This is a fork of the official xl2tpd source (v1.3.17) with modified source and setups to generate xl2tpd6: an IPv6 L2TP server, allowing IPv4 inside IPv6 tunneling. This version have kernel support for L2TP Tunneling.
For now, server builds and seems fully functional, but listen-addr is NOT taken into account in the configuration, it will listen on :: (any IPV6 address)
Scripts for package generation are not yet functional, simply compile it, it will generate an xl2tpd6 binary, that you can copy manually to same binary path as your legacy xl2tpd.
For the configuration, it will by default try to read /etc/xl2tpd/xl2tpd6.conf
For the Startup, you will have inside debian/xl2tpd6.init a rc.init file that works
Of course, this binary can run aside of the legacy xl2tpd binary (one listening in IPv4, the other in IPv6).