From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 11E8DC433EF for ; Wed, 25 May 2022 07:52:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234319AbiEYHwC (ORCPT ); Wed, 25 May 2022 03:52:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35602 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230202AbiEYHwB (ORCPT ); Wed, 25 May 2022 03:52:01 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF7BA3FBE9 for ; Wed, 25 May 2022 00:52:00 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 92D0CB81CBA for ; Wed, 25 May 2022 07:51:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 045B8C385B8; Wed, 25 May 2022 07:51:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1653465118; bh=X8fhvSba/AuBjjBwZK/suOybf9Q61kPHZ1p8yrZiUCg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=uPCiVlhFtIii1ammefAQVGQ78nDPXbFSqRTFW2n+TX1UqXYgAohC0lxek7LmD0B5K apSVlEw1/XBnp97GzBXq6JygJfrUHWplFFP+p4xHptRvWNkaD8W9/F47Ss4rFTWfs3 jjv7bnjjvqI2MRbvxuOulZnWcc7sChVu9RFhkUpM= Date: Wed, 25 May 2022 09:51:55 +0200 From: Greg KH To: Mat Martineau Cc: stable@vger.kernel.org, sashal@kernel.org, matthieu.baerts@tessares.net, Paolo Abeni , "David S . Miller" Subject: Re: [PATCH] mptcp: Do TCP fallback on early DSS checksum failure Message-ID: References: <20220524181041.19543-1-mathew.j.martineau@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220524181041.19543-1-mathew.j.martineau@linux.intel.com> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Tue, May 24, 2022 at 11:10:41AM -0700, Mat Martineau wrote: > [ Upstream commit ae66fb2ba6c3dcaf8b9612b65aa949a1a4bed150 ] > > RFC 8684 section 3.7 describes several opportunities for a MPTCP > connection to "fall back" to regular TCP early in the connection > process, before it has been confirmed that MPTCP options can be > successfully propagated on all SYN, SYN/ACK, and data packets. If a peer > acknowledges the first received data packet with a regular TCP header > (no MPTCP options), fallback is allowed. > > If the recipient of that first data packet finds a MPTCP DSS checksum > error, this provides an opportunity to fail gracefully with a TCP > fallback rather than resetting the connection (as might happen if a > checksum failure were detected later). > > This commit modifies the checksum failure code to attempt fallback on > the initial subflow of a MPTCP connection, only if it's a failure in the > first data mapping. In cases where the peer initiates the connection, > requests checksums, is the first to send data, and the peer is sending > incorrect checksums (see > https://github.com/multipath-tcp/mptcp_net-next/issues/275), this allows > the connection to proceed as TCP rather than reset. > > Cc: # 5.17.x > Cc: # 5.15.x > Fixes: dd8bcd1768ff ("mptcp: validate the data checksum") > Acked-by: Paolo Abeni > Signed-off-by: Mat Martineau > Signed-off-by: David S. Miller > [mathew.j.martineau: backport: Resolved bitfield conflict in protocol.h] > Signed-off-by: Mat Martineau > --- > > This patch is already in 5.17.10-rc1 and 5.15.42-rc1, but involves a > context dependency on upstream commit 4cf86ae84c71 which I have > requested to be dropped from the stable queues. > > I'm posting this backport without the protocol.h conflict to > (hopefully?) make it easier for the stable maintainers to drop > 4cf86ae84c71. > > For context see https://lore.kernel.org/stable/fa953ec-288f-7715-c6fb-47a222e85270@linux.intel.com/ THanks, will take this after this round of releases. greg k-h