From patchwork Thu Mar 4 08:57:53 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ido Schimmel X-Patchwork-Id: 393372 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=-16.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, 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 85574C433E6 for ; Thu, 4 Mar 2021 09:00:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6AA7864F23 for ; Thu, 4 Mar 2021 09:00:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237281AbhCDI7n (ORCPT ); Thu, 4 Mar 2021 03:59:43 -0500 Received: from out3-smtp.messagingengine.com ([66.111.4.27]:47243 "EHLO out3-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237261AbhCDI7d (ORCPT ); Thu, 4 Mar 2021 03:59:33 -0500 Received: from compute3.internal (compute3.nyi.internal [10.202.2.43]) by mailout.nyi.internal (Postfix) with ESMTP id 5446F5C0103; Thu, 4 Mar 2021 03:58:28 -0500 (EST) Received: from mailfrontend2 ([10.202.2.163]) by compute3.internal (MEProxy); Thu, 04 Mar 2021 03:58:28 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:date:from :in-reply-to:message-id:mime-version:references:subject:to :x-me-proxy:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s= fm2; bh=7ES+NblSBDb5mo4eEVRyWQtGnBK0VISFkGKxCVXpH2I=; b=twE/XJUH SMP/f0aIbTWiJ2RPx6rFr7W9yITYbUglx5n/B9X3noGEzKBtZyBRpUYSjUrI6Umz pGo2PfOwagCVoqZ4cLRuJLcBxBu8+rrNj5j91vagClCCD06favhyzR7jM3ivWGF4 nktSWn45sR0DnaVEL0m0vfF0/dvQaTa1VNGSYrMf9mo/Kpsa1rz5G22ez+XUoVM1 a1pOGROLsJO9+rzh62ZwTrLGX4MULZoreo3EyHx4nrm/XroSdpjyVgLidnXsGms8 TwUCcSLtZWuu5zWOvr61edKFM32VysADiCdcH5sVF/VEBanluxkUJJRpVOhJhEEZ YdfTZ+Swm4RfoA== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduledruddtfedguddugecutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfgh necuuegrihhlohhuthemuceftddtnecunecujfgurhephffvufffkffojghfggfgsedtke ertdertddtnecuhfhrohhmpefkughoucfutghhihhmmhgvlhcuoehiughoshgthhesihgu ohhstghhrdhorhhgqeenucggtffrrghtthgvrhhnpeduteeiveffffevleekleejffekhf ekhefgtdfftefhledvjefggfehgfevjeekhfenucfkphepkeegrddvvdelrdduheefrdeg geenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhrohhmpehiug hoshgthhesihguohhstghhrdhorhhg X-ME-Proxy: Received: from shredder.mellanox.com (igld-84-229-153-44.inter.net.il [84.229.153.44]) by mail.messagingengine.com (Postfix) with ESMTPA id 3F5CA1080054; Thu, 4 Mar 2021 03:58:26 -0500 (EST) From: Ido Schimmel To: netdev@vger.kernel.org Cc: davem@davemloft.net, kuba@kernel.org, dsahern@gmail.com, roopa@nvidia.com, sharpd@nvidia.com, mlxsw@nvidia.com, Ido Schimmel Subject: [PATCH net 1/2] nexthop: Do not flush blackhole nexthops when loopback goes down Date: Thu, 4 Mar 2021 10:57:53 +0200 Message-Id: <20210304085754.1929848-2-idosch@idosch.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210304085754.1929848-1-idosch@idosch.org> References: <20210304085754.1929848-1-idosch@idosch.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Ido Schimmel As far as user space is concerned, blackhole nexthops do not have a nexthop device and therefore should not be affected by the administrative or carrier state of any netdev. However, when the loopback netdev goes down all the blackhole nexthops are flushed. This happens because internally the kernel associates blackhole nexthops with the loopback netdev. This behavior is both confusing to those not familiar with kernel internals and also diverges from the legacy API where blackhole IPv4 routes are not flushed when the loopback netdev goes down: # ip route add blackhole 198.51.100.0/24 # ip link set dev lo down # ip route show 198.51.100.0/24 blackhole 198.51.100.0/24 Blackhole IPv6 routes are flushed, but at least user space knows that they are associated with the loopback netdev: # ip -6 route show 2001:db8:1::/64 blackhole 2001:db8:1::/64 dev lo metric 1024 pref medium Fix this by only flushing blackhole nexthops when the loopback netdev is unregistered. Fixes: ab84be7e54fc ("net: Initial nexthop code") Signed-off-by: Ido Schimmel Reported-by: Donald Sharp Reviewed-by: David Ahern --- net/ipv4/nexthop.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c index f1c6cbdb9e43..743777bce179 100644 --- a/net/ipv4/nexthop.c +++ b/net/ipv4/nexthop.c @@ -1399,7 +1399,7 @@ static int insert_nexthop(struct net *net, struct nexthop *new_nh, /* rtnl */ /* remove all nexthops tied to a device being deleted */ -static void nexthop_flush_dev(struct net_device *dev) +static void nexthop_flush_dev(struct net_device *dev, unsigned long event) { unsigned int hash = nh_dev_hashfn(dev->ifindex); struct net *net = dev_net(dev); @@ -1411,6 +1411,10 @@ static void nexthop_flush_dev(struct net_device *dev) if (nhi->fib_nhc.nhc_dev != dev) continue; + if (nhi->reject_nh && + (event == NETDEV_DOWN || event == NETDEV_CHANGE)) + continue; + remove_nexthop(net, nhi->nh_parent, NULL); } } @@ -2189,11 +2193,11 @@ static int nh_netdev_event(struct notifier_block *this, switch (event) { case NETDEV_DOWN: case NETDEV_UNREGISTER: - nexthop_flush_dev(dev); + nexthop_flush_dev(dev, event); break; case NETDEV_CHANGE: if (!(dev_get_flags(dev) & (IFF_RUNNING | IFF_LOWER_UP))) - nexthop_flush_dev(dev); + nexthop_flush_dev(dev, event); break; case NETDEV_CHANGEMTU: info_ext = ptr;