+static void veth_change_state(struct net_device *dev)
+{
+ struct net_device *peer;
+ struct veth_priv *priv;
+
+ priv = netdev_priv(dev);
+ peer = priv->peer;
+
+ if (netif_carrier_ok(peer)) {
+ if (!netif_carrier_ok(dev))
+ netif_carrier_on(dev);
+ } else {
+ if (netif_carrier_ok(dev))
+ netif_carrier_off(dev);
+ }
+}
+
+static int veth_device_event(struct notifier_block *unused,
+ unsigned long event, void *ptr)
+{
+ struct net_device *dev = ptr;
+
+ if (dev->open != veth_open)
+ goto out;
+
+ switch (event) {
+ case NETDEV_CHANGE:
+ veth_change_state(dev);
+ break;
+ }
+out:
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block veth_notifier_block __read_mostly = {
+ .notifier_call = veth_device_event,
+};
+