net: bridge: Handle NETDEV_PRE_CHANGEADDR from ports

When a port device seeks approval of a potential new MAC address, make
sure that should the bridge device end up using this address, all
interested parties would agree with it.
Signed-off-by: Petr Machata <petrm@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br.c

@@ -31,6 +31,8 @@
  */
 static int br_device_event(struct notifier_block *unused, unsigned long event, void *ptr)
 {
+	struct netlink_ext_ack *extack = netdev_notifier_info_to_extack(ptr);
+	struct netdev_notifier_pre_changeaddr_info *prechaddr_info;
 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 	struct net_bridge_port *p;
 	struct net_bridge *br;
@@ -56,6 +58,17 @@ static int br_device_event(struct notifier_block *unused, unsigned long event, v
 		br_mtu_auto_adjust(br);
 		break;
 
+	case NETDEV_PRE_CHANGEADDR:
+		if (br->dev->addr_assign_type == NET_ADDR_SET)
+			break;
+		prechaddr_info = ptr;
+		err = dev_pre_changeaddr_notify(br->dev,
+						prechaddr_info->dev_addr,
+						extack);
+		if (err)
+			return notifier_from_errno(err);
+		break;
+
 	case NETDEV_CHANGEADDR:
 		spin_lock_bh(&br->lock);
 		br_fdb_changeaddr(p, dev->dev_addr);