src/kits/network/netresolv/inet/inet_cidr_ntop.c

   1 /*      $NetBSD: inet_cidr_ntop.c,v 1.8 2012/03/13 21:13:38 christos Exp $      */
   2
   3 /*
   4  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   5  * Copyright (c) 1998,1999 by Internet Software Consortium.
   6  *
   7  * Permission to use, copy, modify, and distribute this software for any
   8  * purpose with or without fee is hereby granted, provided that the above
   9  * copyright notice and this permission notice appear in all copies.
  10  *
  11  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  13  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  17  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  18  */
  19
  20 #include <sys/cdefs.h>
  21 #if defined(LIBC_SCCS) && !defined(lint)
  22 #if 0
  23 static const char rcsid[] = "Id: inet_cidr_ntop.c,v 1.7 2006/10/11 02:18:18 marka Exp";
  24 #else
  25 __RCSID("$NetBSD: inet_cidr_ntop.c,v 1.8 2012/03/13 21:13:38 christos Exp $");
  26 #endif
  27 #endif
  28
  29 #include "port_before.h"
  30
  31 #include <sys/types.h>
  32 #include <sys/socket.h>
  33 #include <netinet/in.h>
  34 #include <arpa/nameser.h>
  35 #include <arpa/inet.h>
  36
  37 #include <assert.h>
  38 #include <errno.h>
  39 #include <stdio.h>
  40 #include <string.h>
  41 #include <stdlib.h>
  42
  43 #include "port_after.h"
  44
  45 #ifdef __weak_alias
  46 __weak_alias(inet_cidr_ntop,_inet_cidr_ntop)
  47 #endif
  48
  49 #ifdef SPRINTF_CHAR
  50 # define SPRINTF(x) strlen(sprintf/**/x)
  51 #else
  52 # define SPRINTF(x) ((size_t)sprintf x)
  53 #endif
  54
  55 static char *
  56 inet_cidr_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size);
  57 static char *
  58 inet_cidr_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size);
  59
  60 /*%
  61  * char *
  62  * inet_cidr_ntop(af, src, bits, dst, size)
  63  *      convert network address from network to presentation format.
  64  *      "src"'s size is determined from its "af".
  65  * return:
  66  *      pointer to dst, or NULL if an error occurred (check errno).
  67  * note:
  68  *      192.5.5.1/28 has a nonzero host part, which means it isn't a network
  69  *      as called for by inet_net_ntop() but it can be a host address with
  70  *      an included netmask.
  71  * author:
  72  *      Paul Vixie (ISC), October 1998
  73  */
  74 char *
  75 inet_cidr_ntop(int af, const void *src, int bits, char *dst, size_t size) {
  76         switch (af) {
  77         case AF_INET:
  78                 return (inet_cidr_ntop_ipv4(src, bits, dst, size));
  79         case AF_INET6:
  80                 return (inet_cidr_ntop_ipv6(src, bits, dst, size));
  81         default:
  82                 errno = EAFNOSUPPORT;
  83                 return (NULL);
  84         }
  85 }
  86
  87 static int
  88 decoct(const u_char *src, size_t bytes, char *dst, size_t size) {
  89         char *odst = dst;
  90         char *t;
  91         size_t b;
  92
  93         for (b = 1; b <= bytes; b++) {
  94                 if (size < sizeof "255.")
  95                         return (0);
  96                 t = dst;
  97                 dst += SPRINTF((dst, "%u", *src++));
  98                 if (b != bytes) {
  99                         *dst++ = '.';
 100                         *dst = '\0';
 101                 }
 102                 size -= (size_t)(dst - t);
 103         }
 104         assert(INT_MIN <= (dst - odst) && (dst - odst) <= INT_MAX);
 105         return (int)(dst - odst);
 106 }
 107
 108 /*%
 109  * static char *
 110  * inet_cidr_ntop_ipv4(src, bits, dst, size)
 111  *      convert IPv4 network address from network to presentation format.
 112  *      "src"'s size is determined from its "af".
 113  * return:
 114  *      pointer to dst, or NULL if an error occurred (check errno).
 115  * note:
 116  *      network byte order assumed.  this means 192.5.5.240/28 has
 117  *      0b11110000 in its fourth octet.
 118  * author:
 119  *      Paul Vixie (ISC), October 1998
 120  */
 121 static char *
 122 inet_cidr_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size) {
 123         char *odst = dst;
 124         size_t len = 4;
 125         size_t b;
 126         size_t bytes;
 127
 128         if ((bits < -1) || (bits > 32)) {
 129                 errno = EINVAL;
 130                 return (NULL);
 131         }
 132
 133         /* Find number of significant bytes in address. */
 134         if (bits == -1)
 135                 len = 4;
 136         else
 137                 for (len = 1, b = 1 ; b < 4U; b++)
 138                         if (*(src + b))
 139                                 len = b + 1;
 140
 141         /* Format whole octets plus nonzero trailing octets. */
 142         bytes = (((bits <= 0) ? 1 : bits) + 7) / 8;
 143         if (len > bytes)
 144                 bytes = len;
 145         b = decoct(src, bytes, dst, size);
 146         if (b == 0U)
 147                 goto emsgsize;
 148         dst += b;
 149         size -= b;
 150
 151         if (bits != -1) {
 152                 /* Format CIDR /width. */
 153                 if (size < sizeof "/32")
 154                         goto emsgsize;
 155                 dst += SPRINTF((dst, "/%u", bits));
 156         }
 157
 158         return (odst);
 159
 160  emsgsize:
 161         errno = EMSGSIZE;
 162         return (NULL);
 163 }
 164
 165 static char *
 166 inet_cidr_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size) {
 167         /*
 168          * Note that int32_t and int16_t need only be "at least" large enough
 169          * to contain a value of the specified size.  On some systems, like
 170          * Crays, there is no such thing as an integer variable with 16 bits.
 171          * Keep this in mind if you think this function should have been coded
 172          * to use pointer overlays.  All the world's not a VAX.
 173          */
 174         char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255/128"];
 175         char *tp;
 176         struct { int base, len; } best, cur;
 177         u_int words[NS_IN6ADDRSZ / NS_INT16SZ];
 178         int i;
 179
 180         if ((bits < -1) || (bits > 128)) {
 181                 errno = EINVAL;
 182                 return (NULL);
 183         }
 184
 185         /*
 186          * Preprocess:
 187          *      Copy the input (bytewise) array into a wordwise array.
 188          *      Find the longest run of 0x00's in src[] for :: shorthanding.
 189          */
 190         memset(words, '\0', sizeof words);
 191         for (i = 0; i < NS_IN6ADDRSZ; i++)
 192                 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
 193         best.base = -1;
 194         best.len = 0;
 195         cur.base = -1;
 196         cur.len = 0;
 197         for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 198                 if (words[i] == 0) {
 199                         if (cur.base == -1)
 200                                 cur.base = i, cur.len = 1;
 201                         else
 202                                 cur.len++;
 203                 } else {
 204                         if (cur.base != -1) {
 205                                 if (best.base == -1 || cur.len > best.len)
 206                                         best = cur;
 207                                 cur.base = -1;
 208                         }
 209                 }
 210         }
 211         if (cur.base != -1) {
 212                 if (best.base == -1 || cur.len > best.len)
 213                         best = cur;
 214         }
 215         if (best.base != -1 && best.len < 2)
 216                 best.base = -1;
 217
 218         /*
 219          * Format the result.
 220          */
 221         tp = tmp;
 222         for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 223                 /* Are we inside the best run of 0x00's? */
 224                 if (best.base != -1 && i >= best.base &&
 225                     i < (best.base + best.len)) {
 226                         if (i == best.base)
 227                                 *tp++ = ':';
 228                         continue;
 229                 }
 230                 /* Are we following an initial run of 0x00s or any real hex? */
 231                 if (i != 0)
 232                         *tp++ = ':';
 233                 /* Is this address an encapsulated IPv4? */
 234                 if (i == 6 && best.base == 0 && (best.len == 6 ||
 235                     (best.len == 7 && words[7] != 0x0001) ||
 236                     (best.len == 5 && words[5] == 0xffff))) {
 237                         size_t n;
 238
 239                         if (src[15] || bits == -1 || bits > 120)
 240                                 n = 4;
 241                         else if (src[14] || bits > 112)
 242                                 n = 3;
 243                         else
 244                                 n = 2;
 245                         n = decoct(src+12, n, tp, sizeof tmp - (tp - tmp));
 246                         if (n == 0) {
 247                                 errno = EMSGSIZE;
 248                                 return (NULL);
 249                         }
 250                         tp += strlen(tp);
 251                         break;
 252                 }
 253                 tp += SPRINTF((tp, "%x", words[i]));
 254         }
 255
 256         /* Was it a trailing run of 0x00's? */
 257         if (best.base != -1 && (best.base + best.len) ==
 258             (NS_IN6ADDRSZ / NS_INT16SZ))
 259                 *tp++ = ':';
 260         *tp = '\0';
 261
 262         if (bits != -1)
 263                 tp += SPRINTF((tp, "/%u", bits));
 264
 265         /*
 266          * Check for overflow, copy, and we're done.
 267          */
 268         if ((size_t)(tp - tmp) > size) {
 269                 errno = EMSGSIZE;
 270                 return (NULL);
 271         }
 272         strcpy(dst, tmp);
 273         return (dst);
 274 }
 275
 276 #undef inet_cidr_ntop
 277 #pragma weak inet_cidr_ntop = __inet_cidr_ntop