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 C59B8C433DF for ; Tue, 4 Aug 2020 20:02:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A5C5620842 for ; Tue, 4 Aug 2020 20:02:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726101AbgHDUCV (ORCPT ); Tue, 4 Aug 2020 16:02:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52146 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725999AbgHDUCV (ORCPT ); Tue, 4 Aug 2020 16:02:21 -0400 Received: from shards.monkeyblade.net (shards.monkeyblade.net [IPv6:2620:137:e000::1:9]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 527E4C06174A for ; Tue, 4 Aug 2020 13:02:21 -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 BCAE612880DE9; Tue, 4 Aug 2020 12:45:34 -0700 (PDT) Date: Tue, 04 Aug 2020 13:02:19 -0700 (PDT) Message-Id: <20200804.130219.1503615086211769091.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 v2 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]); Tue, 04 Aug 2020 12:45:35 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Stefano Brivio Date: Tue, 4 Aug 2020 07:53:41 +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. > > v2: Add helper to check for any bridge port, skip oif check for PMTU > routes for bridge ports only, split IPv4 and IPv6 helpers and > functions (all suggested by David Ahern) Series applied with the extraneous newline in the selftest changes of patch #5 removed. Thank you.