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Date: Wed, 28 May 2014 11:02:27 -0400 From: Vlad Yasevich <vyasevic@...hat.com> To: Jon Maxwell <jmaxwell37@...il.com>, stephen@...workplumber.org CC: davem@...emloft.net, makita.toshiaki@....ntt.co.jp, bridge@...ts.linux-foundation.org, netdev@...r.kernel.org, linux-kernel@...r.kernel.org, jpirko@...hat.com, jmaxwell@...hat.com Subject: Re: [PATCH net] bridge: notify user space after fdb update 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 <jmaxwell37@...il.com> > --- > 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); > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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