net: mscc: ocelot: enforce FDB isolation when VLAN-unaware
Currently ocelot uses a pvid of 0 for standalone ports and ports under a VLAN-unaware bridge, and the pvid of the bridge for ports under a VLAN-aware bridge. Standalone ports do not perform learning, but packets received on them are still subject to FDB lookups. So if the MAC DA that a standalone port receives has been also learned on a VLAN-unaware bridge port, ocelot will attempt to forward to that port, even though it can't, so it will drop packets. So there is a desire to avoid that, and isolate the FDBs of different bridges from one another, and from standalone ports. The ocelot switch library has two distinct entry points: the felix DSA driver and the ocelot switchdev driver. We need to code up a minimal bridge_num allocation in the ocelot switchdev driver too, this is copied from DSA with the exception that ocelot does not care about DSA trees, cross-chip bridging etc. So it only looks at its own ports that are already in the same bridge. The ocelot switchdev driver uses the bridge_num it has allocated itself, while the felix driver uses the bridge_num allocated by DSA. They are both stored inside ocelot_port->bridge_num by the common function ocelot_port_bridge_join() which receives the bridge_num passed by value. Once we have a bridge_num, we can only use it to enforce isolation between VLAN-unaware bridges. As far as I can see, ocelot does not have anything like a FID that further makes VLAN 100 from a port be different to VLAN 100 from another port with regard to FDB lookup. So we simply deny multiple VLAN-aware bridges. For VLAN-unaware bridges, we crop the 4000-4095 VLAN region and we allocate a VLAN for each bridge_num. This will be used as the pvid of each port that is under that VLAN-unaware bridge, for as long as that bridge is VLAN-unaware. VID 0 remains only for standalone ports. It is okay if all standalone ports use the same VID 0, since they perform no address learning, the FDB will contain no entry in VLAN 0, so the packets will always be flooded to the only possible destination, the CPU port. The CPU port module doesn't need to be member of the VLANs to receive packets, but if we use the DSA tag_8021q protocol, those packets are part of the data plane as far as ocelot is concerned, so there it needs to. Just ensure that the DSA tag_8021q CPU port is a member of all reserved VLANs when it is created, and is removed when it is deleted. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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