net: dsa: request drivers to perform FDB isolation

For DSA, to encourage drivers to perform FDB isolation simply means to
track which bridge does each FDB and MDB entry belong to. It then
becomes the driver responsibility to use something that makes the FDB
entry from one bridge not match the FDB lookup of ports from other
bridges.

The top-level functions where the bridge is determined are:
- dsa_port_fdb_{add,del}
- dsa_port_host_fdb_{add,del}
- dsa_port_mdb_{add,del}
- dsa_port_host_mdb_{add,del}

aka the pre-crosschip-notifier functions.

Changing the API to pass a reference to a bridge is not superfluous, and
looking at the passed bridge argument is not the same as having the
driver look at dsa_to_port(ds, port)->bridge from the ->port_fdb_add()
method.

DSA installs FDB and MDB entries on shared (CPU and DSA) ports as well,
and those do not have any dp->bridge information to retrieve, because
they are not in any bridge - they are merely the pipes that serve the
user ports that are in one or multiple bridges.

The struct dsa_bridge associated with each FDB/MDB entry is encapsulated
in a larger "struct dsa_db" database. Although only databases associated
to bridges are notified for now, this API will be the starting point for
implementing IFF_UNICAST_FLT in DSA. There, the idea is to install FDB
entries on the CPU port which belong to the corresponding user port's
port database. These are supposed to match only when the port is
standalone.

It is better to introduce the API in its expected final form than to
introduce it for bridges first, then to have to change drivers which may
have made one or more assumptions.

Drivers can use the provided bridge.num, but they can also use a
different numbering scheme that is more convenient.

DSA must perform refcounting on the CPU and DSA ports by also taking
into account the bridge number. So if two bridges request the same local
address, DSA must notify the driver twice, once for each bridge.

In fact, if the driver supports FDB isolation, DSA must perform
refcounting per bridge, but if the driver doesn't, DSA must refcount
host addresses across all bridges, otherwise it would be telling the
driver to delete an FDB entry for a bridge and the driver would delete
it for all bridges. So introduce a bool fdb_isolation in drivers which
would make all bridge databases passed to the cross-chip notifier have
the same number (0). This makes dsa_mac_addr_find() -> dsa_db_equal()
say that all bridge databases are the same database - which is
essentially the legacy behavior.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 141 insertions, 36 deletions

diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index 7a1c98581f53..27575fc3883e 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -67,6 +67,7 @@ struct dsa_notifier_fdb_info {
 	int port;
 	const unsigned char *addr;
 	u16 vid;
+	struct dsa_db db;
 };
 
 /* DSA_NOTIFIER_LAG_FDB_* */
@@ -74,6 +75,7 @@ struct dsa_notifier_lag_fdb_info {
 	struct dsa_lag *lag;
 	const unsigned char *addr;
 	u16 vid;
+	struct dsa_db db;
 };
 
 /* DSA_NOTIFIER_MDB_* */
@@ -81,6 +83,7 @@ struct dsa_notifier_mdb_info {
 	const struct switchdev_obj_port_mdb *mdb;
 	int sw_index;
 	int port;
+	struct dsa_db db;
 };
 
 /* DSA_NOTIFIER_LAG_* */
diff --git a/net/dsa/port.c b/net/dsa/port.c
index adab159c8c21..7af44a28f032 100644
--- a/net/dsa/port.c
+++ b/net/dsa/port.c
@@ -798,8 +798,19 @@ int dsa_port_fdb_add(struct dsa_port *dp, const unsigned char *addr,
 		.port = dp->index,
 		.addr = addr,
 		.vid = vid,
+		.db = {
+			.type = DSA_DB_BRIDGE,
+			.bridge = *dp->bridge,
+		},
 	};
 
+	/* Refcounting takes bridge.num as a key, and should be global for all
+	 * bridges in the absence of FDB isolation, and per bridge otherwise.
+	 * Force the bridge.num to zero here in the absence of FDB isolation.
+	 */
+	if (!dp->ds->fdb_isolation)
+		info.db.bridge.num = 0;
+
 	return dsa_port_notify(dp, DSA_NOTIFIER_FDB_ADD, &info);
 }
 
@@ -811,9 +822,15 @@ int dsa_port_fdb_del(struct dsa_port *dp, const unsigned char *addr,
 		.port = dp->index,
 		.addr = addr,
 		.vid = vid,
-
+		.db = {
+			.type = DSA_DB_BRIDGE,
+			.bridge = *dp->bridge,
+		},
 	};
 
+	if (!dp->ds->fdb_isolation)
+		info.db.bridge.num = 0;
+
 	return dsa_port_notify(dp, DSA_NOTIFIER_FDB_DEL, &info);
 }
 
@@ -825,6 +842,10 @@ int dsa_port_host_fdb_add(struct dsa_port *dp, const unsigned char *addr,
 		.port = dp->index,
 		.addr = addr,
 		.vid = vid,
+		.db = {
+			.type = DSA_DB_BRIDGE,
+			.bridge = *dp->bridge,
+		},
 	};
 	struct dsa_port *cpu_dp = dp->cpu_dp;
 	int err;
@@ -839,6 +860,9 @@ int dsa_port_host_fdb_add(struct dsa_port *dp, const unsigned char *addr,
 			return err;
 	}
 
+	if (!dp->ds->fdb_isolation)
+		info.db.bridge.num = 0;
+
 	return dsa_port_notify(dp, DSA_NOTIFIER_HOST_FDB_ADD, &info);
 }
 
@@ -850,6 +874,10 @@ int dsa_port_host_fdb_del(struct dsa_port *dp, const unsigned char *addr,
 		.port = dp->index,
 		.addr = addr,
 		.vid = vid,
+		.db = {
+			.type = DSA_DB_BRIDGE,
+			.bridge = *dp->bridge,
+		},
 	};
 	struct dsa_port *cpu_dp = dp->cpu_dp;
 	int err;
@@ -860,6 +888,9 @@ int dsa_port_host_fdb_del(struct dsa_port *dp, const unsigned char *addr,
 			return err;
 	}
 
+	if (!dp->ds->fdb_isolation)
+		info.db.bridge.num = 0;
+
 	return dsa_port_notify(dp, DSA_NOTIFIER_HOST_FDB_DEL, &info);
 }
 
@@ -870,8 +901,15 @@ int dsa_port_lag_fdb_add(struct dsa_port *dp, const unsigned char *addr,
 		.lag = dp->lag,
 		.addr = addr,
 		.vid = vid,
+		.db = {
+			.type = DSA_DB_BRIDGE,
+			.bridge = *dp->bridge,
+		},
 	};
 
+	if (!dp->ds->fdb_isolation)
+		info.db.bridge.num = 0;
+
 	return dsa_port_notify(dp, DSA_NOTIFIER_LAG_FDB_ADD, &info);
 }
 
@@ -882,8 +920,15 @@ int dsa_port_lag_fdb_del(struct dsa_port *dp, const unsigned char *addr,
 		.lag = dp->lag,
 		.addr = addr,
 		.vid = vid,
+		.db = {
+			.type = DSA_DB_BRIDGE,
+			.bridge = *dp->bridge,
+		},
 	};
 
+	if (!dp->ds->fdb_isolation)
+		info.db.bridge.num = 0;
+
 	return dsa_port_notify(dp, DSA_NOTIFIER_LAG_FDB_DEL, &info);
 }
 
@@ -905,8 +950,15 @@ int dsa_port_mdb_add(const struct dsa_port *dp,
 		.sw_index = dp->ds->index,
 		.port = dp->index,
 		.mdb = mdb,
+		.db = {
+			.type = DSA_DB_BRIDGE,
+			.bridge = *dp->bridge,
+		},
 	};
 
+	if (!dp->ds->fdb_isolation)
+		info.db.bridge.num = 0;
+
 	return dsa_port_notify(dp, DSA_NOTIFIER_MDB_ADD, &info);
 }
 
@@ -917,8 +969,15 @@ int dsa_port_mdb_del(const struct dsa_port *dp,
 		.sw_index = dp->ds->index,
 		.port = dp->index,
 		.mdb = mdb,
+		.db = {
+			.type = DSA_DB_BRIDGE,
+			.bridge = *dp->bridge,
+		},
 	};
 
+	if (!dp->ds->fdb_isolation)
+		info.db.bridge.num = 0;
+
 	return dsa_port_notify(dp, DSA_NOTIFIER_MDB_DEL, &info);
 }
 
@@ -929,6 +988,10 @@ int dsa_port_host_mdb_add(const struct dsa_port *dp,
 		.sw_index = dp->ds->index,
 		.port = dp->index,
 		.mdb = mdb,
+		.db = {
+			.type = DSA_DB_BRIDGE,
+			.bridge = *dp->bridge,
+		},
 	};
 	struct dsa_port *cpu_dp = dp->cpu_dp;
 	int err;
@@ -937,6 +1000,9 @@ int dsa_port_host_mdb_add(const struct dsa_port *dp,
 	if (err)
 		return err;
 
+	if (!dp->ds->fdb_isolation)
+		info.db.bridge.num = 0;
+
 	return dsa_port_notify(dp, DSA_NOTIFIER_HOST_MDB_ADD, &info);
 }
 
@@ -947,6 +1013,10 @@ int dsa_port_host_mdb_del(const struct dsa_port *dp,
 		.sw_index = dp->ds->index,
 		.port = dp->index,
 		.mdb = mdb,
+		.db = {
+			.type = DSA_DB_BRIDGE,
+			.bridge = *dp->bridge,
+		},
 	};
 	struct dsa_port *cpu_dp = dp->cpu_dp;
 	int err;
@@ -955,6 +1025,9 @@ int dsa_port_host_mdb_del(const struct dsa_port *dp,
 	if (err)
 		return err;
 
+	if (!dp->ds->fdb_isolation)
+		info.db.bridge.num = 0;
+
 	return dsa_port_notify(dp, DSA_NOTIFIER_HOST_MDB_DEL, &info);
 }
 
diff --git a/net/dsa/switch.c b/net/dsa/switch.c
index eb38beb10147..1d3c161e3131 100644
--- a/net/dsa/switch.c
+++ b/net/dsa/switch.c
@@ -210,21 +210,41 @@ static bool dsa_port_host_address_match(struct dsa_port *dp,
 	return false;
 }
 
+static bool dsa_db_equal(const struct dsa_db *a, const struct dsa_db *b)
+{
+	if (a->type != b->type)
+		return false;
+
+	switch (a->type) {
+	case DSA_DB_PORT:
+		return a->dp == b->dp;
+	case DSA_DB_LAG:
+		return a->lag.dev == b->lag.dev;
+	case DSA_DB_BRIDGE:
+		return a->bridge.num == b->bridge.num;
+	default:
+		WARN_ON(1);
+		return false;
+	}
+}
+
 static struct dsa_mac_addr *dsa_mac_addr_find(struct list_head *addr_list,
-					      const unsigned char *addr,
-					      u16 vid)
+					      const unsigned char *addr, u16 vid,
+					      struct dsa_db db)
 {
 	struct dsa_mac_addr *a;
 
 	list_for_each_entry(a, addr_list, list)
-		if (ether_addr_equal(a->addr, addr) && a->vid == vid)
+		if (ether_addr_equal(a->addr, addr) && a->vid == vid &&
+		    dsa_db_equal(&a->db, &db))
 			return a;
 
 	return NULL;
 }
 
 static int dsa_port_do_mdb_add(struct dsa_port *dp,
-			       const struct switchdev_obj_port_mdb *mdb)
+			       const struct switchdev_obj_port_mdb *mdb,
+			       struct dsa_db db)
 {
 	struct dsa_switch *ds = dp->ds;
 	struct dsa_mac_addr *a;
@@ -233,11 +253,11 @@ static int dsa_port_do_mdb_add(struct dsa_port *dp,
 
 	/* No need to bother with refcounting for user ports */
 	if (!(dsa_port_is_cpu(dp) || dsa_port_is_dsa(dp)))
-		return ds->ops->port_mdb_add(ds, port, mdb);
+		return ds->ops->port_mdb_add(ds, port, mdb, db);
 
 	mutex_lock(&dp->addr_lists_lock);
 
-	a = dsa_mac_addr_find(&dp->mdbs, mdb->addr, mdb->vid);
+	a = dsa_mac_addr_find(&dp->mdbs, mdb->addr, mdb->vid, db);
 	if (a) {
 		refcount_inc(&a->refcount);
 		goto out;
@@ -249,7 +269,7 @@ static int dsa_port_do_mdb_add(struct dsa_port *dp,
 		goto out;
 	}
 
-	err = ds->ops->port_mdb_add(ds, port, mdb);
+	err = ds->ops->port_mdb_add(ds, port, mdb, db);
 	if (err) {
 		kfree(a);
 		goto out;
@@ -257,6 +277,7 @@ static int dsa_port_do_mdb_add(struct dsa_port *dp,
 
 	ether_addr_copy(a->addr, mdb->addr);
 	a->vid = mdb->vid;
+	a->db = db;
 	refcount_set(&a->refcount, 1);
 	list_add_tail(&a->list, &dp->mdbs);
 
@@ -267,7 +288,8 @@ out:
 }
 
 static int dsa_port_do_mdb_del(struct dsa_port *dp,
-			       const struct switchdev_obj_port_mdb *mdb)
+			       const struct switchdev_obj_port_mdb *mdb,
+			       struct dsa_db db)
 {
 	struct dsa_switch *ds = dp->ds;
 	struct dsa_mac_addr *a;
@@ -276,11 +298,11 @@ static int dsa_port_do_mdb_del(struct dsa_port *dp,
 
 	/* No need to bother with refcounting for user ports */
 	if (!(dsa_port_is_cpu(dp) || dsa_port_is_dsa(dp)))
-		return ds->ops->port_mdb_del(ds, port, mdb);
+		return ds->ops->port_mdb_del(ds, port, mdb, db);
 
 	mutex_lock(&dp->addr_lists_lock);
 
-	a = dsa_mac_addr_find(&dp->mdbs, mdb->addr, mdb->vid);
+	a = dsa_mac_addr_find(&dp->mdbs, mdb->addr, mdb->vid, db);
 	if (!a) {
 		err = -ENOENT;
 		goto out;
@@ -289,7 +311,7 @@ static int dsa_port_do_mdb_del(struct dsa_port *dp,
 	if (!refcount_dec_and_test(&a->refcount))
 		goto out;
 
-	err = ds->ops->port_mdb_del(ds, port, mdb);
+	err = ds->ops->port_mdb_del(ds, port, mdb, db);
 	if (err) {
 		refcount_set(&a->refcount, 1);
 		goto out;
@@ -305,7 +327,7 @@ out:
 }
 
 static int dsa_port_do_fdb_add(struct dsa_port *dp, const unsigned char *addr,
-			       u16 vid)
+			       u16 vid, struct dsa_db db)
 {
 	struct dsa_switch *ds = dp->ds;
 	struct dsa_mac_addr *a;
@@ -314,11 +336,11 @@ static int dsa_port_do_fdb_add(struct dsa_port *dp, const unsigned char *addr,
 
 	/* No need to bother with refcounting for user ports */
 	if (!(dsa_port_is_cpu(dp) || dsa_port_is_dsa(dp)))
-		return ds->ops->port_fdb_add(ds, port, addr, vid);
+		return ds->ops->port_fdb_add(ds, port, addr, vid, db);
 
 	mutex_lock(&dp->addr_lists_lock);
 
-	a = dsa_mac_addr_find(&dp->fdbs, addr, vid);
+	a = dsa_mac_addr_find(&dp->fdbs, addr, vid, db);
 	if (a) {
 		refcount_inc(&a->refcount);
 		goto out;
@@ -330,7 +352,7 @@ static int dsa_port_do_fdb_add(struct dsa_port *dp, const unsigned char *addr,
 		goto out;
 	}
 
-	err = ds->ops->port_fdb_add(ds, port, addr, vid);
+	err = ds->ops->port_fdb_add(ds, port, addr, vid, db);
 	if (err) {
 		kfree(a);
 		goto out;
@@ -338,6 +360,7 @@ static int dsa_port_do_fdb_add(struct dsa_port *dp, const unsigned char *addr,
 
 	ether_addr_copy(a->addr, addr);
 	a->vid = vid;
+	a->db = db;
 	refcount_set(&a->refcount, 1);
 	list_add_tail(&a->list, &dp->fdbs);
 
@@ -348,7 +371,7 @@ out:
 }
 
 static int dsa_port_do_fdb_del(struct dsa_port *dp, const unsigned char *addr,
-			       u16 vid)
+			       u16 vid, struct dsa_db db)
 {
 	struct dsa_switch *ds = dp->ds;
 	struct dsa_mac_addr *a;
@@ -357,11 +380,11 @@ static int dsa_port_do_fdb_del(struct dsa_port *dp, const unsigned char *addr,
 
 	/* No need to bother with refcounting for user ports */
 	if (!(dsa_port_is_cpu(dp) || dsa_port_is_dsa(dp)))
-		return ds->ops->port_fdb_del(ds, port, addr, vid);
+		return ds->ops->port_fdb_del(ds, port, addr, vid, db);
 
 	mutex_lock(&dp->addr_lists_lock);
 
-	a = dsa_mac_addr_find(&dp->fdbs, addr, vid);
+	a = dsa_mac_addr_find(&dp->fdbs, addr, vid, db);
 	if (!a) {
 		err = -ENOENT;
 		goto out;
@@ -370,7 +393,7 @@ static int dsa_port_do_fdb_del(struct dsa_port *dp, const unsigned char *addr,
 	if (!refcount_dec_and_test(&a->refcount))
 		goto out;
 
-	err = ds->ops->port_fdb_del(ds, port, addr, vid);
+	err = ds->ops->port_fdb_del(ds, port, addr, vid, db);
 	if (err) {
 		refcount_set(&a->refcount, 1);
 		goto out;
@@ -386,14 +409,15 @@ out:
 }
 
 static int dsa_switch_do_lag_fdb_add(struct dsa_switch *ds, struct dsa_lag *lag,
-				     const unsigned char *addr, u16 vid)
+				     const unsigned char *addr, u16 vid,
+				     struct dsa_db db)
 {
 	struct dsa_mac_addr *a;
 	int err = 0;
 
 	mutex_lock(&lag->fdb_lock);
 
-	a = dsa_mac_addr_find(&lag->fdbs, addr, vid);
+	a = dsa_mac_addr_find(&lag->fdbs, addr, vid, db);
 	if (a) {
 		refcount_inc(&a->refcount);
 		goto out;
@@ -405,7 +429,7 @@ static int dsa_switch_do_lag_fdb_add(struct dsa_switch *ds, struct dsa_lag *lag,
 		goto out;
 	}
 
-	err = ds->ops->lag_fdb_add(ds, *lag, addr, vid);
+	err = ds->ops->lag_fdb_add(ds, *lag, addr, vid, db);
 	if (err) {
 		kfree(a);
 		goto out;
@@ -423,14 +447,15 @@ out:
 }
 
 static int dsa_switch_do_lag_fdb_del(struct dsa_switch *ds, struct dsa_lag *lag,
-				     const unsigned char *addr, u16 vid)
+				     const unsigned char *addr, u16 vid,
+				     struct dsa_db db)
 {
 	struct dsa_mac_addr *a;
 	int err = 0;
 
 	mutex_lock(&lag->fdb_lock);
 
-	a = dsa_mac_addr_find(&lag->fdbs, addr, vid);
+	a = dsa_mac_addr_find(&lag->fdbs, addr, vid, db);
 	if (!a) {
 		err = -ENOENT;
 		goto out;
@@ -439,7 +464,7 @@ static int dsa_switch_do_lag_fdb_del(struct dsa_switch *ds, struct dsa_lag *lag,
 	if (!refcount_dec_and_test(&a->refcount))
 		goto out;
 
-	err = ds->ops->lag_fdb_del(ds, *lag, addr, vid);
+	err = ds->ops->lag_fdb_del(ds, *lag, addr, vid, db);
 	if (err) {
 		refcount_set(&a->refcount, 1);
 		goto out;
@@ -466,7 +491,8 @@ static int dsa_switch_host_fdb_add(struct dsa_switch *ds,
 	dsa_switch_for_each_port(dp, ds) {
 		if (dsa_port_host_address_match(dp, info->sw_index,
 						info->port)) {
-			err = dsa_port_do_fdb_add(dp, info->addr, info->vid);
+			err = dsa_port_do_fdb_add(dp, info->addr, info->vid,
+						  info->db);
 			if (err)
 				break;
 		}
@@ -487,7 +513,8 @@ static int dsa_switch_host_fdb_del(struct dsa_switch *ds,
 	dsa_switch_for_each_port(dp, ds) {
 		if (dsa_port_host_address_match(dp, info->sw_index,
 						info->port)) {
-			err = dsa_port_do_fdb_del(dp, info->addr, info->vid);
+			err = dsa_port_do_fdb_del(dp, info->addr, info->vid,
+						  info->db);
 			if (err)
 				break;
 		}
@@ -505,7 +532,7 @@ static int dsa_switch_fdb_add(struct dsa_switch *ds,
 	if (!ds->ops->port_fdb_add)
 		return -EOPNOTSUPP;
 
-	return dsa_port_do_fdb_add(dp, info->addr, info->vid);
+	return dsa_port_do_fdb_add(dp, info->addr, info->vid, info->db);
 }
 
 static int dsa_switch_fdb_del(struct dsa_switch *ds,
@@ -517,7 +544,7 @@ static int dsa_switch_fdb_del(struct dsa_switch *ds,
 	if (!ds->ops->port_fdb_del)
 		return -EOPNOTSUPP;
 
-	return dsa_port_do_fdb_del(dp, info->addr, info->vid);
+	return dsa_port_do_fdb_del(dp, info->addr, info->vid, info->db);
 }
 
 static int dsa_switch_lag_fdb_add(struct dsa_switch *ds,
@@ -532,7 +559,8 @@ static int dsa_switch_lag_fdb_add(struct dsa_switch *ds,
 	dsa_switch_for_each_port(dp, ds)
 		if (dsa_port_offloads_lag(dp, info->lag))
 			return dsa_switch_do_lag_fdb_add(ds, info->lag,
-							 info->addr, info->vid);
+							 info->addr, info->vid,
+							 info->db);
 
 	return 0;
 }
@@ -549,7 +577,8 @@ static int dsa_switch_lag_fdb_del(struct dsa_switch *ds,
 	dsa_switch_for_each_port(dp, ds)
 		if (dsa_port_offloads_lag(dp, info->lag))
 			return dsa_switch_do_lag_fdb_del(ds, info->lag,
-							 info->addr, info->vid);
+							 info->addr, info->vid,
+							 info->db);
 
 	return 0;
 }
@@ -604,7 +633,7 @@ static int dsa_switch_mdb_add(struct dsa_switch *ds,
 	if (!ds->ops->port_mdb_add)
 		return -EOPNOTSUPP;
 
-	return dsa_port_do_mdb_add(dp, info->mdb);
+	return dsa_port_do_mdb_add(dp, info->mdb, info->db);
 }
 
 static int dsa_switch_mdb_del(struct dsa_switch *ds,
@@ -616,7 +645,7 @@ static int dsa_switch_mdb_del(struct dsa_switch *ds,
 	if (!ds->ops->port_mdb_del)
 		return -EOPNOTSUPP;
 
-	return dsa_port_do_mdb_del(dp, info->mdb);
+	return dsa_port_do_mdb_del(dp, info->mdb, info->db);
 }
 
 static int dsa_switch_host_mdb_add(struct dsa_switch *ds,
@@ -631,7 +660,7 @@ static int dsa_switch_host_mdb_add(struct dsa_switch *ds,
 	dsa_switch_for_each_port(dp, ds) {
 		if (dsa_port_host_address_match(dp, info->sw_index,
 						info->port)) {
-			err = dsa_port_do_mdb_add(dp, info->mdb);
+			err = dsa_port_do_mdb_add(dp, info->mdb, info->db);
 			if (err)
 				break;
 		}
@@ -652,7 +681,7 @@ static int dsa_switch_host_mdb_del(struct dsa_switch *ds,
 	dsa_switch_for_each_port(dp, ds) {
 		if (dsa_port_host_address_match(dp, info->sw_index,
 						info->port)) {
-			err = dsa_port_do_mdb_del(dp, info->mdb);
+			err = dsa_port_do_mdb_del(dp, info->mdb, info->db);
 			if (err)
 				break;
 		}