MAC Auth tied to user

[johan firdianto]

anyone here have experience to implement
authorization and accounting from mac to user ?
For example:
User john is tied to mac aa-bb-cc-dd-ee-ff.
every authorization comes from this mac,
radius will check session for user john.
and do accounting for user john also.
So, every packet auth/acct come from NAS, username 'mac'  will be replaced
to 'user' subsquent process.
i think unlang is the solution.
anyone here could give us suggest/idea ?
Cheers.

Johan