netmap_mem_get_info
error = netmap_mem_get_info(nmd, &nmr->nr_memsize, &memflags);
error = netmap_mem_get_info(na->nm_mem, &nmr->nr_memsize, &memflags);
int netmap_mem_get_info(struct netmap_mem_d *, u_int *size, u_int *memflags);