ojousima.ruuvi_endpoints.ts/lib/ojousima_endpoint_fe.js

Experiments with RuuviTags and TS

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.dffeunencrypter = exports.dffeparser = void 0;
var aes_js_1 = require("aes-js");
var ruuvitagbroadcast_1 = require("./ruuvitagbroadcast");
var dataFormatStart = 0;
var dataFormatEnd = dataFormatStart + 1;
var versionStart = dataFormatEnd;
var versionEnd = versionStart + 1;
var versionInvalid = 255;
var addressStart = versionEnd;
var addressEnd = addressStart + 6;
var addressInvalid = 0xffffffffffff;
var humidityStart = addressEnd;
var humidityEnd = humidityStart + 1;
var humidityInvalid = 255;
var temperatureStart = humidityEnd;
var temperatureEnd = temperatureStart + 2;
var temperatureInvalid = -32768;
var pressureStart = temperatureEnd;
var pressureEnd = pressureStart + 2;
var pressureInvalid = 65535;
var batteryStart = pressureEnd;
var batteryEnd = batteryStart + 2;
var sequenceStart = batteryEnd;
var sequenceEnd = sequenceStart + 2;
var sequenceInvalid = 0xffff;
/*
 * @brief Parse FE data
 *
 * Throws error if header byte is not @c 0xFE or version byte is not @c 0x02
 *
 * @param data complete manufacturer data to be parsed, starting from header byte
 * @return Ruuvi data payload
 */
var dffeparser = function (data) {
    if (data.length < addressEnd - 1 || 0xfe !== data[0]) {
        throw new Error('Not DF5 data');
    }
    if (0x02 !== data[versionStart]) {
        throw new Error('Unsupported version ' + data[versionStart].toString(16));
    }
    var robject = new ruuvitagbroadcast_1.RuuviTagBroadcast();
    robject.dataFormat = data[dataFormatStart];
    var humidity = data[humidityStart];
    humidity /= 2; // scale
    robject.humidityRh = humidity;
    var temperatureBytes = data.slice(temperatureStart, temperatureEnd);
    var temperature = temperatureBytes[0]; // Full degrees
    temperature += temperatureBytes[1] / 100.0; // Decimals
    if (temperature > 128) {
        // Ruuvi format, sign bit + value
        temperature = temperature - 128;
        temperature = 0 - temperature;
    }
    robject.temperatureC = temperature;
    var pressureBytes = data.slice(pressureStart, pressureEnd); // uint16_t pascals
    var pressure = pressureBytes[0] * 256 + pressureBytes[1];
    pressure += 50000; // Ruuvi format
    robject.pressurePa = pressure;
    var batteryBytes = data.slice(batteryStart, batteryEnd); // millivolts
    var battery = batteryBytes[0] * 256 + batteryBytes[1];
    robject.batteryVoltageV = battery / 1000.0;
    var sequenceBytes = data.slice(sequenceStart, sequenceEnd);
    var sequence = sequenceBytes[0] * 256 + sequenceBytes[1];
    robject.measurementSequence = sequenceInvalid === sequence ? null : sequence;
    var addressBytes = data.slice(addressStart, addressEnd);
    // Sorry, but lint says so.
    var address = addressBytes[0] * 256 * 256 * 256 * 256 * 256 +
        addressBytes[1] * 256 * 256 * 256 * 256 +
        addressBytes[2] * 256 * 256 * 256 +
        addressBytes[3] * 256 * 256 +
        addressBytes[4] * 256 +
        addressBytes[5];
    robject.mac = addressInvalid === address ? null : address;
    return robject;
};
exports.dffeparser = dffeparser;
/*
 * @brief Unencrypt data with the basepassword and unique password.
 *
 * For example data version 2 has default password of "ruuvi.com\0" + device mac.
 * Convert ASCII (NOT UTF-8!) string of "ruuvi.com\0" to Uint8Array and use it as a basepw
 * Add device mac as unique pw. Returns complete data in unencrypted form as Uint8Array
 *
 * @param data complete manufacturer data to be unencrypted, starting from header byte
 * @param basepw: Base password used in encryption
 * @param unitpw: Unit-specific password used in encryption.
 * @return unencrypted FE data.
 * @warning Be careful when converting strings to Uint8Array to avoid UTF-8 encoded values.
 */
var dffeunencrypter = function (data, basepw, unitpw) {
    if (16 !== basepw.length + unitpw.length) {
        throw new Error('Invalid base+unit password length. Expected 16, got ' + (basepw.length + unitpw.length).toString());
    }
    var key = new Uint8Array(basepw.length + unitpw.length);
    key.set(basepw);
    key.set(unitpw, basepw.length);
    var aesEcb = new aes_js_1.ModeOfOperation.ecb(key);
    // All fe data starts with header + version, followed by encrypted 16-byte payload
    var encryptedBytes = data.subarray(2, 2 + 16);
    // Since electronic codebook does not store state, we can
    // reuse the same instance.
    var decryptedBytes = aesEcb.decrypt(encryptedBytes);
    return decryptedBytes;
};
exports.dffeunencrypter = dffeunencrypter;