NetPacket::IGMP(3p)

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>