[SK_BUFF]: Introduce skb_mac_header()

For the places where we need a pointer to the mac header, it is still legal to
touch skb->mac.raw directly if just adding to, subtracting from or setting it
to another layer header.

This one also converts some more cases to skb_reset_mac_header() that my
regex missed as it had no spaces before nor after '=', ugh.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 29ee7be..486ab93 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1698,9 +1698,9 @@
 		printk(KERN_WARNING "martian source %u.%u.%u.%u from "
 			"%u.%u.%u.%u, on dev %s\n",
 			NIPQUAD(daddr), NIPQUAD(saddr), dev->name);
-		if (dev->hard_header_len && skb->mac.raw) {
+		if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
 			int i;
-			unsigned char *p = skb->mac.raw;
+			const unsigned char *p = skb_mac_header(skb);
 			printk(KERN_WARNING "ll header: ");
 			for (i = 0; i < dev->hard_header_len; i++, p++) {
 				printk("%02x", *p);