NAME

       NetPacket::IP - Assemble and disassemble IP (Internet Protocol) packets.

VERSION

       version 1.7.2

SYNOPSIS

         use NetPacket::IP;

         $ip_obj = NetPacket::IP->decode($raw_pkt);
         $ip_pkt = NetPacket::IP->encode($ip_obj);
         $ip_data = NetPacket::IP::strip($raw_pkt);

DESCRIPTION

       "NetPacket::IP" provides a set of routines for assembling and disassembling packets using
       IP (Internet Protocol).

   Methods
       "NetPacket::IP->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::IP->encode()"
           Return an IP packet encoded with the instance data specified. This will infer the
           total length of the packet automatically from the payload length and also adjust the
           checksum.

   Functions
       "NetPacket::IP::strip([RAW PACKET])"
           Return the encapsulated data (or payload) contained in the IP 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::IP" object consists of the following fields.

       ver The IP version number of this packet.

       hlen
           The IP header length of this packet.

       flags
           The IP header flags for this packet.

       foffset
           The IP fragment offset for this packet.

       tos The type-of-service for this IP packet.

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

       id  The identification (sequence) number for this IP packet.

       ttl The time-to-live value for this packet.

       proto
           The IP protocol number for this packet.

       cksum
           The IP checksum value for this packet.

       src_ip
           The source IP address for this packet in dotted-quad notation.

       dest_ip
           The destination IP address for this packet in dotted-quad notation.

       options
           Any IP options for this packet.

       data
           The encapsulated data (payload) for this IP packet.

   Exports
       default
           none

       exportable
           IP_PROTO_IP IP_PROTO_ICMP IP_PROTO_IGMP IP_PROTO_IPIP IP_PROTO_TCP IP_PROTO_UDP
           IP_VERSION_IPv4

       tags
           The following tags group together related exportable items.

           ":protos"
               IP_PROTO_IP IP_PROTO_ICMP IP_PROTO_IGMP IP_PROTO_IPIP IP_PROTO_TCP IP_PROTO_UDP

           ":versions"
               IP_VERSION_IPv4

           ":strip"
               Import the strip function "ip_strip".

           ":ALL"
               All the above exportable items.

EXAMPLE

       The following script dumps IP frames by IP address and protocol to standard output.

         #!/usr/bin/perl -w

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

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

             my $ip_obj = NetPacket::IP->decode(eth_strip($pkt));
             print("$ip_obj->{src_ip}:$ip_obj->{dest_ip} $ip_obj->{proto}\n");
         }

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

TODO

       IP option decoding - currently stored in binary form.
       Assembly of received fragments

COPYRIGHT

       Copyright (c) 2001 Tim Potter and Stephanie Wehner.

       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>

       Stephanie Wehner <atrak@itsx.com>