On Tue, Mar 04, 2014 at 06:06:29AM -0500, Jan Stancek wrote: > > > ----- Original Message ----- > > From: "Linus Lüssing" <linus.luessing@xxxxxx> > > To: "Jan Stancek" <jstancek@xxxxxxxxxx> > > Cc: netdev@xxxxxxxxxxxxxxx, "Florian Westphal" <fwestpha@xxxxxxxxxx>, bridge@xxxxxxxxxxxxxxxxxxxxxxxxxx > > Sent: Tuesday, 4 March, 2014 11:52:54 AM > > Subject: Re: bridge is not forwaring ICMP6 neighbor solicitation to KVM guest > > > > Hi Jan, > > > > On Tue, Mar 04, 2014 at 03:02:36AM -0500, Jan Stancek wrote: > > > > For the broken query, ok, it's your manually crafted query. But > > > > did you see a query with such a bogus source address "in the > > > > wild", too? (I'm curious how urgent this sanity check is) > > > > > > It's real packet I managed to capture during one such occurrence. > > > I'm sending it with small C program over raw socket, but it's byte > > > by byte exact copy of what I captured with tcpdump previously. > > > > > > I'm not sure how that packet came to existence. Based on IPv6 address > > > it came from host B, but all host B was doing at the time > > > was running RHEL6 with couple qemu-kvm instances. KVM guests were > > > set up to use bridge, so I'm assuming if any of them crafted > > > this packet, source IPv6 address would be different. > > > > > > > Ah, okay. Can you check whether it maybe came from the querier > > code in the Linux bridge on host B? Is > > "cat /sys/class/net/br0/bridge/multicast_querier" 1? > > # cat /sys/class/net/br0/bridge/multicast_querier > cat: /sys/class/net/br0/bridge/multicast_querier: No such file or directory Ok, that's not present on such old kernels, there it is actually enabled by default. > > > Can you isolate host B and disable any multicast router daemon on it? Then > > check again, if you still see these queries. > > Besides those cases where I sent it by myself, I haven't seen host B send > that query for couple days now. > > > What kernel version is running on host B? > > 2.6.32-279.42.1.el6.x86_64 > It's a RHEL6.3.z kernel. > > > Where does Linux use :: for queries? > > I'm not sure if it's Linux (I'm trying to locate that system by MAC), but I see > packets like these on my network every ~125 seconds: > > No. Time Source Destination Protocol Length Info > 22675 1334.751135 :: ff02::1 ICMPv6 86 Multicast Listener Query It's probably the bridge on this ancient kernel, you might want to backport the following patch: "bridge: Use IPv6 link-local address for multicast listener queries" (fe29ec41aaa51902aebd63658dfb04fe6fea8be5) And it's follow-up fixes: "bridge: Fix possibly wrong MLD queries' ethernet source address" (a7bff75b087e7a355838a32efe61707cfa73c194) "bridge: check return value of ipv6_dev_get_saddr()" (d1d81d4c3dd886d5fa25a2c4fa1e39cb89613712) If these patches on host B xor the sanity check I just submitted applied on your host A / VM host fix your issue, then they might be worth considering for the stable queue. Cheers, Linus
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