dynamic loading of database backends. See: http://pkgs.fedoraproject.org/cgit/bind.git/tree/bind-96-dyndb.patch

Signed-off-by: Adam Tkac <atkac@redhat.com>
Signed-off-by: LaMont Jones <lamont@debian.org>
Addresses-Debian-Bug: #722669

10 files changed, 566 insertions, 3 deletions

diff --git a/bin/named/main.c b/bin/named/main.c
index 45aa1af3..ec5838ca 100644
--- a/bin/named/main.c
+++ b/bin/named/main.c
@@ -45,6 +45,7 @@
 #include <isccc/result.h>
 
 #include <dns/dispatch.h>
+#include <dns/dynamic_db.h>
 #include <dns/name.h>
 #include <dns/result.h>
 #include <dns/view.h>
diff --git a/bin/named/server.c b/bin/named/server.c
index 417f8a5b..bbc85c30 100644
--- a/bin/named/server.c
+++ b/bin/named/server.c
@@ -63,6 +63,7 @@
 #include <dns/db.h>
 #include <dns/dispatch.h>
 #include <dns/dlz.h>
+#include <dns/dynamic_db.h>
 #include <dns/dns64.h>
 #include <dns/forward.h>
 #include <dns/journal.h>
@@ -1245,6 +1246,72 @@ configure_peer(const cfg_obj_t *cpeer, isc_mem_t *mctx, dns_peer_t **peerp) {
 }
 
 static isc_result_t
+configure_dynamic_db(const cfg_obj_t *dynamic_db, isc_mem_t *mctx,
+		     const dns_dyndb_arguments_t *dyndb_args)
+{
+	isc_result_t result;
+	const cfg_obj_t *obj;
+	const cfg_obj_t *options;
+	const cfg_listelt_t *element;
+	const char *name;
+	const char *libname;
+	const char **argv = NULL;
+	unsigned int i;
+	unsigned int len;
+
+	/* Get the name of the database. */
+	obj = cfg_tuple_get(dynamic_db, "name");
+	name = cfg_obj_asstring(obj);
+
+	/* Get options. */
+	options = cfg_tuple_get(dynamic_db, "options");
+
+	/* Get library name. */
+	obj = NULL;
+	CHECK(cfg_map_get(options, "library", &obj));
+	libname = cfg_obj_asstring(obj);
+
+	/* Create a list of arguments. */
+	obj = NULL;
+	result = cfg_map_get(options, "arg", &obj);
+	if (result == ISC_R_NOTFOUND)
+		len = 0;
+	else if (result == ISC_R_SUCCESS)
+		len = cfg_list_length(obj, isc_boolean_false);
+	else
+		goto cleanup;
+
+	/* Account for the last terminating NULL. */
+	len++;
+
+	argv = isc_mem_allocate(mctx, len * sizeof(const char *));
+	if (argv == NULL) {
+		result = ISC_R_NOMEMORY;
+		goto cleanup;
+	}
+	for (element = cfg_list_first(obj), i = 0;
+	     element != NULL;
+	     element = cfg_list_next(element), i++)
+	{
+		REQUIRE(i < len);
+
+		obj = cfg_listelt_value(element);
+		argv[i] = cfg_obj_asstring(obj);
+	}
+	REQUIRE(i < len);
+	argv[i] = NULL;
+
+	CHECK(dns_dynamic_db_load(libname, name, mctx, argv, dyndb_args));
+
+cleanup:
+	if (argv != NULL)
+		isc_mem_free(mctx, argv);
+
+	return result;
+}
+
+
+static isc_result_t
 disable_algorithms(const cfg_obj_t *disabled, dns_resolver_t *resolver) {
 	isc_result_t result;
 	const cfg_obj_t *algorithms;
@@ -2060,6 +2127,7 @@ configure_view(dns_view_t *view, cfg_obj_t *config, cfg_obj_t *vconfig,
 	const cfg_obj_t *dlz;
 	unsigned int dlzargc;
 	char **dlzargv;
+	const cfg_obj_t *dynamic_db_list;
 	const cfg_obj_t *disabled;
 	const cfg_obj_t *obj;
 	const cfg_listelt_t *element;
@@ -3265,6 +3333,37 @@ configure_view(dns_view_t *view, cfg_obj_t *config, cfg_obj_t *vconfig,
 		dns_view_setrootdelonly(view, ISC_FALSE);
 
 	/*
+	 * Configure dynamic databases.
+	 */
+	dynamic_db_list = NULL;
+	if (voptions != NULL)
+		(void)cfg_map_get(voptions, "dynamic-db", &dynamic_db_list);
+	else
+		(void)cfg_map_get(config, "dynamic-db", &dynamic_db_list);
+	element = cfg_list_first(dynamic_db_list);
+	if (element != NULL) {
+		dns_dyndb_arguments_t *args;
+
+		args = dns_dyndb_arguments_create(mctx);
+		if (args == NULL) {
+			result = ISC_R_NOMEMORY;
+			goto cleanup;
+		}
+		dns_dyndb_set_view(args, view);
+		dns_dyndb_set_zonemgr(args, ns_g_server->zonemgr);
+		dns_dyndb_set_task(args, ns_g_server->task);
+		dns_dyndb_set_timermgr(args, ns_g_timermgr);
+		while (element != NULL) {
+			obj = cfg_listelt_value(element);
+			CHECK(configure_dynamic_db(obj, mctx, args));
+		
+			element = cfg_list_next(element);
+		}
+
+		dns_dyndb_arguments_destroy(mctx, args);
+	}
+
+	/*
 	 * Setup automatic empty zones.  If recursion is off then
 	 * they are disabled by default.
 	 */
@@ -4918,6 +5017,7 @@ load_configuration(const char *filename, ns_server_t *server,
 		cfg_aclconfctx_detach(&ns_g_aclconfctx);
 	CHECK(cfg_aclconfctx_create(ns_g_mctx, &ns_g_aclconfctx));
 
+	dns_dynamic_db_cleanup(ISC_FALSE);
 	/*
 	 * Parse the global default pseudo-config file.
 	 */
@@ -6047,6 +6147,8 @@ shutdown_server(isc_task_t *task, isc_event_t *event) {
 			dns_view_detach(&view);
 	}
 
+	dns_dynamic_db_cleanup(ISC_TRUE);
+
 	while ((nsc = ISC_LIST_HEAD(server->cachelist)) != NULL) {
 		ISC_LIST_UNLINK(server->cachelist, nsc, link);
 		dns_cache_detach(&nsc->cache);
diff --git a/lib/dns/Makefile.in b/lib/dns/Makefile.in
index c0f7b442..5bf850ae 100644
--- a/lib/dns/Makefile.in
+++ b/lib/dns/Makefile.in
@@ -62,7 +62,7 @@ DNSOBJS =	acache.@O@ acl.@O@ adb.@O@ byaddr.@O@ \
 		cache.@O@ callbacks.@O@ clientinfo.@O@ compress.@O@ \
 		db.@O@ dbiterator.@O@ dbtable.@O@ diff.@O@ dispatch.@O@ \
 		dlz.@O@ dns64.@O@ dnssec.@O@ ds.@O@ forward.@O@ iptable.@O@ \
-		journal.@O@ keydata.@O@ keytable.@O@ \
+		dynamic_db.@O@ journal.@O@ keydata.@O@ keytable.@O@ \
 		lib.@O@ log.@O@ lookup.@O@ \
 		master.@O@ masterdump.@O@ message.@O@ \
 		name.@O@ ncache.@O@ nsec.@O@ nsec3.@O@ order.@O@ peer.@O@ \
@@ -92,7 +92,7 @@ DNSSRCS =	acache.c acl.c adb.c byaddr.c \
 		cache.c callbacks.c clientinfo.c compress.c \
 		db.c dbiterator.c dbtable.c diff.c dispatch.c \
 		dlz.c dns64.c dnssec.c ds.c forward.c iptable.c journal.c \
-		keydata.c keytable.c lib.c log.c lookup.c \
+		dynamic_db.c keydata.c keytable.c lib.c log.c lookup.c \
 		master.c masterdump.c message.c \
 		name.c ncache.c nsec.c nsec3.c order.c peer.c portlist.c \
 		rbt.c rbtdb.c rbtdb64.c rcode.c rdata.c rdatalist.c \
@@ -125,6 +125,11 @@ version.@O@: version.c
 		-DLIBAGE=${LIBAGE} \
 		-c ${srcdir}/version.c
 
+dynamic_db.@O@: dynamic_db.c
+	${LIBTOOL_MODE_COMPILE} ${CC} ${ALL_CFLAGS} \
+	-DDYNDB_LIBDIR=\"@libdir@/bind/\" \
+	-c ${srcdir}/dynamic_db.c
+
 libdns.@SA@: ${OBJS}
 	${AR} ${ARFLAGS} $@ ${OBJS}
 	${RANLIB} $@
diff --git a/lib/dns/dynamic_db.c b/lib/dns/dynamic_db.c
new file mode 100644
index 00000000..bf831617
--- /dev/null
+++ b/lib/dns/dynamic_db.c
@@ -0,0 +1,366 @@
+/*
+ * Copyright (C) 2008-2011  Red Hat, Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND Red Hat DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS.  IN NO EVENT SHALL Red Hat BE LIABLE FOR ANY SPECIAL, DIRECT,
+ * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+ * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+
+#include <config.h>
+
+#include <isc/buffer.h>
+#include <isc/mem.h>
+#include <isc/mutex.h>
+#include <isc/once.h>
+#include <isc/result.h>
+#include <isc/region.h>
+#include <isc/task.h>
+#include <isc/types.h>
+#include <isc/util.h>
+
+#include <dns/dynamic_db.h>
+#include <dns/log.h>
+#include <dns/types.h>
+#include <dns/view.h>
+#include <dns/zone.h>
+
+#include <string.h>
+
+#if HAVE_DLFCN_H
+#include <dlfcn.h>
+#endif
+
+#ifndef DYNDB_LIBDIR
+#define DYNDB_LIBDIR ""
+#endif
+
+#define CHECK(op)						\
+	do { result = (op);					\
+		if (result != ISC_R_SUCCESS) goto cleanup;	\
+	} while (0)
+
+
+typedef isc_result_t (*register_func_t)(isc_mem_t *mctx, const char *name,
+		const char * const *argv,
+		const dns_dyndb_arguments_t *dyndb_args);
+typedef void (*destroy_func_t)(void);
+
+typedef struct dyndb_implementation dyndb_implementation_t;
+
+struct dyndb_implementation {
+	isc_mem_t			*mctx;
+	void				*handle;
+	register_func_t			register_function;
+	destroy_func_t			destroy_function;
+	LINK(dyndb_implementation_t)	link;
+};
+
+struct dns_dyndb_arguments {
+	dns_view_t	*view;
+	dns_zonemgr_t	*zmgr;
+	isc_task_t	*task;
+	isc_timermgr_t	*timermgr;
+};
+
+/* List of implementations. Locked by dyndb_lock. */
+static LIST(dyndb_implementation_t) dyndb_implementations;
+/* Locks dyndb_implementations. */
+static isc_mutex_t dyndb_lock;
+static isc_once_t once = ISC_ONCE_INIT;
+
+static void
+dyndb_initialize(void) {
+	RUNTIME_CHECK(isc_mutex_init(&dyndb_lock) == ISC_R_SUCCESS);
+	INIT_LIST(dyndb_implementations);
+}
+
+
+#if HAVE_DLFCN_H
+static isc_result_t
+load_symbol(void *handle, const char *symbol_name, void **symbolp)
+{
+	const char *errmsg;
+	void *symbol;
+
+	REQUIRE(handle != NULL);
+	REQUIRE(symbolp != NULL && *symbolp == NULL);
+
+	symbol = dlsym(handle, symbol_name);
+	if (symbol == NULL) {
+		errmsg = dlerror();
+		if (errmsg == NULL)
+			errmsg = "returned function pointer is NULL";
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+			      DNS_LOGMODULE_DYNDB, ISC_LOG_ERROR,
+			      "failed to lookup symbol %s: %s",
+			      symbol_name, errmsg);
+		return ISC_R_FAILURE;
+	}
+	dlerror();
+
+	*symbolp = symbol;
+
+	return ISC_R_SUCCESS;
+}
+
+static isc_result_t
+load_library(isc_mem_t *mctx, const char *filename, dyndb_implementation_t **impp)
+{
+	isc_result_t result;
+	size_t module_size;
+	isc_buffer_t *module_buf = NULL;
+	isc_region_t module_region;
+	void *handle = NULL;
+	dyndb_implementation_t *imp;
+	register_func_t register_function = NULL;
+	destroy_func_t destroy_function = NULL;
+
+	REQUIRE(impp != NULL && *impp == NULL);
+
+	/* Build up the full path. */
+	module_size = strlen(DYNDB_LIBDIR) + strlen(filename) + 1;
+	CHECK(isc_buffer_allocate(mctx, &module_buf, module_size));
+	isc_buffer_putstr(module_buf, DYNDB_LIBDIR);
+	isc_buffer_putstr(module_buf, filename);
+	isc_buffer_putuint8(module_buf, 0);
+	isc_buffer_region(module_buf, &module_region);
+
+	handle = dlopen((char *)module_region.base, RTLD_LAZY);
+	if (handle == NULL) {
+		isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
+			      DNS_LOGMODULE_DYNDB, ISC_LOG_ERROR,
+			      "failed to dynamically load driver '%s': %s",
+			      filename, dlerror());
+		result = ISC_R_FAILURE;
+		goto cleanup;
+	}
+	dlerror();
+
+	CHECK(load_symbol(handle, "dynamic_driver_init",
+			  (void **)&register_function));
+	CHECK(load_symbol(handle, "dynamic_driver_destroy",
+			  (void **)&destroy_function));
+
+	imp = isc_mem_get(mctx, sizeof(dyndb_implementation_t));
+	if (imp == NULL) {
+		result = ISC_R_NOMEMORY;
+		goto cleanup;
+	}
+
+	imp->mctx = NULL;
+	isc_mem_attach(mctx, &imp->mctx);
+	imp->handle = handle;
+	imp->register_function = register_function;
+	imp->destroy_function = destroy_function;
+	INIT_LINK(imp, link);
+
+	*impp = imp;
+
+cleanup:
+	if (result != ISC_R_SUCCESS && handle != NULL)
+		dlclose(handle);
+	if (module_buf != NULL)
+		isc_buffer_free(&module_buf);
+
+	return result;
+}
+
+static void
+unload_library(dyndb_implementation_t **impp)
+{
+	dyndb_implementation_t *imp;
+
+	REQUIRE(impp != NULL && *impp != NULL);
+
+	imp = *impp;
+
+	isc_mem_putanddetach(&imp->mctx, imp, sizeof(dyndb_implementation_t));
+
+	*impp = NULL;
+}
+
+#else	/* HAVE_DLFCN_H */
+static isc_result_t
+load_library(isc_mem_t *mctx, const char *filename, dyndb_implementation_t **impp)
+{
+	UNUSED(mctx);
+	UNUSED(filename);
+	UNUSED(impp);
+
+	isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_DYNDB,
+		      ISC_LOG_ERROR,
+		      "dynamic database support is not implemented")
+
+	return ISC_R_NOTIMPLEMENTED;
+}
+
+static void
+unload_library(dyndb_implementation_t **impp)
+{
+	dyndb_implementation_t *imp;
+
+	REQUIRE(impp != NULL && *impp != NULL);
+
+	imp = *impp;
+
+	isc_mem_putanddetach(&imp->mctx, imp, sizeof(dyndb_implementation_t));
+
+	*impp = NULL;
+}
+#endif	/* HAVE_DLFCN_H */
+
+isc_result_t
+dns_dynamic_db_load(const char *libname, const char *name, isc_mem_t *mctx,
+		    const char * const *argv,
+		    const dns_dyndb_arguments_t *dyndb_args)
+{
+	isc_result_t result;
+	dyndb_implementation_t *implementation = NULL;
+
+	RUNTIME_CHECK(isc_once_do(&once, dyndb_initialize) == ISC_R_SUCCESS);
+
+	CHECK(load_library(mctx, libname, &implementation));
+	CHECK(implementation->register_function(mctx, name, argv, dyndb_args));
+
+	LOCK(&dyndb_lock);
+	APPEND(dyndb_implementations, implementation, link);
+	UNLOCK(&dyndb_lock);
+
+	return ISC_R_SUCCESS;
+
+cleanup:
+	if (implementation != NULL)
+		unload_library(&implementation);
+
+	return result;
+}
+
+void
+dns_dynamic_db_cleanup(isc_boolean_t exiting)
+{
+	dyndb_implementation_t *elem;
+	dyndb_implementation_t *prev;
+
+	RUNTIME_CHECK(isc_once_do(&once, dyndb_initialize) == ISC_R_SUCCESS);
+
+	LOCK(&dyndb_lock);
+	elem = TAIL(dyndb_implementations);
+	while (elem != NULL) {
+		prev = PREV(elem, link);
+		UNLINK(dyndb_implementations, elem, link);
+		elem->destroy_function();
+		unload_library(&elem);
+		elem = prev;
+	}
+	UNLOCK(&dyndb_lock);
+
+	if (exiting == ISC_TRUE)
+		isc_mutex_destroy(&dyndb_lock);
+}
+
+dns_dyndb_arguments_t *
+dns_dyndb_arguments_create(isc_mem_t *mctx)
+{
+	dns_dyndb_arguments_t *args;
+
+	args = isc_mem_get(mctx, sizeof(*args));
+	if (args != NULL)
+		memset(args, 0, sizeof(*args));
+
+	return args;
+}
+
+void
+dns_dyndb_arguments_destroy(isc_mem_t *mctx, dns_dyndb_arguments_t *args)
+{
+	REQUIRE(args != NULL);
+
+	dns_dyndb_set_view(args, NULL);
+	dns_dyndb_set_zonemgr(args, NULL);
+	dns_dyndb_set_task(args, NULL);
+	dns_dyndb_set_timermgr(args, NULL);
+
+	isc_mem_put(mctx, args, sizeof(*args));
+}
+
+void
+dns_dyndb_set_view(dns_dyndb_arguments_t *args, dns_view_t *view)
+{
+	REQUIRE(args != NULL);
+
+	if (args->view != NULL)
+		dns_view_detach(&args->view);
+	if (view != NULL)
+		dns_view_attach(view, &args->view);
+}
+
+dns_view_t *
+dns_dyndb_get_view(dns_dyndb_arguments_t *args)
+{
+	REQUIRE(args != NULL);
+
+	return args->view;
+}
+
+void
+dns_dyndb_set_zonemgr(dns_dyndb_arguments_t *args, dns_zonemgr_t *zmgr)
+{
+	REQUIRE(args != NULL);
+
+	if (args->zmgr != NULL)
+		dns_zonemgr_detach(&args->zmgr);
+	if (zmgr != NULL)
+		dns_zonemgr_attach(zmgr, &args->zmgr);
+}
+
+dns_zonemgr_t *
+dns_dyndb_get_zonemgr(dns_dyndb_arguments_t *args)
+{
+	REQUIRE(args != NULL);
+
+	return args->zmgr;
+}
+
+void
+dns_dyndb_set_task(dns_dyndb_arguments_t *args, isc_task_t *task)
+{
+	REQUIRE(args != NULL);
+
+	if (args->task != NULL)
+		isc_task_detach(&args->task);
+	if (task != NULL)
+		isc_task_attach(task, &args->task);
+}
+
+isc_task_t *
+dns_dyndb_get_task(dns_dyndb_arguments_t *args)
+{
+	REQUIRE(args != NULL);
+
+	return args->task;
+}
+
+void
+dns_dyndb_set_timermgr(dns_dyndb_arguments_t *args, isc_timermgr_t *timermgr)
+{
+	REQUIRE(args != NULL);
+
+	args->timermgr = timermgr;
+}
+
+isc_timermgr_t *
+dns_dyndb_get_timermgr(dns_dyndb_arguments_t *args)
+{
+	REQUIRE(args != NULL);
+
+	return args->timermgr;
+}
diff --git a/lib/dns/include/dns/Makefile.in b/lib/dns/include/dns/Makefile.in
index f2ca095e..47015381 100644
--- a/lib/dns/include/dns/Makefile.in
+++ b/lib/dns/include/dns/Makefile.in
@@ -22,7 +22,7 @@ top_srcdir =	@top_srcdir@
 @BIND9_VERSION@
 
 HEADERS =	acl.h adb.h byaddr.h cache.h callbacks.h cert.h compress.h \
-		clientinfo.h db.h dbiterator.h dbtable.h diff.h dispatch.h \
+		clientinfo.h db.h dbiterator.h dbtable.h diff.h dispatch.h dynamic_db.h \
 		dlz.h dnssec.h ds.h events.h fixedname.h iptable.h journal.h \
 		keyflags.h keytable.h keyvalues.h lib.h log.h \
 		master.h masterdump.h message.h name.h ncache.h nsec.h \
diff --git a/lib/dns/include/dns/dynamic_db.h b/lib/dns/include/dns/dynamic_db.h
new file mode 100644
index 00000000..673ad4bc
--- /dev/null
+++ b/lib/dns/include/dns/dynamic_db.h
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2008-2011  Red Hat, Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND Red Hat DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS.  IN NO EVENT SHALL Red Hat BE LIABLE FOR ANY SPECIAL, DIRECT,
+ * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+ * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+
+#ifndef DYNAMIC_DB_H
+#define DYNAMIC_DB_H
+
+#include <isc/types.h>
+
+#include <dns/types.h>
+
+/*
+ * TODO:
+ * Reformat the prototypes.
+ * Add annotated comments.
+ */
+
+isc_result_t dns_dynamic_db_load(const char *libname, const char *name,
+				 isc_mem_t *mctx, const char * const *argv,
+				 const dns_dyndb_arguments_t *dyndb_args);
+
+void dns_dynamic_db_cleanup(isc_boolean_t exiting);
+
+dns_dyndb_arguments_t *dns_dyndb_arguments_create(isc_mem_t *mctx);
+void dns_dyndb_arguments_destroy(isc_mem_t *mctx, dns_dyndb_arguments_t *args);
+
+void dns_dyndb_set_view(dns_dyndb_arguments_t *args, dns_view_t *view);
+dns_view_t *dns_dyndb_get_view(dns_dyndb_arguments_t *args);
+void dns_dyndb_set_zonemgr(dns_dyndb_arguments_t *args, dns_zonemgr_t *zmgr);
+dns_zonemgr_t *dns_dyndb_get_zonemgr(dns_dyndb_arguments_t *args);
+void dns_dyndb_set_task(dns_dyndb_arguments_t *args, isc_task_t *task);
+isc_task_t *dns_dyndb_get_task(dns_dyndb_arguments_t *args);
+void dns_dyndb_set_timermgr(dns_dyndb_arguments_t *args,
+			    isc_timermgr_t *timermgr);
+isc_timermgr_t *dns_dyndb_get_timermgr(dns_dyndb_arguments_t *args);
+
+#endif
diff --git a/lib/dns/include/dns/log.h b/lib/dns/include/dns/log.h
index e8c8c105..a3b7e5a7 100644
--- a/lib/dns/include/dns/log.h
+++ b/lib/dns/include/dns/log.h
@@ -77,6 +77,7 @@ LIBDNS_EXTERNAL_DATA extern isc_logmodule_t dns_modules[];
 #define DNS_LOGMODULE_DLZ		(&dns_modules[26])
 #define DNS_LOGMODULE_DNSSEC		(&dns_modules[27])
 #define DNS_LOGMODULE_CRYPTO		(&dns_modules[28])
+#define DNS_LOGMODULE_DYNDB		(&dns_modules[29])
 
 ISC_LANG_BEGINDECLS
 
diff --git a/lib/dns/include/dns/types.h b/lib/dns/include/dns/types.h
index 76167c2f..f5e39d45 100644
--- a/lib/dns/include/dns/types.h
+++ b/lib/dns/include/dns/types.h
@@ -60,6 +60,7 @@ typedef struct dns_dbtable			dns_dbtable_t;
 typedef void					dns_dbversion_t;
 typedef struct dns_dlzimplementation		dns_dlzimplementation_t;
 typedef struct dns_dlzdb			dns_dlzdb_t;
+typedef struct dns_dyndb_arguments		dns_dyndb_arguments_t;
 typedef struct dns_sdlzimplementation		dns_sdlzimplementation_t;
 typedef struct dns_decompress			dns_decompress_t;
 typedef struct dns_dispatch			dns_dispatch_t;
diff --git a/lib/dns/log.c b/lib/dns/log.c
index 75e0d79b..b5c8b057 100644
--- a/lib/dns/log.c
+++ b/lib/dns/log.c
@@ -83,6 +83,7 @@ LIBDNS_EXTERNAL_DATA isc_logmodule_t dns_modules[] = {
 	{ "dns/dlz",		0 },
 	{ "dns/dnssec",		0 },
 	{ "dns/crypto",		0 },
+	{ "dns/dynamic_db",	0 },
 	{ NULL, 		0 }
 };
 
diff --git a/lib/isccfg/namedconf.c b/lib/isccfg/namedconf.c
index 08d8e45b..e5bd225f 100644
--- a/lib/isccfg/namedconf.c
+++ b/lib/isccfg/namedconf.c
@@ -92,6 +92,7 @@ static cfg_type_t cfg_type_controls;
 static cfg_type_t cfg_type_controls_sockaddr;
 static cfg_type_t cfg_type_destinationlist;
 static cfg_type_t cfg_type_dialuptype;
+static cfg_type_t cfg_type_dynamic_db;
 static cfg_type_t cfg_type_ixfrdifftype;
 static cfg_type_t cfg_type_key;
 static cfg_type_t cfg_type_logfile;
@@ -897,6 +898,7 @@ namedconf_or_view_clauses[] = {
 	{ "zone", &cfg_type_zone, CFG_CLAUSEFLAG_MULTI },
 	/* only 1 DLZ per view allowed */
 	{ "dlz", &cfg_type_dynamically_loadable_zones, 0 },
+	{ "dynamic-db", &cfg_type_dynamic_db, CFG_CLAUSEFLAG_MULTI },
 	{ "server", &cfg_type_server, CFG_CLAUSEFLAG_MULTI },
 	{ "trusted-keys", &cfg_type_dnsseckeys, CFG_CLAUSEFLAG_MULTI },
 	{ "managed-keys", &cfg_type_managedkeys, CFG_CLAUSEFLAG_MULTI },
@@ -2047,6 +2049,40 @@ static cfg_type_t cfg_type_dialuptype = {
 	&cfg_rep_string, dialup_enums
 };
 
+/*
+ * Dynamic database clauses.
+ */
+
+static cfg_clausedef_t
+dynamic_db_clauses[] = {
+	{ "library", &cfg_type_qstring, 0 },
+	{ "arg", &cfg_type_qstring, CFG_CLAUSEFLAG_MULTI },
+	{ NULL, NULL, 0 }
+};
+
+static cfg_clausedef_t *
+dynamic_db_clausesets[] = {
+	dynamic_db_clauses,
+	NULL
+};
+
+static cfg_type_t cfg_type_dynamic_db_opts = {
+	"dynamically_loadable_zones_opts", cfg_parse_map,
+	cfg_print_map, cfg_doc_map, &cfg_rep_map,
+	dynamic_db_clausesets
+};
+
+static cfg_tuplefielddef_t dynamic_db_fields[] = {
+	{ "name", &cfg_type_astring, 0 },
+	{ "options", &cfg_type_dynamic_db_opts, 0 },
+	{ NULL, NULL, 0 }
+};
+
+static cfg_type_t cfg_type_dynamic_db = {
+	"dynamic_db", cfg_parse_tuple, cfg_print_tuple, cfg_doc_tuple,
+	&cfg_rep_tuple, dynamic_db_fields
+};
+
 static const char *notify_enums[] = { "explicit", "master-only", NULL };
 static isc_result_t
 parse_notify_type(cfg_parser_t *pctx, const cfg_type_t *type, cfg_obj_t **ret) {