From: James Chapman <jchapman@katalix.com>
Date: Sat, 26 May 2007 18:47:24 +0100

This driver handles only L2TP data frames; control frames are handled
by a userspace application. It implements L2TP using the PPPoX socket
family. There is a PPPoX socket for each L2TP session in an L2TP tunnel.
PPP data within each session is passed through the kernel's
PPP subsystem via this driver. Kernel parameters of each socket can be
read or modified using ioctl() or [gs]etsockopt() calls.

Signed-off-by: James Chapman <jchapman@katalix.com>

I have no major objections to this patch and would apply
it except for the UDP decapsulation issues.

My suggestion seemingly would work fine here, you could
set the UDP socket callback function pointer when you
set the encap_type.

Please give it a try.

Thanks!