mdw@git.distorted.org.uk Git - adns/blob - src/addrfam.c

   1 /*
   2  * addrfam.c
   3  * - address-family specific code
   4  */
   5 /*
   6  *  This file is part of adns, which is
   7  *    Copyright (C) 1997-2000,2003,2006  Ian Jackson
   8  *    Copyright (C) 1999-2000,2003,2006  Tony Finch
   9  *    Copyright (C) 1991 Massachusetts Institute of Technology
  10  *  (See the file INSTALL for full details.)
  11  *
  12  *  This program is free software; you can redistribute it and/or modify
  13  *  it under the terms of the GNU General Public License as published by
  14  *  the Free Software Foundation; either version 2, or (at your option)
  15  *  any later version.
  16  *
  17  *  This program is distributed in the hope that it will be useful,
  18  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  *  GNU General Public License for more details.
  21  *
  22  *  You should have received a copy of the GNU General Public License
  23  *  along with this program; if not, write to the Free Software Foundation,
  24  *  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  25  */
  26
  27 #include <stdlib.h>
  28 #include <errno.h>
  29 #include <limits.h>
  30 #include <unistd.h>
  31
  32 #include <sys/types.h>
  33 #include <netdb.h>
  34 #include <sys/socket.h>
  35 #include <netinet/in.h>
  36 #include <arpa/inet.h>
  37
  38 #include "internal.h"
  39
  40 /*
  41  * IPv4
  42  */
  43
  44 #define SIN(sa) ((struct sockaddr_in *)(sa))
  45
  46 static void *inet_sockaddr_to_inaddr(struct sockaddr *sa)
  47   { return &SIN(sa)->sin_addr; }
  48
  49 static void inet_prefix_mask(int len, union gen_addr *mask)
  50   { mask->v4.s_addr = htonl(!len ? 0 : 0xffffffff << (32 - len)); }
  51
  52 static int inet_guess_len(const union gen_addr *addr)
  53 {
  54   unsigned a = (ntohl(addr->v4.s_addr) >> 24) & 0xff;
  55
  56   if (a < 128) return 8;
  57   else if (a < 192) return 16;
  58   else if (a < 224) return 24;
  59   else return -1;
  60 }
  61
  62 static int inet_matchp(const union gen_addr *addr,
  63                        const union gen_addr *base,
  64                        const union gen_addr *mask)
  65   { return (addr->v4.s_addr & mask->v4.s_addr) == base->v4.s_addr; }
  66
  67 const afinfo adns__inet_afinfo = {
  68   AF_INET, 32, '.',
  69   inet_sockaddr_to_inaddr, inet_prefix_mask, inet_guess_len, inet_matchp
  70 };
  71
  72 /*
  73  * IPv6
  74  */
  75
  76 #define SIN6(sa) ((struct sockaddr_in6 *)(sa))
  77
  78 static void *inet6_sockaddr_to_inaddr(struct sockaddr *sa)
  79   { return &SIN6(sa)->sin6_addr; }
  80
  81 static void inet6_prefix_mask(int len, union gen_addr *mask)
  82 {
  83   int i = len/8, j = len%8;
  84   unsigned char *m = mask->v6.s6_addr;
  85
  86   assert(len < 128);
  87   memset(m, 0xff, i);
  88   if (j) m[i++] = (0xff << (8-j)) & 0xff;
  89   memset(m + i, 0, 16-i);
  90 }
  91
  92 static int inet6_guess_len(const union gen_addr *addr)
  93   { return 64; }
  94
  95 static int inet6_matchp(const union gen_addr *addr,
  96                         const union gen_addr *base,
  97                         const union gen_addr *mask)
  98 {
  99   int i;
 100   const char *a = addr->v6.s6_addr;
 101   const char *b = base->v6.s6_addr;
 102   const char *m = mask->v6.s6_addr;
 103
 104   for (i = 0; i < 16; i++)
 105     if ((a[i] & m[i]) != b[i]) return 0;
 106   return 1;
 107 }
 108
 109 const afinfo adns__inet6_afinfo = {
 110   AF_INET6, 128, ':',
 111   inet6_sockaddr_to_inaddr, inet6_prefix_mask, inet6_guess_len, inet6_matchp
 112 };