fix: quic sniffer should not replace domain when no valid host is read

component/sniffer/quic_sniffer.go

@@ -88,7 +88,7 @@ type quicPacketSender struct {
 	lock     sync.RWMutex
 	ranges   utils.IntRanges[uint64]
 	buffer   []byte
-	result   string
+	result   *string
 	override bool
 
 	constant.PacketSender
@@ -121,7 +121,10 @@ func (q *quicPacketSender) DoSniff(metadata *constant.Metadata) error {
 	select {
 	case <-q.chClose:
 		q.lock.RLock()
-		replaceDomain(metadata, q.result, q.override)
+		if q.result != nil {
+			host := *q.result
+			replaceDomain(metadata, host, q.override)
+		}
 		q.lock.RUnlock()
 		break
 	case <-time.After(quicWaitConn):
@@ -428,7 +431,7 @@ func (q *quicPacketSender) tryAssemble() error {
 	}
 
 	q.lock.Lock()
-	q.result = *domain
+	q.result = domain
 	q.closeLocked()
 	q.lock.Unlock()
 

component/sniffer/sniff_test.go

@@ -67,10 +67,12 @@ func asPacket(data string) constant.PacketAdapter {
 	return pktAdp
 }
 
-func testQuicSniffer(data []string, async bool) (string, error) {
+const fakeHost = "fake.host.com"
+
+func testQuicSniffer(data []string, async bool) (string, string, error) {
 	q, err := NewQuicSniffer(SnifferConfig{})
 	if err != nil {
-		return "", err
+		return "", "", err
 	}
 
 	resultCh := make(chan *constant.Metadata, 1)
@@ -79,7 +81,7 @@ func testQuicSniffer(data []string, async bool) (string, error) {
 	sender := q.WrapperSender(emptySender, true)
 
 	go func() {
-		meta := constant.Metadata{}
+		meta := constant.Metadata{Host: fakeHost}
 		err := sender.DoSniff(&meta)
 		if err != nil {
 			panic(err)
@@ -96,14 +98,15 @@ func testQuicSniffer(data []string, async bool) (string, error) {
 	}
 
 	meta := <-resultCh
-	return meta.SniffHost, nil
+	return meta.SniffHost, meta.Host, nil
 }
 
 func TestQuicHeaders(t *testing.T) {
 
 	cases := []struct {
-		input  []string
-		domain string
+		input   []string
+		domain  string
+		invalid bool
 	}{
 		//Normal domain quic sniff
 		{
@@ -161,16 +164,31 @@ func TestQuicHeaders(t *testing.T) {
 			},
 			domain: "www.google.com",
 		},
+		// invalid packet
+		{
+			input:   []string{"00000000000000000000"},
+			invalid: true,
+		},
 	}
 
 	for _, test := range cases {
-		data, err := testQuicSniffer(test.input, true)
+		data, host, err := testQuicSniffer(test.input, true)
 		assert.NoError(t, err)
 		assert.Equal(t, test.domain, data)
+		if test.invalid {
+			assert.Equal(t, fakeHost, host)
+		} else {
+			assert.Equal(t, test.domain, host)
+		}
 
-		data, err = testQuicSniffer(test.input, false)
+		data, host, err = testQuicSniffer(test.input, false)
 		assert.NoError(t, err)
 		assert.Equal(t, test.domain, data)
+		if test.invalid {
+			assert.Equal(t, fakeHost, host)
+		} else {
+			assert.Equal(t, test.domain, host)
+		}
 	}
 }