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Date:      Tue, 28 Jul 2009 17:38:12 +0400
From:      Oleg Sharoyko <os@sfedu.ru>
To:        Julian Elischer <julian@elischer.org>
Cc:        freebsd-net@freebsd.org
Subject:   Re: Wrong outgoing interface with multiple routing tables
Message-ID:  <1248788292.71222.10.camel@brain.cc.rsu.ru>
In-Reply-To: <4A6E3743.7050708@elischer.org>
References:  <1248704237.96833.127.camel@brain.cc.rsu.ru> <4A6DE356.6040006@elischer.org> <4A6DEE30.6000108@sfedu.ru> <4A6DFFA1.1010709@elischer.org> <4A6E0121.2020004@sfedu.ru> <4A6E05EC.8050401@elischer.org> <4A6E0A8B.5000103@sfedu.ru> <4A6E2666.2040906@elischer.org>  <4A6E3743.7050708@elischer.org>

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On Mon, 2009-07-27 at 16:24 -0700, Julian Elischer wrote:

> > in addition to the patches already sent you might like to add the 
> > following line to netinet/tcp_input.c
> > 
> >                 }
> >                 inc.inc_fport = th->th_sport;
> >                 inc.inc_lport = th->th_dport;
> >                 inc.inc_fibnum = so->so_fibnum; <-------------
> >                 /*
> >                  * Check for an existing connection attempt in syncache if
> >                  * the flag is only ACK.  A successful lookup creates a new
> >                  * socket appended to the listen queue in SYN_RECEIVED 
> > state.
> >                  */
> 
> in fact you might try just this on its own

With this patch alone all the packets but SYN+ACK are being sent out
correctly. SYN+ACK still uses wrong interface.

ip_output() uses struct inpcb *inp argument to set fib. But when
syncache_respond() sends SYN+ACK, ip_output() is being called without
inp (from netinet/tcp_syncache.c, syncache_respond()):

 error = ip_output(m, sc->sc_ipopts, NULL, 0, NULL, NULL);

It I add
 M_SETFIB(m, sc->sc_inc.inc_fibnum);

before the call to ip_output(), then SYN+ACK goes the right way.

-- 
Oleg Sharoyko.
Software and Network Engineer
Computer Center of Rostov State University.




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