90 lines
2.2 KiB
JavaScript
90 lines
2.2 KiB
JavaScript
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'use strict';
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var dnsjs = require('dns-suite');
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var crypto = require('crypto');
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var dgram = require('dgram');
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function request(queryAb, opts) {
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var handlers = {};
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var server = dgram.createSocket({
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type: 'udp4'
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, reuseAddr: true
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});
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handlers.onError = function (err) {
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if (opts.onError) { opts.onError(err); }
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server.close();
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};
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handlers.onMessage = function (bin) {
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if (!opts.mdns) {
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server.close();
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}
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if (opts.onMessage) { opts.onMessage(bin); }
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};
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handlers.onListening = function () {
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/*jshint validthis:true*/
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var server = this;
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var nameservers;
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var index;
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server.nameserver = opts.nameserver;
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if (!server.nameserver) {
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nameservers = require('dns').getServers();
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index = crypto.randomBytes(2).readUInt16BE(0) % nameservers.length;
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server.nameserver = nameservers[index];
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}
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if (opts.mdns || '224.0.0.251' === opts.nameserver) {
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server.setBroadcast(true);
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server.addMembership(opts.nameserver);
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}
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if (opts.onListening) { opts.onListening.apply(server); }
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server.send(Buffer.from(queryAb), opts.port, server.nameserver, function () {
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if (opts.onSent) { opts.onSent({ port: opts.port, nameserver: server.nameserver }); }
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});
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};
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server.on('error', handlers.onError);
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server.on('message', handlers.onMessage);
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server.on('listening', handlers.onListening);
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// 0 dns request
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// 53 dns server
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// 5353 mdns
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if (opts.mdns) {
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server.bind(opts.port /*5353*/);
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setTimeout(function () {
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server.close();
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}, opts.timeout || (5 * 1000));
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}
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else {
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server.bind(0);
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}
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}
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function requestJson(query, opts) {
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var queryAb = dnsjs.DNSPacket.write(query);
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var options = {
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onError: opts.onError
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, onMessage: function (nb) {
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var packet = dnsjs.DNSPacket.parse(nb.buffer.slice(nb.byteOffset, nb.byteOffset + nb.byteLength));
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opts.onMessage(packet);
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}
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, onListening: opts.onListening
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, onSent: opts.onSent
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, mdns: opts.mdns
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, nameserver: opts.nameserver
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, port: opts.port
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, timeout: opts.timeout
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};
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return request(queryAb, options);
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}
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module.exports.request = request;
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module.exports.requestJson = requestJson;
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