smp_crc_t
(offsetof(smp_request_frame_t, srf_data[0]) + sizeof (smp_crc_t))
(offsetof(smp_response_frame_t, srf_data[0]) + sizeof (smp_crc_t))
(ap->sa_request_data_off + sizeof (smp_crc_t));
(offsetof(smp_request_frame_t, srf_data[0]) + sizeof (smp_crc_t))
(offsetof(smp_response_frame_t, srf_data[0]) + sizeof (smp_crc_t))