dll/win32/winhttp/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 #include <stdio.h>
  20
  21 #ifndef IN6ADDRSZ
  22 #define IN6ADDRSZ       16
  23 #endif
  24
  25 #ifndef INT16SZ
  26 #define INT16SZ         2
  27 #endif
  28
  29 #ifdef SPRINTF_CHAR
  30 # define SPRINTF(x) strlen(sprintf/**/x)
  31 #else
  32 # define SPRINTF(x) ((size_t)sprintf x)
  33 #endif
  34
  35 /*
  36  * WARNING: Don't even consider trying to compile this on a system where
  37  * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
  38  */
  39
  40 static const char *inet_ntop4(const u_char *src, char *dst, size_t size);
  41
  42 #ifdef INET6
  43 static const char *inet_ntop6(const u_char *src, char *dst, size_t size);
  44 #endif
  45
  46 /* char *
  47  * inet_ntop(af, src, dst, size)
  48  *      convert a network format address to presentation format.
  49  * return:
  50  *      pointer to presentation format address (`dst'), or NULL (see errno).
  51  * author:
  52  *      Paul Vixie, 1996.
  53  */
  54 const char *
  55 inet_ntop(int af, const void *src, char *dst, size_t size)
  56 {
  57
  58         switch (af) {
  59         case AF_INET:
  60                 return (inet_ntop4(src, dst, size));
  61 #ifdef INET6
  62         case AF_INET6:
  63                 return (inet_ntop6(src, dst, size));
  64 #endif
  65         default:
  66                 WSASetLastError(WSAEAFNOSUPPORT);
  67                 return (NULL);
  68         }
  69         /* NOTREACHED */
  70 }
  71
  72 /* const char *
  73  * inet_ntop4(src, dst, size)
  74  *      format an IPv4 address, more or less like inet_ntoa()
  75  * return:
  76  *      `dst' (as a const)
  77  * notes:
  78  *      (1) uses no statics
  79  *      (2) takes a u_char* not an in_addr as input
  80  * author:
  81  *      Paul Vixie, 1996.
  82  */
  83 static const char *
  84 inet_ntop4(const u_char *src, char *dst, size_t size)
  85 {
  86         static const char fmt[] = "%u.%u.%u.%u";
  87         char tmp[sizeof "255.255.255.255"];
  88
  89         if (SPRINTF((tmp, fmt, src[0], src[1], src[2], src[3])) > size) {
  90                 WSASetLastError(WSAEINVAL);
  91                 return (NULL);
  92         }
  93         strcpy(dst, tmp);
  94         return (dst);
  95 }
  96
  97 #ifdef INET6
  98 /* const char *
  99  * inet_ntop6(src, dst, size)
 100  *      convert IPv6 binary address into presentation (printable) format
 101  * author:
 102  *      Paul Vixie, 1996.
 103  */
 104 static const char *
 105 inet_ntop6(const u_char *src, char *dst, size_t size)
 106 {
 107         /*
 108          * Note that int32_t and int16_t need only be "at least" large enough
 109          * to contain a value of the specified size.  On some systems, like
 110          * Crays, there is no such thing as an integer variable with 16 bits.
 111          * Keep this in mind if you think this function should have been coded
 112          * to use pointer overlays.  All the world's not a VAX.
 113          */
 114         char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
 115         struct { int base, len; } best, cur;
 116         u_int words[IN6ADDRSZ / INT16SZ];
 117         int i;
 118
 119         /*
 120          * Preprocess:
 121          *      Copy the input (bytewise) array into a wordwise array.
 122          *      Find the longest run of 0x00's in src[] for :: shorthanding.
 123          */
 124         memset(words, '\0', sizeof words);
 125         for (i = 0; i < IN6ADDRSZ; i++)
 126                 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
 127         best.base = -1;
 128         cur.base = -1;
 129         for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
 130                 if (words[i] == 0) {
 131                         if (cur.base == -1)
 132                                 cur.base = i, cur.len = 1;
 133                         else
 134                                 cur.len++;
 135                 } else {
 136                         if (cur.base != -1) {
 137                                 if (best.base == -1 || cur.len > best.len)
 138                                         best = cur;
 139                                 cur.base = -1;
 140                         }
 141                 }
 142         }
 143         if (cur.base != -1) {
 144                 if (best.base == -1 || cur.len > best.len)
 145                         best = cur;
 146         }
 147         if (best.base != -1 && best.len < 2)
 148                 best.base = -1;
 149
 150         /*
 151          * Format the result.
 152          */
 153         tp = tmp;
 154         for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
 155                 /* Are we inside the best run of 0x00's? */
 156                 if (best.base != -1 && i >= best.base &&
 157                     i < (best.base + best.len)) {
 158                         if (i == best.base)
 159                                 *tp++ = ':';
 160                         continue;
 161                 }
 162                 /* Are we following an initial run of 0x00s or any real hex? */
 163                 if (i != 0)
 164                         *tp++ = ':';
 165                 /* Is this address an encapsulated IPv4? */
 166                 if (i == 6 && best.base == 0 &&
 167                     (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
 168                         if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
 169                                 return (NULL);
 170                         tp += strlen(tp);
 171                         break;
 172                 }
 173                 tp += SPRINTF((tp, "%x", words[i]));
 174         }
 175         /* Was it a trailing run of 0x00's? */
 176         if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ))
 177                 *tp++ = ':';
 178         *tp++ = '\0';
 179
 180         /*
 181          * Check for overflow, copy, and we're done.
 182          */
 183         if ((size_t)(tp - tmp) > size) {
 184                 WSASetLastError(WSAEINVAL);
 185                 return (NULL);
 186         }
 187         strcpy(dst, tmp);
 188         return (dst);
 189 }
 190 #endif
 191