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 static int inet_rev_parsecomp(const char *p, size_t n)
  68 {
  69   int i = 0;
  70   if (n > 3) return -1;
  71
  72   while (n--) {
  73     if ('0' <= *p && *p <= '9') i = 10*i + *p++ - '0';
  74     else return -1;
  75   }
  76   return i;
  77 }
  78
  79 static void inet_rev_mkaddr(union gen_addr *addr, const byte *ipv)
  80 {
  81   addr->v4.s_addr = htonl((ipv[3]<<24) | (ipv[2]<<16) |
  82                           (ipv[1]<<8) | (ipv[0]));
  83 }
  84
  85 static char *inet_rev_mkname(struct sockaddr *sa, char *buf)
  86 {
  87   unsigned long a = ntohl(SIN(sa)->sin_addr.s_addr);
  88   int i;
  89
  90   for (i = 0; i < 4; i++) {
  91     if (i) *buf++ = '.';
  92     buf += sprintf(buf, "%d", (int)(a & 0xff));
  93     a >>= 8;
  94   }
  95   return buf;
  96 }
  97
  98 const afinfo adns__inet_afinfo = {
  99   AF_INET, 32, '.', 4, 3, adns_r_a,
 100   inet_sockaddr_to_inaddr, inet_prefix_mask, inet_guess_len, inet_matchp,
 101   inet_rev_parsecomp, inet_rev_mkaddr, inet_rev_mkname
 102 };
 103
 104 /*
 105  * IPv6
 106  */
 107
 108 #define SIN6(sa) ((struct sockaddr_in6 *)(sa))
 109
 110 static void *inet6_sockaddr_to_inaddr(struct sockaddr *sa)
 111   { return &SIN6(sa)->sin6_addr; }
 112
 113 static void inet6_prefix_mask(int len, union gen_addr *mask)
 114 {
 115   int i = len/8, j = len%8;
 116   unsigned char *m = mask->v6.s6_addr;
 117
 118   assert(len < 128);
 119   memset(m, 0xff, i);
 120   if (j) m[i++] = (0xff << (8-j)) & 0xff;
 121   memset(m + i, 0, 16-i);
 122 }
 123
 124 static int inet6_guess_len(const union gen_addr *addr)
 125   { return 64; }
 126
 127 static int inet6_matchp(const union gen_addr *addr,
 128                         const union gen_addr *base,
 129                         const union gen_addr *mask)
 130 {
 131   int i;
 132   const char *a = addr->v6.s6_addr;
 133   const char *b = base->v6.s6_addr;
 134   const char *m = mask->v6.s6_addr;
 135
 136   for (i = 0; i < 16; i++)
 137     if ((a[i] & m[i]) != b[i]) return 0;
 138   return 1;
 139 }
 140
 141 static int inet6_rev_parsecomp(const char *p, size_t n)
 142 {
 143   if (n != 1) return -1;
 144   else if ('0' <= *p && *p <= '9') return *p - '0';
 145   else if ('a' <= *p && *p <= 'f') return *p - 'a' + 10;
 146   else if ('A' <= *p && *p <= 'F') return *p - 'a' + 10;
 147   else return -1;
 148 }
 149
 150 static void inet6_rev_mkaddr(union gen_addr *addr, const byte *ipv)
 151 {
 152   unsigned char *a = addr->v6.s6_addr;
 153   int i;
 154
 155   for (i = 0; i < 16; i++)
 156     a[i] = (ipv[31-2*i] << 4) | (ipv[30-2*i] << 0);
 157 }
 158
 159 static char *inet6_rev_mkname(struct sockaddr *sa, char *buf)
 160 {
 161   unsigned char *a = SIN6(sa)->sin6_addr.s6_addr + 16;
 162   unsigned c, y;
 163   int i, j;
 164
 165   for (i = 0; i < 16; i++) {
 166     c = *--a;
 167     for (j = 0; j < 2; j++) {
 168       if (i || j) *buf++ = '.';
 169       y = c & 0xf;
 170       if (y < 10) *buf++ = y + '0';
 171       else *buf++ = y - 10 + 'a';
 172       c >>= 4;
 173     }
 174   }
 175   return buf;
 176 }
 177
 178 const afinfo adns__inet6_afinfo = {
 179   AF_INET6, 128, ':', 32, 1, adns_r_aaaa,
 180   inet6_sockaddr_to_inaddr, inet6_prefix_mask, inet6_guess_len, inet6_matchp,
 181   inet6_rev_parsecomp, inet6_rev_mkaddr, inet6_rev_mkname
 182 };