正确使用 UDP 数据报套接字

本文关键字：数据报 套接字 UDP | 更新日期: 2023-09-27 18:31:59

我的基类中有以下代码（下面提供的截图）用于处理UDP套接字。我正在添加对WinRT的支持（由WINRT的 #define 控制）。我有一切适用于 .Net，但我的 WinRT 实现出了点问题。当我发送数据时，服务器端没有收到它。知道出了什么问题吗？我在客户端没有看到任何错误，只是服务器上没有显示任何内容。我已经成功地让我的TCP套接字类工作，以类似的方式使用DataWriter。

        public UdpSocketClient(IPEndPoint remoteEndPoint, int localPort)
        {
            this.remoteEndPoint = remoteEndPoint;
#if WINRT
            this.socket = new DatagramSocket();
            this.socket.MessageReceived += ReceiveCallback;
            // Bind to any port
            Logger.Debug("{0}: UdpSocketClient created. Binding to port {1}.", this, (localPort == 0) ? "[any]" : localPort.ToString());
            IAsyncAction bindAction = this.socket.BindEndpointAsync(new HostName("localhost"), localPort == 0 ? "0" : localPort.ToString());
            bindAction.AsTask().Wait();
            Logger.Trace("{0}: Bind Complete to port {1}", this, this.socket.Information.LocalServiceName);
            // Get IOutputStream
            Logger.Trace("{0}: Getting output stream to {1}.", this, remoteEndPoint);
            IAsyncOperation<IOutputStream> asyncOutput = this.socket.GetOutputStreamAsync(remoteEndPoint.address, remoteEndPoint.port.ToString());
            asyncOutput.AsTask().Wait();
            Logger.Trace("{0}: Got output stream.", this);
            // Create DataWriter
            dataWriter = new DataWriter(asyncOutput.GetResults());
#else
            ...
#endif
        }

        public void SendBuffer(ByteBuffer buffer, int wait = 0)
        {
#if WINRT
            Logger.Trace("{0}: Sending buffer. Wait = {1}", this, wait);
            for (int i = 0; i < buffer.WriteSize(); i++)
                dataWriter.WriteByte(buffer.Buffer()[i]);
            DataWriterStoreOperation op = dataWriter.StoreAsync();
            if (wait != 0) op.AsTask().Wait(wait);
            else op.AsTask().Wait();
            Logger.Trace("{0}: Sending complete.", this);
#else
        ...
#endif
        }

一些相关日志：

04/23 19:08:57.504 DEBUG: Area Sync: UdpSocketClient created. Binding to port [any].
04/23 19:08:57.505 TRACE: Area Sync: Bind Complete to port 59518
04/23 19:08:57.506 TRACE: Area Sync: Getting output stream to 71.227.179.128:1302.
04/23 19:08:57.507 TRACE: Area Sync: Got output stream.
04/23 19:08:57.604 TRACE: Area Sync: Sending contact packet.
04/23 19:08:57.604 TRACE: Area Sync: Sending buffer. Wait = 0
04/23 19:08:57.605 TRACE: Area Sync: Sending complete.

正确使用 UDP 数据报套接字

我想通了。显然它不喜欢我的绑定代码。文档说您应该能够将 null 传递到绑定中，但我总是有一个例外。因此，如果我使用ConnectAsync API，它可以工作：

        public UdpSocketClient(IPEndPoint remoteEndPoint, int localPort)
        {
            this.remoteEndPoint = remoteEndPoint;
#if WINRT
            this.socket = new DatagramSocket();
            this.socket.MessageReceived += ReceiveCallback;
            Logger.Trace("{0}: Connecting to {1}.", this, remoteEndPoint);
            IAsyncAction connectAction = this.socket.ConnectAsync(remoteEndPoint.address, remoteEndPoint.port.ToString());
            connectAction.AsTask().Wait();
            Logger.Trace("{0}: Connect Complete. Status {1}, ErrorCode {2}", this, connectAction.Status, 
                connectAction.ErrorCode != null ? connectAction.ErrorCode.Message : "None");
            dataWriter = new DataWriter(this.socket.OutputStream);
#else
            ...
#endif
        }
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