gtp-rtnl: and netns support

Signed-off-by: Andreas Schultz <aschultz@tpip.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/src/internal.h b/src/internal.h
index 75b3954..68f0135 100644
--- a/src/internal.h
+++ b/src/internal.h
@@ -13,6 +13,7 @@
 #include <netinet/in.h>
 
 struct gtp_tunnel {
+	int             ifns;
 	uint32_t	ifidx;
 	struct in_addr	ms_addr;
 	struct in_addr	sgsn_addr;