ui: only allow a single tunnel to be active at any time

Signed-off-by: Alexander Neumann <alexander.neumann@picos-software.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

1 files changed, 99 insertions, 0 deletions

diff --git a/ui/tunneltracker.go b/ui/tunneltracker.go
new file mode 100644
index 00000000..73d48538
--- /dev/null
+++ b/ui/tunneltracker.go
@@ -0,0 +1,99 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package ui
+
+import (
+	"fmt"
+
+	"github.com/lxn/walk"
+	"golang.zx2c4.com/wireguard/windows/service"
+)
+
+type TunnelTracker struct {
+	activeTunnel        *service.Tunnel
+	activeTunnelChanged walk.EventPublisher
+	tunnelChangeCB      *service.TunnelChangeCallback
+	inTransition        bool
+}
+
+func (tt *TunnelTracker) ActiveTunnel() *service.Tunnel {
+	return tt.activeTunnel
+}
+
+func (tt *TunnelTracker) ActivateTunnel(tunnel *service.Tunnel) error {
+	if tunnel == tt.activeTunnel {
+		return nil
+	}
+
+	if err := tt.DeactivateTunnel(); err != nil {
+		return fmt.Errorf("ActivateTunnel: Failed to deactivate tunnel '%s': %v", tunnel.Name, err)
+	}
+
+	if err := tunnel.Start(); err != nil {
+		return fmt.Errorf("ActivateTunnel: Failed to start tunnel '%s': %v", tunnel.Name, err)
+	}
+
+	return nil
+}
+
+func (tt *TunnelTracker) DeactivateTunnel() error {
+	if tt.activeTunnel == nil {
+		return nil
+	}
+
+	state, err := tt.activeTunnel.State()
+	if err != nil {
+		return fmt.Errorf("DeactivateTunnel: Failed to retrieve state for tunnel %s: %v", tt.activeTunnel.Name, err)
+	}
+
+	if state == service.TunnelStarted {
+		if err := tt.activeTunnel.Stop(); err != nil {
+			return fmt.Errorf("DeactivateTunnel: Failed to stop tunnel '%s': %v", tt.activeTunnel.Name, err)
+		}
+	}
+
+	if state == service.TunnelStarted || state == service.TunnelStopping {
+		if err := tt.activeTunnel.WaitForStop(); err != nil {
+			return fmt.Errorf("DeactivateTunnel: Failed to wait for tunnel '%s' to stop: %v", tt.activeTunnel.Name, err)
+		}
+	}
+
+	return nil
+}
+
+func (tt *TunnelTracker) ActiveTunnelChanged() *walk.Event {
+	return tt.activeTunnelChanged.Event()
+}
+
+func (tt *TunnelTracker) InTransition() bool {
+	return tt.inTransition
+}
+
+func (tt *TunnelTracker) SetTunnelState(tunnel *service.Tunnel, state service.TunnelState, err error) {
+	if err != nil {
+		tt.inTransition = false
+	}
+
+	switch state {
+	case service.TunnelStarted:
+		tt.inTransition = false
+		tt.activeTunnel = tunnel
+
+	case service.TunnelStarting, service.TunnelStopping:
+		tt.inTransition = true
+
+	case service.TunnelStopped:
+		if tt.activeTunnel != nil && tt.activeTunnel.Name == tunnel.Name {
+			tt.inTransition = false
+		}
+		tt.activeTunnel = nil
+
+	default:
+		return
+	}
+
+	tt.activeTunnelChanged.Publish()
+}