Wrong outgoing interface with multiple routing tables

[Julian Elischer]

Julian Elischer wrote:
> So there are two possible ways a daemon might assign a fib to a socket 
> that it is accepting:
> 
> 1/  the accept socket could take the FIB of the process.
> 2/  the accept socket could take the fib of the incoming SYN packet.
> 
> I chose #1, but it is possible something in changes between 6
> and 7 broke the "chain of custody" for the fib.
> This code is in production in 6.x based systems but was only introduced 
> to FreeBSD in 7.x.
> 
> The process makes a socket which inherits the fib from it.
> The socket includes an INET PCB (Protocol Control Block)
> which gets a copy too..
> when "listen() is called and a syn comes in, a new entry is made in the 
> syncache code and this includes a new connection block which is supposed 
> to inherrit the fib number from the originating listen socket.
> 
> Eventually a new socket is created and it is supposed to inherit teh
> fibnum from the syncache entry, and to copy it to the inpcb attached to it.
> 
> It's possible that somewhere this has been broken by changes.
> but I don't see it right at the moment.
found one place in kern/ipc_socket.c

in sonewconn()
------
         so->so_linger = head->so_linger;
         so->so_state = head->so_state | SS_NOFDREF;
         so->so_proto = head->so_proto;
         so->so_fibnum = head->so_fibnum;  <------  Add this
         so->so_cred = crhold(head->so_cred);
#ifdef MAC
         SOCK_LOCK(head);
         mac_create_socket_from_socket(head, so);
         SOCK_UNLOCK(head);
#endif
--------
and in netinet/tcp_syncache.c
in syncache_socket()

change the following:
------
         inp = sotoinpcb(so);
         inp->inp_inc.inc_fibnum = so->so_fibnum;
         INP_WLOCK(inp);

         /* Insert new socket into PCB hash list. */
------

and see if this helps
(it may not, there may be another code path I'm missing).

> 
> 
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