[client] Add bind activity listener to bypass udp sockets (#4646)

client/iface/device.go

@@ -23,4 +23,5 @@ type WGTunDevice interface {
 	FilteredDevice() *device.FilteredDevice
 	Device() *wgdevice.Device
 	GetNet() *netstack.Net
+	GetICEBind() device.EndpointManager
 }

client/iface/device/device_android.go

@@ -150,6 +150,11 @@ func (t *WGTunDevice) GetNet() *netstack.Net {
 	return nil
 }
 
+// GetICEBind returns the ICEBind instance
+func (t *WGTunDevice) GetICEBind() EndpointManager {
+	return t.iceBind
+}
+
 func routesToString(routes []string) string {
 	return strings.Join(routes, ";")
 }

client/iface/device/device_darwin.go

@@ -154,3 +154,8 @@ func (t *TunDevice) assignAddr() error {
 func (t *TunDevice) GetNet() *netstack.Net {
 	return nil
 }
+
+// GetICEBind returns the ICEBind instance
+func (t *TunDevice) GetICEBind() EndpointManager {
+	return t.iceBind
+}

client/iface/device/device_ios.go

@@ -144,3 +144,8 @@ func (t *TunDevice) FilteredDevice() *FilteredDevice {
 func (t *TunDevice) GetNet() *netstack.Net {
 	return nil
 }
+
+// GetICEBind returns the ICEBind instance
+func (t *TunDevice) GetICEBind() EndpointManager {
+	return t.iceBind
+}

client/iface/device/device_kernel_unix.go

@@ -179,3 +179,8 @@ func (t *TunKernelDevice) assignAddr() error {
 func (t *TunKernelDevice) GetNet() *netstack.Net {
 	return nil
 }
+
+// GetICEBind returns nil for kernel mode devices
+func (t *TunKernelDevice) GetICEBind() EndpointManager {
+	return nil
+}

client/iface/device/device_netstack.go

@@ -21,6 +21,7 @@ type Bind interface {
 	conn.Bind
 	GetICEMux() (*udpmux.UniversalUDPMuxDefault, error)
 	ActivityRecorder() *bind.ActivityRecorder
+	EndpointManager
 }
 
 type TunNetstackDevice struct {
@@ -155,3 +156,8 @@ func (t *TunNetstackDevice) Device() *device.Device {
 func (t *TunNetstackDevice) GetNet() *netstack.Net {
 	return t.net
 }
+
+// GetICEBind returns the bind instance
+func (t *TunNetstackDevice) GetICEBind() EndpointManager {
+	return t.bind
+}

client/iface/device/device_usp_unix.go

@@ -146,3 +146,8 @@ func (t *USPDevice) assignAddr() error {
 func (t *USPDevice) GetNet() *netstack.Net {
 	return nil
 }
+
+// GetICEBind returns the ICEBind instance
+func (t *USPDevice) GetICEBind() EndpointManager {
+	return t.iceBind
+}

client/iface/device/device_windows.go

@@ -185,3 +185,8 @@ func (t *TunDevice) assignAddr() error {
 func (t *TunDevice) GetNet() *netstack.Net {
 	return nil
 }
+
+// GetICEBind returns the ICEBind instance
+func (t *TunDevice) GetICEBind() EndpointManager {
+	return t.iceBind
+}

client/iface/device/endpoint_manager.go

@@ -0,0 +1,13 @@
+package device
+
+import (
+	"net"
+	"net/netip"
+)
+
+// EndpointManager manages fake IP to connection mappings for userspace bind implementations.
+// Implemented by bind.ICEBind and bind.RelayBindJS.
+type EndpointManager interface {
+	SetEndpoint(fakeIP netip.Addr, conn net.Conn)
+	RemoveEndpoint(fakeIP netip.Addr)
+}

client/iface/device_android.go

@@ -21,4 +21,5 @@ type WGTunDevice interface {
 	FilteredDevice() *device.FilteredDevice
 	Device() *wgdevice.Device
 	GetNet() *netstack.Net
+	GetICEBind() device.EndpointManager
 }

client/iface/iface.go

@@ -80,6 +80,17 @@ func (w *WGIface) GetProxy() wgproxy.Proxy {
 	return w.wgProxyFactory.GetProxy()
 }
 
+// GetBind returns the EndpointManager userspace bind mode.
+func (w *WGIface) GetBind() device.EndpointManager {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	if w.tun == nil {
+		return nil
+	}
+	return w.tun.GetICEBind()
+}
+
 // IsUserspaceBind indicates whether this interfaces is userspace with bind.ICEBind
 func (w *WGIface) IsUserspaceBind() bool {
 	return w.userspaceBind