From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id; bh=uVk9kx5eAlDza+12N78fhuYNrT6o+5iqmuXfOtuUeqU=; b=f6rwXpOjbO/4+d6C/aVlH+8RkkpbwYb0zd2lory7/X2VBDXpMLIYvLFDc3ZtWGtLPa YaRSZyazu++97bBAqjV9w7oVFT1DZ3GGf6kk7DtvkiYqbXDk/IPIiLAwxShownd/lMb9 Pp8Nvst2j3TwTUqGAE1H/F/ASIWhyzdNhdYP0P4bEqJUruVmCOY2b9VwKxDDNitrNUu0 Z+Wu3pxFqTFc28RzWRBwq4kGrmbpUC+fOhkl5K6/xe0YiKsC31pLKqtBxn3YUUnzmlRY oEsauC9yZO8ugrNOmZPaKLw4ifXgGZD1juOJAAvekZcJrwJ6M4/2LT0/DKDwnMlReMo4 0DEQ== From: Jon Maxwell Date: Fri, 16 May 2014 17:28:44 +1000 Message-Id: <1400225324-17748-1-git-send-email-jmaxwell@redhat.com> Subject: [Bridge] [PATCH net] bridge: notify user space of fdb port change List-Id: Linux Ethernet Bridging List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: stephen@networkplumber.org Cc: vyasevic@redhat.com, jpirko@redhat.com, netdev@vger.kernel.org, jmaxwell@redhat.com, bridge@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Jon Maxwell , davem@davemloft.net 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..c2642f5 100644 --- a/net/bridge/br_fdb.c +++ b/net/bridge/br_fdb.c @@ -509,6 +509,8 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source, /* fastpath: update of existing entry */ fdb->dst = source; fdb->updated = jiffies; + if (unlikely(source->port_no != fdb->dst->port_no)) + fdb_notify(br, fdb, RTM_NEWNEIGH); if (unlikely(added_by_user)) fdb->added_by_user = 1; } -- 1.8.3.1