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

@@ -45,37 +45,34 @@ 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;
-			dev = p->dev;
-		} else {
-			br = v->parent.br;
-			dev = br->dev;
-		}
-		ops = dev->netdev_ops;
+	if (v->port_idx) {
+		p = v->parent.port;
+		br = p->br;
+		dev = p->dev;
+	} else {
+		br = v->parent.br;
+		dev = br->dev;
+	}
+	ops = dev->netdev_ops;
 
-		if (p && (dev->features & NETIF_F_HW_VLAN_CTAG_FILTER)) {
-			/* Add VLAN to the device filter if it is supported.
-			 * Stricly speaking, this is not necessary now, since
-			 * devices are made promiscuous by the bridge, but if
-			 * that ever changes this code will allow tagged
-			 * traffic to enter the bridge.
-			 */
-			err = ops->ndo_vlan_rx_add_vid(dev, htons(ETH_P_8021Q),
-						       vid);
-			if (err)
-				return err;
-		}
-
-		err = br_fdb_insert(br, p, dev->dev_addr, vid);
-		if (err) {
-			br_err(br, "failed insert local address into bridge "
-			       "forwarding table\n");
-			goto out_filt;
-		}
+	if (p && (dev->features & NETIF_F_HW_VLAN_CTAG_FILTER)) {
+		/* Add VLAN to the device filter if it is supported.
+		 * Stricly speaking, this is not necessary now, since
+		 * devices are made promiscuous by the bridge, but if
+		 * that ever changes this code will allow tagged
+		 * traffic to enter the bridge.
+		 */
+		err = ops->ndo_vlan_rx_add_vid(dev, htons(ETH_P_8021Q),
+					       vid);
+		if (err)
+			return err;
+	}
 
+	err = br_fdb_insert(br, p, dev->dev_addr, vid);
+	if (err) {
+		br_err(br, "failed insert local address into bridge "
+		       "forwarding table\n");
+		goto out_filt;
 	}
 
 	set_bit(vid, v->vlan_bitmap);
@@ -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);
-	}
+	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);
-	}
+	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);
 }