多个客户端的C＃.NET UDP套接字异步

I have been looking around and I can't really find what I need, especially for UDP.

我一直在寻找,我无法真正找到我需要的东西,特别是对于UDP。

I'm trying to make a basic syslog server listening on port 514 (UDP).

我正在尝试使端口系统日志服务器侦听端口514(UDP)。

I have been following Microsoft's guide on MSDN: https://msdn.microsoft.com/en-us/library/system.net.sockets.udpclient.beginreceive(v=vs.110).aspx

我一直在关注MSDN上的微软指南:https://msdn.microsoft.com/en-us/library/system.net.sockets.udpclient.beginreceive(v=vs.110).aspx

It doesn't clearly state (or I'm blind) how to re-open the connection for more packets to be recieved.

它没有明确说明(或者我是盲目的)如何重新打开连接以获得更多的数据包。

Here is my code (basically the same from the link)

这是我的代码(链接基本相同)

     static void Main(string[] args)
    {
        try
        {
            ReceiveMessages();

            Console.ReadLine();

        }catch(SocketException ex)
        {
            if(ex.SocketErrorCode.ToString() == "AddressAlreadyInUse")
            {
                MessageBox.Show("Port already in use!");
            }
        }

    }

    public static void ReceiveMessages()
    {
        // Receive a message and write it to the console.



        UdpState s = new UdpState();

        Console.WriteLine("listening for messages");
        s.u.BeginReceive(new AsyncCallback(ReceiveCallback), s);
        RecieveMoreMessages(s);
    }

    public static void RecieveMoreMessages(UdpState s)
    {
        s.u.BeginReceive(new AsyncCallback(ReceiveCallback), s);
    }

    public static void ReceiveCallback(IAsyncResult ar)
    {
        UdpClient u = (UdpClient)((UdpState)(ar.AsyncState)).u;
        IPEndPoint e = (IPEndPoint)((UdpState)(ar.AsyncState)).e;

        Byte[] receiveBytes = u.EndReceive(ar, ref e);
        string receiveString = Encoding.ASCII.GetString(receiveBytes);

        Console.WriteLine("Received: {0}", receiveString);
    }

I have tried reiteration but I'm running into 'Running out of buffer space' error from the socket after 2 transactions.

我已经尝试过重复,但是在2次交易后我遇到了来自套接字的“用完缓冲区空间”错误。

Any ideas?

2 个解决方案

#1

If you insist on using the obsolete APM pattern you need to make ReceiveCallback issue the next BeginReceive call.

如果您坚持使用过时的APM模式,则需要使ReceiveCallback发出下一个BeginReceive调用。

Since UDP is connectionless async IO seems pointless. Probably, you should just use a synchronous receive loop:

由于UDP是无连接的异步IO似乎毫无意义。可能你应该使用同步接收循环:

while (true) {
 client.Receive(...);
 ProcessReceivedData();
}

Delete all that async code.

删除所有异步代码。

If you insist on async IO at least use ReceiveAsync.

如果你坚持异步IO至少使用ReceiveAsync。

#2

-1

The msdn code has a sleep which you eliminated. You don't need the sleep, but you do need a block. Try these changes

msdn代码有一个你消除的睡眠。你不需要睡觉,但你确实需要一个阻止。尝试这些更改

       public static void ReceiveMessages()
        {
            // Receive a message and write it to the console.



            UdpState s = new UdpState();

            Console.WriteLine("listening for messages");
            s.u.BeginReceive(new AsyncCallback(ReceiveCallback), s);
            //block
            while (true) ;
        }

        public static void RecieveMoreMessages(UdpState s)
        {
            s.u.BeginReceive(new AsyncCallback(ReceiveCallback), s);
        }

        public static void ReceiveCallback(IAsyncResult ar)
        {
            UdpClient u = (UdpClient)((UdpState)(ar.AsyncState)).u;
            IPEndPoint e = (IPEndPoint)((UdpState)(ar.AsyncState)).e;

            Byte[] receiveBytes = u.EndReceive(ar, ref e);
            string receiveString = Encoding.ASCII.GetString(receiveBytes);

            Console.WriteLine("Received: {0}", receiveString);
            RecieveMoreMessages(ar.AsyncState);
        }

#1