verb(
+	char *name = knot_dname_to_str(knot_node_owner(node));
+	dbg_xfrin_verb("Removing all RRSets from node %s of type %s. "
+		       "Is apex: %d, changeset flags: %u\n",
+		       name, knot_rrtype_to_string(type), is_apex, chflags);
+	free(name);
+);
 
-		knot_rrset_t **rrsets = knot_node_get_rrsets(node);
-		knot_rrset_t **place = changes->old_rrsets
-		                       + changes->old_rrsets_count;
-		/*! \todo Test this!!! */
-		memcpy(place, rrsets, knot_node_rrset_count(node)
-		       * sizeof(knot_rrset_t *));
+	/*! \todo ref #937 is it OK to modify nodes at this point?
+	 * shouldn't it be after the zones are switched? */
+	
+	/* Assemble RRSets to remove. */
+	if (type == KNOT_RRTYPE_ANY) {
+		/* Remove all RRSets from the node. */
+		/* If removing from zone apex in an UPDATE, NS and SOA records
+		 * should be left unchanged.
+		 * We might either remove all RRSets and then return SOA and
+		 * NS RRSets to the node. Or find all existing types in the node
+		 * and remove all except NS and SOA. The first approach is
+		 * IMHO faster.
+		 */
 
-		// remove all RRSets from the node
+		rrsets = knot_node_get_rrsets(node);
+		short rr_count = knot_node_rrset_count(node);
+		if (rr_count > 0) {
+			rrsets_count = (unsigned)rr_count;
+		}
 		knot_node_remove_all_rrsets(node);
+
+		/*
+		 * If apex, return SOA and NS RRSets to the node and remove
+		 * them from the list (so they are not deleted later).
+		 *
+		 * This function is called only when processing DDNS, but one
+		 * never knows, so we'll rather check it
+		 */
+		if (is_apex && (chflags & KNOT_CHANGESET_TYPE_DDNS)) {
+			dbg_xfrin_detail("DDNS: returning SOA and NS to the "
+			                 "node.\n");
+			for (unsigned i = 0; i < rrsets_count; ++i) {
+				if (knot_rrset_type(rrsets[i])
+				       == KNOT_RRTYPE_SOA
+				    || knot_rrset_type(rrsets[i])
+				       == KNOT_RRTYPE_NS) {
+					dbg_xfrin_detail("Returning...\n");
+					knot_node_add_rrset(node, rrsets[i], 0);
+					rrsets[i] = NULL;
+				}
+			}
+		}
 	} else {
-		ret = xfrin_changes_check_rrsets(&changes->old_rrsets,
-		                                 &changes->old_rrsets_count,
-		                                 &changes->old_rrsets_allocated,
-		                                 1);
+		/* Remove only the RRSet with given type. */
+		/* First we must check if we're not removing NS or SOA from
+		 * apex. This change should be ignored.
+		 *
+		 * This function is called only when processing DDNS, but one
+		 * never knows, so we'll rather check it
+		 */
+		if (is_apex && (chflags & KNOT_CHANGESET_TYPE_DDNS)
+		    && (type == KNOT_RRTYPE_SOA || type == KNOT_RRTYPE_NS)) {
+			dbg_xfrin_detail("DDNS: ignoring SOA or NS removal.\n");
+			return KNOT_EOK;
+		}
+
+		rrsets = malloc(sizeof(knot_rrset_t*));
+		if (rrsets) {
+			*rrsets = knot_node_remove_rrset(node, type);
+			rrsets_count = 1;
+		}
+	}
+	
+	ret = knot_changes_rrsets_reserve(&changes->old_rrsets,
+					 &changes->old_rrsets_count,
+					 &changes->old_rrsets_allocated,
+					 rrsets_count);
+	if (ret != KNOT_EOK) {
+		dbg_xfrin("Failed to reserve changes rrsets.\n");
+		free(rrsets);
+		return ret;
+	}
+	
+	/* Mark RRsets and RDATA for removal. */
+	for (unsigned i = 0; i < rrsets_count; ++i) {
+		if (rrsets[i] == NULL) {
+			continue;
+		}
+
+		changes->old_rrsets[changes->old_rrsets_count++] = rrsets[i];
+	
+		/* Remove old RDATA. */
+		int rdata_count = knot_rrset_rdata_rr_count(rrsets[i]);
+		ret = knot_changes_rdata_reserve(&changes->old_rdata,
+						&changes->old_rdata_types,
+						changes->old_rdata_count,
+						&changes->old_rdata_allocated,
+						rdata_count);
 		if (ret != KNOT_EOK) {
-			dbg_xfrin("Failed to check changeset rrsets.\n");
+			dbg_xfrin("Failed to reserve changes rdata.\n");
+			free(rrsets);
 			return ret;
 		}
-		// remove only RRSet with the given type
-		knot_rrset_t *rrset = knot_node_remove_rrset(node, type);
-		changes->old_rrsets[changes->old_rrsets_count++] = rrset;
+		
+		knot_changes_add_rdata(changes->old_rdata,
+					changes->old_rdata_types,
+					&changes->old_rdata_count,
+					knot_rrset_get_rdata(rrsets[i]),
+					knot_rrset_type(rrsets[i]));
 	}
+	
+	free(rrsets);
 
 	return KNOT_EOK;
 }
@@ -1917,11 +1914,179 @@ static knot_node_t *xfrin_add_new_node(knot_zone_contents_t *contents,
 
 /*----------------------------------------------------------------------------*/
 
+int xfrin_replace_rrset_in_node(knot_node_t *node,
+                                       knot_rrset_t *rrset_new,
+                                       knot_changes_t *changes,
+                                       knot_zone_contents_t *contents)
+{
+	knot_rr_type_t type = knot_rrset_type(rrset_new);
+	// remove RRSet of the proper type from the node
+	dbg_xfrin_verb("Removing RRSet of type: %s.\n",
+	               knot_rrtype_to_string(type));
+	knot_rrset_t *rrset_old = knot_node_remove_rrset(node, type);
+	assert(rrset_old != NULL);
+
+	// add the old RRSet to the list of old RRSets
+	int ret = knot_changes_rrsets_reserve(&changes->old_rrsets,
+	                                     &changes->old_rrsets_count,
+	                                     &changes->old_rrsets_allocated, 1);
+	if (ret != KNOT_EOK) {
+		dbg_xfrin("Failed to add old RRSet to list.\n");
+		return ret;
+	}
+
+	// save also the RDATA, because RDATA are not deleted with the RRSet
+	// The count should be 1, but just to be sure....
+	int count = knot_rrset_rdata_rr_count(rrset_old);
+	ret = knot_changes_rdata_reserve(&changes->old_rdata,
+	                                &changes->old_rdata_types,
+	                                changes->old_rdata_count,
+	                                &changes->old_rdata_allocated, count);
+	if (ret != KNOT_EOK) {
+		dbg_xfrin("Failed to add old RDATA to list.\n");
+		return ret;
+	}
+
+	// save the new RRSet to the new RRSet, so that it is deleted if the
+	// apply fails
+	ret = knot_changes_rrsets_reserve(&changes->new_rrsets,
+	                                 &changes->new_rrsets_count,
+	                                 &changes->new_rrsets_allocated, 1);
+	if (ret != KNOT_EOK) {
+		dbg_xfrin("Failed to add new RRSet to list.\n");
+		return ret;
+	}
+
+	// The count should be 1, but just to be sure....
+	count = knot_rrset_rdata_rr_count(rrset_new);
+	// save the new RDATA
+	ret = knot_changes_rdata_reserve(&changes->new_rdata,
+	                                &changes->new_rdata_types,
+	                                changes->new_rdata_count,
+	                                &changes->new_rdata_allocated, count);
+	if (ret != KNOT_EOK) {
+		dbg_xfrin("Failed to add new RDATA to list.\n");
+		return ret;
+	}
+
+	changes->old_rrsets[changes->old_rrsets_count++] = rrset_old;
+
+	dbg_xfrin_verb("Adding RDATA from old RRSet to the list of old RDATA."
+	               "\n");
+	knot_changes_add_rdata(changes->old_rdata, changes->old_rdata_types,
+	                        &changes->old_rdata_count,
+	                        knot_rrset_get_rdata(rrset_old), type);
+
+	// store RRSIGs from the old RRSet to the new
+	knot_rrset_set_rrsigs(rrset_new, knot_rrset_get_rrsigs(rrset_old));
+
+	// insert the new RRSet to the node
+	dbg_xfrin_verb("Adding new RRSet.\n");
+	ret = knot_zone_contents_add_rrset(contents, rrset_new, &node,
+	                                   KNOT_RRSET_DUPL_SKIP, 1);
+
+	if (ret < 0) {
+		dbg_xfrin("Failed to add RRSet to node.\n");
+		return KNOT_ERROR;
+	}
+	assert(ret == 0);
+
+	changes->new_rrsets[changes->new_rrsets_count++] = rrset_new;
+
+	dbg_xfrin_verb("Adding RDATA from new RRSet to the list of new RDATA."
+	               "\n");
+	knot_changes_add_rdata(changes->new_rdata, changes->new_rdata_types,
+	                        &changes->new_rdata_count,
+	                        knot_rrset_get_rdata(rrset_new), type);
+
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
+static int xfrin_apply_add_normal_ddns(knot_changes_t *changes,
+                                       knot_rrset_t *add, knot_node_t *node,
+                                       knot_zone_contents_t *contents)
+{
+	int ret;
+
+	/* 1) Adding SOA. */
+	if (knot_rrset_type(add) == KNOT_RRTYPE_SOA) {
+		/* a) If trying to add SOA to non-apex node, or the
+		 *    serial is less than the current serial, ignore.
+		 */
+		if (knot_node_rrset(node, KNOT_RRTYPE_SOA) == NULL
+		    || ns_serial_compare(knot_rdata_soa_serial(
+		           knot_rrset_rdata(
+		               knot_node_rrset(node, KNOT_RRTYPE_SOA))),
+		           knot_rdata_soa_serial(knot_rrset_rdata(add)
+		       )) > 0
+		    ) {
+			dbg_ddns_verb("DDNS: Ignoring SOA.\n");
+			return KNOT_EOK;
+		} else {
+			dbg_ddns_verb("DDNS: replacing SOA (old serial: %u,"
+			              " new serial: %u.\n",
+			              knot_rdata_soa_serial(knot_rrset_rdata(
+			                  knot_node_rrset(node,
+			                                  KNOT_RRTYPE_SOA))),
+			              knot_rdata_soa_serial(knot_rrset_rdata(
+			                                            add)));
+			/* b) Otherwise, replace the current SOA. */
+			ret = xfrin_replace_rrset_in_node(node, add,
+			                                      changes,
+			                                      contents);
+			/* In this case we must however remove the ADD RRSet
+			 * from the changeset, so that it is not deleted
+			 * afterwards.
+			 */
+			if (ret == KNOT_EOK) {
+				return 3;
+			} else {
+				return ret;
+			}
+		}
+	} else if (knot_rrset_type(add) == KNOT_RRTYPE_CNAME) {
+		/* 2) Adding CNAME... */
+		if (knot_node_rrset(node, KNOT_RRTYPE_CNAME) != NULL) {
+			dbg_ddns_verb("DDNS: replacing CNAME.\n");
+			/* a) ... to a CNAME node => replace. */
+			ret = xfrin_replace_rrset_in_node(node, add, changes,
+			                                  contents);
+			/* In this case we must however remove the ADD RRSet
+			 * from the changeset, so that it is not deleted
+			 * afterwards.
+			 */
+			if (ret == KNOT_EOK) {
+				return 3;
+			} else {
+				return ret;
+			}
+		} else if (knot_node_rrset_count(node) > 0) {
+			dbg_ddns_verb("DDNS: ignoring CNAME (non-empty node)\n");
+			/* b) ... to a non-empty node => ignore. */
+			return KNOT_EOK;
+		}
+		/* c) ... to an empty node => process normally. */
+	} else if (knot_node_rrset(node, KNOT_RRTYPE_CNAME) != NULL) {
+		/* 3) Adding other RRSets to CNAME node => ignore. */
+		dbg_ddns_verb("DDNS: ignoring RRSet (CNAME node)\n");
+		// handled in previous case
+		assert(knot_rrset_type(add) != KNOT_RRTYPE_CNAME);
+		return KNOT_EOK;
+	}
+
+	return 1;  // Continue normal processing
+}
+
+/*----------------------------------------------------------------------------*/
+
 static int xfrin_apply_add_normal(knot_changes_t *changes,
                                   knot_rrset_t *add,
                                   knot_node_t *node,
                                   knot_rrset_t **rrset,
-                                  knot_zone_contents_t *contents)
+                                  knot_zone_contents_t *contents,
+                                  uint32_t chflags)
 {
 	assert(changes != NULL);
 	assert(add != NULL);
@@ -1935,6 +2100,15 @@ dbg_xfrin_exec_detail(
 	dbg_xfrin_detail("applying rrset:\n");
 	knot_rrset_dump(add, 0);
 );
+
+	/* DDNS special cases. */
+	if (chflags & KNOT_CHANGESET_TYPE_DDNS) {
+		ret = xfrin_apply_add_normal_ddns(changes, add, node, contents);
+		/* Continue only if return value is 1. */
+		if (ret != 1) {
+			return ret;
+		}
+	}
 	
 	int copied = 0;
 	/*! \note Reusing RRSet from previous function caused it not to be
@@ -1955,7 +2129,7 @@ dbg_xfrin_exec_detail(
 		knot_rrset_t *old = *rrset;
 
 		if (*rrset != NULL) {
-			ret = xfrin_copy_old_rrset(old, rrset, changes);
+			ret = xfrin_copy_old_rrset(old, rrset, changes, 1);
 			if (ret != KNOT_EOK) {
 				return ret;
 			}
@@ -1995,7 +2169,7 @@ dbg_xfrin_exec_detail(
 
 		if (ret < 0) {
 			dbg_xfrin("Failed to add RRSet to node.\n");
-			return KNOT_ERROR;
+			return ret;
 		}
 
 		assert(ret == 0);
@@ -2021,6 +2195,7 @@ dbg_xfrin_exec_detail(
 	 *
 	 * TODO: add the 'add' rrset to list of old RRSets?
 	 */
+
 	dbg_xfrin_detail("Merging RRSets with owners: %s, %s types: %s, %s\n",
 	                 (*rrset)->owner->name, add->owner->name,
 	                 knot_rrtype_to_string((*rrset)->type),
@@ -2039,7 +2214,7 @@ dbg_xfrin_exec_detail(
 	}
 
 	ret = knot_rrset_merge_no_dupl((void **)rrset, (void **)&add);
-	if (ret != KNOT_EOK) {
+	if (ret < 0) {
 		dbg_xfrin("Failed to merge changeset RRSet.\n");
 		return ret;
 	}
@@ -2103,7 +2278,7 @@ dbg_xfrin_exec_verb(
 		dbg_xfrin_verb("Using RRSet from previous iteration.\n");
 	} else {
 		// copy the rrset
-		ret = xfrin_copy_rrset(node, type, rrset, changes);
+		ret = xfrin_copy_rrset(node, type, rrset, changes, 1);
 		if (ret < 0) {
 			return ret;
 		} else if (ret != KNOT_EOK) {
@@ -2128,7 +2303,7 @@ dbg_xfrin_exec_verb(
 		dbg_xfrin_detail("Created new RRSet for RRSIG: %p.\n", *rrset);
 
 		// add the RRset to the list of new RRsets
-		ret = xfrin_changes_check_rrsets(
+		ret = knot_changes_rrsets_reserve(
 			&changes->new_rrsets,
 			&changes->new_rrsets_count,
 			&changes->new_rrsets_allocated, 1);
@@ -2183,7 +2358,8 @@ dbg_xfrin_exec_detail(
 				dbg_xfrin_verb("Using RRSIG from previous iteration\n");
 				rrsig = *rrsigs_old;
 			} else {
-				ret = xfrin_copy_old_rrset(old, &rrsig, changes);
+				ret = xfrin_copy_old_rrset(old, &rrsig, changes,
+				                           1);
 				if (ret != KNOT_EOK) {
 					return ret;
 				}
@@ -2202,7 +2378,7 @@ dbg_xfrin_exec_detail(
 		// merge the changeset RRSet to the copy
 		dbg_xfrin_detail("Merging RRSIG to the one in the RRSet.\n");
 		ret = knot_rrset_merge_no_dupl((void **)&rrsig, (void **)&add);
-		if (ret != KNOT_EOK) {
+		if (ret < 0) {
 			dbg_xfrin("Failed to merge changeset RRSIG to copy: %s"
 			          ".\n", knot_strerror(ret));
 			return KNOT_ERROR;
@@ -2535,10 +2711,14 @@ dbg_xfrin_exec_detail(
 		                knot_rrset_rdata(chset->remove[i]))
 		            == KNOT_RRTYPE_NSEC3))
 		{
+			dbg_xfrin_verb("Removed RRSet belongs to NSEC3 tree.\n");
 			is_nsec3 = 1;
 		}
 
 		// check if the old node is not the one we should use
+		dbg_xfrin_verb("Node:%p Owner: %p Node owner: %p\n",
+			       node, knot_rrset_owner(chset->remove[i]),
+			       knot_node_owner(node));
 		if (!node || knot_rrset_owner(chset->remove[i])
 		             != knot_node_owner(node)) {
 			if (is_nsec3) {
@@ -2559,10 +2739,12 @@ dbg_xfrin_exec_detail(
 		assert(node != NULL);
 
 		// first check if all RRSets should be removed
+		dbg_xfrin_verb("RRSet class to be removed=%u\n",
+			       knot_rrset_class(chset->remove[i]));
 		if (knot_rrset_class(chset->remove[i]) == KNOT_CLASS_ANY) {
 			ret = xfrin_apply_remove_all_rrsets(
 				changes, node,
-				knot_rrset_type(chset->remove[i]));
+				knot_rrset_type(chset->remove[i]), chset->flags);
 		} else if (knot_rrset_type(chset->remove[i])
 		           == KNOT_RRTYPE_RRSIG) {
 			// this should work also for UPDATE
@@ -2573,7 +2755,8 @@ dbg_xfrin_exec_detail(
 			// this should work also for UPDATE
 			ret = xfrin_apply_remove_normal(changes,
 			                                chset->remove[i],
-			                                node, &rrset);
+			                                node, &rrset,
+			                                chset->flags);
 		}
 
 		dbg_xfrin_detail("xfrin_apply_remove() ret = %d\n", ret);
@@ -2594,7 +2777,7 @@ static int xfrin_apply_add(knot_zone_contents_t *contents,
                            knot_changeset_t *chset,
                            knot_changes_t *changes)
 {
-	int ret = 0;
+	int ret = KNOT_EOK;
 	knot_node_t *node = NULL;
 	knot_rrset_t *rrset = NULL;
 	knot_rrset_t *rrsigs = NULL;
@@ -2661,22 +2844,27 @@ dbg_xfrin_exec_detail(
 			ret = xfrin_apply_add_rrsig(changes, chset->add[i],
 			                            node, &rrset, &rrsigs,
 			                            contents);
+			assert(ret != KNOT_EOK);
 		} else {
 			ret = xfrin_apply_add_normal(changes, chset->add[i],
-			                             node, &rrset, contents);
+			                             node, &rrset, contents,
+			                             chset->flags);
+			assert(ret <= 3);
 		}
 
-		assert(ret != KNOT_EOK);
+		// Not correct anymore, add_normal() returns KNOT_EOK if the
+		// changeset RR should be removed
+		//assert(ret != KNOT_EOK);
 
-		dbg_xfrin_detail("xfrin_apply_..() returned %s, rrset: %p\n",
-		                 knot_strerror(ret), rrset);
+		dbg_xfrin_detail("xfrin_apply_..() returned %d, rrset: %p\n",
+		                 ret, rrset);
 
 		if (ret > 0) {
 			if (ret == 1) {
 				// the ADD RRSet was used, i.e. it should be
 				// removed from the changeset and saved in the
 				// list of new RRSets
-				ret = xfrin_changes_check_rrsets(
+				ret = knot_changes_rrsets_reserve(
 					&changes->new_rrsets,
 					&changes->new_rrsets_count,
 					&changes->new_rrsets_allocated, 1);
@@ -2694,7 +2882,7 @@ dbg_xfrin_exec_detail(
 				                        chset->add[i]);
 
 				// connect the RDATA to the list of new RDATA
-				int res = xfrin_changes_check_rdata(
+				int res = knot_changes_rdata_reserve(
 					&changes->new_rdata,
 					&changes->new_rdata_types,
 					changes->new_rdata_count,
@@ -2703,7 +2891,7 @@ dbg_xfrin_exec_detail(
 					return res;
 				}
 
-				xfrin_changes_add_rdata(changes->new_rdata,
+				knot_changes_add_rdata(changes->new_rdata,
 				            changes->new_rdata_types,
 				            &changes->new_rdata_count,
 				            knot_rrset_get_rdata(chset->add[i]),
@@ -2721,6 +2909,11 @@ dbg_xfrin_exec_detail(
 				// stored in the list of new RDATA, because
 				// it is joined to the copy of RDATA, that is
 				// already stored there
+			} else if (ret == 3) {
+				// the RRSet was used and both RRSet and RDATA
+				// were properly stored. Just clear the place
+				// in the changeset
+				chset->add[i] = NULL;
 			} else {
 				assert(0);
 			}
@@ -2743,97 +2936,18 @@ static int xfrin_apply_replace_soa(knot_zone_contents_t *contents,
 	knot_node_t *node = knot_zone_contents_get_apex(contents);
 	assert(node != NULL);
 
-	int ret = 0;
-
 	assert(node != NULL);
 
-	// set the node copy as the apex of the contents
-	contents->apex = node;
-
-	// remove the SOA RRSet from the apex
-	dbg_xfrin_verb("Removing SOA.\n");
-	knot_rrset_t *rrset = knot_node_remove_rrset(node, KNOT_RRTYPE_SOA);
-	assert(rrset != NULL);
-
-	// add the old RRSet to the list of old RRSets
-	ret = xfrin_changes_check_rrsets(&changes->old_rrsets,
-	                                 &changes->old_rrsets_count,
-	                                 &changes->old_rrsets_allocated, 1);
-	if (ret != KNOT_EOK) {
-		dbg_xfrin("Failed to add old RRSet to list.\n");
-		return ret;
-	}
-
-	// save also the SOA RDATA, because RDATA are not deleted with the
-	// RRSet
-	ret = xfrin_changes_check_rdata(&changes->old_rdata,
-	                                &changes->old_rdata_types,
-	                                changes->old_rdata_count,
-	                                &changes->old_rdata_allocated, 1);
-	if (ret != KNOT_EOK) {
-		dbg_xfrin("Failed to add old RDATA to list.\n");
-		return ret;
-	}
 
-	// save the SOA to the new RRSet, so that it is deleted if the
-	// apply fails
-	ret = xfrin_changes_check_rrsets(&changes->new_rrsets,
-	                                 &changes->new_rrsets_count,
-	                                 &changes->new_rrsets_allocated, 1);
-	if (ret != KNOT_EOK) {
-		dbg_xfrin("Failed to add new RRSet to list.\n");
-		return ret;
+	int ret = xfrin_replace_rrset_in_node(node, chset->soa_to, changes,
+	                                      contents);
+	if (ret == KNOT_EOK) {
+		// remove the SOA from the changeset, so it will not be deleted
+		// after successful apply
+		chset->soa_to = NULL;
 	}
 
-	int count = knot_rrset_rdata_rr_count(rrset);
-	count += knot_rrset_rdata_rr_count(chset->soa_to);
-	// save the new SOA RDATA
-	ret = xfrin_changes_check_rdata(&changes->new_rdata,
-	                                &changes->new_rdata_types,
-	                                changes->new_rdata_count,
-	                                &changes->new_rdata_allocated, count);
-	if (ret != KNOT_EOK) {
-		dbg_xfrin("Failed to add new RDATA to list.\n");
-		return ret;
-	}
-
-	changes->old_rrsets[changes->old_rrsets_count++] = rrset;
-
-	/*! \todo Maybe check if the SOA does not have more RDATA? */
-	dbg_xfrin_verb("Adding RDATA from old SOA to the list of old RDATA.\n");
-	xfrin_changes_add_rdata(changes->old_rdata, changes->old_rdata_types,
-	                        &changes->old_rdata_count, rrset->rdata,
-	                        KNOT_RRTYPE_SOA);
-
-	// store RRSIGs from the old SOA to the new SOA
-	knot_rrset_set_rrsigs(chset->soa_to, knot_rrset_get_rrsigs(rrset));
-
-	// insert the new SOA RRSet to the node
-	dbg_xfrin_verb("Adding SOA.\n");
-	//ret = knot_node_add_rrset(node, chset->soa_to, 0);
-	ret = knot_zone_contents_add_rrset(contents, chset->soa_to, &node,
-	                                   KNOT_RRSET_DUPL_SKIP, 1);
-
-	if (ret < 0) {
-		dbg_xfrin("Failed to add RRSet to node.\n");
-		return KNOT_ERROR;
-	}
-	assert(ret == 0);
-
-	changes->new_rrsets[changes->new_rrsets_count++] = chset->soa_to;
-
-	dbg_xfrin_verb("Adding RDATA from new SOA to the list of new RDATA.\n");
-	xfrin_changes_add_rdata(changes->new_rdata,
-	                        changes->new_rdata_types,
-	                        &changes->new_rdata_count,
-	                        knot_rrset_get_rdata(chset->soa_to),
-	                        knot_rrset_type(chset->soa_to));
-
-	// remove the SOA from the changeset, so it will not be deleted after
-	// successful apply
-	chset->soa_to = NULL;
-
-	return KNOT_EOK;
+	return ret;
 }
 
 /*----------------------------------------------------------------------------*/
@@ -2885,7 +2999,7 @@ static void xfrin_mark_empty(knot_node_t *node, void *data)
 
 	if (knot_node_rrset_count(node) == 0
 	    && knot_node_children(node) == 0) {
-		int ret = xfrin_changes_check_nodes(&changes->old_nodes,
+		int ret = knot_changes_nodes_reserve(&changes->old_nodes,
 		                                 &changes->old_nodes_count,
 		                                 &changes->old_nodes_allocated);
 		if (ret != KNOT_EOK) {
@@ -2919,7 +3033,7 @@ static void xfrin_mark_empty_nsec3(knot_node_t *node, void *data)
 
 	if (knot_node_rrset_count(node) == 0
 	    && knot_node_children(node) == 0) {
-		int ret = xfrin_changes_check_nodes(&changes->old_nsec3,
+		int ret = knot_changes_nodes_reserve(&changes->old_nsec3,
 		                                 &changes->old_nsec3_count,
 		                                 &changes->old_nsec3_allocated);
 		if (ret != KNOT_EOK) {
@@ -3069,22 +3183,15 @@ static int xfrin_check_contents_copy(knot_zone_contents_t *old_contents)
 
 /*----------------------------------------------------------------------------*/
 
-int xfrin_apply_changesets(knot_zone_t *zone,
-                           knot_changesets_t *chsets,
-                           knot_zone_contents_t **new_contents)
+int xfrin_prepare_zone_copy(knot_zone_contents_t *old_contents,
+                            knot_zone_contents_t **new_contents,
+                            knot_changes_t **changes)
 {
-	if (zone == NULL || chsets == NULL || chsets->count == 0
-	    || new_contents == NULL) {
+	if (old_contents == NULL || new_contents == NULL || changes == NULL) {
 		return KNOT_EINVAL;
 	}
 
-	knot_zone_contents_t *old_contents = knot_zone_get_contents(zone);
-	if (!old_contents) {
-		dbg_xfrin("Cannot apply changesets to empty zone.\n");
-		return KNOT_EINVAL;
-	}
-
-	dbg_xfrin("Applying changesets to zone...\n");
+	dbg_xfrin("Preparing zone copy...\n");
 
 	/*
 	 * Ensure that the zone generation is set to 0.
@@ -3116,15 +3223,15 @@ int xfrin_apply_changesets(knot_zone_t *zone,
 		return ret;
 	}
 
-	knot_changes_t *changes = (knot_changes_t *)malloc(
+	knot_changes_t *chgs = (knot_changes_t *)malloc(
 	                        sizeof(knot_changes_t));
-	if (changes == NULL) {
+	if (chgs == NULL) {
 		dbg_xfrin("Failed to allocate structure for changes!\n");
-		xfrin_rollback_update(old_contents, &contents_copy, &changes);
+		xfrin_rollback_update(old_contents, &contents_copy, &chgs);
 		return KNOT_ENOMEM;
 	}
 
-	memset(changes, 0, sizeof(knot_changes_t));
+	memset(chgs, 0, sizeof(knot_changes_t));
 
 	/*!
 	 * \todo Check if all nodes have their copy.
@@ -3132,7 +3239,7 @@ int xfrin_apply_changesets(knot_zone_t *zone,
 	ret = xfrin_check_contents_copy(old_contents);
 	if (ret != KNOT_EOK) {
 		dbg_xfrin("Contents copy check failed!\n");
-		xfrin_rollback_update(old_contents, &contents_copy, &changes);
+		xfrin_rollback_update(old_contents, &contents_copy, &chgs);
 		return ret;
 	}
 
@@ -3145,30 +3252,23 @@ int xfrin_apply_changesets(knot_zone_t *zone,
 	dbg_xfrin("Switching ptrs pointing to old nodes to the new nodes.\n");
 	ret = xfrin_switch_nodes(contents_copy);
 	assert(knot_zone_contents_apex(contents_copy) != NULL);
+	
+	*new_contents = contents_copy;
+	*changes = chgs;
+	
+	return KNOT_EOK;
+}
 
-	/*
-	 * Apply the changesets.
-	 */
-	dbg_xfrin("Applying changesets.\n");
-	dbg_xfrin_verb("Old contents apex: %p, new apex: %p\n",
-	               old_contents->apex, contents_copy->apex);
-	for (int i = 0; i < chsets->count; ++i) {
-		if ((ret = xfrin_apply_changeset(contents_copy, changes,
-		                                  &chsets->sets[i]))
-		                                  != KNOT_EOK) {
-			xfrin_rollback_update(old_contents,
-			                       &contents_copy, &changes);
-			dbg_xfrin("Failed to apply changesets to zone: "
-			          "%s\n", knot_strerror(ret));
-			return ret;
-		}
-	}
-	assert(knot_zone_contents_apex(contents_copy) != NULL);
-
-	/*!
-	 * \todo Test failure of IXFR.
-	 */
+/*----------------------------------------------------------------------------*/
 
+int xfrin_finalize_updated_zone(knot_zone_contents_t *contents_copy,
+                                knot_changes_t *changes,
+                                knot_zone_contents_t *old_contents)
+{
+	if (contents_copy == NULL || changes == NULL || old_contents == NULL) {
+		return KNOT_EINVAL;
+	}
+	
 	/*
 	 * Finalize the new zone contents:
 	 * - delete empty nodes
@@ -3181,11 +3281,11 @@ int xfrin_apply_changesets(knot_zone_t *zone,
 	 * Select and remove empty nodes from zone trees. Do not free them right
 	 * away as they may be referenced by some domain names.
 	 */
-	ret = xfrin_remove_empty_nodes(contents_copy, changes);
+	int ret = xfrin_remove_empty_nodes(contents_copy, changes);
 	if (ret != KNOT_EOK) {
 		dbg_xfrin("Failed to remove empty nodes: %s\n",
 		          knot_strerror(ret));
-		xfrin_rollback_update(old_contents, &contents_copy, &changes);
+//		xfrin_rollback_update(old_contents, &contents_copy, &changes);
 		return ret;
 	}
 
@@ -3196,7 +3296,7 @@ int xfrin_apply_changesets(knot_zone_t *zone,
 	if (ret != KNOT_EOK) {
 		dbg_xfrin("Failed to finalize zone contents: %s\n",
 		          knot_strerror(ret));
-		xfrin_rollback_update(old_contents, &contents_copy, &changes);
+//		xfrin_rollback_update(old_contents, &contents_copy, &changes);
 		return ret;
 	}
 	assert(knot_zone_contents_apex(contents_copy) != NULL);
@@ -3205,6 +3305,71 @@ int xfrin_apply_changesets(knot_zone_t *zone,
 	ret = knot_zone_contents_check_loops(contents_copy);
 	if (ret != KNOT_EOK) {
 		dbg_xfrin("CNAME loop check failed: %s\n", knot_strerror(ret));
+//		xfrin_rollback_update(old_contents, &contents_copy, &changes);
+		return ret;
+	}
+	
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
+
+int xfrin_apply_changesets(knot_zone_t *zone,
+                           knot_changesets_t *chsets,
+                           knot_zone_contents_t **new_contents)
+{
+	if (zone == NULL || chsets == NULL || chsets->count == 0
+	    || new_contents == NULL) {
+		return KNOT_EINVAL;
+	}
+
+	knot_zone_contents_t *old_contents = knot_zone_get_contents(zone);
+	if (!old_contents) {
+		dbg_xfrin("Cannot apply changesets to empty zone.\n");
+		return KNOT_EINVAL;
+	}
+
+	dbg_xfrin("Applying changesets to zone...\n");
+
+	dbg_xfrin_verb("Creating shallow copy of the zone...\n");
+	knot_zone_contents_t *contents_copy = NULL;
+	knot_changes_t *changes = NULL;
+	int ret = xfrin_prepare_zone_copy(old_contents, &contents_copy,
+	                                  &changes);
+	if (ret != KNOT_EOK) {
+		dbg_xfrin("Failed to prepare zone copy: %s\n",
+		          knot_strerror(ret));
+		return ret;
+	}
+
+	/*
+	 * Apply the changesets.
+	 */
+	dbg_xfrin("Applying changesets.\n");
+	dbg_xfrin_verb("Old contents apex: %p, new apex: %p\n",
+	               old_contents->apex, contents_copy->apex);
+	for (int i = 0; i < chsets->count; ++i) {
+		if ((ret = xfrin_apply_changeset(contents_copy, changes,
+		                                  &chsets->sets[i]))
+		                                  != KNOT_EOK) {
+			xfrin_rollback_update(old_contents,
+			                       &contents_copy, &changes);
+			dbg_xfrin("Failed to apply changesets to zone: "
+			          "%s\n", knot_strerror(ret));
+			return ret;
+		}
+	}
+	assert(knot_zone_contents_apex(contents_copy) != NULL);
+
+	/*!
+	 * \todo Test failure of IXFR.
+	 */
+
+	dbg_xfrin_verb("Finalizing updated zone...\n");
+	ret = xfrin_finalize_updated_zone(contents_copy, changes, old_contents);
+	if (ret != KNOT_EOK) {
+		dbg_xfrin("Failed to finalize updated zone: %s\n",
+		          knot_strerror(ret));
 		xfrin_rollback_update(old_contents, &contents_copy, &changes);
 		return ret;
 	}
@@ -3237,7 +3402,7 @@ int xfrin_switch_zone(knot_zone_t *zone,
 	               old, (old) ? old->apex : NULL, new_contents->apex);
 
 	// switch pointers in domain names, now only the new zone is used
-	if (transfer_type == XFR_TYPE_IIN) {
+	if (transfer_type == XFR_TYPE_IIN || transfer_type == XFR_TYPE_UPDATE) {
 		// Traverse also the dname table and change the node pointers
 		// in dnames
 		int ret = knot_zone_contents_dname_table_apply(
diff --git a/src/libknot/updates/xfr-in.h b/src/libknot/updates/xfr-in.h
index a762b81..c65e708 100644
--- a/src/libknot/updates/xfr-in.h
+++ b/src/libknot/updates/xfr-in.h
@@ -185,6 +185,14 @@ int xfrin_apply_changesets(knot_zone_t *zone,
                            knot_changesets_t *chsets,
                            knot_zone_contents_t **new_contents);
 
+int xfrin_prepare_zone_copy(knot_zone_contents_t *old_contents,
+                            knot_zone_contents_t **new_contents,
+                            knot_changes_t **changes);
+
+int xfrin_finalize_updated_zone(knot_zone_contents_t *contents_copy,
+                                knot_changes_t *changes,
+                                knot_zone_contents_t *old_contents);
+
 int xfrin_switch_zone(knot_zone_t *zone,
                       knot_zone_contents_t *new_contents,
                       int deep_free);
@@ -195,6 +203,18 @@ void xfrin_rollback_update(knot_zone_contents_t *old_contents,
                            knot_zone_contents_t **new_contents,
                            knot_changes_t **changes);
 
+int xfrin_copy_rrset(knot_node_t *node, knot_rr_type_t type,
+                     knot_rrset_t **rrset, knot_changes_t *changes, 
+                     int save_new);
+
+int xfrin_copy_old_rrset(knot_rrset_t *old, knot_rrset_t **copy,
+                         knot_changes_t *changes, int save_new);
+
+int xfrin_replace_rrset_in_node(knot_node_t *node,
+                                knot_rrset_t *rrset_new,
+                                knot_changes_t *changes,
+                                knot_zone_contents_t *contents);
+
 #endif /* _KNOTXFR_IN_H_ */
 
 /*! @} */
diff --git a/src/libknot/util/debug.h b/src/libknot/util/debug.h
index 731fed8..abe335b 100644
--- a/src/libknot/util/debug.h
+++ b/src/libknot/util/debug.h
@@ -68,6 +68,7 @@
 #ifdef KNOT_XFR_DEBUG
   #define KNOT_XFRIN_DEBUG
   #define KNOT_TSIG_DEBUG
+  #define KNOT_DDNS_DEBUG
 #endif
 
 /* KNOT_DNAME_DEBUG -- in configure.ac */
@@ -758,27 +759,33 @@ void knot_zone_contents_dump(knot_zone_contents_t *zone, char loaded_zone);
 #ifdef DEBUG_ENABLE_BRIEF
 #define dbg_ddns(msg...) log_msg(LOG_ZONE, LOG_DEBUG, msg)
 #define dbg_ddns_hex(data, len)  hex_log(LOG_ZONE, (data), (len))
+#define dbg_ddns_exec(cmds) do { cmds } while (0)
 #else
 #define dbg_ddns(msg...)
 #define dbg_ddns_hex(data, len)
+#define dbg_ddns_exec(cmds)
 #endif
 
 /* Verbose messages. */
 #ifdef DEBUG_ENABLE_VERBOSE
 #define dbg_ddns_verb(msg...) log_msg(LOG_ZONE, LOG_DEBUG, msg)
 #define dbg_ddns_hex_verb(data, len)  hex_log(LOG_ZONE, (data), (len))
+#define dbg_ddns_exec_verb(cmds) do { cmds } while (0)
 #else
 #define dbg_ddns_verb(msg...)
 #define dbg_ddns_hex_verb(data, len)
+#define dbg_ddns_exec_verb(cmds)
 #endif
 
 /* Detail messages. */
 #ifdef DEBUG_ENABLE_DETAILS
 #define dbg_ddns_detail(msg...) log_msg(LOG_ZONE, LOG_DEBUG, msg)
 #define dbg_ddns_hex_detail(data, len)  hex_log(LOG_ZONE, (data), (len))
+#define dbg_ddns_exec_detail(cmds) do { cmds } while (0)
 #else
 #define dbg_ddns_detail(msg...)
 #define dbg_ddns_hex_detail(data, len)
+#define dbg_ddns_exec_detail(cmds)
 #endif
 
 /* No messages. */
@@ -786,9 +793,12 @@ void knot_zone_contents_dump(knot_zone_contents_t *zone, char loaded_zone);
 #define dbg_ddns(msg...)
 #define dbg_ddns_hex(data, len)
 #define dbg_ddns_verb(msg...)
+#define dbg_ddns_exec(cmds)
 #define dbg_ddns_hex_verb(data, len)
+#define dbg_ddns_exec_verb(cmds)
 #define dbg_ddns_detail(msg...)
 #define dbg_ddns_hex_detail(data, len)
+#define dbg_ddns_exec_detail(cmds)
 #endif
 
 #ifdef KNOT_TSIG_DEBUG
diff --git a/src/libknot/util/descriptor.c b/src/libknot/util/descriptor.c
index 1588a2e..8cab6b4 100644
--- a/src/libknot/util/descriptor.c
+++ b/src/libknot/util/descriptor.c
@@ -68,6 +68,15 @@ static knot_lookup_table_t dns_rrclasses[] = {
 	{ 0, NULL }
 };
 
+/*! \brief DS digest lengths. */
+enum knot_ds_algorithm_len
+{
+	KNOT_DS_DIGEST_LEN_SHA1 = 20,	/* 20B - RFC 3658 */
+	KNOT_DS_DIGEST_LEN_SHA256 = 32,	/* 32B - RFC 4509 */
+	KNOT_DS_DIGEST_LEN_GOST = 32,	/* 32B - RFC 5933 */
+	KNOT_DS_DIGEST_LEN_SHA384 = 48	/* 48B - RFC 6605 */
+};
+
 /*! \brief RR type descriptors. */
 static knot_rrtype_descriptor_t
        knot_rrtype_descriptors[KNOT_RRTYPE_DESCRIPTORS_LENGTH] = {
@@ -572,5 +581,21 @@ int knot_rrtype_is_metatype(uint16_t type)
 	        || type == KNOT_RRTYPE_OPT);
 }
 
+size_t knot_ds_digest_length(uint8_t algorithm)
+{
+	switch (algorithm) {
+		case KNOT_DS_ALG_SHA1:
+			return KNOT_DS_DIGEST_LEN_SHA1;
+		case KNOT_DS_ALG_SHA256:
+			return KNOT_DS_DIGEST_LEN_SHA256;
+		case KNOT_DS_ALG_GOST:
+			return KNOT_DS_DIGEST_LEN_GOST;
+		case KNOT_DS_ALG_SHA384:
+			return KNOT_DS_DIGEST_LEN_SHA384;
+		default:
+			return 0;
+	}
+}
+
 /*! @} */
 
diff --git a/src/libknot/util/descriptor.h b/src/libknot/util/descriptor.h
index 6364e5b..23b5d13 100644
--- a/src/libknot/util/descriptor.h
+++ b/src/libknot/util/descriptor.h
@@ -237,6 +237,41 @@ typedef enum knot_rdata_zoneformat knot_rdata_zoneformat_t;
 /*! \brief Enum containing wireformat codes. */
 typedef enum knot_rdatawireformat knot_rdata_wireformat_t;
 
+/*! \brief Constants for DNSSEC algorithm types.
+ *
+ * Source: http://www.iana.org/assignments/dns-sec-alg-numbers/dns-sec-alg-numbers.xml
+ */
+enum knot_dnssec_algorithm
+{
+	KNOT_DNSSEC_ALG_RSAMD5 = 1,
+	KNOT_DNSSEC_ALG_DH = 2,
+	KNOT_DNSSEC_ALG_DSA = 3,
+	KNOT_DNSSEC_ALG_RSASHA1 = 5,
+	KNOT_DNSSEC_ALG_DSA_NSEC3_SHA1 = 6,
+	KNOT_DNSSEC_ALG_RSASHA1_NSEC3_SHA1 = 7,
+	KNOT_DNSSEC_ALG_RSASHA256 = 8,
+	KNOT_DNSSEC_ALG_RSASHA512 = 10,
+	KNOT_DNSSEC_ALG_ECC_GOST = 12,
+	KNOT_DNSSEC_ALG_ECDSAP256SHA256 = 13,
+	KNOT_DNSSEC_ALG_ECDSAP384SHA384 = 14
+};
+
+typedef enum knot_dnssec_algorithm knot_dnssec_algorithm_t;
+
+/*! \brief Constants for DNSSEC algorithm types.
+ *
+ * Source: http://www.iana.org/assignments/ds-rr-types/ds-rr-types.xml
+ */
+enum knot_ds_algorithm
+{
+	KNOT_DS_ALG_SHA1 = 1,	/* 20B - RFC 3658 */
+	KNOT_DS_ALG_SHA256 = 2,	/* 32B - RFC 4509 */
+	KNOT_DS_ALG_GOST = 3,	/* 32B - RFC 5933 */
+	KNOT_DS_ALG_SHA384 = 4	/* 48B - RFC 6605 */
+};
+
+typedef enum knot_ds_algorithm knot_ds_algorithm_t;
+
 /*! \brief Structure holding RR descriptor. */
 struct knot_rrtype_descriptor {
 	uint16_t type;          /*!< RR type */
@@ -328,6 +363,8 @@ size_t knot_wireformat_size(unsigned int wire_type);
 
 int knot_rrtype_is_metatype(uint16_t type);
 
+size_t knot_ds_digest_length(uint8_t algorithm);
+
 #endif /* _KNOT_DESCRIPTOR_H_ */
 
 /*! @} */
diff --git a/src/libknot/zone/zone-contents.c b/src/libknot/zone/zone-contents.c
index 61e9e51..bdc268b 100644
--- a/src/libknot/zone/zone-contents.c
+++ b/src/libknot/zone/zone-contents.c
@@ -408,6 +408,40 @@ static void knot_zone_contents_adjust_rdata_item(knot_rdata_t *rdata,
 }
 
 /*----------------------------------------------------------------------------*/
+
+static int knot_zone_contents_adjust_rdata(knot_rdata_t *rdata,
+                                           knot_rrtype_descriptor_t *desc,
+                                           knot_zone_contents_t *zone,
+                                           knot_node_t *node)
+{
+	for (int i = 0; i < rdata->count; ++i) {
+		if (desc->wireformat[i]
+		    == KNOT_RDATA_WF_COMPRESSED_DNAME
+		    || desc->wireformat[i]
+		       == KNOT_RDATA_WF_UNCOMPRESSED_DNAME
+		    || desc->wireformat[i]
+		       == KNOT_RDATA_WF_LITERAL_DNAME) {
+			dbg_zone_detail("Adjusting domain name at position %d"
+			                " of the RDATA\n", i);
+			knot_zone_contents_adjust_rdata_item(rdata, zone, node,
+			                                     i);
+		}
+	}
+
+	/*
+	 * DS digest length check (#2050).
+	 */
+	int ret;
+	if (desc->type == KNOT_RRTYPE_DS
+	    && (ret = knot_rdata_ds_check(rdata)) != KNOT_EOK) {
+		dbg_zone("DS RDATA check failed: %s\n", knot_strerror(ret));
+		return KNOT_EMALF;
+	}
+
+	return KNOT_EOK;
+}
+
+/*----------------------------------------------------------------------------*/
 /*!
  * \brief Adjusts all RDATA in the given RRSet by replacing domain names by ones
  *        present in the zone.
@@ -419,9 +453,9 @@ static void knot_zone_contents_adjust_rdata_item(knot_rdata_t *rdata,
  * \param rrset RRSet to adjust RDATA in.
  * \param zone Zone to which the RRSet belongs.
  */
-static void knot_zone_contents_adjust_rdata_in_rrset(knot_rrset_t *rrset,
-                                                     knot_zone_contents_t *zone,
-                                                     knot_node_t *node)
+static int knot_zone_contents_adjust_rdata_in_rrset(knot_rrset_t *rrset,
+                                                    knot_zone_contents_t *zone,
+                                                    knot_node_t *node)
 {
 	uint16_t type = knot_rrset_type(rrset);
 
@@ -433,49 +467,37 @@ static void knot_zone_contents_adjust_rdata_in_rrset(knot_rrset_t *rrset,
 	knot_rdata_t *rdata = rdata_first;
 
 	if (rdata == NULL) {
-		return;
+		return KNOT_EOK;
 	}
 
+	int i = 1;
+	int ret;
 	while (rdata->next != rdata_first) {
-		for (int i = 0; i < rdata->count; ++i) {
-			if (desc->wireformat[i]
-			    == KNOT_RDATA_WF_COMPRESSED_DNAME
-			    || desc->wireformat[i]
-			       == KNOT_RDATA_WF_UNCOMPRESSED_DNAME
-			    || desc->wireformat[i]
-			       == KNOT_RDATA_WF_LITERAL_DNAME) {
-				dbg_zone("Adjusting domain name at "
-				  "position %d of RDATA of record with owner "
-				  "%s and type %s.\n",
-				  i, rrset->owner->name,
-				  knot_rrtype_to_string(type));
-
-				knot_zone_contents_adjust_rdata_item(rdata,
-				                                     zone, node,
-				                                     i);
-			}
+dbg_zone_exec_detail(
+		char *name = knot_dname_to_str(knot_rrset_owner(rrset));
+		dbg_zone_detail("Adjusting domain name at %d. RDATA of RRSet "
+		                "with owner %s and type %s.\n", i, name,
+		                knot_rrtype_to_string(type));
+		free(name);
+);
+		ret = knot_zone_contents_adjust_rdata(rdata, desc,
+		                                      zone, node);
+		if (ret != KNOT_EOK) {
+			return ret;
 		}
-		rdata = rdata->next;
-	}
 
-	for (int i = 0; i < rdata->count; ++i) {
-		if (desc->wireformat[i]
-		    == KNOT_RDATA_WF_COMPRESSED_DNAME
-		    || desc->wireformat[i]
-		       == KNOT_RDATA_WF_UNCOMPRESSED_DNAME
-		    || desc->wireformat[i]
-		       == KNOT_RDATA_WF_LITERAL_DNAME) {
-			dbg_zone("Adjusting domain name at "
-			  "position %d of RDATA of record with owner "
-			  "%s and type %s.\n",
-			  i, rrset->owner->name,
-			  knot_rrtype_to_string(type));
-
-			knot_zone_contents_adjust_rdata_item(rdata, zone, node,
-			                                     i);
-		}
+		rdata = rdata->next;
+		++i;
 	}
 
+dbg_zone_exec_detail(
+	char *name = knot_dname_to_str(knot_rrset_owner(rrset));
+	dbg_zone_detail("Adjusting domain name at %d. RDATA of RRSet "
+			"with owner %s and type %s.\n", i, name,
+			 knot_rrtype_to_string(type));
+	free(name);
+);
+	return knot_zone_contents_adjust_rdata(rdata, desc, zone, node);
 }
 
 /*----------------------------------------------------------------------------*/
@@ -489,28 +511,37 @@ static void knot_zone_contents_adjust_rdata_in_rrset(knot_rrset_t *rrset,
  * \param node Zone node to adjust the RRSets in.
  * \param zone Zone to which the node belongs.
  */
-static void knot_zone_contents_adjust_rrsets(knot_node_t *node,
-                                             knot_zone_contents_t *zone)
+static int knot_zone_contents_adjust_rrsets(knot_node_t *node,
+                                            knot_zone_contents_t *zone)
 {
 	knot_rrset_t **rrsets = knot_node_get_rrsets(node);
 	short count = knot_node_rrset_count(node);
 
 	assert(count == 0 || rrsets != NULL);
+	int ret = KNOT_EOK;
 
 	for (int r = 0; r < count; ++r) {
 		assert(rrsets[r] != NULL);
 		dbg_zone("Adjusting next RRSet.\n");
-		knot_zone_contents_adjust_rdata_in_rrset(rrsets[r], zone,
-		                                           node);
+		ret = knot_zone_contents_adjust_rdata_in_rrset(rrsets[r], zone,
+		                                               node);
+
 		knot_rrset_t *rrsigs = rrsets[r]->rrsigs;
-		if (rrsigs != NULL) {
+		if (ret == KNOT_EOK && rrsigs != NULL) {
 			dbg_zone("Adjusting next RRSIGs.\n");
-			knot_zone_contents_adjust_rdata_in_rrset(rrsigs, zone,
-			                                         node);
+			ret = knot_zone_contents_adjust_rdata_in_rrset(rrsigs,
+			                                               zone,
+			                                               node);
+		}
+
+		if (ret != KNOT_EOK) {
+			break;
 		}
 	}
 
 	free(rrsets);
+
+	return ret;
 }
 /*----------------------------------------------------------------------------*/
 /*!
@@ -529,12 +560,15 @@ static void knot_zone_contents_adjust_rrsets(knot_node_t *node,
  *       in the inserting function, though that may not be always used (e.g.
  *       old changeset processing).
  */
-static void knot_zone_contents_adjust_node(knot_node_t *node,
-                                           knot_zone_contents_t *zone)
+static int knot_zone_contents_adjust_node(knot_node_t *node,
+                                          knot_zone_contents_t *zone)
 {
 	// adjust domain names in RDATA
 	/*! \note Enabled again after a LONG time. Should test thoroughly. */
-	knot_zone_contents_adjust_rrsets(node, zone);
+	int ret = knot_zone_contents_adjust_rrsets(node, zone);
+	if (ret != KNOT_EOK) {
+		return ret;
+	}
 
 	// assure that owner has proper node
 	if (knot_dname_node(knot_node_owner(node)) == NULL) {
@@ -566,6 +600,8 @@ static void knot_zone_contents_adjust_node(knot_node_t *node,
 	                knot_node_is_deleg_point(node) ? "yes" : "no");
 	dbg_zone_detail("Non-authoritative: %s\n",
 	                knot_node_is_non_auth(node) ? "yes" : "no");
+
+	return KNOT_EOK;
 }
 
 /*----------------------------------------------------------------------------*/
@@ -621,7 +657,12 @@ dbg_zone_exec_verb(
 	 * 2) Do other adjusting (flags, closest enclosers, wildcard children,
 	 *    etc.).
 	 */
-	knot_zone_contents_adjust_node(node, zone);
+	ret = knot_zone_contents_adjust_node(node, zone);
+	if (ret != KNOT_EOK) {
+		dbg_xfrin("Failed to adjust node: %s\n", knot_strerror(ret));
+		args->err = ret;
+		return;
+	}
 }
 
 /*----------------------------------------------------------------------------*/
@@ -816,10 +857,10 @@ dbg_zone_exec_verb(
 	dbg_zone("\n");
 
 	char *name_b32 = NULL;
-	size_t size = base32hex_encode_alloc((char *)hashed_name, hash_size,
-	                                     &name_b32);
+	int32_t b32_ret = base32hex_encode_alloc(hashed_name, hash_size,
+	                                            (uint8_t **)(&name_b32));
 
-	if (size == 0) {
+	if (b32_ret <= 0) {
 		char *n = knot_dname_to_str(name);
 		dbg_zone("Error while encoding hashed name %s to base32.\n", n);
 		free(n);
@@ -829,6 +870,8 @@ dbg_zone_exec_verb(
 		return KNOT_ECRYPTO;
 	}
 
+	size_t size = b32_ret;
+
 	assert(name_b32 != NULL);
 	free(hashed_name);
 
@@ -1316,22 +1359,21 @@ dbg_zone_exec_detail(
 		return ret;
 	}
 
-	ret = knot_zone_tree_insert(zone->nodes, node);
-	if (ret != KNOT_EOK) {
-		dbg_zone("Failed to insert node into zone tree.\n");
-		return ret;
-	}
-
 	if (use_domain_table) {
 		ret = knot_zone_contents_dnames_from_node_to_table(
 		          zone->dname_table, node);
 		if (ret != KNOT_EOK) {
-			/*! \todo Remove node from the tree and hash table.*/
 			dbg_zone("Failed to add dnames into table.\n");
 			return ret;
 		}
 	}
 
+	ret = knot_zone_tree_insert(zone->nodes, node);
+	if (ret != KNOT_EOK) {
+		dbg_zone("Failed to insert node into zone tree.\n");
+		return ret;
+	}
+
 #ifdef USE_HASH_TABLE
 	// add the node also to the hash table if authoritative, or deleg. point
 	if (zone->table != NULL
@@ -1339,7 +1381,10 @@ dbg_zone_exec_detail(
 	                      (const char *)node->owner->name,
 	                      node->owner->size, (void *)node) != 0) {
 		dbg_zone("Error inserting node into hash table!\n");
-		/*! \todo Remove the node from the tree. */
+		knot_zone_tree_node_t *removed;
+		(void)knot_zone_tree_remove(zone->nodes, knot_node_owner(node),
+		                            &removed);
+		assert(removed->node == node);
 		return KNOT_EHASH;
 	}
 #endif
@@ -2119,7 +2164,7 @@ const knot_node_t *knot_zone_contents_find_previous_nsec3(
 
 static void knot_zone_contents_left_chop(char *name, size_t *size)
 {
-	short label_size = name[0];
+	short label_size = (unsigned char)name[0];
 	
 	memmove(name, name + label_size + 1, *size -label_size - 1);
 	*size = *size - label_size - 1;
diff --git a/src/libknot/zone/zone-diff.c b/src/libknot/zone/zone-diff.c
index 734c7c2..a4efff9 100644
--- a/src/libknot/zone/zone-diff.c
+++ b/src/libknot/zone/zone-diff.c
@@ -163,11 +163,11 @@ static int knot_zone_diff_changeset_add_rrset(knot_changeset_t *changeset,
 	}
 	if (rrset_copy->rrsigs != NULL) {
 		knot_rrset_deep_free(&rrset_copy->rrsigs, 1, 1, 1);
-	}	
+	}
 	assert(knot_rrset_rrsigs(rrset_copy) == NULL);
 	
 	ret = knot_changeset_add_new_rr(changeset, rrset_copy,
-	                                    XFRIN_CHANGESET_ADD);
+	                                    KNOT_CHANGESET_ADD);
 	if (ret != KNOT_EOK) {
 		/* We have to free the copy now! */
 		knot_rrset_deep_free(&rrset_copy, 1, 1, 1);
@@ -193,6 +193,7 @@ static int knot_zone_diff_changeset_remove_rrset(knot_changeset_t *changeset,
 	}
 	
 	if (knot_rrset_rdata_rr_count(rrset) == 0) {
+		/* RDATA are the same, however*/
 		dbg_zonediff_detail("zone_diff: Nothing to remove.\n");
 		return KNOT_EOK;
 	}
@@ -209,11 +210,12 @@ static int knot_zone_diff_changeset_remove_rrset(knot_changeset_t *changeset,
 	}
 	if (rrset_copy->rrsigs != NULL) {
 		knot_rrset_deep_free(&rrset_copy->rrsigs, 1, 1, 1);
-	}	
+	}
+	
 	assert(knot_rrset_rrsigs(rrset_copy) == NULL);
 	
 	ret = knot_changeset_add_new_rr(changeset, rrset_copy,
-	                                    XFRIN_CHANGESET_REMOVE);
+	                                    KNOT_CHANGESET_REMOVE);
 	if (ret != KNOT_EOK) {
 		/* We have to free the copy now. */
 		knot_rrset_deep_free(&rrset_copy, 1, 1, 1);
@@ -251,6 +253,19 @@ static int knot_zone_diff_add_node(const knot_node_t *node,
 			free(rrsets);
 			return ret;
 		}
+		
+		if (knot_rrset_rrsigs(rrsets[i])) {
+			/* Add RRSIGs of the new node. */
+			ret = knot_zone_diff_changeset_add_rrset(changeset,
+						knot_rrset_rrsigs(rrsets[i]));
+			if (ret != KNOT_EOK) {
+				dbg_zonediff("zone_diff: add_node: Cannot "
+				             "add RRSIG (%s).\n",
+				       knot_strerror(ret));
+				free(rrsets);
+				return ret;
+			}
+		}
 	}
 	
 	free(rrsets);
@@ -292,6 +307,18 @@ dbg_zonediff_exec_detail(
 			free(rrsets);
 			return ret;
 		}
+		if (knot_rrset_rrsigs(rrsets[i])) {
+			/* Remove RRSIGs of the old node. */
+			ret = knot_zone_diff_changeset_remove_rrset(changeset,
+						knot_rrset_rrsigs(rrsets[i]));
+			if (ret != KNOT_EOK) {
+				dbg_zonediff("zone_diff: remove_node: Cannot "
+				             "remove RRSIG (%s).\n",
+				       knot_strerror(ret));
+				free(rrsets);
+				return ret;
+			}
+		}
 	}
 	
 	free(rrsets);
@@ -356,8 +383,8 @@ static int knot_zone_diff_rdata_return_changes(const knot_rrset_t *rrset1,
 			 * because the list was traversed - there's no match.
 			 */
 			dbg_zonediff("zone_diff: diff_rdata: "
-			       "No match for RR (type=%s owner=%s).\n",
-			       knot_rrtype_to_string(knot_rrset_type(rrset1)),
+			       "No match for RR (type=%u owner=%s).\n",
+			       knot_rrset_type(rrset1),
 			       knot_dname_to_str(rrset1->owner));
 			/* Make a copy of tmp_rdata. */
 			knot_rdata_t *tmp_rdata_copy =
@@ -457,7 +484,7 @@ static int knot_zone_diff_rdata(const knot_rrset_t *rrset1,
 	}
 	
 	int ret = knot_zone_diff_changeset_remove_rrset(changeset,
-	                                            to_remove);
+	                                                to_remove);
 	if (ret != KNOT_EOK) {
 		knot_rrset_deep_free(&to_remove, 1, 1, 1);
 		dbg_zonediff("zone_diff: diff_rdata: Could not remove RRs. "
@@ -587,12 +614,13 @@ static int knot_zone_diff_rrsets(const knot_rrset_t *rrset1,
 	int ret = knot_zone_diff_rdata(knot_rrset_rrsigs(rrset1),
 	                               knot_rrset_rrsigs(rrset2), changeset);
 	if (ret != KNOT_EOK) {
-		dbg_zonediff("zone_diff: diff_rrsets (%s:%s): Failed to diff RRSIGs. "
-		       "They were: %p %p. (%s).\n",
-		       knot_dname_to_str(rrset1->owner),
-		       knot_rrtype_to_string(rrset1->type),
-		       rrset1->rrsigs,
-		       rrset2->rrsigs, knot_strerror(ret));
+		dbg_zonediff("zone_diff: diff_rrsets (%s:%s): "
+		             "Failed to diff RRSIGs. "
+		             "They were: %p %p. (%s).\n",
+		             knot_dname_to_str(rrset1->owner),
+		             knot_rrtype_to_string(rrset1->type),
+		             rrset1->rrsigs,
+		             rrset2->rrsigs, knot_strerror(ret));
 	}
 
 	/* RRs (=rdata) have to be cross-compared, unfortunalely. */
@@ -706,6 +734,20 @@ static void knot_zone_diff_node(knot_node_t *node, void *data)
 				free(rrsets);
 				return;
 			}
+			
+			/* Remove RRSet's RRSIGs as well. */
+			if (knot_rrset_rrsigs(rrset)) {
+				ret = knot_zone_diff_changeset_remove_rrset(
+				            param->changeset,
+				            knot_rrset_rrsigs(rrset));
+				if (ret != KNOT_EOK) {
+				    dbg_zonediff("zone_diff: diff_node+: "
+				                 "Failed to remove RRSIGs.\n");
+				    param->ret = ret;
+				    free(rrsets);
+				    return;
+				}
+			}
 		} else {
 			dbg_zonediff("zone_diff: diff_node: There is a counterpart "
 			       "for RRSet of type %s in second tree.\n",
@@ -790,6 +832,18 @@ static void knot_zone_diff_node(knot_node_t *node, void *data)
 				free(rrsets);
 				return;
 			}
+			if (knot_rrset_rrsigs(rrset)) {
+				int ret = knot_zone_diff_changeset_add_rrset(
+			        param->changeset,
+			         knot_rrset_rrsigs(rrset));
+			   if (ret != KNOT_EOK) {
+			     dbg_zonediff("zone_diff: diff_node: "
+			            "Failed to add RRSIGs.\n");
+			    param->ret = ret;
+					free(rrsets);
+				return;	
+			 }
+			}
 		} else {
 			/* Already handled. */
 			;
@@ -989,7 +1043,10 @@ int knot_zone_diff_create_changesets(const knot_zone_contents_t *z1,
 		return KNOT_EINVAL;
 	}
 	/* Create changesets. */
-	int ret = knot_changeset_allocate(changesets);
+	/* Setting type to IXFR - that's the default, DDNS triggers special
+	 * processing when applied. See #2110 and #2111.
+	 */
+	int ret = knot_changeset_allocate(changesets, KNOT_CHANGESET_TYPE_IXFR);
 	if (ret != KNOT_EOK) {
 		dbg_zonediff("zone_diff: create_changesets: "
 		             "Could not allocate changesets."
@@ -1014,14 +1071,13 @@ int knot_zone_diff_create_changesets(const knot_zone_contents_t *z1,
 dbg_zonediff_exec_detail(
 	knot_zone_diff_dump_changeset((*changesets)->sets);
 );
-	
 	return KNOT_EOK;
 }
 
-/* Mostly just for testing. We only shall diff zones in memory later. */
+///* Mostly just for testing. We only shall diff zones in memory later. */
 //int knot_zone_diff_zones(const char *zonefile1, const char *zonefile2)
 //{
-	/* Compile test zones. */
+//	/* Compile test zones. */
 //	int ret = zone_read("example.com.", "/home/jan/test/testzone1", "tmpzone1.db", 0);
 //	assert(ret == KNOT_EOK);
 //	ret = zone_read("example.com.", "/home/jan/test/testzone2", "tmpzone2.db", 0);
@@ -1040,29 +1096,29 @@ dbg_zonediff_exec_detail(
 //	assert(knot_zone_contents_diff(z1->contents, z2->contents,
 //	                               changeset) == KNOT_EOK);
 //	dbg_zonediff("Changeset created: From=%d to=%d.\n", changeset.serial_from,
-//	       changeset.serial_to);
-////	knot_changesets_t chngsets;
-////	chngsets->sets = malloc(sizeof(knot_changeset_t));
-////	chngsets->sets[0] = changeset;
-////	chngsets->count = 1;
-////	chngsets->allocated = 1;
-////	knot_zone_contents_t *new_zone = NULL;
-////	ret = xfrin_apply_changesets(z1, chngsets, &new_zone);
-////	if (ret != KNOT_EOK) {
-////		dbg_zonediff("Application of changesets failed. (%s)\n",
-////		       knot_strerror(ret));
-////	}
+//	             changeset.serial_to);
+//	//	knot_changesets_t chngsets;
+//	//	chngsets->sets = malloc(sizeof(knot_changeset_t));
+//	//	chngsets->sets[0] = changeset;
+//	//	chngsets->count = 1;
+//	//	chngsets->allocated = 1;
+//	//	knot_zone_contents_t *new_zone = NULL;
+//	//	ret = xfrin_apply_changesets(z1, chngsets, &new_zone);
+//	//	if (ret != KNOT_EOK) {
+//	//		dbg_zonediff("Application of changesets failed. (%s)\n",
+//	//		       knot_strerror(ret));
+//	//	}
 	
-////	assert(new_zone);
+//	//	assert(new_zone);
 	
 //	/* Dump creted zone. */
-////	FILE *f = fopen("testovani", "w");
-////	zone_dump_text(new_zone, f);
+//	//	FILE *f = fopen("testovani", "w");
+//	//	zone_dump_text(new_zone, f);
 	
 //	knot_zone_deep_free(&z2, 0);
 //	knot_zone_deep_free(&z1, 0);
-////	knot_zone_contents_deep_free(&new_zone, 1);
-////	knot_zone_free(&z1);
+//	//	knot_zone_contents_deep_free(&new_zone, 1);
+//	//	knot_zone_free(&z1);
 	
 //	knot_free_changeset(&changeset);
 //	exit(0);
diff --git a/src/tests/common/base32hex_tests.c b/src/tests/common/base32hex_tests.c
new file mode 100644
index 0000000..cdfec69
--- /dev/null
+++ b/src/tests/common/base32hex_tests.c
@@ -0,0 +1,166 @@
+/*  Copyright (C) 2011 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "tests/common/base32hex_tests.h"
+
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "common/base32hex.h"
+
+#define BUF_LEN 256
+
+static int base32hex_tests_count(int argc, char *argv[]);
+static int base32hex_tests_run(int argc, char *argv[]);
+
+unit_api base32hex_tests_api = {
+	"Base32hex encoding",
+	&base32hex_tests_count,
+	&base32hex_tests_run
+};
+
+static int base32hex_tests_count(int argc, char *argv[])
+{
+	return 42;
+}
+
+static int base32hex_tests_run(int argc, char *argv[])
+{
+	int32_t  ret;
+	uint8_t  in[BUF_LEN], ref[BUF_LEN], out[BUF_LEN], out2[BUF_LEN];
+	uint32_t in_len, ref_len;
+
+	// 1. test vector -> ENC -> DEC
+	strcpy((char *)in, "");
+	in_len = strlen((char *)in);
+	strcpy((char *)ref, "");
+	ref_len = strlen((char *)ref);
+	ret = base32hex_encode(in, in_len, out, BUF_LEN);
+	cmp_ok(ret, "==", ref_len, "1. test vector - ENC output length");
+	ok(memcmp(out, ref, ret) == 0, "1. test vector - ENC output content");
+	ret = base32hex_decode(out, ret, out2, BUF_LEN);
+	cmp_ok(ret, "==", in_len, "1. test vector - DEC output length");
+	ok(memcmp(out2, in, ret) == 0, "1. test vector - DEC output content");
+
+	// 2. test vector -> ENC -> DEC
+	strcpy((char *)in, "f");
+	in_len = strlen((char *)in);
+	strcpy((char *)ref, "CO======");
+	ref_len = strlen((char *)ref);
+	ret = base32hex_encode(in, in_len, out, BUF_LEN);
+	cmp_ok(ret, "==", ref_len, "2. test vector - ENC output length");
+	ok(memcmp(out, ref, ret) == 0, "2. test vector - ENC output content");
+	ret = base32hex_decode(out, ret, out2, BUF_LEN);
+	cmp_ok(ret, "==", in_len, "2. test vector - DEC output length");
+	ok(memcmp(out2, in, ret) == 0, "2. test vector - DEC output content");
+
+	// 3. test vector -> ENC -> DEC
+	strcpy((char *)in, "fo");
+	in_len = strlen((char *)in);
+	strcpy((char *)ref, "CPNG====");
+	ref_len = strlen((char *)ref);
+	ret = base32hex_encode(in, in_len, out, BUF_LEN);
+	cmp_ok(ret, "==", ref_len, "3. test vector - ENC output length");
+	ok(memcmp(out, ref, ret) == 0, "3. test vector - ENC output content");
+	ret = base32hex_decode(out, ret, out2, BUF_LEN);
+	cmp_ok(ret, "==", in_len, "3. test vector - DEC output length");
+	ok(memcmp(out2, in, ret) == 0, "3. test vector - DEC output content");
+
+	// 4. test vector -> ENC -> DEC
+	strcpy((char *)in, "foo");
+	in_len = strlen((char *)in);
+	strcpy((char *)ref, "CPNMU===");
+	ref_len = strlen((char *)ref);
+	ret = base32hex_encode(in, in_len, out, BUF_LEN);
+	cmp_ok(ret, "==", ref_len, "4. test vector - ENC output length");
+	ok(memcmp(out, ref, ret) == 0, "4. test vector - ENC output content");
+	ret = base32hex_decode(out, ret, out2, BUF_LEN);
+	cmp_ok(ret, "==", in_len, "4. test vector - DEC output length");
+	ok(memcmp(out2, in, ret) == 0, "4. test vector - DEC output content");
+
+	// 5. test vector -> ENC -> DEC
+	strcpy((char *)in, "foob");
+	in_len = strlen((char *)in);
+	strcpy((char *)ref, "CPNMUOG=");
+	ref_len = strlen((char *)ref);
+	ret = base32hex_encode(in, in_len, out, BUF_LEN);
+	cmp_ok(ret, "==", ref_len, "5. test vector - ENC output length");
+	ok(memcmp(out, ref, ret) == 0, "5. test vector - ENC output content");
+	ret = base32hex_decode(out, ret, out2, BUF_LEN);
+	cmp_ok(ret, "==", in_len, "5. test vector - DEC output length");
+	ok(memcmp(out2, in, ret) == 0, "5. test vector - DEC output content");
+
+	// 6. test vector -> ENC -> DEC
+	strcpy((char *)in, "fooba");
+	in_len = strlen((char *)in);
+	strcpy((char *)ref, "CPNMUOJ1");
+	ref_len = strlen((char *)ref);
+	ret = base32hex_encode(in, in_len, out, BUF_LEN);
+	cmp_ok(ret, "==", ref_len, "6. test vector - ENC output length");
+	ok(memcmp(out, ref, ret) == 0, "6. test vector - ENC output content");
+	ret = base32hex_decode(out, ret, out2, BUF_LEN);
+	cmp_ok(ret, "==", in_len, "6. test vector - DEC output length");
+	ok(memcmp(out2, in, ret) == 0, "6. test vector - DEC output content");
+
+	// 7. test vector -> ENC -> DEC
+	strcpy((char *)in, "foobar");
+	in_len = strlen((char *)in);
+	strcpy((char *)ref, "CPNMUOJ1E8======");
+	ref_len = strlen((char *)ref);
+	ret = base32hex_encode(in, in_len, out, BUF_LEN);
+	cmp_ok(ret, "==", ref_len, "7. test vector - ENC output length");
+	ok(memcmp(out, ref, ret) == 0, "7. test vector - ENC output content");
+	ret = base32hex_decode(out, ret, out2, BUF_LEN);
+	cmp_ok(ret, "==", in_len, "7. test vector - DEC output length");
+	ok(memcmp(out2, in, ret) == 0, "7. test vector - DEC output content");
+
+	// Bad paddings
+        ret = base32hex_decode((uint8_t *)"AAAAAA==", 8, out, BUF_LEN);
+        cmp_ok(ret, "==", -2, "Bad padding length 2");
+        ret = base32hex_decode((uint8_t *)"AAA=====", 8, out, BUF_LEN);
+        cmp_ok(ret, "==", -2, "Bad padding length 5");
+        ret = base32hex_decode((uint8_t *)"A======", 8, out, BUF_LEN);
+        cmp_ok(ret, "==", -2, "Bad padding length 7");
+        ret = base32hex_decode((uint8_t *)"=======", 8, out, BUF_LEN);
+        cmp_ok(ret, "==", -2, "Bad padding length 8");
+
+	// Bad data length
+        ret = base32hex_decode((uint8_t *)"A", 1, out, BUF_LEN);
+        cmp_ok(ret, "==", -1, "Bad data length 1");
+        ret = base32hex_decode((uint8_t *)"AA", 2, out, BUF_LEN);
+        cmp_ok(ret, "==", -1, "Bad data length 2");
+        ret = base32hex_decode((uint8_t *)"AAA", 3, out, BUF_LEN);
+        cmp_ok(ret, "==", -1, "Bad data length 3");
+        ret = base32hex_decode((uint8_t *)"AAAA", 4, out, BUF_LEN);
+        cmp_ok(ret, "==", -1, "Bad data length 4");
+        ret = base32hex_decode((uint8_t *)"AAAAA", 5, out, BUF_LEN);
+        cmp_ok(ret, "==", -1, "Bad data length 5");
+        ret = base32hex_decode((uint8_t *)"AAAAAA", 6, out, BUF_LEN);
+        cmp_ok(ret, "==", -1, "Bad data length 6");
+        ret = base32hex_decode((uint8_t *)"AAAAAAA", 7, out, BUF_LEN);
+        cmp_ok(ret, "==", -1, "Bad data length 7");
+        ret = base32hex_decode((uint8_t *)"AAAAAAAAA", 9, out, BUF_LEN);
+        cmp_ok(ret, "==", -1, "Bad data length 9");
+
+	// Bad data character
+        ret = base32hex_decode((uint8_t *)"AAAAAAA$", 8, out, BUF_LEN);
+        cmp_ok(ret, "==", -2, "Bad data character dollar");
+        ret = base32hex_decode((uint8_t *)"AAAAAAA ", 8, out, BUF_LEN);
+        cmp_ok(ret, "==", -2, "Bad data character space");
+
+	return 0;
+}
diff --git a/src/tests/common/base32hex_tests.h b/src/tests/common/base32hex_tests.h
new file mode 100644
index 0000000..57d4153
--- /dev/null
+++ b/src/tests/common/base32hex_tests.h
@@ -0,0 +1,25 @@
+/*  Copyright (C) 2011 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _KNOTD_BASE32HEX_TESTS_H_
+#define _KNOTD_BASE32HEX_TESTS_H_
+
+#include "common/libtap/tap_unit.h"
+
+/* Unit API. */
+unit_api base32hex_tests_api;
+
+#endif /* _KNOTD_BASE32HEX_TESTS_H_ */
diff --git a/src/tests/common/base64_tests.c b/src/tests/common/base64_tests.c
new file mode 100644
index 0000000..9453c98
--- /dev/null
+++ b/src/tests/common/base64_tests.c
@@ -0,0 +1,154 @@
+/*  Copyright (C) 2011 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "tests/common/base64_tests.h"
+
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "common/base64.h"
+
+#define BUF_LEN 256
+
+static int base64_tests_count(int argc, char *argv[]);
+static int base64_tests_run(int argc, char *argv[]);
+
+unit_api base64_tests_api = {
+	"Base64 encoding",
+	&base64_tests_count,
+	&base64_tests_run
+};
+
+static int base64_tests_count(int argc, char *argv[])
+{
+	return 36;
+}
+
+static int base64_tests_run(int argc, char *argv[])
+{
+	int32_t  ret;
+	uint8_t  in[BUF_LEN], ref[BUF_LEN], out[BUF_LEN], out2[BUF_LEN];
+	uint32_t in_len, ref_len;
+
+	// 1. test vector -> ENC -> DEC
+	strcpy((char *)in, "");
+	in_len = strlen((char *)in);
+	strcpy((char *)ref, "");
+	ref_len = strlen((char *)ref);
+	ret = base64_encode(in, in_len, out, BUF_LEN);
+	cmp_ok(ret, "==", ref_len, "1. test vector - ENC output length");
+	ok(memcmp(out, ref, ret) == 0, "1. test vector - ENC output content");
+	ret = base64_decode(out, ret, out2, BUF_LEN);
+	cmp_ok(ret, "==", in_len, "1. test vector - DEC output length");
+	ok(memcmp(out2, in, ret) == 0, "1. test vector - DEC output content");
+
+	// 2. test vector -> ENC -> DEC
+	strcpy((char *)in, "f");
+	in_len = strlen((char *)in);
+	strcpy((char *)ref, "Zg==");
+	ref_len = strlen((char *)ref);
+	ret = base64_encode(in, in_len, out, BUF_LEN);
+	cmp_ok(ret, "==", ref_len, "2. test vector - ENC output length");
+	ok(memcmp(out, ref, ret) == 0, "2. test vector - ENC output content");
+	ret = base64_decode(out, ret, out2, BUF_LEN);
+	cmp_ok(ret, "==", in_len, "2. test vector - DEC output length");
+	ok(memcmp(out2, in, ret) == 0, "2. test vector - DEC output content");
+
+	// 3. test vector -> ENC -> DEC
+	strcpy((char *)in, "fo");
+	in_len = strlen((char *)in);
+	strcpy((char *)ref, "Zm8=");
+	ref_len = strlen((char *)ref);
+	ret = base64_encode(in, in_len, out, BUF_LEN);
+	cmp_ok(ret, "==", ref_len, "3. test vector - ENC output length");
+	ok(memcmp(out, ref, ret) == 0, "3. test vector - ENC output content");
+	ret = base64_decode(out, ret, out2, BUF_LEN);
+	cmp_ok(ret, "==", in_len, "3. test vector - DEC output length");
+	ok(memcmp(out2, in, ret) == 0, "3. test vector - DEC output content");
+
+	// 4. test vector -> ENC -> DEC
+	strcpy((char *)in, "foo");
+	in_len = strlen((char *)in);
+	strcpy((char *)ref, "Zm9v");
+	ref_len = strlen((char *)ref);
+	ret = base64_encode(in, in_len, out, BUF_LEN);
+	cmp_ok(ret, "==", ref_len, "4. test vector - ENC output length");
+	ok(memcmp(out, ref, ret) == 0, "4. test vector - ENC output content");
+	ret = base64_decode(out, ret, out2, BUF_LEN);
+	cmp_ok(ret, "==", in_len, "4. test vector - DEC output length");
+	ok(memcmp(out2, in, ret) == 0, "4. test vector - DEC output content");
+
+	// 5. test vector -> ENC -> DEC
+	strcpy((char *)in, "foob");
+	in_len = strlen((char *)in);
+	strcpy((char *)ref, "Zm9vYg==");
+	ref_len = strlen((char *)ref);
+	ret = base64_encode(in, in_len, out, BUF_LEN);
+	cmp_ok(ret, "==", ref_len, "5. test vector - ENC output length");
+	ok(memcmp(out, ref, ret) == 0, "5. test vector - ENC output content");
+	ret = base64_decode(out, ret, out2, BUF_LEN);
+	cmp_ok(ret, "==", in_len, "5. test vector - DEC output length");
+	ok(memcmp(out2, in, ret) == 0, "5. test vector - DEC output content");
+
+	// 6. test vector -> ENC -> DEC
+	strcpy((char *)in, "fooba");
+	in_len = strlen((char *)in);
+	strcpy((char *)ref, "Zm9vYmE=");
+	ref_len = strlen((char *)ref);
+	ret = base64_encode(in, in_len, out, BUF_LEN);
+	cmp_ok(ret, "==", ref_len, "6. test vector - ENC output length");
+	ok(memcmp(out, ref, ret) == 0, "6. test vector - ENC output content");
+	ret = base64_decode(out, ret, out2, BUF_LEN);
+	cmp_ok(ret, "==", in_len, "6. test vector - DEC output length");
+	ok(memcmp(out2, in, ret) == 0, "6. test vector - DEC output content");
+
+	// 7. test vector -> ENC -> DEC
+	strcpy((char *)in, "foobar");
+	in_len = strlen((char *)in);
+	strcpy((char *)ref, "Zm9vYmFy");
+	ref_len = strlen((char *)ref);
+	ret = base64_encode(in, in_len, out, BUF_LEN);
+	cmp_ok(ret, "==", ref_len, "7. test vector - ENC output length");
+	ok(memcmp(out, ref, ret) == 0, "7. test vector - ENC output content");
+	ret = base64_decode(out, ret, out2, BUF_LEN);
+	cmp_ok(ret, "==", in_len, "7. test vector - DEC output length");
+	ok(memcmp(out2, in, ret) == 0, "7. test vector - DEC output content");
+
+	// Bad paddings
+        ret = base64_decode((uint8_t *)"A===", 4, out, BUF_LEN);
+        cmp_ok(ret, "==", -2, "Bad padding length 3");
+        ret = base64_decode((uint8_t *)"====", 4, out, BUF_LEN);
+        cmp_ok(ret, "==", -2, "Bad padding length 4");
+
+	// Bad data length
+        ret = base64_decode((uint8_t *)"A", 1, out, BUF_LEN);
+        cmp_ok(ret, "==", -1, "Bad data length 1");
+        ret = base64_decode((uint8_t *)"AA", 2, out, BUF_LEN);
+        cmp_ok(ret, "==", -1, "Bad data length 2");
+        ret = base64_decode((uint8_t *)"AAA", 3, out, BUF_LEN);
+        cmp_ok(ret, "==", -1, "Bad data length 3");
+        ret = base64_decode((uint8_t *)"AAAAA", 5, out, BUF_LEN);
+        cmp_ok(ret, "==", -1, "Bad data length 5");
+
+	// Bad data character
+        ret = base64_decode((uint8_t *)"AAA$", 4, out, BUF_LEN);
+        cmp_ok(ret, "==", -2, "Bad data character dollar");
+        ret = base64_decode((uint8_t *)"AAA ", 4, out, BUF_LEN);
+        cmp_ok(ret, "==", -2, "Bad data character space");
+
+	return 0;
+}
diff --git a/src/tests/common/base64_tests.h b/src/tests/common/base64_tests.h
new file mode 100644
index 0000000..57a0edc
--- /dev/null
+++ b/src/tests/common/base64_tests.h
@@ -0,0 +1,25 @@
+/*  Copyright (C) 2011 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _KNOTD_BASE64_TESTS_H_
+#define _KNOTD_BASE64_TESTS_H_
+
+#include "common/libtap/tap_unit.h"
+
+/* Unit API. */
+unit_api base64_tests_api;
+
+#endif /* _KNOTD_BASE64_TESTS_H_ */
diff --git a/src/tests/libknot/libknot/response_tests.c b/src/tests/libknot/libknot/response_tests.c
index 9c477c8..834d838 100644
--- a/src/tests/libknot/libknot/response_tests.c
+++ b/src/tests/libknot/libknot/response_tests.c
@@ -77,7 +77,7 @@ static int test_response_init_query()
 	int errors = 0;
 	int lived = 0;
 	lives_ok({
-		if (knot_response_init_from_query(NULL, NULL) !=
+		if (knot_response_init_from_query(NULL, NULL, 1) !=
 		    KNOT_EINVAL) {
 			diag("Calling response_init_query with NULL packet and "
 			     "NULL query did not return KNOT_EINVAL!");
@@ -91,7 +91,7 @@ static int test_response_init_query()
 		                           KNOT_PACKET_PREALLOC_RESPONSE);
 		knot_response_init(response);
 		lived = 0;
-		if (knot_response_init_from_query(response, NULL) !=
+		if (knot_response_init_from_query(response, NULL, 1) !=
 		    KNOT_EINVAL) {
 			diag("Calling response_init_query with NULL query "
 			     "did not return KNOT_EINVAL!");
@@ -100,7 +100,7 @@ static int test_response_init_query()
 		lived = 1;
 		knot_packet_t *query =
 			knot_packet_new(KNOT_PACKET_PREALLOC_QUERY);
-		if (knot_response_init_from_query(NULL, query) !=
+		if (knot_response_init_from_query(NULL, query, 1) !=
 		    KNOT_EINVAL) {
 			diag("Calling response_init_query with NULL response "
 			     "did not return KNOT_EINVAL!");
diff --git a/src/tests/libknot/realdata/libknot/response_tests_realdata.c b/src/tests/libknot/realdata/libknot/response_tests_realdata.c
index 0413238..63961f7 100644
--- a/src/tests/libknot/realdata/libknot/response_tests_realdata.c
+++ b/src/tests/libknot/realdata/libknot/response_tests_realdata.c
@@ -69,7 +69,7 @@ static int test_response_init_from_query(list query_list)
 		assert(query);
 		knot_packet_set_max_size(response, 1024 * 10);
 		if (knot_response_init_from_query(response,
-		                                     query) != KNOT_EOK) {
+		                                  query, 1) != KNOT_EOK) {
 			diag("Could not init response from query!");
 			errors++;
 		}
diff --git a/src/tests/unittests_main.c b/src/tests/unittests_main.c
index 21eae14..17ea3b4 100644
--- a/src/tests/unittests_main.c
+++ b/src/tests/unittests_main.c
@@ -24,6 +24,8 @@
 #include "tests/common/events_tests.h"
 #include "tests/common/acl_tests.h"
 #include "tests/common/fdset_tests.h"
+#include "tests/common/base64_tests.h"
+#include "tests/common/base32hex_tests.h"
 #include "tests/knot/dthreads_tests.h"
 #include "tests/knot/journal_tests.h"
 #include "tests/knot/server_tests.h"
@@ -41,17 +43,19 @@ int main(int argc, char *argv[])
 	// Build test set
 	unit_api *tests[] = {
 		/* Core data structures. */
-		&journal_tests_api,  //! Journal unit
-		&slab_tests_api,     //! SLAB allocator unit
-		&skiplist_tests_api, //! Skip list unit
-		&dthreads_tests_api, //! DThreads testing unit
-		&events_tests_api,   //! Events testing unit
-		&acl_tests_api,      //! ACLs
-		&fdset_tests_api, //! FDSET polling wrapper
+		&journal_tests_api,	//! Journal unit
+		&slab_tests_api,	//! SLAB allocator unit
+		&skiplist_tests_api,	//! Skip list unit
+		&dthreads_tests_api,	//! DThreads testing unit
+		&events_tests_api,	//! Events testing unit
+		&acl_tests_api,		//! ACLs
+		&fdset_tests_api,	//! FDSET polling wrapper
+		&base64_tests_api,	//! Base64 encoding
+		&base32hex_tests_api,	//! Base32hex encoding
 
 		/* Server parts. */
-		&conf_tests_api,     //! Configuration parser tests
-		&server_tests_api,   //! Server unit
+		&conf_tests_api,	//! Configuration parser tests
+		&server_tests_api,	//! Server unit
 		NULL
 	};
 
diff --git a/src/zcompile/parser-util.c b/src/zcompile/parser-util.c
index 955a7b0..4cdb4e3 100644
--- a/src/zcompile/parser-util.c
+++ b/src/zcompile/parser-util.c
@@ -1802,8 +1802,12 @@ uint16_t * zparser_conv_b32(const char *b32)
 	/*!< \todo BLEEDING EYES! */
 	b32_copy[strlen(b32)] = '\0';
 
-	if (!base32hex_decode(b32_copy,
-	                      strlen(b32_copy), (char *)buffer + 1, &i)) {
+	int32_t b32_ret = base32hex_decode((uint8_t *)b32_copy, strlen(b32_copy),
+	                                   buffer + 1, i);
+
+	i = b32_ret;
+
+	if (b32_ret <= 0) {
 		zc_error_prev_line("invalid base32 data");
 		parser->error_occurred = 1;
 	} else {
diff --git a/src/zcompile/zcompile.c b/src/zcompile/zcompile.c
index e2f05e3..636a877 100644
--- a/src/zcompile/zcompile.c
+++ b/src/zcompile/zcompile.c
@@ -270,7 +270,7 @@ dbg_zp_exec_detail(
 		if (knot_node_rrset(knot_zone_contents_apex(contents),
 		                      KNOT_RRTYPE_SOA) != NULL) {
 			/* Receiving another SOA. */
-			if (!knot_rrset_compare(current_rrset,
+			if (!knot_rrset_match(current_rrset,
 			    knot_node_rrset(knot_zone_contents_apex(contents),
 			    KNOT_RRTYPE_SOA), KNOT_RRSET_COMPARE_WHOLE)) {
 				return KNOTDZCOMPILE_ESOA;
diff --git a/tests/Makefile b/tests/Makefile
new file mode 100644
index 0000000..bd3e9aa
--- /dev/null
+++ b/tests/Makefile
@@ -0,0 +1,16 @@
+BASE = ../src
+CFLAGS += -std=gnu99 -g -I.. -I$(BASE) -I$(BASE)/libknot -I/usr/local/include 
+
+chkjournal: chkjournal.c $(BASE)/libknotd.la
+	libtool --mode=link $(CC) $(CFLAGS) chkjournal.c $(BASE)/libknotd.la -o chkjournal 
+chkjournal-i386:
+	@echo "!!! Make sure knot is compiled with -fpack-struct=4"
+	@grep -q -- "-fpack-struct=4" $(BASE)/Makefile || exit 1
+	libtool --mode=link $(CC) $(CFLAGS) -fpack-struct=4 chkjournal.c $(BASE)/libknotd.la -o chkjournal-i386 
+chkjournal-amd64:
+	@echo "!!! Make sure knot is compiled with -fpack-struct=8"
+	@grep -q -- "-fpack-struct=8" $(BASE)/Makefile || exit 1
+	libtool --mode=link $(CC) $(CFLAGS) -fpack-struct=8 chkjournal.c $(BASE)/libknotd.la -o chkjournal-amd64 
+clean:
+	rm chkjournal chkjournal-i386 chkjournal-amd64
+
diff --git a/tests/chkjournal.c b/tests/chkjournal.c
new file mode 100644
index 0000000..b429a87
--- /dev/null
+++ b/tests/chkjournal.c
@@ -0,0 +1,541 @@
+/*  Copyright (C) 2011 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+    Usage: chkjournal --help
+
+    How to make:
+      (for this computer):  make chkjournal
+      (for 32bit journals): make chkjournal-i386
+      (for 64bit journal):  make chkjournal-amd64
+      
+   !!! For specific versions, make sure the libknotd.la is compiled
+   with -fpack-struct=4 for 32bit or -fpack-struct=8 for 64bit chkjournal.
+   f.e.:
+     $ cd <knot_root>
+     $ CFLAGS="-fpack-struct=4" ./configure
+     $ make clean && make -j8
+     $ cd tests
+     $ make chkjournal-i386
+ */
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <getopt.h>
+#include <assert.h>
+#include <sys/stat.h>
+
+#ifndef KNOT_RRSET_DEBUG
+#define KNOT_RRSET_DEBUG 1
+#endif
+
+//#define KNOT_RDATA_DEBUG 1
+#include "src/common/log.h"
+#include "src/common/crc.h"
+#include "src/common/errcode.h"
+#include "src/knot/server/journal.h"
+#include "src/knot/server/zones.h"
+#include "src/libknot/updates/changesets.h"
+#include "src/libknot/util/debug.h"
+#include "src/libknot/util/debug.c"
+#include "config.h"
+
+/* Alignment. */
+static size_t ALIGNMENT = 1;
+static inline size_t a(size_t s) {
+	return s + s % ALIGNMENT;
+}
+static size_t PADDING = 4;
+
+/*! \brief Return 'serial_from' part of the key. */
+static inline uint32_t ixfrdb_key_from(uint64_t k)
+{
+	/*      64    32       0
+	 * key = [TO   |   FROM]
+	 * Need: Least significant 32 bits.
+	 */
+	return (uint32_t)(k & ((uint64_t)0x00000000ffffffff));
+}
+
+/*----------------------------------------------------------------------------*/
+
+/*! \brief Return 'serial_to' part of the key. */
+static inline uint32_t ixfrdb_key_to(uint64_t k)
+{
+	/*      64    32       0
+	 * key = [TO   |   FROM]
+	 * Need: Most significant 32 bits.
+	 */
+	return (uint32_t)(k >> (uint64_t)32);
+}
+
+/*----------------------------------------------------------------------------*/
+
+#define MAGIC_LENGTH 7
+
+enum {
+	SHOW = 0,
+	UPDATE,
+	FIXCRC,
+	DUMP,
+	XDUMP
+};
+
+void help(int argc, char **argv)
+{
+	printf("Usage: chkjournal [parameters] <journal_file>\n");
+	printf("Parameters:\n"
+	       " -p, --padding=N    Padding after each node.\n"
+	       " -a, --align=N      Expect journal structures aligned to N bytes.\n"
+	       " -f, --fixcrc       Recompute CRC32.\n"
+	       " -u, --update       Update version to latest.\n"
+	       " -x, --xdump=id     Dump changeset (hexdump).\n"
+	       " -d, --dump=id      Dump changeset (parsed).\n"
+	       " -h, --help         Print help and usage.\n"
+	       );
+}
+
+/* Show. */
+int walkf(journal_t *j, journal_node_t *n) {
+	printf("entry '%zu' flags=0x%hu fpos=%u len=%u\n", n->id, n->flags, n->pos, n->len);
+	return 0;
+}
+
+int show(const char *fname)
+{
+	/* Open journal. */
+	journal_t *j = journal_open(fname, -1, 0, 0);
+	if (j == NULL) {
+		fprintf(stderr, "error: couldn't open journal '%s'\n", fname);
+		return 1;
+	}
+
+	printf("journal: %s max_nodes=%hu queue=%u..%u\n",
+	       fname, j->max_nodes, j->qtail, j->qhead);
+	journal_walk(j, walkf);
+	journal_close(j);
+	return 0;
+}
+
+/* Fix CRC. */
+int fixcrc(const char *fname)
+{
+	int fd = open(fname, O_RDONLY);
+	if (fd < 0) {
+		return 1;
+	}
+	
+	int ret = 1;
+	if (journal_update_crc(fd) == 0) {
+		ret = 0;
+	}
+	
+	close(fd);
+	return ret;
+}
+
+/* Fix file positions. */
+static int FPOSDELTA = 0;
+int walkfix(journal_t *j, journal_node_t *n) {
+	n->pos += FPOSDELTA;
+	journal_update(j, n);
+	return 0;
+}
+
+int fixfpos(const char *fname, int delta)
+{
+	/* Open journal. */
+	journal_t *j = journal_open(fname, -1, 0, 0);
+	if (j == NULL) {
+		fprintf(stderr, "error: couldn't open journal '%s'\n", fname);
+		return 1;
+	}
+	FPOSDELTA = delta;
+	journal_walk(j, walkfix);
+	journal_close(j);
+	return 0;
+}
+
+/* Update journal file. */
+int update(const char *fname)
+{
+	int fd = open(fname, O_RDONLY);
+	if (fd < 0) {
+		return 1;
+	}
+	
+	/* Check source magic bytes. */
+	int rb = 0;
+	int ret = 0;
+	char buf[4096];
+	char mbytes[MAGIC_LENGTH] = {};
+	read(fd, mbytes, MAGIC_LENGTH);
+	if (memcmp(mbytes, "knot100", MAGIC_LENGTH) == 0) {
+		/* 100 -> 101 +crc after MB. */
+		char *nfname = malloc(strlen(fname) + 4 + 1);
+		assert(nfname != NULL);
+		strncpy(nfname, fname, strlen(fname));
+		strncat(nfname, ".new", 4);
+		int nfd = open(nfname, O_RDWR|O_CREAT|O_TRUNC, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP);
+		const char nmbytes[] = "knot101";
+		if (nfd >= 0) {
+			/* Extend header. */
+			write(nfd, nmbytes, MAGIC_LENGTH);
+			write(nfd, buf, sizeof(crc_t));
+			read(fd, buf, sizeof(uint16_t) * 3);
+			write(nfd, buf, sizeof(uint16_t) * 3);
+			
+			/* Copy nodes. */
+			uint16_t ncount = *((uint16_t*)buf) + 1;
+			printf("Will update %hu nodes.\n", ncount - 1);
+			for (uint16_t i = 0; i < ncount; ++i) {
+				/* Copy id+flags. */
+				read(fd, buf, a(sizeof(uint64_t)+sizeof(uint16_t)));
+				write(nfd, buf, a(sizeof(uint64_t)+sizeof(uint16_t)));
+				read(fd, buf, a(2*sizeof(uint32_t)));
+				*((uint32_t*)buf) += sizeof(crc_t);
+				write(nfd, buf, a(2*sizeof(uint32_t)));
+				/* Copy padding. */
+				read(fd, buf, PADDING);
+				write(nfd, buf, PADDING);
+			}
+			
+			/* Copy remaining. */
+			while((rb = read(fd, buf, sizeof(buf))) > 0) {
+				if (write(nfd, buf, rb) != rb) {
+					ret = 1;
+					break;
+				}
+			}
+			/* Update CRC. */
+			if (ret == 0) {
+				journal_update_crc(nfd);
+			}
+		}
+		
+		/* Replace if success. */
+		close(nfd);
+		close(fd);
+		if (ret == 0) {
+			remove(fname);
+			rename(nfname, fname);
+			printf("Converted journal v1.0.0 -> v1.0.1\n");
+		}
+		free(nfname);
+	} else if (memcmp(mbytes, "knot101", MAGIC_LENGTH) == 0) {
+		/* 101 -> 102, transactions, +uint16 'next' in jnode */
+		char *nfname = malloc(strlen(fname) + 4 + 1);
+		assert(nfname != NULL);
+		strncpy(nfname, fname, strlen(fname));
+		strncat(nfname, ".new", 4);
+		int nfd = open(nfname, O_RDWR|O_CREAT|O_TRUNC, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP);
+		size_t hs102 = (MAGIC_LENGTH + sizeof(crc_t) + sizeof(uint16_t) * 3);
+		const char nmbytes[] = "knot102";
+		
+		if (nfd >= 0) {
+			/* Copy header. */
+			lseek(fd, 0, SEEK_SET);
+			read(fd, buf, hs102);
+			write(nfd, buf, hs102);
+			lseek(nfd, 0, SEEK_SET);
+			write(nfd, nmbytes, MAGIC_LENGTH);
+			
+			/* Read node count. */
+			lseek(fd, MAGIC_LENGTH + sizeof(crc_t), SEEK_SET);
+			uint16_t ncount = 0;
+			read(fd, &ncount, sizeof(uint16_t));
+			printf("Will update %hu nodes.\n", ncount);
+			ncount += 1; /* Free segment. */
+			lseek(fd, hs102, SEEK_SET);
+			lseek(nfd, hs102, SEEK_SET);
+			
+			/* Extend nodes. */
+			/*! \todo Calculate offset from difference of struct size. */
+			for (uint16_t i = 0; i < ncount; ++i) {
+				/* Copy id+flags. */
+				read(fd, buf, a(sizeof(uint64_t)+sizeof(uint16_t)));
+				write(nfd, buf, sizeof(uint64_t)+sizeof(uint16_t));
+				/* Append 'next'. */
+				memset(buf, 0, sizeof(uint16_t));
+				write(nfd, buf, sizeof(uint16_t));
+				
+				/* Copy rest. */
+				read(fd, buf, a(2*sizeof(uint32_t)));
+				//*((uint32_t*)buf) += offs;
+				write(nfd, buf, a(2*sizeof(uint32_t)));
+				/* Copy padding. */
+				read(fd, buf, PADDING);
+				write(nfd, buf, PADDING);
+			}
+			
+			/* Copy remaining. */
+			while((rb = read(fd, buf, sizeof(buf))) > 0) {
+				if (write(nfd, buf, rb) != rb) {
+					ret = 1;
+					break;
+				}
+			}
+			/* Update CRC. */
+			if (ret == 0) {
+				journal_update_crc(nfd);
+			}
+		}
+		
+		/* Replace if success. */
+		close(nfd);
+		close(fd);
+		if (ret == 0) {
+			remove(fname);
+			rename(nfname, fname);
+			printf("Converted journal v1.0.1-> v1.0.2\n");
+		}
+		free(nfname);
+	} else if (memcmp(mbytes, "knot102", MAGIC_LENGTH) == 0) {
+		/* Update magic bytes. */
+		const char nmbytes[] = "knot104";
+		int nfd = open(fname, O_RDWR, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP);
+		lseek(nfd, 0, SEEK_SET);
+		write(nfd, nmbytes, MAGIC_LENGTH);
+		journal_update_crc(nfd);
+		close(nfd);
+		printf("Converted journal v1.0.2-> v.1.0.4\n");
+	} else if (memcmp(mbytes, "knot104", MAGIC_LENGTH) == 0) {
+		/* Update magic bytes and add 4bytes to each journal node. */
+		const char nmbytes[] = "knot105";
+		int nfd = open(fname, O_RDWR, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP);
+		lseek(nfd, 0, SEEK_SET);
+		write(nfd, nmbytes, MAGIC_LENGTH);
+		journal_update_crc(nfd);
+		close(nfd);
+		
+		/* Fix crc. */
+		fixcrc(fname);
+		
+		/* Open as source journal. */
+		journal_t *src = journal_open(fname, 0, 0, 0);
+		assert(src != NULL);
+		
+		/* Recreate as new journal. */
+		char *nfname = malloc(strlen(fname) + 4 + 1);
+		assert(nfname != NULL);
+		strncpy(nfname, fname, strlen(fname));
+		strncat(nfname, ".new", 4);
+		journal_create(nfname, src->max_nodes);
+		journal_t *dst = journal_open(nfname, 0, 0, 0);
+		assert(dst != NULL);
+		
+		/* Convert journal entries, adding dummy flags. */
+		uint32_t flags = 1;
+		size_t i = src->qhead;
+		for(; i != src->qtail; i = (i + 1) % src->max_nodes) {
+			journal_node_t *n = src->nodes + i;
+			char *ibuf = malloc(n->len + sizeof(uint32_t));
+			memset(ibuf, &flags, sizeof(uint32_t));
+			journal_read(src, n->id, NULL, ibuf + sizeof(uint32_t));
+			journal_write(dst, n->id, ibuf, n->len + sizeof(uint32_t));
+			free(ibuf);
+		}
+		journal_close(src);
+		journal_close(dst);
+		
+		/* Switch journals. */
+		remove(fname);
+		rename(nfname, fname);
+		free(nfname);
+		printf("Converted journal v1.0.4-> v.1.0.5\n");
+	} else {
+		close(fd);
+	}
+	
+	
+	return ret;
+}
+
+/* Hexdump. */
+int xdump(const char *fname, uint64_t id)
+{
+	/* Open journal. */
+	journal_t *j = journal_open(fname, -1, 0, 0);
+	if (j == NULL) {
+		fprintf(stderr, "error: couldn't open journal '%s'\n", fname);
+		return 1;
+	}
+	
+	int ret = 1;
+	journal_node_t *n = NULL;
+	journal_fetch(j, id, NULL, &n);
+	if (n != NULL) {
+		char *buf = malloc(n->len);
+		assert(buf != NULL);
+		journal_read(j, id, NULL, buf);
+		size_t rf = 0;
+		while(rf < n->len) {
+			if (rf % 16 == 0) printf("\n%08lx |", (unsigned long)rf);
+			printf(" %02x", (unsigned)buf[rf] & 0xffU);
+			++rf;
+		}
+		printf("\n");
+		printf("-- index %llu fpos=%u length=%u\n",
+		       (unsigned long long)id, n->pos, n->len);
+		free(buf);
+		ret = 0;
+	}
+	
+	journal_close(j);
+	return ret;
+}
+
+/* Hexdump. */
+int dump(const char *fname, uint64_t id)
+{
+	/* Open journal. */
+	journal_t *j = journal_open(fname, -1, 0, 0);
+	if (j == NULL) {
+		fprintf(stderr, "error: couldn't open journal '%s'\n", fname);
+		return 1;
+	}
+	
+	journal_node_t *n = NULL;
+	journal_fetch(j, id, NULL, &n);
+	if (n == NULL) {
+		journal_close(j);
+		return 1;
+	}
+	
+	/* Reserve and read changeset. */
+	knot_changesets_t* chsets = malloc(sizeof(knot_changesets_t));
+	assert(chsets != NULL);
+	memset(chsets, 0, sizeof(knot_changesets_t));
+	chsets->count = 1;
+	knot_changesets_check_size(chsets);
+	assert(chsets->sets != NULL);
+	knot_changeset_t *chs = chsets->sets;
+	memset(chs, 0, sizeof(knot_changeset_t));
+	chs->serial_from = ixfrdb_key_from(n->id);
+	chs->serial_to = ixfrdb_key_to(n->id);
+	chs->data = malloc(n->len);
+	assert(chs->data != NULL);
+	journal_read(j, n->id, NULL, chs->data);
+	chs->size = chs->allocated = n->len;
+	
+	/* Unpack */
+	int ks = zones_changesets_from_binary(chsets);
+	printf("=== index %llu fpos=%u length=%u\n",
+	       (unsigned long long)id, n->pos, n->len);
+	
+	/* TODO: dump wireformat? */
+	printf("--- %zu records\n", chs->remove_count);
+	for (unsigned i = 0; i < chs->remove_count; ++i) {
+		knot_rrset_dump(chs->remove[i], 1);
+	}
+	printf("+++ %zu records\n", chs->add_count);
+	for (unsigned i = 0; i < chs->add_count; ++i) {
+		knot_rrset_dump(chs->add[i], 1);
+	}
+	printf("=== index %llu fpos=%u length=%u\n",
+	       (unsigned long long)id, n->pos, n->len);
+
+	/* Close. */
+	//knot_free_changesets(&chsets);
+	journal_close(j);
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	/* Long options. */
+	struct option opts[] = {
+		{"padding",required_argument, 0, 'p'},
+		{"align",  required_argument, 0, 'a'},
+		{"fixcrc", no_argument,       0, 'f'},
+		{"update", no_argument,       0, 'u'},
+	        {"dump",   required_argument, 0, 'd'},
+	        {"xdump",  required_argument, 0, 'x'},
+		{"help",   no_argument,       0, 'h'},
+		{0, 0, 0, 0}
+	};
+	
+	int c = 0, li = 0;
+	int action = SHOW;
+	uint64_t dump_id = 0;
+	while ((c = getopt_long(argc, argv, "p:a:fuhd:x:", opts, &li)) != -1) {
+		switch (c)
+		{
+		case 'p':
+			PADDING = strtoull(optarg, NULL, 10);
+			break;
+		case 'a':
+			ALIGNMENT = strtoull(optarg, NULL, 10);
+			break;
+		case 'f':
+			action = FIXCRC;
+			break;
+		case 'u':
+			action = UPDATE;
+			break;
+		case 'd':
+			action = DUMP;
+			dump_id = strtoull(optarg, NULL, 10);
+			break;
+		case 'x':
+			action = XDUMP;
+			dump_id = strtoull(optarg, NULL, 10);
+			break;
+		case 'h':
+		case '?':
+		default:
+			help(argc, argv);
+			return 1;
+		}
+	}
+	
+	/* Check if there's at least one remaining non-option. */
+	if (argc - optind < 1) {
+		help(argc, argv);
+		return 1;
+	}
+	const char *fname = argv[optind];
+	
+	/* Init log. */
+	log_init();
+	log_levels_set(LOGT_SYSLOG, LOG_ANY, 0);
+	log_levels_set(LOGT_STDERR, LOG_ANY, 0);
+	log_levels_set(LOGT_STDOUT, LOG_ANY, ~0);
+	
+	/* Execute operation. */
+	int ret = 0;
+	switch(action) {
+	case SHOW:
+		ret = show(fname);
+		break;
+	case UPDATE:
+		ret = update(fname);
+		break;
+	case FIXCRC:
+		ret = fixcrc(fname);
+		break;
+	case DUMP:
+		ret = dump(fname, dump_id);
+		break;
+	case XDUMP:
+		ret = xdump(fname, dump_id);
+		break;
+	default:
+		fprintf(stderr, "Unsupported operation.\n");
+		break;
+	}
+	
+	return ret;
+}
author	Ondřej Surý <ondrej@sury.org>	2013-02-18 12:38:51 +0100
committer	Ondřej Surý <ondrej@sury.org>	2013-02-18 12:38:51 +0100
commit	2729227efaac366293e70770b6e82e7e775a2605 (patch)
tree	c93797ba617a3e0b0e6fcee14cc0ea5a13b37fcc
parent	818bb653bebc90f28ea74a14eb1972fbcd172972 (diff)
download	knot-2729227efaac366293e70770b6e82e7e775a2605.tar.gz