From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752277AbaFBFPU (ORCPT ); Mon, 2 Jun 2014 01:15:20 -0400 Received: from shards.monkeyblade.net ([149.20.54.216]:56314 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751673AbaFBFPR (ORCPT ); Mon, 2 Jun 2014 01:15:17 -0400 Date: Sun, 01 Jun 2014 22:15:15 -0700 (PDT) Message-Id: <20140601.221515.360490928652338768.davem@davemloft.net> To: jmaxwell37@gmail.com Cc: stephen@networkplumber.org, makita.toshiaki@lab.ntt.co.jp, vyasevic@redhat.com, bridge@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, jpirko@redhat.com, jmaxwell@redhat.com Subject: Re: [PATCH net] bridge: notify user space after fdb update From: David Miller In-Reply-To: <1401348436-5187-1-git-send-email-jmaxwell37@gmail.com> References: <1401348436-5187-1-git-send-email-jmaxwell37@gmail.com> X-Mailer: Mew version 6.5 on Emacs 24.1 / Mule 6.0 (HANACHIRUSATO) 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-4.5.7 (shards.monkeyblade.net [149.20.54.216]); Sun, 01 Jun 2014 22:15:16 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jon Maxwell Date: Thu, 29 May 2014 17:27:16 +1000 > There has been a number incidents recently where customers running KVM have > reported that VM hosts on different Hypervisors are unreachable. Based on > pcap traces we found that the bridge was broadcasting the ARP request out > onto the network. However some NICs have an inbuilt switch which on occasions > were broadcasting the VMs ARP request back through the physical NIC on the > Hypervisor. This resulted in the bridge changing ports and incorrectly learning > that the VMs mac address was external. As a result the ARP reply was directed > back onto the external network and VM never updated it's ARP cache. This patch > will notify the bridge command, after a fdb has been updated to identify such > port toggling. > > Signed-off-by: Jon Maxwell Applied, thanks.