optimize(sniffer): wait data for 300ms instead of 100ms

component/sniffing/sniffer.go

@@ -11,6 +11,10 @@ import (
 	"time"
 )
 
+const (
+	DataWaitingTimeout = 300 * time.Millisecond
+)
+
 type Sniffer struct {
 	// Stream
 	stream    bool
@@ -70,14 +74,14 @@ func (s *Sniffer) SniffTcp() (d string, err error) {
 			close(s.dataReady)
 		}()
 
-		// Waiting 100ms for data.
+		// Waiting 300ms for data.
 		select {
-		case <-time.After(100 * time.Millisecond):
-			return "", NotApplicableError
 		case <-s.dataReady:
 			if s.dataError != nil {
 				return "", s.dataError
 			}
+		case <-time.After(DataWaitingTimeout):
+			return "", NotApplicableError
 		}
 	} else {
 		close(s.dataReady)
@@ -112,14 +116,19 @@ func (s *Sniffer) SniffUdp() (d string, err error) {
 
 func (s *Sniffer) Read(p []byte) (n int, err error) {
 	<-s.dataReady
-	if s.dataError != nil {
-		return 0, s.dataError
-	}
 
 	s.readMu.Lock()
 	defer s.readMu.Unlock()
 
-	if s.buf != nil && s.bufAt < len(s.buf) {
+	if s.dataError != nil {
+		if s.bufAt < len(s.buf) {
+			n = copy(p, s.buf[s.bufAt:])
+			s.bufAt += n
+		}
+		return n, s.dataError
+	}
+
+	if s.bufAt < len(s.buf) {
 		// Read buf first.
 		n = copy(p, s.buf[s.bufAt:])
 		s.bufAt += n

control/tcp.go

@@ -30,12 +30,12 @@ func (c *ControlPlane) handleConn(lConn net.Conn) (err error) {
 
 	// Sniff target domain.
 	sniffer := sniffing.NewConnSniffer(lConn, TcpSniffBufSize)
+	// ConnSniffer should be used later, so we cannot close it now.
+	defer sniffer.Close()
 	domain, err := sniffer.SniffTcp()
 	if err != nil && !sniffing.IsSniffingError(err) {
 		return err
 	}
-	// ConnSniffer should be used later, so we cannot close it now.
-	defer sniffer.Close()
 
 	// Get tuples and outbound.
 	src := lConn.RemoteAddr().(*net.TCPAddr).AddrPort()

control/udp.go

@@ -129,12 +129,11 @@ func (c *ControlPlane) handlePkt(lConn *net.UDPConn, data []byte, src, pktDst, r
 	if !isDns {
 		// Sniff Quic, ...
 		sniffer := sniffing.NewPacketSniffer(data)
+		defer sniffer.Close()
 		domain, err = sniffer.SniffUdp()
 		if err != nil && !sniffing.IsSniffingError(err) {
-			sniffer.Close()
 			return err
 		}
-		sniffer.Close()
 	}
 
 	// Get outbound.