From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vlad Yasevich Subject: Re: [PATCH net] bridge: notify user space after fdb update Date: Wed, 28 May 2014 11:02:27 -0400 Message-ID: <5385FA83.3080301@redhat.com> References: <1401230749-19507-1-git-send-email-jmaxwell37@gmail.com> Reply-To: vyasevic@redhat.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: jpirko@redhat.com, netdev@vger.kernel.org, jmaxwell@redhat.com, bridge@lists.linux-foundation.org, linux-kernel@vger.kernel.org, davem@davemloft.net To: Jon Maxwell , stephen@networkplumber.org Return-path: In-Reply-To: <1401230749-19507-1-git-send-email-jmaxwell37@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: bridge-bounces@lists.linux-foundation.org Errors-To: bridge-bounces@lists.linux-foundation.org List-Id: netdev.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); >