[split] admin login

Hello every one,
I am new here . I need some help
I have developed a project in codeigniter but I have Admin Auth Problem
I have authenticate the admin controller but Classes of admin controller are still accessible from url
I want a function which check for admin login and grant access to controller and its classes
Which function i should use
Like laravel provide middle-ware
CodeIgniter .........????
Plz Guide me ...