Передача файла по udp

void MainWindow::send_file()
{
    quint8 part_count = 1;
    quint8 count = file_size / part_size;
    if (count < (file_size / part_size))
        count ++;
 
    QByteArray buffer;
    QByteArray array;
    QDataStream stream(&buffer,QIODevice::WriteOnly);
    stream.setVersion(QDataStream::Qt_5_8);
    stream << quint16(0) << quint8(0) << file_size << filename << count;
    stream.device()->seek(0);
    quint16 temp2 = buffer.size() - sizeof(quint16);
    stream << quint16(buffer.size() - sizeof(quint16));
    socket->writeDatagram(buffer, server_ip, server_port);
 
    QFile file(filename);
    file.open(QIODevice::ReadOnly);
 
    for (int part = 0; !(array = file.read(part_size)).isEmpty(); part+=part_size)
    {
        stream << quint16(0) << (quint8)part_count << array;
        stream.device()->seek(0);
        quint16 temp = buffer.size() - sizeof(quint16);
        stream << quint16(buffer.size() - sizeof(quint16));
        socket->writeDatagram(buffer, server_ip, server_port);
        ui->progressBar->setValue(part);
        buffer.clear();
        array.clear();
        part_count ++;
    }
}

void MainWindow::ready_read()
{
    QHostAddress sender_ip;
    quint16 sender_port;
    quint16 size;
    quint8 command;
    QByteArray buffer;
    QByteArray array;
    quint8 parts;
    quint8 part_count = 1;
 
    buffer.resize(socket->pendingDatagramSize());
    socket->readDatagram(buffer.data(), buffer.size(), &sender_ip, &sender_port);
 
    QDataStream stream(&buffer,QIODevice::ReadOnly);
    stream.setVersion(QDataStream::Qt_5_8);
    stream >> size >> command;
 
    switch (command) {
        case 0: {
            stream >> filesize >> filename >> parts;
            filename = "/home/tproo/Pictures/temp/" + QDir(filename).absolutePath();
            QFile file(filename);
            file.open(QIODevice::WriteOnly);
            file.close();
            ui->progressBar->setMaximum(filesize);
            break;
        }
        default: {
            part_count ++;
            stream >> array;
            QFile file(filename);
            file.open(QIODevice::Append);
            QDataStream file_stream(&file);
            file_stream << array;
            break;
        }
    }
}