Libnet provides a fairly portable framework for network packet construction an injection.
It is widely used, but had become unmaintained at packetfactory.net, and its author is unreachable.
This version was forked from the 1.1.3 release candidate, then bug fixed, actively maintained, and rereleased.
Contact Sam Roberts vieuxtech@gmail.com if you have patches, find bugs, or have issues porting or building against it.
Newest code is at:
http://github.com/sam-github/libnet
Releases are at:
http://sourceforge.net/projects/libnet-dev/
Some old docs are at:
http://packetfactory.openwall.net/projects/libnet/index.html
A C library for portable packet creation and injection
Libnet is an API to help with the construction and handling of network packets. It provides a portable framework for low-level network packet writing and handling (use libnet in conjunction with libpcap and you can write some really cool stuff). Libnet includes packet creation at the IP layer and at the link layer as well as a host of supplementary and complementary functionality. Libnet is very handy with which to write network tools and network test code. See the manpage and sample test code for more detailed information.
Your old code (circa libnet-1.0.x) WILL NOT WORK with libnet-1.1.x. Read doc/MIGRATION for easy steps on porting your old code.
LIBNET 1.1 (c) 1998 - 2004 Mike D. Schiffman mike@infonexus.com http://www.packetfactory.net/libnet
LIBNET 1.1.3 and later (c) 2009 - 2013 Sam Roberts vieuxtech@gmail.com http://github.com/sam-github/libnet