HttpTunnel

/// <summary>
    /// Summary description for httptunnel.
    /// </summary>
    public class HttpTunnel
    {
        private IPHostEntry proxyEntry;
        private IPAddress proxyIp;
        private IPEndPoint proxyEndPoint;
        private Socket sock;

        public IPHostEntry ProxyEntry
        {
            get { return proxyEntry; }
        }
        public IPAddress ProxyIp
        {
            get { return proxyIp; }
        }
        public IPEndPoint ProxyEndPoint
        {
            get { return proxyEndPoint; }
        }
        public Socket Tunnel
        {
            get { return sock; }
        }

        public bool Create(string proxyIpAddress, int port, string uid, string pwd, string destIp, string destPort)
        {
            proxyEntry = Dns.GetHostEntry(proxyIpAddress);
            proxyIp = proxyEntry.AddressList[0];
            proxyEndPoint = new IPEndPoint(proxyIp, port);
            sock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            sock.Connect(proxyEndPoint);
            string EncodedData = EncodeUidAndPwd(uid, pwd);
            string proxymsg = "CONNECT " + destIp + ":" + destPort + " HTTP/1.0\nProxy-Authorization:Basic " + EncodedData + "\n\n";
            byte[] buffer = Encoding.ASCII.GetBytes(proxymsg);
            byte[] buffer12 = new byte[500];
            sock.Send(buffer, buffer.Length, 0);
            int msg = sock.Receive(buffer12, 500, 0);
            string data = Encoding.ASCII.GetString(buffer12);
            int index = data.IndexOf("200");
            return index != -1;
        }

        public string EncodeUidAndPwd(string uid, string pwd)
        {
            string uidpwd = uid + ":" + pwd;
            byte[] data = UnicodeEncoding.UTF8.GetBytes(uidpwd);
            Base64Encoder encoder = new Base64Encoder(data);
            return new string(encoder.GetEncoded());
        }
    }

    /// <summary>
    /// Summary description for Base64Encoder.
    /// </summary>
    internal class Base64Encoder
    {
        byte[] source;
        int length, length2;
        int blockCount;
        int paddingCount;

        public Base64Encoder(byte[] input)
        {
            source = input;
            length = input.Length;
            if ((length % 3) == 0)
            {
                paddingCount = 0;
                blockCount = length / 3;
            }
            else
            {
                paddingCount = 3 - (length % 3);//need to add padding
                blockCount = (length + paddingCount) / 3;
            }
            length2 = length + paddingCount;//or blockCount *3
        }
        public char[] GetEncoded()
        {
            byte[] source2;
            source2 = new byte[length2];
            //copy data over insert padding
            for (int x = 0; x < length2; x++)
            {
                if (x < length)
                {
                    source2[x] = source[x];
                }
                else
                {
                    source2[x] = 0;
                }
            }

            byte b1, b2, b3;
            byte temp, temp1, temp2, temp3, temp4;
            byte[] buffer = new byte[blockCount * 4];
            char[] result = new char[blockCount * 4];
            for (int x = 0; x < blockCount; x++)
            {
                b1 = source2[x * 3];
                b2 = source2[x * 3 + 1];
                b3 = source2[x * 3 + 2];

                temp1 = (byte)((b1 & 252) >> 2);//first

                temp = (byte)((b1 & 3) << 4);
                temp2 = (byte)((b2 & 240) >> 4);
                temp2 += temp; //second

                temp = (byte)((b2 & 15) << 2);
                temp3 = (byte)((b3 & 192) >> 6);
                temp3 += temp; //third

                temp4 = (byte)(b3 & 63); //fourth

                buffer[x * 4] = temp1;
                buffer[x * 4 + 1] = temp2;
                buffer[x * 4 + 2] = temp3;
                buffer[x * 4 + 3] = temp4;

            }

            for (int x = 0; x < blockCount * 4; x++)
            {
                result[x] = sixbit2char(buffer[x]);
            }

            //covert last "A"s to "=", based on paddingCount
            switch (paddingCount)
            {
                case 0:
                    break;
                case 1:
                    result[blockCount * 4 - 1] = '=';
                    break;
                case 2:
                    result[blockCount * 4 - 1] = '=';
                    result[blockCount * 4 - 2] = '=';
                    break;
                default: break;
            }
            return result;
        }

        private char sixbit2char(byte b)
        {
            char[] lookupTable = new char[64]
            {
                'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
                'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z',
                '0','1','2','3','4','5','6','7','8','9','+','/'
            };

            if ((b >= 0) && (b <= 63))
            {
                return lookupTable[(int)b];
            }
            else
            {
                //should not happen;
                return ' ';
            }
        }
    }