xsk_pool_get_headroom
return xsk_pool_get_headroom(pool) <= 0xffff &&
xsk->headroom = xsk_pool_get_headroom(pool);
headroom = xsk_pool_get_headroom(rx_ring->r_vec->xsk_pool);
if (vi->hdr_len > xsk_pool_get_headroom(pool))
return xsk_pool_get_chunk_size(pool) - xsk_pool_get_headroom(pool);