private void ThreadMonitor()
{
while (m_theThread.IsAlive)
{
DateTime currentTime = DateTime.UtcNow;
DateTime lastActivityCopy;
TimeSpan timeSpan;
lock (lastActiveLock)
{
lastActivityCopy = m_lastActiveTime;
timeSpan = currentTime - m_lastActiveTime;
}
// has been idle for a long time
if ((timeSpan.TotalSeconds > m_maxIdleSeconds) && !m_theCommands.DataSocketOpen)
{
FtpServer.LogWrite($"closing connection {RemoteEndPoint} because of idle timeout; " +
$"last activity time: {lastActivityCopy}");
SocketHelpers.Send(m_theSocket,
$"426 No operations for {m_maxIdleSeconds}+ seconds. Bye!", m_theCommands.Encoding);
FtpServerMessageHandler.SendMessage(m_nId, "Connection closed for too long idle time.");
Stop();
return;
}
Thread.Sleep(1000 * m_maxIdleSeconds);
}
return; // only monitor the work thread
}
private void SendRejectMessage(TcpClient socket)
{
FtpServer.LogWrite(string.Format("{0} 421 Too many users now. Count {1}, Max {2}"
, socket.Client.ToString(), m_apConnections.Count, m_maxClients)
);
SocketHelpers.Send(socket, m_encoding.GetBytes("421 Too many users now\r\n"));
}
private void MonitorSafelly()
{
try
{
ThreadMonitor();
}
catch (Exception e)
{
FtpServer.LogWrite($"monitor thread for {RemoteEndPoint} failed: {e}");
}
}
private void SendRejectMessage(TcpClient socket)
{
lock (m_apConnections)
{
FtpServer.LogWrite(
$"{socket.Client.RemoteEndPoint} 421 Too many users now. Count {m_apConnections.Count}, Max {m_maxClients}"
);
string clientsDump = string.Join("\r\n", m_apConnections.Select(c => $"\t{c.RemoteEndPoint}"));
FtpServer.LogWrite($"connected clients:\r\n{clientsDump}");
SocketHelpers.Send(socket, m_encoding.GetBytes("421 Too many users now\r\n"));
}
}
private void RunSafelly()
{
try
{
ThreadRun();
}
catch (Exception e)
{
FtpServer.LogWrite($"socket handler thread for {RemoteEndPoint} failed: {e}");
}
finally
{
Closed?.Invoke(this);
}
}
private void InitialiseSocketHandler(TcpClient socket)
{
lock (m_apConnections)
{
var handler = new FtpSocketHandler(m_fileSystemClassFactory, m_nId);
handler.Closed += handler_Closed;
// get encoding for the socket connection
handler.Start(socket, m_encoding);
m_apConnections.Add(handler);
FtpServer.LogWrite(
$"Client accepted: {socket.Client.RemoteEndPoint} current count={m_apConnections.Count}");
Trace.WriteLine(
$"Handler created for client {handler.RemoteEndPoint}. Current Count {m_apConnections.Count}",
"Information");
NewConnection?.Invoke(m_nId);
}
}
public void Process(byte[] abData)
{
string sMessage = this.Encoding.GetString(abData);
// 2015-11-26 cljung : BUG .IndexOf returns -1 if search item isn't found. Substring throws exception with -1
int pos = sMessage.IndexOf('\r');
if (pos >= 0)
{
sMessage = sMessage.Substring(0, pos);
}
FtpServerMessageHandler.SendMessage(Id, sMessage);
string sCommand;
string sValue;
int nSpaceIndex = sMessage.IndexOf(' ');
if (nSpaceIndex < 0)
{
sCommand = sMessage.ToUpper();
sValue = "";
}
else
{
sCommand = sMessage.Substring(0, nSpaceIndex).ToUpper();
sValue = sMessage.Substring(sCommand.Length + 1);
}
// check whether the client has logged in
if (!isLogged)
{
if (!((sCommand == "USER") || (sCommand == "PASS") || (sCommand == "HELP") || (sCommand == "FEAT") || (sCommand == "QUIT")))
{
SocketHelpers.Send(Socket, "530 Not logged in\r\n", this.Encoding);
return;
}
}
// check if data connection will be used
if ((sCommand == "APPE") || (sCommand == "MLSD") || (sCommand == "LIST") || (sCommand == "RETR") || (sCommand == "STOR"))
{
m_useDataSocket = true;
}
var handler = m_theCommandHashTable[sCommand] as FtpCommandHandler;
if (handler == null)
{
FtpServerMessageHandler.SendMessage(Id, $"\"{sCommand}\" : Unknown command");
FtpServer.LogWrite($"{Socket.Client.RemoteEndPoint.ToString()} Unknown/unsupported command: {sCommand}");
SocketHelpers.Send(Socket, "550 Unknown command\r\n", this.Encoding);
}
else
{
handler.Process(sValue);
}
// reset
m_useDataSocket = false;
}
/// <summary>
/// The main thread of the ftp server
/// Listen and acception clients, create handler threads for each client
/// </summary>
private void ThreadRun()
{
FtpServerMessageHandler.Message += TraceMessage;
// listen at the port by the "FTP" endpoint setting
int port = int.Parse(ConfigurationManager.AppSettings["FTP"]);
System.Net.IPAddress ipaddr = SocketHelpers.GetLocalAddress();
System.Net.IPEndPoint ipEndPoint = new System.Net.IPEndPoint(ipaddr.Address, port);
FtpServer.m_ftpIpAddr = ipaddr.ToString();
m_socketListen = SocketHelpers.CreateTcpListener(ipEndPoint);
if (m_socketListen != null)
{
string msg = string.Format("FTP Server started.Listening to: {0}", ipEndPoint);
FtpServer.LogWrite(msg);
Trace.TraceInformation(msg);
m_socketListen.Start();
bool fContinue = true;
while (fContinue)
{
TcpClient socket = null;
try
{
socket = m_socketListen.AcceptTcpClient();
}
catch (SocketException)
{
fContinue = false;
}
finally
{
if (socket == null)
{
fContinue = false;
}
else if (m_apConnections.Count >= m_maxClients)
{
Trace.WriteLine("Too many clients, won't handle this connection", "Warnning");
SendRejectMessage(socket);
socket.Close();
}
else
{
socket.NoDelay = false;
m_nId++;
FtpServerMessageHandler.SendMessage(m_nId, "New connection");
SendAcceptMessage(socket);
// 2015-11-25 cljung : under stress testing, this happens. Don't know why yet, but let's keep it from crashing
try
{
InitialiseSocketHandler(socket);
}
catch (System.ObjectDisposedException ode)
{
Trace.TraceError(string.Format("ObjectDisposedException initializing client socket:\r\n{0}", ode));
m_nId--;
// can't fail
try {
socket.Close();
} catch { }
}
}
}
}
}
else
{
FtpServerMessageHandler.SendMessage(0, "Error in starting FTP server");
}
}