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=-23.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 95A32C49EA2 for ; Tue, 8 Jun 2021 19:13:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7A094613BC for ; Tue, 8 Jun 2021 19:13:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238534AbhFHTPO (ORCPT ); Tue, 8 Jun 2021 15:15:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:39970 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237376AbhFHTE6 (ORCPT ); Tue, 8 Jun 2021 15:04:58 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5CE62613CA; Tue, 8 Jun 2021 18:46:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1623177962; bh=hj6mXvnoMal4PRcF2xTdllekSdclgOAcdrlzJ429Zv8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fgLmCBGQHx2g9XwYz7y5hhLVa29tkDPEIpXALruAMv+Dl3qcvn3acJ0K+Ducl5jAl z+5zVLHXjsDbGvBzbqeFQ2g3nOXX3k0PP3WThx5EbcT4GBhW3JwNX9UQb8M7mu3Mfc SKNXHcc8FAlvbBLH6RztYmDtCZJ72TWF2jokpKtU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Matthieu Baerts , Paolo Abeni , Mat Martineau , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.12 026/161] mptcp: do not reset MP_CAPABLE subflow on mapping errors Date: Tue, 8 Jun 2021 20:25:56 +0200 Message-Id: <20210608175946.334186622@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210608175945.476074951@linuxfoundation.org> References: <20210608175945.476074951@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: Paolo Abeni [ Upstream commit dea2b1ea9c705c5ba351a9174403fd83dbb68fc3 ] When some mapping related errors occurs we close the main MPC subflow with a RST. We should instead fallback gracefully to TCP, and do the reset only for MPJ subflows. Fixes: d22f4988ffec ("mptcp: process MP_CAPABLE data option") Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/192 Reported-by: Matthieu Baerts Signed-off-by: Paolo Abeni Signed-off-by: Mat Martineau Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/mptcp/subflow.c | 59 +++++++++++++++++++++++---------------------- 1 file changed, 30 insertions(+), 29 deletions(-) diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 8878317b4386..8425cd393bf3 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -984,22 +984,11 @@ static bool subflow_check_data_avail(struct sock *ssk) u64 old_ack; status = get_mapping_status(ssk, msk); - pr_debug("msk=%p ssk=%p status=%d", msk, ssk, status); - if (status == MAPPING_INVALID) { - ssk->sk_err = EBADMSG; - goto fatal; - } - if (status == MAPPING_DUMMY) { - __mptcp_do_fallback(msk); - skb = skb_peek(&ssk->sk_receive_queue); - subflow->map_valid = 1; - subflow->map_seq = READ_ONCE(msk->ack_seq); - subflow->map_data_len = skb->len; - subflow->map_subflow_seq = tcp_sk(ssk)->copied_seq - - subflow->ssn_offset; - subflow->data_avail = MPTCP_SUBFLOW_DATA_AVAIL; - return true; - } + if (unlikely(status == MAPPING_INVALID)) + goto fallback; + + if (unlikely(status == MAPPING_DUMMY)) + goto fallback; if (status != MAPPING_OK) goto no_data; @@ -1012,10 +1001,8 @@ static bool subflow_check_data_avail(struct sock *ssk) * MP_CAPABLE-based mapping */ if (unlikely(!READ_ONCE(msk->can_ack))) { - if (!subflow->mpc_map) { - ssk->sk_err = EBADMSG; - goto fatal; - } + if (!subflow->mpc_map) + goto fallback; WRITE_ONCE(msk->remote_key, subflow->remote_key); WRITE_ONCE(msk->ack_seq, subflow->map_seq); WRITE_ONCE(msk->can_ack, true); @@ -1043,15 +1030,29 @@ static bool subflow_check_data_avail(struct sock *ssk) no_data: subflow_sched_work_if_closed(msk, ssk); return false; -fatal: - /* fatal protocol error, close the socket */ - /* This barrier is coupled with smp_rmb() in tcp_poll() */ - smp_wmb(); - ssk->sk_error_report(ssk); - tcp_set_state(ssk, TCP_CLOSE); - tcp_send_active_reset(ssk, GFP_ATOMIC); - subflow->data_avail = 0; - return false; + +fallback: + /* RFC 8684 section 3.7. */ + if (subflow->mp_join || subflow->fully_established) { + /* fatal protocol error, close the socket. + * subflow_error_report() will introduce the appropriate barriers + */ + ssk->sk_err = EBADMSG; + ssk->sk_error_report(ssk); + tcp_set_state(ssk, TCP_CLOSE); + tcp_send_active_reset(ssk, GFP_ATOMIC); + subflow->data_avail = 0; + return false; + } + + __mptcp_do_fallback(msk); + skb = skb_peek(&ssk->sk_receive_queue); + subflow->map_valid = 1; + subflow->map_seq = READ_ONCE(msk->ack_seq); + subflow->map_data_len = skb->len; + subflow->map_subflow_seq = tcp_sk(ssk)->copied_seq - subflow->ssn_offset; + subflow->data_avail = MPTCP_SUBFLOW_DATA_AVAIL; + return true; } bool mptcp_subflow_data_available(struct sock *sk) -- 2.30.2