From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jeremy Kerr <jeremy@redfishsoftware.com.au>
Subject: Re: How to take over TCP connection from userspace process?
Date: Wed, 22 Oct 2003 14:15:23 +1000
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> What I need is: after I authenticated TCP connection A(host A connected to
> me) and TCP connection B(host B connected to me), then let what host A send
> (through TCP connection A)directly forward to host B(through TCP connection
> B) in the kernel ,meanwhile, what host B send directly forward to host A in
> the kernel.

Sounds like the LVS project's TCP splicing code is what you're after:

http://www.linuxvirtualserver.org/software/tcpsp/index.html

This allows you to connect ('splice') two sockets together in userspace, so 
the subsequent forwarding is handled within the kernel. I've never used it 
myself though.


Jeremy