Freeradius as DHCP server with option 82

Hi All, I am a newbie trying to configure freeradius as DHCP server to authenticated DHCP requests with option 82 and assign IP addresses. I am not sure how to parse the DHCP option 82 from request validate that value and then return the DHCP offer if the option 82 has valid value. I couldnt find any documentation on that. Any help from you guys or any documentation for that will be really helpful. Regards, Brijesh