IPVS: Extend protocol DNAT/SNAT and state handlers

Extend protocol DNAT/SNAT and state handlers to work with IPv6. Also
change/introduce new checksumming helper functions for this.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
index 68f004f..c173f1a 100644
--- a/include/net/ip_vs.h
+++ b/include/net/ip_vs.h
@@ -904,6 +904,17 @@
 	return csum_partial((char *) diff, sizeof(diff), oldsum);
 }
 
+#ifdef CONFIG_IP_VS_IPV6
+static inline __wsum ip_vs_check_diff16(const __be32 *old, const __be32 *new,
+					__wsum oldsum)
+{
+	__be32 diff[8] = { ~old[3], ~old[2], ~old[1], ~old[0],
+			    new[3],  new[2],  new[1],  new[0] };
+
+	return csum_partial((char *) diff, sizeof(diff), oldsum);
+}
+#endif
+
 static inline __wsum ip_vs_check_diff2(__be16 old, __be16 new, __wsum oldsum)
 {
 	__be16 diff[2] = { ~old, new };