Freeradius username, password + MAC address auth

Hello. I am running freeradius 2.1.7 server on my Centos. I am using mysql database. everything works ok! I am using username password method for auth, but now i want to add mac address auth method too. I want Radius server checks username, password and MAC addresses at the same time when the user authenticate. How can i do this? I am using mikrotik as nas.