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

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);
}
}
}

Related

TcpClient connected but server not receiving message

Server :
public class TcpServer
{
private TcpListener tcpListener;
private static ManualResetEvent allDone = new ManualResetEvent(false);
public TcpServer(string url, int port)
{
tcpListener = new TcpListener(IPAddress.Parse(url), port);
pingMapper = new LightPingMapper();
}
public void Run()
{
tcpListener.Start();
Console.WriteLine("Server running");
while (true)
{
allDone.Reset();
tcpListener.BeginAcceptSocket(AcceptCallback, tcpListener);
Console.WriteLine("Accepting socket");
allDone.WaitOne();
}
Console.ReadLine();
}
private void AcceptCallback(IAsyncResult result)
{
try
{
allDone.Set();
var listener = (TcpListener) result.AsyncState;
var handler = listener.EndAcceptSocket(result);
StateObject state = new StateObject();
state.workSocket = handler;
handler.BeginReceive(state.buffer, 0, state.buffer.Length, 0, ReadCallback, state);
}
catch (Exception e)
{
Console.WriteLine($"Error accepting callback. {e.Message}");
}
}
private void ReadCallback(IAsyncResult asyncResult)
{
try
{
string content = string.Empty;
Console.WriteLine("Read data from socket");
StateObject state = (StateObject) asyncResult.AsyncState;
Socket handler = state.workSocket;
int bytesRead = handler.EndReceive(asyncResult);
if (bytesRead > 0)
{
state.sb.Append(Encoding.UTF8.GetString(state.buffer));
content = state.sb.ToString();
Console.WriteLine(content + " " + DateTime.Now);
}
}
catch (Exception e)
{
Console.WriteLine($"Error reading socket. {e.Message}");
}
}
}
class StateObject
{
// Client socket.
public Socket workSocket = null;
// Size of receive buffer.
public const int BufferSize = 256;
// Receive buffer.
public byte[] buffer = new byte[BufferSize];
// Received data string.
public StringBuilder sb = new StringBuilder();
}
Client:
public class TCPClientWrapper
{
private TcpClient tcpClient;
private readonly string address;
private readonly int port;
public TCPClientWrapper(string address, int port)
{
InitTcpClient();
this.address = address;
this.port = port;
}
public void SendMessage()
{
for(int i=0; i < 10; i++)
{
if (!SocketConnected())
{
TryConnect();
}
byte[] buffer = Encoding.UTF8.GetBytes("Hello");
tcpClient.Client.Send(buffer);
Thread.Sleep(60000);
}
}
private void TryConnect()
{
bool isConnected = false;
while (true)
{
try
{
InitTcpClient();
tcpClient.Connect(IPAddress.Parse(address), port);
if (SocketConnected())
{
Console.WriteLine("TcpClient, Connected");
isConnected = true;
break;
}
}
catch (Exception e)
{
Console.WriteLine("TcpClient, connection failed. Try to reconnect after 30 seconds, {0}", e.Message);
}
finally
{
if (!isConnected)
{
tcpClient.Close();
Thread.Sleep(30000);
}
}
}
}
private void InitTcpClient()
{
tcpClient = new TcpClient();
tcpClient.SendTimeout = 15;
}
private bool SocketConnected()
{
var s = tcpClient.Client;
if (!s.Connected)
return false;
bool part1 = s.Poll(1000, SelectMode.SelectRead);
bool part2 = s.Available == 0;
return !(part1 && part2);
}
}
The problem is that server read only first message , each next message is not received by server . The tcpClient is connected , but server doesn't receive any message . Could anyone suggest what is wrong with my code ?
In ReadCallback, you don't start the next read - so yes, your code only reads once.
Adding
handler.BeginReceive(state.buffer, 0, state.buffer.Length, 0, ReadCallback, state);
to the bottom of ReadCallback (when bytesRead > 0) should work. However! You aren't implementing proper framing, so you should be very cautious of that. A basic framing implementation for a text-based protocol (like this) would be to use some kind of line-end sentinel, and buffer data until you see a line-end, then process the line.
On TCP, you are only guaranteed to get the right bytes in the right order (or a failed socket eventually) - you are not guaranteed to get them in the same composition in terms of calls to Send exactly matching calls to Receive in terms of the numbers of bytes in each.

Client And Server Socket Connection using C#

I created two projects one with client and other with server to exchange text between both of them;on same computer i run those exe.
MY Client Side Connection Code connection looked :
using (SocketClient sa = new SocketClient(host, port))
{
sa.Connect();
Console.WriteLine(sa.SendReceive("Message #" + i.ToString()));
}
sa.Disconnect();
while socketclient is my class which contain these methods and constructor:
internal SocketClient(String hostName, Int32 port)
{
IPHostEntry host = Dns.GetHostEntry(hostName);
IPAddress[] addressList = host.AddressList;
this.hostEndPoint = new IPEndPoint(addressList[addressList.Length - 1], port);
this.clientSocket = new Socket(this.hostEndPoint.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
}
internal void Connect()
{
SocketAsyncEventArgs connectArgs = new SocketAsyncEventArgs();
connectArgs.UserToken = this.clientSocket;
connectArgs.RemoteEndPoint = this.hostEndPoint;
connectArgs.Completed += new EventHandler<SocketAsyncEventArgs>(OnConnect);
clientSocket.ConnectAsync(connectArgs);
autoConnectEvent.WaitOne();
SocketError errorCode = connectArgs.SocketError;
if (errorCode != SocketError.Success)
{
throw new SocketException((Int32)errorCode);
}
}
internal void Disconnect()
{
clientSocket.Disconnect(false);
}
private void OnConnect(object sender, SocketAsyncEventArgs e)
{
autoConnectEvent.Set();
this.connected = (e.SocketError == SocketError.Success);
}
internal String SendReceive(String message)
{
if (this.connected)
{
Byte[] sendBuffer = Encoding.ASCII.GetBytes(message);
SocketAsyncEventArgs completeArgs = new SocketAsyncEventArgs();
completeArgs.SetBuffer(sendBuffer, 0, sendBuffer.Length);
completeArgs.UserToken = this.clientSocket;
completeArgs.RemoteEndPoint = this.hostEndPoint;
completeArgs.Completed += new EventHandler<SocketAsyncEventArgs>(OnSend);
clientSocket.SendAsync(completeArgs);
AutoResetEvent.WaitAll(autoSendReceiveEvents);
return Encoding.ASCII.GetString(completeArgs.Buffer, completeArgs.Offset,completeArgs.BytesTransferred);
}
else
{
throw new SocketException((Int32)SocketError.NotConnected);
}
}
while on server side code looks like that:
SocketListener sl = new SocketListener(numConnections, bufferSize);
sl.Start(port);
Console.WriteLine("Server listening on port {0}.
Press any key to terminate the server process...", port);
Console.Read();
sl.Stop();
Socket listener is my class which contain this method and constructor :
internal SocketListener(Int32 numConnections, Int32 bufferSize)
{
this.numConnectedSockets = 0;
this.numConnections = numConnections;
this.bufferSize = bufferSize;
this.readWritePool = new SocketAsyncEventArgsPool(numConnections);
this.semaphoreAcceptedClients = new Semaphore(numConnections, numConnections);
for (Int32 i = 0; i < this.numConnections; i++)
{
SocketAsyncEventArgs readWriteEventArg = new SocketAsyncEventArgs();
readWriteEventArg.Completed += new EventHandler<SocketAsyncEventArgs> (OnIOCompleted);
readWriteEventArg.SetBuffer(new Byte[this.bufferSize], 0, this.bufferSize);
this.readWritePool.Push(readWriteEventArg);
}
}
internal void Start(Int32 port)
{
IPAddress[] addressList = Dns.GetHostEntry(Environment.MachineName).AddressList;
IPEndPoint localEndPoint = new IPEndPoint(addressList[addressList.Length - 1], port);
this.listenSocket = new Socket(localEndPoint.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
this.listenSocket.ReceiveBufferSize = this.bufferSize;
this.listenSocket.SendBufferSize = this.bufferSize;
if (localEndPoint.AddressFamily == AddressFamily.InterNetworkV6)
{
this.listenSocket.SetSocketOption(SocketOptionLevel.IPv6, (SocketOptionName)27, false);
this.listenSocket.Bind(new IPEndPoint(IPAddress.IPv6Any, localEndPoint.Port));
}
else
{
this.listenSocket.Bind(localEndPoint);
}
this.listenSocket.Listen(this.numConnections);
this.StartAccept(null);
mutex.WaitOne();
}
I have already port forward of my router because of server side exe which didn't listen without port forwarding.
it is working fine with send and receive on same pc and same port at home.
While when i try to run both of codes exe on my office computer it throws exception at following line:
Exception thrown by socket
Could any one guide me whats the problem and how to resolve it ?
Thanks
Have you tried temporary disable your Windows firewall ?

C# socket read buffer error with multiple clients connecting to servers

I write an Windows C# application which can create up to 16 threads. Each thread creates a socket for a remote device. Each thread send commands to read the device status. (every 300 ms) It is OK when I create one or two threads to read the status. But when I create 10 threads to read device status, I will get wrong data in the socket receive buffer.
Please refer to the following for my socket driver code:
class SocketClient {
private IPAddress ipAddress;
private IPEndPoint remoteEP;
private Socket mSocket;
private SocketAsyncEventArgs e = new SocketAsyncEventArgs();
private System.Timers.Timer timer_connection;
private static byte[] response = new byte[1024];
private Boolean waittingConnectDone;
private Boolean boolConnected;
public SocketClient() {
}
private byte[] acknowledge = null;
public Boolean Connect(String IP, int Port) {
Boolean bRet = true;
ipAddress = IPAddress.Parse(IP);
remoteEP = new IPEndPoint(ipAddress, Port);
mSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
//mSocket.ReceiveTimeout = GlobalVar.ethernet_timeout;
mSocket.ReceiveTimeout = 500;
try {
waittingConnectDone = false;
e.RemoteEndPoint = remoteEP;
e.UserToken = mSocket;
e.Completed += new EventHandler<SocketAsyncEventArgs>(e_Completed);
mSocket.ConnectAsync(e);
if (timer_connection != null) {
timer_connection.Dispose();
} else {
timer_connection = new System.Timers.Timer();
}
timer_connection.Interval = 2000;
timer_connection.Elapsed += new ElapsedEventHandler(timer_connection_Tick);
timer_connection.Start();
while (true) {
if (waittingConnectDone)
break;
Application.DoEvents();
}
bRet = boolConnected;
//sender.Connect(remoteEP);
} catch {
Debug.WriteLine("### Ethernet ### Connection Error!");
bRet = false;
}
return bRet;
}
private void e_Completed(object sender, SocketAsyncEventArgs e) {
boolConnected = true;
waittingConnectDone = true;
}
private void timer_connection_Tick(object sender, EventArgs e) {
if (!mSocket.Connected) {
timer_connection.Stop();
boolConnected = false;
waittingConnectDone = true;
}
}
public void Disconnect() {
try {
mSocket.Shutdown(SocketShutdown.Both);
mSocket.Close();
} catch {
}
}
Each Thread use following code to read the device status:
private byte[] acknowledge = null;
private static byte[] response = new byte[1024];
public byte[] sendCommand(byte[] Cmp_TxData) {
try {
bytesSent = mSocket.Send(Cmp_TxData);
bytesRec = mSocket.Receive(response);
acknowledge = new byte[bytesRec];
Array.Copy(response, 0, acknowledge, 0, bytesRec);
}
catch
{
acknowledge = null;
}
return acknowledge;
}
And the buffer data error is something like following:
TX --> 00-03-01-F4-00-03-44-14
RX <-- 00-00-00-00-00-00-00-00-00-00-00
Sometime I read correct data, but sometimes the data are all 0!
Is there anything wrong with my socket driver?
Really appreciate your help!!
I have not checked all of the posted code (I suspect there may be more errors, multithreading is hard if you try to do it all yourself), but this line:
private static byte[] response = new byte[1024];
Is definitely a source for the types of errors you report. This line declares a buffer that is shared between all threads.
So if multiple threads do this:
bytesRec = mSocket.Receive(response);
The data in this response buffer can be concurrently modified.
To resolve this specific error, you could ensure that you create a static buffer for each thread using [ThreadStatic] or ThreadLocal (see for example http://reedcopsey.com/2009/11/12/thread-specific-data-becomes-easier-in-net-4-0-via-threadlocalt/).

.NET Sockets suddenly stopped working

I wrote a TCP Socket server and client a few months ago in my current project and they've been working flawlessly since then. But as of today I simply cannot get a connection between two machines that has been communicating without a hickup for a long time.
The setup is very straight forward: Two machines ('A' and 'B') are connected directly via an ethernet cable (no switch in between). Machine 'A' is also connected to my home network which allows for Internet access. Machine 'B' is only connected to 'A'. I am running the TCP server on 'B' and the client on 'A'.
I'm using the asynchronous .NET Socket features (BeginAccept etc on the server end and BeginConnect etc in the client end). Having debugged both ends I can only confirm that the server end never seems to get a call from the client. I haven't touched the code and it still works between other machines.
Also, there's no other comms problems between the two machines. I'm using Input Director to share one set of keyboard/mouse and normal UNC paths works fine to browse one machine from the other.
I have tested different ports and I've brought down the firewalls on both sides for good measure. I have released/renewed the connections on both sides, rebooted both machines and every other dummy option I can think of.
I confess I'm not terribly network savvy so I'd very much appreciate a few hints on what to look for next as I'm now out of ideas on what to check next. (I'm pretty sure it's gotta be something really stupid I've just overlooked. ;O)
EDIT (sample 'spike' code)
On request I adapted Microsoft's sample Socket code and compressed it a bit (below). I then tested running both server and client ends on machine 'B' which worked fine but on machine 'A' the same thing happened. The client got no contact with the server end. Here's the code:
public static class SocketServer
{
private class StateObject
{
public Socket _workSocket;
public const int BufferSize = 1024;
public readonly byte[] _buffer = new byte[BufferSize];
public readonly StringBuilder _sb = new StringBuilder();
}
private static readonly ManualResetEvent _s_allDone = new ManualResetEvent(false);
public static void StartListening()
{
var ipHostInfo = Dns.Resolve(Dns.GetHostName());
var ipAddress = ipHostInfo.AddressList[0];
var localEndPoint = new IPEndPoint(ipAddress, 11000);
var listener = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
try
{
listener.Bind(localEndPoint);
listener.Listen(100);
while (true)
{
_s_allDone.Reset();
Console.WriteLine("Waiting for a connection...");
listener.BeginAccept(acceptCallback, listener);
_s_allDone.WaitOne();
}
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
Console.WriteLine("\nPress ENTER to continue...");
Console.Read();
}
private static void acceptCallback(IAsyncResult ar)
{
_s_allDone.Set();
var listener = (Socket)ar.AsyncState;
var handler = listener.EndAccept(ar);
var state = new StateObject {_workSocket = handler};
handler.BeginReceive(state._buffer, 0, StateObject.BufferSize, 0, readCallback, state);
}
private static void readCallback(IAsyncResult ar)
{
var state = (StateObject)ar.AsyncState;
var handler = state._workSocket;
int bytesRead = handler.EndReceive(ar);
if (bytesRead <= 0)
return;
state._sb.Append(Encoding.ASCII.GetString(state._buffer, 0, bytesRead));
var content = state._sb.ToString();
if (content.IndexOf("<EOF>") > -1)
{
Console.WriteLine("Read {0} bytes from socket. \n Data : {1}", content.Length, content);
}
else
{
handler.BeginReceive(state._buffer, 0, StateObject.BufferSize, 0, readCallback, state);
}
}
public static int Main(String[] args)
{
StartListening();
return 0;
}
}
public static class SocketClient
{
private class StateObject
{
public Socket _workSocket;
public const int BufferSize = 256;
public readonly byte[] _receiveBuffer = new byte[BufferSize];
public readonly StringBuilder _sb = new StringBuilder();
}
private const int RemotePort = 11000;
private static readonly ManualResetEvent _s_connectDone = new ManualResetEvent(false);
private static readonly ManualResetEvent _s_sendDone = new ManualResetEvent(false);
private static readonly ManualResetEvent _s_receiveDone = new ManualResetEvent(false);
// The response from the remote device.
private static String _s_response = String.Empty;
private static void startClient()
{
try
{
_s_connectDone.WaitOne(2000); // <-- gives server time to boot when on same machine
var ipHostInfo = Dns.Resolve(Dns.GetHostName());
var ipAddress = ipHostInfo.AddressList[0];
var remoteEndPoint = new IPEndPoint(ipAddress, RemotePort);
var client = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
client.BeginConnect(remoteEndPoint, connectCallback, client);
_s_connectDone.WaitOne();
send(client, "This is a test<EOF>");
_s_sendDone.WaitOne();
receive(client);
_s_receiveDone.WaitOne();
Console.WriteLine("Response received : {0}", _s_response);
client.Shutdown(SocketShutdown.Both);
client.Close();
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
private static void connectCallback(IAsyncResult ar)
{
try
{
var client = (Socket)ar.AsyncState;
client.EndConnect(ar);
Console.WriteLine("Socket connected to {0}", client.RemoteEndPoint);
_s_connectDone.Set();
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
private static void receive(Socket client)
{
try
{
var state = new StateObject {_workSocket = client};
client.BeginReceive(state._receiveBuffer, 0, StateObject.BufferSize, 0, receiveCallback, state);
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
private static void receiveCallback(IAsyncResult ar)
{
try
{
var state = (StateObject)ar.AsyncState;
var client = state._workSocket;
var bytesRead = client.EndReceive(ar);
if (bytesRead > 0)
{
state._sb.Append(Encoding.ASCII.GetString(state._receiveBuffer, 0, bytesRead));
client.BeginReceive(state._receiveBuffer, 0, StateObject.BufferSize, 0, receiveCallback, state);
}
else
{
if (state._sb.Length > 1)
{
_s_response = state._sb.ToString();
}
_s_receiveDone.Set();
}
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
private static void send(Socket client, String data)
{
var byteData = Encoding.ASCII.GetBytes(data);
client.BeginSend(byteData, 0, byteData.Length, 0, sendCallback, client);
}
private static void sendCallback(IAsyncResult ar)
{
try
{
var client = (Socket)ar.AsyncState;
var bytesSent = client.EndSend(ar);
Console.WriteLine("Sent {0} bytes to server.", bytesSent);
_s_sendDone.Set();
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
public static int Main()
{
startClient();
return 0;
}
}

TCP server causes MAX CPU utlization

i write this TCP communication library. the problem is that. when a client connects. the CPU usages boosts to maximum....this causes other application to become slow...
please take a look at the code and correct me where i did wrong..
the main code of my TCP library is
TCP Server Class
public class TCPServerEndPoint : ICommunication
{
private string channelName;
private string localIP;
private int localPort;
private string remoteIP;
private int remotePort;
private TcpListener tcpListenter;
/// <summary>
/// Accept the incomming connection and pass it to a thread to handle communication.
/// </summary>
private TCPServerWorker worker;
/// <summary>
/// List of threads created for connected clients.
/// </summary>
List<TCPServerWorker> workerThreads;
/// <summary>
/// Thread to keep listening process in seperate thread.
/// </summary>
private Thread serverThread;
/// <summary>
/// Flag to keep status of Endpoint.
/// </summary>
private bool keepRunning;
public TCPServerEndPoint()
{
this.keepRunning = false;
Guid guid = Guid.NewGuid();
channelName = guid.ToString();
workerThreads = new List<TCPServerWorker>();
}
public TCPServerEndPoint(string localIP, int localPort, string remoteIP, int remotePort)
{
this.localIP = localIP;
this.localPort = localPort;
this.remoteIP = remoteIP;
this.remotePort = remotePort;
workerThreads = new List<TCPServerWorker>();
this.keepRunning = false;
}
public event EventHandler<CommEventArgs> OnCommReceive;
public int CommStart()
{
if (this.IsStarted == true)
{
Console.WriteLine("TCP Server is already running");
return -1;
}
serverThread = new Thread(new ThreadStart(StartListening));
serverThread.IsBackground = true;
serverThread.Start();
return 0;
}
private void StartListening()
{
try
{
IPAddress localAddress = IPAddress.Parse(this.localIP);
tcpListenter = new TcpListener(localAddress, this.localPort);
tcpListenter.Start();
Console.WriteLine("TCP Server started");
Console.WriteLine("Server is listening on port : {0}", this.localPort);
this.keepRunning = true;
// look for incomming connections
while (this.keepRunning)
{
// connection received
TcpClient client = tcpListenter.AcceptTcpClient();
// create a new WorkerThread and pass the connected client to handle.
worker = new TCPServerWorker(client);
worker.dataReceived += new EventHandler<CommEventArgs>(worker_dataReceived);
workerThreads.Add(worker);
worker.Start();
}
tcpListenter.Stop();
Console.WriteLine("TCP Server stopped");
this.keepRunning = false;
}
catch
{
return;
}
}
void worker_dataReceived(object sender, CommEventArgs e)
{
if (this.OnCommReceive != null)
{
e.commChannel = this;
this.OnCommReceive(this, e);
}
}
public int CommStop()
{
if (this.IsStarted == false)
return -1;
// Close all worker threads created for connected clients.
foreach (TCPServerWorker item in workerThreads)
{
item.KeepRunning = false;
}
// break the listening loop
this.keepRunning = false;
// clear the worker thread list
workerThreads.Clear();
// force server to receive message to break while(keepRunning) loop
byte[] data = new byte[4];
IPEndPoint ipEndPoint = new IPEndPoint(IPAddress.Parse(this.localIP), localPort);
Socket tcpClient = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
tcpClient.Connect(ipEndPoint);
tcpClient.SendTo(data, ipEndPoint);
tcpClient.Close();
return 0;
}
public int CommSend(CommEventArgs obj)
{
obj.destAddress = this.remoteIP;
obj.destPort = this.remotePort;
return CommSendTo(obj);
}
public int CommSendTo(CommEventArgs obj)
{
int n;
byte[] buf;
try
{
IPEndPoint ipEndPoint = new IPEndPoint(IPAddress.Parse(obj.destAddress), obj.destPort);
buf = (byte[])obj.data;
Socket tcpClient = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
tcpClient.Connect(ipEndPoint);
n = tcpClient.SendTo(buf, ipEndPoint);
tcpClient.Close();
}
catch (Exception ex)
{
Console.WriteLine("Exception :: {0}", ex.Message);
return -1;
}
if (n == buf.Length)
{
if (OnCommSendComplete != null)
{
OnCommSendComplete(this, obj);
}
Console.WriteLine("Sent {0} bytes to {1}:{2}", n, obj.destAddress, obj.destPort);
}
else
{
return -1;
}
return n;
}
}
}
TCPServerWorker.cs
class TCPServerWorker
{
private TcpClient client;
private bool keepRunning;
public event EventHandler<CommEventArgs> dataReceived;
private const int MAX_TCP_DATA = 64000;
public bool KeepRunning
{
get
{
return this.keepRunning;
}
set
{
this.keepRunning = value;
}
}
public TCPServerWorker(TcpClient client)
{
this.client = client;
this.keepRunning = false;
}
public void Start()
{
Thread thread = new Thread(new ThreadStart(Process));
thread.IsBackground = true;
thread.Start();
}
private void Process()
{
if (client.Connected == true)
{
Console.WriteLine("Client connected :: {0}", client.Client.RemoteEndPoint);
this.keepRunning = true;
while (this.keepRunning)
{
// in my view. here is the main problem. this loop run for infinite time and causes CPU to reach at 100
byte[] buffer = new byte[MAX_TCP_DATA];
NetworkStream stream = client.GetStream();
StreamWriter writer = new StreamWriter(client.GetStream());
if (stream.DataAvailable == true)
{
int receivedBytesCount = stream.Read(buffer, 0, buffer.Length);
byte[] receivedBuffer = new byte[receivedBytesCount];
Array.Copy(buffer, receivedBuffer, receivedBytesCount);
String msg = Encoding.UTF8.GetString(receivedBuffer);
Console.WriteLine("Received MSG ::: " + msg);
writer.WriteLine("Server : Received {0} bytes", receivedBytesCount);
CommEventArgs comEventArg = new CommEventArgs();
comEventArg.data = (byte[])receivedBuffer;
IPEndPoint remoteIPEndPoint = (IPEndPoint)client.Client.RemoteEndPoint;
comEventArg.srcAddress = remoteIPEndPoint.Address.ToString();
comEventArg.srcPort = remoteIPEndPoint.Port;
comEventArg.length = receivedBytesCount;
this.OnDataReceived(comEventArg);
writer.Flush();
}
}
client.Close();
}
}
protected void OnDataReceived(CommEventArgs e)
{
if (this.dataReceived != null)
{
this.dataReceived(this, e);
}
}
}
}
You're using nonblocking I/O which leads to a loop (at least) in your client
while (this.keepRunning) {...}
which is consuming all your CPU resources by busy waiting.
You should consider to use blocking I/O or Socket.Select
Look at the first remark here
Details about select
One thing to note is that you never SET IsStarted .. you only GET it ._. Maybe you're spawning hundreds of threads =/ I'm talking about the TCPServerEndPoint class =/
Yes, you are busy waiting for a connection. I don't know socket programming so I can't give you details, but what you need to do is wait for a connection using the blocking system call.
I solved the issue after modifying the Process method of TCPServerWorker.cs
here is the changes
private void Process()
{
if (client.Connected == true)
{
Console.WriteLine("Client connected :: {0}", client.Client.RemoteEndPoint);
Byte[] bytes = new Byte[MAX_TCP_DATA];
String data = null;
NetworkStream stream = client.GetStream();
int i;
try
{
// Loop to receive all the data sent by the client.
while ((i = stream.Read(bytes, 0, bytes.Length)) != 0)
{
// bytes contains received data in byte[].
// Translate data bytes to a UTF-8 string.
byte[] receivedBuffer = new byte[i];
Array.Copy(bytes, receivedBuffer, i);
data = System.Text.Encoding.UTF8.GetString(receivedBuffer);
Console.WriteLine("Received MSG ::: " + data);
// Process the data sent by the client.
byte[] msg = System.Text.Encoding.UTF8.GetBytes(data);
// Send back a response.
stream.Write(msg, 0, msg.Length);
CommEventArgs comEventArg = new CommEventArgs();
comEventArg.data = receivedBuffer;
IPEndPoint remoteIPEndPoint = (IPEndPoint)client.Client.RemoteEndPoint;
comEventArg.srcAddress = remoteIPEndPoint.Address.ToString();
comEventArg.srcPort = remoteIPEndPoint.Port;
comEventArg.length = i;
this.OnDataReceived(comEventArg);
}
}
catch (Exception ex)
{
Console.WriteLine("Exception : " + ex.Message);
}
finally
{
client.Close();
}
}
}

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