init: fork

analyzer/udp/quic.go

@@ -0,0 +1,81 @@
+package udp
+
+import (
+	"github.com/DifuseHQ/Mellaris/analyzer"
+	"github.com/DifuseHQ/Mellaris/analyzer/internal"
+	"github.com/DifuseHQ/Mellaris/analyzer/udp/internal/quic"
+	"github.com/DifuseHQ/Mellaris/analyzer/utils"
+)
+
+const (
+	quicInvalidCountThreshold = 4
+)
+
+var (
+	_ analyzer.UDPAnalyzer = (*QUICAnalyzer)(nil)
+	_ analyzer.UDPStream   = (*quicStream)(nil)
+)
+
+type QUICAnalyzer struct{}
+
+func (a *QUICAnalyzer) Name() string {
+	return "quic"
+}
+
+func (a *QUICAnalyzer) Limit() int {
+	return 0
+}
+
+func (a *QUICAnalyzer) NewUDP(info analyzer.UDPInfo, logger analyzer.Logger) analyzer.UDPStream {
+	return &quicStream{logger: logger}
+}
+
+type quicStream struct {
+	logger       analyzer.Logger
+	invalidCount int
+}
+
+func (s *quicStream) Feed(rev bool, data []byte) (u *analyzer.PropUpdate, done bool) {
+	// minimal data size: protocol version (2 bytes) + random (32 bytes) +
+	//   + session ID (1 byte) + cipher suites (4 bytes) +
+	//   + compression methods (2 bytes) + no extensions
+	const minDataSize = 41
+
+	if rev {
+		// We don't support server direction for now
+		s.invalidCount++
+		return nil, s.invalidCount >= quicInvalidCountThreshold
+	}
+
+	pl, err := quic.ReadCryptoPayload(data)
+	if err != nil || len(pl) < 4 { // FIXME: isn't length checked inside quic.ReadCryptoPayload? Also, what about error handling?
+		s.invalidCount++
+		return nil, s.invalidCount >= quicInvalidCountThreshold
+	}
+
+	if pl[0] != internal.TypeClientHello {
+		s.invalidCount++
+		return nil, s.invalidCount >= quicInvalidCountThreshold
+	}
+
+	chLen := int(pl[1])<<16 | int(pl[2])<<8 | int(pl[3])
+	if chLen < minDataSize {
+		s.invalidCount++
+		return nil, s.invalidCount >= quicInvalidCountThreshold
+	}
+
+	m := internal.ParseTLSClientHelloMsgData(&utils.ByteBuffer{Buf: pl[4:]})
+	if m == nil {
+		s.invalidCount++
+		return nil, s.invalidCount >= quicInvalidCountThreshold
+	}
+
+	return &analyzer.PropUpdate{
+		Type: analyzer.PropUpdateMerge,
+		M:    analyzer.PropMap{"req": m},
+	}, true
+}
+
+func (s *quicStream) Close(limited bool) *analyzer.PropUpdate {
+	return nil
+}