lib/libc/inet/inet_cidr_pton.c

   1 /*      $NetBSD: inet_cidr_pton.c,v 1.8 2012/03/20 17:08:13 matt 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_pton.c,v 1.6 2005/04/27 04:56:19 sra Exp";
  24 #else
  25 __RCSID("$NetBSD: inet_cidr_pton.c,v 1.8 2012/03/20 17:08:13 matt Exp $");
  26 #endif
  27 #endif
  28
  29 #include "port_before.h"
  30
  31 #include "namespace.h"
  32 #include <sys/types.h>
  33 #include <sys/socket.h>
  34 #include <netinet/in.h>
  35 #include <arpa/nameser.h>
  36 #include <arpa/inet.h>
  37
  38 #include <isc/assertions.h>
  39 #include <ctype.h>
  40 #include <errno.h>
  41 #include <stdio.h>
  42 #include <string.h>
  43 #include <stddef.h>
  44 #include <stdlib.h>
  45
  46 #include "port_after.h"
  47
  48 #ifdef SPRINTF_CHAR
  49 # define SPRINTF(x) strlen(sprintf/**/x)
  50 #else
  51 # define SPRINTF(x) ((size_t)sprintf x)
  52 #endif
  53
  54 #ifdef __weak_alias
  55 __weak_alias(inet_cidr_pton,_inet_cidr_pton)
  56 #endif
  57
  58 static int      inet_cidr_pton_ipv4(const char *src, u_char *dst,
  59                                          int *bits, int ipv6);
  60 static int      inet_cidr_pton_ipv6(const char *src, u_char *dst, int *bits);
  61
  62 static int      getbits(const char *, int ipv6);
  63
  64 /*%
  65  * int
  66  * inet_cidr_pton(af, src, dst, *bits)
  67  *      convert network address from presentation to network format.
  68  *      accepts inet_pton()'s input for this "af" plus trailing "/CIDR".
  69  *      "dst" is assumed large enough for its "af".  "bits" is set to the
  70  *      /CIDR prefix length, which can have defaults (like /32 for IPv4).
  71  * return:
  72  *      -1 if an error occurred (inspect errno; ENOENT means bad format).
  73  *      0 if successful conversion occurred.
  74  * note:
  75  *      192.5.5.1/28 has a nonzero host part, which means it isn't a network
  76  *      as called for by inet_net_pton() but it can be a host address with
  77  *      an included netmask.
  78  * author:
  79  *      Paul Vixie (ISC), October 1998
  80  */
  81 int
  82 inet_cidr_pton(int af, const char *src, void *dst, int *bits) {
  83         switch (af) {
  84         case AF_INET:
  85                 return (inet_cidr_pton_ipv4(src, dst, bits, 0));
  86         case AF_INET6:
  87                 return (inet_cidr_pton_ipv6(src, dst, bits));
  88         default:
  89                 errno = EAFNOSUPPORT;
  90                 return (-1);
  91         }
  92 }
  93
  94 static const char digits[] = "0123456789";
  95
  96 static int
  97 inet_cidr_pton_ipv4(const char *src, u_char *dst, int *pbits, int ipv6) {
  98         const u_char *odst = dst;
  99         int ch, bits;
 100         ptrdiff_t n, tmp;
 101         size_t size = 4;
 102
 103         /* Get the mantissa. */
 104         while (ch = *src++, (isascii(ch) && isdigit(ch))) {
 105                 tmp = 0;
 106                 do {
 107                         n = strchr(digits, ch) - digits;
 108                         INSIST(n >= 0 && n <= 9);
 109                         tmp *= 10;
 110                         tmp += n;
 111                         if (tmp > 255)
 112                                 goto enoent;
 113                 } while ((ch = *src++) != '\0' && isascii(ch) && isdigit(ch));
 114                 if (size-- == 0U)
 115                         goto emsgsize;
 116                 *dst++ = (u_char) tmp;
 117                 if (ch == '\0' || ch == '/')
 118                         break;
 119                 if (ch != '.')
 120                         goto enoent;
 121         }
 122
 123         /* Get the prefix length if any. */
 124         bits = -1;
 125         if (ch == '/' && dst > odst) {
 126                 bits = getbits(src, ipv6);
 127                 if (bits == -2)
 128                         goto enoent;
 129         } else if (ch != '\0')
 130                 goto enoent;
 131
 132         /* Prefix length can default to /32 only if all four octets spec'd. */
 133         if (bits == -1) {
 134                 if (dst - odst == 4)
 135                         bits = ipv6 ? 128 : 32;
 136                 else
 137                         goto enoent;
 138         }
 139
 140         /* If nothing was written to the destination, we found no address. */
 141         if (dst == odst)
 142                 goto enoent;
 143
 144         /* If prefix length overspecifies mantissa, life is bad. */
 145         if (((bits - (ipv6 ? 96 : 0)) / 8) > (dst - odst))
 146                 goto enoent;
 147
 148         /* Extend address to four octets. */
 149         while (size-- > 0U)
 150                 *dst++ = 0;
 151
 152         *pbits = bits;
 153         return (0);
 154
 155  enoent:
 156         errno = ENOENT;
 157         return (-1);
 158
 159  emsgsize:
 160         errno = EMSGSIZE;
 161         return (-1);
 162 }
 163
 164 static int
 165 inet_cidr_pton_ipv6(const char *src, u_char *dst, int *pbits) {
 166         static const char xdigits_l[] = "0123456789abcdef",
 167                           xdigits_u[] = "0123456789ABCDEF";
 168         u_char tmp[NS_IN6ADDRSZ], *tp, *endp, *colonp;
 169         const char *xdigits, *curtok;
 170         int ch, saw_xdigit;
 171         u_int val;
 172         int bits;
 173
 174         memset((tp = tmp), '\0', NS_IN6ADDRSZ);
 175         endp = tp + NS_IN6ADDRSZ;
 176         colonp = NULL;
 177         /* Leading :: requires some special handling. */
 178         if (*src == ':')
 179                 if (*++src != ':')
 180                         return (0);
 181         curtok = src;
 182         saw_xdigit = 0;
 183         val = 0;
 184         bits = -1;
 185         while ((ch = *src++) != '\0') {
 186                 const char *pch;
 187
 188                 if ((pch = strchr((xdigits = xdigits_l), ch)) == NULL)
 189                         pch = strchr((xdigits = xdigits_u), ch);
 190                 if (pch != NULL) {
 191                         val <<= 4;
 192                         val |= (int)(pch - xdigits);
 193                         if (val > 0xffff)
 194                                 return (0);
 195                         saw_xdigit = 1;
 196                         continue;
 197                 }
 198                 if (ch == ':') {
 199                         curtok = src;
 200                         if (!saw_xdigit) {
 201                                 if (colonp)
 202                                         return (0);
 203                                 colonp = tp;
 204                                 continue;
 205                         } else if (*src == '\0') {
 206                                 return (0);
 207                         }
 208                         if (tp + NS_INT16SZ > endp)
 209                                 return (0);
 210                         *tp++ = (u_char) (val >> 8) & 0xff;
 211                         *tp++ = (u_char) val & 0xff;
 212                         saw_xdigit = 0;
 213                         val = 0;
 214                         continue;
 215                 }
 216                 if (ch == '.' && ((tp + NS_INADDRSZ) <= endp) &&
 217                     inet_cidr_pton_ipv4(curtok, tp, &bits, 1) == 0) {
 218                         tp += NS_INADDRSZ;
 219                         saw_xdigit = 0;
 220                         break;  /*%< '\\0' was seen by inet_pton4(). */
 221                 }
 222                 if (ch == '/') {
 223                         bits = getbits(src, 1);
 224                         if (bits == -2)
 225                                 goto enoent;
 226                         break;
 227                 }
 228                 goto enoent;
 229         }
 230         if (saw_xdigit) {
 231                 if (tp + NS_INT16SZ > endp)
 232                         goto emsgsize;
 233                 *tp++ = (u_char) (val >> 8) & 0xff;
 234                 *tp++ = (u_char) val & 0xff;
 235         }
 236         if (colonp != NULL) {
 237                 /*
 238                  * Since some memmove()'s erroneously fail to handle
 239                  * overlapping regions, we'll do the shift by hand.
 240                  */
 241                 const ptrdiff_t n = tp - colonp;
 242                 int i;
 243
 244                 if (tp == endp)
 245                         goto enoent;
 246                 for (i = 1; i <= n; i++) {
 247                         endp[- i] = colonp[n - i];
 248                         colonp[n - i] = 0;
 249                 }
 250                 tp = endp;
 251         }
 252
 253         memcpy(dst, tmp, NS_IN6ADDRSZ);
 254
 255         *pbits = bits;
 256         return (0);
 257
 258  enoent:
 259         errno = ENOENT;
 260         return (-1);
 261
 262  emsgsize:
 263         errno = EMSGSIZE;
 264         return (-1);
 265 }
 266
 267 static int
 268 getbits(const char *src, int ipv6) {
 269         int bits = 0;
 270         char *cp, ch;
 271
 272         if (*src == '\0')                       /*%< syntax */
 273                 return (-2);
 274         do {
 275                 ch = *src++;
 276                 cp = strchr(digits, ch);
 277                 if (cp == NULL)                 /*%< syntax */
 278                         return (-2);
 279                 bits *= 10;
 280                 bits += (int)(cp - digits);
 281                 if (bits == 0 && *src != '\0')  /*%< no leading zeros */
 282                         return (-2);
 283                 if (bits > (ipv6 ? 128 : 32))   /*%< range error */
 284                         return (-2);
 285         } while (*src != '\0');
 286
 287         return (bits);
 288 }
 289
 290 /*! \file */