为TcpListener和TcpClient绑定相同的端点

Question

I have a listener that listens to the localhost on an assigned portnumber like this:

TcpListener listener = new TcpListener(localIP);
listener.Start();

while (true) {
listen:
    if (!listener.Pending()) {
        Thread.Sleep(100);
        goto listen;
    }
    Socket socket = listener.AcceptSocket();
}

Now the same program should make a connection to other instances of this program like this:

TcpClient client = new TcpClient(localIP); //localendpoint should use same port
client.Connect("localhost", remotePort);

As you can see I'm binding the same IPEndPoint localIP for both the listener and client . So that whenever another instance of the program has a connection with this one, the socket in the listener could give me it's RemoteEndPoint . So that I don't get a random port number generated by the system. Of course this won't work and I get this error:

Only one usage of each socket address (protocol/network address/port) is normally permitted

Since both listener and client are binded to the same IPEndPoint localIP .

Is there a workaround so that I can bind a listener and client to the same EndPoint? Because I want to get the portnumber from socket.RemoteEndPoint in the listener. This portnumber should be the portnumber that is assigned to each individual instance of the program.

Answer 1

好吧，根据问题的评论，最好的解决方案是仅通过套接字连接发送程序正在侦听的端口号。

Answer 2

I recommend switching to WCF for your communications. It gives you a lot of handy tools for abstracting over serialization, the transport protocol, security, configuration, etc. Eventually, WCF lets you build service-oriented apps for a diverse client ecosystem easier than doing all the hard work yourself.

One of the features WCF has to offer is a so-called Duplex Binding , which should give you what you want: a connecting client immediately announces a way to be called back.

If you still need to communicate your network topology, than you can still do so using WCF; And for that I recommend implementing a separate service interface that takes care of network topology exclusively.

A tutorial + example on getting started with WCF, and creating clean code can be found here and here .