public bool Send(bool isdata)
{
//Apps.System.Debugger.debugger.Send("Sending TCP packet...");
if (isdata)
{
TCPPacket packet = new TCPPacket(source, dest, localPort, destPort, data, sequencenumber, acknowledgmentnb, 0x50, Flags, WSValue, 0x0000, false, false);
OutgoingBuffer.AddPacket(packet);
}
else
{
TCPPacket packet = new TCPPacket(source, dest, localPort, destPort, data, sequencenumber, acknowledgmentnb, 0x50, Flags, WSValue, 0x0000, true, true);
OutgoingBuffer.AddPacket(packet);
}
NetworkStack.Update();
//Apps.System.Debugger.debugger.Send("Sent!");
return(true);
}
public static bool CheckCRC(TCPPacket packet)
{
byte[] header = MakeHeader(packet.sourceIP.address, packet.destIP.address, packet.tcpLen, packet.sourcePort, packet.destPort, (uint)packet.sequencenumber, (uint)packet.acknowledgmentnb, packet.Headerlenght, packet.Flags, packet.WSValue, packet.UrgentPointer, packet.TCP_Data, false);
UInt16 calculatedcrc = Check(header, 0, header.Length);
//Apps.System.Debugger.debugger.Send("Calculated checksum: 0x" + Utils.Conversion.DecToHex(calculatedcrc));
//Apps.System.Debugger.debugger.Send("Received checksum : 0x" + Utils.Conversion.DecToHex(packet.Checksum));
if (calculatedcrc == packet.Checksum)
{
//Apps.System.Debugger.debugger.Send("checksum ok!!");
return true;
}
else
{
//Apps.System.Debugger.debugger.Send("checksum wrong!!");
return false;
}
}
internal static void TCPHandler(byte[] packetData)
{
TCPPacket tcp_packet = new TCPPacket(packetData);
if (Firewall.TCP.TCPIncomingFilter(tcp_packet))
{
//"=== [FIREWALL] TCP INCOMING PACKET BLOCKED " + tcp_packet.SourceIP.ToString() + ":" + tcp_packet.SourcePort.ToString() + " ===
return;
}
foreach (Drivers.NetworkDevice device in NetworkConfig.Keys)
{
if (device.Name == "PCNETII")
{
if (packetData.Length == 64 && tcp_packet.ipLength < 50)
{
byte[] rdata = tcp_packet.mRawData;
int lenght = 64 - (64 - (tcp_packet.ipLength + 14));
tcp_packet.tcpLen = (ushort)(lenght - 34);
tcp_packet.mRawData = new byte[lenght];
for (int b = 0; b <= lenght; b++)
{
tcp_packet.mRawData[b] = rdata[b];
}
}
}
if (device.Name == "RTL8168")
{
byte[] rdata = tcp_packet.mRawData;
int lenght = 64 - (64 - (tcp_packet.ipLength + 14));
tcp_packet.tcpLen = (ushort)(lenght - 34);
tcp_packet.mRawData = new byte[lenght];
for (int b = 0; b <= lenght; b++)
{
tcp_packet.mRawData[b] = rdata[b];
}
}
}
//=== Received TCP packet from " + tcp_packet.SourceIP.ToString() + ":" + tcp_packet.SourcePort.ToString() + " Len:" + tcp_packet.tcpLen.ToString() + "===
if (CheckCRC(tcp_packet))
{
bool SYN = (packetData[47] & (1 << 1)) != 0;
bool ACK = (packetData[47] & (1 << 4)) != 0;
bool FIN = (packetData[47] & (1 << 0)) != 0;
bool PSH = (packetData[47] & (1 << 3)) != 0;
bool RST = (packetData[47] & (1 << 2)) != 0;
ulong CID = tcp_packet.SourceIP.Hash + tcp_packet.sourcePort + tcp_packet.destPort;
TCPConnection.Connection connection = new TCPConnection.Connection();
if (SYN && !ACK)
{
//FLAG: SYN, New connection
if (TCPConnection.Connections.ContainsKey((uint)CID))
{
TCPConnection.Connections.Remove((uint)CID);
}
else
{
connection = new TCPConnection.Connection();
}
TCPConnection.Connections.Add((uint)CID, connection);
connection.CID = CID;
connection.dest = tcp_packet.sourceIP;
connection.source = tcp_packet.destIP;
connection.localPort = tcp_packet.destPort;
connection.destPort = tcp_packet.sourcePort;
connection.acknowledgmentnb = tcp_packet.sequencenumber + 1;
connection.WSValue = 1024;
connection.sequencenumber = 3455719727;
connection.Checksum = 0x0000;
connection.Flags = 0x12;
connection.Send(false);
connection.IsOpen = true;
return;
}
else if (SYN && ACK)
{
connection.dest = tcp_packet.sourceIP;
connection.source = tcp_packet.destIP;
connection.localPort = tcp_packet.destPort;
connection.destPort = tcp_packet.sourcePort;
connection.acknowledgmentnb = tcp_packet.sequencenumber + 1;
connection.WSValue = 1024;
connection.sequencenumber = tcp_packet.acknowledgmentnb;
connection.Checksum = 0x0000;
connection.Flags = 0x10;
connection.Send(false);
TCPClient.lastack = tcp_packet.sequencenumber + 1;
TCPClient.lastsn = tcp_packet.acknowledgmentnb;
TCPConnection.Connections[(uint)CID].IsOpen = true;
}
else if ((FIN || RST) && ACK && TCPConnection.Connections[(uint)CID].IsOpen)
{
//FLAG: FIN, ACK, Disconnected by host!!!
if (tcp_packet.sourcePort == 4224 && tcp_packet.destPort == 4224)
{
Console.WriteLine("Debugger closed by client computer!");
//Kernel.debugger.Stop();
}
connection.dest = tcp_packet.sourceIP;
connection.source = tcp_packet.destIP;
connection.localPort = tcp_packet.destPort;
connection.destPort = tcp_packet.sourcePort;
connection.acknowledgmentnb = tcp_packet.sequencenumber + 1;
connection.WSValue = 1024;
connection.sequencenumber = tcp_packet.acknowledgmentnb;
connection.Checksum = 0x0000;
connection.Flags = 0x10;
connection.Send(false);
connection.Flags = 0x11;
connection.Send(false);
connection.Close();
return;
}
else if (PSH && ACK && TCPConnection.Connections[(uint)CID].IsOpen)
{
//FLAG: PSH, ACK, Data received!? :D
TCPClient receiver = TCPClient.Client(tcp_packet.DestinationPort);
if (receiver != null)
{
receiver.receiveData(tcp_packet);
}
connection.dest = tcp_packet.sourceIP;
connection.source = tcp_packet.destIP;
connection.localPort = tcp_packet.destPort;
connection.destPort = tcp_packet.sourcePort;
connection.acknowledgmentnb = tcp_packet.sequencenumber + (ulong)tcp_packet.TCP_Data.Length;
connection.WSValue = 1024;
connection.sequencenumber = tcp_packet.acknowledgmentnb;
connection.Checksum = 0x0000;
connection.Flags = 0x10;
connection.Send(false);
connection.IsOpen = false;
return;
}
else if (RST && ACK)
{
//Apps.System.Debugger.debugger.Send("FLAG: RST, ACK, Port not listening on remote machine?");
return;
}
else if (RST)
{
//Apps.System.Debugger.debugger.Send("FLAG: RST, Connection aborted by host.");
return;
}
else if (ACK && TCPConnection.Connections[(uint)CID].IsOpen)
{
TCPClient.lastack = tcp_packet.sequencenumber;
TCPClient.lastsn = tcp_packet.acknowledgmentnb;
TCPClient.readytosend = true;
return;
}
else
{
//Apps.System.Debugger.debugger.Send("What is going wrong? D:");
}
}
else
{
//Apps.System.Debugger.debugger.Send("But checksum is incorrect... Packet Passed.");
TCPConnection.Connection connection = new TCPConnection.Connection();
connection.dest = tcp_packet.sourceIP;
connection.source = tcp_packet.destIP;
connection.localPort = tcp_packet.destPort;
connection.destPort = tcp_packet.sourcePort;
connection.acknowledgmentnb = 0x0000;
connection.WSValue = 1024;
connection.sequencenumber = tcp_packet.acknowledgmentnb;
connection.Checksum = 0x0000;
connection.Flags = 0x04;
connection.Send(false);
connection.Close();
return;
}
}