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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 6CA19C282CE for ; Tue, 4 Jun 2019 14:47:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 46CF120874 for ; Tue, 4 Jun 2019 14:47:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727727AbfFDOry (ORCPT ); Tue, 4 Jun 2019 10:47:54 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]:42318 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727545AbfFDOrx (ORCPT ); Tue, 4 Jun 2019 10:47:53 -0400 Received: from DGGEMS414-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id BA6526D2F651EA5B57BA; Tue, 4 Jun 2019 22:47:50 +0800 (CST) Received: from localhost.localdomain.localdomain (10.175.113.25) by DGGEMS414-HUB.china.huawei.com (10.3.19.214) with Microsoft SMTP Server id 14.3.439.0; Tue, 4 Jun 2019 22:47:42 +0800 From: Mao Wenan To: , CC: , , Mao Wenan Subject: [PATCH net] tcp: avoid creating multiple req socks with the same tuples Date: Tue, 4 Jun 2019 22:55:43 +0800 Message-ID: <20190604145543.61624-1-maowenan@huawei.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.113.25] X-CFilter-Loop: Reflected Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org There is one issue about bonding mode BOND_MODE_BROADCAST, and two slaves with diffierent affinity, so packets will be handled by different cpu. These are two pre-conditions in this case. When two slaves receive the same syn packets at the same time, two request sock(reqsk) will be created if below situation happens: 1. syn1 arrived tcp_conn_request, create reqsk1 and have not yet called inet_csk_reqsk_queue_hash_add. 2. syn2 arrived tcp_v4_rcv, it goes to tcp_conn_request and create reqsk2 because it can't find reqsk1 in the __inet_lookup_skb. Then reqsk1 and reqsk2 are added to establish hash table, and two synack with different seq(seq1 and seq2) are sent to client, then tcp ack arrived and will be processed in tcp_v4_rcv and tcp_check_req, if __inet_lookup_skb find the reqsk2, and tcp ack packet is ack_seq is seq1, it will be failed after checking: TCP_SKB_CB(skb)->ack_seq != tcp_rsk(req)->snt_isn + 1) and then tcp rst will be sent to client and close the connection. To fix this, do lookup before calling inet_csk_reqsk_queue_hash_add to add reqsk2 to hash table, if it finds the existed reqsk1 with the same five tuples, it removes reqsk2 and does not send synack to client. Signed-off-by: Mao Wenan --- net/ipv4/tcp_input.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 08a477e74cf3..c75eeb1fe098 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -6569,6 +6569,15 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops, bh_unlock_sock(fastopen_sk); sock_put(fastopen_sk); } else { + struct sock *sk1 = req_to_sk(req); + struct sock *sk2 = NULL; + sk2 = __inet_lookup_established(sock_net(sk1), &tcp_hashinfo, + sk1->sk_daddr, sk1->sk_dport, + sk1->sk_rcv_saddr, sk1->sk_num, + inet_iif(skb),inet_sdif(skb)); + if (sk2 != NULL) + goto drop_and_release; + tcp_rsk(req)->tfo_listener = false; if (!want_cookie) inet_csk_reqsk_queue_hash_add(sk, req, -- 2.20.1