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[2620:137:e000::3:3]) by mx.google.com with ESMTPS id s194-20020a6377cb000000b0058988e09e36si1014067pgc.190.2023.10.05.23.06.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Oct 2023 23:06:58 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:3 as permitted sender) client-ip=2620:137:e000::3:3; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:3 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by lipwig.vger.email (Postfix) with ESMTP id 0FE8F80279E7; Thu, 5 Oct 2023 23:06:56 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at lipwig.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230161AbjJFGGq (ORCPT + 99 others); Fri, 6 Oct 2023 02:06:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59870 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230138AbjJFGGp (ORCPT ); Fri, 6 Oct 2023 02:06:45 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:237:300::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8E19690; Thu, 5 Oct 2023 23:06:42 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1qodyp-0006fE-FF; Fri, 06 Oct 2023 08:06:31 +0200 Date: Fri, 6 Oct 2023 08:06:31 +0200 From: Florian Westphal To: Henrik =?iso-8859-15?Q?Lindstr=F6m?= Cc: Florian Westphal , davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: macvtap performs IP defragmentation, causing MTU problems for virtual machines Message-ID: <20231006060631.GC11420@breakpoint.cc> References: <2197902.NgBsaNRSFp@pc> <20231004080037.GC15013@breakpoint.cc> <3259970.44csPzL39Z@pc> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <3259970.44csPzL39Z@pc> User-Agent: Mutt/1.10.1 (2018-07-13) X-Spam-Status: No, score=-0.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lipwig.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (lipwig.vger.email [0.0.0.0]); Thu, 05 Oct 2023 23:06:56 -0700 (PDT) Henrik Lindstr?m wrote: > On onsdag 4 oktober 2023 10:00:37 CEST Florian Westphal wrote: > > Can you submit this formally, with proper changelog and Signed-off-by? > > See scripts/checkpatch.pl in the kernel tree. > Sure, i can give it a shot. How do i properly credit you if i submit your > patch with some small changes of my own? You can use: "Suggested-by:" tag here. > > You could also mention in changelog that this is ipv4 only because > > ipv6 already considers the interface index during reassembly. > Interesting. I've been trying to understand the code and it seems like > ipv6 does defragmentation per-interface, while ipv4 does it "per-vrf" > (correct me if i'm wrong). Is there any reason for this difference? Only for linklocal and multicasts. Added in 264640fc2c5f4f913db5c73fa3eb1ead2c45e9d7 . Even mentions macvlan in the changelog. > The idea being that bcast/mcast packets are always defragmented > per-interface, and unicast packets always "per-vrf". LGTM, but please CC dsahern@kernel.org once you submit the patch.