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diff --git a/usr/src/man/man1m/snoop.1m b/usr/src/man/man1m/snoop.1m new file mode 100644 index 0000000..ca969e2 --- /dev/null +++ b/usr/src/man/man1m/snoop.1m @@ -0,0 +1,1182 @@ +'\" te +.\" Copyright (C) 2009, Sun Microsystems, Inc. All Rights Reserved +.\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License"). You may not use this file except in compliance with the License. +.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing. See the License for the specific language governing permissions and limitations under the License. +.\" When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE. If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner] +.TH SNOOP 1M "Feb 18, 2009" +.SH NAME +snoop \- capture and inspect network packets +.SH SYNOPSIS +.LP +.nf +\fBsnoop\fR [\fB-aqrCDINPSvV\fR] [\fB-t\fR [r | a | d]] [\fB-c\fR \fImaxcount\fR] + [\fB-d\fR \fIdevice\fR] [\fB-i\fR \fIfilename\fR] [\fB-n\fR \fIfilename\fR] [\fB-o\fR \fIfilename\fR] + [\fB-p\fR \fIfirst\fR [, \fIlast\fR]] [\fB-s\fR \fIsnaplen\fR] [\fB-x\fR \fIoffset\fR [, \fIlength\fR]] + [\fIexpression\fR] +.fi + +.SH DESCRIPTION +.sp +.LP +From a datalink or IP interface, \fBsnoop\fR captures packets and displays +their contents. If the datalink or IP interface is not specified, \fBsnoop\fR +will pick a datalink to use, giving priority to datalinks that have been +plumbed for IP traffic. \fBsnoop\fR uses the \fBpfmod\fR(7M) and +\fBbufmod\fR(7M) STREAMS modules to provide efficient capture of packets from +the network. Captured packets can be displayed as they are received or saved to +a file (which is \fIRFC 1761\fR-compliant) for later inspection. +.sp +.LP +\fBsnoop\fR can display packets in a single-line summary form or in verbose +multi-line forms. In summary form, with the exception of certain VLAN packets, +only the data pertaining to the highest level protocol is displayed. If a +packet has a VLAN header and its VLAN ID is non-zero, then \fBsnoop\fR will +show that the packet is VLAN tagged. For example, an \fBNFS\fR packet will have +only \fBNFS\fR information displayed. Except for VLAN information under the +condition just described, the underlying \fBRPC\fR, \fBUDP\fR, \fBIP\fR, and +Ethernet frame information is suppressed, but can be displayed if either of the +verbose options are chosen. +.sp +.LP +In the absence of a name service, such as LDAP or NIS, \fBsnoop\fR displays +host names as numeric IP addresses. +.sp +.LP +\fBsnoop\fR requires an interactive interface. +.SH OPTIONS +.sp +.ne 2 +.na +\fB\fB-C\fR\fR +.ad +.sp .6 +.RS 4n +List the code generated from the filter expression for either the kernel packet +filter, or \fBsnoop\fR's own filter. +.RE + +.sp +.ne 2 +.na +\fB\fB-D\fR\fR +.ad +.sp .6 +.RS 4n +Display number of packets dropped during capture on the summary line. +.RE + +.sp +.ne 2 +.na +\fB\fB-N\fR\fR +.ad +.sp .6 +.RS 4n +Create an \fBIP\fR address-to-name file from a capture file. This must be set +together with the \fB-i\fR option that names a capture file. The +address-to-name file has the same name as the capture file with \fB\&.names\fR +appended. This file records the \fBIP\fR address to hostname mapping at the +capture site and increases the portability of the capture file. Generate a +\fB\&.names\fR file if the capture file is to be analyzed elsewhere. Packets +are not displayed when this flag is used. +.RE + +.sp +.ne 2 +.na +\fB\fB-I\fR \fIinterface\fR\fR +.ad +.sp .6 +.RS 4n +Capture IP packets from the network using the IP interface specified by +\fIinterface\fR, for example, \fBlo0\fR. The \fBifconfig\fR(1M) command can be +used to list available IP interfaces. The \fB-I\fR and \fB-d\fR options are +mutually exclusive. +.RE + +.sp +.ne 2 +.na +\fB\fB-P\fR\fR +.ad +.sp .6 +.RS 4n +Capture packets in non-promiscuous mode. Only broadcast, multicast, or packets +addressed to the host machine will be seen. +.RE + +.sp +.ne 2 +.na +\fB\fB-S\fR\fR +.ad +.sp .6 +.RS 4n +Display size of the entire link layer frame in bytes on the summary line. +.RE + +.sp +.ne 2 +.na +\fB\fB-V\fR\fR +.ad +.sp .6 +.RS 4n +Verbose summary mode. This is halfway between summary mode and verbose mode in +degree of verbosity. Instead of displaying just the summary line for the +highest level protocol in a packet, it displays a summary line for each +protocol layer in the packet. For instance, for an \fBNFS\fR packet it will +display a line each for the \fBETHER\fR, \fBIP\fR, \fBUDP\fR, \fBRPC\fR and +\fBNFS\fR layers. Verbose summary mode output may be easily piped through +\fBgrep\fR to extract packets of interest. For example, to view only \fBRPC\fR +summary lines, enter the following: \fBexample#\fR \fBsnoop -i rpc.cap -V | +grep RPC\fR +.RE + +.sp +.ne 2 +.na +\fB\fB-a\fR\fR +.ad +.sp .6 +.RS 4n +Listen to packets on \fB/dev/audio\fR (warning: can be noisy). +.RE + +.sp +.ne 2 +.na +\fB\fB-c\fR \fImaxcount\fR\fR +.ad +.sp .6 +.RS 4n +Quit after capturing \fImaxcount\fR packets. Otherwise keep capturing until +there is no disk space left or until interrupted with Control-C. +.RE + +.sp +.ne 2 +.na +\fB\fB-d\fR \fIdatalink\fR\fR +.ad +.sp .6 +.RS 4n +Capture link-layer packets from the network using the DLPI datalink specified +by \fIdatalink\fR, for example, \fBbge0\fR or \fBnet0\fR. The \fBdladm\fR(1M) +\fBshow-link\fR subcommand can be used to list available datalinks. The +\fB-d\fR and \fB-I\fR options are mutually exclusive. +.RE + +.sp +.ne 2 +.na +\fB\fB-i\fR \fIfilename\fR\fR +.ad +.sp .6 +.RS 4n +Display packets previously captured in \fIfilename\fR. Without this option, +\fBsnoop\fR reads packets from the network interface. If a +\fIfilename\fR\fB\&.names\fR file is present, it is automatically loaded into +the \fBsnoop\fR \fBIP\fR address-to-name mapping table (See \fB-N\fR flag). +.RE + +.sp +.ne 2 +.na +\fB\fB-n\fR \fIfilename\fR\fR +.ad +.sp .6 +.RS 4n +Use \fIfilename\fR as an \fBIP\fR address-to-name mapping table. This file must +have the same format as the \fB/etc/hosts\fR file (IP address followed by the +hostname). +.RE + +.sp +.ne 2 +.na +\fB\fB-o\fR \fIfilename\fR\fR +.ad +.sp .6 +.RS 4n +Save captured packets in \fIfilename\fR as they are captured. (This +\fIfilename\fR is referred to as the "capture file".) The format of the capture +file is RFC 1761-compliant. During packet capture, a count of the number of +packets saved in the file is displayed. If you wish just to count packets +without saving to a file, name the file \fB/dev/null\fR. +.RE + +.sp +.ne 2 +.na +\fB\fB-p\fR \fIfirst\fR [ , \fBlast\fR ]\fR +.ad +.sp .6 +.RS 4n +Select one or more packets to be displayed from a capture file. The \fIfirst\fR +packet in the file is packet number 1. +.RE + +.sp +.ne 2 +.na +\fB\fB-q\fR\fR +.ad +.sp .6 +.RS 4n +When capturing network packets into a file, do not display the packet count. +This can improve packet capturing performance. +.RE + +.sp +.ne 2 +.na +\fB\fB-r\fR\fR +.ad +.sp .6 +.RS 4n +Do not resolve the \fBIP\fR address to the symbolic name. This prevents +\fBsnoop\fR from generating network traffic while capturing and displaying +packets. However, if the \fB-n\fR option is used, and an address is found in +the mapping file, its corresponding name will be used. +.RE + +.sp +.ne 2 +.na +\fB\fB-s\fR \fIsnaplen\fR\fR +.ad +.sp .6 +.RS 4n +Truncate each packet after \fIsnaplen\fR bytes. Usually the whole packet is +captured. This option is useful if only certain packet header information is +required. The packet truncation is done within the kernel giving better +utilization of the streams packet buffer. This means less chance of dropped +packets due to buffer overflow during periods of high traffic. It also saves +disk space when capturing large traces to a capture file. To capture only +\fBIP\fR headers (no options) use a \fIsnaplen\fR of 34. For \fBUDP\fR use 42, +and for \fBTCP\fR use 54. You can capture \fBRPC\fR headers with a +\fIsnaplen\fR of 80 bytes. \fBNFS\fR headers can be captured in 120 bytes. +.RE + +.sp +.ne 2 +.na +\fB\fB-t\fR [ \fBr\fR | \fBa\fR | \fBd\fR ]\fR +.ad +.sp .6 +.RS 4n +Time-stamp presentation. Time-stamps are accurate to within 4 microseconds. The +default is for times to be presented in \fBd\fR (delta) format (the time since +receiving the previous packet). Option \fBa\fR (absolute) gives wall-clock +time. Option \fBr\fR (relative) gives time relative to the first packet +displayed. This can be used with the \fB-p\fR option to display time relative +to any selected packet. +.RE + +.sp +.ne 2 +.na +\fB\fB-v\fR\fR +.ad +.sp .6 +.RS 4n +Verbose mode. Print packet headers in lots of detail. This display consumes +many lines per packet and should be used only on selected packets. +.RE + +.sp +.ne 2 +.na +\fB\fB\fR\fB-x\fR\fIoffset\fR [ , \fIlength\fR]\fR +.ad +.sp .6 +.RS 4n +Display packet data in hexadecimal and \fBASCII\fR format. The \fIoffset\fR and +\fIlength\fR values select a portion of the packet to be displayed. To display +the whole packet, use an \fIoffset\fR of 0. If a \fIlength\fR value is not +provided, the rest of the packet is displayed. +.RE + +.SH OPERANDS +.sp +.ne 2 +.na +\fB\fIexpression\fR\fR +.ad +.sp .6 +.RS 4n +Select packets either from the network or from a capture file. Only packets for +which the expression is true will be selected. If no expression is provided it +is assumed to be true. +.sp +Given a filter expression, \fBsnoop\fR generates code for either the kernel +packet filter or for its own internal filter. If capturing packets with the +network interface, code for the kernel packet filter is generated. This filter +is implemented as a streams module, upstream of the buffer module. The buffer +module accumulates packets until it becomes full and passes the packets on to +\fBsnoop\fR. The kernel packet filter is very efficient, since it rejects +unwanted packets in the kernel before they reach the packet buffer or +\fBsnoop\fR. The kernel packet filter has some limitations in its +implementation; it is possible to construct filter expressions that it cannot +handle. In this event, \fBsnoop\fR tries to split the filter and do as much +filtering in the kernel as possible. The remaining filtering is done by the +packet filter for \fBsnoop\fR. The \fB-C\fR flag can be used to view generated +code for either the packet filter for the kernel or the packet filter for +\fBsnoop\fR. If packets are read from a capture file using the \fB-i\fR option, +only the packet filter for \fBsnoop\fR is used. +.sp +A filter \fIexpression\fR consists of a series of one or more boolean +primitives that may be combined with boolean operators (\fBAND\fR, \fBOR\fR, +and \fBNOT\fR). Normal precedence rules for boolean operators apply. Order of +evaluation of these operators may be controlled with parentheses. Since +parentheses and other filter expression characters are known to the shell, it +is often necessary to enclose the filter expression in quotes. Refer to for +information about setting up more efficient filters. +.sp +The primitives are: +.sp +.ne 2 +.na +\fB\fBhost\fR \fIhostname\fR\fR +.ad +.sp .6 +.RS 4n +True if the source or destination address is that of \fBhostname\fR. The +\fIhostname\fR argument may be a literal address. The keyword \fBhost\fR may be +omitted if the name does not conflict with the name of another expression +primitive. For example, \fBpinky\fR selects packets transmitted to or received +from the host \fBpinky\fR, whereas \fBpinky and dinky\fR selects packets +exchanged between hosts \fBpinky AND dinky\fR. +.sp +The type of address used depends on the primitive which precedes the \fBhost\fR +primitive. The possible qualifiers are \fBinet\fR, \fBinet6\fR, \fBether\fR, or +none. These three primitives are discussed below. Having none of the primitives +present is equivalent to "inet host hostname or inet6 host hostname". In other +words, snoop tries to filter on all IP addresses associated with hostname. +.RE + +.sp +.ne 2 +.na +\fB\fIinet\fR or \fIinet6\fR\fR +.ad +.sp .6 +.RS 4n +A qualifier that modifies the \fBhost\fR primitive that follows. If it is +\fIinet\fR, then \fBsnoop\fR tries to filter on all IPv4 addresses returned +from a name lookup. If it is \fIinet6\fR, \fBsnoop\fR tries to filter on all +IPv6 addresses returned from a name lookup. +.RE + +.sp +.ne 2 +.na +\fB\fIipaddr\fR, \fIatalkaddr\fR, or \fIetheraddr\fR\fR +.ad +.sp .6 +.RS 4n +Literal addresses, \fBIP\fR dotted, AppleTalk dotted, and Ethernet colon are +recognized. For example, +.RS +4 +.TP +.ie t \(bu +.el o +"\fB172.16.40.13\fR" matches all packets with that \fBIP\fR +.RE +.RS +4 +.TP +.ie t \(bu +.el o +"\fB2::9255:a00:20ff:fe73:6e35\fR" matches all packets with that IPv6 address +as source or destination; +.RE +.RS +4 +.TP +.ie t \(bu +.el o +"\fB65281.13\fR" matches all packets with that AppleTalk address; +.RE +.RS +4 +.TP +.ie t \(bu +.el o +"\fB8:0:20:f:b1:51\fR" matches all packets with the Ethernet address as source +or destination. +.RE +An Ethernet address beginning with a letter is interpreted as a hostname. To +avoid this, prepend a zero when specifying the address. For example, if the +Ethernet address is \fBaa:0:45:23:52:44\fR, then specify it by add a leading +zero to make it \fB0aa:0:45:23:52:44\fR. +.RE + +.sp +.ne 2 +.na +\fB\fBfrom\fR or \fBsrc\fR\fR +.ad +.sp .6 +.RS 4n +A qualifier that modifies the following \fBhost\fR, \fBnet\fR, \fIipaddr\fR, +\fIatalkaddr\fR, \fIetheraddr\fR, \fBport\fR or \fBrpc\fR primitive to match +just the source address, port, or \fBRPC\fR reply. +.RE + +.sp +.ne 2 +.na +\fB\fBto\fR or \fBdst\fR\fR +.ad +.sp .6 +.RS 4n +A qualifier that modifies the following \fBhost\fR, \fBnet\fR, \fIipaddr\fR, +\fIatalkaddr\fR, \fIetheraddr\fR, \fBport\fR or \fBrpc\fR primitive to match +just the destination address, port, or \fBRPC\fR call. +.RE + +.sp +.ne 2 +.na +\fB\fBether\fR\fR +.ad +.sp .6 +.RS 4n +A qualifier that modifies the following \fBhost\fR primitive to resolve a name +to an Ethernet address. Normally, \fBIP\fR address matching is performed. This +option is not supported on media such as IPoIB (IP over InfiniBand). +.RE + +.sp +.ne 2 +.na +\fB\fBethertype\fR \fInumber\fR\fR +.ad +.sp .6 +.RS 4n +True if the Ethernet type field has value \fInumber\fR. If \fInumber\fR is not +0x8100 (VLAN) and the packet is VLAN tagged, then the expression will match the +encapsulated Ethernet type. +.RE + +.sp +.ne 2 +.na +\fB\fBip\fR, \fBip6\fR, \fBarp\fR, \fBrarp\fR, \fBpppoed\fR, \fBpppoes\fR\fR +.ad +.sp .6 +.RS 4n +True if the packet is of the appropriate ethertype. +.RE + +.sp +.ne 2 +.na +\fB\fBvlan\fR\fR +.ad +.sp .6 +.RS 4n +True if the packet has \fBethertype\fR VLAN and the VLAN ID is not zero. +.RE + +.sp +.ne 2 +.na +\fB\fBvlan-id\fR \fIid\fR\fR +.ad +.sp .6 +.RS 4n +True for packets of ethertype VLAN with the id \fIid\fR. +.RE + +.sp +.ne 2 +.na +\fB\fBpppoe\fR\fR +.ad +.sp .6 +.RS 4n +True if the ethertype of the packet is either \fBpppoed\fR or \fBpppoes\fR. +.RE + +.sp +.ne 2 +.na +\fB\fBbroadcast\fR\fR +.ad +.sp .6 +.RS 4n +True if the packet is a broadcast packet. Equivalent to \fBether[2:4] = +0xffffffff\fR for Ethernet. This option is not supported on media such as IPoIB +(IP over InfiniBand). +.RE + +.sp +.ne 2 +.na +\fB\fBmulticast\fR\fR +.ad +.sp .6 +.RS 4n +True if the packet is a multicast packet. Equivalent to "\fBether[0] & 1 = +1\fR" on Ethernet. This option is not supported on media such as IPoIB (IP over +InfiniBand). +.RE + +.sp +.ne 2 +.na +\fB\fBbootp\fR, \fBdhcp\fR\fR +.ad +.sp .6 +.RS 4n +True if the packet is an unfragmented IPv4 UDP packet with either a source port +of \fBBOOTPS (67)\fR and a destination port of \fBBOOTPC (68)\fR, or a source +port of \fBBOOTPC (68)\fR and a destination of \fBBOOTPS (67)\fR. +.RE + +.sp +.ne 2 +.na +\fB\fBdhcp6\fR\fR +.ad +.sp .6 +.RS 4n +True if the packet is an unfragmented IPv6 UDP packet with either a source port +of \fBDHCPV6-SERVER\fR (547) and a destination port of \fBDHCPV6-CLIENT\fR +(546), or a source port of \fBDHCPV6-CLIENT\fR (546) and a destination of +\fBDHCPV6-SERVER\fR (547). +.RE + +.sp +.ne 2 +.na +\fB\fBapple\fR\fR +.ad +.sp .6 +.RS 4n +True if the packet is an Apple Ethertalk packet. Equivalent to "\fBethertype +0x809b or ethertype 0x80f3\fR". +.RE + +.sp +.ne 2 +.na +\fB\fBdecnet\fR\fR +.ad +.sp .6 +.RS 4n +True if the packet is a \fBDECNET\fR packet. +.RE + +.sp +.ne 2 +.na +\fB\fBgreater\fR \fIlength\fR\fR +.ad +.sp .6 +.RS 4n +True if the packet is longer than \fIlength\fR. +.RE + +.sp +.ne 2 +.na +\fB\fBless\fR \fIlength\fR\fR +.ad +.sp .6 +.RS 4n +True if the packet is shorter than \fIlength\fR. +.RE + +.sp +.ne 2 +.na +\fB\fBudp\fR, \fBtcp\fR, \fBicmp\fR, \fBicmp6\fR, \fBah\fR, \fBesp\fR\fR +.ad +.sp .6 +.RS 4n +True if the \fBIP\fR or IPv6 protocol is of the appropriate type. +.RE + +.sp +.ne 2 +.na +\fB\fBnet\fR \fInet\fR\fR +.ad +.sp .6 +.RS 4n +True if either the \fBIP\fR source or destination address has a network number +of \fInet\fR. The \fBfrom\fR or \fBto\fR qualifier may be used to select +packets for which the network number occurs only in the source or destination +address. +.RE + +.sp +.ne 2 +.na +\fB\fBport\fR \fIport\fR\fR +.ad +.sp .6 +.RS 4n +True if either the source or destination port is \fIport\fR. The \fIport\fR may +be either a port number or name from \fB/etc/services\fR. The \fBtcp\fR or +\fBudp\fR primitives may be used to select \fBTCP\fR or \fBUDP\fR ports only. +The \fBfrom\fR or \fBto\fR qualifier may be used to select packets for which +the \fIport\fR occurs only as the source or destination. +.RE + +.sp +.ne 2 +.na +\fB\fBrpc\fR \fIprog\fR [ , \fIvers\fR [ , \fBproc\fR ] ]\fR +.ad +.sp .6 +.RS 4n +True if the packet is an \fBRPC\fR call or reply packet for the protocol +identified by \fIprog\fR. The \fIprog\fR may be either the name of an \fBRPC\fR +protocol from \fB/etc/rpc\fR or a program number. The \fIvers\fR and \fBproc\fR +may be used to further qualify the program \fIversion\fR and \fIprocedure\fR +number, for example, \fBrpc nfs,2,0\fR selects all calls and replies for the +\fBNFS\fR null procedure. The \fBto\fR or \fBfrom\fR qualifier may be used to +select either call or reply packets only. +.RE + +.sp +.ne 2 +.na +\fB\fBzone\fR \fIzoneid\fR\fR +.ad +.sp .6 +.RS 4n +True if \fIzoneid\fR matches either the source or destination \fIzoneid\fR of a +packet received on an \fBipnet\fR device. +.RE + +.sp +.ne 2 +.na +\fB\fBldap\fR\fR +.ad +.sp .6 +.RS 4n +True if the packet is an \fBLDAP\fR packet on port 389. +.RE + +.sp +.ne 2 +.na +\fB\fBgateway\fR \fIhost\fR\fR +.ad +.sp .6 +.RS 4n +True if the packet used \fIhost\fR as a gateway, that is, the Ethernet source +or destination address was for \fIhost\fR but not the \fBIP\fR address. +Equivalent to "\fBether host\fR \fIhost\fR and not host \fIhost\fR". +.RE + +.sp +.ne 2 +.na +\fB\fBnofrag\fR\fR +.ad +.sp .6 +.RS 4n +True if the packet is unfragmented or is the first in a series of \fBIP\fR +fragments. Equivalent to \fBip[6:2] & 0x1fff = 0\fR. +.RE + +.sp +.ne 2 +.na +\fB\fIexpr\fR \fIrelop\fR \fIexpr\fR\fR +.ad +.sp .6 +.RS 4n +True if the relation holds, where \fIrelop\fR is one of \fB>\fR, \fB<\fR, +\fB>=\fR, \fB<=\fR, \fB=\fR, \fB!=\fR, and \fBexpr\fR is an arithmetic +expression composed of numbers, packet field selectors, the \fBlength\fR +primitive, and arithmetic operators \fB+\fR, \fB\(mi\fR, \fB*\fR, \fB&\fR, +\fB|\fR, \fB^\fR, and \fB%\fR. The arithmetic operators within \fBexpr\fR are +evaluated before the relational operator and normal precedence rules apply +between the arithmetic operators, such as multiplication before addition. +Parentheses may be used to control the order of evaluation. To use the value of +a field in the packet use the following syntax: +.sp +.in +2 +.nf +\fIbase\fR[\fBexpr\fR [\fB:\fR \fBsize\fR ] ] +.fi +.in -2 +.sp + +where \fBexpr\fR evaluates the value of an offset into the packet from a +\fIbase\fR offset which may be \fBether\fR, \fBip\fR, \fBip6\fR, \fBudp\fR, +\fBtcp\fR, or \fBicmp\fR. The \fBsize\fR value specifies the size of the field. +If not given, 1 is assumed. Other legal values are 2 and 4. For example, +.sp +.in +2 +.nf +ether[0] & 1 = 1 +.fi +.in -2 + +is equivalent to \fBmulticast\fR +.sp +.in +2 +.nf +ether[2:4] = 0xffffffff +.fi +.in -2 + +is equivalent to \fBbroadcast\fR. +.sp +.in +2 +.nf +ip[ip[0] & 0xf * 4 : 2] = 2049 +.fi +.in -2 + +is equivalent to \fBudp[0:2] = 2049\fR +.sp +.in +2 +.nf +ip[0] & 0xf > 5 +.fi +.in -2 + +selects \fBIP\fR packets with options. +.sp +.in +2 +.nf +ip[6:2] & 0x1fff = 0 +.fi +.in -2 + +eliminates \fBIP\fR fragments. +.sp +.in +2 +.nf +udp and ip[6:2]&0x1fff = 0 and udp[6:2] != 0 +.fi +.in -2 + +finds all packets with \fBUDP\fR checksums. +.sp +The \fBlength\fR primitive may be used to obtain the length of the packet. For +instance "\fBlength > 60\fR" is equivalent to "\fBgreater 60\fR", and +"\fBether[length \(mi 1]\fR" obtains the value of the last byte in a packet. +.RE + +.sp +.ne 2 +.na +\fB\fBand\fR\fR +.ad +.sp .6 +.RS 4n +Perform a logical \fBAND\fR operation between two boolean values. The \fBAND\fR +operation is implied by the juxtaposition of two boolean expressions, for +example "\fBdinky pinky\fR" is the same as "\fBdinky AND pinky\fR". +.RE + +.sp +.ne 2 +.na +\fB\fBor\fR or \fB,\fR\fR +.ad +.sp .6 +.RS 4n +Perform a logical \fBOR\fR operation between two boolean values. A comma may be +used instead, for example, "\fBdinky,pinky\fR" is the same as "\fBdinky OR +pinky\fR". +.RE + +.sp +.ne 2 +.na +\fB\fBnot\fR or \fB!\fR\fR +.ad +.sp .6 +.RS 4n +Perform a logical \fBNOT\fR operation on the following boolean value. This +operator is evaluated before \fBAND\fR or OR. +.RE + +.sp +.ne 2 +.na +\fB\fBslp\fR\fR +.ad +.sp .6 +.RS 4n +True if the packet is an \fBSLP\fR packet. +.RE + +.sp +.ne 2 +.na +\fB\fBsctp\fR\fR +.ad +.sp .6 +.RS 4n +True if the packet is an \fBSCTP\fR packet. +.RE + +.sp +.ne 2 +.na +\fB\fBospf\fR\fR +.ad +.sp .6 +.RS 4n +True if the packet is an \fBOSPF\fR packet. +.RE + +.RE + +.SH EXAMPLES +.LP +\fBExample 1 \fRUsing the \fBsnoop\fR Command +.sp +.LP +Capture all packets and display them as they are received: + +.sp +.in +2 +.nf +example# \fBsnoop\fR +.fi +.in -2 +.sp + +.sp +.LP +Capture packets with host \fBfunky\fR as either the source or destination and +display them as they are received: + +.sp +.in +2 +.nf +example# \fBsnoop funky\fR +.fi +.in -2 +.sp + +.sp +.LP +Capture packets between \fBfunky\fR and \fBpinky\fR and save them to a file. +Then inspect the packets using times (in seconds) relative to the first +captured packet: + +.sp +.in +2 +.nf +example# \fBsnoop -o cap funky pinky\fR +example# \fBsnoop -i cap -t r | more\fR +.fi +.in -2 +.sp + +.sp +.LP +To look at selected packets in another capture file: + +.sp +.in +2 +.nf +example# \fBsnoop -i pkts -p 99,108\fR + 99 0.0027 boutique -> sunroof NFS C GETATTR FH=8E6 +100 0.0046 sunroof -> boutique NFS R GETATTR OK +101 0.0080 boutique -> sunroof NFS C RENAME FH=8E6C MTra00192 to .nfs08 +102 0.0102 marmot -> viper NFS C LOOKUP FH=561E screen.r.13.i386 +103 0.0072 viper -> marmot NFS R LOOKUP No such file or directory +104 0.0085 bugbomb -> sunroof RLOGIN C PORT=1023 h +105 0.0005 kandinsky -> sparky RSTAT C Get Statistics +106 0.0004 beeblebrox -> sunroof NFS C GETATTR FH=0307 +107 0.0021 sparky -> kandinsky RSTAT R +108 0.0073 office -> jeremiah NFS C READ FH=2584 at 40960 for 8192 +.fi +.in -2 +.sp + +.sp +.LP +To look at packet 101 in more detail: + +.sp +.in +2 +.nf +example# \fBsnoop -i pkts -v -p101\fR +ETHER: ----- Ether Header ----- +ETHER: +ETHER: Packet 101 arrived at 16:09:53.59 +ETHER: Packet size = 210 bytes +ETHER: Destination = 8:0:20:1:3d:94, Sun +ETHER: Source = 8:0:69:1:5f:e, Silicon Graphics +ETHER: Ethertype = 0800 (IP) +ETHER: +IP: ----- IP Header ----- +IP: +IP: Version = 4, header length = 20 bytes +IP: Type of service = 00 +IP: ..0. .... = routine +IP: ...0 .... = normal delay +IP: .... 0... = normal throughput +IP: .... .0.. = normal reliability +IP: Total length = 196 bytes +IP: Identification 19846 +IP: Flags = 0X +IP: .0.. .... = may fragment +IP: ..0. .... = more fragments +IP: Fragment offset = 0 bytes +IP: Time to live = 255 seconds/hops +IP: Protocol = 17 (UDP) +IP: Header checksum = 18DC +IP: Source address = 172.16.40.222, boutique +IP: Destination address = 172.16.40.200, sunroof +IP: +UDP: ----- UDP Header ----- +UDP: +UDP: Source port = 1023 +UDP: Destination port = 2049 (Sun RPC) +UDP: Length = 176 +UDP: Checksum = 0 +UDP: +RPC: ----- SUN RPC Header ----- +RPC: +RPC: Transaction id = 665905 +RPC: Type = 0 (Call) +RPC: RPC version = 2 +RPC: Program = 100003 (NFS), version = 2, procedure = 1 +RPC: Credentials: Flavor = 1 (Unix), len = 32 bytes +RPC: Time = 06-Mar-90 07:26:58 +RPC: Hostname = boutique +RPC: Uid = 0, Gid = 1 +RPC: Groups = 1 +RPC: Verifier : Flavor = 0 (None), len = 0 bytes +RPC: +NFS: ----- SUN NFS ----- +NFS: +NFS: Proc = 11 (Rename) +NFS: File handle = 000016430000000100080000305A1C47 +NFS: 597A0000000800002046314AFC450000 +NFS: File name = MTra00192 +NFS: File handle = 000016430000000100080000305A1C47 +NFS: 597A0000000800002046314AFC450000 +NFS: File name = .nfs08 +NFS: +.fi +.in -2 +.sp + +.sp +.LP +To view just the \fBNFS\fR packets between \fBsunroof\fR and \fBboutique\fR: + +.sp +.in +2 +.nf +example# \fBsnoop -i pkts rpc nfs and sunroof and boutique\fR +1 0.0000 boutique -> sunroof NFS C GETATTR FH=8E6C +2 0.0046 sunroof -> boutique NFS R GETATTR OK +3 0.0080 boutique -> sunroof NFS C RENAME FH=8E6C MTra00192 to .nfs08 +.fi +.in -2 +.sp + +.sp +.LP +To save these packets to a new capture file: + +.sp +.in +2 +.nf +example# \fBsnoop -i pkts -o pkts.nfs rpc nfs sunroof boutique\fR +.fi +.in -2 +.sp + +.sp +.LP +To view encapsulated packets, there will be an indicator of encapsulation: + +.sp +.in +2 +.nf +example# \fBsnoop ip-in-ip\fR +sunroof -> boutique ICMP Echo request (1 encap) +.fi +.in -2 +.sp + +.sp +.LP +If -V is used on an encapsulated packet: + +.sp +.in +2 +.nf +example# \fBsnoop -V ip-in-ip\fR +sunroof -> boutique ETHER Type=0800 (IP), size = 118 bytes +sunroof -> boutique IP D=172.16.40.222 S=172.16.40.200 LEN=104, ID=27497 +sunroof -> boutique IP D=10.1.1.2 S=10.1.1.1 LEN=84, ID=27497 +sunroof -> boutique ICMP Echo request +.fi +.in -2 +.sp + +.LP +\fBExample 2 \fRSetting Up A More Efficient Filter +.sp +.LP +To set up a more efficient filter, the following filters should be used toward +the end of the expression, so that the first part of the expression can be set +up in the kernel: \fBgreater\fR, \fBless\fR, \fBport\fR, \fBrpc\fR, +\fBnofrag\fR, and \fBrelop\fR. The presence of \fBOR\fR makes it difficult to +split the filtering when using these primitives that cannot be set in the +kernel. Instead, use parentheses to enforce the primitives that should be +\fBOR\fR'd. + +.sp +.LP +To capture packets between \fBfunky\fR and \fBpinky\fR of type \fBtcp\fR or +\fBudp\fR on \fBport\fR 80: + +.sp +.in +2 +.nf +example# \fBsnoop funky and pinky and port 80 and tcp or udp\fR +.fi +.in -2 +.sp + +.sp +.LP +Since the primitive \fBport\fR cannot be handled by the kernel filter, and +there is also an \fBOR\fR in the expression, a more efficient way to filter is +to move the \fBOR\fR to the end of the expression and to use parentheses to +enforce the \fBOR\fR between \fBtcp\fR and \fBudp\fR: + +.sp +.in +2 +.nf +example# \fBsnoop funky and pinky and (tcp or udp) and port 80\fR +.fi +.in -2 +.sp + +.SH EXIT STATUS +.sp +.ne 2 +.na +\fB\fB0\fR\fR +.ad +.RS 5n +Successful completion. +.RE + +.sp +.ne 2 +.na +\fB\fB1\fR\fR +.ad +.RS 5n +An error occurred. +.RE + +.SH FILES +.sp +.ne 2 +.na +\fB\fB/dev/audio\fR\fR +.ad +.RS 17n +Symbolic link to the system's primary audio device. +.RE + +.sp +.ne 2 +.na +\fB\fB/dev/null\fR\fR +.ad +.RS 17n +The null file. +.RE + +.sp +.ne 2 +.na +\fB\fB/etc/hosts\fR\fR +.ad +.RS 17n +Host name database. +.RE + +.sp +.ne 2 +.na +\fB\fB/etc/rpc\fR\fR +.ad +.RS 17n +RPC program number data base. +.RE + +.sp +.ne 2 +.na +\fB\fB/etc/services\fR\fR +.ad +.RS 17n +Internet services and aliases. +.RE + +.SH SEE ALSO +.sp +.LP +\fBdladm\fR(1M), \fBifconfig\fR(1M), \fBnetstat\fR(1M), \fBhosts\fR(4), +\fBrpc\fR(4), \fBservices\fR(4), \fBattributes\fR(5), \fBaudio\fR(7I), +\fBipnet\fR(7D), \fBbufmod\fR(7M), \fBdlpi\fR(7P), \fBpfmod\fR(7M) +.sp +.LP +Callaghan, B. and Gilligan, R. \fIRFC 1761, Snoop Version 2 Packet Capture File +Format\fR. Network Working Group. February 1995. +.SH WARNINGS +.sp +.LP +The processing overhead is much higher for real-time packet interpretation. +Consequently, the packet drop count may be higher. For more reliable capture, +output raw packets to a file using the \fB-o\fR option and analyze the packets +offline. +.sp +.LP +Unfiltered packet capture imposes a heavy processing load on the host computer, +particularly if the captured packets are interpreted real-time. This processing +load further increases if verbose options are used. Since heavy use of +\fBsnoop\fR may deny computing resources to other processes, it should not be +used on production servers. Heavy use of \fBsnoop\fR should be restricted to a +dedicated computer. +.sp +.LP +\fBsnoop\fR does not reassemble \fBIP\fR fragments. Interpretation of higher +level protocol halts at the end of the first \fBIP\fR fragment. +.sp +.LP +\fBsnoop\fR may generate extra packets as a side-effect of its use. For example +it may use a network name service (NIS or NIS+) to convert \fBIP\fR addresses +to host names for display. Capturing into a file for later display can be used +to postpone the address-to-name mapping until after the capture session is +complete. Capturing into an NFS-mounted file may also generate extra packets. +.sp +.LP +Setting the \fBsnaplen\fR (\fB-s\fR option) to small values may remove header +information that is needed to interpret higher level protocols. The exact +cutoff value depends on the network and protocols being used. For \fBNFS\fR +Version 2 traffic using \fBUDP\fR on 10 Mb/s Ethernet, do not set \fBsnaplen\fR +less than 150 bytes. For \fBNFS\fR Version 3 traffic using \fBTCP\fR on 100 +Mb/s Ethernet, \fBsnaplen\fR should be 250 bytes or more. +.sp +.LP +\fBsnoop\fR requires information from an \fBRPC\fR request to fully interpret +an \fBRPC\fR reply. If an \fBRPC\fR reply in a capture file or packet range +does not have a request preceding it, then only the \fBRPC\fR reply header will +be displayed. |