Returns: Access code, FALSE on error.
After the Radius request has been constructed, it is sent by radius_send_request()
The radius_send_request() function sends the request and waits for a valid reply, retrying the defined servers in round-robin fashion as necessary. If a valid response is received, radius_send_request() returns the Radius code which specifies the type of the response. This will typically be RADIUS_ACCESS_ACCEPT, RADIUS_ACCESS_REJECT, or RADIUS_ACCESS_CHALLENGE. If no valid response is received, radius_send_request() returns FALSE.