NAME¶

Net::Frame::Layer::TCP - Transmission Control Protocol layer object

SYNOPSIS¶

   use Net::Frame::Layer::TCP qw(:consts);
   # Build a layer
   my $layer = Net::Frame::Layer::TCP->new(
      src      => getRandomHighPort(),
      dst      => 0,
      seq      => getRandom32bitsInt(),
      ack      => 0,
      x2       => 0,
      off      => 0,
      flags    => NF_TCP_FLAGS_SYN,
      win      => 0xffff,
      checksum => 0,
      urp      => 0,
      options  => '',
   );
   $layer->pack;
   print 'RAW: '.$layer->dump."\n";
   # Read a raw layer
   my $layer = Net::Frame::Layer::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::Frame::Layer 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.

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 TCP options.

getOptionsLength

Returns options length in bytes.

computeLengths

Computes various lengths contained within this layer.

computeChecksums ({ type => PROTO, src => IP, dst => IP })

In order to compute checksums of TCP, you need to pass the protocol type (IPv4, IPv6), the source and destination IP addresses (IPv4 for IPv4, IPv6 for IPv6).

getKey

getKeyReverse

These two methods are basically used to increase the speed when using recv method from Net::Frame::Simple. Usually, you write them when you need to write match method.

match (Net::Frame::Layer::TCP object)

This method is mostly used internally. You pass a Net::Frame::Layer::TCP layer as a parameter, and it returns true if this is a response corresponding for the request, or returns false if not.

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::TCP qw(:consts);

NF_TCP_FLAGS_FIN

NF_TCP_FLAGS_SYN

NF_TCP_FLAGS_RST

NF_TCP_FLAGS_PSH

NF_TCP_FLAGS_ACK

NF_TCP_FLAGS_URG

NF_TCP_FLAGS_ECE

NF_TCP_FLAGS_CWR

TCP flags constants.

SEE ALSO¶

Net::Frame::Layer

AUTHOR¶

Patrice <GomoR> Auffret

COPYRIGHT AND LICENSE¶

Copyright (c) 2006-2019, Patrice <GomoR> Auffret

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