Sending data array when redirected to control panel

Code:
class Auth extends CI_Controller

{

function __construct()

{

    parent::__construct();



    $this->load->helper(array('form', 'url'));

    $this->load->library('form_validation');

    $this->load->library('security');

    $this->load->library('tank_auth');

    $this->lang->load('tank_auth');   



    if ($this->tank_auth->is_logged_in()) {

        redirect('/cpanel/');

    } else {

        redirect('/auth/login/');

    }      

}



function index()

{



}



/**

 * Login user on the site

 *

 * @return void

 */

function login()

{

    if ($this->tank_auth->is_logged_in()) {                                 // logged in

        redirect('/cpanel');



    } elseif ($this->tank_auth->is_logged_in(FALSE)) {                      // logged in, not activated

        redirect('/auth/send_again/');



    } else {

        $data['login_by_username'] = ($this->config->item('login_by_username', 'tank_auth') AND

                $this->config->item('use_username', 'tank_auth'));

        $data['login_by_email'] = $this->config->item('login_by_email', 'tank_auth');



        $this->form_validation->set_rules('login', 'Login', 'trim|required|xss_clean');

        $this->form_validation->set_rules('password', 'Password', 'trim|required|xss_clean');

        $this->form_validation->set_rules('remember', 'Remember me', 'integer');



        // Get login for counting attempts to login

        if ($this->config->item('login_count_attempts', 'tank_auth') AND

                ($login = $this->input->post('login'))) {

            $login = $this->security->xss_clean($login);

        } else {

            $login = '';

        }



        $data['errors'] = array();



        if ($this->form_validation->run()) {                                // validation ok

            if ($this->tank_auth->login(

                    $this->form_validation->set_value('login'),

                    $this->form_validation->set_value('password'),

                    $this->form_validation->set_value('remember'),

                    $data['login_by_username'],

                    $data['login_by_email'])) {                             // success

                redirect('/cpanel');



            } else {

                $errors = $this->tank_auth->get_error_message();

                if (isset($errors['banned'])) {                             // banned user

                    $this->_show_message($this->lang->line('auth_message_banned').' '.$errors['banned']);



                } elseif (isset($errors['not_activated'])) {                // not activated user

                    redirect('/auth/send_again/');



                } else {                                                    // fail

                    foreach ($errors as $k => $v)   $data['errors'][$k] = $this->lang->line($v);

                }

            }

        }

        $this->template->set_layout('default')->enable_parser(false);

        $this->template->build('auth/login_form', $data);

    }

}