TCP options order changed in FreeBSD 7, incompatible with some routers

[d.s. al coda]

On 3/12/08, Andre Oppermann <andre at freebsd.org> wrote:

>
> I'd be very interesting to know the exactly models and their firmware
> version
> of the affected routers.  If available locally I'd like to obtain a
> similar
> model myself for future regression tests.


Here are the models we managed to hear about via email:
D-Link WBR-1310
Linksys WCG200 (with firewall enabled)
Encore Broadband Router
Linksys WAG354G
Ambit U10C019
Netgear CG814GCMR

We didn't get any firmware version info that I know of. Hope this is still
helpful.


>
> We've already fixed two issues.  The first changes the order of the TCP
> options
> and is in this change:
>
>
> http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/netinet/tcp_var.h.diff?r1=1.160;r2=1.161
>
> It is to solve a problem observed by ISC that sounds very much like what
> you
> describe.  This fixed the issue in this case.
>
> The second changes the alignment padding from NOP to 0x00.  Whether this
> was
> a contributing factor to the reported problem is not clear.  There hasn't
> (yet)
> been any specific test case for it.  It was fixed because the RFC
> specifies 0x00
> to be used for padding and nothing else.
>
>
> http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/netinet/tcp_output.c.diff?r1=1.145;r2=1.146
>
> It would be very helpful if you could apply these two patches after each
> other
> to your 7.0 test server and find out together with the affected user(s)
> which
> of these fixes the issue.  If you can please try to test each one with and
> w/o
> the routers firewall enabled.  It is interesting to know whether the NAT
> or
> firewalling part of the router chokes on it.
>
> We've been running with the patches for a few days now, and they seem to
fix the issue. We checked with one previously-affected user, and we haven't
received any reports of problems.

-coda