fix: multi issues - TUN read loop, SDWAN routing for TenantID=0, WS keepalive 10s

pkg/signal/conn.go

@@ -103,6 +103,33 @@ func (c *Conn) Request(mainType, subType uint16, payload interface{},
 
 // ReadLoop reads messages and dispatches to handlers. Blocks until error or Close().
 func (c *Conn) ReadLoop() error {
+	// keepalive to avoid idle close (read deadline = 3x ping interval)
+	_ = c.ws.SetReadDeadline(time.Now().Add(90 * time.Second))
+	c.ws.SetPongHandler(func(string) error {
+		_ = c.ws.SetReadDeadline(time.Now().Add(90 * time.Second))
+		return nil
+	})
+
+	// Send ping frames periodically to keep NAT/WSS alive
+	// Increased frequency to 10s for better resilience against network hiccups
+	go func() {
+		ticker := time.NewTicker(10 * time.Second)
+		defer ticker.Stop()
+		for {
+			select {
+			case <-c.quit:
+				return
+			case <-ticker.C:
+				c.writeMu.Lock()
+				_ = c.ws.SetWriteDeadline(time.Now().Add(5 * time.Second))
+				err := c.ws.WriteMessage(websocket.PingMessage, []byte(time.Now().Format("20060102150405")))
+				if err != nil {
+					log.Printf("[signal] ping failed: %v, will reconnect", err)
+				}
+				c.writeMu.Unlock()
+			}
+		}
+	}()
 	for {
 		_, msg, err := c.ws.ReadMessage()
 		if err != nil {