extern int dev_close(struct net_device *dev);
extern int dev_queue_xmit(struct sk_buff *skb);
extern int register_netdevice(struct net_device *dev);
-extern int unregister_netdevice(struct net_device *dev);
+extern void unregister_netdevice(struct net_device *dev);
extern void free_netdev(struct net_device *dev);
extern void synchronize_net(void);
extern int register_netdevice_notifier(struct notifier_block *nb);