From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 087E31FBA for ; Tue, 3 Oct 2023 11:07:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C4B01C433C7; Tue, 3 Oct 2023 11:07:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1696331274; bh=TKTRuzbZsAq7tIREecfAg4xCUdtaJQmSFDV+y5mv320=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=NXcJOda5aQVaKB8JPkmr685VZQx3u8jEYb2yWvI+dJrpiHuCs9sMlJbQgZ0sROc0W M5MhlSBxigyQLIISmMrHuRCFPPoZGSXjp4ir9b0VjOTxnpqXdLlzxgG43T0MGL/HD5 7MomRAQEbuOvZjDRwVvQHRNDw1cs2eW3hIeogH0TjuQSLYsXOwUGUX5n2klFVdCXbt WNFyobDIxZ32L90aYOeewFD1h2vVx/aym62FAYzNEfQS4LCow243rKaS4UFfj6hKPm ICxrieF2rLJT4UC/gb4uaURo6H99HXknZFkhrODddKmCfl5PdAEpJNvZX7GHJREldT B4COIW97Upuaw== Date: Tue, 3 Oct 2023 13:07:50 +0200 From: Simon Horman To: Xin Long Cc: network dev , linux-sctp@vger.kernel.org, davem@davemloft.net, kuba@kernel.org, Eric Dumazet , Paolo Abeni , Marcelo Ricardo Leitner Subject: Re: [PATCH net] sctp: update transport state when processing a dupcook packet Message-ID: References: Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Sun, Oct 01, 2023 at 10:58:45AM -0400, Xin Long wrote: > During the 4-way handshake, the transport's state is set to ACTIVE in > sctp_process_init() when processing INIT_ACK chunk on client or > COOKIE_ECHO chunk on server. > > In the collision scenario below: > > 192.168.1.2 > 192.168.1.1: sctp (1) [INIT] [init tag: 3922216408] > 192.168.1.1 > 192.168.1.2: sctp (1) [INIT] [init tag: 144230885] > 192.168.1.2 > 192.168.1.1: sctp (1) [INIT ACK] [init tag: 3922216408] > 192.168.1.1 > 192.168.1.2: sctp (1) [COOKIE ECHO] > 192.168.1.2 > 192.168.1.1: sctp (1) [COOKIE ACK] > 192.168.1.1 > 192.168.1.2: sctp (1) [INIT ACK] [init tag: 3914796021] > > when processing COOKIE_ECHO on 192.168.1.2, as it's in COOKIE_WAIT state, > sctp_sf_do_dupcook_b() is called by sctp_sf_do_5_2_4_dupcook() where it > creates a new association and sets its transport to ACTIVE then updates > to the old association in sctp_assoc_update(). > > However, in sctp_assoc_update(), it will skip the transport update if it > finds a transport with the same ipaddr already existing in the old asoc, > and this causes the old asoc's transport state not to move to ACTIVE > after the handshake. > > This means if DATA retransmission happens at this moment, it won't be able > to enter PF state because of the check 'transport->state == SCTP_ACTIVE' > in sctp_do_8_2_transport_strike(). > > This patch fixes it by updating the transport in sctp_assoc_update() with > sctp_assoc_add_peer() where it updates the transport state if there is > already a transport with the same ipaddr exists in the old asoc. Hi Xin Long, I wonder if this warrants a fixes tag, and if so, perhaps: Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") > Signed-off-by: Xin Long Reviewed-by: Simon Horman