// IPfilter.cs
// Copyright (C) 2002 Matt Zyzik (www.FileScope.com)
// 
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
// 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

using System.Diagnostics;

namespace FileScope
{
    /// <summary>
    /// Used as a scheme to prevent connecting to private IPs.
    /// </summary>
    public class IPfilter
    {
        /// <summary>
        /// Returns true if the ip is a private local ip.
        /// </summary>
        public static bool Private(string ip)
        {
            if (ip.IndexOf(Stats.settings.ipAddress) != -1)
                return true;
            if (ip.ToLower().IndexOf("localhost") != -1)
                return true;

            //take out the colon and port
            if (ip.IndexOf(":") != -1)
                ip = ip.Substring(0, ip.IndexOf(":"));

            try
            {
                byte[] bytesIP = Endian.BigEndianIP(ip);
                if (bytesIP[0] == 10)
                    return true;
                else if (bytesIP[0] == 172 && bytesIP[1] >= 16 && bytesIP[1] <= 31)
                    return true;
                else if (bytesIP[0] == 192 && bytesIP[1] == 168)
                    return true;
                else if (bytesIP[0] == 127 && bytesIP[1] == 0)
                    return true;
                else if (bytesIP[0] == 0 && bytesIP[1] == 0 && bytesIP[2] == 0 && bytesIP[3] == 0)
                    return true;
                else
                    return false;
            }
            catch
            {
                //probably a host name instead of an ip address
                Debug.WriteLine("IPfilter Private ip: " + ip);
                return false;
            }
        }

        /// <summary>
        /// Returns true if the ip is a private local ip.
        /// However, unlike Private, Private2 will disregard the local public ip address.
        /// </summary>
        public static bool Private2(string ip)
        {
            //take out the colon and port
            if (ip.IndexOf(":") != -1)
                ip = ip.Substring(0, ip.IndexOf(":"));

            try
            {
                byte[] bytesIP = Endian.BigEndianIP(ip);
                if (bytesIP[0] == 10)
                    return true;
                else if (bytesIP[0] == 172 && bytesIP[1] >= 16 && bytesIP[1] <= 31)
                    return true;
                else if (bytesIP[0] == 192 && bytesIP[1] == 168)
                    return true;
                else if (bytesIP[0] == 127 && bytesIP[1] == 0)
                    return true;
                else if (bytesIP[0] == 0 && bytesIP[1] == 0 && bytesIP[2] == 0 && bytesIP[3] == 0)
                    return true;
                else
                    return false;
            }
            catch
            {
                //probably a host name instead of an ip address
                Debug.WriteLine("IPfilter Private ip: " + ip);
                return false;
            }
        }
    }
}