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, URIBL_BLOCKED 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 5C10EC433E0 for ; Tue, 21 Jul 2020 22:55:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3EDDE2073A for ; Tue, 21 Jul 2020 22:55:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728973AbgGUWzq (ORCPT ); Tue, 21 Jul 2020 18:55:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48764 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726148AbgGUWzq (ORCPT ); Tue, 21 Jul 2020 18:55:46 -0400 Received: from shards.monkeyblade.net (shards.monkeyblade.net [IPv6:2620:137:e000::1:9]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0B8B6C061794 for ; Tue, 21 Jul 2020 15:55:46 -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 89EDF11E45904; Tue, 21 Jul 2020 15:39:00 -0700 (PDT) Date: Tue, 21 Jul 2020 15:55:44 -0700 (PDT) Message-Id: <20200721.155544.425274580821501846.davem@davemloft.net> To: geffrey.guo@huawei.com Cc: kuba@kernel.org, maheshb@google.com, edumazet@google.com, netdev@vger.kernel.org Subject: Re: [PATCH] ipvlan: add the check of ip header checksum From: David Miller In-Reply-To: <1595336962-98677-1-git-send-email-geffrey.guo@huawei.com> References: <1595336962-98677-1-git-send-email-geffrey.guo@huawei.com> 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, 21 Jul 2020 15:39:00 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: guodeqing Date: Tue, 21 Jul 2020 21:09:22 +0800 > The ip header checksum can be error in the following steps. ... > $ ip netns exec ns1 tc qdisc add dev ip1 root netem corrupt 50% This is not valid. The kernel internally already validated the ipv4 header checksum before forwarding or sending it on egress to the ipvlan device. The driver can legitimately depend upon this validation. Besides, as Cong pointed out, so much other code in the ipvlan driver has read various ipv4 header members such as the addresses necessary to perform lookups.