/// <summary>
/// Constructor
/// </summary>
/// <param name="parent">Parent view model</param>
public Abort(TransferProgress parent)
{
Parent = parent;
CanExecuteChanged?.Invoke(this, EventArgs.Empty);
}
/// <summary>
/// Actually do stuff
/// </summary>
/// <param name="UseExistingProgress">If a new progress bar should be created</param>
private void Work(bool UseExistingProgress = false)
{
if (!UseExistingProgress)
{
Progress = new TransferProgress
{
UserName = Receiver.Name,
UserPicture = Receiver.PicBytes,
FromOrTo = "to",
Parent = this
};
// Add new Progress Bar
Application.Current.Dispatcher.Invoke(() =>
{
((ObservableCollection <TransferProgress>)Application.Current.Properties["TransferProgresses"]).Insert(0, Progress);
});
}
// Check the file
if (!GetFileData())
{
return;
}
// Update the progress bar with the new data just obtained
Progress.FileName = FileName;
Progress.Maximum = FileSize;
// Don't even start transferring if user already cancelled
if (!MainCancellationToken.IsCancellationRequested)
{
// Set up the cancellation token
AbortTransfer = new CancellationTokenSource();
// Send File data
Response response = SendHello();
if (response != Response.ACCEPTED)
{
if (response == Response.REJECTED)
{
StopSending = true;
}
Progress.CurrentActivity = "Request rejected";
Progress.IsError = true;
return;
}
if (AbortTransfer.Token.IsCancellationRequested)
{
Progress.CurrentActivity = "Operation Cancelled.";
Progress.IsError = true;
// Useless, but just to keep things clean
StopSending = true;
return;
}
// If the main token (the one thrown by the main application) requests cancellation,
// then cancel the trasfer too.
using (CancellationTokenRegistration ctr = MainCancellationToken.Register(() => Cancel()))
{
//------------------------------------
// Load the file
//------------------------------------
Loader = Task.Run(() => { Load(); }, AbortTransfer.Token);
//------------------------------------
// Send the file
//------------------------------------
Sender = Task.Run(() => { Transmit(); }, AbortTransfer.Token);
Progress.CurrentActivity = "Transferring...";
// Wait for them to finish (Or that the user cancels them).
// NOTE: I can't wrap the Task definition in using(),
// because I need to wait for them to finish! I can't dispose them earlier!
Sender.Wait();
Loader.Wait();
// Dispose the tasks
Sender.Dispose();
Loader.Dispose();
if (!Progress.IsError)
{
Progress.CurrentActivity = "Transfer completed";
Progress.TextColor = "Green";
}
}
// Dispose it;
AbortTransfer.Dispose();
// Clean up
// If you're here, it means that the sender and loader have exited, so no need to lock.
Buffer.Clear();
}
}
/// <summary>
/// Parse the connection request
/// </summary>
/// <returns>True if request is valid, false if not.</returns>
/// <remarks>I should change this method, making it throw exceptions when something happens instead of
/// return bool. Remember this.</remarks>
public bool ParseHello()
{
//------------------------------------
// Init
//------------------------------------
int length = 0,
i = 0;
byte[] buffer;
try
{
// NOTE: I have no guarantees that I will read as much as I specified.
// In the first implementation, I was just doing something like Stream.Read(buffer,0,n),
// ignoring the fact that I could read less than n, trusting the fact that I was reading small data.
// Now, I am doing it like this to prevent such cases in which I read less than how much specified
Debug.WriteLine("------------------------");
Stream.ReadTimeout = 5 * 1000;
//------------------------------------
// The type of message
//------------------------------------
// Get the message
buffer = new byte[5];
while (i < 5)
{
i += Stream.Read(buffer, 0, 5 - i);
}
Debug.WriteLine("Received {0}", Encoding.UTF8.GetString(buffer));
// Parse the message type
string MessageType = Encoding.UTF8.GetString(buffer);
// ENDOC means that I don't want to send you anything else (= End the connection),
// so the return true is useless
if (MessageType.Equals("ENDOC"))
{
// Did I receive a ENDOC as very first message?
if (StopReceiving)
{
return(false);
}
StopReceiving = true;
return(true);
/**
* SECURITY IMPLICATIONS
*
* If an attacker spoofs their IP addres and sends ENDOC as very first message, this will
* stop the communication even before starting it. This is because this is not an authenticated protocol.
*
* POSSIBILE SOLUTIONS
*
* The ones listed in the HELLO below
**/
}
// If is not ENDOC and not even HELLO, then discard the packet.
// NOTE: the first time, when this return false, the communication will be instantly ended.
// But if you're sending a list of files, this will tell the sender to proceed with next file.
if (!MessageType.Equals("HELLO"))
{
return(false);
}
int isprivate = Stream.ReadByte();
if (isprivate == -1)
{
StopReceiving = true;
return(true);
}
// User is not private, but do I know who this is?
if (((byte)isprivate).Equals(1))
{
IPAddress ip = ((IPEndPoint)Client.Client.RemoteEndPoint).Address;
bool found = false;
ObservableCollection <User> users = (ObservableCollection <User>)Application.Current.Properties["Users"];
foreach (User u in users)
{
Debug.WriteLine("IP from remote endpoint: {0}, IP to check {1}", ip, u.IP);
if (u.IP.Equals(ip))
{
found = true;
SenderUser = new User(u);
break;
}
}
// Don't accept transfer if I don't know who this is.
// But what about private users? I don't know who they are either!
// Well, software's requirements say that private users don't communicate their existence,
// but can still send, so...
if (found == false)
{
Progress.CurrentActivity = "User not found";
Progress.IsError = true;
StopReceiving = true;
return(false);
}
}
else
{
if (((byte)isprivate).Equals(0))
{
SenderUser = null;
}
else
{
Progress.CurrentActivity = "Invalid request";
Progress.IsError = true;
// I don't understand your message...
StopReceiving = true;
return(false);
}
}
//------------------------------------
// The file name
//------------------------------------
// Get its length first
// At first, I used the set a fixed length of 200 bytes for file name,
// but wasn't sure if it would play nice with UNICODE. So I made it TLV-Style
buffer = new byte[4];
i = 0;
while (i < 4)
{
i += Stream.Read(buffer, 0, 4 - i);
}
length = BitConverter.ToInt32(buffer, 0);
// Name of files can be like: "file", "folder1/file", "folder1/folder2/file"
// So, it must be at least one byte long
if (length < 2)
{
return(false);
}
// Now get the name
buffer = new byte[length];
i = 0;
while (i < length)
{
i += Stream.Read(buffer, 0, length - i);
}
FileName = Encoding.Unicode.GetString(buffer).Trim('/').Trim('\0');
if (FileName.Length - FileName.Replace("/", "").Length > 0)
{
IsFolder = true;
}
Debug.WriteLine("Filename: {0}", FileName);
// Was wondering if there was a better method to count occurrences in a string than just looping it c-style.
// So I found this:
// https://stackoverflow.com/questions/541954/how-would-you-count-occurrences-of-a-string-within-a-string
//------------------------------------
// The file's extension
//------------------------------------
// Get its length
buffer = new byte[4];
i = 0;
while (i < 4)
{
i += Stream.Read(buffer, 0, 4 - i);
}
length = BitConverter.ToInt32(buffer, 0);
// Now get the actual extension
buffer = new byte[length];
i = 0;
while (i < length)
{
i += Stream.Read(buffer, 0, length - i);
}
FileExtension = Encoding.Unicode.GetString(buffer).Trim('\0');
Debug.WriteLine("Extension: {0}", FileExtension);
//------------------------------------
// Get the file size
//------------------------------------
buffer = new byte[8];
i = 0;
while (i < 8)
{
i += Stream.Read(buffer, 0, 8 - i);
}
FileSize = BitConverter.ToInt64(buffer, 0);
// Return true and don't stop receiving, meaning that the request is valid
StopReceiving = false;
Progress = new TransferProgress
{
Maximum = FileSize,
FileName = FileName,
UserName = SenderUser != null ? SenderUser.Name : "Private User",
UserPicture = SenderUser?.PicBytes,
FromOrTo = "from",
CurrentActivity = "Parsing Request...",
Parent = this
};
// Add new Progress Bar
Application.Current.Dispatcher.InvokeAsync(() =>
{
((ObservableCollection <TransferProgress>)Application.Current.Properties["TransferProgresses"]).Insert(0, Progress);
});
return(true);
}
catch (Exception)
{
return(false);
}
}
/// <summary>
/// Start transferring
/// </summary>
public override void Start()
{
// Before getting here, are there any errors?
if (SendType == PathType.UKNOWN)
{
return;
}
Worker = Task.Run(() =>
{
Progress = new TransferProgress
{
UserName = Receiver.Name,
UserPicture = Receiver.PicBytes,
FromOrTo = "to",
Parent = this
};
// Add new Progress Bar
Application.Current.Dispatcher.Invoke(() =>
{
((ObservableCollection <TransferProgress>)Application.Current.Properties["TransferProgresses"]).Insert(0, Progress);
});
using (Client = new TcpClient(AddressFamily.InterNetworkV6))
{
//------------------------------------
// Try To Connect
//------------------------------------
if (!Connect())
{
// Set Error Message as not responding
return;
}
//------------------------------------
// Send the "Hello" message
//------------------------------------
using (Stream = Client.GetStream())
{
Stream.Flush();
// At this point, I have already notified the receiver that I'm goin to send a directory.
// So from now on, I'm going to send files, not directories
SendType = PathType.FILE;
// Tells if you need to create a new progress bar
// The first time, you won't have to, but for subsequent files yes you do.
bool _progress = true;
// Loop through the files
foreach (string file in Files)
{
FilePath = file;
Work(_progress);
_progress = false;
if (StopSending)
{
break;
}
}
Stop();
} // Dispose the stream
Client.Close();
} // Dispose the client
});
Worker.Wait();
Worker.Dispose();
Worker = null;
}
