[NET]: Annotate checksums in on-the-wire packets.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/ip.h b/include/linux/ip.h
index ecee9bb..1d36b97 100644
--- a/include/linux/ip.h
+++ b/include/linux/ip.h
@@ -98,7 +98,7 @@
 	__be16	frag_off;
 	__u8	ttl;
 	__u8	protocol;
-	__be16	check;
+	__sum16	check;
 	__be32	saddr;
 	__be32	daddr;
 	/*The options start here. */