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From: Florian Westphal <fw@strlen.de>
To: Matthieu Baerts <matttbe@kernel.org>
Cc: Netfilter Devel <netfilter-devel@vger.kernel.org>,
	Netfilter Coreteam <coreteam@netfilter.org>
Subject: Re: Netfilter: match "tcp option" with the same type present multiple times
Date: Mon, 28 Sep 2026 23:08:35 +0200	[thread overview]
Message-ID: <arrXOOODs-EeMnNC@strlen.de> (raw)
In-Reply-To: <cc29ad91-bb10-4b82-813b-2acea5dab3a7@kernel.org>

Matthieu Baerts <matttbe@kernel.org> wrote:
> Yes, or with a raw payload expression with NFTables.

If you expect identical layout every time, yes, that works too.

> Should there be a note somewhere in the doc about this limitation?
> Because it looks like it will never be possible to match such subtype.

Yes, not without extra code on the kernel side.

> There are other MPTCP suboptions that can be used with DSS, e.g. MP_PRIO
> and MP_FAIL. But also MP_RST that can be used with FAST_CLOSE.

Right.  I did not consider that this stops at first mptcp option
encountered.

> > passes here.
> > Even tried adding 'tcp option timestamp exists...' to the test, also
> > passes.
> 
> Arf, my bad, I still had debugging code, sorry... :/

Phew :-)

  reply	other threads:[~2026-09-28 21:08 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-28 12:13 Netfilter: match "tcp option" with the same type present multiple times Matthieu Baerts
2026-09-28 13:13 ` Florian Westphal
2026-09-28 20:26   ` Matthieu Baerts
2026-09-28 21:08     ` Florian Westphal [this message]
2026-09-28 20:56   ` Fernando Fernandez Mancera
2026-09-28 21:22     ` Florian Westphal
2026-09-28 21:23       ` Fernando Fernandez Mancera
2026-09-28 20:54 ` Fernando Fernandez Mancera
2026-09-28 21:17   ` Fernando Fernandez Mancera
2026-09-28 21:22     ` Matthieu Baerts
2026-09-28 21:52 ` Pablo Neira Ayuso
2026-09-29  9:21   ` Matthieu Baerts
2026-09-29 10:00     ` Pablo Neira Ayuso
2026-09-29 10:40       ` Matthieu Baerts
2026-09-29 12:03         ` Pablo Neira Ayuso
2026-09-30 18:33           ` Matthieu Baerts
2026-10-06 23:29             ` Pablo Neira Ayuso
2026-10-07  8:01               ` Fernando Fernandez Mancera
2026-10-07 10:47                 ` Pablo Neira Ayuso
2026-10-07  8:17               ` Matthieu Baerts
2026-09-28 21:54 ` Jan Engelhardt
2026-09-29  9:34   ` Matthieu Baerts

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