---
name: "NetPacket::IGMP"
section: "3pm"
platform: "linux"
package: "libnetpacket-perl"
version: "1.7.2-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/NetPacket::IGMP"
---

# NetPacket::IGMP(3pm)

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

## 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\>