From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net-next] sctp: sctp_transport_dst_check should check if transport pmtu is dst mtu Date: Sun, 19 Feb 2017 18:19:55 -0500 (EST) Message-ID: <20170219.181955.660651394406915269.davem@davemloft.net> References: <7cbbbf479fddc8b516f87bc6258e775634e84dd6.1487320905.git.lucien.xin@gmail.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linux-sctp@vger.kernel.org, marcelo.leitner@gmail.com, nhorman@tuxdriver.com, vyasevich@gmail.com To: lucien.xin@gmail.com Return-path: Received: from shards.monkeyblade.net ([184.105.139.130]:54756 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751095AbdBSXT5 (ORCPT ); Sun, 19 Feb 2017 18:19:57 -0500 In-Reply-To: <7cbbbf479fddc8b516f87bc6258e775634e84dd6.1487320905.git.lucien.xin@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Xin Long Date: Fri, 17 Feb 2017 16:41:45 +0800 > Now when sending a packet, sctp_transport_dst_check will check if dst > is obsolete by calling ipv4/ip6_dst_check. But they return obsolete > only when adding a new cache, after that when the cache's pmtu is > updated again, it will not trigger transport->dst/pmtu's update. > > It can be reproduced by reducing route's pmtu twice. At the 1st time > client will add a new cache, and transport->pathmtu gets updated as > sctp_transport_dst_check finds it's obsolete. But at the 2nd time, > cache's mtu is updated, sctp client will never send out any packet, > because transport->pmtu has no chance to update. > > This patch is to fix this by also checking if transport pmtu is dst > mtu in sctp_transport_dst_check, so that transport->pmtu can be > updated on time. > > Signed-off-by: Xin Long Applied.