dns.subproj/res_comp.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * ++Copyright++ 1985, 1993
  27  * -
  28  * Copyright (c) 1985, 1993
  29  *    The Regents of the University of California.  All rights reserved.
  30  *
  31  * Redistribution and use in source and binary forms, with or without
  32  * modification, are permitted provided that the following conditions
  33  * are met:
  34  * 1. Redistributions of source code must retain the above copyright
  35  *    notice, this list of conditions and the following disclaimer.
  36  * 2. Redistributions in binary form must reproduce the above copyright
  37  *    notice, this list of conditions and the following disclaimer in the
  38  *    documentation and/or other materials provided with the distribution.
  39  * 3. All advertising materials mentioning features or use of this software
  40  *    must display the following acknowledgement:
  41  *      This product includes software developed by the University of
  42  *      California, Berkeley and its contributors.
  43  * 4. Neither the name of the University nor the names of its contributors
  44  *    may be used to endorse or promote products derived from this software
  45  *    without specific prior written permission.
  46  *
  47  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  48  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  49  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  50  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  51  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  52  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  53  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  54  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  55  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  56  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  57  * SUCH DAMAGE.
  58  * -
  59  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  60  *
  61  * Permission to use, copy, modify, and distribute this software for any
  62  * purpose with or without fee is hereby granted, provided that the above
  63  * copyright notice and this permission notice appear in all copies, and that
  64  * the name of Digital Equipment Corporation not be used in advertising or
  65  * publicity pertaining to distribution of the document or software without
  66  * specific, written prior permission.
  67  *
  68  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  69  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  70  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  71  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  72  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  73  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  74  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  75  * SOFTWARE.
  76  * -
  77  * --Copyright--
  78  */
  79
  80 #if defined(LIBC_SCCS) && !defined(lint)
  81 static char sccsid[] = "@(#)res_comp.c  8.1 (Berkeley) 6/4/93";
  82 static char rcsid[] = "$Id: res_comp.c,v 1.4 2003/02/18 17:29:24 majka Exp $";
  83 #endif /* LIBC_SCCS and not lint */
  84
  85 #include <sys/param.h>
  86 #include <netinet/in.h>
  87 #include <arpa/nameser8_compat.h>
  88
  89 #include <stdio.h>
  90 #include <resolv8_compat.h>
  91 #include <ctype.h>
  92
  93 #if defined(BSD) && (BSD >= 199103)
  94 # include <unistd.h>
  95 # include <string.h>
  96 #else
  97 # include "portability.h"
  98 #endif
  99
 100 static int      dn_find __P((u_char *exp_dn, u_char *msg,
 101                              u_char **dnptrs, u_char **lastdnptr));
 102
 103 /*
 104  * Expand compressed domain name 'comp_dn' to full domain name.
 105  * 'msg' is a pointer to the begining of the message,
 106  * 'eomorig' points to the first location after the message,
 107  * 'exp_dn' is a pointer to a buffer of size 'length' for the result.
 108  * Return size of compressed name or -1 if there was an error.
 109  */
 110 int
 111 dn_expand(msg, eomorig, comp_dn, exp_dn, length)
 112         const u_char *msg, *eomorig, *comp_dn;
 113         char *exp_dn;
 114         int length;
 115 {
 116         register const u_char *cp;
 117         register char *dn;
 118         register int n, c;
 119         char *eom;
 120         int len = -1, checked = 0;
 121
 122         dn = exp_dn;
 123         cp = comp_dn;
 124         eom = exp_dn + length;
 125         /*
 126          * fetch next label in domain name
 127          */
 128         while ((n = *cp++)) {
 129                 /*
 130                  * Check for indirection
 131                  */
 132                 switch (n & INDIR_MASK) {
 133                 case 0:
 134                         if (dn != exp_dn) {
 135                                 if (dn >= eom)
 136                                         return (-1);
 137                                 *dn++ = '.';
 138                         }
 139                         if (dn+n >= eom)
 140                                 return (-1);
 141                         checked += n + 1;
 142                         while (--n >= 0) {
 143                                 if ((c = *cp++) == '.') {
 144                                         if (dn + n + 2 >= eom)
 145                                                 return (-1);
 146                                         *dn++ = '\\';
 147                                 }
 148                                 *dn++ = c;
 149                                 if (cp >= eomorig)      /* out of range */
 150                                         return (-1);
 151                         }
 152                         break;
 153
 154                 case INDIR_MASK:
 155                         if (len < 0)
 156                                 len = cp - comp_dn + 1;
 157                         cp = msg + (((n & 0x3f) << 8) | (*cp & 0xff));
 158                         if (cp < msg || cp >= eomorig)  /* out of range */
 159                                 return (-1);
 160                         checked += 2;
 161                         /*
 162                          * Check for loops in the compressed name;
 163                          * if we've looked at the whole message,
 164                          * there must be a loop.
 165                          */
 166                         if (checked >= eomorig - msg)
 167                                 return (-1);
 168                         break;
 169
 170                 default:
 171                         return (-1);                    /* flag error */
 172                 }
 173         }
 174         *dn = '\0';
 175         for (dn = exp_dn; (c = *dn) != '\0'; dn++)
 176                 if (isascii(c) && isspace(c))
 177                         return (-1);
 178         if (len < 0)
 179                 len = cp - comp_dn;
 180         return (len);
 181 }
 182
 183 /*
 184  * Compress domain name 'exp_dn' into 'comp_dn'.
 185  * Return the size of the compressed name or -1.
 186  * 'length' is the size of the array pointed to by 'comp_dn'.
 187  * 'dnptrs' is a list of pointers to previous compressed names. dnptrs[0]
 188  * is a pointer to the beginning of the message. The list ends with NULL.
 189  * 'lastdnptr' is a pointer to the end of the arrary pointed to
 190  * by 'dnptrs'. Side effect is to update the list of pointers for
 191  * labels inserted into the message as we compress the name.
 192  * If 'dnptr' is NULL, we don't try to compress names. If 'lastdnptr'
 193  * is NULL, we don't update the list.
 194  */
 195 int
 196 dn_comp(exp_dn, comp_dn, length, dnptrs, lastdnptr)
 197         const char *exp_dn;
 198         u_char *comp_dn, **dnptrs, **lastdnptr;
 199         int length;
 200 {
 201         register u_char *cp, *dn;
 202         register int c, l;
 203         u_char **cpp, **lpp, *sp, *eob;
 204         u_char *msg;
 205
 206         dn = (u_char *)exp_dn;
 207         cp = comp_dn;
 208         eob = cp + length;
 209         lpp = cpp = NULL;
 210         if (dnptrs != NULL) {
 211                 if ((msg = *dnptrs++) != NULL) {
 212                         for (cpp = dnptrs; *cpp != NULL; cpp++)
 213                                 ;
 214                         lpp = cpp;      /* end of list to search */
 215                 }
 216         } else
 217                 msg = NULL;
 218         for (c = *dn++; c != '\0'; ) {
 219                 /* look to see if we can use pointers */
 220                 if (msg != NULL) {
 221                         if ((l = dn_find(dn-1, msg, dnptrs, lpp)) >= 0) {
 222                                 if (cp+1 >= eob)
 223                                         return (-1);
 224                                 *cp++ = (l >> 8) | INDIR_MASK;
 225                                 *cp++ = l % 256;
 226                                 return (cp - comp_dn);
 227                         }
 228                         /* not found, save it */
 229                         if (lastdnptr != NULL && cpp < lastdnptr-1) {
 230                                 *cpp++ = cp;
 231                                 *cpp = NULL;
 232                         }
 233                 }
 234                 sp = cp++;      /* save ptr to length byte */
 235                 do {
 236                         if (c == '.') {
 237                                 c = *dn++;
 238                                 break;
 239                         }
 240                         if (c == '\\') {
 241                                 if ((c = *dn++) == '\0')
 242                                         break;
 243                         }
 244                         if (cp >= eob) {
 245                                 if (msg != NULL)
 246                                         *lpp = NULL;
 247                                 return (-1);
 248                         }
 249                         *cp++ = c;
 250                 } while ((c = *dn++) != '\0');
 251                 /* catch trailing '.'s but not '..' */
 252                 if ((l = cp - sp - 1) == 0 && c == '\0') {
 253                         cp--;
 254                         break;
 255                 }
 256                 if (l <= 0 || l > MAXLABEL) {
 257                         if (msg != NULL)
 258                                 *lpp = NULL;
 259                         return (-1);
 260                 }
 261                 *sp = l;
 262         }
 263         if (cp >= eob) {
 264                 if (msg != NULL)
 265                         *lpp = NULL;
 266                 return (-1);
 267         }
 268         *cp++ = '\0';
 269         return (cp - comp_dn);
 270 }
 271
 272 /*
 273  * Skip over a compressed domain name. Return the size or -1.
 274  */
 275 int
 276 __dn_skipname(comp_dn, eom)
 277         const u_char *comp_dn, *eom;
 278 {
 279         register const u_char *cp;
 280         register int n;
 281
 282         cp = comp_dn;
 283         while (cp < eom && (n = *cp++)) {
 284                 /*
 285                  * check for indirection
 286                  */
 287                 switch (n & INDIR_MASK) {
 288                 case 0:                 /* normal case, n == len */
 289                         cp += n;
 290                         continue;
 291                 case INDIR_MASK:        /* indirection */
 292                         cp++;
 293                         break;
 294                 default:                /* illegal type */
 295                         return (-1);
 296                 }
 297                 break;
 298         }
 299         if (cp > eom)
 300                 return (-1);
 301         return (cp - comp_dn);
 302 }
 303
 304 static int
 305 mklower(ch)
 306         register int ch;
 307 {
 308         if (isascii(ch) && isupper(ch))
 309                 return (tolower(ch));
 310         return (ch);
 311 }
 312
 313 /*
 314  * Search for expanded name from a list of previously compressed names.
 315  * Return the offset from msg if found or -1.
 316  * dnptrs is the pointer to the first name on the list,
 317  * not the pointer to the start of the message.
 318  */
 319 static int
 320 dn_find(exp_dn, msg, dnptrs, lastdnptr)
 321         u_char *exp_dn, *msg;
 322         u_char **dnptrs, **lastdnptr;
 323 {
 324         register u_char *dn, *cp, **cpp;
 325         register int n;
 326         u_char *sp;
 327
 328         for (cpp = dnptrs; cpp < lastdnptr; cpp++) {
 329                 dn = exp_dn;
 330                 sp = cp = *cpp;
 331                 while ((n = *cp++)) {
 332                         /*
 333                          * check for indirection
 334                          */
 335                         switch (n & INDIR_MASK) {
 336                         case 0:         /* normal case, n == len */
 337                                 while (--n >= 0) {
 338                                         if (*dn == '.')
 339                                                 goto next;
 340                                         if (*dn == '\\')
 341                                                 dn++;
 342                                         if (mklower(*dn++) != mklower(*cp++))
 343                                                 goto next;
 344                                 }
 345                                 if ((n = *dn++) == '\0' && *cp == '\0')
 346                                         return (sp - msg);
 347                                 if (n == '.')
 348                                         continue;
 349                                 goto next;
 350
 351                         case INDIR_MASK:        /* indirection */
 352                                 cp = msg + (((n & 0x3f) << 8) | *cp);
 353                                 break;
 354
 355                         default:        /* illegal type */
 356                                 return (-1);
 357                         }
 358                 }
 359                 if (*dn == '\0')
 360                         return (sp - msg);
 361         next:   ;
 362         }
 363         return (-1);
 364 }
 365
 366 /*
 367  * Routines to insert/extract short/long's.
 368  */
 369
 370 u_int16_t
 371 _getshort(msgp)
 372         register const u_char *msgp;
 373 {
 374         register u_int16_t u;
 375
 376         GETSHORT(u, msgp);
 377         return (u);
 378 }
 379
 380 #if defined(__APPLE__)
 381 /*
 382  * nExt machines have some funky library conventions, which we must maintain.
 383  */
 384 u_int16_t
 385 res_getshort(msgp)
 386         register const u_char *msgp;
 387 {
 388         return (_getshort(msgp));
 389 }
 390 #endif
 391
 392 u_int32_t
 393 _getlong(msgp)
 394         register const u_char *msgp;
 395 {
 396         register u_int32_t u;
 397
 398         GETLONG(u, msgp);
 399         return (u);
 400 }
 401
 402 void
 403 #if defined(__STDC__) || defined(__cplusplus)
 404 __putshort(register u_int16_t s, register u_char *msgp) /* must match proto */
 405 #else
 406 __putshort(s, msgp)
 407         register u_int16_t s;
 408         register u_char *msgp;
 409 #endif
 410 {
 411         PUTSHORT(s, msgp);
 412 }
 413
 414 void
 415 __putlong(l, msgp)
 416         register u_int32_t l;
 417         register u_char *msgp;
 418 {
 419         PUTLONG(l, msgp);
 420 }
 421
 422 #ifdef ultrix
 423 /* ultrix 4.0 had some icky packaging in its libc.a.  alias for it here.
 424  * there is more gunk of this kind over in res_debug.c.
 425  */
 426 #undef putshort
 427 void
 428 #if defined(__STDC__) || defined(__cplusplus)
 429 putshort(register u_short s, register u_char *msgp)
 430 #else
 431 putshort(s, msgp)
 432         register u_short s;
 433         register u_char *msgp;
 434 #endif
 435 {
 436         __putshort(s, msgp);
 437 }
 438 #undef putlong
 439 void
 440 putlong(l, msgp)
 441         register u_int32_t l;
 442         register u_char *msgp;
 443 {
 444         __putlong(l, msgp);
 445 }
 446
 447 #undef dn_skipname
 448 dn_skipname(comp_dn, eom)
 449         const u_char *comp_dn, *eom;
 450 {
 451         return (__dn_skipname(comp_dn, eom));
 452 }
 453 #endif /* Ultrix 4.0 hackery */