http3: add http3.Server.ServeQUICConn to serve a single QUIC connection (#3587)

http3/server.go

@@ -226,11 +226,22 @@ func (s *Server) ListenAndServeTLS(certFile, keyFile string) error {
 
 // Serve an existing UDP connection.
 // It is possible to reuse the same connection for outgoing connections.
-// Closing the server does not close the packet conn.
+// Closing the server does not close the connection.
 func (s *Server) Serve(conn net.PacketConn) error {
 	return s.serveConn(s.TLSConfig, conn)
 }
 
+// ServeQUICConn serves a single QUIC connection.
+func (s *Server) ServeQUICConn(conn quic.Connection) error {
+	s.mutex.Lock()
+	if s.logger == nil {
+		s.logger = utils.DefaultLogger.WithPrefix("server")
+	}
+	s.mutex.Unlock()
+
+	return s.handleConn(conn)
+}
+
 // ServeListener serves an existing QUIC listener.
 // Make sure you use http3.ConfigureTLSConfig to configure a tls.Config
 // and use it to construct a http3-friendly QUIC listener.
@@ -297,7 +308,11 @@ func (s *Server) serveListener(ln quic.EarlyListener) error {
 		if err != nil {
 			return err
 		}
-		go s.handleConn(conn)
+		go func() {
+			if err := s.handleConn(conn); err != nil {
+				s.logger.Debugf(err.Error())
+			}
+		}()
 	}
 }
 
@@ -405,14 +420,13 @@ func (s *Server) removeListener(l *quic.EarlyListener) {
 	s.mutex.Unlock()
 }
 
-func (s *Server) handleConn(conn quic.EarlyConnection) {
+func (s *Server) handleConn(conn quic.Connection) error {
 	decoder := qpack.NewDecoder(nil)
 
 	// send a SETTINGS frame
 	str, err := conn.OpenUniStream()
 	if err != nil {
-		s.logger.Debugf("Opening the control stream failed.")
-		return
+		return fmt.Errorf("opening the control stream failed: %w", err)
 	}
 	b := make([]byte, 0, 64)
 	b = quicvarint.Append(b, streamTypeControlStream) // stream type
@@ -426,8 +440,11 @@ func (s *Server) handleConn(conn quic.EarlyConnection) {
 	for {
 		str, err := conn.AcceptStream(context.Background())
 		if err != nil {
-			s.logger.Debugf("Accepting stream failed: %s", err)
-			return
+			var appErr *quic.ApplicationError
+			if errors.As(err, &appErr) && appErr.ErrorCode == quic.ApplicationErrorCode(errorNoError) {
+				return nil
+			}
+			return fmt.Errorf("accepting stream failed: %w", err)
 		}
 		go func() {
 			rerr := s.handleRequest(conn, str, decoder, func() {
@@ -455,7 +472,7 @@ func (s *Server) handleConn(conn quic.EarlyConnection) {
 	}
 }
 
-func (s *Server) handleUnidirectionalStreams(conn quic.EarlyConnection) {
+func (s *Server) handleUnidirectionalStreams(conn quic.Connection) {
 	for {
 		str, err := conn.AcceptUniStream(context.Background())
 		if err != nil {

http3/server_test.go

@@ -1151,6 +1151,30 @@ var _ = Describe("Server", func() {
 		})
 	})
 
+	Context("ServeQUICConn", func() {
+		It("serves a QUIC connection", func() {
+			mux := http.NewServeMux()
+			mux.HandleFunc("/hello", func(w http.ResponseWriter, _ *http.Request) {
+				w.Write([]byte("foobar"))
+			})
+			s.Handler = mux
+			tlsConf := testdata.GetTLSConfig()
+			tlsConf.NextProtos = []string{NextProtoH3}
+			conn := mockquic.NewMockEarlyConnection(mockCtrl)
+			controlStr := mockquic.NewMockStream(mockCtrl)
+			controlStr.EXPECT().Write(gomock.Any())
+			conn.EXPECT().OpenUniStream().Return(controlStr, nil)
+			testDone := make(chan struct{})
+			conn.EXPECT().AcceptUniStream(gomock.Any()).DoAndReturn(func(context.Context) (quic.ReceiveStream, error) {
+				<-testDone
+				return nil, errors.New("test done")
+			}).MaxTimes(1)
+			conn.EXPECT().AcceptStream(gomock.Any()).Return(nil, &quic.ApplicationError{ErrorCode: quic.ApplicationErrorCode(errorNoError)})
+			s.ServeQUICConn(conn)
+			close(testDone)
+		})
+	})
+
 	Context("ListenAndServe", func() {
 		BeforeEach(func() {
 			s.Addr = "localhost:0"