openvswitch: add tunnel protocol to sw_flow_key

Store tunnel protocol (AF_INET or AF_INET6) in sw_flow_key. This field now
also acts as an indicator whether the flow contains tunnel data (this was
previously indicated by tun_key.u.ipv4.dst being set but with IPv6 addresses
in an union with IPv4 ones this won't work anymore).

The new field was added to a hole in sw_flow_key.

Signed-off-by: Jiri Benc <jbenc@redhat.com>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/openvswitch/flow.h b/net/openvswitch/flow.h
index fe527d2..5688e33 100644
--- a/net/openvswitch/flow.h
+++ b/net/openvswitch/flow.h
@@ -63,6 +63,7 @@
 		u32	skb_mark;	/* SKB mark. */
 		u16	in_port;	/* Input switch port (or DP_MAX_PORTS). */
 	} __packed phy; /* Safe when right after 'tun_key'. */
+	u8 tun_proto;			/* Protocol of encapsulating tunnel. */
 	u32 ovs_flow_hash;		/* Datapath computed hash value.  */
 	u32 recirc_id;			/* Recirculation ID.  */
 	struct {