Add quic qlog to debug logs

transport/internet/quic/dialer.go

@@ -2,10 +2,13 @@ package quic
 
 import (
 	"context"
+	"io"
 	"sync"
 	"time"
 
 	"github.com/lucas-clemente/quic-go"
+	"github.com/lucas-clemente/quic-go/logging"
+	"github.com/lucas-clemente/quic-go/qlog"
 
 	"github.com/xtls/xray-core/common"
 	"github.com/xtls/xray-core/common/net"
@@ -140,6 +143,9 @@ func (s *clientConnections) openConnection(ctx context.Context, destAddr net.Add
 	quicConfig := &quic.Config{
 		ConnectionIDLength: 12,
 		KeepAlive:          false,
+		Tracer: qlog.NewTracer(func(_ logging.Perspective, connID []byte) io.WriteCloser {
+			return &QlogWriter{connID: connID}
+		}),
 	}
 
 	udpConn, _ := rawConn.(*net.UDPConn)

transport/internet/quic/hub.go

@@ -2,9 +2,12 @@ package quic
 
 import (
 	"context"
+	"io"
 	"time"
 
 	"github.com/lucas-clemente/quic-go"
+	"github.com/lucas-clemente/quic-go/logging"
+	"github.com/lucas-clemente/quic-go/qlog"
 
 	"github.com/xtls/xray-core/common"
 	"github.com/xtls/xray-core/common/net"
@@ -106,6 +109,9 @@ func Listen(ctx context.Context, address net.Address, port net.Port, streamSetti
 		KeepAlive:             false,
 		MaxIncomingStreams:    32,
 		MaxIncomingUniStreams: -1,
+		Tracer: qlog.NewTracer(func(_ logging.Perspective, connID []byte) io.WriteCloser {
+			return &QlogWriter{connID: connID}
+		}),
 	}
 
 	conn, err := wrapSysConn(rawConn.(*net.UDPConn), config)

transport/internet/quic/qlogWriter.go

@@ -0,0 +1,26 @@
+package quic
+
+import (
+	"fmt"
+
+	"github.com/xtls/xray-core/common/log"
+)
+
+type QlogWriter struct {
+	connID []byte
+}
+
+func (w *QlogWriter) Write(b []byte) (int, error) {
+	if len(b) > 1 { // skip line separator "0a" in qlog
+		log.Record(&log.GeneralMessage{
+			Severity: log.Severity_Debug,
+			Content:  fmt.Sprintf("[%x] %s", w.connID, b),
+		})
+	}
+	return len(b), nil
+}
+
+func (w *QlogWriter) Close() error {
+	// Noop
+	return nil
+}