bridge: Support 802.1ad vlan filtering

This enables us to change the vlan protocol for vlan filtering.
We come to be able to filter frames on the basis of 802.1ad vlan tags
through a bridge.

This also changes br->group_addr if it has not been set by user.
This is needed for an 802.1ad bridge.
(See IEEE 802.1Q-2011 8.13.5.)

Furthermore, this sets br->group_fwd_mask_required so that an 802.1ad
bridge can forward the Nearest Customer Bridge group addresses except
for br->group_addr, which should be passed to higher layer.

To change the vlan protocol, write a protocol in sysfs:
# echo 0x88a8 > /sys/class/net/br0/bridge/vlan_protocol

Signed-off-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_private.h

@@ -243,6 +243,7 @@ struct net_bridge
 	unsigned long			bridge_forward_delay;
 
 	u8				group_addr[ETH_ALEN];
+	bool				group_addr_set;
 	u16				root_port;
 
 	enum {
@@ -597,7 +598,9 @@ int br_vlan_add(struct net_bridge *br, u16 vid, u16 flags);
 int br_vlan_delete(struct net_bridge *br, u16 vid);
 void br_vlan_flush(struct net_bridge *br);
 bool br_vlan_find(struct net_bridge *br, u16 vid);
+void br_recalculate_fwd_mask(struct net_bridge *br);
 int br_vlan_filter_toggle(struct net_bridge *br, unsigned long val);
+int br_vlan_set_proto(struct net_bridge *br, unsigned long val);
 void br_vlan_init(struct net_bridge *br);
 int nbp_vlan_add(struct net_bridge_port *port, u16 vid, u16 flags);
 int nbp_vlan_delete(struct net_bridge_port *port, u16 vid);
@@ -694,6 +697,10 @@ static inline bool br_vlan_find(struct net_bridge *br, u16 vid)
 	return false;
 }
 
+static inline void br_recalculate_fwd_mask(struct net_bridge *br)
+{
+}
+
 static inline void br_vlan_init(struct net_bridge *br)
 {
 }