app: improve graceful shutdown

application.go

@@ -226,6 +226,14 @@ func (a *Application) Close() {
 			a.logger.Errorf("closing api server: %v", err)
 		}
 	}
+
+	if a.Tunnel != nil {
+		a.Tunnel.Close()
+	}
+	if a.SOCKS5 != nil {
+		a.SOCKS5.Close()
+	}
+
 	if a.P2p != nil {
 		err := a.P2p.Close()
 		if err != nil {
@@ -235,12 +243,6 @@ func (a *Application) Close() {
 	if a.Dns != nil {
 		a.Dns.Close()
 	}
-	if a.Tunnel != nil {
-		a.Tunnel.Close()
-	}
-	if a.SOCKS5 != nil {
-		a.SOCKS5.Close()
-	}
 	if a.vpnDevice != nil {
 		err := a.vpnDevice.Close()
 		if err != nil {

vpn/vpn.go

@@ -32,6 +32,7 @@ type Device struct {
 	localIP    net.IP
 	outboundCh chan *Packet
 
+	closeCh     chan struct{}
 	packetsPool sync.Pool
 	logger      *log.ZapEventLogger
 }
@@ -62,7 +63,8 @@ func NewDevice(existingTun tun.Device, interfaceName string, localIP net.IP, ipM
 			New: func() interface{} {
 				return new(Packet)
 			}},
-		logger: log.Logger("awl/vpn"),
+		logger:  log.Logger("awl/vpn"),
+		closeCh: make(chan struct{}),
 	}
 	go dev.tunEventsReader()
 	go dev.tunPacketsReader()
@@ -106,6 +108,7 @@ func (d *Device) OutboundChan() <-chan *Packet {
 }
 
 func (d *Device) Close() error {
+	close(d.closeCh)
 	return d.tun.Close()
 }
 
@@ -173,7 +176,12 @@ func (d *Device) tunPacketsReader() {
 				continue
 			}
 
-			d.outboundCh <- data
+			select {
+			case <-d.closeCh:
+				return
+			case d.outboundCh <- data:
+				// ok
+			}
 			packets[i] = nil
 		}