Re: [patch net-next] mlxsw: spectrum_switchdev: Allow port enslavement to a VLAN-unaware bridge

On 2/21/18 1:24 PM, Ido Schimmel wrote:

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Does it matter if you try IPv4 ping or if vlan_filtering is set 1?
Unfortunately, I can't reproduce on my switch.

Bring up the hosts and then reboot the switch. At that point I get no
host to host communication. As soon as I flap the port on host1 host3 to
host1 starts working.

So it seems to be something about the initial boot state.

You didn't have IPv6 *and* IPv4 ping? I'm asking because it's possible
host1 sent an MLD join to the Solicited-node multicast address before
the bridge started listening, which means it didn't have a corresponding
MDB entry.

The sim only configures IPv6, but it is not acting as an mcast router.
It's really a dummy setup -- bridge on the switch, ports connected to hosts.

Assuming your hosts aren't functioning as multicast routers and sending
MLD queries and that you didn't configure them as mrouter ports on the
switch, then when host3 sent a neighbour solicitation message to host1's
Solicited-node multicast address it wasn't flooded to host3 which
prevented ping from passing.

This also explains why it started working when you flapped the port on
host1, as Linux generates MLD joins in these cases.

You can try to disable snooping:

# ip link set dev br0 type bridge mcast_snooping 0

Just a guess, but worth a try.

good guess. That change gets it working.