lib/libc/inet/inet_cidr_pton.c

   1 /*
   2  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (c) 1998,1999 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  * $Id: inet_cidr_pton.c,v 1.6 2005/04/27 04:56:19 sra Exp $
  18  */
  19
  20 #include "port_before.h"
  21
  22 #include <sys/types.h>
  23 #include <sys/socket.h>
  24 #include <netinet/in.h>
  25 #include <arpa/nameser.h>
  26 #include <arpa/inet.h>
  27
  28 #include <assert.h>
  29 #include <ctype.h>
  30 #include <errno.h>
  31 #include <stdio.h>
  32 #include <string.h>
  33 #include <stdlib.h>
  34
  35 #include "port_after.h"
  36
  37 static int      inet_cidr_pton_ipv4(const char *src, u_char *dst,
  38                                          int *bits, int ipv6);
  39 static int      inet_cidr_pton_ipv6(const char *src, u_char *dst,
  40                                          int *bits);
  41
  42 static int      getbits(const char *, int ipv6);
  43
  44 /*%
  45  * int
  46  * inet_cidr_pton(af, src, dst, *bits)
  47  *      convert network address from presentation to network format.
  48  *      accepts inet_pton()'s input for this "af" plus trailing "/CIDR".
  49  *      "dst" is assumed large enough for its "af".  "bits" is set to the
  50  *      /CIDR prefix length, which can have defaults (like /32 for IPv4).
  51  * return:
  52  *      -1 if an error occurred (inspect errno; ENOENT means bad format).
  53  *      0 if successful conversion occurred.
  54  * note:
  55  *      192.5.5.1/28 has a nonzero host part, which means it isn't a network
  56  *      as called for by inet_net_pton() but it can be a host address with
  57  *      an included netmask.
  58  * author:
  59  *      Paul Vixie (ISC), October 1998
  60  */
  61 int
  62 inet_cidr_pton(int af, const char *src, void *dst, int *bits) {
  63         switch (af) {
  64         case AF_INET:
  65                 return (inet_cidr_pton_ipv4(src, dst, bits, 0));
  66         case AF_INET6:
  67                 return (inet_cidr_pton_ipv6(src, dst, bits));
  68         default:
  69                 errno = EAFNOSUPPORT;
  70                 return (-1);
  71         }
  72 }
  73
  74 static const char digits[] = "0123456789";
  75
  76 static int
  77 inet_cidr_pton_ipv4(const char *src, u_char *dst, int *pbits, int ipv6) {
  78         const u_char *odst = dst;
  79         int n, ch, tmp, bits;
  80         size_t size = 4;
  81
  82         /* Get the mantissa. */
  83         while (ch = *src++, (isascii(ch) && isdigit(ch))) {
  84                 tmp = 0;
  85                 do {
  86                         n = strchr(digits, ch) - digits;
  87                         assert(n >= 0 && n <= 9);
  88                         tmp *= 10;
  89                         tmp += n;
  90                         if (tmp > 255)
  91                                 goto enoent;
  92                 } while ((ch = *src++) != '\0' && isascii(ch) && isdigit(ch));
  93                 if (size-- == 0U)
  94                         goto emsgsize;
  95                 *dst++ = (u_char) tmp;
  96                 if (ch == '\0' || ch == '/')
  97                         break;
  98                 if (ch != '.')
  99                         goto enoent;
 100         }
 101
 102         /* Get the prefix length if any. */
 103         bits = -1;
 104         if (ch == '/' && dst > odst) {
 105                 bits = getbits(src, ipv6);
 106                 if (bits == -2)
 107                         goto enoent;
 108         } else if (ch != '\0')
 109                 goto enoent;
 110
 111         /* Prefix length can default to /32 only if all four octets spec'd. */
 112         if (bits == -1) {
 113                 if (dst - odst == 4)
 114                         bits = ipv6 ? 128 : 32;
 115                 else
 116                         goto enoent;
 117         }
 118
 119         /* If nothing was written to the destination, we found no address. */
 120         if (dst == odst)
 121                 goto enoent;
 122
 123         /* If prefix length overspecifies mantissa, life is bad. */
 124         if (((bits - (ipv6 ? 96 : 0)) / 8) > (dst - odst))
 125                 goto enoent;
 126
 127         /* Extend address to four octets. */
 128         while (size-- > 0U)
 129                 *dst++ = 0;
 130
 131         *pbits = bits;
 132         return (0);
 133
 134  enoent:
 135         errno = ENOENT;
 136         return (-1);
 137
 138  emsgsize:
 139         errno = EMSGSIZE;
 140         return (-1);
 141 }
 142
 143 static int
 144 inet_cidr_pton_ipv6(const char *src, u_char *dst, int *pbits) {
 145         static const char xdigits_l[] = "0123456789abcdef",
 146                           xdigits_u[] = "0123456789ABCDEF";
 147         u_char tmp[NS_IN6ADDRSZ], *tp, *endp, *colonp;
 148         const char *xdigits, *curtok;
 149         int ch, saw_xdigit;
 150         u_int val;
 151         int bits;
 152
 153         memset((tp = tmp), '\0', NS_IN6ADDRSZ);
 154         endp = tp + NS_IN6ADDRSZ;
 155         colonp = NULL;
 156         /* Leading :: requires some special handling. */
 157         if (*src == ':')
 158                 if (*++src != ':')
 159                         return (0);
 160         curtok = src;
 161         saw_xdigit = 0;
 162         val = 0;
 163         bits = -1;
 164         while ((ch = *src++) != '\0') {
 165                 const char *pch;
 166
 167                 if ((pch = strchr((xdigits = xdigits_l), ch)) == NULL)
 168                         pch = strchr((xdigits = xdigits_u), ch);
 169                 if (pch != NULL) {
 170                         val <<= 4;
 171                         val |= (pch - xdigits);
 172                         if (val > 0xffff)
 173                                 return (0);
 174                         saw_xdigit = 1;
 175                         continue;
 176                 }
 177                 if (ch == ':') {
 178                         curtok = src;
 179                         if (!saw_xdigit) {
 180                                 if (colonp)
 181                                         return (0);
 182                                 colonp = tp;
 183                                 continue;
 184                         } else if (*src == '\0') {
 185                                 return (0);
 186                         }
 187                         if (tp + NS_INT16SZ > endp)
 188                                 return (0);
 189                         *tp++ = (u_char) (val >> 8) & 0xff;
 190                         *tp++ = (u_char) val & 0xff;
 191                         saw_xdigit = 0;
 192                         val = 0;
 193                         continue;
 194                 }
 195                 if (ch == '.' && ((tp + NS_INADDRSZ) <= endp) &&
 196                     inet_cidr_pton_ipv4(curtok, tp, &bits, 1) == 0) {
 197                         tp += NS_INADDRSZ;
 198                         saw_xdigit = 0;
 199                         break;  /*%< '\\0' was seen by inet_pton4(). */
 200                 }
 201                 if (ch == '/') {
 202                         bits = getbits(src, 1);
 203                         if (bits == -2)
 204                                 goto enoent;
 205                         break;
 206                 }
 207                 goto enoent;
 208         }
 209         if (saw_xdigit) {
 210                 if (tp + NS_INT16SZ > endp)
 211                         goto emsgsize;
 212                 *tp++ = (u_char) (val >> 8) & 0xff;
 213                 *tp++ = (u_char) val & 0xff;
 214         }
 215         if (colonp != NULL) {
 216                 /*
 217                  * Since some memmove()'s erroneously fail to handle
 218                  * overlapping regions, we'll do the shift by hand.
 219                  */
 220                 const int n = tp - colonp;
 221                 int i;
 222
 223                 if (tp == endp)
 224                         goto enoent;
 225                 for (i = 1; i <= n; i++) {
 226                         endp[- i] = colonp[n - i];
 227                         colonp[n - i] = 0;
 228                 }
 229                 tp = endp;
 230         }
 231
 232         memcpy(dst, tmp, NS_IN6ADDRSZ);
 233
 234         *pbits = bits;
 235         return (0);
 236
 237  enoent:
 238         errno = ENOENT;
 239         return (-1);
 240
 241  emsgsize:
 242         errno = EMSGSIZE;
 243         return (-1);
 244 }
 245
 246 static int
 247 getbits(const char *src, int ipv6) {
 248         int bits = 0;
 249         char *cp, ch;
 250
 251         if (*src == '\0')                       /*%< syntax */
 252                 return (-2);
 253         do {
 254                 ch = *src++;
 255                 cp = strchr(digits, ch);
 256                 if (cp == NULL)                 /*%< syntax */
 257                         return (-2);
 258                 bits *= 10;
 259                 bits += cp - digits;
 260                 if (bits == 0 && *src != '\0')  /*%< no leading zeros */
 261                         return (-2);
 262                 if (bits > (ipv6 ? 128 : 32))   /*%< range error */
 263                         return (-2);
 264         } while (*src != '\0');
 265
 266         return (bits);
 267 }