NAME

NetPacket::ICMP - Assemble and disassemble ICMP (Internet Control Message Protocol) packets.

VERSION

version 1.6.0

SYNOPSIS

  use NetPacket::ICMP;

  $icmp_obj = NetPacket::ICMP->decode($raw_pkt);
  $icmp_pkt = NetPacket::ICMP->encode();
  $icmp_data = NetPacket::ICMP::strip($raw_pkt);

DESCRIPTION

"NetPacket::ICMP" provides a set of routines for assembling and disassembling packets using ICMP (Internet Control Message Protocol).

Methods

"NetPacket::ICMP->decode([RAW PACKET])": 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.
"NetPacket::ICMP->encode()": Return an ICMP packet encoded with the instance data specified.

Functions

"NetPacket::ICMP::strip([RAW PACKET])": 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.

type: The ICMP message type of this packet.
code: The ICMP message code of this packet.
cksum: The checksum for this packet.
data: The encapsulated data (payload) for this packet.

Exports

default: none
exportable: 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
tags: The following tags group together related exportable items.

":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

":strip"

Import the strip function "icmp_strip".

":ALL"

All the above exportable items.

EXAMPLE

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');

TODO

Create constants

COPYRIGHT

This module is free software. You can redistribute it and/or modify it under the terms of the Artistic License 2.0.

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.

AUTHOR

Tim Potter <tpot@samba.org>

Stephanie Wehner <atrak@itsx.com>