使用UDP接收和處理連續數據包

Question

這是我當前的設置（使用UDP）：

void OnDataReceived(IAsyncResult result)
{

    IPEndPoint ep = new IPEndPoint(IPAddress.Any, 0);

    byte[] buffer = socket.EndReceive(result, ref ep);

    Packet p = new Packet(Encoding.ASCII.GetString(buffer, 0, buffer.Length));

    //process packet

    socket.BeginReceive(new AsyncCallback(OnDataReceived), socket);

}

我想知道如果我在調用EndReceive后立即調用socket.BeginReceive會發生什么情況，然后處理數據包以獲得這樣的連續數據包流：

void OnDataReceived(IAsyncResult result)
{

    IPEndPoint ep = new IPEndPoint(IPAddress.Any, 0);

    byte[] buffer = socket.EndReceive(result, ref ep);
    socket.BeginReceive(new AsyncCallback(OnDataReceived), socket);

    Packet p = new Packet(Encoding.ASCII.GetString(buffer, 0, buffer.Length));

    //process packets

}

如果我在調用BeginReceive時收到數據包，是否會以某種方式與當前數據包處理沖突？

此外，如果這不會發生沖突會改變為TCP使這個功能失效嗎？

Answer 1

看起來你正在那里創建某種遞歸處理程序。 我不確定這是如何工作的，可能不是很好。 我通常會選擇一個單獨的讀取器線程來偵聽傳入的數據並將其傳遞給事件。 這對我來說過去很好。 我沒有考慮過使用async。

下面是一些關於如何使用單獨的線程來處理傳入的UDP數據的示例代碼。 它不完整，但應該讓你知道如何設置它。

    private Thread _udpReadThread;
    private volatile bool _terminateThread;

    public event DataEventHandler OnDataReceived;
    public delegate void DataEventHandler(object sender, DataEventArgs e);

    private void CreateUdpReadThread()
    {
        _udpReadThread = new Thread(UdpReadThread) { Name = "UDP Read thread" };
        _udpReadThread.Start(new IPEndPoint(IPAddress.Any, 1234));
    }

    private void UdpReadThread(object endPoint)
    {
        var myEndPoint = (EndPoint)endPoint;
        var udpListener = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
        udpListener.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);

        // Important to specify a timeout value, otherwise the socket ReceiveFrom() 
        // will block indefinitely if no packets are received and the thread will never terminate
        udpListener.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReceiveTimeout, 100);
        udpListener.Bind(myEndPoint);

        try
        {
            while (!_terminateThread)
            {
                try
                {
                    var buffer = new byte[1024];
                    var size = udpListener.ReceiveFrom(buffer, ref myEndPoint);
                    Array.Resize(ref buffer, size);

                    // Let any consumer(s) handle the data via an event
                    FireOnDataReceived(((IPEndPoint)(myEndPoint)).Address, buffer);
                }
                catch (SocketException socketException)
                {
                    // Handle socket errors
                }
            }
        }
        finally
        {
            // Close Socket
            udpListener.Shutdown(SocketShutdown.Both);
            udpListener.Close();
        }
    }

    public class DataEventArgs : EventArgs
    {
        public byte[] Data { get; private set; }
        public IPAddress IpAddress { get; private set; }

        public DataEventArgs(IPAddress ipaddress, byte[] data)
        {
            IpAddress = ipaddress;
            Data = data;
        }
    }