geneve: Add support to collect tunnel metadata.

Following patch create new tunnel flag which enable
tunnel metadata collection on given device. These devices
can be used by tunnel metadata based routing or by OVS.
Geneve Consolidation patch get rid of collect_md_tun to
simplify tunnel lookup further.
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Reviewed-by: Jesse Gross <jesse@nicira.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/geneve.h

@@ -96,6 +96,9 @@ int geneve_xmit_skb(struct geneve_sock *gs, struct rtable *rt,
 		    __u8 ttl, __be16 df, __be16 src_port, __be16 dst_port,
 		    __be16 tun_flags, u8 vni[3], u8 opt_len, u8 *opt,
 		    bool csum, bool xnet);
+
+struct net_device *geneve_dev_create_fb(struct net *net, const char *name,
+					u8 name_assign_type, u16 dst_port);
 #endif /*ifdef CONFIG_INET */
 
 #endif /*ifdef__NET_GENEVE_H */

include/uapi/linux/if_link.h

@@ -411,6 +411,7 @@ enum {
 	IFLA_GENEVE_TTL,
 	IFLA_GENEVE_TOS,
 	IFLA_GENEVE_PORT,	/* destination port */
+	IFLA_GENEVE_COLLECT_METADATA,
 	__IFLA_GENEVE_MAX
 };
 #define IFLA_GENEVE_MAX	(__IFLA_GENEVE_MAX - 1)