openvswitch: Fix egress tunnel info.

While transitioning to netdev based vport we broke OVS
feature which allows user to retrieve tunnel packet egress
information for lwtunnel devices.  Following patch fixes it
by introducing ndo operation to get the tunnel egress info.
Same ndo operation can be used for lwtunnel devices and compat
ovs-tnl-vport devices. So after adding such device operation
we can remove similar operation from ovs-vport.

Fixes: 614732eaa12d ("openvswitch: Use regular VXLAN net_device device").
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 2d15e38..210d11a 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1054,6 +1054,10 @@
  *	This function is used to pass protocol port error state information
  *	to the switch driver. The switch driver can react to the proto_down
  *      by doing a phys down on the associated switch port.
+ * int (*ndo_fill_metadata_dst)(struct net_device *dev, struct sk_buff *skb);
+ *	This function is used to get egress tunnel information for given skb.
+ *	This is useful for retrieving outer tunnel header parameters while
+ *	sampling packet.
  *
  */
 struct net_device_ops {
@@ -1227,6 +1231,8 @@
 	int			(*ndo_get_iflink)(const struct net_device *dev);
 	int			(*ndo_change_proto_down)(struct net_device *dev,
 							 bool proto_down);
+	int			(*ndo_fill_metadata_dst)(struct net_device *dev,
+						       struct sk_buff *skb);
 };
 
 /**
@@ -2203,6 +2209,7 @@
 void dev_remove_offload(struct packet_offload *po);
 
 int dev_get_iflink(const struct net_device *dev);
+int dev_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb);
 struct net_device *__dev_get_by_flags(struct net *net, unsigned short flags,
 				      unsigned short mask);
 struct net_device *dev_get_by_name(struct net *net, const char *name);