NetPacket::IGMP(3)

NAME
NetPacket::IGMP - Assemble and disassemble IGMP (Internet Group Mangement Protocol) packets.

VERSION
version 1.6.0

SYNOPSIS
  use NetPacket::IGMP;

  $igmp_obj = NetPacket::IGMP->decode($raw_pkt);
  $igmp_pkt = NetPacket::IGMP->encode(params...);   # Not implemented
  $igmp_data = NetPacket::IGMP::strip($raw_pkt);

DESCRIPTION
"NetPacket::IGMP" provides a set of routines for assembling and disassembling packets using IGMP (Internet Group Mangement Protocol).

  Methods

"NetPacket::IGMP->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::IGMP->encode(param => value)"
    Return an IGMP packet encoded with the instance data specified. Not implemented.

  Functions

"NetPacket::IGMP::strip([RAW PACKET])"
    Return the encapsulated data (or payload) contained in the IGMP packet. This function returns undef as there is no encapsulated data in an IGMP packet.

  Instance data
The instance data for the "NetPacket::IGMP" object consists of the following fields.

version
    The IGMP version of this packet.

type
    The message type for this packet.

len The length (including length of header) in bytes for this packet.

subtype
    The message subtype for this packet.

cksum
    The checksum for this packet.

group_addr
    The group address specified in this packet.

data
    The encapsulated data (payload) for this packet.

  Exports

default
    none

exportable
    IGMP_VERSION_RFC998 IGMP_VERSION_RFC1112 IGMP_HOST_MQUERY IGMP_HOST_MREPORT IGMP_IP_NO_HOSTS IGMP_IP_ALL_HOSTS IGMP_IP_ALL_ROUTERS

tags
    The following tags group together related exportable items.

    ":strip"
        Import the strip function "igmp_strip".

    ":versions"
        IGMP_VERSION_RFC998 IGMP_VERSION_RFC1112

    ":msgtypes"
        IGMP_HOST_MQUERY IGMP_HOST_MREPORT

    ":group_addrs"
        IGMP_IP_NO_HOSTS IGMP_IP_ALL_HOSTS IGMP_IP_ALL_ROUTERS

    ":ALL"
        All the above exportable items.

EXAMPLE
The following script dumps UDP frames by IP address and UDP port to standard output.

  #!/usr/bin/perl -w

  use strict;
  use Net::PcapUtils;
  use NetPacket::Ethernet qw(:strip);
  use NetPacket::IP;
  use NetPacket::IGMP;

  sub process_pkt {
      my($arg, $hdr, $pkt) = @_;

      my $ip_obj = NetPacket::IP->decode(eth_strip($pkt));
      my $igmp_obj = NetPacket::IGMP->decode($ip_obj->{data});

      print("$ip_obj->{src_ip} -> $ip_obj->{dest_ip} ",
            "$igmp_obj->{type}/$igmp_obj->{subtype} ",
            "$igmp_obj->{group_addr}\n");
  }

  Net::PcapUtils::loop(\&process_pkt, FILTER => 'igmp');

TODO

Implement encode() function

COPYRIGHT
Copyright (c) 2001 Tim Potter.

Copyright (c) 1995,1996,1997,1998,1999 ANU and CSIRO on behalf of the participants in the CRC for Advanced Computational Systems ('ACSys').

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>