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=-0.7 required=3.0 tests=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 3FC95C3A589 for ; Tue, 20 Aug 2019 20:58:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1F26422D6D for ; Tue, 20 Aug 2019 20:58:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730704AbfHTU6E (ORCPT ); Tue, 20 Aug 2019 16:58:04 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:51012 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729833AbfHTU6E (ORCPT ); Tue, 20 Aug 2019 16:58:04 -0400 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::d71]) (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 C2E66148190A1; Tue, 20 Aug 2019 13:58:03 -0700 (PDT) Date: Tue, 20 Aug 2019 13:58:03 -0700 (PDT) Message-Id: <20190820.135803.846099092737191145.davem@davemloft.net> To: liudongxu3@huawei.com Cc: kuznet@ms2.inr.ac.ru, yoshfuji@linux-ipv6.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] net: Fix detection for IPv4 duplicate address. From: David Miller In-Reply-To: <20190820151905.13148-1-liudongxu3@huawei.com> References: <20190820151905.13148-1-liudongxu3@huawei.com> X-Mailer: Mew version 6.8 on Emacs 26.1 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, 20 Aug 2019 13:58:04 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Dongxu Liu Date: Tue, 20 Aug 2019 23:19:05 +0800 > @@ -800,8 +800,11 @@ static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb) > iptunnel_metadata_reply(skb_metadata_dst(skb), > GFP_ATOMIC); > > - /* Special case: IPv4 duplicate address detection packet (RFC2131) */ > - if (sip == 0) { > +/* Special case: IPv4 duplicate address detection packet (RFC2131). > + * Linux usually sends zero to detect duplication, and windows may > + * send a same ip (not zero, sip equal to tip) to do this detection. > + */ > + if (sip == 0 || sip == tip) { Regardless of whether this is a valid change or not, you've unindented the comment which is completely inappropriate.