XTLS/Xray-core · error

unknown type

Error message

unknown type

What it means

PraseByteSlice (infra/conf/transport_finalmask.go:63) decodes a raw JSON "packet" value according to the item's "type" field. Only ""/"array" (JSON byte array), "str", "hex", and "base64" are recognized; any other type string returns "unknown type" and the transport config fails to build.

Source

Thrown at infra/conf/transport_finalmask.go:63

		var str string
		if err := json.Unmarshal(data, &str); err != nil {
			return nil, err
		}
		return []byte(str), nil
	case "hex":
		var str string
		if err := json.Unmarshal(data, &str); err != nil {
			return nil, err
		}
		return hex.DecodeString(str)
	case "base64":
		var str string
		if err := json.Unmarshal(data, &str); err != nil {
			return nil, err
		}
		return base64.StdEncoding.DecodeString(str)
	default:
		return nil, errors.New("unknown type")
	}
}

var (
	customVarNamePattern = regexp.MustCompile(`^[A-Za-z_][A-Za-z0-9_]*$`)

	tcpmaskLoader = NewJSONConfigLoader(ConfigCreatorCache{
		"header-custom": func() interface{} { return new(HeaderCustomTCP) },
		"fragment":      func() interface{} { return new(FragmentMask) },
		"sudoku":        func() interface{} { return new(Sudoku) },
		"xmc":           func() interface{} { return new(XMC) },
	}, "type", "settings")

	udpmaskLoader = NewJSONConfigLoader(ConfigCreatorCache{
		"header-custom": func() interface{} { return new(HeaderCustomUDP) },
		"mkcp-legacy":   func() interface{} { return new(MkcpLegacy) },
		"noise":         func() interface{} { return new(NoiseMask) },
		"salamander":    func() interface{} { return new(Salamander) },

View on GitHub (pinned to 7d214f8b09)

Solutions

1. Set type to one of "array" (or omit), "str", "hex", "base64"
2. Match payload to type: str/hex/base64 take a JSON string; array takes [1,2,3]
3. Omit type entirely and supply the packet as a JSON byte array

Example fix

// before
{ "type": "ascii", "packet": "GET / HTTP/1.1\r\n" }
// after
{ "type": "str", "packet": "GET / HTTP/1.1\r\n" }

const okTypes = new Set(['', 'array', 'str', 'hex', 'base64']);
for (const item of [...(mask.client??[]), ...(mask.server??[]), ...(mask.noise??[])]) {
  if (item.packet && item.type && !okTypes.has(item.type.toLowerCase())) throw new Error(`unknown packet type: ${item.type}`);
  if (['str','hex','base64'].includes((item.type??'').toLowerCase()) && typeof item.packet !== 'string') throw new Error('str/hex/base64 packets must be JSON strings');
  if ((item.type??'') === '' || item.type === 'array') { if (!Array.isArray(item.packet)) throw new Error('array packets must be JSON byte arrays'); }
}

const isPacketType = (t: string) => ['','array','str','hex','base64'].includes(t.toLowerCase());

When it happens

Trigger: A TCPItem/UDPItem/NoiseItem with "type":"utf8" (or "b64", "Hex", any misspelling) and a non-empty packet. Note strings.ToLower is applied, so "Hex" works but "hexadecimal" does not. Empty type with a JSON array [104,105] is the default and valid.

Common situations: Hand-writing header-custom/noise masks and guessing the type vocabulary; copying examples from third-party clients that use different type names; typos like "base64 " with trailing whitespace.

Related errors

• invalid fakedns config
• failed to parse Socks user
• failed to parse socks account
• gecko: invalid min/max packet size
• invalid scheme + u.Scheme

AI-assisted analysis of XTLS/Xray-core@7d214f8b09 (2026-08-15). Data as JSON: /api/errors/8fb50d00c1970bc9. Report an issue: GitHub.