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=RJlc+dBYithmwhx3zAa5Uz6DdaMzjDGyXdHwTsAzx9k=; b=T4WhLPMozlWJaSTVxVvuyIjYQoS5d+IV8UsuRmNiwscD9mUjSVHfGAmAXVkAWeh0mO kO3oSpoN44Unw5sa2uNwWanLQFs/ZFK+o2ofcLV1KhV4onYHddb2zh2MJFZv6Ewmz27r 259x64bTV7zyg0wTMIfkWccRbX+8KO+LWDO2lPaEOwUnYTTZsGuxOdpfhu4v2efvuwhf NYBAnfW4QqzjG1A6/v2xgR1ehtyddhTOtZ+XUaRTj0ubIb2cu7VkwUBuRxOqv5TR4f15 tPFuBTg5F+cZyAhfl8Be9ri8biOWDXaSMwlOx2chqJAIONQu7ib2U6kLjf6XsHfTGn2K X1ug== From: Jon Maxwell Date: Thu, 29 May 2014 17:27:16 +1000 Message-Id: <1401348436-5187-1-git-send-email-jmaxwell37@gmail.com> Subject: [Bridge] [PATCH net] bridge: notify user space after fdb update 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, jmaxwell37@gmail.com, davem@davemloft.net 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..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); -- 1.8.3.1