fixed a bug that smux.OpenStream /smux.Close will hang forever in rare

case

go.mod

@@ -5,7 +5,7 @@ require (
 	github.com/pkg/errors v0.9.1
 	github.com/urfave/cli v1.22.12
 	github.com/xtaci/kcp-go/v5 v5.6.2
-	github.com/xtaci/smux v1.5.19
+	github.com/xtaci/smux v1.5.24
 	github.com/xtaci/tcpraw v1.2.25
 	golang.org/x/crypto v0.5.0
 )

go.sum

@@ -70,10 +70,8 @@ github.com/xtaci/kcp-go/v5 v5.6.2 h1:pSXMa5MOsb+EIZKe4sDBqlTExu2A/2Z+DFhoX2qtt2A
 github.com/xtaci/kcp-go/v5 v5.6.2/go.mod h1:LsinWoru+lWWJHb+EM9HeuqYxV6bb9rNcK12v67jYzQ=
 github.com/xtaci/lossyconn v0.0.0-20190602105132-8df528c0c9ae h1:J0GxkO96kL4WF+AIT3M4mfUVinOCPgf2uUWYFUzN0sM=
 github.com/xtaci/lossyconn v0.0.0-20190602105132-8df528c0c9ae/go.mod h1:gXtu8J62kEgmN++bm9BVICuT/e8yiLI2KFobd/TRFsE=
-github.com/xtaci/smux v1.5.18 h1:NRH2dIxcO1w5dsNpQxSrxfhxjk4YNg6TrS/Nj0FuUPc=
-github.com/xtaci/smux v1.5.18/go.mod h1:OMlQbT5vcgl2gb49mFkYo6SMf+zP3rcjcwQz7ZU7IGY=
-github.com/xtaci/smux v1.5.19 h1:QFoVBZPuJnoTs8QQ52TO2469nz8KxGHDpiEb+s3QzCQ=
-github.com/xtaci/smux v1.5.19/go.mod h1:OMlQbT5vcgl2gb49mFkYo6SMf+zP3rcjcwQz7ZU7IGY=
+github.com/xtaci/smux v1.5.24 h1:77emW9dtnOxxOQ5ltR+8BbsX1kzcOxQ5gB+aaV9hXOY=
+github.com/xtaci/smux v1.5.24/go.mod h1:OMlQbT5vcgl2gb49mFkYo6SMf+zP3rcjcwQz7ZU7IGY=
 github.com/xtaci/tcpraw v1.2.25 h1:VDlqo0op17JeXBM6e2G9ocCNLOJcw9mZbobMbJjo0vk=
 github.com/xtaci/tcpraw v1.2.25/go.mod h1:dKyZ2V75s0cZ7cbgJYdxPvms7af0joIeOyx1GgJQbLk=
 github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=

vendor/github.com/xtaci/smux/session.go

@@ -13,6 +13,16 @@ import (
 
 const (
 	defaultAcceptBacklog = 1024
+	maxShaperSize        = 1024
+	openCloseTimeout     = 30 * time.Second // stream open/close timeout
+)
+
+// define frame class
+type CLASSID int
+
+const (
+	CLSCTRL CLASSID = iota
+	CLSDATA
 )
 
 var (
@@ -24,7 +34,7 @@ var (
 )
 
 type writeRequest struct {
-	prio   uint32
+	class  CLASSID
 	frame  Frame
 	seq    uint32
 	result chan writeResult
@@ -35,10 +45,6 @@ type writeResult struct {
 	err error
 }
 
-type buffersWriter interface {
-	WriteBuffers(v [][]byte) (n int, err error)
-}
-
 // Session defines a multiplexed connection for streams
 type Session struct {
 	conn io.ReadWriteCloser
@@ -398,7 +404,7 @@ func (s *Session) keepalive() {
 	for {
 		select {
 		case <-tickerPing.C:
-			s.writeFrameInternal(newFrame(byte(s.config.Version), cmdNOP, 0), tickerPing.C, 0)
+			s.writeFrameInternal(newFrame(byte(s.config.Version), cmdNOP, 0), tickerPing.C, CLSCTRL)
 			s.notifyBucket() // force a signal to the recvLoop
 		case <-tickerTimeout.C:
 			if !atomic.CompareAndSwapInt32(&s.dataReady, 1, 0) {
@@ -420,8 +426,10 @@ func (s *Session) shaperLoop() {
 	var reqs shaperHeap
 	var next writeRequest
 	var chWrite chan writeRequest
+	var chShaper chan writeRequest
 
 	for {
+		// chWrite is not available until it has packet to send
 		if len(reqs) > 0 {
 			chWrite = s.writes
 			next = heap.Pop(&reqs).(writeRequest)
@@ -429,10 +437,22 @@ func (s *Session) shaperLoop() {
 			chWrite = nil
 		}
 
+		// control heap size, chShaper is not available until packets are less than maximum allowed
+		if len(reqs) >= maxShaperSize {
+			chShaper = nil
+		} else {
+			chShaper = s.shaper
+		}
+
+		// assertion on non nil
+		if chShaper == nil && chWrite == nil {
+			panic("both channel are nil")
+		}
+
 		select {
 		case <-s.die:
 			return
-		case r := <-s.shaper:
+		case r := <-chShaper:
 			if chWrite != nil { // next is valid, reshape
 				heap.Push(&reqs, next)
 			}
@@ -448,7 +468,10 @@ func (s *Session) sendLoop() {
 	var err error
 	var vec [][]byte // vector for writeBuffers
 
-	bw, ok := s.conn.(buffersWriter)
+	bw, ok := s.conn.(interface {
+		WriteBuffers(v [][]byte) (n int, err error)
+	})
+
 	if ok {
 		buf = make([]byte, headerSize)
 		vec = make([][]byte, 2)
@@ -500,13 +523,13 @@ func (s *Session) sendLoop() {
 // writeFrame writes the frame to the underlying connection
 // and returns the number of bytes written if successful
 func (s *Session) writeFrame(f Frame) (n int, err error) {
-	return s.writeFrameInternal(f, nil, 0)
+	return s.writeFrameInternal(f, time.After(openCloseTimeout), CLSCTRL)
 }
 
 // internal writeFrame version to support deadline used in keepalive
-func (s *Session) writeFrameInternal(f Frame, deadline <-chan time.Time, prio uint32) (int, error) {
+func (s *Session) writeFrameInternal(f Frame, deadline <-chan time.Time, class CLASSID) (int, error) {
 	req := writeRequest{
-		prio:   prio,
+		class:  class,
 		frame:  f,
 		seq:    atomic.AddUint32(&s.requestID, 1),
 		result: make(chan writeResult, 1),

vendor/github.com/xtaci/smux/shaper.go

@@ -6,8 +6,14 @@ func _itimediff(later, earlier uint32) int32 {
 
 type shaperHeap []writeRequest
 
-func (h shaperHeap) Len() int            { return len(h) }
-func (h shaperHeap) Less(i, j int) bool  { return _itimediff(h[j].seq, h[i].seq) > 0 }
+func (h shaperHeap) Len() int { return len(h) }
+func (h shaperHeap) Less(i, j int) bool {
+	if h[i].class != h[j].class {
+		return h[i].class < h[j].class
+	}
+	return _itimediff(h[j].seq, h[i].seq) > 0
+}
+
 func (h shaperHeap) Swap(i, j int)       { h[i], h[j] = h[j], h[i] }
 func (h *shaperHeap) Push(x interface{}) { *h = append(*h, x.(writeRequest)) }
 

vendor/github.com/xtaci/smux/stream.go

@@ -255,7 +255,7 @@ func (s *Stream) sendWindowUpdate(consumed uint32) error {
 	binary.LittleEndian.PutUint32(hdr[:], consumed)
 	binary.LittleEndian.PutUint32(hdr[4:], uint32(s.sess.config.MaxStreamBuffer))
 	frame.data = hdr[:]
-	_, err := s.sess.writeFrameInternal(frame, deadline, 0)
+	_, err := s.sess.writeFrameInternal(frame, deadline, CLSDATA)
 	return err
 }
 
@@ -325,7 +325,7 @@ func (s *Stream) Write(b []byte) (n int, err error) {
 		}
 		frame.data = bts[:sz]
 		bts = bts[sz:]
-		n, err := s.sess.writeFrameInternal(frame, deadline, s.numWritten)
+		n, err := s.sess.writeFrameInternal(frame, deadline, CLSDATA)
 		s.numWritten++
 		sent += n
 		if err != nil {
@@ -393,7 +393,7 @@ func (s *Stream) writeV2(b []byte) (n int, err error) {
 				}
 				frame.data = bts[:sz]
 				bts = bts[sz:]
-				n, err := s.sess.writeFrameInternal(frame, deadline, atomic.LoadUint32(&s.numWritten))
+				n, err := s.sess.writeFrameInternal(frame, deadline, CLSDATA)
 				atomic.AddUint32(&s.numWritten, uint32(sz))
 				sent += n
 				if err != nil {

vendor/modules.txt

@@ -38,7 +38,7 @@ github.com/urfave/cli
 # github.com/xtaci/kcp-go/v5 v5.6.2
 ## explicit; go 1.13
 github.com/xtaci/kcp-go/v5
-# github.com/xtaci/smux v1.5.19
+# github.com/xtaci/smux v1.5.24
 ## explicit; go 1.13
 github.com/xtaci/smux
 # github.com/xtaci/tcpraw v1.2.25