From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Maxwell Subject: Re: [PATCH net] bridge: notify user space of fdb port change Date: Fri, 16 May 2014 04:12:51 -0400 (EDT) Message-ID: <255115023.7295678.1400227971937.JavaMail.zimbra@redhat.com> References: <1400227719-18403-1-git-send-email-jmaxwell@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: davem@davemloft.net, makita toshiaki , vyasevic@redhat.com, bridge@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, jpirko@redhat.com To: stephen@networkplumber.org Return-path: In-Reply-To: <1400227719-18403-1-git-send-email-jmaxwell@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Please use this patch. My bad, the previous one incorrectly did the notify before fdb->added_by_user = 1. ----- Original Message ----- > From: "Jon Maxwell" > To: stephen@networkplumber.org > Cc: davem@davemloft.net, "makita toshiaki" , vyasevic@redhat.com, > bridge@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, jpirko@redhat.com, > jmaxwell@redhat.com, "Jon Maxwell" > Sent: Friday, May 16, 2014 6:08:39 PM > Subject: [PATCH net] bridge: notify user space of fdb port change > > 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..67480c2 100644 > --- a/net/bridge/br_fdb.c > +++ b/net/bridge/br_fdb.c > @@ -511,6 +511,8 @@ void br_fdb_update(struct net_bridge *br, struct > net_bridge_port *source, > fdb->updated = jiffies; > if (unlikely(added_by_user)) > fdb->added_by_user = 1; > + if (unlikely(source->port_no != fdb->dst->port_no)) > + fdb_notify(br, fdb, RTM_NEWNEIGH); > } > } else { > spin_lock(&br->hash_lock); > -- > 1.8.3.1 > >