You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: start.go
    path of file: ./repos/openyurt/cmd/yurt-tunnel-server/app
    
    the code of the file until where you have to start completion: /*
Copyright 2020 The OpenYurt Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    h
    
func getTunnelServerIPsAndDNSNamesBeforeInformerSynced(clientset kubernetes.Interface, stopCh <-chan struct{}) ([]net.IP, []string, error) {
	var (
		ips      = []net.IP{}
		dnsNames = []string{}
		err      error
	)

	// the ips and dnsNames should be acquired through api-server at the first time, because the informer factory has not started yet.
	werr := wait.PollUntil(5*time.Second, func() (bool, error) {
		dnsNames, ips, err = serveraddr.GetYurttunelServerDNSandIP(clientset)
		if err != nil {
			klog.Errorf("failed to get yurt tunnel server dns and ip, %v", err)
			return false, err
		}

		// get clusterIP for tunnel server internal service
		svc, err := clientset.CoreV1().Services(constants.YurttunnelServerServiceNs).Get(context.Background(), constants.YurttunnelServerInternalServiceName, metav1.GetOptions{})
		if errors.IsNotFound(err) {
			// compatible with versions that not supported x-tunnel-server-internal-svc
			klog.Warningf("get service: %s not found", constants.YurttunnelServerInternalServiceName)
			return true, nil
		} else if err != nil {
			klog.Warningf("get service: %s err, %v", constants.YurttunnelServerInternalServiceName, err)
			return false, err
		}

		if svc.Spec.ClusterIP != "" && net.ParseIP(svc.Spec.ClusterIP) != nil {
			ips = append(ips, net.ParseIP(svc.Spec.ClusterIP))
			dnsNames = append(dnsNames, serveraddr.GetDefaultDomainsForSvc(svc.Namespace, svc.Name)...)
		}

		return true, nil
	}, stopCh)
	if werr != nil {
		return nil, nil, werr
	}
	return ips, dnsNames, nil
}