NAME

Net::Packet::TCP - Transmission Control Protocol layer 4 object

SYNOPSIS

   use Net::Packet::Consts qw(:tcp);
   require Net::Packet::TCP;

   # Build a layer
   my $layer = Net::Packet::TCP->new(
      dst     => 22,
      options => "\x02\x04\x05\xb4", # MSS=1460
   );
   $layer->pack;

   print 'RAW: '.unpack('H*', $layer->raw)."\n";

   # Read a raw layer
   my $layer = Net::Packet::TCP->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 TCP layer.

RFC: ftp://ftp.rfc-editor.org/in-notes/rfc793.txt

See also Net::Packet::Layer and Net::Packet::Layer4 for other attributes and methods.

ATTRIBUTES

src

dst

Source and destination ports.

flags

TCP flags, see CONSTANTS.

win

The window size.

seq

ack

Sequence and acknowledgment numbers.

off

The size in number of words of the TCP header.

x2

Reserved field.

checksum

The TCP header checksum.

urp

Urgent pointer.

options

TCP options, as a hexadecimal string.

METHODS

new

Object constructor. You can pass attributes that will overwrite default ones. Default values:

src: getRandomHighPort()

dst: 0

seq: getRandom32bitsInt()

ack: 0

x2: 0

off: 0

flags: NP_TCP_FLAG_SYN

win: 0xffff

checksum: 0

urp: 0

options: ""

recv

Will search for a matching replies in framesSorted or frames from a Net::Packet::Dump object.

pack

Packs all attributes into a raw format, in order to inject to network. Returns 1 on success, undef otherwise.

unpack

Unpacks raw data from network and stores attributes into the object. Returns 1 on success, undef otherwise.

getHeaderLength

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

getOptionsLength

Returns options length in bytes.

haveFlagFin

haveFlagSyn

haveFlagRst

haveFlagPsh

haveFlagAck

haveFlagUrg

haveFlagEce

haveFlagCwr

Returns 1 if the specified TCP flag is set in flags attribute, 0 otherwise.

CONSTANTS

Load them: use Net::Packet::Consts qw(:tcp);

NP_TCP_FLAG_FIN

NP_TCP_FLAG_SYN

NP_TCP_FLAG_RST

NP_TCP_FLAG_PSH

NP_TCP_FLAG_ACK

NP_TCP_FLAG_URG

NP_TCP_FLAG_ECE

NP_TCP_FLAG_CWR

TCP flag constants.

AUTHOR

Patrice <GomoR> Auffret

COPYRIGHT AND LICENSE

Copyright (c) 2004-2006, Patrice <GomoR> Auffret

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

RELATED MODULES

NetPacket, Net::RawIP, Net::RawSock