79 lines
2.4 KiB
JavaScript
79 lines
2.4 KiB
JavaScript
const dns = require('dns')
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const logger = require('./logger')
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const { TimeTracker } = require('./time')
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const config = require('../config')
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const SKIP_SRV_TIMEOUT = config.skipSrvTimeout || 60 * 60 * 1000
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class DNSResolver {
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constructor (ip, port) {
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this._ip = ip
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this._port = port
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}
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_skipSrv () {
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this._skipSrvUntil = TimeTracker.getEpochMillis() + SKIP_SRV_TIMEOUT
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}
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_isSkipSrv () {
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return this._skipSrvUntil && TimeTracker.getEpochMillis() <= this._skipSrvUntil
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}
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resolve (callback) {
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if (this._isSkipSrv()) {
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callback(this._ip, this._port, config.rates.connectTimeout)
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return
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}
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const startTime = TimeTracker.getEpochMillis()
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let callbackFired = false
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const fireCallback = (ip, port) => {
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if (!callbackFired) {
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callbackFired = true
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// Send currentTime - startTime to provide remaining connectionTime allowance
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const remainingTime = config.rates.connectTimeout - (TimeTracker.getEpochMillis() - startTime)
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callback(ip || this._ip, port || this._port, remainingTime)
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}
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}
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const timeoutCallback = setTimeout(fireCallback, config.rates.connectTimeout)
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dns.resolveSrv('_minecraft._tcp.' + this._ip, (err, records) => {
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// Cancel the timeout handler if not already fired
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if (!callbackFired) {
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clearTimeout(timeoutCallback)
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}
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// Test if the error indicates a miss, or if the records returned are empty
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if ((err && (err.code === 'ENOTFOUND' || err.code === 'ENODATA')) || !records || records.length === 0) {
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// Compare config.skipSrvTimeout directly since SKIP_SRV_TIMEOUT has an or'd value
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// isSkipSrvTimeoutDisabled == whether the config has a valid skipSrvTimeout value set
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const isSkipSrvTimeoutDisabled = typeof config.skipSrvTimeout === 'number' && config.skipSrvTimeout === 0
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// Only activate _skipSrv if the skipSrvTimeout value is either NaN or > 0
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// 0 represents a disabled flag
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if (!this._isSkipSrv() && !isSkipSrvTimeoutDisabled) {
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this._skipSrv()
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logger.log('warn', 'No SRV records were resolved for %s. Minetrack will skip attempting to resolve %s SRV records for %d minutes.', this._ip, this._ip, SKIP_SRV_TIMEOUT / (60 * 1000))
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}
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fireCallback()
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} else {
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// Only fires if !err && records.length > 0
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fireCallback(records[0].name, records[0].port)
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}
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})
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}
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}
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module.exports = DNSResolver
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