[BRIDGE]: allow show/store of group multicast address

Bridge's communicate with each other using Spanning Tree Protocol
over a standard multicast address. There are times when testing or
layering bridges over existing topologies or tunnels, when it is
useful to use alternative multicast addresses for STP packets.

The 802.1d standard has some unused addresses, that can be used for this.
This patch is restrictive in that it only allows one of the possible
addresses in the standard.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 3bc9ad483473..86ecea7ed372 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -109,6 +109,7 @@ struct net_bridge
         unsigned long                   bridge_hello_time;
         unsigned long                   bridge_forward_delay;
 
+        u8                              group_addr[ETH_ALEN];
         u16                             root_port;
         unsigned char                   stp_enabled;
         unsigned char                   topology_change;
@@ -122,7 +123,7 @@ struct net_bridge
 };
 
 extern struct notifier_block br_device_notifier;
-extern const unsigned char bridge_ula[6];
+extern const u8 br_group_address[ETH_ALEN];
 
 /* called under bridge lock */
 static inline int br_is_root_bridge(const struct net_bridge *br)