counter.errors = subul(new_counter.errors, old_counter.errors);
counter.send_count = subul(new_counter.send_count, old_counter.send_count);
counter.recv_count = subul(new_counter.recv_count, old_counter.recv_count);
counter.errors = subul(new_counter.errors, old_counter.errors);
counter.send_count = subul(new_counter.send_count, old_counter.send_count);
counter.recv_count = subul(new_counter.recv_count, old_counter.recv_count);