From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:36260) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UEyDZ-0001JD-6B for qemu-devel@nongnu.org; Mon, 11 Mar 2013 04:36:26 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UEyDX-0004Co-65 for qemu-devel@nongnu.org; Mon, 11 Mar 2013 04:36:25 -0400 Received: from mail-wg0-x229.google.com ([2a00:1450:400c:c00::229]:64056) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UEyDW-0004Ch-WD for qemu-devel@nongnu.org; Mon, 11 Mar 2013 04:36:23 -0400 Received: by mail-wg0-f41.google.com with SMTP id ds1so1781095wgb.4 for ; Mon, 11 Mar 2013 01:36:22 -0700 (PDT) Date: Mon, 11 Mar 2013 09:36:14 +0100 From: Stefan Hajnoczi Message-ID: <20130311083614.GA28434@stefanha-thinkpad.redhat.com> References: <20130305163510.GC3177@type.bordeaux.inria.fr> <20130306122937.GD1954@stefanha-thinkpad.muc.redhat.com> <20130310200152.GY6036@type.youpi.perso.aquilenet.fr> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20130310200152.GY6036@type.youpi.perso.aquilenet.fr> Subject: Re: [Qemu-devel] [PER] Re: socket, mcast looping back frames -> IPv6 broken List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Samuel Thibault , ped@listes.subiron.org, qemu-devel@nongnu.org On Sun, Mar 10, 2013 at 09:01:52PM +0100, Samuel Thibault wrote: > Stefan Hajnoczi, le Wed 06 Mar 2013 13:29:37 +0100, a écrit : > > > What do people think about it? > > > > We should fix the layer that introduces the problem. Therefore I think > > the fix needs to be net/socket.c. > > > > Unfortunately net/socket.c does not have the concept of a link-layer > > address, so we cannot easily filter out multicast packets coming from > > our NIC's address. > > > > Are you aware of a way to filter out just the packets sent by *this* > > process? > > So in the end I couldn't find any way (even Linuxish) to distinguish > packets coming from self or from other qemus running on the same host, > event with recvmsg etc. > > So, it seems if we want to fix the issue we'll have to filter by source > MAC address. Since the guest can actually change its own MACs, we'd > have to learn them on the fly. We can also implement some aging on the > entries in case the user migrates a MAC from a VM to another. Yes, the guest may use multiple MACs at the same time (e.g. nested virtualization). > Otherwise we may just document that one has to disable Duplicate Address > Detection to get IPv6 working :/ Seems like this might be the only way for now. Stefan