bridge: notify applications if address of bridge device changes

The mac address of the bridge device may be changed when a new interface
is added to the bridge. If this happens, then the bridge needs to call
the network notifiers to tickle any other systems that care. Since bridge
can be a module, this also means exporting the notifier function.

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

3 files changed, 12 insertions, 5 deletions

diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index dce8f0009a12..718b60366dfe 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -389,6 +389,7 @@ int br_add_if(struct net_bridge *br, struct net_device *dev)
 {
         struct net_bridge_port *p;
         int err = 0;
+        bool changed_addr;
 
         /* Don't allow bridging non-ethernet like devices */
         if ((dev->flags & IFF_LOOPBACK) ||
@@ -446,7 +447,7 @@ int br_add_if(struct net_bridge *br, struct net_device *dev)
         list_add_rcu(&p->list, &br->port_list);
 
         spin_lock_bh(&br->lock);
-        br_stp_recalculate_bridge_id(br);
+        changed_addr = br_stp_recalculate_bridge_id(br);
         br_features_recompute(br);
 
         if ((dev->flags & IFF_UP) && netif_carrier_ok(dev) &&
@@ -456,6 +457,9 @@ int br_add_if(struct net_bridge *br, struct net_device *dev)
 
         br_ifinfo_notify(RTM_NEWLINK, p);
 
+        if (changed_addr)
+                call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
+
         dev_set_mtu(br->dev, br_min_mtu(br));
 
         kobject_uevent(&p->kobj, KOBJ_ADD);
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 19e2f46ed086..387013d33745 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -497,7 +497,7 @@ extern void br_stp_disable_bridge(struct net_bridge *br);
 extern void br_stp_set_enabled(struct net_bridge *br, unsigned long val);
 extern void br_stp_enable_port(struct net_bridge_port *p);
 extern void br_stp_disable_port(struct net_bridge_port *p);
-extern void br_stp_recalculate_bridge_id(struct net_bridge *br);
+extern bool br_stp_recalculate_bridge_id(struct net_bridge *br);
 extern void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *a);
 extern void br_stp_set_bridge_priority(struct net_bridge *br,
                                        u16 newprio);
diff --git a/net/bridge/br_stp_if.c b/net/bridge/br_stp_if.c
index 79372d4a4055..5593f5aec942 100644
--- a/net/bridge/br_stp_if.c
+++ b/net/bridge/br_stp_if.c
@@ -204,7 +204,7 @@ void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
 
 /* called under bridge lock */
-void br_stp_recalculate_bridge_id(struct net_bridge *br)
+bool br_stp_recalculate_bridge_id(struct net_bridge *br)
 {
         const unsigned char *br_mac_zero =
                         (const unsigned char *)br_mac_zero_aligned;
@@ -222,8 +222,11 @@ void br_stp_recalculate_bridge_id(struct net_bridge *br)
 
         }
 
-        if (compare_ether_addr(br->bridge_id.addr, addr))
-                br_stp_change_bridge_id(br, addr);
+        if (compare_ether_addr(br->bridge_id.addr, addr) == 0)
+                return false;   /* no change */
+
+        br_stp_change_bridge_id(br, addr);
+        return true;
 }
 
 /* called under bridge lock */