multihome patch

[a]

Hi, all.

I made another multihome pacth for ipfilter.
This makes it possible to load-balance up-stream
access-lines dynamically by making use of RTT.

On a patched ipfilter router, TCP SYN packets
are duplicated and forwarded to a TCP server
through every access-line. The source address
is re-written to the out-going network interface's
address.
When TCP SYN-ACKs returns, the ealiest one in
the TCP session is accepted as a normal SYN-ACK
and other late comers are dropped and instead
RST packets are sent to them.

Please refer to the page below for patches and
for further description.
http://www.arifumi.net/mhmap.html

Though I just made a patch for NetBSD, I guess
this doesn't have much dependency on it.
I'd like to have any comments.

Thanks.