From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932070AbaE1PCo (ORCPT ); Wed, 28 May 2014 11:02:44 -0400 Received: from mx1.redhat.com ([209.132.183.28]:61598 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752901AbaE1PCm (ORCPT ); Wed, 28 May 2014 11:02:42 -0400 Message-ID: <5385FA83.3080301@redhat.com> Date: Wed, 28 May 2014 11:02:27 -0400 From: Vlad Yasevich Reply-To: vyasevic@redhat.com Organization: Red Hat User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: Jon Maxwell , stephen@networkplumber.org CC: davem@davemloft.net, makita.toshiaki@lab.ntt.co.jp, 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 References: <1401230749-19507-1-git-send-email-jmaxwell37@gmail.com> In-Reply-To: <1401230749-19507-1-git-send-email-jmaxwell37@gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/27/2014 06:45 PM, Jon Maxwell wrote: > 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 > --- > net/bridge/br_fdb.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c > index 9203d5a..f3ee2da 100644 > --- a/net/bridge/br_fdb.c > +++ b/net/bridge/br_fdb.c > @@ -487,6 +487,7 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source, > { > struct hlist_head *head = &br->hash[br_mac_hash(addr, vid)]; > struct net_bridge_fdb_entry *fdb; > + bool fdb_modified = 0; > > /* some users want to always flood. */ > if (hold_time(br) == 0) > @@ -507,10 +508,15 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source, > source->dev->name); > } else { > /* fastpath: update of existing entry */ > - fdb->dst = source; > + if (unlikely(source != fdb->dst)) { > + fdb->dst = source; > + fdb_modified = 1; > + } This looks over-indented. -vlad > fdb->updated = jiffies; > if (unlikely(added_by_user)) > fdb->added_by_user = 1; > + if (unlikely(fdb_modified)) > + fdb_notify(br, fdb, RTM_NEWNEIGH); > } > } else { > spin_lock(&br->hash_lock); >