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.

AUTHOR

Patrice <GomoR> Auffret

COPYRIGHT AND LICENSE

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