net: dsa: sja1105: enforce FDB isolation

For sja1105, to enforce FDB isolation simply means to turn on
Independent VLAN Learning unconditionally, and to remap VLAN-unaware FDB
and MDB entries towards the private VLAN allocated by tag_8021q for each
bridge.

Standalone ports each have their own standalone tag_8021q VLAN. No
learning happens in that VLAN due to:
- learning being disabled on standalone user ports
- learning being disabled on the CPU port (we use
  assisted_learning_on_cpu_port which only installs bridge FDBs)

VLAN-aware ports learn FDB entries with the bridge VLANs.

VLAN-unaware bridge ports learn with the tag_8021q VLAN for bridging.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/sja1105/sja1105_main.c

@@ -393,10 +393,8 @@ static int sja1105_init_l2_lookup_params(struct sja1105_private *priv)
 		.start_dynspc = 0,
 		/* 2^8 + 2^5 + 2^3 + 2^2 + 2^1 + 1 in Koopman notation */
 		.poly = 0x97,
-		/* This selects between Independent VLAN Learning (IVL) and
-		 * Shared VLAN Learning (SVL)
-		 */
-		.shared_learn = true,
+		/* Always use Independent VLAN Learning (IVL) */
+		.shared_learn = false,
 		/* Don't discard management traffic based on ENFPORT -
 		 * we don't perform SMAC port enforcement anyway, so
 		 * what we are setting here doesn't matter.
@@ -1808,6 +1806,19 @@ static int sja1105_fdb_add(struct dsa_switch *ds, int port,
 {
 	struct sja1105_private *priv = ds->priv;
 
+	if (!vid) {
+		switch (db.type) {
+		case DSA_DB_PORT:
+			vid = dsa_tag_8021q_standalone_vid(db.dp);
+			break;
+		case DSA_DB_BRIDGE:
+			vid = dsa_tag_8021q_bridge_vid(db.bridge.num);
+			break;
+		default:
+			return -EOPNOTSUPP;
+		}
+	}
+
 	return priv->info->fdb_add_cmd(ds, port, addr, vid);
 }
 
@@ -1817,13 +1828,25 @@ static int sja1105_fdb_del(struct dsa_switch *ds, int port,
 {
 	struct sja1105_private *priv = ds->priv;
 
+	if (!vid) {
+		switch (db.type) {
+		case DSA_DB_PORT:
+			vid = dsa_tag_8021q_standalone_vid(db.dp);
+			break;
+		case DSA_DB_BRIDGE:
+			vid = dsa_tag_8021q_bridge_vid(db.bridge.num);
+			break;
+		default:
+			return -EOPNOTSUPP;
+		}
+	}
+
 	return priv->info->fdb_del_cmd(ds, port, addr, vid);
 }
 
 static int sja1105_fdb_dump(struct dsa_switch *ds, int port,
 			    dsa_fdb_dump_cb_t *cb, void *data)
 {
-	struct dsa_port *dp = dsa_to_port(ds, port);
 	struct sja1105_private *priv = ds->priv;
 	struct device *dev = ds->dev;
 	int i;
@@ -1860,7 +1883,7 @@ static int sja1105_fdb_dump(struct dsa_switch *ds, int port,
 		u64_to_ether_addr(l2_lookup.macaddr, macaddr);
 
 		/* We need to hide the dsa_8021q VLANs from the user. */
-		if (!dsa_port_is_vlan_filtering(dp))
+		if (vid_is_dsa_8021q(l2_lookup.vlanid))
 			l2_lookup.vlanid = 0;
 		rc = cb(macaddr, l2_lookup.vlanid, l2_lookup.lockeds, data);
 		if (rc)
@@ -2354,7 +2377,6 @@ sja1105_get_tag_protocol(struct dsa_switch *ds, int port,
 int sja1105_vlan_filtering(struct dsa_switch *ds, int port, bool enabled,
 			   struct netlink_ext_ack *extack)
 {
-	struct sja1105_l2_lookup_params_entry *l2_lookup_params;
 	struct sja1105_general_params_entry *general_params;
 	struct sja1105_private *priv = ds->priv;
 	struct sja1105_table *table;
@@ -2392,28 +2414,6 @@ int sja1105_vlan_filtering(struct dsa_switch *ds, int port, bool enabled,
 	general_params->incl_srcpt1 = enabled;
 	general_params->incl_srcpt0 = enabled;
 
-	/* VLAN filtering => independent VLAN learning.
-	 * No VLAN filtering (or best effort) => shared VLAN learning.
-	 *
-	 * In shared VLAN learning mode, untagged traffic still gets
-	 * pvid-tagged, and the FDB table gets populated with entries
-	 * containing the "real" (pvid or from VLAN tag) VLAN ID.
-	 * However the switch performs a masked L2 lookup in the FDB,
-	 * effectively only looking up a frame's DMAC (and not VID) for the
-	 * forwarding decision.
-	 *
-	 * This is extremely convenient for us, because in modes with
-	 * vlan_filtering=0, dsa_8021q actually installs unique pvid's into
-	 * each front panel port. This is good for identification but breaks
-	 * learning badly - the VID of the learnt FDB entry is unique, aka
-	 * no frames coming from any other port are going to have it. So
-	 * for forwarding purposes, this is as though learning was broken
-	 * (all frames get flooded).
-	 */
-	table = &priv->static_config.tables[BLK_IDX_L2_LOOKUP_PARAMS];
-	l2_lookup_params = table->entries;
-	l2_lookup_params->shared_learn = !enabled;
-
 	for (port = 0; port < ds->num_ports; port++) {
 		if (dsa_is_unused_port(ds, port))
 			continue;
@@ -3099,6 +3099,7 @@ static int sja1105_setup(struct dsa_switch *ds)
 	 */
 	ds->vlan_filtering_is_global = true;
 	ds->untag_bridge_pvid = true;
+	ds->fdb_isolation = true;
 	/* tag_8021q has 3 bits for the VBID, and the value 0 is reserved */
 	ds->max_num_bridges = 7;