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