advlib-esp
Version:
Wireless advertising packet decoding library for EnOcean Alliance devices via the EnOcean Serial Protocol (ESP). We believe in an open Internet of Things.
147 lines (120 loc) • 4.77 kB
JavaScript
/**
* Copyright reelyActive 2022-2024
* We believe in an open Internet of Things
*/
const header = require('./header');
const radioERP1 = require('./radioerp1');
const utils = require('./utils');
const MIN_PACKET_LENGTH_BYTES = 8;
const MIN_ERP1_PAYLOAD_LENGTH_BYTES = 6;
const SYNC_BYTE = 0x55;
const CRC_TABLE = [
0x00, 0x07, 0x0e, 0x09, 0x1c, 0x1b, 0x12, 0x15,
0x38, 0x3f, 0x36, 0x31, 0x24, 0x23, 0x2a, 0x2d,
0x70, 0x77, 0x7e, 0x79, 0x6c, 0x6b, 0x62, 0x65,
0x48, 0x4f, 0x46, 0x41, 0x54, 0x53, 0x5a, 0x5d,
0xe0, 0xe7, 0xee, 0xe9, 0xfc, 0xfb, 0xf2, 0xf5,
0xd8, 0xdf, 0xd6, 0xd1, 0xc4, 0xc3, 0xca, 0xcd,
0x90, 0x97, 0x9e, 0x99, 0x8c, 0x8b, 0x82, 0x85,
0xa8, 0xaf, 0xa6, 0xa1, 0xb4, 0xb3, 0xba, 0xbd,
0xc7, 0xc0, 0xc9, 0xce, 0xdb, 0xdc, 0xd5, 0xd2,
0xff, 0xf8, 0xf1, 0xf6, 0xe3, 0xe4, 0xed, 0xea,
0xb7, 0xb0, 0xb9, 0xbe, 0xab, 0xac, 0xa5, 0xa2,
0x8f, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9d, 0x9a,
0x27, 0x20, 0x29, 0x2e, 0x3b, 0x3c, 0x35, 0x32,
0x1f, 0x18, 0x11, 0x16, 0x03, 0x04, 0x0d, 0x0a,
0x57, 0x50, 0x59, 0x5e, 0x4b, 0x4c, 0x45, 0x42,
0x6f, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7d, 0x7a,
0x89, 0x8e, 0x87, 0x80, 0x95, 0x92, 0x9b, 0x9c,
0xb1, 0xb6, 0xbf, 0xb8, 0xad, 0xaa, 0xa3, 0xa4,
0xf9, 0xfe, 0xf7, 0xf0, 0xe5, 0xe2, 0xeb, 0xec,
0xc1, 0xc6, 0xcf, 0xc8, 0xdd, 0xda, 0xd3, 0xd4,
0x69, 0x6e, 0x67, 0x60, 0x75, 0x72, 0x7b, 0x7c,
0x51, 0x56, 0x5f, 0x58, 0x4d, 0x4a, 0x43, 0x44,
0x19, 0x1e, 0x17, 0x10, 0x05, 0x02, 0x0b, 0x0c,
0x21, 0x26, 0x2f, 0x28, 0x3d, 0x3a, 0x33, 0x34,
0x4e, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5c, 0x5b,
0x76, 0x71, 0x78, 0x7f, 0x6A, 0x6d, 0x64, 0x63,
0x3e, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2c, 0x2b,
0x06, 0x01, 0x08, 0x0f, 0x1a, 0x1d, 0x14, 0x13,
0xae, 0xa9, 0xa0, 0xa7, 0xb2, 0xb5, 0xbc, 0xbb,
0x96, 0x91, 0x98, 0x9f, 0x8a, 0x8D, 0x84, 0x83,
0xde, 0xd9, 0xd0, 0xd7, 0xc2, 0xc5, 0xcc, 0xcb,
0xe6, 0xe1, 0xe8, 0xef, 0xfa, 0xfd, 0xf4, 0xf3
];
/**
* Process a raw EnOcean Serial Protocol packet into semantically meaningful
* information.
* @param {Object} data The raw ESP packet as a hexadecimal-string or Buffer.
* @param {Array} libraries Optional ordered list of processing libraries.
* @param {Object} options Optional processing options.
* @return {Object} The processed packet as JSON.
*/
function process(data, libraries, options) {
options = options || {};
let buf = utils.convertToBuffer(data);
let processedPacket = {};
let isERP1PayloadOnly = (options.isERP1PayloadOnly === true);
if((buf === null) ||
(isERP1PayloadOnly && (buf.length < MIN_ERP1_PAYLOAD_LENGTH_BYTES)) ||
(buf.length < MIN_PACKET_LENGTH_BYTES)) {
return null;
}
if(isERP1PayloadOnly) {
processedPacket = radioERP1.process(data, libraries, options);
if(!processedPacket.hasOwnProperty('uri')) {
processedPacket.uri =
'https://sniffypedia.org/Organization/EnOcean_Alliance/';
}
return processedPacket;
}
// Abort if any of the SYNC byte, CRC8H or CRC8D are invalid
if((buf.readUInt8(0) !== SYNC_BYTE) || !isValidCRC(buf)) {
return null;
}
let headerProperties = header.process(buf.subarray(1, 5));
let dataBuf = buf.subarray(6, 6 + headerProperties.dataLength);
let includeProtocolOverhead = (options.ignoreProtocolOverhead !== true);
if(includeProtocolOverhead) {
Object.assign(processedPacket, headerProperties);
}
// Process the packet based on its type
switch(headerProperties.type) {
case 'RADIO_ERP1':
let telegramProperties = radioERP1.process(dataBuf, libraries, options);
Object.assign(processedPacket, telegramProperties);
break;
}
if(!processedPacket.hasOwnProperty('uri')) {
processedPacket.uri =
'https://sniffypedia.org/Organization/EnOcean_Alliance/';
}
return processedPacket;
}
/**
* Check that the CRC8H and CRC8D are both valid.
* @param {Buffer} packet The raw ESP packet.
* @return {boolean} Whether both are valid or not.
*/
function isValidCRC(packet) {
let crc8h = packet.readUInt8(5);
let crc8d = packet.readUInt8(packet.length - 1);
let headerBytes = packet.subarray(1, 5);
let dataBytes = packet.subarray(6, packet.length - 1);
return (crc8h === calculateCRC(headerBytes)) &&
(crc8d === calculateCRC(dataBytes));
}
/**
* Calculate the expected CRC based on the given bytes.
* @param {Buffer} bytes The packet bytes on which to calculate the CRC.
* @return {Number} The expected CRC.
*/
function calculateCRC(bytes) {
let crc = 0;
for(let cByte = 0; cByte < bytes.length; cByte++) {
crc = CRC_TABLE[(crc ^ bytes.readUInt8(cByte))];
}
return crc;
}
module.exports.process = process;
module.exports.header = header;