[NET]: Make mangling a checksum (0 -> 0xffff on the wire) explicit.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 9b21d67..c2e629d 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -536,8 +536,8 @@
 				   &fl->fl6_dst,
 				   total_len, fl->proto, tmp_csum);
 
-	if (tmp_csum == 0 && fl->proto == IPPROTO_UDP)
-		tmp_csum = -1;
+	if (csum == 0 && fl->proto == IPPROTO_UDP)
+		csum = CSUM_MANGLED_0;
 
 	if (skb_store_bits(skb, offset, &csum, 2))
 		BUG();
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 0d22008..bb45b9b 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -536,7 +536,7 @@
 	uh->check = csum_ipv6_magic(&fl->fl6_src, &fl->fl6_dst,
 				    up->len, fl->proto, csum   );
 	if (uh->check == 0)
-		uh->check = -1;
+		uh->check = CSUM_MANGLED_0;
 
 	err = ip6_push_pending_frames(sk);
 out: