bridge: notify user space after fdb update
authorJon Maxwell <jmaxwell37@gmail.com>
Thu, 29 May 2014 07:27:16 +0000 (17:27 +1000)
committerDavid S. Miller <davem@davemloft.net>
Mon, 2 Jun 2014 05:14:50 +0000 (22:14 -0700)
commitc65c7a306610ee7c13669a8f5601b472c19dc6f1
treef5fef2264059061533b8cdbc10131f807a146486
parent4324be1e0bab67194a263be263b7e48c176d43c7
bridge: notify user space after fdb update

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@gmail.com>
Reviewed-by: Jiri Pirko <jiri@resnulli.us>
Acked-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/bridge/br_fdb.c