ceph/src/c-ares/inet_ntop.c

   1 /*
   2  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (c) 1996-1999 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 ISC DISCLAIMS ALL WARRANTIES
  10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  15  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 #include "ares_setup.h"
  19
  20 #ifdef HAVE_NETINET_IN_H
  21 #  include <netinet/in.h>
  22 #endif
  23 #ifdef HAVE_ARPA_INET_H
  24 #  include <arpa/inet.h>
  25 #endif
  26 #ifdef HAVE_ARPA_NAMESER_H
  27 #  include <arpa/nameser.h>
  28 #else
  29 #  include "nameser.h"
  30 #endif
  31 #ifdef HAVE_ARPA_NAMESER_COMPAT_H
  32 #  include <arpa/nameser_compat.h>
  33 #endif
  34
  35 #include "ares.h"
  36 #include "ares_ipv6.h"
  37
  38 #ifndef HAVE_INET_NTOP
  39
  40 /*
  41  * WARNING: Don't even consider trying to compile this on a system where
  42  * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
  43  */
  44
  45 static const char *inet_ntop4(const unsigned char *src, char *dst, size_t size);
  46 static const char *inet_ntop6(const unsigned char *src, char *dst, size_t size);
  47
  48 /* char *
  49  * inet_ntop(af, src, dst, size)
  50  *     convert a network format address to presentation format.
  51  * return:
  52  *     pointer to presentation format address (`dst'), or NULL (see errno).
  53  * note:
  54  *     On Windows we store the error in the thread errno, not
  55  *     in the winsock error code. This is to avoid loosing the
  56  *     actual last winsock error. So use macro ERRNO to fetch the
  57  *     errno this funtion sets when returning NULL, not SOCKERRNO.
  58  * author:
  59  *     Paul Vixie, 1996.
  60  */
  61 const char *
  62 ares_inet_ntop(int af, const void *src, char *dst, ares_socklen_t size)
  63 {
  64   switch (af) {
  65   case AF_INET:
  66     return (inet_ntop4(src, dst, (size_t)size));
  67   case AF_INET6:
  68     return (inet_ntop6(src, dst, (size_t)size));
  69   default:
  70     SET_ERRNO(EAFNOSUPPORT);
  71     return (NULL);
  72   }
  73   /* NOTREACHED */
  74 }
  75
  76 /* const char *
  77  * inet_ntop4(src, dst, size)
  78  *     format an IPv4 address
  79  * return:
  80  *     `dst' (as a const)
  81  * notes:
  82  *     (1) uses no statics
  83  *     (2) takes a unsigned char* not an in_addr as input
  84  * author:
  85  *     Paul Vixie, 1996.
  86  */
  87 static const char *
  88 inet_ntop4(const unsigned char *src, char *dst, size_t size)
  89 {
  90   static const char fmt[] = "%u.%u.%u.%u";
  91   char tmp[sizeof("255.255.255.255")];
  92
  93   if ((size_t)sprintf(tmp, fmt, src[0], src[1], src[2], src[3]) >= size) {
  94     SET_ERRNO(ENOSPC);
  95     return (NULL);
  96   }
  97   strcpy(dst, tmp);
  98   return (dst);
  99 }
 100
 101 /* const char *
 102  * inet_ntop6(src, dst, size)
 103  *     convert IPv6 binary address into presentation (printable) format
 104  * author:
 105  *     Paul Vixie, 1996.
 106  */
 107 static const char *
 108 inet_ntop6(const unsigned char *src, char *dst, size_t size)
 109 {
 110   /*
 111    * Note that int32_t and int16_t need only be "at least" large enough
 112    * to contain a value of the specified size.  On some systems, like
 113    * Crays, there is no such thing as an integer variable with 16 bits.
 114    * Keep this in mind if you think this function should have been coded
 115    * to use pointer overlays.  All the world's not a VAX.
 116    */
 117   char tmp[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")];
 118   char *tp;
 119   struct { int base, len; } best, cur;
 120   unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
 121   int i;
 122
 123   /*
 124    * Preprocess:
 125    *  Copy the input (bytewise) array into a wordwise array.
 126    *  Find the longest run of 0x00's in src[] for :: shorthanding.
 127    */
 128   memset(words, '\0', sizeof(words));
 129   for (i = 0; i < NS_IN6ADDRSZ; i++)
 130     words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
 131   best.base = -1;
 132   best.len = 0;
 133   cur.base = -1;
 134   cur.len = 0;
 135   for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 136     if (words[i] == 0) {
 137       if (cur.base == -1)
 138         cur.base = i, cur.len = 1;
 139       else
 140         cur.len++;
 141     } else {
 142       if (cur.base != -1) {
 143         if (best.base == -1 || cur.len > best.len)
 144           best = cur;
 145         cur.base = -1;
 146       }
 147     }
 148   }
 149   if (cur.base != -1) {
 150     if (best.base == -1 || cur.len > best.len)
 151       best = cur;
 152   }
 153   if (best.base != -1 && best.len < 2)
 154     best.base = -1;
 155
 156   /*
 157    * Format the result.
 158    */
 159   tp = tmp;
 160   for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 161     /* Are we inside the best run of 0x00's? */
 162     if (best.base != -1 && i >= best.base &&
 163         i < (best.base + best.len)) {
 164       if (i == best.base)
 165         *tp++ = ':';
 166       continue;
 167     }
 168     /* Are we following an initial run of 0x00s or any real hex? */
 169     if (i != 0)
 170       *tp++ = ':';
 171     /* Is this address an encapsulated IPv4? */
 172     if (i == 6 && best.base == 0 && (best.len == 6 ||
 173         (best.len == 7 && words[7] != 0x0001) ||
 174         (best.len == 5 && words[5] == 0xffff))) {
 175       if (!inet_ntop4(src+12, tp, sizeof(tmp) - (tp - tmp)))
 176         return (NULL);
 177       tp += strlen(tp);
 178       break;
 179     }
 180     tp += sprintf(tp, "%x", words[i]);
 181   }
 182   /* Was it a trailing run of 0x00's? */
 183   if (best.base != -1 && (best.base + best.len) ==
 184       (NS_IN6ADDRSZ / NS_INT16SZ))
 185     *tp++ = ':';
 186   *tp++ = '\0';
 187
 188   /*
 189    * Check for overflow, copy, and we're done.
 190    */
 191   if ((size_t)(tp - tmp) > size) {
 192     SET_ERRNO(ENOSPC);
 193     return (NULL);
 194   }
 195   strcpy(dst, tmp);
 196   return (dst);
 197 }
 198
 199 #else /* HAVE_INET_NTOP */
 200
 201 const char *
 202 ares_inet_ntop(int af, const void *src, char *dst, ares_socklen_t size)
 203 {
 204   /* just relay this to the underlying function */
 205   return inet_ntop(af, src, dst, size);
 206 }
 207
 208 #endif /* HAVE_INET_NTOP */