bridge: Don't use VID 0 and 4095 in vlan filtering

IEEE 802.1Q says that:
- VID 0 shall not be configured as a PVID, or configured in any Filtering
Database entry.
- VID 4095 shall not be configured as a PVID, or transmitted in a tag
header. This VID value may be used to indicate a wildcard match for the VID
in management operations or Filtering Database entries.
(See IEEE 802.1Q-2011 6.9.1 and Table 9-2)

Don't accept adding these VIDs in the vlan_filtering implementation.

Signed-off-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Reviewed-by: Vlad Yasevich <vyasevic@redhat.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_fdb.c

@@ -700,7 +700,7 @@ int br_fdb_add(struct ndmsg *ndm, struct nlattr *tb[],
 
 		vid = nla_get_u16(tb[NDA_VLAN]);
 
-		if (vid >= VLAN_N_VID) {
+		if (!vid || vid >= VLAN_VID_MASK) {
 			pr_info("bridge: RTM_NEWNEIGH with invalid vlan id %d\n",
 				vid);
 			return -EINVAL;
@@ -794,7 +794,7 @@ int br_fdb_delete(struct ndmsg *ndm, struct nlattr *tb[],
 
 		vid = nla_get_u16(tb[NDA_VLAN]);
 
-		if (vid >= VLAN_N_VID) {
+		if (!vid || vid >= VLAN_VID_MASK) {
 			pr_info("bridge: RTM_NEWNEIGH with invalid vlan id %d\n",
 				vid);
 			return -EINVAL;

net/bridge/br_netlink.c

@@ -243,7 +243,7 @@ static int br_afspec(struct net_bridge *br,
 
 		vinfo = nla_data(tb[IFLA_BRIDGE_VLAN_INFO]);
 
-		if (vinfo->vid >= VLAN_N_VID)
+		if (!vinfo->vid || vinfo->vid >= VLAN_VID_MASK)
 			return -EINVAL;
 
 		switch (cmd) {

net/bridge/br_vlan.c

@@ -45,7 +45,6 @@ static int __vlan_add(struct net_port_vlans *v, u16 vid, u16 flags)
 		return 0;
 	}
 
-	if (vid) {
 	if (v->port_idx) {
 		p = v->parent.port;
 		br = p->br;
@@ -76,8 +75,6 @@ static int __vlan_add(struct net_port_vlans *v, u16 vid, u16 flags)
 		goto out_filt;
 	}
 
-	}
-
 	set_bit(vid, v->vlan_bitmap);
 	v->num_vlans++;
 	__vlan_add_flags(v, vid, flags);
@@ -98,7 +95,7 @@ static int __vlan_del(struct net_port_vlans *v, u16 vid)
 	__vlan_delete_pvid(v, vid);
 	clear_bit(vid, v->untagged_bitmap);
 
-	if (v->port_idx && vid) {
+	if (v->port_idx) {
 		struct net_device *dev = v->parent.port->dev;
 		const struct net_device_ops *ops = dev->netdev_ops;
 
@@ -248,7 +245,9 @@ bool br_allowed_egress(struct net_bridge *br,
 	return false;
 }
 
-/* Must be protected by RTNL */
+/* Must be protected by RTNL.
+ * Must be called with vid in range from 1 to 4094 inclusive.
+ */
 int br_vlan_add(struct net_bridge *br, u16 vid, u16 flags)
 {
 	struct net_port_vlans *pv = NULL;
@@ -278,7 +277,9 @@ out:
 	return err;
 }
 
-/* Must be protected by RTNL */
+/* Must be protected by RTNL.
+ * Must be called with vid in range from 1 to 4094 inclusive.
+ */
 int br_vlan_delete(struct net_bridge *br, u16 vid)
 {
 	struct net_port_vlans *pv;
@@ -289,14 +290,9 @@ int br_vlan_delete(struct net_bridge *br, u16 vid)
 	if (!pv)
 		return -EINVAL;
 
-	if (vid) {
-		/* If the VID !=0 remove fdb for this vid. VID 0 is special
-		 * in that it's the default and is always there in the fdb.
-		 */
 	spin_lock_bh(&br->hash_lock);
 	fdb_delete_by_addr(br, br->dev->dev_addr, vid);
 	spin_unlock_bh(&br->hash_lock);
-	}
 
 	__vlan_del(pv, vid);
 	return 0;
@@ -329,7 +325,9 @@ unlock:
 	return 0;
 }
 
-/* Must be protected by RTNL */
+/* Must be protected by RTNL.
+ * Must be called with vid in range from 1 to 4094 inclusive.
+ */
 int nbp_vlan_add(struct net_bridge_port *port, u16 vid, u16 flags)
 {
 	struct net_port_vlans *pv = NULL;
@@ -363,7 +361,9 @@ clean_up:
 	return err;
 }
 
-/* Must be protected by RTNL */
+/* Must be protected by RTNL.
+ * Must be called with vid in range from 1 to 4094 inclusive.
+ */
 int nbp_vlan_delete(struct net_bridge_port *port, u16 vid)
 {
 	struct net_port_vlans *pv;
@@ -374,14 +374,9 @@ int nbp_vlan_delete(struct net_bridge_port *port, u16 vid)
 	if (!pv)
 		return -EINVAL;
 
-	if (vid) {
-		/* If the VID !=0 remove fdb for this vid. VID 0 is special
-		 * in that it's the default and is always there in the fdb.
-		 */
 	spin_lock_bh(&port->br->hash_lock);
 	fdb_delete_by_addr(port->br, port->dev->dev_addr, vid);
 	spin_unlock_bh(&port->br->hash_lock);
-	}
 
 	return __vlan_del(pv, vid);
 }