Problem with closing tcp session between cisco and freebsd

[Andre Oppermann]

Zherdev Anatoly wrote:
> 
> On Tue, 16 Mar 2004 10:59:06 +0100
> Andre Oppermann <andre at freebsd.org> wrote:
> 
> > Zherdev Anatoly wrote:
> > >
> > > Hello.
> > >
> > > I have problem with tcp session close between cisco and freebsd
> > > Looks like that it bug in freebsd tcp stack.
> >
> > What version of FreeBSD and Cisco IOS do you run on these machines?
> 
> OOPS. Sorry :(
> 
> FreeBSD 4.9-STABLE cvsupped March 3
> Cisco IOS 12.2.19a ip only Cisco 5300

Do you know when it was working correctly the last time?  Do you have
another machine (4.9R or lower, or 5.2 or 5.C) to test against?  On
March 2 the commit of the TCP segment reassembly queue limiter has
been done but that does not change TCP processing otherwise in any
way.  A month ago the TCP-MD5 stuff has been committed.  A year ago
there have been some NewReno fixes.

So no obvious suspect.  Before digging deep into the code its better
to have some more surrounding information.

-- 
Andre


> >
> > --
> > Andre
> >
> >
> > > CISCO state:
> > >
> > > sh tcp brief
> > > 62935208  CISCO..990    FREEBSD.513 FINWAIT1
> > >
> > > FreeBSD state:
> > >
> > > netstat -an
> > > tcp4   57352      0  FREEBSD.513        CISCO.990       ESTABLISHED
> > >
> > > TCP session from cisco side:
> > >
> > > IP: s=CISCO (local), d=FREEBSD (FastEthernet0), len 41,
> > > sending TCP src=990, dst=513, seq=1411875745, ack=880111139, win=3983 ACK
> > > PSH FIN
> > >
> > > IP: s=FREEBSD (FastEthernet0), d=CISCO (FastEthernet0), len
> > > 40, rcvd 3 TCP src=513, dst=990, seq=880111139, ack=1411875745, win=0 ACK
> > >
> > > IP: s=CISCO (local), d=FREEBSD (FastEthernet0), len 41,
> > > sending TCP src=990, dst=513, seq=1411875745, ack=880111139, win=3983 ACK
> > > PSH FIN
> > >
> > > IP: s=FREEBSD (FastEthernet0), d=CISCO (FastEthernet0), len
> > > 40, rcvd 3 TCP src=513, dst=990, seq=880111139, ack=1411875745, win=0 ACK
> > >
> > > ....
> > >
> > > TCP session from FreeBSD side:
> > >
> > > 12:16:25.426584 IP CISCO.990 > FREEBSD.login: FP 1411875745:1411875746(1) ack 880111139 win 3714
> > >
> > > 12:16:25.426675 IP FREEBSD.login > CISCO.990: . ack 1411875745 win 0
> > >
> > > 12:16:35.121888 IP CISCO.990 > FREEBSD.login: FP 1411875745:1411875746(1) ack 880111139 win 3714
> > >
> > > 12:16:35.121976 IP FREEBSD.login > CISCO.990: . ack 1411875745 win 0
> > >
> > > ....
> > >
> > > CISCO send ACK on FreeBSD pocket and send FIN. FreeBSD send ACK with seq w/o changes win=0 (!) and ack=cisco_seq.Cisco wait ack=cisco_seq+1 on FIN but FreeBSD box don't send this and cisco retransmit FIN.
> > >
> > > --
> > > Zherdev Anatoly.
> > > _______________________________________________
> > > freebsd-net at freebsd.org mailing list
> > > http://lists.freebsd.org/mailman/listinfo/freebsd-net
> > > To unsubscribe, send any mail to "freebsd-net-unsubscribe at freebsd.org"
> >
> >
> 
> --
> Zherdev Anatoly.