bond: have random dev address by default instead of zeroes

Makes more sense to have randomly generated address by default than to
have all zeroes. It also allows user to for example put the bond into
bridge without need to have any slaves in it.

Also note that this changes only behaviour of bonds with no slaves. Once
the first slave device is enslaved, its address will be used (no change
here).

Also, fix dev_assign_type values on the way.

Reported-by: Pavel Šimerda <psimerda@redhat.com>
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 564cf42..b38c9bf 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1320,14 +1320,15 @@
 
 /*---------------------------------- IOCTL ----------------------------------*/
 
-static int bond_sethwaddr(struct net_device *bond_dev,
-			  struct net_device *slave_dev)
+static void bond_set_dev_addr(struct net_device *bond_dev,
+			      struct net_device *slave_dev)
 {
 	pr_debug("bond_dev=%p\n", bond_dev);
 	pr_debug("slave_dev=%p\n", slave_dev);
 	pr_debug("slave_dev->addr_len=%d\n", slave_dev->addr_len);
 	memcpy(bond_dev->dev_addr, slave_dev->dev_addr, slave_dev->addr_len);
-	return 0;
+	bond_dev->addr_assign_type = NET_ADDR_SET;
+	call_netdevice_notifiers(NETDEV_CHANGEADDR, bond_dev);
 }
 
 static netdev_features_t bond_fix_features(struct net_device *dev,
@@ -1628,10 +1629,8 @@
 
 	/* If this is the first slave, then we need to set the master's hardware
 	 * address to be the same as the slave's. */
-	if (is_zero_ether_addr(bond->dev->dev_addr))
-		memcpy(bond->dev->dev_addr, slave_dev->dev_addr,
-		       slave_dev->addr_len);
-
+	if (bond->dev_addr_from_first)
+		bond_set_dev_addr(bond->dev, slave_dev);
 
 	new_slave = kzalloc(sizeof(struct slave), GFP_KERNEL);
 	if (!new_slave) {
@@ -2048,12 +2047,8 @@
 
 	if (bond->slave_cnt == 0) {
 		bond_set_carrier(bond);
-
-		/* if the last slave was removed, zero the mac address
-		 * of the master so it will be set by the application
-		 * to the mac address of the first slave
-		 */
-		memset(bond_dev->dev_addr, 0, bond_dev->addr_len);
+		eth_hw_addr_random(bond_dev);
+		bond->dev_addr_from_first = true;
 
 		if (bond_vlan_used(bond)) {
 			pr_warning("%s: Warning: clearing HW address of %s while it still has VLANs.\n",
@@ -2234,11 +2229,8 @@
 		write_lock_bh(&bond->lock);
 	}
 
-	/* zero the mac address of the master so it will be
-	 * set by the application to the mac address of the
-	 * first slave
-	 */
-	memset(bond_dev->dev_addr, 0, bond_dev->addr_len);
+	eth_hw_addr_random(bond_dev);
+	bond->dev_addr_from_first = true;
 
 	if (bond_vlan_used(bond)) {
 		pr_warning("%s: Warning: clearing HW address of %s while it still has VLANs.\n",
@@ -3708,7 +3700,8 @@
 			break;
 		case BOND_SETHWADDR_OLD:
 		case SIOCBONDSETHWADDR:
-			res = bond_sethwaddr(bond_dev, slave_dev);
+			bond_set_dev_addr(bond_dev, slave_dev);
+			res = 0;
 			break;
 		case BOND_CHANGE_ACTIVE_OLD:
 		case SIOCBONDCHANGEACTIVE:
@@ -4858,6 +4851,13 @@
 
 	bond_debug_register(bond);
 
+	/* Ensure valid dev_addr */
+	if (is_zero_ether_addr(bond_dev->dev_addr) &&
+	    bond_dev->addr_assign_type == NET_ADDR_PERM) {
+		eth_hw_addr_random(bond_dev);
+		bond->dev_addr_from_first = true;
+	}
+
 	__hw_addr_init(&bond->mc_list);
 	return 0;
 }