NAME

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

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.

  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.

AUTHOR

Tim Potter <tpot@samba.org>