UDP打孔实现_C#/.NET问题-得得之家

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问题描述

我正在尝试完成 UDP 打孔.我的理论基于这篇文章和这篇 WIKI 页面，但我在 C# 编码方面遇到了一些问题.这是我的问题:

I am trying to accomplish UDP hole punching. I am basing my theory on this article and this WIKI page, but I am facing some issues with the C# coding of it. Here is my problem:

使用此处发布的代码我现在能够连接到远程计算机并在同一端口上侦听传入连接(将 2 个 UDP 客户端绑定到同一端口).

Using the code that was posted here I am now able to connect to a remote machine and listen on the same port for incoming connections (Bind 2 UDP clients to the same port).

由于某种原因，同一个端口的两个绑定会阻止对方接收任何数据.我有一个响应我的连接的 UDP 服务器，所以如果我在将任何其他客户端绑定到端口之前先连接到它，我会得到它的响应.

For some reason the two bindings to the same port block each other from receiving any data. I have a UDP server that responds to my connection so if I connect to it first before binding any other client to the port I get its responses back.

如果我将另一个客户端绑定到该端口，则任何一个客户端都不会收到任何数据.

If I bind another client to the port no data will be received on either clients.

以下是显示我的问题的 2 段代码.第一个连接到远程服务器以在 NAT 设备上创建规则，然后在不同的线程上启动侦听器以捕获传入的数据包.然后代码将数据包发送到本地 IP，以便侦听器获取它.第二个仅将数据包发送到本地 IP 以确保其正常工作.我知道这不是真正的打孔，因为我将数据包发送给自己，而根本没有使用 NAT 设备.我现在遇到了一个问题，如果我使用 NAT 设备之外的计算机进行连接，我认为这不会有什么不同.

Following are 2 code pieces that show my problem. The first connects to a remote server to create the rule on the NAT device and then a listener is started on a different thread to capture the incoming packets. The code then sends packets to the local IP so that the listener will get it. The second only sends packets to the local IP to make sure this works. I know this is not the actual hole punching as I am sending the packets to myself without living the NAT device at all. I am facing a problem at this point, and I don't imagine this will be any different if I use a computer out side the NAT device to connect.

2012 年 2 月 4 日我尝试使用网络上的另一台计算机和 WireShark(数据包嗅探器)来测试侦听器.我看到从另一台计算机传入的数据包，但侦听器 UDP 客户端(udpServer)或发送方 UDP 客户端(客户端)没有收到.

2/4/2012 I tried using another computer on my network and WireShark (packet sniffer) to test the listener. I see the packets incoming from the other computer but are not received by the listener UDP client (udpServer) or the sender UDP client (client).

2010 年 2 月 5 日我现在添加了一个函数调用，以在初始发送和接收数据包后关闭第一个 UDP 客户端，仅在第二个 UDP 客户端上监听端口.这有效，我可以从该端口上的网络内部接收数据包.我现在将尝试从网络外部发送和接收数据包.我一有发现就会发布我的发现.

2/5/2010 I have now added a function call to close the first UDP client after the initial sending and receiving of packets only living the second UDP client to listen on the port. This works and I can receive packets from inside the network on that port. I will now try to send and receive packets from outside the network. I will post my findings as soon as I find something.

使用此代码我在监听客户端上获取数据:

Using this code I get data on the listening client:

static void Main(string[] args)
{
    IPEndPoint localpt = new IPEndPoint(Dns.Resolve(Dns.GetHostName()).AddressList[0], 4545);

    ThreadPool.QueueUserWorkItem(delegate
    {
        UdpClient udpServer = new UdpClient();
        udpServer.ExclusiveAddressUse = false;
        udpServer.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
        udpServer.Client.Bind(localpt);

        IPEndPoint inEndPoint = new IPEndPoint(IPAddress.Any, 0);
        Console.WriteLine("Listening on " + localpt + ".");
        byte[] buffer = udpServer.Receive(ref inEndPoint); //this line will block forever
        Console.WriteLine("Receive from " + inEndPoint + " " + Encoding.ASCII.GetString(buffer) + ".");
    });

    Thread.Sleep(1000);

    UdpClient udpServer2 = new UdpClient(6000);

    // the following lines work and the data is received
    udpServer2.Connect(Dns.Resolve(Dns.GetHostName()).AddressList[0], 4545);
    udpServer2.Send(new byte[] { 0x41 }, 1);

    Console.Read();
}

如果我使用下面的代码，在我的客户端和服务器之间的连接和数据传输之后，正在监听的 UDP 客户端将不会收到任何东西:

If I use the following code, after the connection and data transfer between my client and server, the listening UDP client will not receive anything:

static void Main(string[] args)
{
    IPEndPoint localpt = new IPEndPoint(Dns.Resolve(Dns.GetHostName()).AddressList[0], 4545);

    //if the following lines up until serverConnect(); are removed all packets are received correctly
    client = new UdpClient();
    client.ExclusiveAddressUse = false;
    client.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
    client.Client.Bind(localpt);
    remoteServerConnect(); //connection to remote server is done here
                           //response is received correctly and printed to the console

    ThreadPool.QueueUserWorkItem(delegate
    {
        UdpClient udpServer = new UdpClient();
        udpServer.ExclusiveAddressUse = false;
        udpServer.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
        udpServer.Client.Bind(localpt);

        IPEndPoint inEndPoint = new IPEndPoint(IPAddress.Any, 0);
        Console.WriteLine("Listening on " + localpt + ".");
        byte[] buffer = udpServer.Receive(ref inEndPoint); //this line will block forever
        Console.WriteLine("Receive from " + inEndPoint + " " + Encoding.ASCII.GetString(buffer) + ".");
    });

    Thread.Sleep(1000);

    UdpClient udpServer2 = new UdpClient(6000);

    // I expected the following line to work and to receive this as well
    udpServer2.Connect(Dns.Resolve(Dns.GetHostName()).AddressList[0], 4545);
    udpServer2.Send(new byte[] { 0x41 }, 1);

    Console.Read();
}

UDP打孔实现

问题描述

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