Consider using the version at https://github.com/ntop/n2n as a lot of improvements from here have been ported to over there.
This is a development branch of the n2n p2p vpn software.
It contains some modifications of the v2 version of n2n, which is the latest stable version and should be used for productive environments. All the current development happens in this repository in the new_protocol branch, which is intended to be come version v3 of n2n and then merged back into the original svn repository on ntop.org.
Uses sglib http://sglib.sourceforge.net.
For further information please visit the wiki https://github.com/meyerd/n2n/wiki.