[NET]: Wrap hard_header_parse

Wrap the hard_header_parse function to simplify next step of
header_ops conversion.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index b33d084..aae9ec3 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -657,7 +657,7 @@
 	void			(*vlan_rx_kill_vid)(struct net_device *dev,
 						    unsigned short vid);
 
-	int			(*hard_header_parse)(struct sk_buff *skb,
+	int			(*hard_header_parse)(const struct sk_buff *skb,
 						     unsigned char *haddr);
 	int			(*neigh_setup)(struct net_device *dev, struct neigh_parms *);
 #ifdef CONFIG_NETPOLL
@@ -809,6 +809,16 @@
 	return dev->hard_header(skb, dev, type, daddr, saddr, len);
 }
 
+static inline int dev_parse_header(const struct sk_buff *skb,
+				   unsigned char *haddr)
+{
+	const struct net_device *dev = skb->dev;
+
+	if (!dev->hard_header_parse)
+		return 0;
+	return dev->hard_header_parse(skb, haddr);
+}
+
 typedef int gifconf_func_t(struct net_device * dev, char __user * bufptr, int len);
 extern int		register_gifconf(unsigned int family, gifconf_func_t * gifconf);
 static inline int unregister_gifconf(unsigned int family)