Can not now to compil my prog, to use bpf_get_mad_fd_by_id for just beggining, because dont know enough how to do it. To compile kern prog a lot of examples, but userspace prog can not find... Can you help me with link how to do it? 

P.s. tried to make key size of struct 9 bytes, it does not set to device because of error, about indirect access to mem. I can make only with 4, 8, 12, 16....?