1                 : /*
       2                 :  * v4global.c - Check whether an IPv4 address is global
       3                 :  * $Id: v4global.c 1726 2006-08-27 08:13:18Z remi $
       4                 :  */
       5                 : 
       6                 : /***********************************************************************
       7                 :  *  Copyright © 2004-2005 Rémi Denis-Courmont.                         *
       8                 :  *  This program is free software; you can redistribute and/or modify  *
       9                 :  *  it under the terms of the GNU General Public License as published  *
      10                 :  *  by the Free Software Foundation; version 2 of the license.         *
      11                 :  *                                                                     *
      12                 :  *  This program is distributed in the hope that it will be useful,    *
      13                 :  *  but WITHOUT ANY WARRANTY; without even the implied warranty of     *
      14                 :  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.               *
      15                 :  *  See the GNU General Public License for more details.               *
      16                 :  *                                                                     *
      17                 :  *  You should have received a copy of the GNU General Public License  *
      18                 :  *  along with this program; if not, you can get it from:              *
      19                 :  *  http://www.gnu.org/copyleft/gpl.html                               *
      20                 :  ***********************************************************************/
      21                 : 
      22                 : #ifdef HAVE_CONFIG_H
      23                 : # include <config.h>
      24                 : #endif
      25                 : 
      26                 : #include <inttypes.h>
      27                 : #include <sys/types.h>
      28                 : #include <netinet/in.h> // ntohl()
      29                 : 
      30                 : #include "v4global.h"
      31                 : 
      32                 : /*
      33                 :  * Checks that ip is a global unicast IPv4 address
      34                 :  * (Values shoud maybe not be hardcoded that way).
      35                 :  */
      36                 : int
      37                 : is_ipv4_global_unicast (uint32_t ip)
      38               0 : {
      39                 :         /*
      40                 :          * NOTE (FIXME)
      41                 :          *
      42                 :          * Additionnaly, the specification forbids broadcast addresses of
      43                 :          * subnets the node is attached to. It would be quite complex to check
      44                 :          * that. We don't set the SO_BROADCAST socket option, which should be
      45                 :          * sufficient to avoid security issues.
      46                 :          */
      47                 : 
      48               0 :         if ((ip & htonl (0x80000000)) == 0)
      49                 :         {
      50                 :                 // Forbidden classes A:
      51                 :                 // 0.0.0.0/8, 10.0.0.0/8 and 127.0.0.0/8
      52               0 :                 ip &= htonl (0xff000000);
      53               0 :                 return ( ip                       != htonl (0x0a000000)) &&
      54                 :                        ( ip                       != htonl (0x7f000000)) &&
      55                 :                        ( ip                       != htonl (0x00000000));
      56                 :         }
      57                 : 
      58               0 :         if ((ip & htonl (0x40000000)) == 0)
      59                 :         {
      60                 :                 // Forbidden classes B:
      61                 :                 // 169.254.0.0/16, 172.16.0.0/12
      62               0 :                 return ((ip & htonl (0xffff0000)) != htonl (0xa9fe0000)) &&
      63                 :                        ((ip & htonl (0xfff00000)) != htonl (0xac100000)); 
      64                 :         }
      65                 : 
      66               0 :         if ((ip & htonl (0x20000000)) == 0)
      67                 :         {
      68                 :                 // Forbidden classes C:
      69                 :                 // 192.168.0.0/16, 192.88.99.0/24
      70               0 :                 return ((ip & htonl (0xffff0000)) != htonl (0xc0a80000)) &&
      71                 :                        ((ip & htonl (0xffffff00)) != htonl (0xc0586200));
      72                 :         }
      73                 : 
      74               0 :         if ((ip & htonl (0x10000000)) == 0)
      75                 :                 // Whole class D space (multicast) is forbidden:
      76               0 :                 return 0;
      77                 : 
      78               0 :         return ip != htonl (0xffffffff);
      79                 : }
      80                 :