We Keep Coding

c# socket connection with multi threading telnet

**i use c# this code socket connection with multi threading **
i need set time out to my socket connection telnet
string ip = "";
int port = 23;
string str = "";
IPAddress address = IPAddress.Parse(ip);
IPEndPoint ipEndPoint = new IPEndPoint(address, port);
Socket socket = new Socket(address.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
socket.Connect((EndPoint)ipEndPoint);
try
{
byte[] numArray = new byte[1024];
while (socket.Connected) {
int count = socket.Receive(numArray);
str += Encoding.ASCII.GetString(numArray, 0, count);
Console.WriteLine(str);
}
socket.Close();
}
catch (ArgumentNullException ex)
{
}

You can either create a timer to do this or what I like to do is give the socket.connected a timeframe and base my connection of that. You'd obviously need to modify the time per your conditions, but this example has worked for me in the past.
Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
// Connect using a timeout (5 seconds)
IAsyncResult result = socket.BeginConnect( iP, iPort, null, null );
bool success = result.AsyncWaitHandle.WaitOne( 5000, true );
if ( socket.Connected )
{
socket.EndConnect( result );
}
else
{
//Be sure to close socket
socket.Close();
throw new ApplicationException("Failed to connect the server. Try again.");
}
I saw another example someone else did with timer, but I have not personally used this, so whichever you are more comfortable with. start a timer (timer_connection), if time is up, check whether socket connection is connected (if(m_clientSocket.Connected)), if not, pop up timeout error
private void connect(string ipAdd,string port)
{
try
{
SocketAsyncEventArgs e=new SocketAsyncEventArgs();
m_clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPAddress ip = IPAddress.Parse(serverIp);
int iPortNo = System.Convert.ToInt16(serverPort);
IPEndPoint ipEnd = new IPEndPoint(ip, iPortNo);
//m_clientSocket.
e.RemoteEndPoint = ipEnd;
e.UserToken = m_clientSocket;
e.Completed+=new EventHandler<SocketAsyncEventArgs>(e_Completed);
m_clientSocket.ConnectAsync(e);
if (timer_connection != null)
{
timer_connection.Dispose();
}
else
{
timer_connection = new Timer();
}
timer_connection.Interval = 2000;
timer_connection.Tick+=new EventHandler(timer_connection_Tick);
timer_connection.Start();
}
catch (SocketException se)
{
lb_connectStatus.Text = "Connection Failed";
MessageBox.Show(se.Message);
}
}
private void e_Completed(object sender,SocketAsyncEventArgs e)
{
lb_connectStatus.Text = "Connection Established";
WaitForServerData();
}
private void timer_connection_Tick(object sender, EventArgs e)
{
if (!m_clientSocket.Connected)
{
MessageBox.Show("Connection Timeout");
//m_clientSocket = null;
timer_connection.Stop();
}
}

Socket not receiving messages

When I use "127.0.0.1" on the same computer, it works just fine. If I try to use the server's public ip address, it doesn't work (actually I get a socket error). If I make it ipaddress.any it doesn't give an error, but it doesn't work, either. I thought maybe it's because I'm on the same computer, so I put the server on my desktop and client on my laptop, and I connected my laptop to my phone's hotspot so the ipaddress is different. It still doesn't work. The message gets sent, but never received. What am I doing wrong?
struct DataPacket
{
public IPEndPoint destination;
public byte[] data;
public DataPacket(IPEndPoint destination, byte[] data)
{
this.destination = destination;
this.data = data;
}
}
AsyncPriorityQueue<DataPacket> queuedReceiveData = new AsyncPriorityQueue<DataPacket>(NetworkConstants.MAX_PLAYERS_PER_SERVER, false);
Socket sck;
IPEndPoint ipEndPoint;
bool listening = true;
bool processing = true;
void Start()
{
sck = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
#if SERVER
ipEndPoint = new IPEndPoint(IPAddress.Any, NetworkConstants.SERVER_PORT);
sck.Bind(ipEndPoint);
#else
ipEndPoint = new IPEndPoint(IPAddress.Parse(NetworkConstants.SERVER_IP), NetworkConstants.SERVER_PORT);
EndPoint ep = new IPEndPoint(IPAddress.Any, 0); // doesn't work at all
//EndPoint ep = new IPEndPoint(IPAddress.Parse(NetworkConstants.SERVER_IP), 0); // says requested address is not valid in its context
//EndPoint ep = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 0); // works only on same computer
sck.Bind(ep);
#endif
new Thread(() => ListenForData()).Start();
new Thread(() => ProcessData()).Start();
#if !SERVER
SerializeCompact.BitStream bs = new SerializeCompact.BitStream();
bs.Write(Headers.Connect, minHeader, maxHeader);
SendData(bs.GetByteArray());
#endif
}
void OnDestroy()
{
listening = false;
processing = false;
sck.Close();
}
public void SendData(byte[] data)
{
var packet = queuedSendData.Dequeue();
sck.SendTo(data, 0, data.Length, SocketFlags.None, ipEndPoint);
print("message sent to server");
}
public void SendDataTo(byte[] data, IPEndPoint endPoint)
{
var packet = queuedSendData.Dequeue();
sck.SendTo(data, 0, data.Length, SocketFlags.None, endPoint);
print("message sent to client");
}
void ListenForData()
{
while (listening)
{
EndPoint endPoint = ipEndPoint;
byte[] buffer = new byte[1024];
int rec = sck.ReceiveFrom(buffer, 0, buffer.Length, SocketFlags.None, ref endPoint);
Array.Resize(ref buffer, rec);
queuedReceiveData.Enqueue(new DataPacket((IPEndPoint) endPoint, buffer), 0);
print("received message");
ProcessData(buffer);
}
}
void ProcessData()
{
while (processing)
{
var rcv = queuedReceiveData.Dequeue(); // blocks until an item can be dequeued
byte[] data = rcv.data;
IPEndPoint ep = rcv.destination;
// process data...
}
}

C# sync socket exception on receive method: System.Net.Sockets.SocketException

Please see code below, it is not very stable in my windows service, after starting for a while, it throw the error:
System.Net.Sockets.SocketException: the connected party did not
properly respond after a period of time, or established connection
failed because connected host has failed to respond
The error was catched on : readsize = listensocket2.Receive(buffer_receive);
The project is on a data communication center, the clients are GPRS DTU socket client.
Please help!!!
Part I:
protected override void OnStart(string[] args)
{
IPEndPoint endpoint = new IPEndPoint(RemsSocket.myip, RemsSocket.webport);
Socket listensocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
listensocket.Bind(endpoint);
listensocket.Listen(200);
Thread th = new Thread(new ParameterizedThreadStart(RemsSocket.listen_send));
th.IsBackground = true;
th.Start(listensocket);
}
Part II:
public static void listen_send(object source)
{
while (true)
{
done.Reset();
Socket listensocket = (Socket)source;
listensocket.BeginAccept(new AsyncCallback(acceptcallback_send), listensocket);
done.WaitOne();
}
}
public static void acceptcallback_send(IAsyncResult ar)
{
done.Set();
Socket socket = (Socket)ar.AsyncState;
Socket listensocket2 = socket.EndAccept(ar);
byte[] buffer_validate = new byte[buffersize];
string hostcode = "";
byte[] buffer_send = Hex.HexStringToByteArray(validate_code);
listensocket2.Send(buffer_send, 0, buffer_send.Length, SocketFlags.None);
listensocket2.Receive(buffer_validate);
int readsize = buffer_validate.Length; //listensocket2.EndReceive(ar);
if (readsize > 0)
{
bool success = FirstValidate(buffer_validate, ref hostcode);
bool validate = BLL.ExtHostBLL.CanCommunicate(hostcode);
if (success && validate)
{
LoopSendReceive(hostcode, listensocket2);
}
}
}
Part III:
public static void LoopSendReceive(string hostcode, Socket listensocket2)
{
listensocket2.Blocking = true;
byte[] buffer_receive = new byte[buffersize];
bool validate = BLL.ExtHostBLL.CanCommunicate(hostcode);
while (validate)
{
Thread.Sleep(500);
int readsize;
bool success;
IPEndPoint clientipe = (IPEndPoint)listensocket2.RemoteEndPoint;
byte commandByte = Hex.HexStringToByteArray(command_8);
listensocket2.Send(commandByte, 0, commandByte.Length, SocketFlags.None);
listensocket2.ReceiveTimeout = 5000;
int countSocketException = 0;
readsize = listensocket2.Receive(buffer_receive);
if (readsize != 0)
{
clientipe = (IPEndPoint)listensocket2.RemoteEndPoint;
ClientDto client = hostList.FirstOrDefault(c => c.Ip == clientipe.Address.ToString());
ParseChannel.AlertStatus[] data;
ParseChannel channel = new ParseChannel();
success = channel.Parse(buffer_receive, client, out data);
if (!success)
{
continue;
}
SaveData(data, client);
}
}
}

Send text file directly to network printer

I have currently-working code which sends raw data to a printer by writing a temporary file, then using File.Copy() to send it to the printer. File.Copy() supports both local ports, like LPT1 and shared printers like \\FRONTCOUNTER\LabelPrinter.
However, now I'm trying to get it working with a printer that's directly on the network: 192.168.2.100, and I can't figure out the format to use.
File.Copy(filename, #"LPT1", true); // Works, on the FRONTCOUNTER computer
File.Copy(filename, #"\\FRONTCOUNTER\LabelPrinter", true); // Works from any computer
File.Copy(filename, #"\\192.168.2.100", true); // New printer, Does not work
I know it's possible to "Add a printer" from each computer, but I'm hoping to avoid that - the second line of code above works from any computer on the network automatically, with no configuration required. I also know it's possible to P/Invoke the windows print spooler, and if that's my only option I may take it, but that's much more code overhead than I'd like to have.
Ideally, someone will have either a way to make File.Copy() work or a similar C# statement which will accept a network IP.

You can use sockets and send the data straight to that IP address. Should pretty much be the same as File.Copy. I just tried it out and that worked.
I just sent some text but here is the code that I used
Socket clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
clientSocket.NoDelay = true;
IPAddress ip = IPAddress.Parse("192.168.192.6");
IPEndPoint ipep = new IPEndPoint(ip, 9100);
clientSocket.Connect(ipep);
byte[] fileBytes = File.ReadAllBytes("test.txt");
clientSocket.Send(fileBytes);
clientSocket.Close();

try this code:
public class PrintHelper
{
private readonly IPAddress PrinterIPAddress;
private readonly byte[] FileData;
private readonly int PortNumber;
private ManualResetEvent connectDoneEvent { get; set; }
private ManualResetEvent sendDoneEvent { get; set; }
public PrintHelper(byte[] fileData, string printerIPAddress, int portNumber = 9100)
{
FileData = fileData;
PortNumber = portNumber;
if (!IPAddress.TryParse(printerIPAddress, out PrinterIPAddress))
throw new Exception("Wrong IP Address!");
}
public PrintHelper(byte[] fileData, IPAddress printerIPAddress, int portNumber = 9100)
{
FileData = fileData;
PortNumber = portNumber;
PrinterIPAddress = printerIPAddress;
}
/// <inheritDoc />
public bool PrintData()
{
//this line is Optional for checking before send data
if (!NetworkHelper.CheckIPAddressAndPortNumber(PrinterIPAddress, PortNumber))
return false;
IPEndPoint remoteEP = new IPEndPoint(PrinterIPAddress, PortNumber);
Socket client = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
client.NoDelay = true;
connectDoneEvent = new ManualResetEvent(false);
sendDoneEvent = new ManualResetEvent(false);
try
{
client.BeginConnect(remoteEP, new AsyncCallback(connectCallback), client);
connectDoneEvent.WaitOne();
client.BeginSend(FileData, 0, FileData.Length, 0, new AsyncCallback(sendCallback), client);
sendDoneEvent.WaitOne();
return true;
}
catch
{
return false;
}
finally
{
// Shutdown the client
this.shutDownClient(client);
}
}
private void connectCallback(IAsyncResult ar)
{
// Retrieve the socket from the state object.
Socket client = (Socket)ar.AsyncState;
// Complete the connection.
client.EndConnect(ar);
// Signal that the connection has been made.
connectDoneEvent.Set();
}
private void sendCallback(IAsyncResult ar)
{
// Retrieve the socket from the state object.
Socket client = (Socket)ar.AsyncState;
// Complete sending the data to the remote device.
int bytesSent = client.EndSend(ar);
// Signal that all bytes have been sent.
sendDoneEvent.Set();
}
private void shutDownClient(Socket client)
{
client.Shutdown(SocketShutdown.Both);
client.Close();
}
}
Network Helper class:
public static class NetworkHelper
{
public static bool CheckIPAddressAndPortNumber(IPAddress ipAddress, int portNumber)
{
return PingIPAddress(ipAddress) && CheckPortNumber(ipAddress, portNumber);
}
public static bool PingIPAddress(IPAddress iPAddress)
{
var ping = new Ping();
PingReply pingReply = ping.Send(iPAddress);
if (pingReply.Status == IPStatus.Success)
{
//Server is alive
return true;
}
else
return false;
}
public static bool CheckPortNumber(IPAddress iPAddress, int portNumber)
{
var retVal = false;
try
{
using (TcpClient tcpClient = new TcpClient())
{
tcpClient.Connect(iPAddress, portNumber);
retVal = tcpClient.Connected;
tcpClient.Close();
}
return retVal;
}
catch (Exception)
{
return retVal;
}
}
}

C# UDP Server/Client - NAT

Iam trying to send a message (via UDP) from my client to my server. The server should answer this message and if the client receives this answer he should print out a message.
If i run the client and server on my local network everything works fine.
If i try to connect through the internet from another PC outside my network the server receives the request of the client, sends an answer back, but the client never receives this answer. The client and the server are both behind a NAT but i portforwarded the ports at the server´s NAT and the server got its own DNS. I already tried NAT traversal but it gives me the same IP and port adress as the IPEndPoint of the server, after receiveing the request of the client, does.
I´ve got no idea how to fix this, so any guidance would be much appreciated.
Client
public static void Main()
{
Thread receiveThread = new Thread(new ThreadStart(ReceiveData));
receiveThread.Start();
object[] oData = {1};
sendData(oData, 0,0, "Li");
while (true)
{
Console.ReadLine();
}
}
private void receiveData()
{
string receivePort = 8080;
Socket client = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
client.ReceiveTimeout = 1000;
IPEndPoint end = new IPEndPoint(IPAddress.Any, receivePort);
client.Bind(end);
while (true)
{
try
{
byte[] data = new byte[1024];
client.Receive(data, 0, data.Length, SocketFlags.None);
object[] receivedObj = Deserialize(data);
string sType = (string)receivedObj[3];
if (sType == "Li")
{
console.WriteLine("received Li");
}
}
catch (Exception err)
{
Console.WriteLine(err.ToString());
}
}
}
public static void sendData(object[] oData, int iFrom, int iTo, string sType)
{
string sendPort = 17171;
UdpClient client = new UdpClient();
string IP = "ThisIsTheDNSofmyServer.com"; //ServerDNS
//string IP = "192.168.xxx.xxx"; //serverIP in LAN
if (IP.StartsWith("T"))
{
IP = (Dns.GetHostAddresses(IP))[0].ToString();
}
IPEndPoint remoteEndPoint = new IPEndPoint(IPAddress.Parse(IP), sendPort);
oData[1] = iFrom;
oData[2] = iTo;
oData[3] = sType;
Byte[] data = Serialize(oData);
client.Send(data, data.Length, remoteEndPoint);
}
The server´s code is almost the same:
public static void Main()
{
Thread receiveThread = new Thread(new ThreadStart(ReceiveData));
receiveThread.Start();
while (true)
{
Console.ReadLine();
}
}
private static void ReceiveData()
{
int receivePort = 17171;
UdpClient client = new UdpClient(receivePort);
while (true)
{
try
{
IPEndPoint anyIP = new IPEndPoint(IPAddress.Any, 0);
byte[] data = new byte[1024];
data = client.Receive(ref anyIP);
object[] receivedObj = Deserialize(data);
//if I receive data send an Answer
sendData(receivedObj, 0,0,"Li",anyIP.Address.ToString());
}
catch (Exception err)
{
Console.WriteLine(err.ToString());
}
}
}
private static void sendData(object[] oData, int iFrom, int iTo, string sType, string IP)
{
int sendPort = 8080;
object[] paket = { oData, iFrom, iTo, sType };
UdpClient client = new UdpClient();
IPEndPoint remoteEndPoint = new IPEndPoint(IPAddress.Parse(IP), sendPort);
client.Send(data, data.Length, remoteEndPoint);
}

i believe this is a port cofniguration issue,
8080 is almost likely to be configured as alternate http
"The UdpClient you use to receive datagrams must be created using the multicast port number" from MSDN
Hope this helps and good luck
Krishna

You do not need to do anything unordinary to traverse NAT in the setup you described, you just need to send it from the server back to your client; specifically: you must send back to the end point, i.e. IP and port, you received it on.
client.Send(data, data.Length, remoteEndPoint); // remoteEndPoint is the IPEndPoint you got the datagram on