This is new framework of connection tracking, which generalize ip_conntrack
in present kernel to track other layer 3 protocol.
New connection tracking can track not only IPv4 but also IPv6 connections
simultaneously. You can see connections at /proc/net/nf_conntrack.

Note:
	The new IPv4 connection tracking module (nf_conntrack_ipv4) cannot
	work with ip_conntrack. If you want to try nf_conntrack_ipv4,
	please unload ip_conntrack.

	On the other hand, you can use new IPv6 connection tracking module
	(nf_conntrack_ipv6) with ip_conntrack.

TODO:
	- allocate conntrack with various size dependent on features. (done)
	- handling fragmented packets (implemented, but under discussion again)
	- getorigdst() (done)
	- backport recent fixes to ip_conntrack. (done (from linux 2.6.10-rc1)).
	- wrapper for current ip_conntrack and ip_nat
	- matches and targets working with connection tracking
