Add a way to trigger punch backs via lighthouse (#394)

interface.go

@@ -61,7 +61,10 @@ type Interface struct {
 	dropMulticast      bool
 	udpBatchSize       int
 	routines           int
-	version            string
+
+	// rebindCount is used to decide if an active tunnel should trigger a punch notification through a lighthouse
+	rebindCount int8
+	version     string
 
 	conntrackCacheTimeout time.Duration