Patrice Auffret > Net-Frame > Net::Frame::Layer::IPv4

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NAME ^

Net::Frame::Layer::IPv4 - Internet Protocol v4 layer object

SYNOPSIS ^

   use Net::Frame::Layer::IPv4 qw(:consts);

   # Build a layer
   my $layer = Net::Frame::Layer::IPv4->new(
      version  => 4,
      tos      => 0,
      id       => getRandom16bitsInt(),
      length   => NF_IPv4_HDR_LEN,
      hlen     => 5,
      flags    => 0,
      offset   => 0,
      ttl      => 128,
      protocol => NF_IPv4_PROTOCOL_TCP,
      checksum => 0,
      src      => '127.0.0.1',
      dst      => '127.0.0.1',
      options  => '',
      noFixLen => 0,
   );
   $layer->pack;

   print 'RAW: '.$layer->dump."\n";

   # Read a raw layer
   my $layer = Net::Frame::Layer::IPv4->new(raw => $raw);

   print $layer->print."\n";
   print 'PAYLOAD: '.unpack('H*', $layer->payload)."\n"
      if $layer->payload;

DESCRIPTION ^

This modules implements the encoding and decoding of the IPv4 layer.

RFC: ftp://ftp.rfc-editor.org/in-notes/rfc791.txt

See also Net::Frame::Layer for other attributes and methods.

ATTRIBUTES ^

id

IP ID of the datagram.

ttl

Time to live.

src
dst

Source and destination IP addresses.

protocol

Of which type the layer 4 is.

checksum

IP checksum.

flags

IP Flags.

offset

IP fragment offset.

version

IP version, here it is 4.

tos

Type of service flag.

length

Total length in bytes of the packet, including IP headers (that is, layer 3 + layer 4 + layer 7).

hlen

Header length in number of words, including IP options.

options

IP options, as a hexadecimal string.

noFixLen

Since the byte ordering of length attribute varies from system to system, a subroutine inside this module detects which byte order to use. Sometimes, like when you build Net::Frame::Layer::8021Q layers, you may have the need to avoid this. So set it to 1 in order to avoid fixing. Default is 0 (that is to fix).

The following are inherited attributes. See Net::Frame::Layer for more information.

raw
payload
nextLayer

METHODS ^

new
new (hash)

Object constructor. You can pass attributes that will overwrite default ones. See SYNOPSIS for default values.

getHeaderLength

Returns the header length in bytes, not including IP options.

getOptionsLength

Returns the length in bytes of IP options. 0 if none.

computeLengths ({ payloadLength => VALUE })

In order to compute lengths attributes within IPv4 header, you need to pass via a hashref the number of bytes contained in IPv4 payload (that is, the sum of all layers after the IPv4 one).

computeChecksums

Computes the IPv4 checksum.

The following are inherited methods. Some of them may be overridden in this layer, and some others may not be meaningful in this layer. See Net::Frame::Layer for more information.

layer
computeLengths
computeChecksums
pack
unpack
encapsulate
getLength
getPayloadLength
print
dump

CONSTANTS ^

Load them: use Net::Frame::Layer::IPv4 qw(:consts);

NF_IPv4_PROTOCOL_ICMPv4
NF_IPv4_PROTOCOL_IGMP
NF_IPv4_PROTOCOL_IPIP
NF_IPv4_PROTOCOL_TCP
NF_IPv4_PROTOCOL_EGP
NF_IPv4_PROTOCOL_IGRP
NF_IPv4_PROTOCOL_CHAOS
NF_IPv4_PROTOCOL_UDP
NF_IPv4_PROTOCOL_IDP
NF_IPv4_PROTOCOL_DCCP
NF_IPv4_PROTOCOL_IPv6
NF_IPv4_PROTOCOL_IPv6ROUTING
NF_IPv4_PROTOCOL_IPv6FRAGMENT
NF_IPv4_PROTOCOL_IDRP
NF_IPv4_PROTOCOL_RSVP
NF_IPv4_PROTOCOL_GRE
NF_IPv4_PROTOCOL_ESP
NF_IPv4_PROTOCOL_AH
NF_IPv4_PROTOCOL_ICMPv6
NF_IPv4_PROTOCOL_EIGRP
NF_IPv4_PROTOCOL_OSPF
NF_IPv4_PROTOCOL_ETHERIP
NF_IPv4_PROTOCOL_PIM
NF_IPv4_PROTOCOL_VRRP
NF_IPv4_PROTOCOL_STP
NF_IPv4_PROTOCOL_SCTP
NF_IPv4_PROTOCOL_UDPLITE

Various protocol type constants.

NF_IPv4_MORE_FRAGMENT
NF_IPv4_DONT_FRAGMENT
NF_IPv4_RESERVED_FRAGMENT

Various possible flags.

SEE ALSO ^

Net::Frame::Layer

AUTHOR ^

Patrice <GomoR> Auffret

COPYRIGHT AND LICENSE ^

Copyright (c) 2006-2014, Patrice <GomoR> Auffret

You may distribute this module under the terms of the Artistic license. See LICENSE.Artistic file in the source distribution archive.

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