How to block a client in C sharp socket programming (very very URGENT)

EDN Admin · Jun 18, 2009

I have one server and client application using socket programming in c#. In this, max. 10 clients can be connected to the server at a time. But my requirement is that I have to block one of the clients via IP address when I am sending messages through server.. Please help with blocking. The program is given below. Please help me. I am a fresher in C# using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Text; using System.Windows.Forms; using System.Net.Sockets; using System.Net; namespace Server { public partial class SocketServer : Form { const int MAX_CLIENTS = 10; public AsyncCallback pfnWorkerCallBack; private Socket m_mainSocket; private Socket[] m_workerSocket = new Socket[10]; private int m_clientCount = 0; private byte[] byData; public SocketServer() { InitializeComponent(); textBoxIP.Text = GetIP(); } String GetIP() { String strHostName = Dns.GetHostName(); // Find host by name IPHostEntry iphostentry = Dns.GetHostByName(strHostName); // Grab the first IP addresses String IPStr = ""; foreach (IPAddress ipaddress in iphostentry.AddressList) { IPStr = ipaddress.ToString(); ip = IPStr; return IPStr; } ip = IPStr; return IPStr; } private void Form1_Load(object sender, EventArgs e) { } private void buttonStartListen_Click(object sender, EventArgs e) { try { // Check the port value if (textBoxPort.Text == "") { MessageBox.Show("Please enter a Port Number"); return; } string portStr = textBoxPort.Text; int port = System.Convert.ToInt32(portStr); // Create the listening socket... m_mainSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); IPEndPoint ipLocal = new IPEndPoint(IPAddress.Any, port); // Bind to local IP Address... m_mainSocket.Bind(ipLocal); // Start listening... m_mainSocket.Listen(4); // Create the call back for any client connections... m_mainSocket.BeginAccept(new AsyncCallback(OnClientConnect), null); UpdateControls(true); } catch (SocketException se) { MessageBox.Show(se.Message); } } private void UpdateControls(bool listening) { buttonStartListen.Enabled = !listening; buttonStopListen.Enabled = listening; } public delegate void UpdateTextCallback(string message, object obj); public void OnClientConnect(IAsyncResult asyn) { try { // Here we complete/end the BeginAccept() asynchronous call // by calling EndAccept() - which returns the reference to // a new Socket object m_workerSocket[m_clientCount] = m_mainSocket.EndAccept(asyn); // Let the worker Socket do the further processing for the // just connected client WaitForData(m_workerSocket[m_clientCount]); // Now increment the client count ++m_clientCount; // Display this client connection as a status message on the GUI String str = String.Format("Client # {0} connected", m_clientCount); //textBoxMsg.Text = str; textBoxMsg.BeginInvoke(new UpdateTextCallback(UpdateText), new object[] { str, textBoxMsg }); // Since the main Socket is now free, it can go back and wait for // other clients who are attempting to connect m_mainSocket.BeginAccept(new AsyncCallback(OnClientConnect), null); } catch (ObjectDisposedException) { System.Diagnostics.Debugger.Log(0, "1", "n OnClientConnection: Socket has been closedn"); } catch (SocketException se) { MessageBox.Show(se.Message); } } private void UpdateText(string message, object ctrl) { if (ctrl is TextBox) textBoxMsg.Text = message; if(ctrl is RichTextBox) richTextBoxReceivedMsg.AppendText(message); } public class SocketPacket { public System.Net.Sockets.Socket m_currentSocket; public byte[] dataBuffer = new byte[1]; } public void WaitForData(System.Net.Sockets.Socket soc) { try { if (pfnWorkerCallBack == null) { // Specify the call back function which is to be // invoked when there is any write activity by the // connected client pfnWorkerCallBack = new AsyncCallback(OnDataReceived); } SocketPacket theSocPkt = new SocketPacket(); theSocPkt.m_currentSocket = soc; // Start receiving any data written by the connected client // asynchronously soc.BeginReceive(theSocPkt.dataBuffer, 0, theSocPkt.dataBuffer.Length, SocketFlags.None, pfnWorkerCallBack, theSocPkt); } catch (SocketException se) { MessageBox.Show(se.Message); } } public void OnDataReceived(IAsyncResult asyn) { try { SocketPacket socketData = (SocketPacket)asyn.AsyncState; int iRx = 0; // Complete the BeginReceive() asynchronous call by EndReceive() method // which will return the number of characters written to the stream // by the client iRx = socketData.m_currentSocket.EndReceive(asyn); char[] chars = new char[iRx + 1]; System.Text.Decoder d = System.Text.Encoding.UTF8.GetDecoder(); int charLen = d.GetChars(socketData.dataBuffer, 0, iRx, chars, 0); System.String szData = new System.String(chars); //richTextBoxReceivedMsg.AppendText(szData); richTextBoxReceivedMsg.BeginInvoke(new UpdateTextCallback(UpdateText), new object[] { szData, richTextBoxReceivedMsg }); // Continue the waiting for data on the Socket WaitForData(socketData.m_currentSocket); } catch (ObjectDisposedException) { System.Diagnostics.Debugger.Log(0, "1", "nOnDataReceived: Socket has been closedn"); } catch (SocketException se) { MessageBox.Show(se.Message); } } private void buttonStopListen_Click(object sender, EventArgs e) { CloseSockets(); UpdateControls(false); } void CloseSockets() { if (m_mainSocket != null) { m_mainSocket.Close(); } for (int i = 0; i < m_clientCount; i++) { if (m_workerSocket != null) { m_workerSocket.Close(); m_workerSocket = null; } } } private void buttonSendMsg_Click(object sender, EventArgs e) { try { Object objData = richTextBoxSendMsg.Text; byData = System.Text.Encoding.ASCII.GetBytes(objData.ToString()); for (int i = 0; i < m_clientCount; i++) { if (m_workerSocket != null) { if (m_workerSocket.Connected) { m_workerSocket.Send(byData); } } } } catch (SocketException se) { MessageBox.Show(se.Message); } } private void Form1_Minimize(object sender, System.EventArgs e) { if (FormWindowState.Minimized == WindowState) { Hide(); this.notify.Visible = true; } } private void Form1_Resize(object sender, System.EventArgs e) { Show(); WindowState = FormWindowState.Normal; this.notify.Visible = false; }

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How to block a client in C sharp socket programming (very very URGENT)

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