Fix IndexTLSServerName

common/tlsfragment/conn.go

@@ -45,7 +45,7 @@ func (c *Conn) Write(b []byte) (n int, err error) {
 		defer func() {
 			c.firstPacketWritten = true
 		}()
-		serverName := indexTLSServerName(b)
+		serverName := IndexTLSServerName(b)
 		if serverName != nil {
 			if c.splitPacket {
 				if c.tcpConn != nil {

common/tlsfragment/index.go

@@ -22,13 +22,13 @@ const (
 	tls13                   uint16 = 0x0304
 )
 
-type myServerName struct {
+type MyServerName struct {
 	Index      int
 	Length     int
 	ServerName string
 }
 
-func indexTLSServerName(payload []byte) *myServerName {
+func IndexTLSServerName(payload []byte) *MyServerName {
 	if len(payload) < recordLayerHeaderLen || payload[0] != contentType {
 		return nil
 	}
@@ -36,47 +36,48 @@ func indexTLSServerName(payload []byte) *myServerName {
 	if len(payload) < recordLayerHeaderLen+int(segmentLen) {
 		return nil
 	}
-	serverName := indexTLSServerNameFromHandshake(payload[recordLayerHeaderLen : recordLayerHeaderLen+int(segmentLen)])
+	serverName := indexTLSServerNameFromHandshake(payload[recordLayerHeaderLen:])
 	if serverName == nil {
 		return nil
 	}
-	serverName.Length += recordLayerHeaderLen
+	serverName.Index += recordLayerHeaderLen
 	return serverName
 }
 
-func indexTLSServerNameFromHandshake(hs []byte) *myServerName {
-	if len(hs) < handshakeHeaderLen+randomDataLen+sessionIDHeaderLen {
+func indexTLSServerNameFromHandshake(handshake []byte) *MyServerName {
+	if len(handshake) < handshakeHeaderLen+randomDataLen+sessionIDHeaderLen {
 		return nil
 	}
-	if hs[0] != handshakeType {
+	if handshake[0] != handshakeType {
 		return nil
 	}
-	handshakeLen := uint32(hs[1])<<16 | uint32(hs[2])<<8 | uint32(hs[3])
-	if len(hs[4:]) != int(handshakeLen) {
+	handshakeLen := uint32(handshake[1])<<16 | uint32(handshake[2])<<8 | uint32(handshake[3])
+	if len(handshake[4:]) != int(handshakeLen) {
 		return nil
 	}
-	tlsVersion := uint16(hs[4])<<8 | uint16(hs[5])
+	tlsVersion := uint16(handshake[4])<<8 | uint16(handshake[5])
 	if tlsVersion&tlsVersionBitmask != 0x0300 && tlsVersion != tls13 {
 		return nil
 	}
-	sessionIDLen := hs[38]
-	if len(hs) < handshakeHeaderLen+randomDataLen+sessionIDHeaderLen+int(sessionIDLen) {
+	sessionIDLen := handshake[38]
+	currentIndex := handshakeHeaderLen + randomDataLen + sessionIDHeaderLen + int(sessionIDLen)
+	if len(handshake) < currentIndex {
 		return nil
 	}
-	cs := hs[handshakeHeaderLen+randomDataLen+sessionIDHeaderLen+int(sessionIDLen):]
-	if len(cs) < cipherSuiteHeaderLen {
+	cipherSuites := handshake[currentIndex:]
+	if len(cipherSuites) < cipherSuiteHeaderLen {
 		return nil
 	}
-	csLen := uint16(cs[0])<<8 | uint16(cs[1])
-	if len(cs) < cipherSuiteHeaderLen+int(csLen)+compressMethodHeaderLen {
+	csLen := uint16(cipherSuites[0])<<8 | uint16(cipherSuites[1])
+	if len(cipherSuites) < cipherSuiteHeaderLen+int(csLen)+compressMethodHeaderLen {
 		return nil
 	}
-	compressMethodLen := uint16(cs[cipherSuiteHeaderLen+int(csLen)])
-	if len(cs) < cipherSuiteHeaderLen+int(csLen)+compressMethodHeaderLen+int(compressMethodLen) {
+	compressMethodLen := uint16(cipherSuites[cipherSuiteHeaderLen+int(csLen)])
+	currentIndex += cipherSuiteHeaderLen + int(csLen) + compressMethodHeaderLen + int(compressMethodLen)
+	if len(handshake) < currentIndex {
 		return nil
 	}
-	currentIndex := cipherSuiteHeaderLen + int(csLen) + compressMethodHeaderLen + int(compressMethodLen)
-	serverName := indexTLSServerNameFromExtensions(cs[currentIndex:])
+	serverName := indexTLSServerNameFromExtensions(handshake[currentIndex:])
 	if serverName == nil {
 		return nil
 	}
@@ -84,7 +85,7 @@ func indexTLSServerNameFromHandshake(hs []byte) *myServerName {
 	return serverName
 }
 
-func indexTLSServerNameFromExtensions(exs []byte) *myServerName {
+func indexTLSServerNameFromExtensions(exs []byte) *MyServerName {
 	if len(exs) == 0 {
 		return nil
 	}
@@ -118,7 +119,8 @@ func indexTLSServerNameFromExtensions(exs []byte) *myServerName {
 			}
 			sniLen := uint16(sex[3])<<8 | uint16(sex[4])
 			sex = sex[sniExtensionHeaderLen:]
-			return &myServerName{
+
+			return &MyServerName{
 				Index:      currentIndex + extensionHeaderLen + sniExtensionHeaderLen,
 				Length:     int(sniLen),
 				ServerName: string(sex),