fix: when data is not enough, attempt to peek more data and retry

component/sniffer/dispatcher.go

@@ -173,6 +173,19 @@ func (sd *Dispatcher) sniffDomain(conn *N.BufferedConn, metadata *C.Metadata) (s
 			}
 
 			host, err := s.SniffData(bytes)
+			var e *errNeedAtLeastData
+			if errors.As(err, &e) {
+				log.Debugln("[Sniffer] [%s] [%s] %v, got length: %d", metadata.DstIP, s.Protocol(), e, len(bytes))
+				_ = conn.SetReadDeadline(time.Now().Add(1 * time.Second))
+				bytes, err = conn.Peek(e.length)
+				_ = conn.SetReadDeadline(time.Time{})
+				log.Debugln("[Sniffer] [%s] [%s] try again, got length: %d", metadata.DstIP, s.Protocol(), len(bytes))
+				if err != nil {
+					log.Debugln("[Sniffer] [%s] [%s] the data length not enough, error: %v", metadata.DstIP, s.Protocol(), err)
+					continue
+				}
+				host, err = s.SniffData(bytes)
+			}
 			if err != nil {
 				log.Debugln("[Sniffer] [%s] [%s] Sniff data failed, error: %v", metadata.DstIP, s.Protocol(), err)
 				continue

component/sniffer/tls_sniffer.go

@@ -3,6 +3,7 @@ package sniffer
 import (
 	"encoding/binary"
 	"errors"
+	"fmt"
 	"strings"
 
 	"github.com/metacubex/mihomo/common/utils"
@@ -15,6 +16,19 @@ var (
 	errNotClientHello = errors.New("not client hello")
 )
 
+type errNeedAtLeastData struct {
+	length int
+	err    error
+}
+
+func (e *errNeedAtLeastData) Error() string {
+	return fmt.Sprintf("%v, need at least length: %d", e.err, e.length)
+}
+
+func (e *errNeedAtLeastData) Unwrap() error {
+	return e.err
+}
+
 var _ sniffer.Sniffer = (*TLSSniffer)(nil)
 
 type TLSSniffer struct {
@@ -160,7 +174,10 @@ func SniffTLS(b []byte) (*string, error) {
 	}
 	headerLen := int(binary.BigEndian.Uint16(b[3:5]))
 	if 5+headerLen > len(b) {
-		return nil, ErrNoClue
+		return nil, &errNeedAtLeastData{
+			length: 5 + headerLen,
+			err:    ErrNoClue,
+		}
 	}
 
 	domain, err := ReadClientHello(b[5 : 5+headerLen])