Line data    Source code

       1             : // Snap Websites Server -- inet helper functions
       2             : // Copyright (c) 2011-2019  Made to Order Software Corp.  All Rights Reserved
       3             : //
       4             : // This program is free software; you can redistribute it and/or modify
       5             : // it under the terms of the GNU General Public License as published by
       6             : // the Free Software Foundation; either version 2 of the License, or
       7             : // (at your option) any later version.
       8             : //
       9             : // This program is distributed in the hope that it will be useful,
      10             : // but WITHOUT ANY WARRANTY; without even the implied warranty of
      11             : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      12             : // GNU General Public License for more details.
      13             : //
      14             : // You should have received a copy of the GNU General Public License
      15             : // along with this program; if not, write to the Free Software
      16             : // Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
      17             : 
      18             : 
      19             : // self
      20             : //
      21             : #include "snapwebsites/inet_helpers.h"
      22             : 
      23             : 
      24             : // C++ lib
      25             : //
      26             : #include <iostream>
      27             : 
      28             : 
      29             : // last include
      30             : //
      31             : #include <snapdev/poison.h>
      32             : 
      33             : 
      34             : 
      35             : namespace snap
      36             : {
      37             : namespace snap_inet
      38             : {
      39             : 
      40             : 
      41             : 
      42             : 
      43             : /** \brief Convert a string to a in6_addr structure.
      44             :  *
      45             :  * This function is similar to inet_pton() only it always converts
      46             :  * the address to an IPv6 address. The input may be an IPv4 address
      47             :  * or an IPv6 address.
      48             :  *
      49             :  * If the input is neither an IPv4 nor an IPv6 address, the function
      50             :  * returns 0 and sets errno to EAFNOSUPPORT.
      51             :  *
      52             :  * \note
      53             :  * The function clears the IP address in dst if an error occurs.
      54             :  * In other words you end up with "IN6ADDR_ANY".
      55             :  *
      56             :  * \note
      57             :  * An IPv4 in an IPv6 address is just preceded by "::ffff:". So
      58             :  * in most cases you do not need such.
      59             :  *
      60             :  * \warning
      61             :  * IPv4 embedded in an IPv6 address should not be used over the wire.
      62             :  * In most cases this function is used to save IP address in binary
      63             :  * in one format rather than having to know which format the address
      64             :  * was being saved as (i.e. the row or column key of some data in
      65             :  * Cassandra.)
      66             :  *
      67             :  * \param[in] src  The string representing an IP address.
      68             :  * \param[out] dst  A pointer to a in6_addr buffer.
      69             :  *
      70             :  * \return 0 on error and errno set to EAFNOSUPPORT, otherwise 1
      71             :  *         and dst set to a valid IPv6 address.
      72             :  */
      73           0 : int inet_pton_v6(char const * src, struct in6_addr * dst)
      74             : {
      75           0 :     int const r6(inet_pton(AF_INET6, src, dst));
      76           0 :     if(r6 != 1)
      77             :     {
      78             :         // try again with IPv4
      79             :         struct in_addr addr;
      80           0 :         int const r4(inet_pton(AF_INET, src, &addr));
      81           0 :         if(r4 != 1)
      82             :         {
      83             :             // reset the address, it is not good
      84           0 :             for(size_t i(0); i < sizeof(in6_addr); ++i)
      85             :             {
      86           0 :                 reinterpret_cast<char *>(dst)[i] = 0;
      87             :             }
      88           0 :             return 0;
      89             :         }
      90             : 
      91             :         // convert an IPv4 to an IPv6... (i.e. embedding)
      92           0 :         std::string ipv6("::ffff:");
      93           0 :         ipv6 += src;
      94           0 :         int const r46(inet_pton(AF_INET6, ipv6.c_str(), dst));
      95           0 :         if(r46 != 1)
      96             :         {
      97             :             // somehow it worked as IPv4, but not IPv6?!?
      98           0 :             for(size_t i(0); i < sizeof(in6_addr); ++i)
      99             :             {
     100           0 :                 reinterpret_cast<char *>(dst)[i] = 0;
     101             :             }
     102           0 :             errno = EAFNOSUPPORT;
     103           0 :             return 0;
     104             :         }
     105             :     }
     106             : 
     107             :     // it work, user has result in 'dst'
     108           0 :     return 1;
     109             : }
     110             : 
     111             : 
     112             : } // snap_inet namespace
     113           6 : } // snap namespace
     114             : // vim: ts=4 sw=4 et