/// <summary>
/// Used Post-Exchange to setup a file transfer from the remote host
/// </summary>
///
/// <param name="PacketStream">The stream containing the file transfer request</param>
private void ReceiveFile(Stream PacketStream)
{
// asynchronous transfer by sending a file key and info, and running the entire transfer on another socket..
if (!_isEstablished)
throw new CryptoProcessingException("DtmKex:ReceiveFile", "The VPN has not been established!", new InvalidOperationException());
if (FileRequest == null)
throw new CryptoProcessingException("DtmKex:ReceiveFile", "The FileRequest and FileReceived must be connected to perform a file transfer, read the documentation!", new InvalidOperationException());
if (FileReceived == null)
throw new CryptoProcessingException("DtmKex:ReceiveFile", "The FileRequest and FileReceived must be connected to perform a file transfer, read the documentation!", new InvalidOperationException());
// get the header
DtmPacket pktHdr = new DtmPacket(PacketStream);
// read the packet
byte[] enc = new byte[pktHdr.PayloadLength];
// get the encrypted data
PacketStream.Read(enc, 0, enc.Length);
// decrypt it using client crypto processor
byte[] dec = SymmetricTransform(_cltSymProcessor, enc);
// remove padding
dec = UnwrapMessage(dec);
MemoryStream pktStm = new MemoryStream(dec);
// get file info header
DtmFileInfo pktFi = new DtmFileInfo(pktStm);
// get the key
KeyParams fileKey = KeyParams.DeSerialize(pktStm);
// forward request to app
DtmFileRequestEventArgs args = new DtmFileRequestEventArgs(pktFi.FileName);
FileRequest(this, args);
// accept file or refuse and exit; app must send back a valid path or cancel; if cancel, send a refuse notice which will signal the end of the transfer, otherwise store file path and port
if (args.Cancel || string.IsNullOrEmpty(args.FilePath) || args.FilePath.Equals(pktFi.FileName) || !Directory.Exists(Path.GetDirectoryName(args.FilePath)))
{
// send refuse and exit
Transmit(DtmPacketTypes.Transfer, (short)DtmTransferFlags.Refused, pktHdr.OptionFlag);
}
else
{
// create the files crypto processor
ICipherMode fileSymProcessor = SymmetricInit(_cltIdentity.Session, fileKey);
// enable parallel decryption
int blockSize = ((int)MessageBufferSize - DtmPacket.GetHeaderSize()) - ((int)MessageBufferSize - DtmPacket.GetHeaderSize()) % ((CTR)fileSymProcessor).ParallelMinimumSize;
((CTR)fileSymProcessor).ParallelBlockSize = blockSize;
// init the file transfer host
DtmFileTransfer fileTransfer = new DtmFileTransfer(fileSymProcessor, pktHdr.OptionFlag, 1024, (int)FileBufferSize);
fileTransfer.FileTransferred += new DtmFileTransfer.FileTransferredDelegate(OnFileReceived);
fileTransfer.ProgressPercent += new DtmFileTransfer.ProgressDelegate(OnFileReceivedProgress);
// add to dictionary
_transQueue.TryAdd(pktHdr.OptionFlag, fileTransfer);
try
{
// start the transfer on a new thread
Task socketTask = Task.Factory.StartNew(() =>
{
fileTransfer.StartReceive(_clientSocket.RemoteAddress, (int)pktFi.OptionsFlag, args.FilePath);
});
socketTask.Wait(10);
}
catch (AggregateException ae)
{
if (SessionError != null)
SessionError(this, new DtmErrorEventArgs(ae.GetBaseException(), DtmErrorSeverity.Warning));
}
}
}
private void OnFileRequest(object owner, DtmFileRequestEventArgs args)
{
// set the args.Cancel to true to refuse a file
//args.Cancel = true;
// get the file name
string fileName = args.FilePath;
// if accept, prepend the destination directory and set the path
args.FilePath = Path.Combine(@"C:\Tests\Saved\Test", fileName);
}