contrib/bind9/lib/dns/rdataslab.c

   1 /*
   2  * Copyright (C) 2004-2012  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 1999-2003  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and/or 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 WITH
  10  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  11  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  12  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  13  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  14  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  15  * PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 /* $Id$ */
  19
  20 /*! \file */
  21
  22 #include <config.h>
  23
  24 #include <stdlib.h>
  25
  26 #include <isc/mem.h>
  27 #include <isc/region.h>
  28 #include <isc/string.h>         /* Required for HP/UX (and others?) */
  29 #include <isc/util.h>
  30
  31 #include <dns/result.h>
  32 #include <dns/rdata.h>
  33 #include <dns/rdataset.h>
  34 #include <dns/rdataslab.h>
  35
  36 /*
  37  * The rdataslab structure allows iteration to occur in both load order
  38  * and DNSSEC order.  The structure is as follows:
  39  *
  40  *      header          (reservelen bytes)
  41  *      record count    (2 bytes)
  42  *      offset table    (4 x record count bytes in load order)
  43  *      data records
  44  *              data length     (2 bytes)
  45  *              order           (2 bytes)
  46  *              meta data       (1 byte for RRSIG's)
  47  *              data            (data length bytes)
  48  *
  49  * If DNS_RDATASET_FIXED is defined to be zero (0) the format of a
  50  * rdataslab is as follows:
  51  *
  52  *      header          (reservelen bytes)
  53  *      record count    (2 bytes)
  54  *      data records
  55  *              data length     (2 bytes)
  56  *              meta data       (1 byte for RRSIG's)
  57  *              data            (data length bytes)
  58  *
  59  * Offsets are from the end of the header.
  60  *
  61  * Load order traversal is performed by walking the offset table to find
  62  * the start of the record (DNS_RDATASET_FIXED = 1).
  63  *
  64  * DNSSEC order traversal is performed by walking the data records.
  65  *
  66  * The order is stored with record to allow for efficient reconstruction
  67  * of the offset table following a merge or subtraction.
  68  *
  69  * The iterator methods here currently only support DNSSEC order iteration.
  70  *
  71  * The iterator methods in rbtdb support both load order and DNSSEC order
  72  * iteration.
  73  *
  74  * WARNING:
  75  *      rbtdb.c directly interacts with the slab's raw structures.  If the
  76  *      structure changes then rbtdb.c also needs to be updated to reflect
  77  *      the changes.  See the areas tagged with "RDATASLAB".
  78  */
  79
  80 struct xrdata {
  81         dns_rdata_t     rdata;
  82         unsigned int    order;
  83 };
  84
  85 /*% Note: the "const void *" are just to make qsort happy.  */
  86 static int
  87 compare_rdata(const void *p1, const void *p2) {
  88         const struct xrdata *x1 = p1;
  89         const struct xrdata *x2 = p2;
  90         return (dns_rdata_compare(&x1->rdata, &x2->rdata));
  91 }
  92
  93 #if DNS_RDATASET_FIXED
  94 static void
  95 fillin_offsets(unsigned char *offsetbase, unsigned int *offsettable,
  96                unsigned length)
  97 {
  98         unsigned int i, j;
  99         unsigned char *raw;
 100
 101         for (i = 0, j = 0; i < length; i++) {
 102
 103                 if (offsettable[i] == 0)
 104                         continue;
 105
 106                 /*
 107                  * Fill in offset table.
 108                  */
 109                 raw = &offsetbase[j*4 + 2];
 110                 *raw++ = (offsettable[i] & 0xff000000) >> 24;
 111                 *raw++ = (offsettable[i] & 0xff0000) >> 16;
 112                 *raw++ = (offsettable[i] & 0xff00) >> 8;
 113                 *raw = offsettable[i] & 0xff;
 114
 115                 /*
 116                  * Fill in table index.
 117                  */
 118                 raw = offsetbase + offsettable[i] + 2;
 119                 *raw++ = (j & 0xff00) >> 8;
 120                 *raw = j++ & 0xff;
 121         }
 122 }
 123 #endif
 124
 125 isc_result_t
 126 dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
 127                            isc_region_t *region, unsigned int reservelen)
 128 {
 129         /*
 130          * Use &removed as a sentinal pointer for duplicate
 131          * rdata as rdata.data == NULL is valid.
 132          */
 133         static unsigned char removed;
 134         struct xrdata  *x;
 135         unsigned char  *rawbuf;
 136 #if DNS_RDATASET_FIXED
 137         unsigned char  *offsetbase;
 138 #endif
 139         unsigned int    buflen;
 140         isc_result_t    result;
 141         unsigned int    nitems;
 142         unsigned int    nalloc;
 143         unsigned int    i;
 144 #if DNS_RDATASET_FIXED
 145         unsigned int   *offsettable;
 146 #endif
 147         unsigned int    length;
 148
 149         buflen = reservelen + 2;
 150
 151         nalloc = dns_rdataset_count(rdataset);
 152         nitems = nalloc;
 153         if (nitems == 0 && rdataset->type != 0)
 154                 return (ISC_R_FAILURE);
 155
 156         if (nalloc > 0xffff)
 157                 return (ISC_R_NOSPACE);
 158
 159
 160         if (nalloc != 0) {
 161                 x = isc_mem_get(mctx, nalloc * sizeof(struct xrdata));
 162                 if (x == NULL)
 163                         return (ISC_R_NOMEMORY);
 164         } else
 165                 x = NULL;
 166
 167         /*
 168          * Save all of the rdata members into an array.
 169          */
 170         result = dns_rdataset_first(rdataset);
 171         if (result != ISC_R_SUCCESS && result != ISC_R_NOMORE)
 172                 goto free_rdatas;
 173         for (i = 0; i < nalloc && result == ISC_R_SUCCESS; i++) {
 174                 INSIST(result == ISC_R_SUCCESS);
 175                 dns_rdata_init(&x[i].rdata);
 176                 dns_rdataset_current(rdataset, &x[i].rdata);
 177                 INSIST(x[i].rdata.data != &removed);
 178 #if DNS_RDATASET_FIXED
 179                 x[i].order = i;
 180 #endif
 181                 result = dns_rdataset_next(rdataset);
 182         }
 183         if (result != ISC_R_NOMORE)
 184                 goto free_rdatas;
 185         if (i != nalloc) {
 186                 /*
 187                  * Somehow we iterated over fewer rdatas than
 188                  * dns_rdataset_count() said there were!
 189                  */
 190                 result = ISC_R_FAILURE;
 191                 goto free_rdatas;
 192         }
 193
 194         /*
 195          * Put into DNSSEC order.
 196          */
 197         qsort(x, nalloc, sizeof(struct xrdata), compare_rdata);
 198
 199         /*
 200          * Remove duplicates and compute the total storage required.
 201          *
 202          * If an rdata is not a duplicate, accumulate the storage size
 203          * required for the rdata.  We do not store the class, type, etc,
 204          * just the rdata, so our overhead is 2 bytes for the number of
 205          * records, and 8 for each rdata, (length(2), offset(4) and order(2))
 206          * and then the rdata itself.
 207          */
 208         for (i = 1; i < nalloc; i++) {
 209                 if (compare_rdata(&x[i-1].rdata, &x[i].rdata) == 0) {
 210                         x[i-1].rdata.data = &removed;
 211 #if DNS_RDATASET_FIXED
 212                         /*
 213                          * Preserve the least order so A, B, A -> A, B
 214                          * after duplicate removal.
 215                          */
 216                         if (x[i-1].order < x[i].order)
 217                                 x[i].order = x[i-1].order;
 218 #endif
 219                         nitems--;
 220                 } else {
 221 #if DNS_RDATASET_FIXED
 222                         buflen += (8 + x[i-1].rdata.length);
 223 #else
 224                         buflen += (2 + x[i-1].rdata.length);
 225 #endif
 226                         /*
 227                          * Provide space to store the per RR meta data.
 228                          */
 229                         if (rdataset->type == dns_rdatatype_rrsig)
 230                                 buflen++;
 231                 }
 232         }
 233         /*
 234          * Don't forget the last item!
 235          */
 236         if (nalloc != 0) {
 237 #if DNS_RDATASET_FIXED
 238                 buflen += (8 + x[i-1].rdata.length);
 239 #else
 240                 buflen += (2 + x[i-1].rdata.length);
 241 #endif
 242         }
 243
 244         /*
 245          * Provide space to store the per RR meta data.
 246          */
 247         if (rdataset->type == dns_rdatatype_rrsig)
 248                 buflen++;
 249
 250         /*
 251          * Ensure that singleton types are actually singletons.
 252          */
 253         if (nitems > 1 && dns_rdatatype_issingleton(rdataset->type)) {
 254                 /*
 255                  * We have a singleton type, but there's more than one
 256                  * RR in the rdataset.
 257                  */
 258                 result = DNS_R_SINGLETON;
 259                 goto free_rdatas;
 260         }
 261
 262         /*
 263          * Allocate the memory, set up a buffer, start copying in
 264          * data.
 265          */
 266         rawbuf = isc_mem_get(mctx, buflen);
 267         if (rawbuf == NULL) {
 268                 result = ISC_R_NOMEMORY;
 269                 goto free_rdatas;
 270         }
 271
 272 #if DNS_RDATASET_FIXED
 273         /* Allocate temporary offset table. */
 274         offsettable = isc_mem_get(mctx, nalloc * sizeof(unsigned int));
 275         if (offsettable == NULL) {
 276                 isc_mem_put(mctx, rawbuf, buflen);
 277                 result = ISC_R_NOMEMORY;
 278                 goto free_rdatas;
 279         }
 280         memset(offsettable, 0, nalloc * sizeof(unsigned int));
 281 #endif
 282
 283         region->base = rawbuf;
 284         region->length = buflen;
 285
 286         rawbuf += reservelen;
 287 #if DNS_RDATASET_FIXED
 288         offsetbase = rawbuf;
 289 #endif
 290
 291         *rawbuf++ = (nitems & 0xff00) >> 8;
 292         *rawbuf++ = (nitems & 0x00ff);
 293
 294 #if DNS_RDATASET_FIXED
 295         /* Skip load order table.  Filled in later. */
 296         rawbuf += nitems * 4;
 297 #endif
 298
 299         for (i = 0; i < nalloc; i++) {
 300                 if (x[i].rdata.data == &removed)
 301                         continue;
 302 #if DNS_RDATASET_FIXED
 303                 offsettable[x[i].order] = rawbuf - offsetbase;
 304 #endif
 305                 length = x[i].rdata.length;
 306                 if (rdataset->type == dns_rdatatype_rrsig)
 307                         length++;
 308                 INSIST(length <= 0xffff);
 309                 *rawbuf++ = (length & 0xff00) >> 8;
 310                 *rawbuf++ = (length & 0x00ff);
 311 #if DNS_RDATASET_FIXED
 312                 rawbuf += 2;    /* filled in later */
 313 #endif
 314                 /*
 315                  * Store the per RR meta data.
 316                  */
 317                 if (rdataset->type == dns_rdatatype_rrsig) {
 318                         *rawbuf++ |= (x[i].rdata.flags & DNS_RDATA_OFFLINE) ?
 319                                             DNS_RDATASLAB_OFFLINE : 0;
 320                 }
 321                 memcpy(rawbuf, x[i].rdata.data, x[i].rdata.length);
 322                 rawbuf += x[i].rdata.length;
 323         }
 324
 325 #if DNS_RDATASET_FIXED
 326         fillin_offsets(offsetbase, offsettable, nalloc);
 327         isc_mem_put(mctx, offsettable, nalloc * sizeof(unsigned int));
 328 #endif
 329
 330         result = ISC_R_SUCCESS;
 331
 332  free_rdatas:
 333         if (x != NULL)
 334                 isc_mem_put(mctx, x, nalloc * sizeof(struct xrdata));
 335         return (result);
 336 }
 337
 338 static void
 339 rdataset_disassociate(dns_rdataset_t *rdataset) {
 340         UNUSED(rdataset);
 341 }
 342
 343 static isc_result_t
 344 rdataset_first(dns_rdataset_t *rdataset) {
 345         unsigned char *raw = rdataset->private3;
 346         unsigned int count;
 347
 348         count = raw[0] * 256 + raw[1];
 349         if (count == 0) {
 350                 rdataset->private5 = NULL;
 351                 return (ISC_R_NOMORE);
 352         }
 353 #if DNS_RDATASET_FIXED
 354         raw += 2 + (4 * count);
 355 #else
 356         raw += 2;
 357 #endif
 358         /*
 359          * The privateuint4 field is the number of rdata beyond the cursor
 360          * position, so we decrement the total count by one before storing
 361          * it.
 362          */
 363         count--;
 364         rdataset->privateuint4 = count;
 365         rdataset->private5 = raw;
 366
 367         return (ISC_R_SUCCESS);
 368 }
 369
 370 static isc_result_t
 371 rdataset_next(dns_rdataset_t *rdataset) {
 372         unsigned int count;
 373         unsigned int length;
 374         unsigned char *raw;
 375
 376         count = rdataset->privateuint4;
 377         if (count == 0)
 378                 return (ISC_R_NOMORE);
 379         count--;
 380         rdataset->privateuint4 = count;
 381         raw = rdataset->private5;
 382         length = raw[0] * 256 + raw[1];
 383 #if DNS_RDATASET_FIXED
 384         raw += length + 4;
 385 #else
 386         raw += length + 2;
 387 #endif
 388         rdataset->private5 = raw;
 389
 390         return (ISC_R_SUCCESS);
 391 }
 392
 393 static void
 394 rdataset_current(dns_rdataset_t *rdataset, dns_rdata_t *rdata) {
 395         unsigned char *raw = rdataset->private5;
 396         isc_region_t r;
 397         unsigned int length;
 398         unsigned int flags = 0;
 399
 400         REQUIRE(raw != NULL);
 401
 402         length = raw[0] * 256 + raw[1];
 403 #if DNS_RDATASET_FIXED
 404         raw += 4;
 405 #else
 406         raw += 2;
 407 #endif
 408         if (rdataset->type == dns_rdatatype_rrsig) {
 409                 if (*raw & DNS_RDATASLAB_OFFLINE)
 410                         flags |= DNS_RDATA_OFFLINE;
 411                 length--;
 412                 raw++;
 413         }
 414         r.length = length;
 415         r.base = raw;
 416         dns_rdata_fromregion(rdata, rdataset->rdclass, rdataset->type, &r);
 417         rdata->flags |= flags;
 418 }
 419
 420 static void
 421 rdataset_clone(dns_rdataset_t *source, dns_rdataset_t *target) {
 422         *target = *source;
 423
 424         /*
 425          * Reset iterator state.
 426          */
 427         target->privateuint4 = 0;
 428         target->private5 = NULL;
 429 }
 430
 431 static unsigned int
 432 rdataset_count(dns_rdataset_t *rdataset) {
 433         unsigned char *raw = rdataset->private3;
 434         unsigned int count;
 435
 436         count = raw[0] * 256 + raw[1];
 437
 438         return (count);
 439 }
 440
 441 static dns_rdatasetmethods_t rdataset_methods = {
 442         rdataset_disassociate,
 443         rdataset_first,
 444         rdataset_next,
 445         rdataset_current,
 446         rdataset_clone,
 447         rdataset_count,
 448         NULL,
 449         NULL,
 450         NULL,
 451         NULL,
 452         NULL,
 453         NULL,
 454         NULL,
 455         NULL,
 456         NULL
 457 };
 458
 459 void
 460 dns_rdataslab_tordataset(unsigned char *slab, unsigned int reservelen,
 461                          dns_rdataclass_t rdclass, dns_rdatatype_t rdtype,
 462                          dns_rdatatype_t covers, dns_ttl_t ttl,
 463                          dns_rdataset_t *rdataset)
 464 {
 465         REQUIRE(slab != NULL);
 466         REQUIRE(!dns_rdataset_isassociated(rdataset));
 467
 468         rdataset->methods = &rdataset_methods;
 469         rdataset->rdclass = rdclass;
 470         rdataset->type = rdtype;
 471         rdataset->covers = covers;
 472         rdataset->ttl = ttl;
 473         rdataset->trust = 0;
 474         rdataset->private1 = NULL;
 475         rdataset->private2 = NULL;
 476         rdataset->private3 = slab + reservelen;
 477
 478         /*
 479          * Reset iterator state.
 480          */
 481         rdataset->privateuint4 = 0;
 482         rdataset->private5 = NULL;
 483 }
 484
 485 unsigned int
 486 dns_rdataslab_size(unsigned char *slab, unsigned int reservelen) {
 487         unsigned int count, length;
 488         unsigned char *current;
 489
 490         REQUIRE(slab != NULL);
 491
 492         current = slab + reservelen;
 493         count = *current++ * 256;
 494         count += *current++;
 495 #if DNS_RDATASET_FIXED
 496         current += (4 * count);
 497 #endif
 498         while (count > 0) {
 499                 count--;
 500                 length = *current++ * 256;
 501                 length += *current++;
 502 #if DNS_RDATASET_FIXED
 503                 current += length + 2;
 504 #else
 505                 current += length;
 506 #endif
 507         }
 508
 509         return ((unsigned int)(current - slab));
 510 }
 511
 512 /*
 513  * Make the dns_rdata_t 'rdata' refer to the slab item
 514  * beginning at '*current', which is part of a slab of type
 515  * 'type' and class 'rdclass', and advance '*current' to
 516  * point to the next item in the slab.
 517  */
 518 static inline void
 519 rdata_from_slab(unsigned char **current,
 520               dns_rdataclass_t rdclass, dns_rdatatype_t type,
 521               dns_rdata_t *rdata)
 522 {
 523         unsigned char *tcurrent = *current;
 524         isc_region_t region;
 525         unsigned int length;
 526         isc_boolean_t offline = ISC_FALSE;
 527
 528         length = *tcurrent++ * 256;
 529         length += *tcurrent++;
 530
 531         if (type == dns_rdatatype_rrsig) {
 532                 if ((*tcurrent & DNS_RDATASLAB_OFFLINE) != 0)
 533                         offline = ISC_TRUE;
 534                 length--;
 535                 tcurrent++;
 536         }
 537         region.length = length;
 538 #if DNS_RDATASET_FIXED
 539         tcurrent += 2;
 540 #endif
 541         region.base = tcurrent;
 542         tcurrent += region.length;
 543         dns_rdata_fromregion(rdata, rdclass, type, &region);
 544         if (offline)
 545                 rdata->flags |= DNS_RDATA_OFFLINE;
 546         *current = tcurrent;
 547 }
 548
 549 /*
 550  * Return true iff 'slab' (slab data of type 'type' and class 'rdclass')
 551  * contains an rdata identical to 'rdata'.  This does case insensitive
 552  * comparisons per DNSSEC.
 553  */
 554 static inline isc_boolean_t
 555 rdata_in_slab(unsigned char *slab, unsigned int reservelen,
 556               dns_rdataclass_t rdclass, dns_rdatatype_t type,
 557               dns_rdata_t *rdata)
 558 {
 559         unsigned int count, i;
 560         unsigned char *current;
 561         dns_rdata_t trdata = DNS_RDATA_INIT;
 562         int n;
 563
 564         current = slab + reservelen;
 565         count = *current++ * 256;
 566         count += *current++;
 567
 568 #if DNS_RDATASET_FIXED
 569         current += (4 * count);
 570 #endif
 571
 572         for (i = 0; i < count; i++) {
 573                 rdata_from_slab(&current, rdclass, type, &trdata);
 574
 575                 n = dns_rdata_compare(&trdata, rdata);
 576                 if (n == 0)
 577                         return (ISC_TRUE);
 578                 if (n > 0)      /* In DNSSEC order. */
 579                         break;
 580                 dns_rdata_reset(&trdata);
 581         }
 582         return (ISC_FALSE);
 583 }
 584
 585 isc_result_t
 586 dns_rdataslab_merge(unsigned char *oslab, unsigned char *nslab,
 587                     unsigned int reservelen, isc_mem_t *mctx,
 588                     dns_rdataclass_t rdclass, dns_rdatatype_t type,
 589                     unsigned int flags, unsigned char **tslabp)
 590 {
 591         unsigned char *ocurrent, *ostart, *ncurrent, *tstart, *tcurrent, *data;
 592         unsigned int ocount, ncount, count, olength, tlength, tcount, length;
 593         dns_rdata_t ordata = DNS_RDATA_INIT;
 594         dns_rdata_t nrdata = DNS_RDATA_INIT;
 595         isc_boolean_t added_something = ISC_FALSE;
 596         unsigned int oadded = 0;
 597         unsigned int nadded = 0;
 598         unsigned int nncount = 0;
 599 #if DNS_RDATASET_FIXED
 600         unsigned int oncount;
 601         unsigned int norder = 0;
 602         unsigned int oorder = 0;
 603         unsigned char *offsetbase;
 604         unsigned int *offsettable;
 605 #endif
 606
 607         /*
 608          * XXX  Need parameter to allow "delete rdatasets in nslab" merge,
 609          * or perhaps another merge routine for this purpose.
 610          */
 611
 612         REQUIRE(tslabp != NULL && *tslabp == NULL);
 613         REQUIRE(oslab != NULL && nslab != NULL);
 614
 615         ocurrent = oslab + reservelen;
 616         ocount = *ocurrent++ * 256;
 617         ocount += *ocurrent++;
 618 #if DNS_RDATASET_FIXED
 619         ocurrent += (4 * ocount);
 620 #endif
 621         ostart = ocurrent;
 622         ncurrent = nslab + reservelen;
 623         ncount = *ncurrent++ * 256;
 624         ncount += *ncurrent++;
 625 #if DNS_RDATASET_FIXED
 626         ncurrent += (4 * ncount);
 627 #endif
 628         INSIST(ocount > 0 && ncount > 0);
 629
 630 #if DNS_RDATASET_FIXED
 631         oncount = ncount;
 632 #endif
 633
 634         /*
 635          * Yes, this is inefficient!
 636          */
 637
 638         /*
 639          * Figure out the length of the old slab's data.
 640          */
 641         olength = 0;
 642         for (count = 0; count < ocount; count++) {
 643                 length = *ocurrent++ * 256;
 644                 length += *ocurrent++;
 645 #if DNS_RDATASET_FIXED
 646                 olength += length + 8;
 647                 ocurrent += length + 2;
 648 #else
 649                 olength += length + 2;
 650                 ocurrent += length;
 651 #endif
 652         }
 653
 654         /*
 655          * Start figuring out the target length and count.
 656          */
 657         tlength = reservelen + 2 + olength;
 658         tcount = ocount;
 659
 660         /*
 661          * Add in the length of rdata in the new slab that aren't in
 662          * the old slab.
 663          */
 664         do {
 665                 dns_rdata_init(&nrdata);
 666                 rdata_from_slab(&ncurrent, rdclass, type, &nrdata);
 667                 if (!rdata_in_slab(oslab, reservelen, rdclass, type, &nrdata))
 668                 {
 669                         /*
 670                          * This rdata isn't in the old slab.
 671                          */
 672 #if DNS_RDATASET_FIXED
 673                         tlength += nrdata.length + 8;
 674 #else
 675                         tlength += nrdata.length + 2;
 676 #endif
 677                         if (type == dns_rdatatype_rrsig)
 678                                 tlength++;
 679                         tcount++;
 680                         nncount++;
 681                         added_something = ISC_TRUE;
 682                 }
 683                 ncount--;
 684         } while (ncount > 0);
 685         ncount = nncount;
 686
 687         if (((flags & DNS_RDATASLAB_EXACT) != 0) &&
 688             (tcount != ncount + ocount))
 689                 return (DNS_R_NOTEXACT);
 690
 691         if (!added_something && (flags & DNS_RDATASLAB_FORCE) == 0)
 692                 return (DNS_R_UNCHANGED);
 693
 694         /*
 695          * Ensure that singleton types are actually singletons.
 696          */
 697         if (tcount > 1 && dns_rdatatype_issingleton(type)) {
 698                 /*
 699                  * We have a singleton type, but there's more than one
 700                  * RR in the rdataset.
 701                  */
 702                 return (DNS_R_SINGLETON);
 703         }
 704
 705         if (tcount > 0xffff)
 706                 return (ISC_R_NOSPACE);
 707
 708         /*
 709          * Copy the reserved area from the new slab.
 710          */
 711         tstart = isc_mem_get(mctx, tlength);
 712         if (tstart == NULL)
 713                 return (ISC_R_NOMEMORY);
 714         memcpy(tstart, nslab, reservelen);
 715         tcurrent = tstart + reservelen;
 716 #if DNS_RDATASET_FIXED
 717         offsetbase = tcurrent;
 718 #endif
 719
 720         /*
 721          * Write the new count.
 722          */
 723         *tcurrent++ = (tcount & 0xff00) >> 8;
 724         *tcurrent++ = (tcount & 0x00ff);
 725
 726 #if DNS_RDATASET_FIXED
 727         /*
 728          * Skip offset table.
 729          */
 730         tcurrent += (tcount * 4);
 731
 732         offsettable = isc_mem_get(mctx,
 733                                   (ocount + oncount) * sizeof(unsigned int));
 734         if (offsettable == NULL) {
 735                 isc_mem_put(mctx, tstart, tlength);
 736                 return (ISC_R_NOMEMORY);
 737         }
 738         memset(offsettable, 0, (ocount + oncount) * sizeof(unsigned int));
 739 #endif
 740
 741         /*
 742          * Merge the two slabs.
 743          */
 744         ocurrent = ostart;
 745         INSIST(ocount != 0);
 746 #if DNS_RDATASET_FIXED
 747         oorder = ocurrent[2] * 256 + ocurrent[3];
 748         INSIST(oorder < ocount);
 749 #endif
 750         rdata_from_slab(&ocurrent, rdclass, type, &ordata);
 751
 752         ncurrent = nslab + reservelen + 2;
 753 #if DNS_RDATASET_FIXED
 754         ncurrent += (4 * oncount);
 755 #endif
 756
 757         if (ncount > 0) {
 758                 do {
 759                         dns_rdata_reset(&nrdata);
 760 #if DNS_RDATASET_FIXED
 761                         norder = ncurrent[2] * 256 + ncurrent[3];
 762
 763                         INSIST(norder < oncount);
 764 #endif
 765                         rdata_from_slab(&ncurrent, rdclass, type, &nrdata);
 766                 } while (rdata_in_slab(oslab, reservelen, rdclass,
 767                                        type, &nrdata));
 768         }
 769
 770         while (oadded < ocount || nadded < ncount) {
 771                 isc_boolean_t fromold;
 772                 if (oadded == ocount)
 773                         fromold = ISC_FALSE;
 774                 else if (nadded == ncount)
 775                         fromold = ISC_TRUE;
 776                 else
 777                         fromold = ISC_TF(compare_rdata(&ordata, &nrdata) < 0);
 778                 if (fromold) {
 779 #if DNS_RDATASET_FIXED
 780                         offsettable[oorder] = tcurrent - offsetbase;
 781 #endif
 782                         length = ordata.length;
 783                         data = ordata.data;
 784                         if (type == dns_rdatatype_rrsig) {
 785                                 length++;
 786                                 data--;
 787                         }
 788                         *tcurrent++ = (length & 0xff00) >> 8;
 789                         *tcurrent++ = (length & 0x00ff);
 790 #if DNS_RDATASET_FIXED
 791                         tcurrent += 2;  /* fill in later */
 792 #endif
 793                         memcpy(tcurrent, data, length);
 794                         tcurrent += length;
 795                         oadded++;
 796                         if (oadded < ocount) {
 797                                 dns_rdata_reset(&ordata);
 798 #if DNS_RDATASET_FIXED
 799                                 oorder = ocurrent[2] * 256 + ocurrent[3];
 800                                 INSIST(oorder < ocount);
 801 #endif
 802                                 rdata_from_slab(&ocurrent, rdclass, type,
 803                                                 &ordata);
 804                         }
 805                 } else {
 806 #if DNS_RDATASET_FIXED
 807                         offsettable[ocount + norder] = tcurrent - offsetbase;
 808 #endif
 809                         length = nrdata.length;
 810                         data = nrdata.data;
 811                         if (type == dns_rdatatype_rrsig) {
 812                                 length++;
 813                                 data--;
 814                         }
 815                         *tcurrent++ = (length & 0xff00) >> 8;
 816                         *tcurrent++ = (length & 0x00ff);
 817 #if DNS_RDATASET_FIXED
 818                         tcurrent += 2;  /* fill in later */
 819 #endif
 820                         memcpy(tcurrent, data, length);
 821                         tcurrent += length;
 822                         nadded++;
 823                         if (nadded < ncount) {
 824                                 do {
 825                                         dns_rdata_reset(&nrdata);
 826 #if DNS_RDATASET_FIXED
 827                                         norder = ncurrent[2] * 256 + ncurrent[3];
 828                                         INSIST(norder < oncount);
 829 #endif
 830                                         rdata_from_slab(&ncurrent, rdclass,
 831                                                         type, &nrdata);
 832                                 } while (rdata_in_slab(oslab, reservelen,
 833                                                        rdclass, type,
 834                                                        &nrdata));
 835                         }
 836                 }
 837         }
 838
 839 #if DNS_RDATASET_FIXED
 840         fillin_offsets(offsetbase, offsettable, ocount + oncount);
 841
 842         isc_mem_put(mctx, offsettable,
 843                     (ocount + oncount) * sizeof(unsigned int));
 844 #endif
 845
 846         INSIST(tcurrent == tstart + tlength);
 847
 848         *tslabp = tstart;
 849
 850         return (ISC_R_SUCCESS);
 851 }
 852
 853 isc_result_t
 854 dns_rdataslab_subtract(unsigned char *mslab, unsigned char *sslab,
 855                        unsigned int reservelen, isc_mem_t *mctx,
 856                        dns_rdataclass_t rdclass, dns_rdatatype_t type,
 857                        unsigned int flags, unsigned char **tslabp)
 858 {
 859         unsigned char *mcurrent, *sstart, *scurrent, *tstart, *tcurrent;
 860         unsigned int mcount, scount, rcount ,count, tlength, tcount, i;
 861         dns_rdata_t srdata = DNS_RDATA_INIT;
 862         dns_rdata_t mrdata = DNS_RDATA_INIT;
 863 #if DNS_RDATASET_FIXED
 864         unsigned char *offsetbase;
 865         unsigned int *offsettable;
 866         unsigned int order;
 867 #endif
 868
 869         REQUIRE(tslabp != NULL && *tslabp == NULL);
 870         REQUIRE(mslab != NULL && sslab != NULL);
 871
 872         mcurrent = mslab + reservelen;
 873         mcount = *mcurrent++ * 256;
 874         mcount += *mcurrent++;
 875         scurrent = sslab + reservelen;
 876         scount = *scurrent++ * 256;
 877         scount += *scurrent++;
 878         INSIST(mcount > 0 && scount > 0);
 879
 880         /*
 881          * Yes, this is inefficient!
 882          */
 883
 884         /*
 885          * Start figuring out the target length and count.
 886          */
 887         tlength = reservelen + 2;
 888         tcount = 0;
 889         rcount = 0;
 890
 891 #if DNS_RDATASET_FIXED
 892         mcurrent += 4 * mcount;
 893         scurrent += 4 * scount;
 894 #endif
 895         sstart = scurrent;
 896
 897         /*
 898          * Add in the length of rdata in the mslab that aren't in
 899          * the sslab.
 900          */
 901         for (i = 0; i < mcount; i++) {
 902                 unsigned char *mrdatabegin = mcurrent;
 903                 rdata_from_slab(&mcurrent, rdclass, type, &mrdata);
 904                 scurrent = sstart;
 905                 for (count = 0; count < scount; count++) {
 906                         dns_rdata_reset(&srdata);
 907                         rdata_from_slab(&scurrent, rdclass, type, &srdata);
 908                         if (dns_rdata_compare(&mrdata, &srdata) == 0)
 909                                 break;
 910                 }
 911                 if (count == scount) {
 912                         /*
 913                          * This rdata isn't in the sslab, and thus isn't
 914                          * being subtracted.
 915                          */
 916                         tlength += mcurrent - mrdatabegin;
 917                         tcount++;
 918                 } else
 919                         rcount++;
 920                 dns_rdata_reset(&mrdata);
 921         }
 922
 923 #if DNS_RDATASET_FIXED
 924         tlength += (4 * tcount);
 925 #endif
 926
 927         /*
 928          * Check that all the records originally existed.  The numeric
 929          * check only works as rdataslabs do not contain duplicates.
 930          */
 931         if (((flags & DNS_RDATASLAB_EXACT) != 0) && (rcount != scount))
 932                 return (DNS_R_NOTEXACT);
 933
 934         /*
 935          * Don't continue if the new rdataslab would be empty.
 936          */
 937         if (tcount == 0)
 938                 return (DNS_R_NXRRSET);
 939
 940         /*
 941          * If nothing is going to change, we can stop.
 942          */
 943         if (rcount == 0)
 944                 return (DNS_R_UNCHANGED);
 945
 946         /*
 947          * Copy the reserved area from the mslab.
 948          */
 949         tstart = isc_mem_get(mctx, tlength);
 950         if (tstart == NULL)
 951                 return (ISC_R_NOMEMORY);
 952         memcpy(tstart, mslab, reservelen);
 953         tcurrent = tstart + reservelen;
 954 #if DNS_RDATASET_FIXED
 955         offsetbase = tcurrent;
 956
 957         offsettable = isc_mem_get(mctx, mcount * sizeof(unsigned int));
 958         if (offsettable == NULL) {
 959                 isc_mem_put(mctx, tstart, tlength);
 960                 return (ISC_R_NOMEMORY);
 961         }
 962         memset(offsettable, 0, mcount * sizeof(unsigned int));
 963 #endif
 964
 965         /*
 966          * Write the new count.
 967          */
 968         *tcurrent++ = (tcount & 0xff00) >> 8;
 969         *tcurrent++ = (tcount & 0x00ff);
 970
 971 #if DNS_RDATASET_FIXED
 972         tcurrent += (4 * tcount);
 973 #endif
 974
 975         /*
 976          * Copy the parts of mslab not in sslab.
 977          */
 978         mcurrent = mslab + reservelen;
 979         mcount = *mcurrent++ * 256;
 980         mcount += *mcurrent++;
 981 #if DNS_RDATASET_FIXED
 982         mcurrent += (4 * mcount);
 983 #endif
 984         for (i = 0; i < mcount; i++) {
 985                 unsigned char *mrdatabegin = mcurrent;
 986 #if DNS_RDATASET_FIXED
 987                 order = mcurrent[2] * 256 + mcurrent[3];
 988                 INSIST(order < mcount);
 989 #endif
 990                 rdata_from_slab(&mcurrent, rdclass, type, &mrdata);
 991                 scurrent = sstart;
 992                 for (count = 0; count < scount; count++) {
 993                         dns_rdata_reset(&srdata);
 994                         rdata_from_slab(&scurrent, rdclass, type, &srdata);
 995                         if (dns_rdata_compare(&mrdata, &srdata) == 0)
 996                                 break;
 997                 }
 998                 if (count == scount) {
 999                         /*
1000                          * This rdata isn't in the sslab, and thus should be
1001                          * copied to the tslab.
1002                          */
1003                         unsigned int length = mcurrent - mrdatabegin;
1004 #if DNS_RDATASET_FIXED
1005                         offsettable[order] = tcurrent - offsetbase;
1006 #endif
1007                         memcpy(tcurrent, mrdatabegin, length);
1008                         tcurrent += length;
1009                 }
1010                 dns_rdata_reset(&mrdata);
1011         }
1012
1013 #if DNS_RDATASET_FIXED
1014         fillin_offsets(offsetbase, offsettable, mcount);
1015
1016         isc_mem_put(mctx, offsettable, mcount * sizeof(unsigned int));
1017 #endif
1018
1019         INSIST(tcurrent == tstart + tlength);
1020
1021         *tslabp = tstart;
1022
1023         return (ISC_R_SUCCESS);
1024 }
1025
1026 isc_boolean_t
1027 dns_rdataslab_equal(unsigned char *slab1, unsigned char *slab2,
1028                     unsigned int reservelen)
1029 {
1030         unsigned char *current1, *current2;
1031         unsigned int count1, count2;
1032         unsigned int length1, length2;
1033
1034         current1 = slab1 + reservelen;
1035         count1 = *current1++ * 256;
1036         count1 += *current1++;
1037
1038         current2 = slab2 + reservelen;
1039         count2 = *current2++ * 256;
1040         count2 += *current2++;
1041
1042         if (count1 != count2)
1043                 return (ISC_FALSE);
1044
1045 #if DNS_RDATASET_FIXED
1046         current1 += (4 * count1);
1047         current2 += (4 * count2);
1048 #endif
1049
1050         while (count1 > 0) {
1051                 length1 = *current1++ * 256;
1052                 length1 += *current1++;
1053
1054                 length2 = *current2++ * 256;
1055                 length2 += *current2++;
1056
1057 #if DNS_RDATASET_FIXED
1058                 current1 += 2;
1059                 current2 += 2;
1060 #endif
1061
1062                 if (length1 != length2 ||
1063                     memcmp(current1, current2, length1) != 0)
1064                         return (ISC_FALSE);
1065
1066                 current1 += length1;
1067                 current2 += length1;
1068
1069                 count1--;
1070         }
1071         return (ISC_TRUE);
1072 }
1073
1074 isc_boolean_t
1075 dns_rdataslab_equalx(unsigned char *slab1, unsigned char *slab2,
1076                      unsigned int reservelen, dns_rdataclass_t rdclass,
1077                      dns_rdatatype_t type)
1078 {
1079         unsigned char *current1, *current2;
1080         unsigned int count1, count2;
1081         dns_rdata_t rdata1 = DNS_RDATA_INIT;
1082         dns_rdata_t rdata2 = DNS_RDATA_INIT;
1083
1084         current1 = slab1 + reservelen;
1085         count1 = *current1++ * 256;
1086         count1 += *current1++;
1087
1088         current2 = slab2 + reservelen;
1089         count2 = *current2++ * 256;
1090         count2 += *current2++;
1091
1092         if (count1 != count2)
1093                 return (ISC_FALSE);
1094
1095 #if DNS_RDATASET_FIXED
1096         current1 += (4 * count1);
1097         current2 += (4 * count2);
1098 #endif
1099
1100         while (count1-- > 0) {
1101                 rdata_from_slab(&current1, rdclass, type, &rdata1);
1102                 rdata_from_slab(&current2, rdclass, type, &rdata2);
1103                 if (dns_rdata_compare(&rdata1, &rdata2) != 0)
1104                         return (ISC_FALSE);
1105                 dns_rdata_reset(&rdata1);
1106                 dns_rdata_reset(&rdata2);
1107         }
1108         return (ISC_TRUE);
1109 }