Function lookupAndConnectMultiple

lib/net.js:1658–1771

(
  self, async_id_symbol, lookup, host, options, dnsopts, port, localAddress, localPort, timeout,
)

}

function lookupAndConnectMultiple(
  self, async_id_symbol, lookup, host, options, dnsopts, port, localAddress, localPort, timeout,
) {
  defaultTriggerAsyncIdScope(self[async_id_symbol], function emitLookup() {
    lookup(host, dnsopts, function emitLookup(err, addresses) {
      // It's possible we were destroyed while looking this up.
      // XXX it would be great if we could cancel the promise returned by
      // the look up.
      if (!self.connecting) {
        return;
      } else if (err) {
        self.emit('lookup', err, undefined, undefined, host);

        // net.createConnection() creates a net.Socket object and immediately
        // calls net.Socket.connect() on it (that's us). There are no event
        // listeners registered yet so defer the error event to the next tick.
        process.nextTick(connectErrorNT, self, err);
        return;
      }

      // Filter addresses by only keeping the one which are either IPv4 or IPV6.
      // The first valid address determines which group has preference on the
      // alternate family sorting which happens later.
      const validAddresses = [[], []];
      const validIps = [[], []];
      let destinations;
      for (let i = 0, l = addresses.length; i < l; i++) {
        const address = addresses[i];
        const { address: ip, family: addressType } = address;
        self.emit('lookup', err, ip, addressType, host);
        // It's possible we were destroyed while looking this up.
        if (!self.connecting) {
          return;
        }
        if (isIP(ip) && (addressType === 4 || addressType === 6)) {
          destinations ||= addressType === 6 ? { 6: 0, 4: 1 } : { 4: 0, 6: 1 };

          const destination = destinations[addressType];

          // Only try an address once
          if (!ArrayPrototypeIncludes(validIps[destination], ip)) {
            ArrayPrototypePush(validAddresses[destination], address);
            ArrayPrototypePush(validIps[destination], ip);
          }
        }
      }


      // When no AAAA or A records are available, fail on the first one
      if (!validAddresses[0].length && !validAddresses[1].length) {
        const { address: firstIp, family: firstAddressType } = addresses[0];

        if (!isIP(firstIp)) {
          err = new ERR_INVALID_IP_ADDRESS(firstIp);
          process.nextTick(connectErrorNT, self, err);
        } else if (firstAddressType !== 4 && firstAddressType !== 6) {
          err = new ERR_INVALID_ADDRESS_FAMILY(firstAddressType,
                                               options.host,