reactos/dll/win32/wininet/inet_ntop.c

   1 /* from NetBSD: inet_ntop.c,v 1.9 2000/01/22 22:19:16 mycroft Exp */
   2
   3 /* Copyright (c) 1996 by Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
  10  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  11  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  12  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  13  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  14  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  15  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  16  * SOFTWARE.
  17  */
  18
  19 #define ENOSPC 28
  20 #define EAFNOSUPPORT 52
  21
  22 #ifndef IN6ADDRSZ
  23 #define IN6ADDRSZ       16
  24 #endif
  25
  26 #ifndef INT16SZ
  27 #define INT16SZ         2
  28 #endif
  29
  30 #ifdef SPRINTF_CHAR
  31 # define SPRINTF(x) strlen(sprintf/**/x)
  32 #else
  33 # define SPRINTF(x) ((size_t)sprintf x)
  34 #endif
  35
  36 /*
  37  * WARNING: Don't even consider trying to compile this on a system where
  38  * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
  39  */
  40
  41 static const char *inet_ntop4(const u_char *src, char *dst, size_t size);
  42
  43 #ifdef INET6
  44 static const char *inet_ntop6(const u_char *src, char *dst, size_t size);
  45 #endif
  46
  47 /* char *
  48  * inet_ntop(af, src, dst, size)
  49  *      convert a network format address to presentation format.
  50  * return:
  51  *      pointer to presentation format address (`dst'), or NULL (see errno).
  52  * author:
  53  *      Paul Vixie, 1996.
  54  */
  55 const char *
  56 inet_ntop(int af, const void *src, char *dst, size_t size)
  57 {
  58
  59         switch (af) {
  60         case AF_INET:
  61                 return (inet_ntop4(src, dst, size));
  62 #ifdef INET6
  63         case AF_INET6:
  64                 return (inet_ntop6(src, dst, size));
  65 #endif
  66         default:
  67                 errno = EAFNOSUPPORT;
  68                 return (NULL);
  69         }
  70         /* NOTREACHED */
  71 }
  72
  73 /* const char *
  74  * inet_ntop4(src, dst, size)
  75  *      format an IPv4 address, more or less like inet_ntoa()
  76  * return:
  77  *      `dst' (as a const)
  78  * notes:
  79  *      (1) uses no statics
  80  *      (2) takes a u_char* not an in_addr as input
  81  * author:
  82  *      Paul Vixie, 1996.
  83  */
  84 static const char *
  85 inet_ntop4(const u_char *src, char *dst, size_t size)
  86 {
  87         static const char fmt[] = "%u.%u.%u.%u";
  88         char tmp[sizeof "255.255.255.255"];
  89
  90         if (SPRINTF((tmp, fmt, src[0], src[1], src[2], src[3])) > size) {
  91                 errno = ENOSPC;
  92                 return (NULL);
  93         }
  94         strcpy(dst, tmp);
  95         return (dst);
  96 }
  97
  98 #ifdef INET6
  99 /* const char *
 100  * inet_ntop6(src, dst, size)
 101  *      convert IPv6 binary address into presentation (printable) format
 102  * author:
 103  *      Paul Vixie, 1996.
 104  */
 105 static const char *
 106 inet_ntop6(const u_char *src, char *dst, size_t size)
 107 {
 108         /*
 109          * Note that int32_t and int16_t need only be "at least" large enough
 110          * to contain a value of the specified size.  On some systems, like
 111          * Crays, there is no such thing as an integer variable with 16 bits.
 112          * Keep this in mind if you think this function should have been coded
 113          * to use pointer overlays.  All the world's not a VAX.
 114          */
 115         char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
 116         struct { int base, len; } best, cur;
 117         u_int words[IN6ADDRSZ / INT16SZ];
 118         int i;
 119
 120         /*
 121          * Preprocess:
 122          *      Copy the input (bytewise) array into a wordwise array.
 123          *      Find the longest run of 0x00's in src[] for :: shorthanding.
 124          */
 125         memset(words, '\0', sizeof words);
 126         for (i = 0; i < IN6ADDRSZ; i++)
 127                 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
 128         best.base = -1;
 129         cur.base = -1;
 130         for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
 131                 if (words[i] == 0) {
 132                         if (cur.base == -1)
 133                                 cur.base = i, cur.len = 1;
 134                         else
 135                                 cur.len++;
 136                 } else {
 137                         if (cur.base != -1) {
 138                                 if (best.base == -1 || cur.len > best.len)
 139                                         best = cur;
 140                                 cur.base = -1;
 141                         }
 142                 }
 143         }
 144         if (cur.base != -1) {
 145                 if (best.base == -1 || cur.len > best.len)
 146                         best = cur;
 147         }
 148         if (best.base != -1 && best.len < 2)
 149                 best.base = -1;
 150
 151         /*
 152          * Format the result.
 153          */
 154         tp = tmp;
 155         for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
 156                 /* Are we inside the best run of 0x00's? */
 157                 if (best.base != -1 && i >= best.base &&
 158                     i < (best.base + best.len)) {
 159                         if (i == best.base)
 160                                 *tp++ = ':';
 161                         continue;
 162                 }
 163                 /* Are we following an initial run of 0x00s or any real hex? */
 164                 if (i != 0)
 165                         *tp++ = ':';
 166                 /* Is this address an encapsulated IPv4? */
 167                 if (i == 6 && best.base == 0 &&
 168                     (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
 169                         if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
 170                                 return (NULL);
 171                         tp += strlen(tp);
 172                         break;
 173                 }
 174                 tp += SPRINTF((tp, "%x", words[i]));
 175         }
 176         /* Was it a trailing run of 0x00's? */
 177         if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ))
 178                 *tp++ = ':';
 179         *tp++ = '\0';
 180
 181         /*
 182          * Check for overflow, copy, and we're done.
 183          */
 184         if ((size_t)(tp - tmp) > size) {
 185                 errno = ENOSPC;
 186                 return (NULL);
 187         }
 188         strcpy(dst, tmp);
 189         return (dst);
 190 }
 191 #endif
 192