index.js

const {
  TCPServer,
  UDPServer,
  DOHServer,
  createTCPServer,
  createUDPServer,
  createDOHServer,
  createServer,
} = require('./server');
const EventEmitter = require('events');

/**
 * [DNS description]
 * @docs https://tools.ietf.org/html/rfc1034
 * @docs https://tools.ietf.org/html/rfc1035
 */
class DNS extends EventEmitter {
  constructor(options) {
    super();
    Object.assign(this, {
      port             : 53,
      retries          : 3,
      timeout          : 3,
      recursive        : true,
      resolverProtocol : 'UDP',
      nameServers      : [
        '8.8.8.8',
        '114.114.114.114',
      ],
      rootServers: [
        'a', 'b', 'c', 'd', 'e', 'f',
        'g', 'h', 'i', 'j', 'k', 'l', 'm',
      ].map(x => `${x}.root-servers.net`),
    }, options);
  }

  /**
   * resolve
   * @param {*} domain
   * @param {*} type
   * @param {*} cls
   */
  resolve(domain, type = 'ANY', cls = DNS.Packet.CLASS.IN, options = {}) {
    const { port, nameServers, resolverProtocol = 'UDP' } = this;
    const createResolver = DNS[resolverProtocol + 'Client'];
    return Promise.race(nameServers.map(address => {
      const resolve = createResolver({ dns: address, port });
      return resolve(domain, type, cls, options);
    }));
  }

  resolveA(domain, clientIp) {
    return this.resolve(domain, 'A', undefined, clientIp);
  }

  resolveAAAA(domain) {
    return this.resolve(domain, 'AAAA');
  }

  resolveMX(domain) {
    return this.resolve(domain, 'MX');
  }

  resolveCNAME(domain) {
    return this.resolve(domain, 'CNAME');
  }

  resolvePTR(domain) {
    return this.resolve(domain, 'PTR');
  }

  resolveDNSKEY(domain) {
    return this.resolve(domain, 'DNSKEY');
  }

  resolveRRSIG(domain) {
    return this.resolve(domain, 'RRSIG');
  }
}

DNS.TCPServer = TCPServer;
DNS.UDPServer = UDPServer;
DNS.DOHServer = DOHServer;

DNS.createUDPServer = createUDPServer;
DNS.createTCPServer = createTCPServer;
DNS.createDOHServer = createDOHServer;
DNS.createServer = createServer;

DNS.TCPClient = require('./client/tcp');
DNS.DOHClient = require('./client/doh');
DNS.UDPClient = require('./client/udp');
DNS.GoogleClient = require('./client/google');

DNS.Packet = require('./packet');

module.exports = DNS;