TAPPER - sample code for work with tap devices on linux and os x

Copyright (c) 2009-2013, Ivan Vucica, http://ivan.vucica.net/
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-
 Purpose

Providing simple code for creating a tap device, outputting onto stdout the
network traffic generated by kernel for the tap device, and writing into
tap device the traffic from stdin for processing by the kernel.

That is: a two way tunnel between stdio and tap network device.

-
 Requirements

Not sure. You obviously need tun driver for networking (to be able to
create tap device) -- if you don't have /dev/net/tun something's wrong.

Under OS X, you need the tun/tap kernel extension: 
  http://tuntaposx.sf.net/

Otherwise, this was made in the era of 2.6.30 kernels on a 2.6.26 kernel,
and with eglibc 2.9 installed (debian release of eglibc 2.9-12).

It was also tested as of 2013 on Debian and OS X Mountain Lion.

-
 Files

tapper files:
* tapper.c - provides the tap device
* README - this file
* Makefile - builds tapper
* testrun.sh - shows how to use twinpipe and netcat to tunnel traffic
  in a simple way
* pack.sh - packs for use in a certain embedded system

nontapper files:
* TINYFREELICENSE - does not apply to tapper. license of twinpipe.sh
* twinpipe.sh - runs two processes and interconnects them via pipes.

twinpipe was obtained from this URL:
 http://bisqwit.iki.fi/source/twinpipe.html

-
 Alternative tutorial with extra info

This is neat and simple code, but perhaps not best and definitely with 
much room for improvement and cleanup. So here's another nice article:
 http://linuxgazette.net/149/melinte.html 
and another one:
 http://waldner.netsons.org/d2-tuntap.php