Issue with UDP connection

[spiderman07]

When creating a new connection in DLT Viewer, UTP type one with Multicast on network device enabled and ip provided and correct network interface selected, i get error on DLT Viewer saying Binding failed with this error(pulled from the code): QAbstractSocket::SocketAddressNotAvailableError

The device is connected to that network and is responding to ping. Also i can see wireshark packets comming from daemon from target.

In order to fix it i changed on the code in src/mainwindow.cpp line 3112:

bindstate = ecuitem->socket->bind(QHostAddress(ecuitem->getmcastIP()), ecuitem->getIpport(),QUdpSocket::ShareAddress );

To this:

bindstate = ecuitem->socket->bind(ecuitem->getIpport(),QUdpSocket::ShareAddress );

Basically i removed the ip adress used for binding and let it bind on the port. Then it nicely joins the multicast group and logs do appear.

Is this a bug in code? Anyone tested this UDP connection until now?

PS: let me know if you need any more info.

Regards, Razvan

[alexmucde]

Is this issue in Windows or Linux? Do you have several Ethernet interfaces on your system? Did you seleected the right Multicast Interface? Please check your configuration

Alex

[spiderman07]

Hi.

Is this issue in Windows or Linux? -> Windows Do you have several Ethernet interfaces on your system? -> Yes i have more. 2 adapters +1 from virtual box Did you seleected the right Multicast Interface? yes i did select the correct one. i have tried all of them.

[olaf-dreyer]

There is a bug in the Qt code (as far as I know). In my own product, I needed to implement a workaround:

    if(!m_strLocalAddress.compare("0.0.0.0") || m_strLocalAddress.isEmpty())
        bBound = m_pUdpRxSocket->bind(QHostAddress::Any, m_iLocalPort, QUdpSocket::ShareAddress);
    else
        bBound = m_pUdpRxSocket->bind(QHostAddress(m_strLocalAddress), m_iLocalPort, QUdpSocket::ShareAddress);

    quint32 group = QHostAddress(m_strRemoteAddress).toIPv4Address();

    if(bBound && (group >= 0xE0000000) && (group <0xF0000000))
    {

// qDebug() << "ComDeviceSocket::open: searching interface for multicasting";

        int i = -1;

        QList<QNetworkInterface> lIF = QNetworkInterface::allInterfaces();
        for(i = 0; i < lIF.size(); i++)
        {

// qDebug() << "ComDeviceSocket::open: interface" << i << ":" << lIF.at(i).humanReadableName();

            int a = -1;

            QList<QNetworkAddressEntry> lAddr = lIF.at(i).addressEntries();
            for(a = 0; a < lAddr.size(); a++)
            {
                QNetworkAddressEntry e = lAddr.at(a);
                QHostAddress addr = e.ip();

// qDebug() << "ComDeviceSocket::open: interface" << i << ", addr" << a << ":" << addr.toString();

                if(addr == QHostAddress(m_strLocalAddress) || !m_strLocalAddress.compare("0.0.0.0") || m_strLocalAddress.isEmpty())
                {
                    qDebug() << "ComDeviceSocket::open: join group on interface" << i << ", addr" << a << ":" << addr.toString();

                    m_pUdpRxSocket->joinMulticastGroup(QHostAddress(m_strRemoteAddress), lIF.at(i));
                    //m_pUdpTxSocket->joinMulticastGroup(QHostAddress(m_strRemoteAddress), lIF.at(i));
                }
            }
        }
    }

    if(!bBound)
        qDebug() << "ComDeviceSocket::open: Bind problem, unable to bind to" << m_strLocalAddress;
    else
        qDebug() << "ComDeviceSocket::open: bound to" << m_pUdpRxSocket->localAddress() << ":" << m_pUdpRxSocket->localPort();

[alexmucde]

Can anyone provide a patch/Pull Request for this issue? Or is it solved in Qt with any release of Qt?

[sebastianlipponer]

I am able to connect via UDP with Multicast on network interface enabled using 457cef969 based on QT 5.14.1.

[alexmucde]

Looks like it is solved, please reopen if needed.