NAME

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

VERSION

       version 1.7.2

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 Management 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>