From: kuznet@ms2.inr.ac.ru
To: guol@cs.bu.EDU (Guo Liang)
Cc: linux-kernel@vger.kernel.org
Subject: Re: TCP in TIME_WAIT response to dup FIN
Date: Sat, 2 Feb 2002 22:05:07 +0300 (MSK) [thread overview]
Message-ID: <200202021905.WAA19338@ms2.inr.ac.ru> (raw)
In-Reply-To: <Pine.SOL.4.20.0202021116020.1020-100000@csb.bu.edu> from "Guo, Liang" at Feb 2, 2 07:45:01 pm
Hello!
> > that when tcp socket is in TIME_WAIT state, the default response to a
> > retransmitted FIN packets is to silently drop them. Is this the correct
> > way of implementing TIME_WAIT?
No. Linux 2.2 is not expected to have this bug.
> > active and start sending back FIN-ACKs.
No. time-wait never send FINs, just bare ACK.
> > /* Ack old packets if necessary */
> > if (!after(TCP_SKB_CB(skb)->end_seq, tw->rcv_nxt) &&
> > (len > (th->doff * 4) || th->fin))
> > return TCP_TW_ACK;
> > return 0;
> >
> > Which I suspect contains some bug.
It should responce right. end_seq == rcv_nxt in the case of retransmitted
FIN, len == th->doff*4 but th->fin == 1. So, it returns TCP_TW_ACK.
So, it looks right, I have no idea what happens in your case.
Apparently, you diagnosed problem wrongly. It would be better
if you sent tcpdump of bad session instead.
> > Again, my question is whether 2.2.19 is doing correct things,
Supposed to do. If it does not, alas.
> > that in 2.4.9 and how? Or some alternative milder changes?
Milder change is just to install 2.4. :-)
Alexey
prev parent reply other threads:[~2002-02-02 19:05 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <Pine.SOL.4.20.0202012107260.1020-100000@csb.bu.edu>
2002-02-02 16:21 ` Guo, Liang
2002-02-02 19:05 ` kuznet [this message]
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