fix: refactored routing logic (fixes #701)

routing/tables.go

@@ -0,0 +1,39 @@
+package routing
+
+import "sync"
+
+var (
+	lock  = sync.RWMutex{}
+	table = make([]Route, 0)
+)
+
+func Table() []Route {
+	lock.RLock()
+	defer lock.RUnlock()
+	return table
+}
+
+func Update() ([]Route, error) {
+	lock.Lock()
+	defer lock.Unlock()
+	return update()
+}
+
+func Gateway(ip RouteType, device string) (string, error) {
+	Update()
+
+	lock.RLock()
+	defer lock.RUnlock()
+
+	for _, r := range table {
+		if r.Type == ip {
+			if device == "" || r.Device == device || r.Device == "" /* windows case */ {
+				if r.Default {
+					return r.Gateway, nil
+				}
+			}
+		}
+	}
+
+	return "", nil
+}