From patchwork Thu Nov 19 21:23:51 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Duyck X-Patchwork-Id: 328935 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=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED 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 35449C6379F for ; Thu, 19 Nov 2020 21:24:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CCCE720BED for ; Thu, 19 Nov 2020 21:24:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="M+xlC4LZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726311AbgKSVX4 (ORCPT ); Thu, 19 Nov 2020 16:23:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43326 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725887AbgKSVX4 (ORCPT ); Thu, 19 Nov 2020 16:23:56 -0500 Received: from mail-qk1-x741.google.com (mail-qk1-x741.google.com [IPv6:2607:f8b0:4864:20::741]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7955CC0613CF; Thu, 19 Nov 2020 13:23:54 -0800 (PST) Received: by mail-qk1-x741.google.com with SMTP id k4so6908988qko.13; Thu, 19 Nov 2020 13:23:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:from:to:cc:date:message-id:in-reply-to:references :user-agent:mime-version:content-transfer-encoding; bh=rsJB7zlj1ubuXabMIzGnYmJ1xAmzWzPfgMBEPVTYqiw=; b=M+xlC4LZ0W0RBfeQ8bJKTXQ6k4Wk7hm7LybWzFmAL9hXJ5GkrSrBLrDlbzbNsXDqwt jdOcFj5Q4SQq5ohkBCFDDF/aIo2rAiHlKFpck3ljklGkj3dkZkEwYg/Hj8HzrNTDGclZ L9rkMmfnz3ahKXjxCzg8/CHmjd482AkPM0ZNKakx9q2015rMOkiaPZDo8MYKtGAgWh9a DJNFKRcZylV30pLZEe/OwX/8D0LiC4XgFxdwV0DzodgWbt34uW/OLbn0HESX47yEjjk4 qxhyWtTrwuEXGi+yNVvS25kDeDd2vZSve0r5W1SbAC5RtPM6LRABJG4lVJBeapE7obXd UVsA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:from:to:cc:date:message-id:in-reply-to :references:user-agent:mime-version:content-transfer-encoding; bh=rsJB7zlj1ubuXabMIzGnYmJ1xAmzWzPfgMBEPVTYqiw=; b=DSi387vXajWvy8V+AjWbwMhv+7si64tDOYAqLZzV+uhtKkN0H9lKMRO/pEu0CHONCA PpdwtPyOFOcTd7I3A26kDRpG+8xMRrfp7kGfvV5ekehZQGkK9kbI3lM4spEyoeWXP6Hg FimX8++8q7sAoQY2Zh5gxi4D0xlvamqrA3y5fA0AVk9EVpVc5ZPew09ZvlAotzB/+tH8 eg5huGh13q/lHfPcTLpmQ19EPaarb43q8OzdB5QSooJ0OXrVKaAgm2ktGjDo2neI+Hii Iv9cZ1t1SBfg5yOpit9GDT8X8an7sqtiHJvEXyxPUV+xe5Jb9AN9VqQ0CcgQrXIlZ8if uKlw== X-Gm-Message-State: AOAM533z1fCwkf/aFFFRfywHor4wK5CvMP5ql9aRFG90H09HHSbUqQLi xluTkGYsn8irp4O+Buc+kNdRXKU3vvnEug== X-Google-Smtp-Source: ABdhPJxZLSkvv9TBTCU9BtisX+3eGnv9olK8d5wylR+7gk3o9am0gce+0Ms+ziup2x2RwSOr0cixQQ== X-Received: by 2002:a37:a855:: with SMTP id r82mr12429026qke.132.1605821033465; Thu, 19 Nov 2020 13:23:53 -0800 (PST) Received: from localhost.localdomain ([2001:470:b:9c3:9e5c:8eff:fe4f:f2d0]) by smtp.gmail.com with ESMTPSA id 21sm796088qkv.78.2020.11.19.13.23.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 Nov 2020 13:23:52 -0800 (PST) Subject: [net PATCH 1/2] tcp: Allow full IP tos/IPv6 tclass to be reflected in L3 header From: Alexander Duyck To: netdev@vger.kernel.org Cc: bpf@vger.kernel.org, daniel@iogearbox.net, kafai@fb.com, kernel-team@fb.com, edumazet@google.com, brakmo@fb.com, alexanderduyck@fb.com, weiwan@google.com Date: Thu, 19 Nov 2020 13:23:51 -0800 Message-ID: <160582103106.66684.9841738004971200231.stgit@localhost.localdomain> In-Reply-To: <160582070138.66684.11785214534154816097.stgit@localhost.localdomain> References: <160582070138.66684.11785214534154816097.stgit@localhost.localdomain> User-Agent: StGit/0.23 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Alexander Duyck An issue was recently found where DCTCP SYN/ACK packets did not have the ECT bit set in the L3 header. A bit of code review found that the recent change referenced below had gone though and added a mask that prevented the ECN bits from being populated in the L3 header. This patch addresses that by rolling back the mask so that it is only applied to the flags coming from the incoming TCP request instead of applying it to the socket tos/tclass field. Doing this the ECT bits were restored in the SYN/ACK packets in my testing. One thing that is not addressed by this patch set is the fact that tcp_reflect_tos appears to be incompatible with ECN based congestion avoidance algorithms. At a minimum the feature should likely be documented which it currently isn't. Fixes: ac8f1710c12b ("tcp: reflect tos value received in SYN to the socket") Signed-off-by: Alexander Duyck Acked-by: Wei Wang --- net/ipv4/tcp_ipv4.c | 5 +++-- net/ipv6/tcp_ipv6.c | 6 +++--- 2 files changed, 6 insertions(+), 5 deletions(-) diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index c2d5132c523c..c5f8b686aa82 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -981,7 +981,8 @@ static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst, skb = tcp_make_synack(sk, dst, req, foc, synack_type, syn_skb); tos = sock_net(sk)->ipv4.sysctl_tcp_reflect_tos ? - tcp_rsk(req)->syn_tos : inet_sk(sk)->tos; + tcp_rsk(req)->syn_tos & ~INET_ECN_MASK : + inet_sk(sk)->tos; if (skb) { __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr); @@ -990,7 +991,7 @@ static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst, err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr, ireq->ir_rmt_addr, rcu_dereference(ireq->ireq_opt), - tos & ~INET_ECN_MASK); + tos); rcu_read_unlock(); err = net_xmit_eval(err); } diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 8db59f4e5f13..3d49e8d0afee 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -530,12 +530,12 @@ static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst, rcu_read_lock(); opt = ireq->ipv6_opt; tclass = sock_net(sk)->ipv4.sysctl_tcp_reflect_tos ? - tcp_rsk(req)->syn_tos : np->tclass; + tcp_rsk(req)->syn_tos & ~INET_ECN_MASK : + np->tclass; if (!opt) opt = rcu_dereference(np->opt); err = ip6_xmit(sk, skb, fl6, sk->sk_mark, opt, - tclass & ~INET_ECN_MASK, - sk->sk_priority); + tclass, sk->sk_priority); rcu_read_unlock(); err = net_xmit_eval(err); }