Re: [PATCH v8 net-next 10/12] net: dsa: mv88e6xxx: mac-auth/MAB implementation

[Vladimir Oltean <olteanv@gmail.com>]

On Fri, Oct 21, 2022 at 03:16:21PM +0200, netdev@kapio-technology.com wrote:
> As it is now in the bridge, the locked port part is handled before learning
> in the ingress data path, so with BR_LEARNING and BR_PORT_LOCKED, I think it
> will work as it does now except link local packages.

If link-local learning is enabled on a locked port, I think those
addresses should also be learned with the BR_FDB_LOCKED flag. The
creation of those locked FDB entries can be further suppressed by the
BROPT_NO_LL_LEARN flag.

> If your suggestion of BR_LEARNING causing BR_FDB_LOCKED on a locked port, I
> guess it would be implemented under br_fdb_update() and BR_LEARNING +
> BR_PORT_LOCKED would go together, forcing BR_LEARNING in this case, thus also
> for all drivers?

Yes, basically where this is placed right now (in br_handle_frame_finish):

	if (p->flags & BR_PORT_LOCKED) {
		struct net_bridge_fdb_entry *fdb_src =
			br_fdb_find_rcu(br, eth_hdr(skb)->h_source, vid);

		if (!fdb_src) {
			unsigned long flags = 0;

			if (p->flags & BR_PORT_MAB) {
			   ~~~~~~~~~~~~~~~~~~~~~~~~
			   except check for BR_LEARNING

				__set_bit(BR_FDB_LOCKED, &flags);
				br_fdb_update(br, p, eth_hdr(skb)->h_source,
					      vid, flags);
			}
			goto drop;
		} else if (READ_ONCE(fdb_src->dst) != p ||
			   test_bit(BR_FDB_LOCAL, &fdb_src->flags) ||
			   test_bit(BR_FDB_LOCKED, &fdb_src->flags)) {
			goto drop;
		}
	}