CAN socketCAN - how reliable is for file transfer - linux

Question

I want to send files (mp3 about 4MB each) to devices connected via CAN. I'm testing with Linux machine and ESP32. The problem is that not all data arrives to destination.
I'm sending from Linux machine using socketCAN and UCCB USB-CAN converter
https://www.tindie.com/products/lll7/can-usb-converter-uccb/ to ESP32, or between two ESP32.
When sending from PC Linux to ESP32, sometimes only 1/3 of mp3 file is saved, during sending I have candump slcan0 command running and it looks like all data is on the bus, but ESP32 does not see some frames.
When I send between two ESP32, for instance 4MB of data, receiving ESP32 gets around 3,98MB of data, some frames gets lost.
I'm using command "slcand -o -c -f -s8 /dev/ttyACM0 slcan0" to create slcan0 interface, although changing the speed with -s switch does not seem to work.
Am I missing something, or CAN is not suitable for such high speed, high load operations? I want to have 30 devices on canbus that receive around 1GB of data (mp3 files)
code below:
CanMgr::CanMgr(QObject *parent,LogModel *logModel):QObject(parent) {
this->logModel=logModel;
send_timer=new QTimer(this);
send_timer->setSingleShot(true);
send_timer->setInterval(1);
connect(send_timer,&QTimer::timeout,this,&CanMgr::processQueue);
}
void CanMgr::connectDevice() {
QString errorString;
m_canDevice = QCanBus::instance()->createDevice(m_pluginName,m_socketName,&errorString);
if (!m_canDevice) {
qDebug()<<QString("Error creating device '%1', reason: '%2'").arg(m_pluginName).arg(errorString);
return;
}
m_numberFramesWritten = 0;
connect(m_canDevice, &QCanBusDevice::errorOccurred, this, &CanMgr::processErrors);
connect(m_canDevice, &QCanBusDevice::framesReceived, this, &CanMgr::processReceivedFrames);
connect(m_canDevice, &QCanBusDevice::framesWritten, this, &CanMgr::processFramesWritten);
connect(m_canDevice, &QCanBusDevice::stateChanged,this, &CanMgr::stateChanged);
m_canDevice->setConfigurationParameter(QCanBusDevice::BitRateKey,"250000");
if (!m_canDevice->connectDevice()) {
qDebug()<<tr("Connection error: %1").arg(m_canDevice->errorString());
delete m_canDevice;
m_canDevice = nullptr;
} else {
QVariant bitRate = m_canDevice->configurationParameter(QCanBusDevice::BitRateKey);
if (bitRate.isValid()) {
qDebug()<<tr("Plugin: %1, connected to %2 at %3 kBit/s").arg(m_pluginName).arg(m_socketName).arg(bitRate.toInt() / 1000);
} else {
qDebug()<<tr("Plugin: %1, connected to %2").arg(m_pluginName).arg(m_socketName);
}
}
}
void CanMgr::sendFileContent(QByteArray data) {
quint32 frameId = 0;
quint32 dev_id=2;
quint32 cmd_id=0;
frameId=(dev_id<<16) | cmd_id;
m_canDevice->clear();
QByteArray size=Helper::byteArrFromInt((quint32)data.size(),8);
qDebug()<<"CanMgr::sendFileContent file size in bytes:"<<Helper::printHex(size);
QCanBusFrame frame = QCanBusFrame(frameId,size);
frame.setExtendedFrameFormat(true);
qDebug()<<"frame data:"<<frame.toString()<<" stat:"<<m_canDevice->state();
queue.append(frame);
frameId = 0;
dev_id=2;
cmd_id=1;
frameId=(dev_id<<16) | cmd_id;
for(int i=0;i<data.size();i+=8) {
QCanBusFrame frame = QCanBusFrame(frameId, data.mid(i,8));
frame.setExtendedFrameFormat(true);
queue.append(frame);
}
frameId = 0;
dev_id=2;
cmd_id=2;
frameId=(dev_id<<16) | cmd_id;
frame = QCanBusFrame(frameId, size);
frame.setExtendedFrameFormat(true);
queue.append(frame);
process_frame=false;
send_timer->start();
}
void CanMgr::processQueue() {
if(queue.isEmpty()) {
qDebug()<<"CanMgr::processQueu queue empty";
return;
}
if(process_frame) {
;
}
else {
curr_frame=queue.dequeue();
process_frame=true;
}
qDebug()<<"CanMgr::processQueue frame data:"<<curr_frame.toString()<<" towrite:"<<m_canDevice->framesToWrite()<<" left:"<<queue.count();
m_canDevice->writeFrame(curr_frame);
}
void CanMgr::processFramesWritten(qint64 count) {
qDebug()<<"CanMgr::processFramesWritten count:"<<count;
process_frame=false;
this->processQueue();
}
QString CanMgr::processErrors(QCanBusDevice::CanBusError error) const
{
QString err_str;
switch (error) {
case QCanBusDevice::ReadError:
case QCanBusDevice::WriteError:
case QCanBusDevice::ConnectionError:
case QCanBusDevice::ConfigurationError:
case QCanBusDevice::UnknownError:
err_str= m_canDevice->errorString();
qDebug()<<"Error:"<<err_str;
send_timer->start();
return err_str;
break;
default:
break;
}
}
Best,
Marek