XHTTP server: Switch to native h2c support (#4451)

Author: yin1999

Diff for: transport/internet/splithttp/hub.go

@@ -24,8 +24,6 @@ import (
 	"github.com/xtls/xray-core/transport/internet/reality"
 	"github.com/xtls/xray-core/transport/internet/stat"
 	"github.com/xtls/xray-core/transport/internet/tls"
-	"golang.org/x/net/http2"
-	"golang.org/x/net/http2/h2c"
 )
 
 type requestHandler struct {
@@ -426,11 +424,15 @@ func ListenXH(ctx context.Context, address net.Address, port net.Port, streamSet
 
 		handler.localAddr = l.listener.Addr()
 
-		// h2cHandler can handle both plaintext HTTP/1.1 and h2c
+		// server can handle both plaintext HTTP/1.1 and h2c
+		protocols := new(http.Protocols)
+		protocols.SetHTTP1(true)
+		protocols.SetUnencryptedHTTP2(true)
 		l.server = http.Server{
-			Handler:           h2c.NewHandler(handler, &http2.Server{}),
+			Handler:           handler,
 			ReadHeaderTimeout: time.Second * 4,
 			MaxHeaderBytes:    8192,
+			Protocols:         protocols,
 		}
 		go func() {
 			if err := l.server.Serve(l.listener); err != nil {

Diff for: transport/internet/splithttp/splithttp_test.go

@@ -3,10 +3,8 @@ package splithttp_test
 import (
 	"context"
 	"crypto/rand"
-	gotls "crypto/tls"
 	"fmt"
 	"io"
-	gonet "net"
 	"net/http"
 	"runtime"
 	"testing"
@@ -23,7 +21,6 @@ import (
 	. "github.com/xtls/xray-core/transport/internet/splithttp"
 	"github.com/xtls/xray-core/transport/internet/stat"
 	"github.com/xtls/xray-core/transport/internet/tls"
-	"golang.org/x/net/http2"
 )
 
 func Test_ListenXHAndDial(t *testing.T) {
@@ -201,17 +198,11 @@ func Test_ListenXHAndDial_H2C(t *testing.T) {
 	common.Must(err)
 	defer listen.Close()
 
+	protocols := new(http.Protocols)
+	protocols.SetUnencryptedHTTP2(true)
 	client := http.Client{
-		Transport: &http2.Transport{
-			// So http2.Transport doesn't complain the URL scheme isn't 'https'
-			AllowHTTP: true,
-			// even with AllowHTTP, http2.Transport will attempt to establish
-			// the connection using DialTLSContext. Disable TLS with custom
-			// dial context.
-			DialTLSContext: func(ctx context.Context, network, addr string, cfg *gotls.Config) (gonet.Conn, error) {
-				var d gonet.Dialer
-				return d.DialContext(ctx, network, addr)
-			},
+		Transport: &http.Transport{
+			Protocols: protocols,
 		},
 	}