From: David Laight <David.Laight@ACULAB.COM>
To: linux-sctp@vger.kernel.org
Subject: RE: sctp discarding received data chunks
Date: Sun, 11 Oct 2020 15:28:43 +0000 [thread overview]
Message-ID: <645944cb37fa4e41b90b18ff2b5d313d@AcuMS.aculab.com> (raw)
In-Reply-To: <e377e7e2a87e4f078e7a6d82992cfda0@AcuMS.aculab.com>
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WARNING: multiple messages have this Message-ID (diff)
From: David Laight <David.Laight@ACULAB.COM>
To: David Laight <David.Laight@ACULAB.COM>,
'Xin Long' <lucien.xin@gmail.com>
Cc: Andreas Fink <afink@list.fink.org>,
Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>,
Neil Horman <nhorman@tuxdriver.com>,
"linux-sctp@vger.kernel.org" <linux-sctp@vger.kernel.org>
Subject: RE: sctp discarding received data chunks
Date: Sun, 11 Oct 2020 15:28:43 +0000 [thread overview]
Message-ID: <645944cb37fa4e41b90b18ff2b5d313d@AcuMS.aculab.com> (raw)
Message-ID: <20201011152843.xNL4l7G98sorrGyDVe40v_SubqWOT6vO7EbNJXTTRbo@z> (raw)
In-Reply-To: <5af24669b72c4bbb9456b53c397489a4@AcuMS.aculab.com>
...
> > > If I dump out /proc/net/sctp/assocs and look way over to the right
> > > (on the next monitor but 1) there are two columns INS and OUTS.
> > > I've just realised that these are the number of streams.
> > > Now all my connections are loopback - so I see both sockets for each.
> > > So I'd expect the INS to match the OUTS of the peer.
> > > This isn't true.
> > > When the value should be negotiated down the OUTS value is unchanged.
> > > So the kernel is sending packets with illegal stream numbers.
> > > These are acked and then silently discarded.
>
> > did it do addstream reconfig or receive any duplicate COOKIE-ECHO in your case?
>
> Extremely unlikely.
>
> Looking at the latest version of my driver code
> (which I wasn't using) I wrote the following:
>
> * Since the code that negotiates the number of streams got broken
> * in version 5.1 we need to extract the correct value from the
> * internal structures to avoid SCTP sending messages the remote
> * system will discard.
>
> /* stream.outcnt is the value we should be using.
> * But kernels 5.1 to 5.8 fail to reduce it based on the number
> * received from the remote system.
> * So bound here so that transmitted messages don't get discarded. */
> outcnt = asoc->stream.outcnt;
> num_ostreams = asoc->c.sinit_num_ostreams;
>
> I think there was a patch done for 5.9.
> It needs back-porting.
Yes, I wrote the patch.
Applied to net-next.
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/net/sctp/stream.c?id=ab921f3cdbec01c68705a7ade8bec628d541fc2b
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2020-10-11 15:28 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-08 21:46 sctp discarding received data chunks David Laight
2020-10-08 21:46 ` David Laight
2020-10-09 7:24 ` Andreas Fink
2020-10-09 7:24 ` Andreas Fink
2020-10-09 7:57 ` David Laight
2020-10-09 7:57 ` David Laight
2020-10-09 11:13 ` David Laight
2020-10-09 11:13 ` David Laight
2020-10-09 13:03 ` David Laight
2020-10-09 13:03 ` David Laight
2020-10-10 2:35 ` Xin Long
2020-10-10 2:35 ` Xin Long
2020-10-10 15:10 ` David Laight
2020-10-10 15:10 ` David Laight
2020-10-11 8:33 ` Andreas Fink
2020-10-11 8:33 ` Andreas Fink
2020-10-11 15:28 ` David Laight [this message]
2020-10-11 15:28 ` David Laight
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