contrib/ldns/compat/inet_ntop.c

   1 /* From openssh 4.3p2 compat/inet_ntop.c */
   2 /* Copyright (c) 1996 by Internet Software Consortium.
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
   9  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  10  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  11  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  12  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  13  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  14  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  15  * SOFTWARE.
  16  */
  17
  18 /* OPENBSD ORIGINAL: lib/libc/net/inet_ntop.c */
  19
  20 #include <ldns/config.h>
  21
  22 #ifndef HAVE_INET_NTOP
  23
  24 #include <sys/param.h>
  25 #include <sys/types.h>
  26 #ifdef HAVE_SYS_SOCKET_H
  27 #include <sys/socket.h>
  28 #endif
  29 #ifdef HAVE_NETINET_IN_H
  30 #include <netinet/in.h>
  31 #endif
  32 #include <string.h>
  33 #include <errno.h>
  34 #include <stdio.h>
  35
  36 #ifndef IN6ADDRSZ
  37 #define IN6ADDRSZ   16   /* IPv6 T_AAAA */
  38 #endif
  39
  40 #ifndef INT16SZ
  41 #define INT16SZ     2    /* for systems without 16-bit ints */
  42 #endif
  43
  44 /*
  45  * WARNING: Don't even consider trying to compile this on a system where
  46  * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
  47  */
  48
  49 static const char *inet_ntop4(const u_char *src, char *dst, size_t size);
  50 static const char *inet_ntop6(const u_char *src, char *dst, size_t size);
  51
  52 /* char *
  53  * inet_ntop(af, src, dst, size)
  54  *      convert a network format address to presentation format.
  55  * return:
  56  *      pointer to presentation format address (`dst'), or NULL (see errno).
  57  * author:
  58  *      Paul Vixie, 1996.
  59  */
  60 const char *
  61 inet_ntop(int af, const void *src, char *dst, size_t size)
  62 {
  63         switch (af) {
  64         case AF_INET:
  65                 return (inet_ntop4(src, dst, size));
  66         case AF_INET6:
  67                 return (inet_ntop6(src, dst, size));
  68         default:
  69 #ifdef EAFNOSUPPORT
  70                 errno = EAFNOSUPPORT;
  71 #else
  72                 errno = ENOSYS;
  73 #endif
  74                 return (NULL);
  75         }
  76         /* NOTREACHED */
  77 }
  78
  79 /* const char *
  80  * inet_ntop4(src, dst, size)
  81  *      format an IPv4 address, more or less like inet_ntoa()
  82  * return:
  83  *      `dst' (as a const)
  84  * notes:
  85  *      (1) uses no statics
  86  *      (2) takes a u_char* not an in_addr as input
  87  * author:
  88  *      Paul Vixie, 1996.
  89  */
  90 static const char *
  91 inet_ntop4(const u_char *src, char *dst, size_t size)
  92 {
  93         static const char fmt[] = "%u.%u.%u.%u";
  94         char tmp[sizeof "255.255.255.255"];
  95         int l;
  96
  97         l = snprintf(tmp, size, fmt, src[0], src[1], src[2], src[3]);
  98         if (l <= 0 || l >= (int)size) {
  99                 errno = ENOSPC;
 100                 return (NULL);
 101         }
 102         strlcpy(dst, tmp, size);
 103         return (dst);
 104 }
 105
 106 /* const char *
 107  * inet_ntop6(src, dst, size)
 108  *      convert IPv6 binary address into presentation (printable) format
 109  * author:
 110  *      Paul Vixie, 1996.
 111  */
 112 static const char *
 113 inet_ntop6(const u_char *src, char *dst, size_t size)
 114 {
 115         /*
 116          * Note that int32_t and int16_t need only be "at least" large enough
 117          * to contain a value of the specified size.  On some systems, like
 118          * Crays, there is no such thing as an integer variable with 16 bits.
 119          * Keep this in mind if you think this function should have been coded
 120          * to use pointer overlays.  All the world's not a VAX.
 121          */
 122         char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"];
 123         char *tp, *ep;
 124         struct { int base, len; } best, cur;
 125         u_int words[IN6ADDRSZ / INT16SZ];
 126         int i;
 127         int advance;
 128
 129         /*
 130          * Preprocess:
 131          *      Copy the input (bytewise) array into a wordwise array.
 132          *      Find the longest run of 0x00's in src[] for :: shorthanding.
 133          */
 134         memset(words, '\0', sizeof words);
 135         for (i = 0; i < IN6ADDRSZ; i++)
 136                 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
 137         best.base = -1;
 138         best.len = 0;
 139         cur.base = -1;
 140         cur.len = 0;
 141         for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
 142                 if (words[i] == 0) {
 143                         if (cur.base == -1)
 144                                 cur.base = i, cur.len = 1;
 145                         else
 146                                 cur.len++;
 147                 } else {
 148                         if (cur.base != -1) {
 149                                 if (best.base == -1 || cur.len > best.len)
 150                                         best = cur;
 151                                 cur.base = -1;
 152                         }
 153                 }
 154         }
 155         if (cur.base != -1) {
 156                 if (best.base == -1 || cur.len > best.len)
 157                         best = cur;
 158         }
 159         if (best.base != -1 && best.len < 2)
 160                 best.base = -1;
 161
 162         /*
 163          * Format the result.
 164          */
 165         tp = tmp;
 166         ep = tmp + sizeof(tmp);
 167         for (i = 0; i < (IN6ADDRSZ / INT16SZ) && tp < ep; i++) {
 168                 /* Are we inside the best run of 0x00's? */
 169                 if (best.base != -1 && i >= best.base &&
 170                     i < (best.base + best.len)) {
 171                         if (i == best.base) {
 172                                 if (tp + 1 >= ep)
 173                                         return (NULL);
 174                                 *tp++ = ':';
 175                         }
 176                         continue;
 177                 }
 178                 /* Are we following an initial run of 0x00s or any real hex? */
 179                 if (i != 0) {
 180                         if (tp + 1 >= ep)
 181                                 return (NULL);
 182                         *tp++ = ':';
 183                 }
 184                 /* Is this address an encapsulated IPv4? */
 185                 if (i == 6 && best.base == 0 &&
 186                     (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
 187                         if (!inet_ntop4(src+12, tp, (size_t)(ep - tp)))
 188                                 return (NULL);
 189                         tp += strlen(tp);
 190                         break;
 191                 }
 192                 advance = snprintf(tp, ep - tp, "%x", words[i]);
 193                 if (advance <= 0 || advance >= ep - tp)
 194                         return (NULL);
 195                 tp += advance;
 196         }
 197         /* Was it a trailing run of 0x00's? */
 198         if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) {
 199                 if (tp + 1 >= ep)
 200                         return (NULL);
 201                 *tp++ = ':';
 202         }
 203         if (tp + 1 >= ep)
 204                 return (NULL);
 205         *tp++ = '\0';
 206
 207         /*
 208          * Check for overflow, copy, and we're done.
 209          */
 210         if ((size_t)(tp - tmp) > size) {
 211                 errno = ENOSPC;
 212                 return (NULL);
 213         }
 214         strlcpy(dst, tmp, size);
 215         return (dst);
 216 }
 217
 218 #endif /* !HAVE_INET_NTOP */