macvlan: fix the problem when mac address changes for passthru mode

The macvlan dev should always have the same mac address like lowerdev when in the passthru mode, change the mac address alone will break the work mechanism, so when the lowerdev or macvlan mac address changes, we should propagate the changes to another dev.

v1->v2: Allow macvlan dev to change mac address for passthru mode and propagate to
lowerdev.

Signed-off-by Ding Tianhong <[email protected]>

---
 drivers/net/macvlan.c | 42 +++++++++++++++++++++++++++++++++---------
 1 file changed, 33 insertions(+), 9 deletions(-)

drivers/net/macvlan.c +22 -9

index a665e90..3e24770 100644
@@ -494,35 +494,47 @@ hash_del:
 	return 0;
 }
 
-static int macvlan_set_mac_address(struct net_device *dev, void *p)
+static int macvlan_sync_address(struct net_device *dev, unsigned char *addr)
 {
 	struct macvlan_dev *vlan = netdev_priv(dev);
 	struct net_device *lowerdev = vlan->lowerdev;
-	struct sockaddr *addr = p;
 	int err;
 
-	if (!is_valid_ether_addr(addr->sa_data))
-		return -EADDRNOTAVAIL;
-
 	if (!(dev->flags & IFF_UP)) {
 		/* Just copy in the new address */
-		memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
+		ether_addr_copy(dev->dev_addr, addr);
 	} else {
 		/* Rehash and update the device filters */
-		if (macvlan_addr_busy(vlan->port, addr->sa_data))
+		if (macvlan_addr_busy(vlan->port, addr))
 			return -EBUSY;
 
-		err = dev_uc_add(lowerdev, addr->sa_data);
+		err = dev_uc_add(lowerdev, addr);
 		if (err)
 			return err;
 
 		dev_uc_del(lowerdev, dev->dev_addr);
 
-		macvlan_hash_change_addr(vlan, addr->sa_data);
+		macvlan_hash_change_addr(vlan, addr);
 	}
 	return 0;
 }
 
+static int macvlan_set_mac_address(struct net_device *dev, void *p)
+{
+	struct macvlan_dev *vlan = netdev_priv(dev);
+	struct sockaddr *addr = p;
+
+	if (!is_valid_ether_addr(addr->sa_data))
+		return -EADDRNOTAVAIL;
+
+	if (vlan->mode == MACVLAN_MODE_PASSTHRU) {
+		dev_set_mac_address(vlan->lowerdev, addr);
+		return 0;
+	}
+
+	return macvlan_sync_address(dev, addr->sa_data);
+}
+
 static void macvlan_change_rx_flags(struct net_device *dev, int change)
 {
 	struct macvlan_dev *vlan = netdev_priv(dev);

@@ -1106,6 +1118,18 @@ static int macvlan_device_event(struct notifier_block *unused,
 			dev_set_mtu(vlan->dev, dev->mtu);
 		}
 		break;
+	case NETDEV_CHANGEADDR:

drivers/net/macvlan.c +1 -0

+		break;
 	case NETDEV_UNREGISTER:
 		/* twiddle thumbs on netns device moves */
 		if (dev->reg_state != NETREG_UNREGISTERING)

Quoted 79 lines · Ding Tianhong

The macvlan dev should always have the same mac address like lowerdev when in the passthru mode, change the mac address alone will break the work mechanism, so when the lowerdev or macvlan mac address changes, we should propagate the changes to another dev.

v1->v2: Allow macvlan dev to change mac address for passthru mode and propagate to
lowerdev.

Signed-off-by Ding Tianhong <[email protected]>

---
 drivers/net/macvlan.c | 42 +++++++++++++++++++++++++++++++++---------
 1 file changed, 33 insertions(+), 9 deletions(-)

drivers/net/macvlan.c +22 -9

index a665e90..3e24770 100644
@@ -494,35 +494,47 @@ hash_del:
 	return 0;
 }
 
-static int macvlan_set_mac_address(struct net_device *dev, void *p)
+static int macvlan_sync_address(struct net_device *dev, unsigned char *addr)
 {
 	struct macvlan_dev *vlan = netdev_priv(dev);
 	struct net_device *lowerdev = vlan->lowerdev;
-	struct sockaddr *addr = p;
 	int err;
 
-	if (!is_valid_ether_addr(addr->sa_data))
-		return -EADDRNOTAVAIL;
-
 	if (!(dev->flags & IFF_UP)) {
 		/* Just copy in the new address */
-		memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
+		ether_addr_copy(dev->dev_addr, addr);
 	} else {
 		/* Rehash and update the device filters */
-		if (macvlan_addr_busy(vlan->port, addr->sa_data))
+		if (macvlan_addr_busy(vlan->port, addr))
 			return -EBUSY;
 
-		err = dev_uc_add(lowerdev, addr->sa_data);
+		err = dev_uc_add(lowerdev, addr);
 		if (err)
 			return err;
 
 		dev_uc_del(lowerdev, dev->dev_addr);
 
-		macvlan_hash_change_addr(vlan, addr->sa_data);
+		macvlan_hash_change_addr(vlan, addr);
 	}
 	return 0;
 }
 
+static int macvlan_set_mac_address(struct net_device *dev, void *p)
+{
+	struct macvlan_dev *vlan = netdev_priv(dev);
+	struct sockaddr *addr = p;
+
+	if (!is_valid_ether_addr(addr->sa_data))
+		return -EADDRNOTAVAIL;
+
+	if (vlan->mode == MACVLAN_MODE_PASSTHRU) {
+		dev_set_mac_address(vlan->lowerdev, addr);
+		return 0;
+	}
+
+	return macvlan_sync_address(dev, addr->sa_data);
+}
+
 static void macvlan_change_rx_flags(struct net_device *dev, int change)
 {
 	struct macvlan_dev *vlan = netdev_priv(dev);

@@ -1106,6 +1118,18 @@ static int macvlan_device_event(struct notifier_block *unused,
 			dev_set_mtu(vlan->dev, dev->mtu);
 		}
 		break;
+	case NETDEV_CHANGEADDR:

drivers/net/macvlan.c static int macvlan_device_event(struct notifier_block *unused, · line 1131

Quoted 10 lines

drivers/net/macvlan.c +10 -0

+		if (!port->passthru)
+			return NOTIFY_DONE;
+
+		vlan = list_first_entry_or_null(&port->vlans,
+						struct macvlan_dev,
+						list);
+
+		if (macvlan_sync_address(vlan->dev, dev->dev_addr))
+			return NOTIFY_BAD;
+

Ok, this is not quite right. The lower device changes it's mac address and notifies upper macvlan about it. Macvlan, if it is up, will write the same mac address down to the lower device's unicast address list as part of the sync. The lower device ends up with two copies of its own address.

-vlad

drivers/net/macvlan.c static int macvlan_device_event(struct notifier_block *unused, · line 1135

Quoted 5 lines

drivers/net/macvlan.c +1 -0

+		break;
 	case NETDEV_UNREGISTER:
 		/* twiddle thumbs on netns device moves */
 		if (dev->reg_state != NETREG_UNREGISTERING)

.