using System;
using System.IO;
using System.Runtime.InteropServices;
using System.Threading;
using Microsoft.Win32;
using System.Net;
using System.Net.Sockets;
using System.Text;


namespace TestProg
{
    // State object for receiving data from remote device.
    public class StateObject
    {
        // Client socket.
        public Socket workSocket = null;
        // Size of receive buffer.
        public const int BufferSize = 256;
        // Receive buffer.
        public byte[] buffer = new byte[BufferSize];
        // Received data string.
        public StringBuilder sb = new StringBuilder();
    }
    class Program
    {
        // The port number for the remote device.
        private const int port = 11000;

        // ManualResetEvent instances signal completion.
        private static ManualResetEvent connectDone =
            new ManualResetEvent(false);
        private static ManualResetEvent sendDone =
            new ManualResetEvent(false);
        private static ManualResetEvent receiveDone =
            new ManualResetEvent(false);

        // The response from the remote device.
        private static String response = String.Empty;

        static void Main(string[] args)
        {
            //----------------------------------------------
                            // Establish the remote endpoint for the socket.
                // The name of the 
                // remote device is "host.contoso.com".
                IPHostEntry ipHostInfo = Dns.Resolve("7.214.111.103");
                IPAddress ipAddress = ipHostInfo.AddressList[0];
                IPEndPoint remoteEP = new IPEndPoint(ipAddress, port);

                // Create a TCP/IP socket.
                Socket client = new Socket(AddressFamily.InterNetwork,
                    SocketType.Stream, ProtocolType.Tcp);

                // Connect to the remote endpoint.
                client.BeginConnect(remoteEP,
                    new AsyncCallback(ConnectCallback), client);
                connectDone.WaitOne();

            //AsynchronousClient client= new AsynchronousClient();
            //-----------------------------------------------
            const string UsermodeDeviceSpace = "\\\\.\\Global\\";
            string devGuid = GetDeviceGuid();
            Console.WriteLine(HumanName(devGuid));
            IntPtr ptr = CreateFile(UsermodeDeviceSpace + devGuid + ".tap", FileAccess.ReadWrite,
                FileShare.ReadWrite, 0, FileMode.Open, FILE_ATTRIBUTE_SYSTEM | FILE_FLAG_OVERLAPPED, IntPtr.Zero);
            int len;
            IntPtr pstatus = Marshal.AllocHGlobal(4);
            Marshal.WriteInt32(pstatus, 1);
            DeviceIoControl(ptr, TAP_CONTROL_CODE(6, METHOD_BUFFERED) /* TAP_IOCTL_SET_MEDIA_STATUS */, pstatus, 4,
                    pstatus, 4, out len, IntPtr.Zero);
            IntPtr ptun = Marshal.AllocHGlobal(12);
            Marshal.WriteInt32(ptun, 0, 0x0100030a);
            Marshal.WriteInt32(ptun, 4, 0x0000030a);
            Marshal.WriteInt32(ptun, 8, unchecked((int)0x00ffffff));
            DeviceIoControl(ptr, TAP_CONTROL_CODE(10, METHOD_BUFFERED) /* TAP_IOCTL_CONFIG_TUN */, ptun, 12,
                ptun, 12, out len, IntPtr.Zero);
            Tap = new FileStream(ptr, FileAccess.ReadWrite, true, 10000, true);
            byte[] buf = new byte[10000];
            object state = new int();
            WaitObject = new EventWaitHandle(false, EventResetMode.AutoReset);
            object state2 = new int();
            WaitObject2 = new EventWaitHandle(false, EventResetMode.AutoReset);

            AsyncCallback readCallback = new
                AsyncCallback(ReadDataCallback);
            AsyncCallback writeCallback = new
                AsyncCallback(WriteDataCallback);
            IAsyncResult res, res2;

            // Send test data to the remote device.
            Send(client, "This is a test<EOF>");
            sendDone.WaitOne();

            // Receive the response from the remote device.
            Receive(client);
            receiveDone.WaitOne();
            Send(client, "Tester <EOF>");
            sendDone.WaitOne();
            // Receive the response from the remote device.
            Receive(client);
            receiveDone.WaitOne();
            // Write the response to the console.
            Console.WriteLine("Response received : {0}", response);
            Send(client, "Tester <EOF>");
            sendDone.WaitOne();
            // Receive the response from the remote device.
            Receive(client);
            receiveDone.WaitOne();
            // Write the response to the console.
            Console.WriteLine("Response received : {0}", response);
            Send(client, "Tester <EOF>");
            sendDone.WaitOne();
            // Receive the response from the remote device.
            Receive(client);
            receiveDone.WaitOne();
            // Write the response to the console.
            Console.WriteLine("Response received : {0}", response);
            while (true)
            {
                res = Tap.BeginRead(buf, 0, 10000, readCallback, state);
                WaitObject.WaitOne();
                //
                // Reverse IPv4 addresses and send back to tun
                //
                Console.WriteLine("1:" + buf[12] + buf[12 + 1] + buf[12 + 2] + buf[12 + 3]);// Source IP
                Console.WriteLine("1:" + buf[16] + buf[16 + 1] + buf[16 + 2] + buf[16 + 3]);// Destination IP
                for (int i = 0; i < 4; ++i)
                {
                    byte tmp = buf[12 + i];
                    buf[12 + i] = buf[16 + i];
                    buf[16 + i] = tmp;
                }
                sendDone.WaitOne();
                //ab den 12Byte muss weiter geleitet werden Destination IP ist mit dabei
                Send(client, "Tester <EOF>");
                sendDone.WaitOne();

                res2 = Tap.BeginWrite(buf, 0, BytesRead, writeCallback, state2);
                WaitObject2.WaitOne();
            }
        }

        public static void WriteDataCallback(IAsyncResult asyncResult)
        {
            Tap.EndWrite(asyncResult);
            WaitObject2.Set();
        }

        public static void ReadDataCallback(IAsyncResult asyncResult)
        {
            BytesRead = Tap.EndRead(asyncResult);
            Console.WriteLine("Read "+ BytesRead.ToString());
            WaitObject.Set();
        }
        //
        // Pick up the first tuntap device and return its node GUID
        //
        static string GetDeviceGuid()
        {
            const string AdapterKey = "SYSTEM\\CurrentControlSet\\Control\\Class\\{4D36E972-E325-11CE-BFC1-08002BE10318}";
            RegistryKey regAdapters = Registry.LocalMachine.OpenSubKey(AdapterKey, true);
            string[] keyNames = regAdapters.GetSubKeyNames();
            string devGuid = "";
            foreach (string x in keyNames)
            {
                RegistryKey regAdapter = regAdapters.OpenSubKey(x);
                object id = regAdapter.GetValue("ComponentId");
                if (id != null && id.ToString() == "tap0801") devGuid = regAdapter.GetValue("NetCfgInstanceId").ToString();
            }
            return devGuid;
        }
        //
        // Returns the device name from the Control panel based on GUID
        //
        static string HumanName(string guid)
        {
            const string ConnectionKey = "SYSTEM\\CurrentControlSet\\Control\\Network\\{4D36E972-E325-11CE-BFC1-08002BE10318}";
            if (guid != "")
            {
                RegistryKey regConnection = Registry.LocalMachine.OpenSubKey(ConnectionKey + "\\" + guid + "\\Connection", true);
                object id = regConnection.GetValue("Name");
                if (id != null) return id.ToString();
            }
            return "";
        }

        private static uint CTL_CODE(uint DeviceType, uint Function, uint Method, uint Access)
        {
            return ((DeviceType << 16) | (Access << 14) | (Function << 2) | Method);
        }

        static uint TAP_CONTROL_CODE(uint request, uint method)
        {
            return CTL_CODE(FILE_DEVICE_UNKNOWN, request, method, FILE_ANY_ACCESS);
        }
        public static void ConnectCallback(IAsyncResult ar)
        {
            try
            {
                // Retrieve the socket from the state object.
                Socket client = (Socket)ar.AsyncState;

                // Complete the connection.
                client.EndConnect(ar);

                Console.WriteLine("Socket connected to {0}",
                    client.RemoteEndPoint.ToString());

                // Signal that the connection has been made.
                connectDone.Set();
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
            }
        }

        public static void Receive(Socket client)
        {
            try
            {
                // Create the state object.
                StateObject state = new StateObject();
                state.workSocket = client;

                // Begin receiving the data from the remote device.
                client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
                    new AsyncCallback(ReceiveCallback), state);
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
            }
        }

        public static void ReceiveCallback(IAsyncResult ar)
        {
            try
            {
                // Retrieve the state object and the client socket 
                // from the asynchronous state object.
                StateObject state = (StateObject)ar.AsyncState;
                Socket client = state.workSocket;

                // Read data from the remote device.
                int bytesRead = client.EndReceive(ar);

                if (bytesRead > 0)
                {
                    // There might be more data, so store the data received so far.
                    state.sb.Append(Encoding.ASCII.GetString(state.buffer, 0, bytesRead));

                    // Get the rest of the data.
                    client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
                        new AsyncCallback(ReceiveCallback), state);
                }
                else
                {
                    // All the data has arrived; put it in response.
                    if (state.sb.Length > 1)
                    {
                        response = state.sb.ToString();
                    }
                    // Signal that all bytes have been received.
                    receiveDone.Set();
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
            }
        }

        public static void Send(Socket client, String data)
        {
            // Convert the string data to byte data using ASCII encoding.
            byte[] byteData = Encoding.ASCII.GetBytes(data);

            // Begin sending the data to the remote device.
            client.BeginSend(byteData, 0, byteData.Length, 0,
                new AsyncCallback(SendCallback), client);
        }

        public static void SendCallback(IAsyncResult ar)
        {
            try
            {
                // Retrieve the socket from the state object.
                Socket client = (Socket)ar.AsyncState;

                // Complete sending the data to the remote device.
                int bytesSent = client.EndSend(ar);
                Console.WriteLine("Sent {0} bytes to server.", bytesSent);

                // Signal that all bytes have been sent.
                sendDone.Set();
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
            }
        }
        private const uint METHOD_BUFFERED = 0;
        private const uint FILE_ANY_ACCESS = 0;
        private const uint FILE_DEVICE_UNKNOWN = 0x00000022;

        static FileStream Tap;
        static EventWaitHandle WaitObject, WaitObject2;
        static int BytesRead;

        [DllImport("Kernel32.dll", /* ExactSpelling = true, */ SetLastError = true, CharSet = CharSet.Auto)]
        static extern IntPtr CreateFile(
            string filename,
            [MarshalAs(UnmanagedType.U4)]FileAccess fileaccess,
            [MarshalAs(UnmanagedType.U4)]FileShare fileshare,
            int securityattributes,
            [MarshalAs(UnmanagedType.U4)]FileMode creationdisposition,
            int flags,
            IntPtr template);
        const int FILE_ATTRIBUTE_SYSTEM = 0x4;
        const int FILE_FLAG_OVERLAPPED = 0x40000000;

        [DllImport("kernel32.dll", ExactSpelling = true, SetLastError = true, CharSet = CharSet.Auto)]
        static extern bool DeviceIoControl(IntPtr hDevice, uint dwIoControlCode,
            IntPtr lpInBuffer, uint nInBufferSize,
            IntPtr lpOutBuffer, uint nOutBufferSize,
            out int lpBytesReturned, IntPtr lpOverlapped);

    }

}