通过所有数据包到达的 C# UDP 数据包丢失(WireShark)

Question

正如标题所说，我在 C# 中遇到 UDP 问题。 我正在尝试为游戏 DayZ 的 rcon 协议(protocol)构建一个库。

我的问题是我没有收到我应该收到的每个数据包。 发送命令后，服务器回复一个拆分答案。数据包 header 包含总数据包计数和当前数据包的索引。 现在，如果我应该得到 17 个数据包，我的应用程序中只会得到 8-15 个数据包。

在使用 WireShark 进行测试后，我现在知道所有包都已到达我的计算机。他们只是没有被我的应用程序或类似的东西识别。

我的实际问题是: 是否可以防止丢失我的网卡和我的应用程序之间的包？或者 为什么会这样？

这是我当前的代码。它很脏，因为我在没有按预期工作后将它拆开:

    private Socket _udpClient;
    private Thread _receiverThread;
    private Thread _workerThread;
    private Queue<byte[]> _packetQueue;
    private PacketBuffer[] MessageBuffer;
    private byte SenderSequence = 0;
    private IPEndPoint connection;

    public RCon(IPAddress ip, int port)
    {
        connection = new IPEndPoint(ip, port);
        _udpClient = new Socket(connection.Address.AddressFamily, SocketType.Dgram, ProtocolType.Udp);
        _udpClient.Connect(connection);
        MessageBuffer = new PacketBuffer[256];
        _packetQueue = new Queue<byte[]>();

        _receiverThread = new Thread(new ThreadStart(ReceiveCallback));
        _receiverThread.IsBackground = true;
        _receiverThread.Priority = ThreadPriority.AboveNormal;
        _receiverThread.Start();
        _workerThread = new Thread(new ThreadStart(WorkerCallback));
        _workerThread.IsBackground = true;
        _workerThread.Start();
    }

    public void Login(string password)
    {
        LoginPacket packet = new LoginPacket(password);

        _udpClient.Send(packet.Bytes);
    }

    public void SendCommand(string command)
    {
        CommandPacket packet = new CommandPacket(SenderSequence, command);
        SenderSequence++;

        _udpClient.Send(packet.Bytes);
    }

    private void ReceiveCallback()
    {

        while (true)
        {
                byte[] buffer = new byte[1036];
                if (_udpClient.Receive(buffer) > 0)
                    _packetQueue.Enqueue(buffer);
        }
    }

    private void WorkerCallback()
    {
        while (true)
        {
            if (_packetQueue.Count > 0)
            {
                byte[] buffer = _packetQueue.Dequeue();

                if (buffer != null)
                {
                    try
                    {
                        Packet receivedPacket = Packet.ParseIncoming(buffer);

                        OnPacketReceived(new PacketReceivedEventArgs(receivedPacket));

                        switch (receivedPacket.Type)
                        {
                            case PacketType.Message:
                                OnMessageReceived(new MessageReceivedEventArgs(receivedPacket.Content));
                                MessageCallbackPacket packet = new MessageCallbackPacket(receivedPacket.SequenceNumber);
                                _udpClient.Send(packet.Bytes);
                                break;
                            case PacketType.CommandCallback:
                                if (MessageBuffer[receivedPacket.SequenceNumber] == null)
                                    MessageBuffer[receivedPacket.SequenceNumber] = new PacketBuffer(receivedPacket);
                                else
                                    MessageBuffer[receivedPacket.SequenceNumber].AddPacket(receivedPacket);

                                if (MessageBuffer[receivedPacket.SequenceNumber].IsComplete)
                                    OnCommandCallback(new CommandCallbackEventArgs(MessageBuffer[receivedPacket.SequenceNumber].GetContent()));
                                break;
                        }
                    }
                    catch (ArgumentException) { }
                    catch (OverflowException) { }
                    catch (FormatException) { }
                }
            }
        }
    }

Answer 1

这通常是因为您没有足够快地使用数据报，因此内核套接字缓冲区已满并且网络堆栈开始丢弃新到达的数据包。几点:

• 增加套接字上的接收缓冲区，
• 不要在每次迭代时都获取锁 - 尽可能多地读取，然后将数据放入队列，
• 考虑使用非阻塞方法而不是线程。