accept the control stream and parse SETTINGS frame, for the H3 server

http3/server.go

@@ -37,8 +37,9 @@ var (
 )
 
 const (
-	nextProtoH3Draft29 = "h3-29"
-	nextProtoH3Draft32 = "h3-32"
+	nextProtoH3Draft29      = "h3-29"
+	nextProtoH3Draft32      = "h3-32"
+	streamTypeControlStream = 0
 )
 
 func versionToALPN(v protocol.VersionNumber) string {
@@ -219,10 +220,13 @@ func (s *Server) handleConn(sess quic.EarlySession) {
 		s.logger.Debugf("Opening the control stream failed.")
 		return
 	}
-	buf := bytes.NewBuffer([]byte{0})
+	buf := &bytes.Buffer{}
+	utils.WriteVarInt(buf, streamTypeControlStream) // stream type
 	(&settingsFrame{}).Write(buf)
 	str.Write(buf.Bytes())
 
+	go s.handleUnidirectionalStreams(sess)
+
 	// Process all requests immediately.
 	// It's the client's responsibility to decide which requests are eligible for 0-RTT.
 	for {
@@ -254,6 +258,35 @@ func (s *Server) handleConn(sess quic.EarlySession) {
 	}
 }
 
+func (s *Server) handleUnidirectionalStreams(sess quic.EarlySession) {
+	for {
+		str, err := sess.AcceptUniStream(context.Background())
+		if err != nil {
+			s.logger.Debugf("accepting unidirectional stream failed: %s", err)
+			return
+		}
+
+		go func(str quic.ReceiveStream) {
+			streamType, err := utils.ReadVarInt(&byteReaderImpl{str})
+			if err != nil {
+				s.logger.Debugf("reading stream type on stream %d failed: %s", str.StreamID(), err)
+				return
+			}
+			if streamType != streamTypeControlStream {
+				return
+			}
+			f, err := parseNextFrame(str)
+			if err != nil {
+				sess.CloseWithError(quic.ErrorCode(errorFrameError), "")
+				return
+			}
+			if _, ok := f.(*settingsFrame); !ok {
+				sess.CloseWithError(quic.ErrorCode(errorMissingSettings), "")
+			}
+		}(str)
+	}
+}
+
 func (s *Server) maxHeaderBytes() uint64 {
 	if s.Server.MaxHeaderBytes <= 0 {
 		return http.DefaultMaxHeaderBytes