ipip: 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>
Acked-by: Eric Dumazet <edumazet@google.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 5db5942..ccb21d5 100644
--- a/include/uapi/linux/if_tunnel.h
+++ b/include/uapi/linux/if_tunnel.h
@@ -37,6 +37,17 @@
 	struct iphdr		iph;
 };
 
+enum {
+	IFLA_IPTUN_UNSPEC,
+	IFLA_IPTUN_LINK,
+	IFLA_IPTUN_LOCAL,
+	IFLA_IPTUN_REMOTE,
+	IFLA_IPTUN_TTL,
+	IFLA_IPTUN_TOS,
+	__IFLA_IPTUN_MAX,
+};
+#define IFLA_IPTUN_MAX	(__IFLA_IPTUN_MAX - 1)
+
 /* SIT-mode i_flags */
 #define	SIT_ISATAP	0x0001