internal TCPSegment GetTCPSyncSegment()
{
SeqNumber = (uint)R.Next();
_initSeqNumber = SeqNumber;
// 1st step handshake
TCPSegment tcpSyncSegment = new TCPSegment(PuertoOrigen, PuertoDestino, null, 0);
tcpSyncSegment.SYN_Flag = true;
tcpSyncSegment.SEQ_Number = SeqNumber;
return tcpSyncSegment;
}
internal List<TCPSegment> ProcesarSegmento(TCPSegment segmentoOrigen)
{
List<TCPSegment> segmentos = new List<TCPSegment>();
/// 2ns setp hand shacke
if (segmentoOrigen.SYN_Flag &&
!segmentoOrigen.ACK_Flag &&
segmentoOrigen.DataLength == 0)
{
SeqNumber = (uint)R.Next();
ACKNumber = segmentoOrigen.SEQ_Number + 1;
TCPSegment segmentoRetorno = new TCPSegment(PuertoOrigen, PuertoDestino, null, 0);
segmentoRetorno.SYN_Flag = true;
segmentoRetorno.ACK_Flag = true;
segmentoRetorno.SEQ_Number = SeqNumber;
segmentoRetorno.ACK_Number = ACKNumber;
segmentos.Add(segmentoRetorno);
return segmentos;
}
// 3rd step hand shake server
if (segmentoOrigen.ACK_Flag &&
!segmentoOrigen.FinFlag &&
!segmentoOrigen.SYN_Flag &&
segmentoOrigen.ACK_Number == SeqNumber + 1 &&
!_fin &&
(segmentoOrigen.DataLength == 0))
{
SeqNumber = segmentoOrigen.ACK_Number;
SegmentSize = segmentoOrigen.SegmentSize;
return segmentos;
}
/// Transferencia
if (segmentoOrigen.ACK_Flag &&
!segmentoOrigen.FinFlag &&
segmentoOrigen.ACK_Number == SeqNumber &&
segmentoOrigen.SEQ_Number == ACKNumber&&
(segmentoOrigen.DataLength != 0))
{
SegmentSize = segmentoOrigen.DataLength;
ACKNumber = segmentoOrigen.SEQ_Number + (uint)SegmentSize + 1;
TCPSegment segmentoRetorno = new TCPSegment(PuertoOrigen, PuertoDestino, null, 0);
segmentoRetorno.ACK_Flag = true;
segmentoRetorno.SEQ_Number = SeqNumber;
segmentoRetorno.ACK_Number = ACKNumber;
segmentos.Add(segmentoRetorno);
return segmentos;
}
/// Fin ACK
if (segmentoOrigen.ACK_Flag &&
segmentoOrigen.FinFlag &&
segmentoOrigen.ACK_Number == SeqNumber &&
segmentoOrigen.SEQ_Number == ACKNumber + segmentoOrigen.DataLength &&
(segmentoOrigen.DataLength == 0))
{
ACKNumber = segmentoOrigen.SEQ_Number + 1;
SeqNumber = segmentoOrigen.ACK_Number;
TCPSegment segmentoACK_FIN = new TCPSegment(PuertoOrigen, PuertoDestino, null, 0);
segmentoACK_FIN.ACK_Flag = true;
segmentoACK_FIN.SEQ_Number = SeqNumber;
segmentoACK_FIN.ACK_Number = ACKNumber;
segmentos.Add(segmentoACK_FIN);
TCPSegment segmentoFIN = new TCPSegment(PuertoOrigen, PuertoDestino, null, 0);
segmentoFIN.ACK_Flag = true;
segmentoFIN.FinFlag = true;
segmentoFIN.SEQ_Number = SeqNumber;
segmentoFIN.ACK_Number = ACKNumber;
segmentos.Add(segmentoFIN);
_fin = true;
return segmentos;
}
if (segmentoOrigen.ACK_Flag &&
!segmentoOrigen.FinFlag &&
segmentoOrigen.ACK_Number == SeqNumber +1&&
segmentoOrigen.SEQ_Number == ACKNumber &&
_fin &&
(segmentoOrigen.DataLength == 0))
{
Data = segmentoOrigen.Data;
FileName = segmentoOrigen.FileName;
if (ArchivoRecibido != null)
{
ArchivoRecibido(this, new EventArgs());
}
}
return segmentos;
}
public List<TCPSegment> ProcesarSegmento(TCPSegment segmentoOrigen)
{
List<TCPSegment> segmentos = new List<TCPSegment>();
// 3rd setp handshake
if (segmentoOrigen.SYN_Flag &&
segmentoOrigen.ACK_Flag &&
!segmentoOrigen.FinFlag &&
segmentoOrigen.DataLength == 0 &&
SeqNumber - _initSeqNumber != Data.Length &&
segmentoOrigen.ACK_Number == SeqNumber + 1)
{
ACKNumber = segmentoOrigen.SEQ_Number + 1;
SeqNumber = segmentoOrigen.ACK_Number;
TCPSegment segmentoRetorno = new TCPSegment(PuertoOrigen, PuertoDestino, null, 0);
segmentoRetorno.ACK_Flag = true;
segmentoRetorno.SEQ_Number = SeqNumber;
segmentoRetorno.ACK_Number = ACKNumber;
segmentoRetorno.SegmentSize = SegmentSize;
segmentos.Add(segmentoRetorno);
TCPSegment segmentoprimerDato = new TCPSegment(PuertoOrigen, PuertoDestino, null, SegmentSize);
segmentoprimerDato.ACK_Flag = true;
segmentoprimerDato.SEQ_Number = SeqNumber;
segmentoprimerDato.ACK_Number = ACKNumber;
segmentos.Add(segmentoprimerDato);
return segmentos;
}
if (!segmentoOrigen.SYN_Flag &&
segmentoOrigen.ACK_Flag &&
segmentoOrigen.FinFlag &&
segmentoOrigen.DataLength == 0 &&
SeqNumber - _initSeqNumber -2== Data.Length &&
segmentoOrigen.ACK_Number == SeqNumber + 1)
{
ACKNumber = segmentoOrigen.SEQ_Number + 1;
SeqNumber = segmentoOrigen.ACK_Number;
TCPSegment segmentoRetorno = new TCPSegment(PuertoOrigen, PuertoDestino, Data, 0);
segmentoRetorno.FileName = FileName;
segmentoRetorno.ACK_Flag = true;
segmentoRetorno.SEQ_Number = SeqNumber;
segmentoRetorno.ACK_Number = ACKNumber;
segmentos.Add(segmentoRetorno);
if (FinComunicacion != null)
FinComunicacion(this, new EventArgs());
Console.WriteLine("fin host");
return segmentos;
}
// Data Transfer
if (!segmentoOrigen.SYN_Flag &&
segmentoOrigen.ACK_Flag &&
!segmentoOrigen.FinFlag &&
segmentoOrigen.ACK_Number == SeqNumber + SegmentSize + 1 &&
SeqNumber - _initSeqNumber != Data.Length &&
segmentoOrigen.DataLength == 0)
{
SeqNumber = segmentoOrigen.ACK_Number;
int bytesTransmited = (int)SeqNumber - (int)_initSeqNumber - 1;
if (bytesTransmited >= Data.Length)
{
segmentos.Add(GetFinRequest());
return segmentos;
}
TCPSegment segmentoRetorno = new TCPSegment(PuertoOrigen, PuertoDestino, null, SegmentSize);
segmentoRetorno.ACK_Flag = true;
segmentoRetorno.SEQ_Number = SeqNumber;
segmentoRetorno.ACK_Number = ACKNumber;
int segmentSize = SegmentSize;
if (Data.Length - bytesTransmited < SegmentSize)
{
segmentSize = Data.Length - bytesTransmited;
segmentoRetorno.Data = Data;
}
SegmentSize = segmentSize;
segmentoRetorno.DataLength = SegmentSize;
segmentos.Add(segmentoRetorno);
return segmentos;
}
return segmentos;
}
internal TCPSegment GetPrimerSegmentoStream()
{
TCPSegment segmento = new TCPSegment(PuertoOrigen, PuertoDestino, null, SegmentSize);
segmento.ACK_Flag = true;
segmento.SEQ_Number = SeqNumber;
segmento.ACK_Number = ACKNumber;
segmento.DataLength = SegmentSize;
return segmento;
}
private TCPSegment GetFinRequest()
{
TCPSegment tcpFInSegment = new TCPSegment(PuertoOrigen, PuertoDestino, null, 0);
tcpFInSegment.FinFlag = true;
tcpFInSegment.ACK_Flag = true;
SeqNumber = SeqNumber;
tcpFInSegment.SEQ_Number = SeqNumber;
tcpFInSegment.ACK_Number = ACKNumber;
return tcpFInSegment;
}