chore: anytls protocol version 2 (#1936)

listener/anytls/server.go

@@ -174,6 +174,12 @@ func (l *Listener) HandleConn(conn net.Conn, h *sing.ListenerHandler) {
 			return
 		}
 
+		// It seems that mihomo does not implement a connection error reporting mechanism, so we report success directly.
+		err = stream.HandshakeSuccess()
+		if err != nil {
+			return
+		}
+
 		h.NewConnection(ctx, stream, M.Metadata{
 			Source:      M.SocksaddrFromNet(conn.RemoteAddr()),
 			Destination: destination,

transport/anytls/padding/padding.go

@@ -15,10 +15,10 @@ import (
 const CheckMark = -1
 
 var DefaultPaddingScheme = []byte(`stop=8
-0=34-120
+0=30-30
 1=100-400
-2=400-500,c,500-1000,c,400-500,c,500-1000,c,500-1000,c,400-500
-3=500-1000
+2=400-500,c,500-1000,c,500-1000,c,500-1000,c,500-1000
+3=9-9,500-1000
 4=500-1000
 5=500-1000
 6=500-1000

transport/anytls/session/client.go

@@ -83,11 +83,7 @@ func (c *Client) CreateStream(ctx context.Context) (net.Conn, error) {
 	}
 
 	stream.dieHook = func() {
-		if session.IsClosed() {
-			if session.dieHook != nil {
-				session.dieHook()
-			}
-		} else {
+		if !session.IsClosed() {
 			select {
 			case <-c.die.Done():
 				// Now client has been closed
@@ -154,10 +150,10 @@ func (c *Client) Close() error {
 
 	c.sessionsLock.Lock()
 	sessionToClose := make([]*Session, 0, len(c.sessions))
-	for seq, session := range c.sessions {
+	for _, session := range c.sessions {
 		sessionToClose = append(sessionToClose, session)
-		delete(c.sessions, seq)
 	}
+	c.sessions = make(map[uint64]*Session)
 	c.sessionsLock.Unlock()
 
 	for _, session := range sessionToClose {

transport/anytls/session/frame.go

@@ -9,9 +9,14 @@ const ( // cmds
 	cmdSYN                 = 1 // stream open
 	cmdPSH                 = 2 // data push
 	cmdFIN                 = 3 // stream close, a.k.a EOF mark
-	cmdSettings            = 4 // Settings
+	cmdSettings            = 4 // Settings (Client send to Server)
 	cmdAlert               = 5 // Alert
 	cmdUpdatePaddingScheme = 6 // update padding scheme
+	// Since version 2
+	cmdSYNACK         = 7  // Server reports to the client that the stream has been opened
+	cmdHeartRequest   = 8  // Keep alive command
+	cmdHeartResponse  = 9  // Keep alive command
+	cmdServerSettings = 10 // Settings (Server send to client)
 )
 
 const (

transport/anytls/session/session.go

@@ -3,9 +3,11 @@ package session
 import (
 	"crypto/md5"
 	"encoding/binary"
+	"fmt"
 	"io"
 	"net"
 	"runtime/debug"
+	"strconv"
 	"sync"
 	"time"
 
@@ -30,11 +32,16 @@ type Session struct {
 	die     chan struct{}
 	dieHook func()
 
+	synDone     func()
+	synDoneLock sync.Mutex
+
 	// pool
 	seq       uint64
 	idleSince time.Time
 	padding   *atomic.TypedValue[*padding.PaddingFactory]
 
+	peerVersion byte
+
 	// client
 	isClient    bool
 	sendPadding bool
@@ -76,7 +83,7 @@ func (s *Session) Run() {
 	}
 
 	settings := util.StringMap{
-		"v":           "1",
+		"v":           "2",
 		"client":      "mihomo/" + constant.Version,
 		"padding-md5": s.padding.Load().Md5,
 	}
@@ -105,15 +112,16 @@ func (s *Session) Close() error {
 		close(s.die)
 		once = true
 	})
-
 	if once {
 		if s.dieHook != nil {
 			s.dieHook()
+			s.dieHook = nil
 		}
 		s.streamLock.Lock()
-		for k := range s.streams {
-			s.streams[k].sessionClose()
+		for _, stream := range s.streams {
+			stream.Close()
 		}
+		s.streams = make(map[uint32]*Stream)
 		s.streamLock.Unlock()
 		return s.conn.Close()
 	} else {
@@ -132,6 +140,17 @@ func (s *Session) OpenStream() (*Stream, error) {
 
 	//logrus.Debugln("stream open", sid, s.streams)
 
+	if sid >= 2 && s.peerVersion >= 2 {
+		s.synDoneLock.Lock()
+		if s.synDone != nil {
+			s.synDone()
+		}
+		s.synDone = util.NewDeadlineWatcher(time.Second*3, func() {
+			s.Close()
+		})
+		s.synDoneLock.Unlock()
+	}
+
 	if _, err := s.writeFrame(newFrame(cmdSYN, sid)); err != nil {
 		return nil, err
 	}
@@ -195,13 +214,37 @@ func (s *Session) recvLoop() error {
 				if _, ok := s.streams[sid]; !ok {
 					stream := newStream(sid, s)
 					s.streams[sid] = stream
-					if s.onNewStream != nil {
-						go s.onNewStream(stream)
-					} else {
-						go s.Close()
-					}
+					go func() {
+						if s.onNewStream != nil {
+							s.onNewStream(stream)
+						} else {
+							stream.Close()
+						}
+					}()
 				}
 				s.streamLock.Unlock()
+			case cmdSYNACK: // should be client only
+				s.synDoneLock.Lock()
+				if s.synDone != nil {
+					s.synDone()
+					s.synDone = nil
+				}
+				s.synDoneLock.Unlock()
+				if hdr.Length() > 0 {
+					buffer := pool.Get(int(hdr.Length()))
+					if _, err := io.ReadFull(s.conn, buffer); err != nil {
+						pool.Put(buffer)
+						return err
+					}
+					// report error
+					s.streamLock.RLock()
+					stream, ok := s.streams[sid]
+					s.streamLock.RUnlock()
+					if ok {
+						stream.CloseWithError(fmt.Errorf("remote: %s", string(buffer)))
+					}
+					pool.Put(buffer)
+				}
 			case cmdFIN:
 				s.streamLock.RLock()
 				stream, ok := s.streams[sid]
@@ -240,6 +283,20 @@ func (s *Session) recvLoop() error {
 								return err
 							}
 						}
+						// check client's version
+						if v, err := strconv.Atoi(m["v"]); err == nil && v >= 2 {
+							s.peerVersion = byte(v)
+							// send cmdServerSettings
+							f := newFrame(cmdServerSettings, 0)
+							f.data = util.StringMap{
+								"v": "2",
+							}.ToBytes()
+							_, err = s.writeFrame(f)
+							if err != nil {
+								pool.Put(buffer)
+								return err
+							}
+						}
 					}
 					pool.Put(buffer)
 				}
@@ -265,12 +322,35 @@ func (s *Session) recvLoop() error {
 					}
 					if s.isClient {
 						if padding.UpdatePaddingScheme(rawScheme, s.padding) {
-							log.Infoln("[Update padding succeed] %x\n", md5.Sum(rawScheme))
+							log.Debugln("[Update padding succeed] %x\n", md5.Sum(rawScheme))
 						} else {
 							log.Warnln("[Update padding failed] %x\n", md5.Sum(rawScheme))
 						}
 					}
 				}
+			case cmdHeartRequest:
+				if _, err := s.writeFrame(newFrame(cmdHeartResponse, sid)); err != nil {
+					return err
+				}
+			case cmdHeartResponse:
+				// Active keepalive checking is not implemented yet
+				break
+			case cmdServerSettings:
+				if hdr.Length() > 0 {
+					buffer := pool.Get(int(hdr.Length()))
+					if _, err := io.ReadFull(s.conn, buffer); err != nil {
+						pool.Put(buffer)
+						return err
+					}
+					if s.isClient {
+						// check server's version
+						m := util.StringMapFromBytes(buffer)
+						if v, err := strconv.Atoi(m["v"]); err == nil {
+							s.peerVersion = byte(v)
+						}
+					}
+					pool.Put(buffer)
+				}
 			default:
 				// I don't know what command it is (can't have data)
 			}
@@ -280,8 +360,10 @@ func (s *Session) recvLoop() error {
 	}
 }
 
-// notify the session that a stream has closed
 func (s *Session) streamClosed(sid uint32) error {
+	if s.IsClosed() {
+		return io.ErrClosedPipe
+	}
 	_, err := s.writeFrame(newFrame(cmdFIN, sid))
 	s.streamLock.Lock()
 	delete(s.streams, sid)

transport/anytls/session/stream.go

@@ -22,6 +22,9 @@ type Stream struct {
 
 	dieOnce sync.Once
 	dieHook func()
+	dieErr  error
+
+	reportOnce sync.Once
 }
 
 // newStream initiates a Stream struct
@@ -36,7 +39,11 @@ func newStream(id uint32, sess *Session) *Stream {
 
 // Read implements net.Conn
 func (s *Stream) Read(b []byte) (n int, err error) {
-	return s.pipeR.Read(b)
+	n, err = s.pipeR.Read(b)
+	if s.dieErr != nil {
+		err = s.dieErr
+	}
+	return
 }
 
 // Write implements net.Conn
@@ -54,25 +61,28 @@ func (s *Stream) Write(b []byte) (n int, err error) {
 
 // Close implements net.Conn
 func (s *Stream) Close() error {
-	if s.sessionClose() {
-		// notify remote
-		return s.sess.streamClosed(s.id)
-	} else {
-		return io.ErrClosedPipe
-	}
+	return s.CloseWithError(io.ErrClosedPipe)
 }
 
-// sessionClose close stream from session side, do not notify remote
-func (s *Stream) sessionClose() (once bool) {
+func (s *Stream) CloseWithError(err error) error {
+	// if err != io.ErrClosedPipe {
+	// 	logrus.Debugln(err)
+	// }
+	var once bool
 	s.dieOnce.Do(func() {
+		s.dieErr = err
 		s.pipeR.Close()
 		once = true
+	})
+	if once {
 		if s.dieHook != nil {
 			s.dieHook()
 			s.dieHook = nil
 		}
-	})
-	return
+		return s.sess.streamClosed(s.id)
+	} else {
+		return s.dieErr
+	}
 }
 
 func (s *Stream) SetReadDeadline(t time.Time) error {
@@ -108,3 +118,33 @@ func (s *Stream) RemoteAddr() net.Addr {
 	}
 	return nil
 }
+
+// HandshakeFailure should be called when Server fail to create outbound proxy
+func (s *Stream) HandshakeFailure(err error) error {
+	var once bool
+	s.reportOnce.Do(func() {
+		once = true
+	})
+	if once && err != nil && s.sess.peerVersion >= 2 {
+		f := newFrame(cmdSYNACK, s.id)
+		f.data = []byte(err.Error())
+		if _, err := s.sess.writeFrame(f); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// HandshakeSuccess should be called when Server success to create outbound proxy
+func (s *Stream) HandshakeSuccess() error {
+	var once bool
+	s.reportOnce.Do(func() {
+		once = true
+	})
+	if once && s.sess.peerVersion >= 2 {
+		if _, err := s.sess.writeFrame(newFrame(cmdSYNACK, s.id)); err != nil {
+			return err
+		}
+	}
+	return nil
+}

transport/anytls/util/deadline.go

@@ -0,0 +1,25 @@
+package util
+
+import (
+	"sync"
+	"time"
+)
+
+func NewDeadlineWatcher(ddl time.Duration, timeOut func()) (done func()) {
+	t := time.NewTimer(ddl)
+	closeCh := make(chan struct{})
+	go func() {
+		defer t.Stop()
+		select {
+		case <-closeCh:
+		case <-t.C:
+			timeOut()
+		}
+	}()
+	var once sync.Once
+	return func() {
+		once.Do(func() {
+			close(closeCh)
+		})
+	}
+}