From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753299AbaEMPQ3 (ORCPT ); Tue, 13 May 2014 11:16:29 -0400 Received: from mail-ee0-f54.google.com ([74.125.83.54]:56565 "EHLO mail-ee0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753109AbaEMPQP (ORCPT ); Tue, 13 May 2014 11:16:15 -0400 Date: Tue, 13 May 2014 17:16:11 +0200 From: Jiri Pirko To: Jon Maxwell Cc: stephen@networkplumber.org, davem@davemloft.net, 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 of fdb port change Message-ID: <20140513151611.GA2966@minipsycho.orion> References: <1399967708-7283-1-git-send-email-jmaxwell@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1399967708-7283-1-git-send-email-jmaxwell@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Tue, May 13, 2014 at 09:55:08AM CEST, jmaxwell37@gmail.com wrote: >From: Jon Maxwell > >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 to identify such port toggling. > >Signed-off-by: Jon Maxwell >--- > net/bridge/br_fdb.c | 2 ++ > 1 file changed, 2 insertions(+) > >diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c >index 9203d5a..37742e2 100644 >--- a/net/bridge/br_fdb.c >+++ b/net/bridge/br_fdb.c >@@ -507,6 +507,8 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source, > source->dev->name); > } else { > /* fastpath: update of existing entry */ >+ if (source->port_no != fdb->dst->port_no) >+ fdb_notify(br, fdb, RTM_NEWNEIGH); > fdb->dst = source; > fdb->updated = jiffies; > if (unlikely(added_by_user)) >-- >1.8.3.1 Reviewed-by: Jiri Pirko