libc/inet/ntop.c

   1 /*
   2  * Copyright (c) 1996-1999 by Internet Software Consortium.
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
   9  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  10  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  11  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  12  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  13  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  14  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  15  * SOFTWARE.
  16  */
  17
  18 #include <sys/param.h>
  19 #include <sys/types.h>
  20 #include <sys/socket.h>
  21
  22 #include <netinet/in.h>
  23 #include <arpa/inet.h>
  24 #include <arpa/nameser.h>
  25
  26 #include <errno.h>
  27 #include <stdio.h>
  28 #include <string.h>
  29 #include <ctype.h>
  30
  31
  32 /*
  33  * WARNING: Don't even consider trying to compile this on a system where
  34  * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
  35  */
  36
  37
  38 /* const char *
  39  * inet_ntop4(src, dst, size)
  40  *      format an IPv4 address
  41  * return:
  42  *      `dst' (as a const)
  43  * notes:
  44  *      (1) uses no statics
  45  *      (2) takes a u_char* not an in_addr as input
  46  * author:
  47  *      Paul Vixie, 1996.
  48  */
  49 static const char *
  50 inet_ntop4(const u_char *src, char *dst, size_t size)
  51 {
  52         char tmp[sizeof ("255.255.255.255") + 1];
  53         int octet;
  54         int i;
  55
  56         tmp[0] = '\0';
  57
  58         i = 0;
  59         for (octet = 0; octet <= 3; octet++) {
  60
  61 #if 0   /* since src is unsigned char, it will never be > 255 ... */
  62                 if (src[octet] > 255) {
  63                         __set_errno(ENOSPC);
  64                         return NULL;
  65                 }
  66 #endif
  67                 tmp[i++] = '0' + src[octet] / 100;
  68                 if (tmp[i - 1] == '0') {
  69                         tmp[i - 1] = '0' + (src[octet] / 10 % 10);
  70                         if (tmp[i - 1] == '0') i--;
  71                 } else {
  72                         tmp[i++] = '0' + (src[octet] / 10 % 10);
  73                 }
  74                 tmp[i++] = '0' + src[octet] % 10;
  75                 tmp[i++] = '.';
  76         }
  77         tmp[i - 1] = '\0';
  78
  79         if (strlen(tmp) > size) {
  80                 __set_errno(ENOSPC);
  81                 return NULL;
  82         }
  83
  84         return strcpy(dst, tmp);
  85 }
  86
  87
  88 /* const char *
  89  * inet_ntop6(src, dst, size)
  90  *      convert IPv6 binary address into presentation (printable) format
  91  * author:
  92  *      Paul Vixie, 1996.
  93  */
  94
  95 #ifdef __UCLIBC_HAS_IPV6__
  96
  97 static const char *
  98 inet_ntop6(const u_char *src, char *dst, size_t size)
  99 {
 100         /*
 101          * Note that int32_t and int16_t need only be "at least" large enough
 102          * to contain a value of the specified size.  On some systems, like
 103          * Crays, there is no such thing as an integer variable with 16 bits.
 104          * Keep this in mind if you think this function should have been coded
 105          * to use pointer overlays.  All the world's not a VAX.
 106          */
 107         char tmp[sizeof ("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")], *tp;
 108         struct { int base, len; } best = { 0, 0 }, cur = { 0, 0 };
 109         u_int words[8];
 110         int i;
 111
 112         /*
 113          * Preprocess:
 114          *      Copy the input (bytewise) array into a wordwise array.
 115          *      Find the longest run of 0x00's in src[] for :: shorthanding.
 116          */
 117         memset(words, '\0', sizeof words);
 118         for (i = 0; i < 16; i += 2)
 119                 words[i / 2] = (src[i] << 8) | src[i + 1];
 120         best.base = -1;
 121         cur.base = -1;
 122         best.len = best.len; /* shutting up compiler warning */
 123         cur.len = cur.len;   /* shutting up compiler warning */
 124         for (i = 0; i < 8; i++) {
 125                 if (words[i] == 0) {
 126                         if (cur.base == -1)
 127                                 cur.base = i, cur.len = 1;
 128                         else
 129                                 cur.len++;
 130                 } else {
 131                         if (cur.base != -1) {
 132                                 if (best.base == -1 || cur.len > best.len)
 133                                         best = cur;
 134                                 cur.base = -1;
 135                         }
 136                 }
 137         }
 138         if (cur.base != -1) {
 139                 if (best.base == -1 || cur.len > best.len)
 140                         best = cur;
 141         }
 142         if (best.base != -1 && best.len < 2)
 143                 best.base = -1;
 144
 145         /*
 146          * Format the result.
 147          */
 148         tp = tmp;
 149         for (i = 0; i < 8; i++) {
 150                 /* Are we inside the best run of 0x00's? */
 151                 if (best.base != -1 && i >= best.base &&
 152                     i < (best.base + best.len)) {
 153                         if (i == best.base)
 154                                 *tp++ = ':';
 155                         continue;
 156                 }
 157                 /* Are we following an initial run of 0x00s or any real hex? */
 158                 if (i != 0)
 159                         *tp++ = ':';
 160                 /* Is this address an encapsulated IPv4? */
 161                 if (i == 6 && best.base == 0 &&
 162                     (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
 163                         if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
 164                                 return NULL;
 165                         tp += strlen(tp);
 166                         break;
 167                 }
 168                 tp += sprintf(tp, "%x", words[i]);
 169         }
 170         /* Was it a trailing run of 0x00's? */
 171         if (best.base != -1 && (best.base + best.len) == 8)
 172                 *tp++ = ':';
 173         *tp++ = '\0';
 174
 175         /*
 176          * Check for overflow, copy, and we're done.
 177          */
 178         if ((size_t)(tp - tmp) > size) {
 179                 __set_errno(ENOSPC);
 180                 return NULL;
 181         }
 182         return strcpy(dst, tmp);
 183 }
 184 #endif /* __UCLIBC_HAS_IPV6__ */
 185
 186
 187 /* int
 188  * inet_pton4(src, dst)
 189  *      like inet_aton() but without all the hexadecimal and shorthand.
 190  * return:
 191  *      1 if `src' is a valid dotted quad, else 0.
 192  * notice:
 193  *      does not touch `dst' unless it's returning 1.
 194  * author:
 195  *      Paul Vixie, 1996.
 196  */
 197 static int
 198 inet_pton4(const char *src, u_char *dst)
 199 {
 200         int saw_digit, octets, ch;
 201         u_char tmp[4], *tp;
 202
 203         saw_digit = 0;
 204         octets = 0;
 205         *(tp = tmp) = 0;
 206         while ((ch = *src++) != '\0') {
 207
 208                 if (ch >= '0' && ch <= '9') {
 209                         u_int new = *tp * 10 + (ch - '0');
 210
 211                         if (new > 255)
 212                                 return 0;
 213                         *tp = new;
 214                         if (! saw_digit) {
 215                                 if (++octets > 4)
 216                                         return 0;
 217                                 saw_digit = 1;
 218                         }
 219                 } else if (ch == '.' && saw_digit) {
 220                         if (octets == 4)
 221                                 return 0;
 222                         *++tp = 0;
 223                         saw_digit = 0;
 224                 } else
 225                         return 0;
 226         }
 227         if (octets < 4)
 228                 return 0;
 229         memcpy(dst, tmp, 4);
 230         return 1;
 231 }
 232
 233 /* int
 234  * inet_pton6(src, dst)
 235  *      convert presentation level address to network order binary form.
 236  * return:
 237  *      1 if `src' is a valid [RFC1884 2.2] address, else 0.
 238  * notice:
 239  *      (1) does not touch `dst' unless it's returning 1.
 240  *      (2) :: in a full address is silently ignored.
 241  * credit:
 242  *      inspired by Mark Andrews.
 243  * author:
 244  *      Paul Vixie, 1996.
 245  */
 246
 247 #ifdef __UCLIBC_HAS_IPV6__
 248
 249 static int
 250 inet_pton6(const char *src, u_char *dst)
 251 {
 252         static const char xdigits[] = "0123456789abcdef";
 253         u_char tmp[16], *tp, *endp, *colonp;
 254         const char *curtok;
 255         int ch, saw_xdigit;
 256         u_int val;
 257
 258
 259         tp = memset(tmp, '\0', 16);
 260         endp = tp + 16;
 261         colonp = NULL;
 262         /* Leading :: requires some special handling. */
 263         if (*src == ':')
 264                 if (*++src != ':')
 265                         return 0;
 266         curtok = src;
 267         saw_xdigit = 0;
 268         val = 0;
 269         while ((ch = *src++) != '\0') {
 270                 const char *pch;
 271
 272                 /* | 0x20 is cheap tolower(), valid for letters/numbers only */
 273                 pch = strchr(xdigits, (ch | 0x20));
 274                 if (pch != NULL) {
 275                         val <<= 4;
 276                         val |= (pch - xdigits);
 277                         if (val > 0xffff)
 278                                 return 0;
 279                         saw_xdigit = 1;
 280                         continue;
 281                 }
 282                 if (ch == ':') {
 283                         curtok = src;
 284                         if (!saw_xdigit) {
 285                                 if (colonp)
 286                                         return 0;
 287                                 colonp = tp;
 288                                 continue;
 289                         }
 290                         if (*src == '\0')
 291                                 return 0;
 292                         if (tp + 2 > endp)
 293                                 return 0;
 294                         *tp++ = (u_char) (val >> 8);
 295                         *tp++ = (u_char) val;
 296                         saw_xdigit = 0;
 297                         val = 0;
 298                         continue;
 299                 }
 300                 if (ch == '.' && ((tp + 4) <= endp) &&
 301                     inet_pton4(curtok, tp) > 0) {
 302                         tp += 4;
 303                         saw_xdigit = 0;
 304                         break;  /* '\0' was seen by inet_pton4(). */
 305                 }
 306                 return 0;
 307         }
 308         if (saw_xdigit) {
 309                 if (tp + 2 > endp)
 310                         return 0;
 311                 *tp++ = (u_char) (val >> 8);
 312                 *tp++ = (u_char) val;
 313         }
 314         if (colonp != NULL) {
 315                 /*
 316                  * Since some memmove()'s erroneously fail to handle
 317                  * overlapping regions, we'll do the shift by hand.
 318                  */
 319                 const int n = tp - colonp;
 320                 int i;
 321
 322                 if (tp == endp)
 323                         return 0;
 324                 for (i = 1; i <= n; i++) {
 325                         endp[- i] = colonp[n - i];
 326                         colonp[n - i] = 0;
 327                 }
 328                 tp = endp;
 329         }
 330         if (tp != endp)
 331                 return 0;
 332         memcpy(dst, tmp, 16);
 333         return 1;
 334 }
 335
 336 #endif /* __UCLIBC_HAS_IPV6__ */
 337
 338
 339
 340 /* char *
 341  * inet_ntop(af, src, dst, size)
 342  *      convert a network format address to presentation format.
 343  * return:
 344  *      pointer to presentation format address (`dst'), or NULL (see errno).
 345  * author:
 346  *      Paul Vixie, 1996.
 347  */
 348 const char *
 349 inet_ntop(int af, const void *src, char *dst, socklen_t size)
 350 {
 351         switch (af) {
 352         case AF_INET:
 353                 return inet_ntop4(src, dst, size);
 354 #ifdef __UCLIBC_HAS_IPV6__
 355         case AF_INET6:
 356                 return inet_ntop6(src, dst, size);
 357 #endif
 358         default:
 359                 __set_errno(EAFNOSUPPORT);
 360                 return NULL;
 361         }
 362         /* NOTREACHED */
 363 }
 364 libc_hidden_def(inet_ntop)
 365
 366
 367 /* int
 368  * inet_pton(af, src, dst)
 369  *      convert from presentation format (which usually means ASCII printable)
 370  *      to network format (which is usually some kind of binary format).
 371  * return:
 372  *      1 if the address was valid for the specified address family
 373  *      0 if the address wasn't valid (`dst' is untouched in this case)
 374  *      -1 if some other error occurred (`dst' is untouched in this case, too)
 375  * author:
 376  *      Paul Vixie, 1996.
 377  */
 378 int
 379 inet_pton(int af, const char *src, void *dst)
 380 {
 381         switch (af) {
 382         case AF_INET:
 383                 return inet_pton4(src, dst);
 384 #ifdef __UCLIBC_HAS_IPV6__
 385         case AF_INET6:
 386                 return inet_pton6(src, dst);
 387 #endif
 388         default:
 389                 __set_errno(EAFNOSUPPORT);
 390                 return -1;
 391         }
 392         /* NOTREACHED */
 393 }
 394 libc_hidden_def(inet_pton)