From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 66D3D46B3 for ; Fri, 6 Oct 2023 06:06:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=none 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> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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=-1.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_BLOCKED,SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Henrik Lindström 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.