| Message ID | 1401348436-5187-1-git-send-email-jmaxwell37@gmail.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
Thu, May 29, 2014 at 09:27:16AM CEST, jmaxwell37@gmail.com 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@gmail.com> Reviewed-by: Jiri Pirko <jiri@resnulli.us> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
(2014/05/29 16:27), 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@gmail.com> Acked-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, 29 May 2014 17:27:16 +1000 Jon Maxwell <jmaxwell37@gmail.com> 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@gmail.com> Acked-by: Stephen Hemminger <stephen@networkplumber.org> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Jon Maxwell <jmaxwell37@gmail.com> Date: Thu, 29 May 2014 17:27:16 +1000 > 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> Applied, thanks. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c index 9203d5a..474d36f 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 = false; /* 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 = true; + } 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);
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> --- net/bridge/br_fdb.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)