send a Public Reset when receiving the NSTP tag in the CHLO

We currently don't support the no STOP_WAITING experiment.

handshake/crypto_setup_server.go

@@ -54,11 +54,15 @@ type cryptoSetupServer struct {
 
 var _ CryptoSetup = &cryptoSetupServer{}
 
-// ErrHOLExperiment is returned when the client sends the FHL2 tag in the CHLO
-// this is an expiremnt implemented by Chrome in QUIC 36, which we don't support
+// ErrHOLExperiment is returned when the client sends the FHL2 tag in the CHLO.
+// This is an experiment implemented by Chrome in QUIC 36, which we don't support.
 // TODO: remove this when dropping support for QUIC 36
 var ErrHOLExperiment = qerr.Error(qerr.InvalidCryptoMessageParameter, "HOL experiment. Unsupported")
 
+// ErrNSTPExperiment is returned when the client sends the NSTP tag in the CHLO.
+// This is an experiment implemented by Chrome in QUIC 38, which we don't support at this point.
+var ErrNSTPExperiment = qerr.Error(qerr.InvalidCryptoMessageParameter, "NSTP experiment. Unsupported")
+
 // NewCryptoSetup creates a new CryptoSetup instance for a server
 func NewCryptoSetup(
 	connID protocol.ConnectionID,
@@ -120,6 +124,9 @@ func (h *cryptoSetupServer) handleMessage(chloData []byte, cryptoData map[Tag][]
 	if _, isHOLExperiment := cryptoData[TagFHL2]; isHOLExperiment {
 		return false, ErrHOLExperiment
 	}
+	if _, isNSTPExperiment := cryptoData[TagNSTP]; isNSTPExperiment {
+		return false, ErrNSTPExperiment
+	}
 
 	sniSlice, ok := cryptoData[TagSNI]
 	if !ok {

handshake/crypto_setup_server_test.go

@@ -264,6 +264,17 @@ var _ = Describe("Server Crypto Setup", func() {
 			Expect(err).To(MatchError(ErrHOLExperiment))
 		})
 
+		It("doesn't support Chrome's no STOP_WAITING experiment", func() {
+			HandshakeMessage{
+				Tag: TagCHLO,
+				Data: map[Tag][]byte{
+					TagNSTP: []byte("foobar"),
+				},
+			}.Write(&stream.dataToRead)
+			err := cs.HandleCryptoStream()
+			Expect(err).To(MatchError(ErrNSTPExperiment))
+		})
+
 		It("generates REJ messages", func() {
 			sourceAddrValid = false
 			response, err := cs.handleInchoateCHLO("", bytes.Repeat([]byte{'a'}, protocol.ClientHelloMinimumSize), nil)

handshake/tags.go

@@ -54,6 +54,9 @@ const (
 	// Chrome experiment (see https://codereview.chromium.org/2115033002)
 	// unsupported by quic-go
 	TagFHL2 Tag = 'F' + 'H'<<8 + 'L'<<16 + '2'<<24
+	// TagNSTP is the no STOP_WAITING experiment
+	// currently unsupported by quic-go
+	TagNSTP Tag = 'N' + 'S'<<8 + 'T'<<16 + 'P'<<24
 
 	// TagSTK is the source-address token
 	TagSTK Tag = 'S' + 'T'<<8 + 'K'<<16

session.go

@@ -578,7 +578,9 @@ func (s *session) handleCloseError(closeErr closeError) error {
 		return nil
 	}
 
-	if quicErr.ErrorCode == qerr.DecryptionFailure || quicErr == handshake.ErrHOLExperiment {
+	if quicErr.ErrorCode == qerr.DecryptionFailure ||
+		quicErr == handshake.ErrHOLExperiment ||
+		quicErr == handshake.ErrNSTPExperiment {
 		return s.sendPublicReset(s.lastRcvdPacketNumber)
 	}
 	return s.sendConnectionClose(quicErr)

session_test.go

@@ -804,6 +804,13 @@ var _ = Describe("Session", func() {
 			Expect(sess.Context().Done()).To(BeClosed())
 		})
 
+		It("sends a Public Reset if the client is initiating the no STOP_WAITING experiment", func() {
+			sess.Close(handshake.ErrHOLExperiment)
+			Expect(mconn.written).To(HaveLen(1))
+			Expect(mconn.written[0][0] & 0x02).ToNot(BeZero()) // Public Reset
+			Expect(sess.Context().Done()).To(BeClosed())
+		})
+
 		It("cancels the context when the run loop exists", func() {
 			returned := make(chan struct{})
 			go func() {