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=-6.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,T_DKIMWL_WL_HIGH,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 C681DC282DD for ; Thu, 23 May 2019 19:14:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9464D21872 for ; Thu, 23 May 2019 19:14:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1558638862; bh=uiMZxNZb9jvTsvm1Z471D7qsO+eJO02Umt6u34YKsQ0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=0EGxoWWIwEFrtAjJcj1xTHW7sOaYrPcsEumm2hoYSK0f1BhPlrWO1LGhj0tezWyl6 73l/yPM0o69kSdYVBWhqJ1PZu/hgG/xs/O0Ihx5IwKB8IGcoywehgqNUu7q3MjUGqG 6q6cg0KZiHZPy80Jd0rBG2L95NNYLQIfdWPZbQAI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388745AbfEWTOV (ORCPT ); Thu, 23 May 2019 15:14:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:48266 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388726AbfEWTOS (ORCPT ); Thu, 23 May 2019 15:14:18 -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 F2A092184B; Thu, 23 May 2019 19:14:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1558638857; bh=uiMZxNZb9jvTsvm1Z471D7qsO+eJO02Umt6u34YKsQ0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Gqc8z12ztD9lmKSP9MbuXlU6Fb+HfQhDgEaLN+ESZmqyjIjGmvOa1ivQQN6LGpP6j USxr4nVU9+fAfMbB2MsQITPGhTtmbShFznnxuy1qYwrxb4kh6Jul0olN495+elnJBd m9P6p1NPb1FusjkwRrX210sQ+NG1GFaTzVYKHx3A= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mikael Magnusson , Wei Wang , Martin Lau , Eric Dumazet , "David S. Miller" , David Ahern Subject: [PATCH 4.19 001/114] ipv6: fix src addr routing with the exception table Date: Thu, 23 May 2019 21:05:00 +0200 Message-Id: <20190523181731.560730892@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190523181731.372074275@linuxfoundation.org> References: <20190523181731.372074275@linuxfoundation.org> User-Agent: quilt/0.66 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wei Wang [ Upstream commit 510e2ceda031eed97a7a0f9aad65d271a58b460d ] When inserting route cache into the exception table, the key is generated with both src_addr and dest_addr with src addr routing. However, current logic always assumes the src_addr used to generate the key is a /128 host address. This is not true in the following scenarios: 1. When the route is a gateway route or does not have next hop. (rt6_is_gw_or_nonexthop() == false) 2. When calling ip6_rt_cache_alloc(), saddr is passed in as NULL. This means, when looking for a route cache in the exception table, we have to do the lookup twice: first time with the passed in /128 host address, second time with the src_addr stored in fib6_info. This solves the pmtu discovery issue reported by Mikael Magnusson where a route cache with a lower mtu info is created for a gateway route with src addr. However, the lookup code is not able to find this route cache. Fixes: 2b760fcf5cfb ("ipv6: hook up exception table to store dst cache") Reported-by: Mikael Magnusson Bisected-by: David Ahern Signed-off-by: Wei Wang Cc: Martin Lau Cc: Eric Dumazet Acked-by: Martin KaFai Lau Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv6/route.c | 51 +++++++++++++++++++++++++++------------------------ 1 file changed, 27 insertions(+), 24 deletions(-) --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -110,8 +110,8 @@ static int rt6_fill_node(struct net *net int iif, int type, u32 portid, u32 seq, unsigned int flags); static struct rt6_info *rt6_find_cached_rt(struct fib6_info *rt, - struct in6_addr *daddr, - struct in6_addr *saddr); + const struct in6_addr *daddr, + const struct in6_addr *saddr); #ifdef CONFIG_IPV6_ROUTE_INFO static struct fib6_info *rt6_add_route_info(struct net *net, @@ -1542,31 +1542,44 @@ out: * Caller has to hold rcu_read_lock() */ static struct rt6_info *rt6_find_cached_rt(struct fib6_info *rt, - struct in6_addr *daddr, - struct in6_addr *saddr) + const struct in6_addr *daddr, + const struct in6_addr *saddr) { + const struct in6_addr *src_key = NULL; struct rt6_exception_bucket *bucket; - struct in6_addr *src_key = NULL; struct rt6_exception *rt6_ex; struct rt6_info *res = NULL; - bucket = rcu_dereference(rt->rt6i_exception_bucket); - #ifdef CONFIG_IPV6_SUBTREES /* rt6i_src.plen != 0 indicates rt is in subtree * and exception table is indexed by a hash of * both rt6i_dst and rt6i_src. - * Otherwise, the exception table is indexed by - * a hash of only rt6i_dst. + * However, the src addr used to create the hash + * might not be exactly the passed in saddr which + * is a /128 addr from the flow. + * So we need to use f6i->fib6_src to redo lookup + * if the passed in saddr does not find anything. + * (See the logic in ip6_rt_cache_alloc() on how + * rt->rt6i_src is updated.) */ if (rt->fib6_src.plen) src_key = saddr; +find_ex: #endif + bucket = rcu_dereference(rt->rt6i_exception_bucket); rt6_ex = __rt6_find_exception_rcu(&bucket, daddr, src_key); if (rt6_ex && !rt6_check_expired(rt6_ex->rt6i)) res = rt6_ex->rt6i; +#ifdef CONFIG_IPV6_SUBTREES + /* Use fib6_src as src_key and redo lookup */ + if (!res && src_key && src_key != &rt->fib6_src.addr) { + src_key = &rt->fib6_src.addr; + goto find_ex; + } +#endif + return res; } @@ -2650,10 +2663,8 @@ out: u32 ip6_mtu_from_fib6(struct fib6_info *f6i, struct in6_addr *daddr, struct in6_addr *saddr) { - struct rt6_exception_bucket *bucket; - struct rt6_exception *rt6_ex; - struct in6_addr *src_key; struct inet6_dev *idev; + struct rt6_info *rt; u32 mtu = 0; if (unlikely(fib6_metric_locked(f6i, RTAX_MTU))) { @@ -2662,18 +2673,10 @@ u32 ip6_mtu_from_fib6(struct fib6_info * goto out; } - src_key = NULL; -#ifdef CONFIG_IPV6_SUBTREES - if (f6i->fib6_src.plen) - src_key = saddr; -#endif - - bucket = rcu_dereference(f6i->rt6i_exception_bucket); - rt6_ex = __rt6_find_exception_rcu(&bucket, daddr, src_key); - if (rt6_ex && !rt6_check_expired(rt6_ex->rt6i)) - mtu = dst_metric_raw(&rt6_ex->rt6i->dst, RTAX_MTU); - - if (likely(!mtu)) { + rt = rt6_find_cached_rt(f6i, daddr, saddr); + if (unlikely(rt)) { + mtu = dst_metric_raw(&rt->dst, RTAX_MTU); + } else { struct net_device *dev = fib6_info_nh_dev(f6i); mtu = IPV6_MIN_MTU;