public void Connect(string destination, ushort port)
{
SequenceNumber = (ushort)_client._rnd.Next(0, (int)ushort.MaxValue);
AcknowledgementNumber = 0;
Destination = destination;
DestinationPort = port;
OSI.Layer4TcpPacket packet = new OSI.Layer4TcpPacket();
packet.Destination = destination;
packet.RemotePort = port;
packet.LocalPort = SourcePort;
packet.SequenceNumber = SequenceNumber;
packet.AcknowledgementNumber = AcknowledgementNumber;
packet.SYN = true;
State = TcpState.SYN_SENT;
_client.SendPacket(packet);
DateTime now = DateTime.Now;
while ((DateTime.Now - now).TotalSeconds < TIMEOUT)
{
if (State == TcpState.ESTABLISHED)
{
return;
}
System.Threading.Thread.Sleep(25);
}
throw new Exception("TCP Timeout.");
}
public void SendPacket(TcpPacket packet)
{
try
{
OSI.Layer4TcpPacket l4 = new OSI.Layer4TcpPacket();
l4.PSH = true;
l4.ACK = true;
l4.RemotePort = DestinationPort;
l4.LocalPort = SourcePort;
l4.SequenceNumber = SequenceNumber;
l4.AcknowledgementNumber = AcknowledgementNumber;
l4.Destination = Destination;
int length = 0;
foreach (ILayer layer in packet.Layers)
{
length += layer.Length;
l4.NextLayers.Add(layer);
}
_client.SendPacket(l4);
SequenceNumber += (uint)length;
}
catch (Exception ex)
{
throw new Exception("No TCP Client is associated with this session.");
}
}
private void SendAck()
{
OSI.Layer4TcpPacket l4 = new OSI.Layer4TcpPacket();
l4.ACK = true;
l4.RemotePort = DestinationPort;
l4.LocalPort = SourcePort;
l4.SequenceNumber = SequenceNumber;
l4.AcknowledgementNumber = AcknowledgementNumber;
l4.Destination = Destination;
_client.SendPacket(l4);
}
private void SendTcpPacket(OSI.Layer4TcpPacket packet, PacketSentHandler callback)
{
TcpLayer tcpLayer =
new TcpLayer
{
SourcePort = packet.LocalPort,
DestinationPort = packet.RemotePort,
Checksum = null, // Will be filled automatically.
SequenceNumber = packet.SequenceNumber,
AcknowledgmentNumber = packet.AcknowledgementNumber,
Window = 64512,
};
if (packet.ACK)
{
tcpLayer.ControlBits = tcpLayer.ControlBits | TcpControlBits.Acknowledgment;
}
if (packet.SYN)
{
tcpLayer.ControlBits = tcpLayer.ControlBits | TcpControlBits.Synchronize;
}
if (packet.RST)
{
tcpLayer.ControlBits = tcpLayer.ControlBits | TcpControlBits.Reset;
}
if (packet.PSH)
{
tcpLayer.ControlBits = tcpLayer.ControlBits | TcpControlBits.Push;
}
if (packet.FIN)
{
tcpLayer.ControlBits = tcpLayer.ControlBits | TcpControlBits.Fin;
}
OSI.Layer3Packet l3 = new OSI.Layer3Packet();
l3.Ttl = 255;
l3.SourceIP = Configuration.IpAddress;
l3.Destination = packet.Destination;
foreach (ILayer layer in packet.NextLayers)
{
l3.NextLayers.Add(layer);
}
l3.NextLayers.Insert(0, tcpLayer);
SendLayer3Packet(l3, callback);
}
