"NetPacket::ICMP" - Assemble and disassemble ICMP (Internet Control Message Protocol) packets. use NetPacket::ICMP; $icmp_obj = NetPacket::ICMP->decode($raw_pkt); $icmp_pkt = NetPacket::ICMP->encode(); $icmp_data = NetPacket::ICMP::strip($raw_pkt); "NetPacket::ICMP" provides a set of routines for assembling and disassembling packets using ICMP (Internet Control Message Protocol).

Methods
Decode the raw packet data given and return an object containing instance data. This method will quite happily decode garbage input. It is the responsibility of the programmer to ensure valid packet data is passed to this method. Return an ICMP packet encoded with the instance data specified.

Functions
Return the encapsulated data (or payload) contained in the ICMP packet.

Instance data
The instance data for the "NetPacket::ICMP" object consists of the following fields. The ICMP message type of this packet. The ICMP message code of this packet. The checksum for this packet. The encapsulated data (payload) for this packet.

Exports
none ICMP message types: ICMP_ECHOREPLY ICMP_UNREACH ICMP_SOURCEQUENCH ICMP_REDIRECT ICMP_ECHO ICMP_ROUTERADVERT ICMP_ROUTERSOLICIT ICMP_TIMXCEED ICMP_PARAMPROB ICMP_TSTAMP ICMP_TSTAMPREPLY ICMP_IREQ ICMP_IREQREPLY ICMP_MASKREQ ICMP_MASKREPLY The following tags group together related exportable items. ICMP_ECHOREPLY ICMP_UNREACH ICMP_SOURCEQUENCH ICMP_REDIRECT ICMP_ECHO ICMP_ROUTERADVERT ICMP_ROUTERSOLICIT ICMP_TIMXCEED ICMP_PARAMPROB ICMP_TSTAMP ICMP_TSTAMPREPLY ICMP_IREQ ICMP_IREQREPLY ICMP_MASKREQ ICMP_MASKREPLY Import the strip function "icmp_strip". All the above exportable items. The following example prints the ICMP type, code, and checksum fields. #!/usr/bin/perl -w use strict; use Net::PcapUtils; use NetPacket::Ethernet qw(:strip); use NetPacket::IP qw(:strip); use NetPacket::ICMP; sub process_pkt { my ($user, $hdr, $pkt) = @_; my $ip_obj = NetPacket::IP->decode(eth_strip($pkt)); my $icmp_obj = NetPacket::ICMP->decode(ip_strip($ip_obj)); print("Type: $icmp_obj->{type}\n"); print("Code: $icmp_obj->{code}\n"); print("Checksum: $icmp_obj->{cksum}\n\n"); } Net::PcapUtils::loop(\&process_pkt, FILTER => 'icmp'); Copyright (c) 2001 Tim Potter. This package is free software and is provided "as is" without express or implied warranty. It may be used, redistributed and/or modified under the terms of the Perl Artistic License (see http://www.perl.com/perl/misc/Artistic.html) Copyright (c) 1995,1996,1997,1998,1999 ANU and CSIRO on behalf of the participants in the CRC for Advanced Computational Systems ('ACSys'). ACSys makes this software and all associated data and documentation ('Software') available free of charge. You may make copies of the Software but you must include all of this notice on any copy. The Software was developed for research purposes and ACSys does not warrant that it is error free or fit for any purpose. ACSys disclaims any liability for all claims, expenses, losses, damages and costs any user may incur as a result of using, copying or modifying the Software. Tim Potter <tpot@samba.org> Stephanie Wehner <atrak@itsx.com>