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Date:      Sat, 12 Feb 2011 14:47:54 +0530
From:      Naveen Gujje <gujjenaveen@gmail.com>
To:        freebsd-hackers@freebsd.org
Subject:   SO_SETFIB socket option
Message-ID:  <AANLkTimDu20-Q6n0sCgafGQb1G6Pj8bOVDtvcU%2B4UUKM@mail.gmail.com>
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Hi All,

On my FreeBSD 7.2 box, I've two routing tables (FIBs). Fib 0 and Fib 1
(net.fibs = 2).

I have a simple echo client which is the counterpart of an echo server
running somewhere.
If I run this echo client against fib 0 as 'setfib 0 ./echo-client', it
properly uses Fib 0.
But, if I run this echo client against Fib 0 by using setsockopt & SO_SETFIB
option, setsockopt fails with EINVAL.

setsockopt & SO_SETFIB for Fib 1 succeeds. But it fails for Fib 0.

By looking at the man page and /sys/kern/uipc_socket.c

Excerpt from setsockopt(2) man page:

"SO_SETFIB can be used to over-ride the default FIB (routing table) for
  the given socket.  The value must be from 0 to one less than the number
  returned from the sysctl net.fibs."

and this contrasts with the code in /sys/kern/uipc_socket.c

 <http://fxr.watson.org/fxr/source/kern/uipc_socket.c?v=FREEBSD72#L2210>;
                case SO_SETFIB
<http://fxr.watson.org/fxr/ident?v=FREEBSD72;im=bigexcerpts;i=SO_SETFIB>:
 <http://fxr.watson.org/fxr/source/kern/uipc_socket.c?v=FREEBSD72#L2211>;
                        error
<http://fxr.watson.org/fxr/ident?v=FREEBSD72;im=bigexcerpts;i=error>; =
sooptcopyin <http://fxr.watson.org/fxr/ident?v=FREEBSD72;im=bigexcerpts;i=sooptcopyin>(sopt,
&optval, sizeof optval,
 <http://fxr.watson.org/fxr/source/kern/uipc_socket.c?v=FREEBSD72#L2212>;
                                            sizeof optval);
 <http://fxr.watson.org/fxr/source/kern/uipc_socket.c?v=FREEBSD72#L2213>;
                        if (optval < 1 || optval > rt_numfibs
<http://fxr.watson.org/fxr/ident?v=FREEBSD72;im=bigexcerpts;i=rt_numfibs>)
{
 <http://fxr.watson.org/fxr/source/kern/uipc_socket.c?v=FREEBSD72#L2214>;
                                error
<http://fxr.watson.org/fxr/ident?v=FREEBSD72;im=bigexcerpts;i=error>; =
EINVAL <http://fxr.watson.org/fxr/ident?v=FREEBSD72;im=bigexcerpts;i=EINVAL>;
 <http://fxr.watson.org/fxr/source/kern/uipc_socket.c?v=FREEBSD72#L2215>;
                                goto bad;
                         }

Where as both Fib 0 and Fib 1 work fine if I use setfib() call.

So, am confused if the code is incorrect or man page.

I want to run the echo-client process against Fib 1, but selectively change
it to Fib 0 for few connections.
So, is this possible with the current freebsd multiple routing table (MRT)?

Thanks,
Naveen G.

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