ip6tnl: advertise tunnel param via rtnl

It is usefull for daemons that monitor link event to have the full parameters of
these interfaces when a rtnl message is sent.
It allows also to dump them via rtnetlink.

It is based on what is done for GRE tunnels.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/uapi/linux/if_tunnel.h b/include/uapi/linux/if_tunnel.h
index ccb21d5..c1bf0b5 100644
--- a/include/uapi/linux/if_tunnel.h
+++ b/include/uapi/linux/if_tunnel.h
@@ -44,6 +44,9 @@
 	IFLA_IPTUN_REMOTE,
 	IFLA_IPTUN_TTL,
 	IFLA_IPTUN_TOS,
+	IFLA_IPTUN_ENCAP_LIMIT,
+	IFLA_IPTUN_FLOWINFO,
+	IFLA_IPTUN_FLAGS,
 	__IFLA_IPTUN_MAX,
 };
 #define IFLA_IPTUN_MAX	(__IFLA_IPTUN_MAX - 1)