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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 D5FE8C4363A for ; Tue, 27 Oct 2020 17:10:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8A3FD21D42 for ; Tue, 27 Oct 2020 17:10:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603818640; bh=1vzlWKVIFhdDYQeiCTaVEr3glNUUpWGJ7xCLr2S38a4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=q1b9CLxSrZw9aPIemaMfzJWkYQetIVpekEnYthV7LD6Zvqi8PhX1Jz4amc0oEwrPv ZVckEx2AectjXcQZGZWF8gqcZHOgJXWWebz2Z1TDgO7ayukugReDE/gHY1X+KVwnP0 KBeOvBV3PdUhPCt3th3E3uSQGqvIkUhq4JmHTZtQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1786697AbgJ0O7z (ORCPT ); Tue, 27 Oct 2020 10:59:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:49478 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1766585AbgJ0OtW (ORCPT ); Tue, 27 Oct 2020 10:49:22 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 80FDE207DE; Tue, 27 Oct 2020 14:49:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603810162; bh=1vzlWKVIFhdDYQeiCTaVEr3glNUUpWGJ7xCLr2S38a4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OUtdFqaZVOHXdIv5QFrFwj8dwTAhV2822G1ENg6HGaMJz5ixkxjMAPOMOf1ePus59 FD6h7Qn3tP4TNytHrOADeWHyyle25gxbP/K9Mk0JRghMkIhzTOQcmSPFVN8dGkTGQX BUUvId3QRuv5LPcrsbAYHKOIklQ5Jb33THzljCeQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Paolo Abeni , Davide Caratti , Mat Martineau , Jakub Kicinski Subject: [PATCH 5.8 011/633] net: mptcp: make DACK4/DACK8 usage consistent among all subflows Date: Tue, 27 Oct 2020 14:45:54 +0100 Message-Id: <20201027135523.213700454@linuxfoundation.org> X-Mailer: git-send-email 2.29.1 In-Reply-To: <20201027135522.655719020@linuxfoundation.org> References: <20201027135522.655719020@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Davide Caratti [ Upstream commit 37198e93ced70733f0b993dff28b7c33857e254f ] using packetdrill it's possible to observe the same MPTCP DSN being acked by different subflows with DACK4 and DACK8. This is in contrast with what specified in RFC8684 ยง3.3.2: if an MPTCP endpoint transmits a 64-bit wide DSN, it MUST be acknowledged with a 64-bit wide DACK. Fix 'use_64bit_ack' variable to make it a property of MPTCP sockets, not TCP subflows. Fixes: a0c1d0eafd1e ("mptcp: Use 32-bit DATA_ACK when possible") Acked-by: Paolo Abeni Signed-off-by: Davide Caratti Reviewed-by: Mat Martineau Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/mptcp/options.c | 2 +- net/mptcp/protocol.h | 2 +- net/mptcp/subflow.c | 3 +-- 3 files changed, 3 insertions(+), 4 deletions(-) --- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -517,7 +517,7 @@ static bool mptcp_established_options_ds return ret; } - if (subflow->use_64bit_ack) { + if (READ_ONCE(msk->use_64bit_ack)) { ack_size = TCPOLEN_MPTCP_DSS_ACK64; opts->ext_copy.data_ack = msk->ack_seq; opts->ext_copy.ack64 = 1; --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -199,6 +199,7 @@ struct mptcp_sock { u32 token; unsigned long flags; bool can_ack; + bool use_64bit_ack; /* Set when we received a 64-bit DSN */ spinlock_t join_list_lock; struct work_struct work; struct list_head conn_list; @@ -285,7 +286,6 @@ struct mptcp_subflow_context { data_avail : 1, rx_eof : 1, data_fin_tx_enable : 1, - use_64bit_ack : 1, /* Set when we received a 64-bit DSN */ can_ack : 1; /* only after processing the remote a key */ u64 data_fin_tx_seq; u32 remote_nonce; --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -682,12 +682,11 @@ static enum mapping_status get_mapping_s if (!mpext->dsn64) { map_seq = expand_seq(subflow->map_seq, subflow->map_data_len, mpext->data_seq); - subflow->use_64bit_ack = 0; pr_debug("expanded seq=%llu", subflow->map_seq); } else { map_seq = mpext->data_seq; - subflow->use_64bit_ack = 1; } + WRITE_ONCE(mptcp_sk(subflow->conn)->use_64bit_ack, !!mpext->dsn64); if (subflow->map_valid) { /* Allow replacing only with an identical map */