From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Fri, 30 May 2014 07:32:24 -0700 From: Stephen Hemminger Message-ID: <20140530073224.2d0baa37@nehalam.linuxnetplumber.net> In-Reply-To: <1401348436-5187-1-git-send-email-jmaxwell37@gmail.com> References: <1401348436-5187-1-git-send-email-jmaxwell37@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [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: Jon Maxwell Cc: vyasevic@redhat.com, jpirko@redhat.com, netdev@vger.kernel.org, jmaxwell@redhat.com, bridge@lists.linux-foundation.org, linux-kernel@vger.kernel.org, davem@davemloft.net On Thu, 29 May 2014 17:27:16 +1000 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 Acked-by: Stephen Hemminger