NAME

NetPacket::UDP - Assemble and disassemble UDP (User Datagram Protocol) packets.

SYNOPSIS

use NetPacket::UDP;

$udp_obj = NetPacket::UDP->decode($raw_pkt);
$udp_pkt = NetPacket::UDP->encode(params...);   # Not implemented
$udp_data = NetPacket::UDP::strip($raw_pkt);

DESCRIPTION

NetPacket::UDP provides a set of routines for assembling and disassembling packets using UDP (User Datagram Protocol).

Methods

NetPacket::UDP->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::UDP->encode(param => value)

Return a UDP packet encoded with the instance data specified. Not implemented.

Functions

NetPacket::UDP::strip([RAW PACKET])

Return the encapsulated data (or payload) contained in the UDP packet. This data is suitable to be used as input for other NetPacket::* modules.

This function is equivalent to creating an object using the decode() constructor and returning the data field of that object.

Instance data

The instance data for the NetPacket::UDP object consists of the following fields.

src_port

The source UDP port for the datagram.

dest_port

The destination UDP port for the datagram.

len

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

cksum

The checksum value for this packet.

data

The encapsulated data (payload) for this packet.

Exports

default

none

exportable

igmp_strip IGMP_VERSION_RFC998 IGMP_VERSION_RFC1112 IGMP_MSG_HOST_MQUERY IGMP_MSG_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 IGMP the contents of IGMP frames to standard output.

  #!/usr/bin/perl

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

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

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

      print("$ip_obj->{src_ip}:$udp_obj->{src_port} -> ",
	    "$ip_obj->{dest_ip}:$udp_obj->{dest_port} ",
	    "$udp_obj->{len}\n");
  }

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

TODO

Implement encode() function

COPYRIGHT

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@acsys.anu.edu.au>