remove context in struct

app/commander/commander.go

@@ -72,7 +72,7 @@ func (c *Commander) Start() error {
 	return nil
 }
 
-func (c *Commander) Close() {
+func (c *Commander) Close() error {
 	c.Lock()
 	defer c.Unlock()
 
@@ -80,6 +80,8 @@ func (c *Commander) Close() {
 		c.server.Stop()
 		c.server = nil
 	}
+
+	return nil
 }
 
 func init() {

app/commander/outbound.go

@@ -3,6 +3,7 @@ package commander
 import (
 	"context"
 	"net"
+	"sync"
 
 	"v2ray.com/core/common/signal"
 	"v2ray.com/core/transport/ray"
@@ -43,12 +44,24 @@ func (l *OutboundListener) Addr() net.Addr {
 type CommanderOutbound struct {
 	tag      string
 	listener *OutboundListener
+	access   sync.RWMutex
+	closed   bool
 }
 
 func (co *CommanderOutbound) Dispatch(ctx context.Context, r ray.OutboundRay) {
+	co.access.RLock()
+
+	if co.closed {
+		r.OutboundInput().CloseError()
+		r.OutboundOutput().CloseError()
+		co.access.RUnlock()
+		return
+	}
+
 	closeSignal := signal.NewNotifier()
 	c := ray.NewConnection(r.OutboundInput(), r.OutboundOutput(), ray.ConnCloseSignal(closeSignal))
 	co.listener.add(c)
+	co.access.RUnlock()
 	<-closeSignal.Wait()
 
 	return
@@ -59,7 +72,17 @@ func (co *CommanderOutbound) Tag() string {
 }
 
 func (co *CommanderOutbound) Start() error {
+	co.access.Lock()
+	co.closed = false
+	co.access.Unlock()
 	return nil
 }
 
-func (co *CommanderOutbound) Close() {}
+func (co *CommanderOutbound) Close() error {
+	co.access.Lock()
+	co.closed = true
+	co.listener.Close()
+	co.access.Unlock()
+
+	return nil
+}

app/dispatcher/default.go

@@ -49,7 +49,7 @@ func (*DefaultDispatcher) Start() error {
 }
 
 // Close implements app.Application.
-func (*DefaultDispatcher) Close() {}
+func (*DefaultDispatcher) Close() error { return nil }
 
 // Dispatch implements core.Dispatcher.
 func (d *DefaultDispatcher) Dispatch(ctx context.Context, destination net.Destination) (ray.InboundRay, error) {

app/dns/server.go

@@ -83,7 +83,8 @@ func (s *Server) Start() error {
 	return nil
 }
 
-func (*Server) Close() {
+func (*Server) Close() error {
+	return nil
 }
 
 func (s *Server) GetCached(domain string) []net.IP {

app/log/log.go

@@ -103,11 +103,13 @@ func (g *Instance) Handle(msg log.Message) {
 }
 
 // Close implement app.Application.Close().
-func (g *Instance) Close() {
+func (g *Instance) Close() error {
 	g.Lock()
 	defer g.Unlock()
 
 	g.active = false
+
+	return nil
 }
 
 func init() {

app/policy/manager.go

@@ -51,7 +51,8 @@ func (m *Instance) Start() error {
 }
 
 // Close implements app.Application.Close().
-func (m *Instance) Close() {
+func (m *Instance) Close() error {
+	return nil
 }
 
 func init() {

app/proxyman/command/command.go

@@ -119,7 +119,9 @@ func (*feature) Start() error {
 	return nil
 }
 
-func (*feature) Close() {}
+func (*feature) Close() error {
+	return nil
+}
 
 func init() {
 	common.Must(common.RegisterConfig((*Config)(nil), func(ctx context.Context, cfg interface{}) (interface{}, error) {

app/proxyman/inbound/always.go

@@ -76,10 +76,11 @@ func (h *AlwaysOnInboundHandler) Start() error {
 	return nil
 }
 
-func (h *AlwaysOnInboundHandler) Close() {
+func (h *AlwaysOnInboundHandler) Close() error {
 	for _, worker := range h.workers {
 		worker.Close()
 	}
+	return nil
 }
 
 func (h *AlwaysOnInboundHandler) GetRandomInboundProxy() (interface{}, net.Port, int) {

app/proxyman/inbound/dynamic.go

@@ -5,17 +5,18 @@ import (
 	"sync"
 	"time"
 
+	"v2ray.com/core"
 	"v2ray.com/core/app/proxyman"
 	"v2ray.com/core/app/proxyman/mux"
 	"v2ray.com/core/common/dice"
 	"v2ray.com/core/common/net"
+	"v2ray.com/core/common/signal"
 	"v2ray.com/core/proxy"
 )
 
 type DynamicInboundHandler struct {
 	tag            string
-	ctx            context.Context
-	cancel         context.CancelFunc
+	v              *core.Instance
 	proxyConfig    interface{}
 	receiverConfig *proxyman.ReceiverConfig
 	portMutex      sync.Mutex
@@ -24,18 +25,26 @@ type DynamicInboundHandler struct {
 	worker         []worker
 	lastRefresh    time.Time
 	mux            *mux.Server
+	task           *signal.PeriodicTask
 }
 
 func NewDynamicInboundHandler(ctx context.Context, tag string, receiverConfig *proxyman.ReceiverConfig, proxyConfig interface{}) (*DynamicInboundHandler, error) {
-	ctx, cancel := context.WithCancel(ctx)
+	v := core.FromContext(ctx)
+	if v == nil {
+		return nil, newError("V is not in context.")
+	}
 	h := &DynamicInboundHandler{
-		ctx:            ctx,
 		tag:            tag,
-		cancel:         cancel,
 		proxyConfig:    proxyConfig,
 		receiverConfig: receiverConfig,
 		portsInUse:     make(map[net.Port]bool),
 		mux:            mux.NewServer(ctx),
+		v:              v,
+	}
+
+	h.task = &signal.PeriodicTask{
+		Interval: time.Minute * time.Duration(h.receiverConfig.AllocationStrategy.GetRefreshValue()),
+		Execute:  h.refresh,
 	}
 
 	return h, nil
@@ -59,9 +68,7 @@ func (h *DynamicInboundHandler) allocatePort() net.Port {
 	}
 }
 
-func (h *DynamicInboundHandler) waitAnyCloseWorkers(ctx context.Context, cancel context.CancelFunc, workers []worker, duration time.Duration) {
-	time.Sleep(duration)
-	cancel()
+func (h *DynamicInboundHandler) closeWorkers(workers []worker) {
 	ports2Del := make([]net.Port, len(workers))
 	for idx, worker := range workers {
 		ports2Del[idx] = worker.Port()
@@ -80,7 +87,6 @@ func (h *DynamicInboundHandler) refresh() error {
 
 	timeout := time.Minute * time.Duration(h.receiverConfig.AllocationStrategy.GetRefreshValue()) * 2
 	concurrency := h.receiverConfig.AllocationStrategy.GetConcurrencyValue()
-	ctx, cancel := context.WithTimeout(h.ctx, timeout)
 	workers := make([]worker, 0, concurrency)
 
 	address := h.receiverConfig.Listen.AsAddress()
@@ -89,11 +95,12 @@ func (h *DynamicInboundHandler) refresh() error {
 	}
 	for i := uint32(0); i < concurrency; i++ {
 		port := h.allocatePort()
-		p, err := proxy.CreateInboundHandler(ctx, h.proxyConfig)
+		rawProxy, err := h.v.CreateObject(h.proxyConfig)
 		if err != nil {
 			newError("failed to create proxy instance").Base(err).AtWarning().WriteToLog()
 			continue
 		}
+		p := rawProxy.(proxy.Inbound)
 		nl := p.Network()
 		if nl.HasNetwork(net.Network_TCP) {
 			worker := &tcpWorker{
@@ -134,33 +141,19 @@ func (h *DynamicInboundHandler) refresh() error {
 	h.worker = workers
 	h.workerMutex.Unlock()
 
-	go h.waitAnyCloseWorkers(ctx, cancel, workers, timeout)
+	time.AfterFunc(timeout, func() {
+		h.closeWorkers(workers)
+	})
 
 	return nil
 }
 
-func (h *DynamicInboundHandler) monitor() {
-	timer := time.NewTicker(time.Minute * time.Duration(h.receiverConfig.AllocationStrategy.GetRefreshValue()))
-	defer timer.Stop()
-
-	for {
-		select {
-		case <-h.ctx.Done():
-			return
-		case <-timer.C:
-			h.refresh()
-		}
-	}
-}
-
 func (h *DynamicInboundHandler) Start() error {
-	err := h.refresh()
-	go h.monitor()
-	return err
+	return h.task.Start()
 }
 
-func (h *DynamicInboundHandler) Close() {
-	h.cancel()
+func (h *DynamicInboundHandler) Close() error {
+	return h.task.Close()
 }
 
 func (h *DynamicInboundHandler) GetRandomInboundProxy() (interface{}, net.Port, int) {

app/proxyman/inbound/inbound.go

@@ -99,7 +99,7 @@ func (m *Manager) Start() error {
 	return nil
 }
 
-func (m *Manager) Close() {
+func (m *Manager) Close() error {
 	m.access.Lock()
 	defer m.access.Unlock()
 
@@ -111,6 +111,8 @@ func (m *Manager) Close() {
 	for _, handler := range m.untaggedHandler {
 		handler.Close()
 	}
+
+	return nil
 }
 
 func NewHandler(ctx context.Context, config *core.InboundHandlerConfig) (core.InboundHandler, error) {

app/proxyman/inbound/worker.go

@@ -9,8 +9,10 @@ import (
 
 	"v2ray.com/core"
 	"v2ray.com/core/app/proxyman"
+	"v2ray.com/core/common"
 	"v2ray.com/core/common/buf"
 	"v2ray.com/core/common/net"
+	"v2ray.com/core/common/signal"
 	"v2ray.com/core/proxy"
 	"v2ray.com/core/transport/internet"
 	"v2ray.com/core/transport/internet/tcp"
@@ -19,7 +21,7 @@ import (
 
 type worker interface {
 	Start() error
-	Close()
+	Close() error
 	Port() net.Port
 	Proxy() proxy.Inbound
 }
@@ -34,13 +36,11 @@ type tcpWorker struct {
 	dispatcher   core.Dispatcher
 	sniffers     []proxyman.KnownProtocols
 
-	ctx    context.Context
-	cancel context.CancelFunc
-	hub    internet.Listener
+	hub internet.Listener
 }
 
 func (w *tcpWorker) callback(conn internet.Connection) {
-	ctx, cancel := context.WithCancel(w.ctx)
+	ctx, cancel := context.WithCancel(context.Background())
 	if w.recvOrigDest {
 		dest, err := tcp.GetOriginalDestination(conn)
 		if err != nil {
@@ -70,45 +70,24 @@ func (w *tcpWorker) Proxy() proxy.Inbound {
 }
 
 func (w *tcpWorker) Start() error {
-	ctx, cancel := context.WithCancel(context.Background())
-	w.ctx = ctx
-	w.cancel = cancel
-	ctx = internet.ContextWithStreamSettings(ctx, w.stream)
-	conns := make(chan internet.Connection, 16)
-	hub, err := internet.ListenTCP(ctx, w.address, w.port, conns)
+	ctx := internet.ContextWithStreamSettings(context.Background(), w.stream)
+	hub, err := internet.ListenTCP(ctx, w.address, w.port, func(conn internet.Connection) {
+		go w.callback(conn)
+	})
 	if err != nil {
 		return newError("failed to listen TCP on ", w.port).AtWarning().Base(err)
 	}
-	go w.handleConnections(conns)
 	w.hub = hub
 	return nil
 }
 
-func (w *tcpWorker) handleConnections(conns <-chan internet.Connection) {
-	for {
-		select {
-		case <-w.ctx.Done():
-			w.hub.Close()
-		L:
-			for {
-				select {
-				case conn := <-conns:
-					conn.Close()
-				default:
-					break L
-				}
-			}
-			return
-		case conn := <-conns:
-			go w.callback(conn)
-		}
-	}
-}
-
-func (w *tcpWorker) Close() {
+func (w *tcpWorker) Close() error {
 	if w.hub != nil {
-		w.cancel()
+		common.Close(w.hub)
+		common.Close(w.proxy)
 	}
+
+	return nil
 }
 
 func (w *tcpWorker) Port() net.Port {
@@ -121,8 +100,7 @@ type udpConn struct {
 	output           func([]byte) (int, error)
 	remote           net.Addr
 	local            net.Addr
-	ctx              context.Context
-	cancel           context.CancelFunc
+	done             *signal.Done
 }
 
 func (c *udpConn) updateActivity() {
@@ -135,7 +113,7 @@ func (c *udpConn) Read(buf []byte) (int, error) {
 		defer in.Release()
 		c.updateActivity()
 		return copy(buf, in.Bytes()), nil
-	case <-c.ctx.Done():
+	case <-c.done.C():
 		return 0, io.EOF
 	}
 }
@@ -150,6 +128,7 @@ func (c *udpConn) Write(buf []byte) (int, error) {
 }
 
 func (c *udpConn) Close() error {
+	common.Close(c.done)
 	return nil
 }
 
@@ -189,8 +168,7 @@ type udpWorker struct {
 	tag          string
 	dispatcher   core.Dispatcher
 
-	ctx        context.Context
-	cancel     context.CancelFunc
+	done       *signal.Done
 	activeConn map[connId]*udpConn
 }
 
@@ -215,6 +193,7 @@ func (w *udpWorker) getConnection(id connId) (*udpConn, bool) {
 			IP:   w.address.IP(),
 			Port: int(w.port),
 		},
+		done: signal.NewDone(),
 	}
 	w.activeConn[id] = conn
 
@@ -230,16 +209,15 @@ func (w *udpWorker) callback(b *buf.Buffer, source net.Destination, originalDest
 	conn, existing := w.getConnection(id)
 	select {
 	case conn.input <- b:
+	case <-conn.done.C():
+		b.Release()
 	default:
 		b.Release()
 	}
 
 	if !existing {
 		go func() {
-			ctx := w.ctx
-			ctx, cancel := context.WithCancel(ctx)
-			conn.ctx = ctx
-			conn.cancel = cancel
+			ctx := context.Background()
 			if originalDest.IsValid() {
 				ctx = proxy.ContextWithOriginalTarget(ctx, originalDest)
 			}
@@ -251,8 +229,8 @@ func (w *udpWorker) callback(b *buf.Buffer, source net.Destination, originalDest
 			if err := w.proxy.Process(ctx, net.Network_UDP, conn, w.dispatcher); err != nil {
 				newError("connection ends").Base(err).WriteToLog()
 			}
+			conn.Close()
 			w.removeConn(id)
-			cancel()
 		}()
 	}
 }
@@ -265,9 +243,7 @@ func (w *udpWorker) removeConn(id connId) {
 
 func (w *udpWorker) Start() error {
 	w.activeConn = make(map[connId]*udpConn, 16)
-	ctx, cancel := context.WithCancel(context.Background())
-	w.ctx = ctx
-	w.cancel = cancel
+	w.done = signal.NewDone()
 	h, err := udp.ListenUDP(w.address, w.port, udp.ListenOption{
 		Callback:            w.callback,
 		ReceiveOriginalDest: w.recvOrigDest,
@@ -280,11 +256,13 @@ func (w *udpWorker) Start() error {
 	return nil
 }
 
-func (w *udpWorker) Close() {
+func (w *udpWorker) Close() error {
 	if w.hub != nil {
 		w.hub.Close()
-		w.cancel()
+		w.done.Close()
+		common.Close(w.proxy)
 	}
+	return nil
 }
 
 func (w *udpWorker) monitor() {
@@ -293,7 +271,7 @@ func (w *udpWorker) monitor() {
 
 	for {
 		select {
-		case <-w.ctx.Done():
+		case <-w.done.C():
 			return
 		case <-timer.C:
 			nowSec := time.Now().Unix()
@@ -301,7 +279,7 @@ func (w *udpWorker) monitor() {
 			for addr, conn := range w.activeConn {
 				if nowSec-atomic.LoadInt64(&conn.lastActivityTime) > 8 {
 					delete(w.activeConn, addr)
-					conn.cancel()
+					conn.Close()
 				}
 			}
 			w.Unlock()

app/proxyman/mux/mux.go

@@ -291,7 +291,8 @@ func (s *Server) Start() error {
 	return nil
 }
 
-func (s *Server) Close() {
+func (s *Server) Close() error {
+	return nil
 }
 
 type ServerWorker struct {

app/proxyman/mux/session.go

@@ -103,12 +103,12 @@ func (m *SessionManager) CloseIfNoSession() bool {
 	return true
 }
 
-func (m *SessionManager) Close() {
+func (m *SessionManager) Close() error {
 	m.Lock()
 	defer m.Unlock()
 
 	if m.closed {
-		return
+		return nil
 	}
 
 	m.closed = true
@@ -119,6 +119,7 @@ func (m *SessionManager) Close() {
 	}
 
 	m.sessions = nil
+	return nil
 }
 
 // Session represents a client connection in a Mux connection.
@@ -131,10 +132,11 @@ type Session struct {
 }
 
 // Close closes all resources associated with this session.
-func (s *Session) Close() {
+func (s *Session) Close() error {
 	s.output.Close()
 	s.input.Close()
 	s.parent.Remove(s.ID)
+	return nil
 }
 
 // NewReader creates a buf.Reader based on the transfer type of this Session.

app/proxyman/mux/writer.go

@@ -100,7 +100,7 @@ func (w *Writer) WriteMultiBuffer(mb buf.MultiBuffer) error {
 	return nil
 }
 
-func (w *Writer) Close() {
+func (w *Writer) Close() error {
 	meta := FrameMetadata{
 		SessionID:     w.id,
 		SessionStatus: SessionStatusEnd,
@@ -110,4 +110,5 @@ func (w *Writer) Close() {
 	common.Must(frame.Reset(meta.AsSupplier()))
 
 	w.writer.WriteMultiBuffer(buf.NewMultiBufferValue(frame))
+	return nil
 }

app/proxyman/outbound/outbound.go

@@ -39,7 +39,7 @@ func New(ctx context.Context, config *proxyman.OutboundConfig) (*Manager, error)
 func (*Manager) Start() error { return nil }
 
 // Close implements core.Feature
-func (*Manager) Close() {}
+func (*Manager) Close() error { return nil }
 
 // GetDefaultHandler implements core.OutboundHandlerManager.
 func (m *Manager) GetDefaultHandler() core.OutboundHandler {

app/router/router.go

@@ -114,7 +114,9 @@ func (*Router) Start() error {
 	return nil
 }
 
-func (*Router) Close() {}
+func (*Router) Close() error {
+	return nil
+}
 
 func init() {
 	common.Must(common.RegisterConfig((*Config)(nil), func(ctx context.Context, config interface{}) (interface{}, error) {

clock.go

@@ -40,15 +40,15 @@ func (c *syncClock) Start() error {
 	return c.Clock.Start()
 }
 
-func (c *syncClock) Close() {
+func (c *syncClock) Close() error {
 	c.RLock()
 	defer c.RUnlock()
 
 	if c.Clock == nil {
-		return
+		return nil
 	}
 
-	c.Clock.Close()
+	return c.Clock.Close()
 }
 
 func (c *syncClock) Set(clock Clock) {

commander.go

@@ -44,15 +44,15 @@ func (c *syncCommander) Start() error {
 	return c.Commander.Start()
 }
 
-func (c *syncCommander) Close() {
+func (c *syncCommander) Close() error {
 	c.RLock()
 	defer c.RUnlock()
 
 	if c.Commander == nil {
-		return
+		return nil
 	}
 
-	c.Commander.Close()
+	return c.Commander.Close()
 }
 
 func (c *syncCommander) Set(commander Commander) {

common/interfaces.go

@@ -1,10 +1,23 @@
 package common
 
+// Closable is the interface for objects that can release its resources.
+type Closable interface {
+	// Close release all resources used by this object, including goroutines.
+	Close() error
+}
+
+// Close closes the obj if it is a Closable.
+func Close(obj interface{}) error {
+	if c, ok := obj.(Closable); ok {
+		return c.Close()
+	}
+	return nil
+}
+
 // Runnable is the interface for objects that can start to work and stop on demand.
 type Runnable interface {
 	// Start starts the runnable object. Upon the method returning nil, the object begins to function properly.
 	Start() error
 
-	// Close stops the object being working.
-	Close()
+	Closable
 }

common/signal/done.go

@@ -0,0 +1,48 @@
+package signal
+
+import (
+	"sync"
+)
+
+type Done struct {
+	access sync.Mutex
+	c      chan struct{}
+	closed bool
+}
+
+func NewDone() *Done {
+	return &Done{
+		c: make(chan struct{}),
+	}
+}
+
+func (d *Done) Done() bool {
+	select {
+	case <-d.c:
+		return true
+	default:
+		return false
+	}
+}
+
+func (d *Done) C() chan struct{} {
+	return d.c
+}
+
+func (d *Done) Wait() {
+	<-d.c
+}
+
+func (d *Done) Close() error {
+	d.access.Lock()
+	defer d.access.Unlock()
+
+	if d.closed {
+		return nil
+	}
+
+	d.closed = true
+	close(d.c)
+
+	return nil
+}

common/signal/notifier.go

@@ -1,22 +1,22 @@
 package signal
 
 type Notifier struct {
-	c chan bool
+	c chan struct{}
 }
 
 func NewNotifier() *Notifier {
 	return &Notifier{
-		c: make(chan bool, 1),
+		c: make(chan struct{}, 1),
 	}
 }
 
 func (n *Notifier) Signal() {
 	select {
-	case n.c <- true:
+	case n.c <- struct{}{}:
 	default:
 	}
 }
 
-func (n *Notifier) Wait() <-chan bool {
+func (n *Notifier) Wait() <-chan struct{} {
 	return n.c
 }

common/signal/semaphore.go

@@ -1,23 +1,23 @@
 package signal
 
 type Semaphore struct {
-	token chan bool
+	token chan struct{}
 }
 
 func NewSemaphore(n int) *Semaphore {
 	s := &Semaphore{
-		token: make(chan bool, n),
+		token: make(chan struct{}, n),
 	}
 	for i := 0; i < n; i++ {
-		s.token <- true
+		s.token <- struct{}{}
 	}
 	return s
 }
 
-func (s *Semaphore) Wait() <-chan bool {
+func (s *Semaphore) Wait() <-chan struct{} {
 	return s.token
 }
 
 func (s *Semaphore) Signal() {
-	s.token <- true
+	s.token <- struct{}{}
 }

common/signal/task.go

@@ -0,0 +1,60 @@
+package signal
+
+import (
+	"sync"
+	"time"
+)
+
+type PeriodicTask struct {
+	Interval time.Duration
+	Execute  func() error
+
+	access sync.Mutex
+	timer  *time.Timer
+	closed bool
+}
+
+func (t *PeriodicTask) checkedExecute() error {
+	t.access.Lock()
+	defer t.access.Unlock()
+
+	if t.closed {
+		return nil
+	}
+
+	if err := t.Execute(); err != nil {
+		return err
+	}
+
+	t.timer = time.AfterFunc(t.Interval, func() {
+		t.checkedExecute()
+	})
+
+	return nil
+}
+
+func (t *PeriodicTask) Start() error {
+	t.access.Lock()
+	t.closed = false
+	t.access.Unlock()
+
+	if err := t.checkedExecute(); err != nil {
+		t.closed = true
+		return err
+	}
+
+	return nil
+}
+
+func (t *PeriodicTask) Close() error {
+	t.access.Lock()
+	defer t.access.Unlock()
+
+	t.closed = true
+	if t.timer != nil {
+		t.timer.Stop()
+		t.timer = nil
+	}
+
+	return nil
+}

common/signal/timer.go

@@ -10,14 +10,14 @@ type ActivityUpdater interface {
 }
 
 type ActivityTimer struct {
-	updated chan bool
+	updated chan struct{}
 	timeout chan time.Duration
-	closing chan bool
+	closing chan struct{}
 }
 
 func (t *ActivityTimer) Update() {
 	select {
-	case t.updated <- true:
+	case t.updated <- struct{}{}:
 	default:
 	}
 }
@@ -72,8 +72,8 @@ func (t *ActivityTimer) run(ctx context.Context, cancel context.CancelFunc) {
 func CancelAfterInactivity(ctx context.Context, cancel context.CancelFunc, timeout time.Duration) *ActivityTimer {
 	timer := &ActivityTimer{
 		timeout: make(chan time.Duration, 1),
-		updated: make(chan bool, 1),
-		closing: make(chan bool),
+		updated: make(chan struct{}, 1),
+		closing: make(chan struct{}),
 	}
 	timer.timeout <- timeout
 	go timer.run(ctx, cancel)

dns.go

@@ -1,7 +1,11 @@
 package core
 
-import "net"
-import "sync"
+import (
+	"net"
+	"sync"
+
+	"v2ray.com/core/common"
+)
 
 // DNSClient is a V2Ray feature for querying DNS information.
 type DNSClient interface {
@@ -36,13 +40,11 @@ func (d *syncDNSClient) Start() error {
 	return d.DNSClient.Start()
 }
 
-func (d *syncDNSClient) Close() {
+func (d *syncDNSClient) Close() error {
 	d.RLock()
 	defer d.RUnlock()
 
-	if d.DNSClient != nil {
-		d.DNSClient.Close()
-	}
+	return common.Close(d.DNSClient)
 }
 
 func (d *syncDNSClient) Set(client DNSClient) {

network.go

@@ -21,6 +21,7 @@ type InboundHandler interface {
 
 // OutboundHandler is the interface for handlers that process outbound connections.
 type OutboundHandler interface {
+	common.Runnable
 	Tag() string
 	Dispatch(ctx context.Context, outboundRay ray.OutboundRay)
 }
@@ -75,13 +76,11 @@ func (m *syncInboundHandlerManager) Start() error {
 	return m.InboundHandlerManager.Start()
 }
 
-func (m *syncInboundHandlerManager) Close() {
+func (m *syncInboundHandlerManager) Close() error {
 	m.RLock()
 	defer m.RUnlock()
 
-	if m.InboundHandlerManager != nil {
-		m.InboundHandlerManager.Close()
-	}
+	return common.Close(m.InboundHandlerManager)
 }
 
 func (m *syncInboundHandlerManager) Set(manager InboundHandlerManager) {
@@ -154,13 +153,11 @@ func (m *syncOutboundHandlerManager) Start() error {
 	return m.OutboundHandlerManager.Start()
 }
 
-func (m *syncOutboundHandlerManager) Close() {
+func (m *syncOutboundHandlerManager) Close() error {
 	m.RLock()
 	defer m.RUnlock()
 
-	if m.OutboundHandlerManager != nil {
-		m.OutboundHandlerManager.Close()
-	}
+	return common.Close(m.OutboundHandlerManager)
 }
 
 func (m *syncOutboundHandlerManager) Set(manager OutboundHandlerManager) {

policy.go

@@ -3,6 +3,8 @@ package core
 import (
 	"sync"
 	"time"
+
+	"v2ray.com/core/common"
 )
 
 // TimeoutPolicy contains limits for connection timeout.
@@ -96,13 +98,11 @@ func (m *syncPolicyManager) Start() error {
 	return m.PolicyManager.Start()
 }
 
-func (m *syncPolicyManager) Close() {
+func (m *syncPolicyManager) Close() error {
 	m.RLock()
 	defer m.RUnlock()
 
-	if m.PolicyManager != nil {
-		m.PolicyManager.Close()
-	}
+	return common.Close(m.PolicyManager)
 }
 
 func (m *syncPolicyManager) Set(manager PolicyManager) {

proxy/vmess/encoding/encoding_test.go

@@ -48,8 +48,9 @@ func TestRequestSerialization(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	sessionHistory := NewSessionHistory()
 
-	userValidator := vmess.NewTimedUserValidator(ctx, protocol.DefaultIDHash)
+	userValidator := vmess.NewTimedUserValidator(protocol.DefaultIDHash)
 	userValidator.Add(user)
+	defer common.Close(userValidator)
 
 	server := NewServerSession(userValidator, sessionHistory)
 	actualRequest, err := server.DecodeRequestHeader(buffer)

proxy/vmess/encoding/server.go

@@ -30,28 +30,34 @@ type sessionId struct {
 type SessionHistory struct {
 	sync.RWMutex
 	cache map[sessionId]time.Time
-	token *signal.Semaphore
-	timer *time.Timer
+	task  *signal.PeriodicTask
 }
 
 func NewSessionHistory() *SessionHistory {
 	h := &SessionHistory{
 		cache: make(map[sessionId]time.Time, 128),
-		token: signal.NewSemaphore(1),
 	}
+	h.task = &signal.PeriodicTask{
+		Interval: time.Second * 30,
+		Execute: func() error {
+			h.removeExpiredEntries()
+			return nil
+		},
+	}
+	common.Must(h.task.Start())
 	return h
 }
 
+// Close implements common.Closable.
+func (h *SessionHistory) Close() error {
+	return h.task.Close()
+}
+
 func (h *SessionHistory) add(session sessionId) {
 	h.Lock()
 	defer h.Unlock()
 
 	h.cache[session] = time.Now().Add(time.Minute * 3)
-	select {
-	case <-h.token.Wait():
-		h.timer = time.AfterFunc(time.Minute*3, h.removeExpiredEntries)
-	default:
-	}
 }
 
 func (h *SessionHistory) has(session sessionId) bool {
@@ -75,11 +81,6 @@ func (h *SessionHistory) removeExpiredEntries() {
 			delete(h.cache, session)
 		}
 	}
-
-	if h.timer != nil {
-		h.timer.Stop()
-		h.timer = nil
-	}
 }
 
 type ServerSession struct {

proxy/vmess/inbound/inbound.go

@@ -90,7 +90,7 @@ func New(ctx context.Context, config *Config) (*Handler, error) {
 	handler := &Handler{
 		policyManager:         v.PolicyManager(),
 		inboundHandlerManager: v.InboundHandlerManager(),
-		clients:               vmess.NewTimedUserValidator(ctx, protocol.DefaultIDHash),
+		clients:               vmess.NewTimedUserValidator(protocol.DefaultIDHash),
 		detours:               config.Detour,
 		usersByEmail:          newUserByEmail(config.User, config.GetDefaultValue()),
 		sessionHistory:        encoding.NewSessionHistory(),
@@ -105,6 +105,14 @@ func New(ctx context.Context, config *Config) (*Handler, error) {
 	return handler, nil
 }
 
+// Close implements common.Closable.
+func (h *Handler) Close() error {
+	common.Close(h.clients)
+	common.Close(h.sessionHistory)
+	common.Close(h.usersByEmail)
+	return nil
+}
+
 // Network implements proxy.Inbound.Network().
 func (*Handler) Network() net.NetworkList {
 	return net.NetworkList{

proxy/vmess/vmess.go

@@ -8,17 +8,17 @@ package vmess
 //go:generate go run $GOPATH/src/v2ray.com/core/common/errors/errorgen/main.go -pkg vmess -path Proxy,VMess
 
 import (
-	"context"
 	"sync"
 	"time"
 
 	"v2ray.com/core/common"
 	"v2ray.com/core/common/protocol"
+	"v2ray.com/core/common/signal"
 )
 
 const (
-	updateIntervalSec = 10
-	cacheDurationSec  = 120
+	updateInterval   = 10 * time.Second
+	cacheDurationSec = 120
 )
 
 type idEntry struct {
@@ -34,6 +34,7 @@ type TimedUserValidator struct {
 	ids        []*idEntry
 	hasher     protocol.IDHash
 	baseTime   protocol.Timestamp
+	task       *signal.PeriodicTask
 }
 
 type indexTimePair struct {
@@ -41,16 +42,23 @@ type indexTimePair struct {
 	timeInc uint32
 }
 
-func NewTimedUserValidator(ctx context.Context, hasher protocol.IDHash) protocol.UserValidator {
-	tus := &TimedUserValidator{
+func NewTimedUserValidator(hasher protocol.IDHash) protocol.UserValidator {
+	tuv := &TimedUserValidator{
 		validUsers: make([]*protocol.User, 0, 16),
 		userHash:   make(map[[16]byte]indexTimePair, 512),
 		ids:        make([]*idEntry, 0, 512),
 		hasher:     hasher,
 		baseTime:   protocol.Timestamp(time.Now().Unix() - cacheDurationSec*3),
 	}
-	go tus.updateUserHash(ctx, updateIntervalSec*time.Second)
-	return tus
+	tuv.task = &signal.PeriodicTask{
+		Interval: updateInterval,
+		Execute: func() error {
+			tuv.updateUserHash()
+			return nil
+		},
+	}
+	tuv.task.Start()
+	return tuv
 }
 
 func (v *TimedUserValidator) generateNewHashes(nowSec protocol.Timestamp, idx int, entry *idEntry) {
@@ -78,24 +86,19 @@ func (v *TimedUserValidator) removeExpiredHashes(expire uint32) {
 	}
 }
 
-func (v *TimedUserValidator) updateUserHash(ctx context.Context, interval time.Duration) {
-	for {
-		select {
-		case now := <-time.After(interval):
-			nowSec := protocol.Timestamp(now.Unix() + cacheDurationSec)
-			v.Lock()
-			for _, entry := range v.ids {
-				v.generateNewHashes(nowSec, entry.userIdx, entry)
-			}
-
-			expire := protocol.Timestamp(now.Unix() - cacheDurationSec*3)
-			if expire > v.baseTime {
-				v.removeExpiredHashes(uint32(expire - v.baseTime))
-			}
-			v.Unlock()
-		case <-ctx.Done():
-			return
-		}
+func (v *TimedUserValidator) updateUserHash() {
+	now := time.Now()
+	nowSec := protocol.Timestamp(now.Unix() + cacheDurationSec)
+	v.Lock()
+	defer v.Unlock()
+
+	for _, entry := range v.ids {
+		v.generateNewHashes(nowSec, entry.userIdx, entry)
+	}
+
+	expire := protocol.Timestamp(now.Unix() - cacheDurationSec*3)
+	if expire > v.baseTime {
+		v.removeExpiredHashes(uint32(expire - v.baseTime))
 	}
 }
 
@@ -145,3 +148,8 @@ func (v *TimedUserValidator) Get(userHash []byte) (*protocol.User, protocol.Time
 	}
 	return nil, 0, false
 }
+
+// Close implements common.Closable.
+func (v *TimedUserValidator) Close() error {
+	return v.task.Close()
+}

router.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"sync"
 
+	"v2ray.com/core/common"
 	"v2ray.com/core/common/errors"
 	"v2ray.com/core/common/net"
 	"v2ray.com/core/transport/ray"
@@ -45,13 +46,11 @@ func (d *syncDispatcher) Start() error {
 	return d.Dispatcher.Start()
 }
 
-func (d *syncDispatcher) Close() {
+func (d *syncDispatcher) Close() error {
 	d.RLock()
 	defer d.RUnlock()
 
-	if d.Dispatcher != nil {
-		d.Dispatcher.Close()
-	}
+	return common.Close(d.Dispatcher)
 }
 
 func (d *syncDispatcher) Set(disp Dispatcher) {
@@ -101,13 +100,11 @@ func (r *syncRouter) Start() error {
 	return r.Router.Start()
 }
 
-func (r *syncRouter) Close() {
+func (r *syncRouter) Close() error {
 	r.RLock()
 	defer r.RUnlock()
 
-	if r.Router != nil {
-		r.Router.Close()
-	}
+	return common.Close(r.Router)
 }
 
 func (r *syncRouter) Set(router Router) {

testing/servers/http/http.go

@@ -36,6 +36,6 @@ func (s *Server) Start() (net.Destination, error) {
 	return net.TCPDestination(net.LocalHostIP, net.Port(s.Port)), nil
 }
 
-func (s *Server) Close() {
-	s.server.Close()
+func (s *Server) Close() error {
+	return s.server.Close()
 }

testing/servers/tcp/tcp.go

@@ -69,6 +69,6 @@ func (server *Server) handleConnection(conn net.Conn) {
 	conn.Close()
 }
 
-func (server *Server) Close() {
-	server.listener.Close()
+func (server *Server) Close() error {
+	return server.listener.Close()
 }

testing/servers/udp/udp.go

@@ -46,7 +46,7 @@ func (server *Server) handleConnection(conn *net.UDPConn) {
 	}
 }
 
-func (server *Server) Close() {
+func (server *Server) Close() error {
 	server.accepting = false
-	server.conn.Close()
+	return server.conn.Close()
 }

transport/internet/kcp/listener.go

@@ -23,7 +23,6 @@ type ConnectionID struct {
 // Listener defines a server listening for connections
 type Listener struct {
 	sync.Mutex
-	ctx       context.Context
 	sessions  map[ConnectionID]*Connection
 	hub       *udp.Hub
 	tlsConfig *tls.Config
@@ -31,10 +30,10 @@ type Listener struct {
 	reader    PacketReader
 	header    internet.PacketHeader
 	security  cipher.AEAD
-	addConn   internet.AddConnection
+	addConn   internet.ConnHandler
 }
 
-func NewListener(ctx context.Context, address net.Address, port net.Port, addConn internet.AddConnection) (*Listener, error) {
+func NewListener(ctx context.Context, address net.Address, port net.Port, addConn internet.ConnHandler) (*Listener, error) {
 	networkSettings := internet.TransportSettingsFromContext(ctx)
 	kcpSettings := networkSettings.(*Config)
 
@@ -54,7 +53,6 @@ func NewListener(ctx context.Context, address net.Address, port net.Port, addCon
 			Security: security,
 		},
 		sessions: make(map[ConnectionID]*Connection),
-		ctx:      ctx,
 		config:   kcpSettings,
 		addConn:  addConn,
 	}
@@ -86,12 +84,6 @@ func (l *Listener) OnReceive(payload *buf.Buffer, src net.Destination, originalD
 	l.Lock()
 	defer l.Unlock()
 
-	select {
-	case <-l.ctx.Done():
-		return
-	default:
-	}
-
 	if l.hub == nil {
 		return
 	}
@@ -136,23 +128,16 @@ func (l *Listener) OnReceive(payload *buf.Buffer, src net.Destination, originalD
 			netConn = tlsConn
 		}
 
-		if !l.addConn(context.Background(), netConn) {
-			return
-		}
+		l.addConn(netConn)
 		l.sessions[id] = conn
 	}
 	conn.Input(segments)
 }
 
 func (l *Listener) Remove(id ConnectionID) {
-	select {
-	case <-l.ctx.Done():
-		return
-	default:
-		l.Lock()
-		delete(l.sessions, id)
-		l.Unlock()
-	}
+	l.Lock()
+	delete(l.sessions, id)
+	l.Unlock()
 }
 
 // Close stops listening on the UDP address. Already Accepted connections are not closed.
@@ -197,7 +182,7 @@ func (w *Writer) Close() error {
 	return nil
 }
 
-func ListenKCP(ctx context.Context, address net.Address, port net.Port, addConn internet.AddConnection) (internet.Listener, error) {
+func ListenKCP(ctx context.Context, address net.Address, port net.Port, addConn internet.ConnHandler) (internet.Listener, error) {
 	return NewListener(ctx, address, port, addConn)
 }
 

transport/internet/tcp/hub.go

@@ -3,10 +3,10 @@ package tcp
 import (
 	"context"
 	gotls "crypto/tls"
+	"strings"
 
 	"v2ray.com/core/common"
 	"v2ray.com/core/common/net"
-	"v2ray.com/core/common/retry"
 	"v2ray.com/core/transport/internet"
 	"v2ray.com/core/transport/internet/tls"
 )
@@ -17,11 +17,11 @@ type Listener struct {
 	tlsConfig  *gotls.Config
 	authConfig internet.ConnectionAuthenticator
 	config     *Config
-	addConn    internet.AddConnection
+	addConn    internet.ConnHandler
 }
 
 // ListenTCP creates a new Listener based on configurations.
-func ListenTCP(ctx context.Context, address net.Address, port net.Port, addConn internet.AddConnection) (internet.Listener, error) {
+func ListenTCP(ctx context.Context, address net.Address, port net.Port, handler internet.ConnHandler) (internet.Listener, error) {
 	listener, err := net.ListenTCP("tcp", &net.TCPAddr{
 		IP:   address.IP(),
 		Port: int(port),
@@ -36,7 +36,7 @@ func ListenTCP(ctx context.Context, address net.Address, port net.Port, addConn
 	l := &Listener{
 		listener: listener,
 		config:   tcpSettings,
-		addConn:  addConn,
+		addConn:  handler,
 	}
 
 	if config := tls.ConfigFromContext(ctx, tls.WithNextProto("h2")); config != nil {
@@ -54,27 +54,17 @@ func ListenTCP(ctx context.Context, address net.Address, port net.Port, addConn
 		}
 		l.authConfig = auth
 	}
-	go l.keepAccepting(ctx)
+	go l.keepAccepting()
 	return l, nil
 }
 
-func (v *Listener) keepAccepting(ctx context.Context) {
+func (v *Listener) keepAccepting() {
 	for {
-		select {
-		case <-ctx.Done():
-			return
-		default:
-		}
-		var conn net.Conn
-		err := retry.ExponentialBackoff(5, 200).On(func() error {
-			rawConn, err := v.listener.Accept()
-			if err != nil {
-				return err
-			}
-			conn = rawConn
-			return nil
-		})
+		conn, err := v.listener.Accept()
 		if err != nil {
+			if strings.Contains(err.Error(), "closed") {
+				break
+			}
 			newError("failed to accepted raw connections").Base(err).AtWarning().WriteToLog()
 			continue
 		}
@@ -86,7 +76,7 @@ func (v *Listener) keepAccepting(ctx context.Context) {
 			conn = v.authConfig.Server(conn)
 		}
 
-		v.addConn(context.Background(), internet.Connection(conn))
+		v.addConn(internet.Connection(conn))
 	}
 }
 

transport/internet/tcp_hub.go

@@ -2,7 +2,6 @@ package internet
 
 import (
 	"context"
-	"time"
 
 	"v2ray.com/core/common/net"
 )
@@ -19,16 +18,16 @@ func RegisterTransportListener(protocol TransportProtocol, listener ListenFunc)
 	return nil
 }
 
-type AddConnection func(context.Context, Connection) bool
+type ConnHandler func(Connection)
 
-type ListenFunc func(ctx context.Context, address net.Address, port net.Port, addConn AddConnection) (Listener, error)
+type ListenFunc func(ctx context.Context, address net.Address, port net.Port, handler ConnHandler) (Listener, error)
 
 type Listener interface {
 	Close() error
 	Addr() net.Addr
 }
 
-func ListenTCP(ctx context.Context, address net.Address, port net.Port, conns chan<- Connection) (Listener, error) {
+func ListenTCP(ctx context.Context, address net.Address, port net.Port, handler ConnHandler) (Listener, error) {
 	settings := StreamSettingsFromContext(ctx)
 	protocol := settings.GetEffectiveProtocol()
 	transportSettings, err := settings.GetEffectiveTransportSettings()
@@ -47,26 +46,7 @@ func ListenTCP(ctx context.Context, address net.Address, port net.Port, conns ch
 	if listenFunc == nil {
 		return nil, newError(protocol, " listener not registered.").AtError()
 	}
-	listener, err := listenFunc(ctx, address, port, func(ctx context.Context, conn Connection) bool {
-		select {
-		case <-ctx.Done():
-			conn.Close()
-			return false
-		case conns <- conn:
-			return true
-		default:
-			select {
-			case <-ctx.Done():
-				conn.Close()
-				return false
-			case conns <- conn:
-				return true
-			case <-time.After(time.Second * 5):
-				conn.Close()
-				return false
-			}
-		}
-	})
+	listener, err := listenFunc(ctx, address, port, handler)
 	if err != nil {
 		return nil, newError("failed to listen on address: ", address, ":", port).Base(err)
 	}

transport/internet/udp/dispatcher_test.go

@@ -25,7 +25,9 @@ func (d *TestDispatcher) Start() error {
 	return nil
 }
 
-func (d *TestDispatcher) Close() {}
+func (d *TestDispatcher) Close() error {
+	return nil
+}
 
 func TestSameDestinationDispatching(t *testing.T) {
 	assert := With(t)

transport/internet/udp/hub.go

@@ -60,10 +60,11 @@ func (q *PayloadQueue) Dequeue(queue <-chan Payload) {
 	}
 }
 
-func (q *PayloadQueue) Close() {
+func (q *PayloadQueue) Close() error {
 	for _, queue := range q.queue {
 		close(queue)
 	}
+	return nil
 }
 
 type ListenOption struct {
@@ -116,9 +117,10 @@ func ListenUDP(address net.Address, port net.Port, option ListenOption) (*Hub, e
 	return hub, nil
 }
 
-func (h *Hub) Close() {
+func (h *Hub) Close() error {
 	h.cancel()
 	h.conn.Close()
+	return nil
 }
 
 func (h *Hub) WriteTo(payload []byte, dest net.Destination) (int, error) {

transport/internet/websocket/hub.go

@@ -44,24 +44,22 @@ func (h *requestHandler) ServeHTTP(writer http.ResponseWriter, request *http.Req
 		remoteAddr.(*net.TCPAddr).IP = forwardedAddrs[0].IP()
 	}
 
-	h.ln.addConn(h.ln.ctx, newConnection(conn, remoteAddr))
+	h.ln.addConn(newConnection(conn, remoteAddr))
 }
 
 type Listener struct {
 	sync.Mutex
-	ctx       context.Context
 	listener  net.Listener
 	tlsConfig *tls.Config
 	config    *Config
-	addConn   internet.AddConnection
+	addConn   internet.ConnHandler
 }
 
-func ListenWS(ctx context.Context, address net.Address, port net.Port, addConn internet.AddConnection) (internet.Listener, error) {
+func ListenWS(ctx context.Context, address net.Address, port net.Port, addConn internet.ConnHandler) (internet.Listener, error) {
 	networkSettings := internet.TransportSettingsFromContext(ctx)
 	wsSettings := networkSettings.(*Config)
 
 	l := &Listener{
-		ctx:     ctx,
 		config:  wsSettings,
 		addConn: addConn,
 	}

transport/ray/direct.go

@@ -209,12 +209,13 @@ func (s *Stream) WriteMultiBuffer(data buf.MultiBuffer) error {
 }
 
 // Close closes the stream for writing. Read() still works until EOF.
-func (s *Stream) Close() {
+func (s *Stream) Close() error {
 	s.access.Lock()
 	s.close = true
 	s.readSignal.Signal()
 	s.writeSignal.Signal()
 	s.access.Unlock()
+	return nil
 }
 
 // CloseError closes the Stream with error. Read() will return an error afterwards.

transport/ray/ray.go

@@ -1,6 +1,9 @@
 package ray
 
-import "v2ray.com/core/common/buf"
+import (
+	"v2ray.com/core/common"
+	"v2ray.com/core/common/buf"
+)
 
 // OutboundRay is a transport interface for outbound connections.
 type OutboundRay interface {
@@ -34,7 +37,7 @@ type Ray interface {
 }
 
 type RayStream interface {
-	Close()
+	common.Closable
 	CloseError()
 }
 

v2ray.go

@@ -101,7 +101,7 @@ func (s *Instance) ID() uuid.UUID {
 }
 
 // Close shutdown the V2Ray instance.
-func (s *Instance) Close() {
+func (s *Instance) Close() error {
 	s.access.Lock()
 	defer s.access.Unlock()
 
@@ -109,6 +109,8 @@ func (s *Instance) Close() {
 	for _, f := range s.features {
 		f.Close()
 	}
+
+	return nil
 }
 
 // Start starts the V2Ray instance, including all registered features. When Start returns error, the state of the instance is unknown.