How can I wrap the ReceivePackets into Thread/Task/Backgroundworker? I tried to use all these, but I got error: "System.AccessViolationException system.accessviolationexception attempted to read or write protected memory"

Thats my try. thread creation:

PacketDevice selectedDevice = allDevices[deviceIndex - 1];

// Open the device
using (communicator =
    selectedDevice.Open(65536,                                  // portion of the packet to capture
                                                                // 65536 guarantees that the whole packet will be captured on all the link layers
                        PacketDeviceOpenAttributes.Promiscuous, // promiscuous mode
                        1000))                                  // read timeout
{
    Console.WriteLine("Listening on "   selectedDevice.Description   "...");

    // start the capture
    pThread.Start();

}

recvP function and packet handler:

private void recvP()
{
    communicator.ReceivePackets(0, PacketHandler);
}

// Callback function invoked by Pcap.Net for every incoming packet
private void PacketHandler(Packet packet)
{
    UdpDatagram datagram = packet.Ethernet.IpV4.Udp;
    if (datagram != null && datagram.SourcePort == 6969)
    {
        MemoryStream stream = datagram.Payload.ToMemoryStream();
        byte[] byteStream = stream.ToArray();

        current_packet_id = BitConverter.ToUInt16(byteStream, 0);
        Console.WriteLine("Got chunk number: "   current_packet_id);
        if (current_packet_id < last_packet_id) // new image (first chunk of the image)
        {
            if (!firstImage)
                ShowImage(); // show image if all his chunks arrived

            data.Clear(); // clear all data from past images
            data.AddRange(byteStream.Skip(2).Take(byteStream.Length - 2).ToList());
        }
        else // next packets (same chunk continues)
            data.AddRange(byteStream.Skip(2).Take(byteStream.Length - 2).ToList());

        last_packet_id = current_packet_id;
    }
}

CodePudding user response：

I got it, the fix was to move the using construction into the thread function, and leave only the pThread.Start()

private void recvP()
{
    // open the device
    using (communicator =
    selectedDevice.Open(65536,                         // portion of the packet to capture
                                                        // 65536 guarantees that the whole packet will be captured on all the link layers
            PacketDeviceOpenAttributes.Promiscuous,  // promiscuous mode
            1000))                                  // read timeout
    {
        Console.WriteLine("Listening on "   selectedDevice.Description   "...");
        communicator.ReceivePackets(0, PacketHandler);
    }
}