NAME¶
NetPacket - assemble/disassemble network packets at the protocol level
VERSION¶
version 1.3.0
SYNOPSIS¶
# NetPacket is a base class only
DESCRIPTION¶
"NetPacket" provides a base class for a cluster of modules related to
decoding and encoding of network protocols. Each "NetPacket"
descendent module knows how to encode and decode packets for the network
protocol it implements. Consult the documentation for the module in question
for protocol-specific implementation.
Note that there is no inheritance in the "NetPacket::" cluster of
modules other than each protocol module being a "NetPacket". This
was seen to be too restrictive as imposing inheritance relationships (for
example between the IP, UDP and TCP protocols) would make things like
tunneling or other unusual situations difficult.
WRITING YOUR OWN "NetPacket::" MODULE¶
You are encouraged to write additional "NetPacket::" modules as well
as improve existing ones. Contact the maintainer of the module in question
with your suggestions or changes.
The following sections are a list of suggestions and conventions for writing a
"NetPacket::" module.
Naming Conventions¶
When creating a module in the "NetPacket::" namespace, it is suggested
that you stick to a couple of conventions when naming packet contents. This
will hopefully lead to a consistent namespace making the
"NetPacket::" easier to use.
Content names are all lowercase, with underscores separating multiple words. The
following abbreviations are recommended:
Word Abbreviation
--------------------------------
source src
destination dest
checksum cksum
identifier id
version ver
protocol proto
Required Methods¶
encode(),
decode(),
strip()
Required Fields¶
Every NetPacket:: object should have the following fields.
- _parent
- A link to the parent "NetPacket::" object in
which this "NetPacket::" object is encaulated. This field is
undefined if there is no parent object.
- _frame
- A copy of the raw data of the packet.
- data
- This field should contain the data encapsulated in the
packet (i.e any headers or trailers stripped off) or undef if the packet
contains no data. Note that in this sense, "data" is taken to
mean information not relevant to the particular protocol being decoded.
For example, an ARP packet contains many header fields but no data. A UDP
datagram, however contains header fields and a payload.
SEE ALSO¶
Joel Knight has a patch for NetPacket for IPv6 support available at
http://www.packetmischief.ca/code/netpacket/.
COPYRIGHT AND LICENSE¶
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.
AUTHORS¶
Tim Potter <tpot@samba.org>
Stephanie Wehner <atrak@itsx.com>
Yanick Champoux <yanick@cpan.org>