Develop Reference

TCP chat client/server won't work off localhost

I am currently learning to program a chat room application that uses a server. So far everything works fine if I run the server and multiple instances of the application on a single machine. When I try to run the server on one machine and the actual chat application from another, I get an exception that reads "a connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond (Ipaddress)(port)"
Server side code:
using System;
using System.Net;
using System.Net.Sockets;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Collections;
using System.Text;
using System.Threading;
namespace ChatAppServer
{
class Program
{
public static Hashtable ClientList = new Hashtable();
const int PORT = 321;
string localIp;
static void Main(string[] args)
{
TcpListener sckServer = new TcpListener(PORT);
TcpClient sckClient = default(TcpClient);
int counter = 0;
sckServer.Start();
Console.WriteLine("Chat Server is now Running ....");
counter = 0;
//Parser myParser = new Parser();
while (true)
{
counter = counter + 1;
sckClient = sckServer.AcceptTcpClient();
string clientData = "";
byte[] recieveData = new byte[10025];
NetworkStream netStream = sckClient.GetStream();
netStream.Read(recieveData, 0, (int)sckClient.ReceiveBufferSize);
clientData = System.Text.Encoding.ASCII.GetString(recieveData);
clientData = clientData.Substring(0, clientData.IndexOf("$"));
ClientList.Add(clientData, sckClient);
Broadcast(clientData + " joined the chat", clientData, false);
Console.WriteLine(clientData + " connected to the chat");
handleClient client = new handleClient();
client.ClientStart(sckClient, clientData, ClientList);
}
sckClient.Close();
sckServer.Stop();
Console.WriteLine("exit");
Console.ReadLine();
}
public static void Broadcast(string msg, string userName, bool flag)
{
foreach (DictionaryEntry Item in ClientList)
{
TcpClient sckBroadcast;
sckBroadcast = (TcpClient)Item.Value;
NetworkStream broadcastStream = sckBroadcast.GetStream();
Byte[] broadcastData = null;
if (flag == true)
{
broadcastData = Encoding.ASCII.GetBytes(userName + ": " + msg);
}
else
{
broadcastData = Encoding.ASCII.GetBytes(msg);
}
broadcastStream.Write(broadcastData, 0, broadcastData.Length);
broadcastStream.Flush();
}
}
public class handleClient
{
TcpClient sckClient;
string clId;
Hashtable ClientList;
public void ClientStart(TcpClient inSckClient, string clientId, Hashtable clist) {
this.sckClient = inSckClient;
this.clId = clientId;
this.ClientList = clist;
Thread ctThread = new Thread(runChat);
ctThread.Start();
}
private void runChat() {
int requestCount = 0;
byte[] recieveData = new byte[10025];
string clientData = "";
string rCount = null;
while ((true))
{
try
{
requestCount += 1;
NetworkStream netStream = sckClient.GetStream();
netStream.Read(recieveData, 0, (int)sckClient.ReceiveBufferSize);
clientData = System.Text.Encoding.ASCII.GetString(recieveData);
clientData = clientData.Substring(0, clientData.IndexOf("$"));
Console.WriteLine(clId + " : " + clientData);
rCount = Convert.ToString(requestCount);
Program.Broadcast(clientData, clId, true);
}
catch(Exception ex)
{
Console.WriteLine(ex.ToString());
}
}
}
}
}
}
Chat room application code:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
//Need for the application
using System.Net;
using System.Net.Sockets;
using System.Threading;
namespace ChatApp
{
public partial class Form1 : Form
{
System.Net.Sockets.TcpClient sckClient = new System.Net.Sockets.TcpClient();
NetworkStream svrStream = default(NetworkStream);
string recieveData = null;
public Form1()
{
InitializeComponent();
btnSend.Enabled = false;
}
private void btnConnect_Click(object sender, EventArgs e)
{
recieveData = "Connected to Server";
msg();
int serverPort = Convert.ToInt32(txtServerPort.Text);
sckClient.Connect(txtServerIp.Text, serverPort);
svrStream = sckClient.GetStream();
byte[] outStream = System.Text.Encoding.ASCII.GetBytes(txtUserName.Text + "$");
svrStream.Write(outStream, 0, outStream.Length);
svrStream.Flush();
Thread ctThread = new Thread(MessageCallBack);
btnSend.Enabled = true;
btnConnect.Enabled = false;
txtUserName.Enabled = false;
txtServerIp.Enabled = false;
txtServerPort.Enabled = false;
ctThread.Start();
}
private void MessageCallBack()
{
while(true)
{
svrStream = sckClient.GetStream();
int buffSize = 0;
byte[] inStream = new byte[10025];
buffSize = sckClient.ReceiveBufferSize;
svrStream.Read(inStream, 0, buffSize);
string returnData = System.Text.Encoding.ASCII.GetString(inStream);
recieveData = "" + returnData;
msg();
}
}
//function to display data strings
private void msg()
{
if (this.InvokeRequired)
{
this.Invoke(new MethodInvoker(msg));
}
else
{
lstMessage.Items.Add(recieveData);
}
}
private void btnSend_Click(object sender, EventArgs e)
{
byte[] outStream = System.Text.Encoding.ASCII.GetBytes(txtMessage.Text + "$");
svrStream.Write(outStream, 0, outStream.Length);
svrStream.Flush();
txtMessage.Text = "";
}

I have two troubles with your code :
Do not use .ReceiveBufferSize value because it's a different value of your byte array length. And you can have an index out of range exception.
You have a problem of concurrency in the server side. More than 1 thread try to access to the ClientList and this collection is not thread-safe.
To resolve this, you can use the lock keyword
private static object _lock = new object();
//...
lock (_lock)
{
ClientList.Add(clientData, sckClient);
}
lock (_lock)
{
Broadcast(clientData + " joined the chat", clientData, false);
}
//...
lock (_lock)
{
Program.Broadcast(clientData, clId, true);
}
As you're a beginner, i would give you some tips.
Try to use the asynchronous network functions (better than raw threads), an example there.
There is a lot of tutorials about safety with severals connections in C# (with some thing else, better, than the lock keyword).

Ident server not returning Identification on port 113

I am trying to program an ident sever to deal with the identity protocol requests from an irc server that I am programming an irc client for. The problem is I try to print to the screen the what I receive but nothing prints. I am not getting an error code.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net;
using System.Net.Sockets;
namespace ConnectIRC
{
class IdentityClass
{
private const int bufSize = 32;
public void IdentityRequest() {
TcpListener listener = null;
int port = 113;
IPEndPoint hostInfo = new IPEndPoint(IPAddress.Any, 113);
listener = new TcpListener(hostInfo);
listener.Start();
byte[] rcvBuffer = new byte[bufSize];
int rec;
for (; ; )
{
TcpClient client = null;
NetworkStream netStream = null;
client = listener.AcceptTcpClient();
if (listener.Pending())
{
Console.WriteLine("Connection was made");
}
netStream = client.GetStream();
//byte[] rcvBuffer = new byte[bufSize];
rec = netStream.Read(rcvBuffer, 0, rcvBuffer.Length);
Array.Resize(ref rcvBuffer, rec);
Console.WriteLine(Encoding.ASCII.GetString(rcvBuffer));
netStream.Close();
client.Close();
}
}
}
}

This is a very basic implementation of an ident server
Obviously it only accepts one connection and closes
Note you'll need to have a port mapped through your router for this to work
public class Ident
{
private readonly TcpListener _listener;
private readonly string _userId;
public Ident(string userId)
{
_userId = userId;
_listener = new TcpListener(IPAddress.Any, 113);
}
public void Start()
{
Console.WriteLine("Ident started");
_listener.Start();
var client = _listener.AcceptTcpClient();
_listener.Stop();
Console.WriteLine("Ident got a connection");
using (var s = client.GetStream())
{
var reader = new StreamReader(s);
var str = reader.ReadLine();
var writer = new StreamWriter(s);
Console.WriteLine("Ident got: " + str + ", sending reply");
writer.WriteLine(str + " : USERID : UNIX : " + _userId);
writer.Flush();
Console.WriteLine("Ident sent reply");
}
Console.WriteLine("Ident server exiting");
}
}

Get all bytes from stream

I'm writing a proxy in c# and I wrote this method to get bytes from the stream but after looking at answer in this thread : Proxy won't work in chrome and only partly in firefox I realize that I do not get all the bytes. How can I solve this?
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using System.Windows.Forms;
namespace LexProxy
{
class ProxyServer
{
private TcpListener tcpListener;
public ProxyServer()
{
this.tcpListener = new TcpListener(IPAddress.Any, 3000);
this.tcpListener.Start();
while (true)
{
Console.Write("Waiting for a connection... ");
TcpClient client = tcpListener.AcceptTcpClient();
Thread thread = new Thread(delegate()
{
Serve(client);
});
thread.Start();
}
}
private void Serve(TcpClient client)
{
Console.WriteLine("Connected!");
NetworkStream stream = client.GetStream();
byte[] request = GetBytesFromStream(stream, client.ReceiveBufferSize);
if (request != null)
{
string requestString = System.Text.Encoding.UTF8.GetString(request);
string[] requestParts = requestString.Split(' ');
if (requestParts.Length >= 2)
{
string method = requestParts[0];
if (!requestParts[1].Contains("http://") && !requestParts[1].Contains("https://"))
requestParts[1] = "http://" + requestParts[1];
Uri uri = new Uri(requestParts[1], UriKind.RelativeOrAbsolute);
string host = StringUtils.ReplaceFirst(uri.Host, "www.", "");
int port = uri.Port;
byte[] response = getResponse(host, port, request);
if (response != null)
stream.Write(response, 0, response.Length);
client.Close();
}
}
}
private byte[] getResponse(string host, int port, byte[] request)
{
TcpClient client = new TcpClient(host, port);
NetworkStream stream = client.GetStream();
stream.Write(request, 0, request.Length);
byte[] response = GetBytesFromStream(stream, client.ReceiveBufferSize);
return response;
}
private byte[] GetBytesFromStream(NetworkStream stream, int bufferSize)
{
Byte[] bytes = new Byte[bufferSize];
int i;
while ((i = stream.Read(bytes, 0, bytes.Length)) != 0)
{
return bytes;
}
return null;
}
}
}

Try out this sample Proxy Server instead:
http://times.imkrisna.com/2011/08/simple-http-proxy-server-c-source-code/

You're doing this wrong. Instead of trying to gather the entire response before sending it downstream, you should just be copying bytes as they arrive. No need to add latency.
But note that the code you have written in getAllBytesFromStream() is nonsense. You have a while loop with an unconditional return statement in it. How is that ever going to execute more than once?

Infrared command with pocket pc

i have an infrared remote control and i want replace this with my PPC.
My Mitac P550 has an infrared serial port but i dont know how to retrieve and resend the sequence of byte.....
It's possible get the data with SerialPort component of .net for this pourpose?
Thanks

You need to write two (2) methods and install them on each end of your communications: A Send and a Receive.
A generic Send routine would send a message to some host listening on a given port number. Here is a simple example:
public static void Send(string message, string host, int port) {
if (!String.IsNullOrEmpty(message)) {
if (port < 80) {
port = DEF_PORT;
}
Byte[] data = Encoding.ASCII.GetBytes(message);
using (var client = new TcpClient(host, port)) {
var stream = client.GetStream();
stream.Write(data, 0, data.Length);
stream.Close();
client.Close();
}
}
}
A generic Receive routine would need to know the port number to listen on and should return the data that it receives. Here is a simple example of it:
public static string Receive(int port) {
string data = null;
listener = new TcpListener(IPAddress.Any, port);
listener.Start();
using (var client = listener.AcceptTcpClient()) { // waits until data is avaiable
int MAX = client.ReceiveBufferSize;
var stream = client.GetStream();
Byte[] buffer = new Byte[MAX];
int len = stream.Read(buffer, 0, MAX);
if (0 < len) {
data = Encoding.UTF8.GetString(buffer, 0, len);
}
stream.Close();
client.Close();
}
return data;
}
Here is the full class code that I used for this:
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Windows.Forms;
namespace AcpMobile5 {
class TestClass1 : Form {
public const int DEF_PORT = 8000;
private static TcpListener listener;
public static string Receive(int port) {
string data = null;
listener = new TcpListener(IPAddress.Any, port);
listener.Start();
using (var client = listener.AcceptTcpClient()) { // waits until data is avaiable
int MAX = client.ReceiveBufferSize;
var stream = client.GetStream();
Byte[] buffer = new Byte[MAX];
int len = stream.Read(buffer, 0, MAX);
if (0 < len) {
data = Encoding.UTF8.GetString(buffer, 0, len);
}
stream.Close();
client.Close();
}
return data;
}
public static void Send(string message, string host, int port) {
if (!String.IsNullOrEmpty(message)) {
if (port < 80) {
port = DEF_PORT;
}
Byte[] data = Encoding.ASCII.GetBytes(message);
using (var client = new TcpClient(host, port)) {
var stream = client.GetStream();
stream.Write(data, 0, data.Length);
stream.Close();
client.Close();
}
}
}
}
}

C# Connecting two tcp sockets together

I'm not sure if the title is all that informative.
I am trying to find/write a socket server that will accept a connection from the client (telnet) and then on behalf of the connected client, connect to one of four telnet servers inside the network.
Once connected I keep a counter of how many connections there are, and then if there are 4 total connections, disallow any new connections until one of the four is available.
I have written this:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net.Sockets;
using System.Threading;
using System.Net;
using System.IO;
namespace ConsoleApplication1
{
class Program
{
static int nodeCount = 4;
static int currentNode = 1;
static void Main(string[] args)
{
ServerProgram server = new ServerProgram();
}
class ServerProgram
{
private TcpListener tcpPrimaryListener;
private Thread listenThread;
public ServerProgram()
{
this.tcpPrimaryListener = new TcpListener(IPAddress.Any, 23);
Console.WriteLine("Telnet BBS Port Concentrator Server Started.");
Console.WriteLine("--------------------------------------------");
this.listenThread = new Thread(new ThreadStart(ListenForClients));
this.listenThread.Start();
}
private void ListenForClients()
{
this.tcpPrimaryListener.Start();
while (true)
{
TcpClient client = this.tcpPrimaryListener.AcceptTcpClient();
Thread clientThread = new Thread(new ParameterizedThreadStart(HandleClientComm));
clientThread.Start(client);
}
}
private void HandleClientComm(object client)
{
if (currentNode <= nodeCount)
{
Console.WriteLine("Connection thread created.");
StreamWriter swStream;
StreamWriter swStream2;
StreamReader srStream;
StreamReader srStream2;
TcpClient tcpClient = (TcpClient)client;
NetworkStream tcpClientStream = tcpClient.GetStream();
TcpClient telnet = new TcpClient("192.168.100.5" + currentNode, 23);
NetworkStream telnetStream = telnet.GetStream();
currentNode++;
while (true)
{
srStream = new StreamReader(tcpClient.GetStream());
swStream2 = new StreamWriter(tcpClient.GetStream());
srStream2 = new StreamReader(telnet.GetStream());
swStream = new StreamWriter(telnet.GetStream());
swStream.Write(srStream.ReadToEnd());
swStream2.Write(srStream2.ReadToEnd());
}
}
}
}
}
}
I've changed this example multiple times, so I don't really know anymore what I have and have not tried. I'm willing to try anything.
The purpose is actually running this to allow one telnet port open through the firewall, and allowing connections into a small network of DOS machines running telnet fossil driver BBS software. I would just like to redirect telnet traffic to an available system using only one port.
The problem is that I cannot figure out how to actually connect the two sockets together and pass data between them as it happens. The incoming socket and the socket I created on behalf of the server to the server.
Thanks.
UPDATE:
This is what is working for me, I'm still looking over for bugs but it's working so far.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net.Sockets;
using System.Threading;
using System.Net;
using System.IO;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
class Program
{
static int nodeCount = 2;
static int currentNode = 1;
static void Main(string[] args)
{
ServerProgram server = new ServerProgram();
}
class ServerProgram
{
private TcpListener tcpPrimaryListener;
private Thread listenThread;
public ServerProgram()
{
this.tcpPrimaryListener = new TcpListener(IPAddress.Any, 23);
Console.WriteLine("Telnet BBS Port Concentrator Server Started.");
Console.WriteLine("--------------------------------------------");
this.listenThread = new Thread(new ThreadStart(ListenForClients));
this.listenThread.Start();
}
private void ListenForClients()
{
this.tcpPrimaryListener.Start();
while (true)
{
TcpClient client = this.tcpPrimaryListener.AcceptTcpClient();
Thread clientThread = new Thread(new ParameterizedThreadStart(HandleClientComm));
clientThread.Start(client);
}
}
private void HandleClientComm(object client)
{
string noNodes = "Sorry all nodes are occupied.";
if (currentNode <= nodeCount)
{
Console.WriteLine("Client connected.");
TcpClient tcpClient = (TcpClient)client;
NetworkStream tcpClientStream = tcpClient.GetStream();
TcpClient telnet = new TcpClient("10.24.9.11", 23);
//TcpClient telnet = new TcpClient("192.168.100.5" + currentNode, 23);
NetworkStream telnetStream = telnet.GetStream();
currentNode++;
ByPass linkedSockets = new ByPass(tcpClientStream, telnetStream);
}
else
{
TcpClient tcpClient = (TcpClient)client;
NetworkStream tcpClientStream = tcpClient.GetStream();
ASCIIEncoding encoder = new ASCIIEncoding();
tcpClientStream.Write(Encoding.ASCII.GetBytes(noNodes), 0, noNodes.Length);
}
}
}
public class ByPass
{
public ByPass(Stream s1, Stream s2)
{
var cTokenSource = new CancellationTokenSource();
var cToken = cTokenSource.Token;
Task.Factory.StartNew(() => Process(s1, s2, cToken, cTokenSource), cToken);
Task.Factory.StartNew(() => Process(s2, s1, cToken, cTokenSource), cToken);
cToken.Register(() => cancelNotification());
}
public void Process(Stream s1, Stream s2, CancellationToken ct, CancellationTokenSource cTokenSource)
{
byte[] buf = new byte[0x10000];
while (true)
{
if (ct.IsCancellationRequested)
{
break;
}
try
{
int len = s1.Read(buf, 0, buf.Length);
s2.Write(buf, 0, len);
}
catch
{
s1.Close(); s2.Close();
cTokenSource.Cancel();
break;
}
}
}
}
static void cancelNotification()
{
Console.WriteLine("Client disconnected.");
currentNode--;
}
}
}

I think, you can create a class similar to below to pass data between two streams
public class ByPass
{
public ByPass(Stream s1, Stream s2)
{
Task.Factory.StartNew(() => Process(s1, s2));
Task.Factory.StartNew(() => Process(s2, s1));
}
public void Process(Stream sIn, Stream sOut)
{
byte[] buf = new byte[0x10000];
while (true)
{
int len = sIn.Read(buf, 0, buf.Length);
sOut.Write(buf, 0, len);
}
}
}

I have made little changes and it works perfect on my side
public class StreamTransmitter
{
static TaskCompletionSource<bool> ts;
public static async Task Start(Stream s1, Stream s2, CancellationToken token)
{
ts = new TaskCompletionSource<bool>();
Process(s1, s2, token);
Process(s2, s1, token);
await ts.Task;
}
private static async Task Process(Stream sIn, Stream sOut, CancellationToken token)
{
byte[] buf = new byte[0x10000];
int len = 0;
do
{
len = await sIn.ReadAsync(buf, 0, buf.Length, token);
await sOut.WriteAsync(buf, 0, len, token);
}
while (len > 0 && !token.IsCancellationRequested);
ts.SetResult(true);
}
}