bool UpdateSession(byte[] image)
{
// update the session duration
using (var command = new OleDbCommand(Program.Settings.CommandUpdateDuration, connection))
{
command.Parameters.AddWithValue("@Duration", (int)((DateTime.Now - sessionStart).TotalMinutes));
command.Parameters.AddWithValue("@Session", session);
if (command.ExecuteNonQuery() != 1)
{
return(false);
}
}
// update the screenshot
using (var command = new OleDbCommand(Program.Settings.CommandUpdateScreenshot, connection))
{
command.Parameters.AddWithValue("@Screenshot", (object)image ?? DBNull.Value);
command.Parameters.AddWithValue("@Session", session);
try { command.ExecuteNonQuery(); }
catch (OleDbException e) { ServiceApplication.LogEvent(EventLogEntryType.Warning, e.Message); }
}
// return success
return(true);
}
void HandleRequest(object state)
{
// try to logon the user and create the response
var request = (Request)state;
int timeout;
try { timeout = LogonAndCreateSession(request.UserName, request.Password, request.Address); }
catch (OleDbException e)
{
ServiceApplication.LogEvent(EventLogEntryType.Error, e.Message);
return;
}
var response = new RadiusPacket(timeout < 0 ? PacketCode.AccessReject : PacketCode.AccessAccept);
response.Identifier = request.Identifier;
if (timeout > 0)
{
response.Attribute(RadiusAttribute.SessionTimeout).Add(timeout);
}
response.Attribute(RadiusAttribute.ProxyState).AddRange(request.ProxyStates);
response.SignResponse(request.Authenticator, sharedSecred);
try { socket.SendTo(response.GetBuffer(), 0, response.Length, SocketFlags.None, request.Client); }
catch (ObjectDisposedException) { }
catch (SocketException e) { ServiceApplication.LogEvent(EventLogEntryType.Error, e.Message); }
}
bool System.ServiceModel.Dispatcher.IErrorHandler.HandleError(Exception error)
{
// ignore expected fault exceptions and log all other types
if (!(error is FaultException))
{
ServiceApplication.LogEvent(EventLogEntryType.Error, error.Message);
}
return(false);
}
public bool Continue(Stream image)
{
// check the input argument and the state of the session
if (image == null)
{
throw new ArgumentNullException("image").AsFault();
}
if (disposed)
{
throw new ObjectDisposedException(ToString()).AsFault();
}
if (!ready)
{
new InvalidOperationException().AsFault();
}
try
{
// ensure that the user is still allowed to logon
using (var command = new OleDbCommand(Program.Settings.CommandVerifyLogin, connection))
{
command.Parameters.AddWithValue("@ID", id);
command.Parameters.AddWithValue("@State", state);
if (!Convert.ToBoolean(command.ExecuteScalar()))
{
return(false);
}
}
// load, adjust and store the screenshot and update the duration
using (var screenshot = LoadImageFromStream(image))
using (var zoomed = screenshot.Zoom(Program.Settings.ScreenshotSize.Width, Program.Settings.ScreenshotSize.Height, Program.Settings.ScreenshotFormat))
return(UpdateSession(zoomed.ToOleObject(progId: "Screenshot", dde: "Screenshot", modifiable: false)));
}
catch (OleDbException e)
{
// keep the session going as long as allowed
if (databaseErrors++ < Program.Settings.DatabaseIgnoreUpdateErrors)
{
ServiceApplication.LogEvent(EventLogEntryType.Error, e.Message);
return(true);
}
// otherwise rethrow the error
throw;
}
}
static void CleanupScreenshots(object state)
{
// clean up all out-of-date screenshots
try
{
using (var connection = new OleDbConnection(Program.Settings.Database))
{
connection.Open();
using (var command = new OleDbCommand(Program.Settings.CommandCleanupScreenshots, connection))
{
command.Parameters.AddWithValue("@Interval", Program.Settings.ScreenshotCleanupInterval.TotalSeconds);
command.ExecuteNonQuery();
}
}
}
catch (OleDbException e) { ServiceApplication.LogEvent(EventLogEntryType.Warning, e.Message); }
}
void Listener()
{
// create the buffer and start listening
var buffer = new byte[0x10000];
while (true)
{
// receive the next message
var endpoint = (EndPoint) new IPEndPoint(IPAddress.Any, 0);
var length = socket.ReceiveFrom(buffer, ref endpoint);
// if nothing is received, continue listening
if (length == 0)
{
continue;
}
// parse the packet and retrieve all necessary attributes
var request = new Request();
request.Client = (IPEndPoint)endpoint;
try
{
var packet = new RadiusPacket(buffer, length);
if (packet.Code != PacketCode.AccessRequest)
{
continue;
}
request.Identifier = packet.Identifier;
request.Authenticator = packet.Authenticator;
if (packet.Attribute(RadiusAttribute.CHAPPassword).Count > 0)
{
throw new FormatException("CHAP-Password is not supported");
}
var userNames = packet.Attribute(RadiusAttribute.UserName);
if (userNames.Count != 1)
{
throw new FormatException("User-Name is not present");
}
request.UserName = userNames[0];
if (packet.Attribute(RadiusAttribute.UserPassword).Count != 1)
{
throw new FormatException("User-Password is not present");
}
request.Password = packet.GetUserPassword(sharedSecred);
var callerIds = packet.Attribute(RadiusAttribute.CallingStationId);
request.Address = callerIds.Count > 0 ? callerIds[0] : null;
request.ProxyStates = packet.Attribute(RadiusAttribute.ProxyState).ToArray();
}
#if DEBUG
catch (FormatException e)
{
ServiceApplication.LogEvent(EventLogEntryType.Information, e.Message);
continue;
}
#else
catch (FormatException) { continue; }
#endif
// enqueue the request
ThreadPool.QueueUserWorkItem(HandleRequest, request);
}
}
