Fix h2c transport

transport/v2raygrpclite/server.go

@@ -17,6 +17,9 @@ import (
 	M "github.com/sagernet/sing/common/metadata"
 	N "github.com/sagernet/sing/common/network"
 	sHttp "github.com/sagernet/sing/protocol/http"
+
+	"golang.org/x/net/http2"
+	"golang.org/x/net/http2/h2c"
 )
 
 var _ adapter.V2RayServerTransport = (*Server)(nil)
@@ -25,6 +28,8 @@ type Server struct {
 	handler      N.TCPConnectionHandler
 	errorHandler E.Handler
 	httpServer   *http.Server
+	h2Server     *http2.Server
+	h2cHandler   http.Handler
 	path         string
 }
 
@@ -37,6 +42,7 @@ func NewServer(ctx context.Context, options option.V2RayGRPCOptions, tlsConfig *
 		handler:      handler,
 		errorHandler: errorHandler,
 		path:         fmt.Sprintf("/%s/Tun", url.QueryEscape(options.ServiceName)),
+		h2Server:     new(http2.Server),
 	}
 	if tlsConfig != nil {
 		if !common.Contains(tlsConfig.NextProtos, "h2") {
@@ -47,10 +53,15 @@ func NewServer(ctx context.Context, options option.V2RayGRPCOptions, tlsConfig *
 		Handler:   server,
 		TLSConfig: tlsConfig,
 	}
+	server.h2cHandler = h2c.NewHandler(server, server.h2Server)
 	return server
 }
 
 func (s *Server) ServeHTTP(writer http.ResponseWriter, request *http.Request) {
+	if request.Method == "PRI" && len(request.Header) == 0 && request.URL.Path == "*" && request.Proto == "HTTP/2.0" {
+		s.h2cHandler.ServeHTTP(writer, request)
+		return
+	}
 	if request.URL.Path != s.path {
 		writer.WriteHeader(http.StatusNotFound)
 		s.badRequest(request, E.New("bad path: ", request.URL.Path))
@@ -80,6 +91,10 @@ func (s *Server) badRequest(request *http.Request, err error) {
 }
 
 func (s *Server) Serve(listener net.Listener) error {
+	err := http2.ConfigureServer(s.httpServer, s.h2Server)
+	if err != nil {
+		return err
+	}
 	if s.httpServer.TLSConfig == nil {
 		return s.httpServer.Serve(listener)
 	} else {