public static byte[] Serialize(this ITftpPacket packet)
{
MemoryStream bytes = new MemoryStream();
bytes.Write(EndianBitConverter.Big.GetBytes((ushort)packet.Op), 0, sizeof(ushort));
switch (packet.Op)
{
case TftpOperation.ReadRequest:
RrqPacket rrq = (RrqPacket)packet;
StringToNetascii(rrq.FileName, bytes);
StringToNetascii(rrq.Mode.ToString(), bytes);
break;
case TftpOperation.WriteRequest:
WrqPacket wrq = (WrqPacket)packet;
StringToNetascii(wrq.FileName, bytes);
StringToNetascii(wrq.Mode.ToString(), bytes);
break;
case TftpOperation.Data:
DataPacket data = (DataPacket)packet;
bytes.Write(EndianBitConverter.Big.GetBytes((ushort)data.BlockNumber), 0, sizeof(ushort));
bytes.Write(data.Data, 0, data.Data.Length);
break;
case TftpOperation.Ack:
AckPacket ack = (AckPacket)packet;
bytes.Write(EndianBitConverter.Big.GetBytes((ushort)ack.BlockNumber), 0, sizeof(ushort));
break;
case TftpOperation.Error:
ErrorPacket error = (ErrorPacket)packet;
bytes.Write(EndianBitConverter.Big.GetBytes((ushort)error.Error), 0, sizeof(ushort));
StringToNetascii(error.Message, bytes);
break;
default:
throw new Exception("Operation not recognized.");
}
return(bytes.ToArray());
}
public void Read(IPEndPoint server, string fileName, string outputPath, CancellationToken cancellationToken)
{
Console.WriteLine("Reading to local file '{0}' from file '{1}' on server {2}", outputPath, fileName, server);
using (FileStream outputFileStream = new FileStream(outputPath, FileMode.CreateNew, FileAccess.Write, FileShare.Read))
using (TftpConnection connection = new TftpConnection())
{
RemoteEndPointReservation remoteEPReservation = null;
try
{
bool initialized = false;
ushort currentBlockNumber = 1;
DataPacket currentDataPacket;
AckPacket ackPacket = null;
while (true)
{
Func <ITftpPacket, bool> receiveFilter = (ITftpPacket packet) =>
{
if (packet.Op == TftpOperation.Data)
{
DataPacket d = (DataPacket)packet;
if (d.BlockNumber == currentBlockNumber)
{
return(true);
}
else
{
Console.WriteLine("Incorrect DATA block number.");
}
}
else
{
Console.WriteLine("Incorrect operation. Expected DATA.");
}
return(false);
};
// To initialize the transfer, send RRQ and wait for the first data block.
if (!initialized)
{
Console.WriteLine("Sending RRQ");
// NOTE: the server only supports octet mode by design.
RrqPacket requestPacket = new RrqPacket(fileName, TftpMode.octet);
IPEndPoint remoteEP;
currentDataPacket = (DataPacket)connection.SendAndWaitForResponse(requestPacket, server, receiveFilter, out remoteEP, cancellationToken);
remoteEPReservation = new RemoteEndPointReservation(remoteEP);
connection.Connect(remoteEP);
initialized = true;
}
else
{
Console.WriteLine("Sending ack for block number {0}", ackPacket.BlockNumber);
currentDataPacket = (DataPacket)connection.SendAndWaitForResponse(ackPacket, receiveFilter, cancellationToken);
}
Console.WriteLine("DATA packet containing block {0} received", currentDataPacket.BlockNumber);
outputFileStream.Write(currentDataPacket.Data, 0, currentDataPacket.Data.Length);
ackPacket = new AckPacket(currentBlockNumber);
// When the received DATA packet is less than the maximum length, send a final ack and terminate.
if (currentDataPacket.Data.Length < DataPacket.MaxBlockSize)
{
connection.Send(ackPacket);
break;
}
++currentBlockNumber;
}
}
finally
{
if (remoteEPReservation != null)
{
remoteEPReservation.Dispose();
}
}
}
}
