Re: Segment failed SYNCOOKIE?

Steve Kargl wrote:
> On Wed, May 30, 2007 at 02:40:04PM +0200, Andre Oppermann wrote:
>> I have committed further changes and logging to tcp_input() that
>> will give more insight into this.  Please update to the latest
>> current and report the new log messages.
>>
> 
> Andre,
> 
> I have 
>  src/sys/netinet/tcp_syncache.c,v 1.120 2007/05/28 23:27:44 andre Exp $
> which is giving me
> 
> 
> May 30 12:20:07 node13 kernel: bge0: watchdog timeout -- resetting
> May 30 12:20:07 node13 kernel: bge0: link state changed to DOWN
> May 30 12:20:09 node13 kernel: bge0: link state changed to UP
> May 30 12:20:53 node13 kernel: TCP: [192.168.0.13]:55626 to [192.168.0.13]:59148 tcpflags 0x10<ACK>; syncache_expand: Segment failed SYNCOOKIE authentication, segment rejected (probably spoofed)
> May 30 12:20:53 node13 kernel: TCP: [192.168.0.11]:62391 to [192.168.0.13]:50827 tcpflags 0x11<FIN,ACK>; syncache_expand: Segment failed SYNCOOKIE authentication, segment rejected (probably spoofed)
> May 30 12:20:54 node13 kernel: TCP: [192.168.0.12]:63318 to [192.168.0.13]:55624 tcpflags 0x10<ACK>; syncache_expand: Segment failed SYNCOOKIE authentication, segment rejected (probably spoofed)

Our TCP has a bug where it closes a socket and tcpcb too fast and
follow-up replies from the remote host may then hit the listen
socket giving these artifacts.  I have a large TCP cleanup/rewrite
upcoming that fixes these issues.

> I don't know if the watchdog timeout is a symptom or cause of the
> SYNCOOKIE problem.

In theory this is not related.  However if it *only* happens shortly
after a bge0 watchdog timeout then there may be a relation.

> Note, this is an openmpi app that is using the Message Passing Interface
> to communicate between processes.

Does the openmpi application or the openmpi library raise any errors?

-- 
Andre