c# - 从 UDP 连接 C# 获取客户端 ip

Question

我目前有一个服务器应用程序正在监听 UDP 数据包的端口。当一个发送到服务器时，它会正确接收并处理它。有什么方法可以获取数据包来源的 IP 地址吗？

下面是我创建套接字的方法

this.UDPListener = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);

IPEndPoint endPoint = new IPEndPoint(IPAddress.Any, Port);
this.UDPListener.Bind(endPoint);

SocketAsyncEventArgs socketEventArgs = new SocketAsyncEventArgs(); 
socketEventArgs.SetBuffer(this.ReceiveBuffer, 0, this.ReceiveBuffer.Length);
socketEventArgs.Completed += new EventHandler<SocketAsyncEventArgs>(OnReceive);
if (!this.UDPListener.ReceiveAsync(socketEventArgs))
    ThreadPool.QueueUserWorkItem(new WaitCallback((Object o) => this.OnReceive(this, socketEventArgs)));

当调用 OnReceive 时，没有任何内容包含消息来源的 ip。我查看了 SocketAsyncEventArgs，我看到的只是监听 ip。

编辑:

这是我最后做的。

this.UDPListener = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
this.UDPListener.Bind(new IPEndPoint(IPAddress.Any, Port));

EndPoint remoteEndPoint = new IPEndPoint(IPAddress.Any, 0);
this.UDPListener.BeginReceiveFrom(ReceiveBuffer, 0, ReceiveBuffer.Length, SocketFlags.None, ref remoteEndPoint, OnReceive, this.UDPListener);

然后在OnReceive中获取数据和信息

//Get the received message.
Socket receiveSocket = (Socket)AsyncResult.AsyncState;
EndPoint clientEndPoint = new IPEndPoint(IPAddress.Any, 0);
int udpMessageLength = receiveSocket.EndReceiveFrom(AsyncResult, ref clientEndPoint);
byte[] udpMessage = new byte[udpMessageLength];
Array.Copy(ReceiveBuffer, udpMessage, udpMessageLength);

//Start listening for a new message.
EndPoint remoteEndPoint = new IPEndPoint(IPAddress.Any, Int32.Parse(((IPEndPoint)receiveSocket.LocalEndPoint).Port.ToString()));
this.UDPListener.BeginReceiveFrom(ReceiveBuffer, 0, ReceiveBuffer.Length, SocketFlags.None, ref remoteEndPoint, OnReceive, this.UDPListener);

//Handle the received message
Debug.WriteLine("Recieved {0} bytes from {1}:{2} to {3}:{4}", udpMessageLength, ((IPEndPoint)clientEndPoint).Address, ((IPEndPoint)clientEndPoint).Port, ((IPEndPoint)receiveSocket.LocalEndPoint).Address, ((IPEndPoint)receiveSocket.LocalEndPoint).Port);

Answer 1

我不知道UdpClient，但是如果你直接使用Socket类，你可以调用.ReceiveFrom(byte[], ref EndPoint ) 方法，并通过第二个参数接收远程地址。