On 01.03.2011 14:29, Daniel Lezcano wrote: > On 02/28/2011 08:45 AM, Eric Dumazet wrote: >>> In the normal case, dummy0 is supposed to drop the packets. But with >>> macvlan these packets are broadcasted to the other macvlan ports, so no >>> checksum is computed when the packets are transmitted between macvlan1 >>> and macvlan2. >> So where frames get bad checksums ? >> >> In this "bridge" mode, I suspect the broadcast is done _before_ sending >> frame to dummy, so maybe macvlan should not inherit from lowerdev in >> this particular case ? > > Hi Eric, > > yes, you are right, the packets are sent before. > > In the 'macvlan_queue_xmit', the code checks the dev is in 'bridge' > mode. If so, it looks if there is a destination port for the packet and > then calls the 'forward' callback which is 'dev_forward_skb'. > > I was able to reproduce the same problem with qemu and an emulated > 'e1000' card instead of dummy0. The packets are dropped too. > > Patrick, do you have any suggestions to fix this ?
Since the frames are only looped back locally, I suppose the easiest fix would be to mark them with CHECKSUM_UNNECESSARY. Alternatively we need to complete the checksum manually, similar to what dev_hard_start_xmit() does. ------------------------------------------------------------------------------ Free Software Download: Index, Search & Analyze Logs and other IT data in Real-Time with Splunk. Collect, index and harness all the fast moving IT data generated by your applications, servers and devices whether physical, virtual or in the cloud. Deliver compliance at lower cost and gain new business insights. http://p.sf.net/sfu/splunk-dev2dev _______________________________________________ Lxc-users mailing list Lxc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/lxc-users
