IP_FLAG_RECEIVE_DEST_ADDR
(protocol->flags & IP_FLAG_RECEIVE_DEST_ADDR) != 0);
protocol->flags |= IP_FLAG_RECEIVE_DEST_ADDR;
protocol->flags &= ~IP_FLAG_RECEIVE_DEST_ADDR;
if ((((ipv4_protocol*)protocol)->flags & IP_FLAG_RECEIVE_DEST_ADDR) != 0) {