From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net] net/ipv6: Only update MTU metric if it set Date: Sun, 02 Sep 2018 14:04:40 -0700 (PDT) Message-ID: <20180902.140440.1729935905351650374.davem@davemloft.net> References: <20180830211543.27111-1-dsahern@kernel.org> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, medhefgo@web.de, dsahern@gmail.com To: dsahern@kernel.org Return-path: Received: from shards.monkeyblade.net ([23.128.96.9]:34916 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726421AbeICBVq (ORCPT ); Sun, 2 Sep 2018 21:21:46 -0400 In-Reply-To: <20180830211543.27111-1-dsahern@kernel.org> Sender: netdev-owner@vger.kernel.org List-ID: From: dsahern@kernel.org Date: Thu, 30 Aug 2018 14:15:43 -0700 > From: David Ahern > > Jan reported a regression after an update to 4.18.5. In this case ipv6 > default route is setup by systemd-networkd based on data from an RA. The > RA contains an MTU of 1492 which is used when the route is first inserted > but then systemd-networkd pushes down updates to the default route > without the mtu set. > > Prior to the change to fib6_info, metrics such as MTU were held in the > dst_entry and rt6i_pmtu in rt6_info contained an update to the mtu if > any. ip6_mtu would look at rt6i_pmtu first and use it if set. If not, > the value from the metrics is used if it is set and finally falling > back to the idev value. > > After the fib6_info change metrics are contained in the fib6_info struct > and there is no equivalent to rt6i_pmtu. To maintain consistency with > the old behavior the new code should only reset the MTU in the metrics > if the route update has it set. > > Fixes: d4ead6b34b67 ("net/ipv6: move metrics from dst to rt6_info") > Reported-by: Jan Janssen > Signed-off-by: David Ahern Applied and queued up for -stable, thanks David.