Fix h2c transport

transport/v2rayhttp/server.go

@@ -16,6 +16,9 @@ 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
 	host         []string
 	path         string
 	method       string
@@ -44,6 +49,7 @@ func NewServer(ctx context.Context, options option.V2RayHTTPOptions, tlsConfig *
 		path:         options.Path,
 		method:       options.Method,
 		headers:      make(http.Header),
+		h2Server:     new(http2.Server),
 	}
 	if server.method == "" {
 		server.method = "PUT"
@@ -60,10 +66,16 @@ func NewServer(ctx context.Context, options option.V2RayHTTPOptions, tlsConfig *
 		MaxHeaderBytes:    http.DefaultMaxHeaderBytes,
 		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
+	}
+
 	host := request.Host
 	if len(s.host) > 0 && !common.Contains(s.host, host) {
 		writer.WriteHeader(http.StatusBadRequest)
@@ -119,6 +131,10 @@ 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 {