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=-4.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 CCF56C433E0 for ; Tue, 4 Aug 2020 01:25:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D2DF32086A for ; Tue, 4 Aug 2020 01:25:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729146AbgHDBZ1 (ORCPT ); Mon, 3 Aug 2020 21:25:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49694 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726276AbgHDBZ1 (ORCPT ); Mon, 3 Aug 2020 21:25:27 -0400 Received: from shards.monkeyblade.net (shards.monkeyblade.net [IPv6:2620:137:e000::1:9]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 95911C06174A for ; Mon, 3 Aug 2020 18:25:27 -0700 (PDT) Received: from localhost (unknown [IPv6:2601:601:9f00:477::3d5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 3B1AC1278B070; Mon, 3 Aug 2020 18:08:41 -0700 (PDT) Date: Mon, 03 Aug 2020 18:25:26 -0700 (PDT) Message-Id: <20200803.182526.342368013137626191.davem@davemloft.net> To: sbrivio@redhat.com Cc: fw@strlen.de, dsahern@gmail.com, aconole@redhat.com, nusiddiq@redhat.com, kuba@kernel.org, pshelar@ovn.org, roopa@cumulusnetworks.com, nikolay@cumulusnetworks.com, lu@pplo.net, netdev@vger.kernel.org Subject: Re: [PATCH net-next 0/6] Support PMTU discovery with bridged UDP tunnels From: David Miller In-Reply-To: References: X-Mailer: Mew version 6.8 on Emacs 26.3 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Mon, 03 Aug 2020 18:08:41 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Stefano Brivio Date: Mon, 3 Aug 2020 22:52:08 +0200 > Currently, PMTU discovery for UDP tunnels only works if packets are > routed to the encapsulating interfaces, not bridged. > > This results from the fact that we generally don't have valid routes > to the senders we can use to relay ICMP and ICMPv6 errors, and makes > PMTU discovery completely non-functional for VXLAN and GENEVE ports of > both regular bridges and Open vSwitch instances. > > If the sender is local, and packets are forwarded to the port by a > regular bridge, all it takes is to generate a corresponding route > exception on the encapsulating device. The bridge then finds the route > exception carrying the PMTU value estimate as it forwards frames, and > relays ICMP messages back to the socket of the local sender. Patch 1/6 > fixes this case. > > If the sender resides on another node, we actually need to reply to > IP and IPv6 packets ourselves and send these ICMP or ICMPv6 errors > back, using the same encapsulating device. Patch 2/6, based on an > original idea by Florian Westphal, adds the needed functionality, > while patches 3/6 and 4/6 add matching support for VXLAN and GENEVE. > > Finally, 5/6 and 6/6 introduce selftests for all combinations of > inner and outer IP versions, covering both VXLAN and GENEVE, with > both regular bridges and Open vSwitch instances. Please address the feedback you've received and I will apply this series, thank you.