func()

in pcap-cli/internal/transformer/json_tls_translator.go [29:106]

• 57 lines of code
• 6 McCabe index (conditional complexity)

func (t *JSONPcapTranslator) translateTLSLayer_decodeClientHello(hs cryptobyte.String, TLS *gabs.Container) {
	ch := make(map[string]interface{}, 4)

	ch["type"] = "ClientHello"

	var clientHello cryptobyte.String
	hs.ReadUint24LengthPrefixed(&clientHello)

	var legacyVersion uint16
	clientHello.ReadUint16(&legacyVersion)
	ch["legacy_version"] = layers.TLSVersion(legacyVersion).String()

	// var random []byte
	// clientHello.ReadBytes(&random, 32)
	// ch.Set(random, "random")

	// var legacySessionID []byte
	// clientHello.ReadUint8LengthPrefixed((*cryptobyte.String)(&legacySessionID))
	// ch.Set(legacySessionID, "legacy_session_id")

	clientHello.Skip(33)

	var ciphersuitesBytes cryptobyte.String
	clientHello.ReadUint16LengthPrefixed(&ciphersuitesBytes)
	var ciphers []uint16
	for !ciphersuitesBytes.Empty() {
		var ciphersuite uint16
		ciphersuitesBytes.ReadUint16(&ciphersuite)
		ciphers = append(ciphers, ciphersuite)
	}
	ch["ciphers"] = ciphers

	var legacyCompressionMethods []uint8
	clientHello.ReadUint8LengthPrefixed((*cryptobyte.String)(&legacyCompressionMethods))
	ch["legacy_compression_methods"] = legacyCompressionMethods

	var extensionsBytes cryptobyte.String
	clientHello.ReadUint16LengthPrefixed(&extensionsBytes)

	var extensions []map[string]interface{}
	for !extensionsBytes.Empty() {
		var extType uint16
		extensionsBytes.ReadUint16(&extType)

		ext := make(map[string]interface{}, 3)
		ext["type"] = extType

		var extData cryptobyte.String
		extensionsBytes.ReadUint16LengthPrefixed(&extData)

		switch extType {
		default:
			ext["name"] = "UNKNOWN"
		case 0: // Server Name
			ext["name"] = "server_name"
			extData.Skip(5)
			ext["data"] = string(extData)
		case 16: // ALPN
			ext["name"] = "application_layer_protocol_negotiation"
			var alpnData cryptobyte.String
			extData.ReadUint16LengthPrefixed(&alpnData)
			var data []string
			for !alpnData.Empty() {
				var length uint8
				alpnData.ReadUint8(&length)
				var proto []byte
				alpnData.ReadBytes(&proto, int(length))
				data = append(data, string(proto))
			}
			ext["data"] = data
		}

		extensions = append(extensions, ext)
	}
	ch["extensions"] = extensions

	TLS.SetP(ch, "data.client_hello")
}