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NetPacket version 0.41.1
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This is a whole bunch of
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Perl modules which I have named NetPacket::*. These modules do basic
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disassembly of network packets of various Internet protocols. NetPacket
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0.01 contained hooks for assembly of packets which have been implemented in
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version 0.04 by Stephanie Wehner <atrak@itsx.com>.
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I've used these scripts for a variety of little jobs such as snooping
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various TCP services, gathering network traffic statistics by
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source/destination/protocol, and for unpacking the contents of IP
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tunnels. They're actually pretty useful. I recommend fetching and
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installing the Net::Pcap module to actually gather packet data, and
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for writing small scripts based on packet capture, the Net::PcapUtils
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module is also useful.
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At present, decoding for the following protocols has been
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- Ethernet (802.3 and 802.2)
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It's pretty easy to add new protocols. Just copy one of the existing
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modules and figure out an unpack string which will unpack the
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information in the packet and store the data into fields in the
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namespace of the NetPacket::whatever object. More information can be
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found in the NetPacket(3) manpage, which is the base class module.
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I'd be interested in receiving bug reports, comments or any
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improvements (especially additional protocols) to the NetPacket
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NetPacket - assemble/disassemble network packets at the protocol level
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# NetPacket is a base class only
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"NetPacket" provides a base class for a cluster of modules related to
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decoding and encoding of network protocols. Each "NetPacket" descendent
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module knows how to encode and decode packets for the network protocol
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it implements. Consult the documentation for the module in question for
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protocol-specific implementation.
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Note that there is no inheritance in the "NetPacket::" cluster of
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modules other than each protocol module being a "NetPacket". This was
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seen to be too restrictive as imposing inheritance relationships (for
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example between the IP, UDP and TCP protocols) would make things like
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tunneling or other unusual situations difficult.
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WRITING YOUR OWN "NetPacket::" MODULE
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You are encouraged to write additional "NetPacket::" modules as well as
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improve existing ones. Contact the maintainer of the module in question
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with your suggestions or changes.
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The following sections are a list of suggestions and conventions for
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writing a "NetPacket::" module.
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When creating a module in the "NetPacket::" namespace, it is suggested
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that you stick to a couple of conventions when naming packet contents.
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This will hopefully lead to a consistent namespace making the
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"NetPacket::" easier to use.
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Content names are all lowercase, with underscores separating multiple
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words. The following abbreviations are recommended:
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--------------------------------
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encode(), decode(), strip()
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Every NetPacket:: object should have the following fields.
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A link to the parent "NetPacket::" object in which this
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"NetPacket::" object is encaulated. This field is undefined if there
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A copy of the raw data of the packet.
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This field should contain the data encapsulated in the packet (i.e
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any headers or trailers stripped off) or undef if the packet
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contains no data. Note that in this sense, "data" is taken to mean
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information not relevant to the particular protocol being decoded.
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For example, an ARP packet contains many header fields but no data.
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A UDP datagram, however contains header fields and a payload.
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Joel Knight has a patch for NetPacket for IPv6 support available at
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http://www.packetmischief.ca/code/netpacket/.
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Copyright (c) 2001 Tim Potter and Stephanie Wehner.
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Copyright (c) 1995,1996,1997,1998,1999 ANU and CSIRO on behalf of the
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participants in the CRC for Advanced Computational Systems ('ACSys').
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This module is free software. You can redistribute it and/or modify it
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under the terms of the Artistic License 2.0.
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This program is distributed in the hope that it will be useful, but
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without any warranty; without even the implied warranty of
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merchantability or fitness for a particular purpose.
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Tim Potter <tpot@samba.org>
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Stephanie Wehner <atrak@itsx.com>
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Yanick Champoux <yanick@cpan.org>
added
removed
README
