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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 493FCC3F2D7 for ; Fri, 6 Mar 2020 05:35:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 288E52072D for ; Fri, 6 Mar 2020 05:35:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726257AbgCFFfQ (ORCPT ); Fri, 6 Mar 2020 00:35:16 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:59678 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725280AbgCFFfP (ORCPT ); Fri, 6 Mar 2020 00:35:15 -0500 Received: from localhost (unknown [IPv6:2601:601:9f00:477::3d5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 2123715ADABDD; Thu, 5 Mar 2020 21:35:15 -0800 (PST) Date: Thu, 05 Mar 2020 21:35:14 -0800 (PST) Message-Id: <20200305.213514.1337555425416659597.davem@davemloft.net> To: pabeni@redhat.com Cc: netdev@vger.kernel.org, mathew.j.martineau@linux.intel.com, matthieu.baerts@tessares.net, cpaasch@apple.com Subject: Re: [PATCH net v2] mptcp: always include dack if possible. From: David Miller In-Reply-To: References: X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Thu, 05 Mar 2020 21:35:15 -0800 (PST) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Paolo Abeni Date: Wed, 4 Mar 2020 16:51:07 +0100 > Currently passive MPTCP socket can skip including the DACK > option - if the peer sends data before accept() completes. > > The above happens because the msk 'can_ack' flag is set > only after the accept() call. > > Such missing DACK option may cause - as per RFC spec - > unwanted fallback to TCP. > > This change addresses the issue using the key material > available in the current subflow, if any, to create a suitable > dack option when msk ack seq is not yet available. > > v1 -> v2: > - adavance the generated ack after the initial MPC packet > > Fixes: d22f4988ffec ("mptcp: process MP_CAPABLE data option") > Signed-off-by: Paolo Abeni Applied, thank you.