Fix the bind problem by just recreating the dev

TODO: WHY CANT WE REBIND TO A PORT - WE NEED TO FIX THIS BETTER

Author: oschwartz10612

clients.go

@@ -54,6 +54,13 @@ func setupClientsNetstack(client *websocket.Client, host string) {
 		}
 	})
 
+	wgService.SetOnNetstackClose(func() {
+		if wgTesterServer != nil {
+			wgTesterServer.Stop()
+			wgTesterServer = nil
+		}
+	})
+
 	client.OnTokenUpdate(func(token string) {
 		wgService.SetToken(token)
 	})

proxy/manager.go

@@ -191,13 +191,13 @@ func (pm *ProxyManager) Stop() error {
 		pm.udpConns = append(pm.udpConns[:i], pm.udpConns[i+1:]...)
 	}
 
-	// Clear the target maps
-	for k := range pm.tcpTargets {
-		delete(pm.tcpTargets, k)
-	}
-	for k := range pm.udpTargets {
-		delete(pm.udpTargets, k)
-	}
+	// // Clear the target maps
+	// for k := range pm.tcpTargets {
+	// 	delete(pm.tcpTargets, k)
+	// }
+	// for k := range pm.udpTargets {
+	// 	delete(pm.udpTargets, k)
+	// }
 
 	// Give active connections a chance to close gracefully
 	time.Sleep(100 * time.Millisecond)
@@ -368,3 +368,23 @@ func (pm *ProxyManager) handleUDPProxy(conn *gonet.UDPConn, targetAddr string) {
 		}
 	}
 }
+
+// write a function to print out the current targets in the ProxyManager
+func (pm *ProxyManager) PrintTargets() {
+	pm.mutex.RLock()
+	defer pm.mutex.RUnlock()
+
+	logger.Info("Current TCP Targets:")
+	for listenIP, targets := range pm.tcpTargets {
+		for port, targetAddr := range targets {
+			logger.Info("TCP %s:%d -> %s", listenIP, port, targetAddr)
+		}
+	}
+
+	logger.Info("Current UDP Targets:")
+	for listenIP, targets := range pm.udpTargets {
+		for port, targetAddr := range targets {
+			logger.Info("UDP %s:%d -> %s", listenIP, port, targetAddr)
+		}
+	}
+}

wgnetstack/wgnetstack.go

@@ -85,6 +85,8 @@ type WireGuardService struct {
 	dns    []netip.Addr
 	// Callback for when netstack is ready
 	onNetstackReady func(*netstack.Net)
+	// Callback for when netstack is closed
+	onNetstackClose func()
 	othertnet       *netstack.Net
 	// Proxy manager for tunnel
 	proxyManager *proxy.ProxyManager
@@ -254,7 +256,7 @@ func (s *WireGuardService) addTcpTarget(msg websocket.WSMessage) {
 	}
 
 	if len(targetData.Targets) > 0 {
-		updateTargets(s.proxyManager, "add", s.TunnelIP, "tcp", targetData)
+		s.updateTargets(s.proxyManager, "add", s.TunnelIP, "tcp", targetData)
 	}
 }
 
@@ -274,7 +276,7 @@ func (s *WireGuardService) addUdpTarget(msg websocket.WSMessage) {
 	}
 
 	if len(targetData.Targets) > 0 {
-		updateTargets(s.proxyManager, "add", s.TunnelIP, "udp", targetData)
+		s.updateTargets(s.proxyManager, "add", s.TunnelIP, "udp", targetData)
 	}
 }
 
@@ -294,7 +296,7 @@ func (s *WireGuardService) removeUdpTarget(msg websocket.WSMessage) {
 	}
 
 	if len(targetData.Targets) > 0 {
-		updateTargets(s.proxyManager, "remove", s.TunnelIP, "udp", targetData)
+		s.updateTargets(s.proxyManager, "remove", s.TunnelIP, "udp", targetData)
 	}
 }
 
@@ -314,7 +316,7 @@ func (s *WireGuardService) removeTcpTarget(msg websocket.WSMessage) {
 	}
 
 	if len(targetData.Targets) > 0 {
-		updateTargets(s.proxyManager, "remove", s.TunnelIP, "tcp", targetData)
+		s.updateTargets(s.proxyManager, "remove", s.TunnelIP, "tcp", targetData)
 	}
 }
 
@@ -392,6 +394,10 @@ func (s *WireGuardService) SetOnNetstackReady(callback func(*netstack.Net)) {
 	s.onNetstackReady = callback
 }
 
+func (s *WireGuardService) SetOnNetstackClose(callback func()) {
+	s.onNetstackClose = callback
+}
+
 func (s *WireGuardService) LoadRemoteConfig() error {
 	s.stopGetConfig = s.client.SendMessageInterval("newt/wg/get-config", map[string]interface{}{
 		"publicKey": s.key.PublicKey().String(),
@@ -438,11 +444,11 @@ func (s *WireGuardService) handleConfig(msg websocket.WSMessage) {
 
 	// add the targets if there are any
 	if len(config.Targets.TCP) > 0 {
-		updateTargets(s.proxyManager, "add", s.TunnelIP, "tcp", TargetData{Targets: config.Targets.TCP})
+		s.updateTargets(s.proxyManager, "add", s.TunnelIP, "tcp", TargetData{Targets: config.Targets.TCP})
 	}
 
 	if len(config.Targets.UDP) > 0 {
-		updateTargets(s.proxyManager, "add", s.TunnelIP, "udp", TargetData{Targets: config.Targets.UDP})
+		s.updateTargets(s.proxyManager, "add", s.TunnelIP, "udp", TargetData{Targets: config.Targets.UDP})
 	}
 
 	// Create ProxyManager for this tunnel
@@ -1077,7 +1083,8 @@ func (s *WireGuardService) keepSendingUDPHolePunch(host string) {
 	}
 }
 
-func updateTargets(pm *proxy.ProxyManager, action string, tunnelIP string, proto string, targetData TargetData) error {
+func (s *WireGuardService) updateTargets(pm *proxy.ProxyManager, action string, tunnelIP string, proto string, targetData TargetData) error {
+	var replace = true
 	for _, t := range targetData.Targets {
 		// Split the first number off of the target with : separator and use as the port
 		parts := strings.Split(t, ":")
@@ -1106,6 +1113,8 @@ func updateTargets(pm *proxy.ProxyManager, action string, tunnelIP string, proto
 				// Ignore "target not found" errors as this is expected for new targets
 				if !strings.Contains(err.Error(), "target not found") {
 					logger.Error("Failed to remove existing target: %v", err)
+				} else {
+					replace = false // If we got here, it means the target didn't exist, so we can add it without replacing
 				}
 			}
 
@@ -1123,6 +1132,17 @@ func updateTargets(pm *proxy.ProxyManager, action string, tunnelIP string, proto
 		}
 	}
 
+	if replace {
+		// If we replaced any targets, we need to hot swap the netstack
+		if err := s.ReplaceNetstack(s.dns); err != nil {
+			logger.Error("Failed to replace netstack after updating targets: %v", err)
+			return err
+		}
+		logger.Info("Netstack replaced successfully after updating targets")
+	} else {
+		logger.Info("No targets updated, no netstack replacement needed")
+	}
+
 	return nil
 }
 
@@ -1140,3 +1160,127 @@ func parseTargetData(data interface{}) (TargetData, error) {
 	}
 	return targetData, nil
 }
+
+// Add this method to WireGuardService
+func (s *WireGuardService) ReplaceNetstack(newDNS []netip.Addr) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	if s.device == nil || s.tun == nil {
+		return fmt.Errorf("WireGuard device not initialized")
+	}
+
+	// Parse the current tunnel IP from the existing config
+	parts := strings.Split(s.config.IpAddress, "/")
+	if len(parts) != 2 {
+		return fmt.Errorf("invalid IP address format: %s", s.config.IpAddress)
+	}
+	tunnelIP := netip.MustParseAddr(parts[0])
+
+	// Stop the proxy manager temporarily
+	s.proxyManager.Stop()
+
+	// Create new TUN device and netstack with new DNS
+	newTun, newTnet, err := netstack.CreateNetTUN(
+		[]netip.Addr{tunnelIP},
+		newDNS,
+		s.mtu)
+	if err != nil {
+		// Restart proxy manager with old tnet on failure
+		s.proxyManager.Start()
+		return fmt.Errorf("failed to create new TUN device: %v", err)
+	}
+
+	// Get current device config before closing
+	currentConfig, err := s.device.IpcGet()
+	if err != nil {
+		newTun.Close()
+		s.proxyManager.Start()
+		return fmt.Errorf("failed to get current device config: %v", err)
+	}
+
+	// Filter out read-only fields from the config
+	filteredConfig := s.filterReadOnlyFields(currentConfig)
+
+	// if onNetstackClose callback is set, call it
+	if s.onNetstackClose != nil {
+		s.onNetstackClose()
+	}
+
+	// Close old device (this closes the old TUN device)
+	s.device.Close()
+
+	// Update references
+	s.tun = newTun
+	s.tnet = newTnet
+	s.dns = newDNS
+
+	// Create new WireGuard device with same port
+	s.device = device.NewDevice(s.tun, NewFixedPortBind(s.Port), device.NewLogger(
+		device.LogLevelSilent,
+		"wireguard: ",
+	))
+
+	// Restore the configuration (without read-only fields)
+	err = s.device.IpcSet(filteredConfig)
+	if err != nil {
+		return fmt.Errorf("failed to restore WireGuard configuration: %v", err)
+	}
+
+	// Bring up the device
+	err = s.device.Up()
+	if err != nil {
+		return fmt.Errorf("failed to bring up new WireGuard device: %v", err)
+	}
+
+	// Update proxy manager with new tnet and restart
+	s.proxyManager.SetTNet(s.tnet)
+	s.proxyManager.Start()
+
+	s.proxyManager.PrintTargets()
+
+	// Call the netstack ready callback if set
+	if s.onNetstackReady != nil {
+		go s.onNetstackReady(s.tnet)
+	}
+
+	logger.Info("Netstack replaced successfully with new DNS servers")
+	return nil
+}
+
+// filterReadOnlyFields removes read-only fields from WireGuard IPC configuration
+func (s *WireGuardService) filterReadOnlyFields(config string) string {
+	lines := strings.Split(config, "\n")
+	var filteredLines []string
+
+	// List of read-only fields that should not be included in IpcSet
+	readOnlyFields := map[string]bool{
+		"last_handshake_time_sec":  true,
+		"last_handshake_time_nsec": true,
+		"rx_bytes":                 true,
+		"tx_bytes":                 true,
+		"protocol_version":         true,
+	}
+
+	for _, line := range lines {
+		if line == "" {
+			continue
+		}
+
+		// Check if this line contains a read-only field
+		isReadOnly := false
+		for field := range readOnlyFields {
+			if strings.HasPrefix(line, field+"=") {
+				isReadOnly = true
+				break
+			}
+		}
+
+		// Only include non-read-only lines
+		if !isReadOnly {
+			filteredLines = append(filteredLines, line)
+		}
+	}
+
+	return strings.Join(filteredLines, "\n")
+}