public void WaitForSynAck()
{
EndPoint sender = (EndPoint)_endPoint;
var ackn = new byte[RPH.GetPacketByteLength()];
// set the timeout for receiving acks (retransmission timeout)
_sendingSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReceiveTimeout, Timeout);
try
{
_sendingSocket.ReceiveFrom(ackn, ref sender);
var rph = RPH.Deserialize(ackn);
if (IsCorrupt(rph) || !IsSynAck(rph))
{
_currentState = State.EstablishConnection;
return;
}
else
{
Console.WriteLine("Connection Established");
_currentState = State.SendPacket;
}
}
catch (SocketException e)
{
if (e.SocketErrorCode == SocketError.TimedOut)
{
Console.WriteLine(e.ToString());
Console.WriteLine("No Connection could be established");
}
_currentState = State.EstablishConnection;
}
}
private void WaitForAck()
{
EndPoint sender = (EndPoint)_endPoint;
var ackn = new byte[RPH.GetPacketByteLength()];
_tries++;
if (MaxRetransTries < _tries)
{
_currentState = State.FatalError;
return;
}
try
{
_sendingSocket.ReceiveFrom(ackn, ref sender);
var rph = RPH.Deserialize(ackn);
// Ack is corrupt
if (IsCorrupt(rph, ackn) || !IsAck(rph))
{
// If Ack is corrupt resend Packet
Console.WriteLine("Corrupt or NAck: Resend Packet");
}
else if (IsAck(rph) && !IsCorrupt(rph) && rph._ackNr != _localSeqNr)
{
_tries = 0;
Debug.Assert(rph != null, "rph != null");
_localSeqNr += _filechunk.Length;
_currentState = State.SendPacket;
}
else
{
Console.WriteLine("Not defined");
}
}
catch (SocketException e)
{
if (e.SocketErrorCode == SocketError.TimedOut)
{
// Timeout: Resend Packet
Console.WriteLine("Timeout: Resend Packet");
SendOnePacket();
}
else
{
Console.WriteLine("Fatal Error");
_currentState = State.FatalError;
return;
}
}
}
private void SendOnePacket()
{
int headSize = RPH.GetPacketByteLength();
byte[] packetBuf = null;
if (!IsLastPacket(PacketSizeBytes - headSize))
{
_filechunk = FileToChunk(_fileData, _localSeqNr, PacketSizeBytes - headSize);
packetBuf = new byte[PacketSizeBytes];
}
else
{
_filechunk = FileToChunk(_fileData, _localSeqNr, _fileData.Length - _localSeqNr);
packetBuf = new byte[_filechunk.Length + headSize];
_fileSend = true;
}
var rph = RPH.CreatePacketHeader(_localSeqNr, 0);
byte[] header = rph.Serialize();
// Copy together one packet: header with payload
Array.Copy(header, packetBuf, headSize);
Array.Copy(_filechunk, 0, packetBuf, headSize, _filechunk.Length);
// Last set the Checksum of the packet
SetChecksum(ref packetBuf);
// Now Send the packet
_sendingSocket.SendTo(packetBuf, _endPoint);
Console.WriteLine("Paket versendet");
// Change State
_currentState = State.WaitForAck;
}
