Function createServerHandle

lib/net.js:2057–2113

(address, port, addressType, fd, flags)

// Returns handle if it can be created, or error code if it can't
function createServerHandle(address, port, addressType, fd, flags) {
  let err = 0;
  // Assign handle in listen, and clean up if bind or listen fails
  let handle;

  let isTCP = false;
  if (typeof fd === 'number' && fd >= 0) {
    try {
      handle = createHandle(fd, true);
    } catch (e) {
      // Not a fd we can listen on.  This will trigger an error.
      debug('listen invalid fd=%d:', fd, e.message);
      return UV_EINVAL;
    }

    err = handle.open(fd);
    if (err)
      return err;

    assert(!address && !port);
  } else if (port === -1 && addressType === -1) {
    handle = new Pipe(PipeConstants.SERVER);
    if (isWindows) {
      const instances = NumberParseInt(process.env.NODE_PENDING_PIPE_INSTANCES);
      if (!NumberIsNaN(instances)) {
        handle.setPendingInstances(instances);
      }
    }
  } else {
    handle = new TCP(TCPConstants.SERVER);
    isTCP = true;
  }

  if (address || port || isTCP) {
    debug('bind to', address || 'any');
    if (!address) {
      // Try binding to ipv6 first
      err = handle.bind6(DEFAULT_IPV6_ADDR, port, flags);
      if (err) {
        handle.close();
        // Fallback to ipv4
        return createServerHandle(DEFAULT_IPV4_ADDR, port, undefined, undefined, flags);
      }
    } else if (addressType === 6) {
      err = handle.bind6(address, port, flags);
    } else {
      err = handle.bind(address, port, flags);
    }
  }

  if (err) {
    handle.close();
    return err;
  }

  return handle;
}