This is a library from Steinwurf ApS free for educational and research purposes. I was part of starting Steinwurf back in 2011 and wrote the initial versions of Kodo.

Kodo is a flexible C++ network coding, intended to be used for commercial applications and for research on implementation of Network Coding. The library enable researchers to implement, new codes and algorithms, perform simulations, and benchmark the coding operations on any platform where a C++ compiler is available. The library provide a multitude of build blocks and parameters that can be combined in order to create codes. To ensure ease of use several codes are predefined, and high level API’s provided.

The library is available via GitHub, to gain access you need to sign up for a research/commercial license here: http://steinwurf.com/license

From the author’s description:

This project is composed by three libraries:

ncutils-java and ncutils-c: these two libraries provide slow but flexible functions to implement network coding ideas both in pure Java and C.
ncutils-codec: this library provides an implementation of random network coding over F2^8. This library is faster than the above but is less flexible. It includes native code to accelerate both encoding and decoding.

Source: https://code.google.com/p/ncutils/

Implementation of the Network Coded TCP (CTCP) by Gregoire Delannoy as part of his final year project at Dublin City University.

Author’s description:

TCPeP is a Performance-Enhancing proxy for TCP over lossy links, using Network Coding principles. It is partly based on the paper “Network coded tcp – CTCP”.
Standard TCP algorithm were designed with wired networks in mind, assuming that all losses resulted from congestion events.
Coded-TCP is based on the assumption that losses can be completely random, as it occurs in some wireless links.

Source: https://github.com/GregoireDelannoy/TCPeP