Lukas Scheuerle (Plagiatus)
77 lines
2.4 KiB
JavaScript
77 lines
2.4 KiB
JavaScript
/**
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* Functions for managing packets used by the RCON protocol
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*/
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class Packet {
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/**
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* Generate a unique max 32 bit ID integer
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* @return {Number} Generated ID
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*/
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static id () {
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return Number.parseInt(Math.random().toString(2).substring(2, 32), 2);
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}
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/**
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* Create a new packet buffer with given ID, type and payload
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* @param {Number} id A unique max 32 bit client generated request ID
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* @param {[type]} type Type of the packet
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* @param {String} payload Data to be sent encoded in 'ASCII'
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* @return {Buffer} Created packet
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*/
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static write (id, type, payload) {
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// Length of payload in bytes when encoded in ASCII
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const length = Buffer.byteLength(payload, 'ascii');
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// 14 bytes for the length, ID, type and 2-byte padding
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const buffer = Buffer.allocUnsafe(14 + length);
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// Offsets are hardcoded for speed
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buffer.writeInt32LE(10 + length, 0); // Length
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buffer.writeInt32LE(id, 4); // Request ID
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buffer.writeInt32LE(type, 8); // Type
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buffer.write(payload, 12, 'ascii'); // Payload
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buffer.writeInt16LE(0, 12 + length); // Two null bytes of padding
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return buffer;
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}
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/**
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* Parse the given packet into a JSON object
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* @param {Buffer} packet
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* @return {Object} Parsed packet
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*/
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static read (packet) {
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// Length of the rest of the packet
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const length = packet.readInt32LE(0);
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// Check if we have a valid packet with 2 null bytes of padding in the end
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if (packet.length === 4 + length && !packet.readInt16LE(packet.length - 2)) {
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// Offsets are hardcoded for speed
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return {
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length: length,
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id: packet.readInt32LE(4),
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type: packet.readInt32LE(8),
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payload: packet.toString('ascii', 12, packet.length - 2)
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};
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} else {
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throw new Error(`Invalid packet! [${packet}]`);
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}
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}
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}
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/**
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* RCON packet type Integers understood by the Mineccraft Server
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* https://wiki.vg/RCON#Packets
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* @type {Object}
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*/
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Packet.type = {
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AUTH: 3,
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AUTH_RES: 2,
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COMMAND: 2,
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COMMAND_RES: 0,
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// Invalid type that can be used to detect when the full response has been received
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COMMAND_END: 255
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};
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/**
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* Predefined responses the Minecraft Server can send
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* @type {Object}
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*/
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Packet.payload = {
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// Response the server sends after receiving a packet with above invalid type
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COMMAND_END: `Unknown request ${Packet.type['COMMAND_END'].toString(16)}`
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};
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module.exports = Packet;
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