tproxy: added tproxy sockopt interface in the IPV6 layer

Support for IPV6_RECVORIGDSTADDR sockopt for UDP sockets were contributed by
Harry Mason.

Signed-off-by: Balazs Scheidler <bazsi@balabit.hu>
Signed-off-by: KOVACS Krisztian <hidden@balabit.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index e62683b..8e429d0 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -341,7 +341,9 @@
 				odstopts:1,
                                 rxflow:1,
 				rxtclass:1,
-				rxpmtu:1;
+				rxpmtu:1,
+				rxorigdstaddr:1;
+				/* 2 bits hole */
 		} bits;
 		__u16		all;
 	} rxopt;