From patchwork Mon Aug 17 15:15:24 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 266385 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=-17.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, 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 DE556C433DF for ; Mon, 17 Aug 2020 16:04:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B8CBA2053B for ; Mon, 17 Aug 2020 16:04:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597680290; bh=hATG7HafjljLdKj1Wt4+pOi/Kd8iH8DCfcjblneNboc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=sjRF9lT8WRUm9LSeWoBYK2ZDtRleyoXX3hjkQ9WIdhJRNxptL6JXwvwTDm35QTzYR u/7tzzmbFxD7gVMBIuwcnUBr6i7M6wzdHXi93XUXoKTzvv3AgzLA7b4PpzkkvYulL6 4xCTlPjKYrTqW/M9Z+tNKBXGgdHlfZxM3zjajFg8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388342AbgHQQEo (ORCPT ); Mon, 17 Aug 2020 12:04:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:52548 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388337AbgHQQEm (ORCPT ); Mon, 17 Aug 2020 12:04:42 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 62EE72053B; Mon, 17 Aug 2020 16:04:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597680281; bh=hATG7HafjljLdKj1Wt4+pOi/Kd8iH8DCfcjblneNboc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LSJQuXF5OpmJDBJh135hTn6XZnYw1SZoKFZ3TDwWwVYGb95QUd14X3I55lPufKA8H 5cNeK8JRuzdxAD3eQd3K+FCcEbPiop7oUszNCxhNM/LdA+rWcHh3YCjOmbSEDpWKeZ vIP4G4A2ze01I+y+kE+R/7GqpVFeqzn7+fVKbM64= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, YangYuxi , Julian Anastasov , Simon Horman , Pablo Neira Ayuso , Sasha Levin Subject: [PATCH 5.4 123/270] ipvs: allow connection reuse for unconfirmed conntrack Date: Mon, 17 Aug 2020 17:15:24 +0200 Message-Id: <20200817143801.896368126@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200817143755.807583758@linuxfoundation.org> References: <20200817143755.807583758@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Julian Anastasov [ Upstream commit f0a5e4d7a594e0fe237d3dfafb069bb82f80f42f ] YangYuxi is reporting that connection reuse is causing one-second delay when SYN hits existing connection in TIME_WAIT state. Such delay was added to give time to expire both the IPVS connection and the corresponding conntrack. This was considered a rare case at that time but it is causing problem for some environments such as Kubernetes. As nf_conntrack_tcp_packet() can decide to release the conntrack in TIME_WAIT state and to replace it with a fresh NEW conntrack, we can use this to allow rescheduling just by tuning our check: if the conntrack is confirmed we can not schedule it to different real server and the one-second delay still applies but if new conntrack was created, we are free to select new real server without any delays. YangYuxi lists some of the problem reports: - One second connection delay in masquerading mode: https://marc.info/?t=151683118100004&r=1&w=2 - IPVS low throughput #70747 https://github.com/kubernetes/kubernetes/issues/70747 - Apache Bench can fill up ipvs service proxy in seconds #544 https://github.com/cloudnativelabs/kube-router/issues/544 - Additional 1s latency in `host -> service IP -> pod` https://github.com/kubernetes/kubernetes/issues/90854 Fixes: f719e3754ee2 ("ipvs: drop first packet to redirect conntrack") Co-developed-by: YangYuxi Signed-off-by: YangYuxi Signed-off-by: Julian Anastasov Reviewed-by: Simon Horman Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin --- include/net/ip_vs.h | 10 ++++------ net/netfilter/ipvs/ip_vs_core.c | 12 +++++++----- 2 files changed, 11 insertions(+), 11 deletions(-) diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h index 078887c8c586a..7c37e3c3b1c79 100644 --- a/include/net/ip_vs.h +++ b/include/net/ip_vs.h @@ -1624,18 +1624,16 @@ static inline void ip_vs_conn_drop_conntrack(struct ip_vs_conn *cp) } #endif /* CONFIG_IP_VS_NFCT */ -/* Really using conntrack? */ -static inline bool ip_vs_conn_uses_conntrack(struct ip_vs_conn *cp, - struct sk_buff *skb) +/* Using old conntrack that can not be redirected to another real server? */ +static inline bool ip_vs_conn_uses_old_conntrack(struct ip_vs_conn *cp, + struct sk_buff *skb) { #ifdef CONFIG_IP_VS_NFCT enum ip_conntrack_info ctinfo; struct nf_conn *ct; - if (!(cp->flags & IP_VS_CONN_F_NFCT)) - return false; ct = nf_ct_get(skb, &ctinfo); - if (ct) + if (ct && nf_ct_is_confirmed(ct)) return true; #endif return false; diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c index 8b80ab794a92b..64a05906cc0e6 100644 --- a/net/netfilter/ipvs/ip_vs_core.c +++ b/net/netfilter/ipvs/ip_vs_core.c @@ -2061,14 +2061,14 @@ ip_vs_in(struct netns_ipvs *ipvs, unsigned int hooknum, struct sk_buff *skb, int conn_reuse_mode = sysctl_conn_reuse_mode(ipvs); if (conn_reuse_mode && !iph.fragoffs && is_new_conn(skb, &iph) && cp) { - bool uses_ct = false, resched = false; + bool old_ct = false, resched = false; if (unlikely(sysctl_expire_nodest_conn(ipvs)) && cp->dest && unlikely(!atomic_read(&cp->dest->weight))) { resched = true; - uses_ct = ip_vs_conn_uses_conntrack(cp, skb); + old_ct = ip_vs_conn_uses_old_conntrack(cp, skb); } else if (is_new_conn_expected(cp, conn_reuse_mode)) { - uses_ct = ip_vs_conn_uses_conntrack(cp, skb); + old_ct = ip_vs_conn_uses_old_conntrack(cp, skb); if (!atomic_read(&cp->n_control)) { resched = true; } else { @@ -2076,15 +2076,17 @@ ip_vs_in(struct netns_ipvs *ipvs, unsigned int hooknum, struct sk_buff *skb, int * that uses conntrack while it is still * referenced by controlled connection(s). */ - resched = !uses_ct; + resched = !old_ct; } } if (resched) { + if (!old_ct) + cp->flags &= ~IP_VS_CONN_F_NFCT; if (!atomic_read(&cp->n_control)) ip_vs_conn_expire_now(cp); __ip_vs_conn_put(cp); - if (uses_ct) + if (old_ct) return NF_DROP; cp = NULL; }