How does the C ＃ TCP server limit the number of connections to the same IP?

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One 、 explain

I have a question today , He's using RRQMSocket After creating the server , Want to achieve a function , Namely “ Limit the same IP Number of connections for ”. I told him , You can customize a plug-in , result .... He won't .

that ok, Let me give you an example .

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Two 、 Assembly source code

2.1 Source location

• Gitee
• Github

2.2 documentation

The front page of the document

3、 ... and 、 install

Nuget install RRQMSocket that will do , See link blog for specific steps .

VS、Unity Installation and use Nuget package

Four 、 Creating plug-ins

class LimitNumberOfConnectionsPlugin : TcpPluginBase
{
    
    [DependencyInject(2)]
    public LimitNumberOfConnectionsPlugin(int max,ILog logger)
    {
    
        this.Max = max;
        this.Logger = logger;

        logger.Message($" Restrict connection plug-ins to take effect , same IP Limit {
      max} A connection ");
    }

    readonly ConcurrentDictionary<string, Count> m_ipToCount = new ConcurrentDictionary<string, Count>();

    public int Max {
     get; }

    protected override void OnConnecting(ITcpClientBase client, ClientOperationEventArgs e)
    {
    
        Count count = m_ipToCount.GetOrAdd(client.IP, (s) => {
     return new Count(); });

        if (count.Increment() > this.Max)
        {
    
            count.Decrement();
            e.IsPermitOperation = false;// Indicates that connection is not allowed 
            e.Handled = true;// And the message has been processed .
            this.Logger.Warning($"IP={
      client.IP} The client of , The number of connections has reached the set threshold . Connection denied .");
            return;
        }
        base.OnConnecting(client, e);
    }

    protected override void OnDisconnected(ITcpClientBase client, ClientDisconnectedEventArgs e)
    {
    
        if (m_ipToCount.TryGetValue(client.IP,out Count count))
        {
    
            if (count.Decrement() == 0)
            {
    
                m_ipToCount.TryRemove(client.IP, out _);
            }
        }
        base.OnDisconnected(client, e);
    }
}

class Count
{
    
    private int num;

    public int Num
    {
    
        get {
     return num; }
    }

    public int Increment()
    {
    
        return Interlocked.Increment(ref num);
    }

    public int Decrement()
    {
    
        return Interlocked.Decrement(ref num);
    }
}

5、 ... and 、 Start the server

static void Main(string[] args)
{
    
    TcpService service = new TcpService();
    service.Connecting += (client, e) => {
     };// A client is connecting 
    service.Connected += (client, e) => {
     };// There is a client connection 
    service.Disconnected += (client, e) => {
     };// A client is disconnected 
    service.Received += (client, byteBlock, requestInfo) =>
    {
    
        // Receive message from client 
        string mes = Encoding.UTF8.GetString(byteBlock.Buffer, 0, byteBlock.Len);
        Console.WriteLine($" From {
      client.ID} Received information ：{
      mes}");

        client.Send(mes);// Return the received information directly to the sender 
    };

    service.Setup(new RRQMConfig()// Load configuration  
        .SetListenIPHosts(new IPHost[] {
     new IPHost("127.0.0.1:7789"), new IPHost(7790) })// Listen to two addresses at the same time 
        .SetMaxCount(10000)
        .SetThreadCount(100)
        .UsePlugin())
        .Start();// start-up 

    service.AddPlugin<LimitNumberOfConnectionsPlugin>();

    Console.ReadKey();
}

6、 ... and 、 effect

Because the code is all here , therefore , There is no need to upload the project .