external/bsd/bind/dist/lib/dns/rdataslab.c

   1 /*      $NetBSD$        */
   2
   3 /*
   4  * Copyright (C) 2004-2009  Internet Systems Consortium, Inc. ("ISC")
   5  * Copyright (C) 1999-2003  Internet Software Consortium.
   6  *
   7  * Permission to use, copy, modify, and/or distribute this software for any
   8  * purpose with or without fee is hereby granted, provided that the above
   9  * copyright notice and this permission notice appear in all copies.
  10  *
  11  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
  12  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  13  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  14  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  15  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  16  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  17  * PERFORMANCE OF THIS SOFTWARE.
  18  */
  19
  20 /* Id: rdataslab.c,v 1.50 2009/01/17 23:47:43 tbox Exp */
  21
  22 /*! \file */
  23
  24 #include <config.h>
  25
  26 #include <stdlib.h>
  27
  28 #include <isc/mem.h>
  29 #include <isc/region.h>
  30 #include <isc/string.h>         /* Required for HP/UX (and others?) */
  31 #include <isc/util.h>
  32
  33 #include <dns/result.h>
  34 #include <dns/rdata.h>
  35 #include <dns/rdataset.h>
  36 #include <dns/rdataslab.h>
  37
  38 /*
  39  * The rdataslab structure allows iteration to occur in both load order
  40  * and DNSSEC order.  The structure is as follows:
  41  *
  42  *      header          (reservelen bytes)
  43  *      record count    (2 bytes)
  44  *      offset table    (4 x record count bytes in load order)
  45  *      data records
  46  *              data length     (2 bytes)
  47  *              order           (2 bytes)
  48  *              meta data       (1 byte for RRSIG's)
  49  *              data            (data length bytes)
  50  *
  51  * If DNS_RDATASET_FIXED is defined to be zero (0) the format of a
  52  * rdataslab is as follows:
  53  *
  54  *      header          (reservelen bytes)
  55  *      record count    (2 bytes)
  56  *      data records
  57  *              data length     (2 bytes)
  58  *              data            (data length bytes)
  59  *
  60  * Offsets are from the end of the header.
  61  *
  62  * Load order traversal is performed by walking the offset table to find
  63  * the start of the record (DNS_RDATASET_FIXED = 1).
  64  *
  65  * DNSSEC order traversal is performed by walking the data records.
  66  *
  67  * The order is stored with record to allow for efficient reconstruction
  68  * of the offset table following a merge or subtraction.
  69  *
  70  * The iterator methods here currently only support DNSSEC order iteration.
  71  *
  72  * The iterator methods in rbtdb support both load order and DNSSEC order
  73  * iteration.
  74  *
  75  * WARNING:
  76  *      rbtdb.c directly interacts with the slab's raw structures.  If the
  77  *      structure changes then rbtdb.c also needs to be updated to reflect
  78  *      the changes.  See the areas tagged with "RDATASLAB".
  79  */
  80
  81 struct xrdata {
  82         dns_rdata_t     rdata;
  83         unsigned int    order;
  84 };
  85
  86 /*% Note: the "const void *" are just to make qsort happy.  */
  87 static int
  88 compare_rdata(const void *p1, const void *p2) {
  89         const struct xrdata *x1 = p1;
  90         const struct xrdata *x2 = p2;
  91         return (dns_rdata_compare(&x1->rdata, &x2->rdata));
  92 }
  93
  94 #if DNS_RDATASET_FIXED
  95 static void
  96 fillin_offsets(unsigned char *offsetbase, unsigned int *offsettable,
  97                unsigned length)
  98 {
  99         unsigned int i, j;
 100         unsigned char *raw;
 101
 102         for (i = 0, j = 0; i < length; i++) {
 103
 104                 if (offsettable[i] == 0)
 105                         continue;
 106
 107                 /*
 108                  * Fill in offset table.
 109                  */
 110                 raw = &offsetbase[j*4 + 2];
 111                 *raw++ = (offsettable[i] & 0xff000000) >> 24;
 112                 *raw++ = (offsettable[i] & 0xff0000) >> 16;
 113                 *raw++ = (offsettable[i] & 0xff00) >> 8;
 114                 *raw = offsettable[i] & 0xff;
 115
 116                 /*
 117                  * Fill in table index.
 118                  */
 119                 raw = offsetbase + offsettable[i] + 2;
 120                 *raw++ = (j & 0xff00) >> 8;
 121                 *raw = j++ & 0xff;
 122         }
 123 }
 124 #endif
 125
 126 isc_result_t
 127 dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
 128                            isc_region_t *region, unsigned int reservelen)
 129 {
 130         struct xrdata  *x;
 131         unsigned char  *rawbuf;
 132 #if DNS_RDATASET_FIXED
 133         unsigned char  *offsetbase;
 134 #endif
 135         unsigned int    buflen;
 136         isc_result_t    result;
 137         unsigned int    nitems;
 138         unsigned int    nalloc;
 139         unsigned int    i;
 140 #if DNS_RDATASET_FIXED
 141         unsigned int   *offsettable;
 142 #endif
 143         unsigned int    length;
 144
 145         buflen = reservelen + 2;
 146
 147         nalloc = dns_rdataset_count(rdataset);
 148         nitems = nalloc;
 149         if (nitems == 0)
 150                 return (ISC_R_FAILURE);
 151
 152         if (nalloc > 0xffff)
 153                 return (ISC_R_NOSPACE);
 154
 155         x = isc_mem_get(mctx, nalloc * sizeof(struct xrdata));
 156         if (x == NULL)
 157                 return (ISC_R_NOMEMORY);
 158
 159         /*
 160          * Save all of the rdata members into an array.
 161          */
 162         result = dns_rdataset_first(rdataset);
 163         if (result != ISC_R_SUCCESS)
 164                 goto free_rdatas;
 165         for (i = 0; i < nalloc && result == ISC_R_SUCCESS; i++) {
 166                 INSIST(result == ISC_R_SUCCESS);
 167                 dns_rdata_init(&x[i].rdata);
 168                 dns_rdataset_current(rdataset, &x[i].rdata);
 169 #if DNS_RDATASET_FIXED
 170                 x[i].order = i;
 171 #endif
 172                 result = dns_rdataset_next(rdataset);
 173         }
 174         if (result != ISC_R_NOMORE)
 175                 goto free_rdatas;
 176         if (i != nalloc) {
 177                 /*
 178                  * Somehow we iterated over fewer rdatas than
 179                  * dns_rdataset_count() said there were!
 180                  */
 181                 result = ISC_R_FAILURE;
 182                 goto free_rdatas;
 183         }
 184
 185         /*
 186          * Put into DNSSEC order.
 187          */
 188         qsort(x, nalloc, sizeof(struct xrdata), compare_rdata);
 189
 190         /*
 191          * Remove duplicates and compute the total storage required.
 192          *
 193          * If an rdata is not a duplicate, accumulate the storage size
 194          * required for the rdata.  We do not store the class, type, etc,
 195          * just the rdata, so our overhead is 2 bytes for the number of
 196          * records, and 8 for each rdata, (length(2), offset(4) and order(2))
 197          * and then the rdata itself.
 198          */
 199         for (i = 1; i < nalloc; i++) {
 200                 if (compare_rdata(&x[i-1].rdata, &x[i].rdata) == 0) {
 201                         x[i-1].rdata.data = NULL;
 202                         x[i-1].rdata.length = 0;
 203 #if DNS_RDATASET_FIXED
 204                         /*
 205                          * Preserve the least order so A, B, A -> A, B
 206                          * after duplicate removal.
 207                          */
 208                         if (x[i-1].order < x[i].order)
 209                                 x[i].order = x[i-1].order;
 210 #endif
 211                         nitems--;
 212                 } else {
 213 #if DNS_RDATASET_FIXED
 214                         buflen += (8 + x[i-1].rdata.length);
 215 #else
 216                         buflen += (2 + x[i-1].rdata.length);
 217 #endif
 218                         /*
 219                          * Provide space to store the per RR meta data.
 220                          */
 221                         if (rdataset->type == dns_rdatatype_rrsig)
 222                                 buflen++;
 223                 }
 224         }
 225         /*
 226          * Don't forget the last item!
 227          */
 228 #if DNS_RDATASET_FIXED
 229         buflen += (8 + x[i-1].rdata.length);
 230 #else
 231         buflen += (2 + x[i-1].rdata.length);
 232 #endif
 233         /*
 234          * Provide space to store the per RR meta data.
 235          */
 236         if (rdataset->type == dns_rdatatype_rrsig)
 237                 buflen++;
 238
 239         /*
 240          * Ensure that singleton types are actually singletons.
 241          */
 242         if (nitems > 1 && dns_rdatatype_issingleton(rdataset->type)) {
 243                 /*
 244                  * We have a singleton type, but there's more than one
 245                  * RR in the rdataset.
 246                  */
 247                 result = DNS_R_SINGLETON;
 248                 goto free_rdatas;
 249         }
 250
 251         /*
 252          * Allocate the memory, set up a buffer, start copying in
 253          * data.
 254          */
 255         rawbuf = isc_mem_get(mctx, buflen);
 256         if (rawbuf == NULL) {
 257                 result = ISC_R_NOMEMORY;
 258                 goto free_rdatas;
 259         }
 260
 261 #if DNS_RDATASET_FIXED
 262         /* Allocate temporary offset table. */
 263         offsettable = isc_mem_get(mctx, nalloc * sizeof(unsigned int));
 264         if (offsettable == NULL) {
 265                 isc_mem_put(mctx, rawbuf, buflen);
 266                 result = ISC_R_NOMEMORY;
 267                 goto free_rdatas;
 268         }
 269         memset(offsettable, 0, nalloc * sizeof(unsigned int));
 270 #endif
 271
 272         region->base = rawbuf;
 273         region->length = buflen;
 274
 275         rawbuf += reservelen;
 276 #if DNS_RDATASET_FIXED
 277         offsetbase = rawbuf;
 278 #endif
 279
 280         *rawbuf++ = (nitems & 0xff00) >> 8;
 281         *rawbuf++ = (nitems & 0x00ff);
 282
 283 #if DNS_RDATASET_FIXED
 284         /* Skip load order table.  Filled in later. */
 285         rawbuf += nitems * 4;
 286 #endif
 287
 288         for (i = 0; i < nalloc; i++) {
 289                 if (x[i].rdata.data == NULL)
 290                         continue;
 291 #if DNS_RDATASET_FIXED
 292                 offsettable[x[i].order] = rawbuf - offsetbase;
 293 #endif
 294                 length = x[i].rdata.length;
 295                 if (rdataset->type == dns_rdatatype_rrsig)
 296                         length++;
 297                 *rawbuf++ = (length & 0xff00) >> 8;
 298                 *rawbuf++ = (length & 0x00ff);
 299 #if DNS_RDATASET_FIXED
 300                 rawbuf += 2;    /* filled in later */
 301 #endif
 302                 /*
 303                  * Store the per RR meta data.
 304                  */
 305                 if (rdataset->type == dns_rdatatype_rrsig) {
 306                         *rawbuf++ |= (x[i].rdata.flags & DNS_RDATA_OFFLINE) ?
 307                                             DNS_RDATASLAB_OFFLINE : 0;
 308                 }
 309                 memcpy(rawbuf, x[i].rdata.data, x[i].rdata.length);
 310                 rawbuf += x[i].rdata.length;
 311         }
 312
 313 #if DNS_RDATASET_FIXED
 314         fillin_offsets(offsetbase, offsettable, nalloc);
 315         isc_mem_put(mctx, offsettable, nalloc * sizeof(unsigned int));
 316 #endif
 317
 318         result = ISC_R_SUCCESS;
 319
 320  free_rdatas:
 321         isc_mem_put(mctx, x, nalloc * sizeof(struct xrdata));
 322         return (result);
 323 }
 324
 325 static void
 326 rdataset_disassociate(dns_rdataset_t *rdataset) {
 327         UNUSED(rdataset);
 328 }
 329
 330 static isc_result_t
 331 rdataset_first(dns_rdataset_t *rdataset) {
 332         unsigned char *raw = rdataset->private3;
 333         unsigned int count;
 334
 335         count = raw[0] * 256 + raw[1];
 336         if (count == 0) {
 337                 rdataset->private5 = NULL;
 338                 return (ISC_R_NOMORE);
 339         }
 340 #if DNS_RDATASET_FIXED
 341         raw += 2 + (4 * count);
 342 #else
 343         raw += 2;
 344 #endif
 345         /*
 346          * The privateuint4 field is the number of rdata beyond the cursor
 347          * position, so we decrement the total count by one before storing
 348          * it.
 349          */
 350         count--;
 351         rdataset->privateuint4 = count;
 352         rdataset->private5 = raw;
 353
 354         return (ISC_R_SUCCESS);
 355 }
 356
 357 static isc_result_t
 358 rdataset_next(dns_rdataset_t *rdataset) {
 359         unsigned int count;
 360         unsigned int length;
 361         unsigned char *raw;
 362
 363         count = rdataset->privateuint4;
 364         if (count == 0)
 365                 return (ISC_R_NOMORE);
 366         count--;
 367         rdataset->privateuint4 = count;
 368         raw = rdataset->private5;
 369         length = raw[0] * 256 + raw[1];
 370 #if DNS_RDATASET_FIXED
 371         raw += length + 4;
 372 #else
 373         raw += length + 2;
 374 #endif
 375         rdataset->private5 = raw;
 376
 377         return (ISC_R_SUCCESS);
 378 }
 379
 380 static void
 381 rdataset_current(dns_rdataset_t *rdataset, dns_rdata_t *rdata) {
 382         unsigned char *raw = rdataset->private5;
 383         isc_region_t r;
 384         unsigned int length;
 385         unsigned int flags = 0;
 386
 387         REQUIRE(raw != NULL);
 388
 389         length = raw[0] * 256 + raw[1];
 390 #if DNS_RDATASET_FIXED
 391         raw += 4;
 392 #else
 393         raw += 2;
 394 #endif
 395         if (rdataset->type == dns_rdatatype_rrsig) {
 396                 if (*raw & DNS_RDATASLAB_OFFLINE)
 397                         flags |= DNS_RDATA_OFFLINE;
 398                 length--;
 399                 raw++;
 400         }
 401         r.length = length;
 402         r.base = raw;
 403         dns_rdata_fromregion(rdata, rdataset->rdclass, rdataset->type, &r);
 404         rdata->flags |= flags;
 405 }
 406
 407 static void
 408 rdataset_clone(dns_rdataset_t *source, dns_rdataset_t *target) {
 409         *target = *source;
 410
 411         /*
 412          * Reset iterator state.
 413          */
 414         target->privateuint4 = 0;
 415         target->private5 = NULL;
 416 }
 417
 418 static unsigned int
 419 rdataset_count(dns_rdataset_t *rdataset) {
 420         unsigned char *raw = rdataset->private3;
 421         unsigned int count;
 422
 423         count = raw[0] * 256 + raw[1];
 424
 425         return (count);
 426 }
 427
 428 static dns_rdatasetmethods_t rdataset_methods = {
 429         rdataset_disassociate,
 430         rdataset_first,
 431         rdataset_next,
 432         rdataset_current,
 433         rdataset_clone,
 434         rdataset_count,
 435         NULL,
 436         NULL,
 437         NULL,
 438         NULL,
 439         NULL,
 440         NULL,
 441         NULL
 442 };
 443
 444 void
 445 dns_rdataslab_tordataset(unsigned char *slab, unsigned int reservelen,
 446                          dns_rdataclass_t rdclass, dns_rdatatype_t rdtype,
 447                          dns_rdatatype_t covers, dns_ttl_t ttl,
 448                          dns_rdataset_t *rdataset)
 449 {
 450         REQUIRE(slab != NULL);
 451         REQUIRE(!dns_rdataset_isassociated(rdataset));
 452
 453         rdataset->methods = &rdataset_methods;
 454         rdataset->rdclass = rdclass;
 455         rdataset->type = rdtype;
 456         rdataset->covers = covers;
 457         rdataset->ttl = ttl;
 458         rdataset->trust = 0;
 459         rdataset->private1 = NULL;
 460         rdataset->private2 = NULL;
 461         rdataset->private3 = slab + reservelen;
 462
 463         /*
 464          * Reset iterator state.
 465          */
 466         rdataset->privateuint4 = 0;
 467         rdataset->private5 = NULL;
 468 }
 469
 470 unsigned int
 471 dns_rdataslab_size(unsigned char *slab, unsigned int reservelen) {
 472         unsigned int count, length;
 473         unsigned char *current;
 474
 475         REQUIRE(slab != NULL);
 476
 477         current = slab + reservelen;
 478         count = *current++ * 256;
 479         count += *current++;
 480 #if DNS_RDATASET_FIXED
 481         current += (4 * count);
 482 #endif
 483         while (count > 0) {
 484                 count--;
 485                 length = *current++ * 256;
 486                 length += *current++;
 487 #if DNS_RDATASET_FIXED
 488                 current += length + 2;
 489 #else
 490                 current += length;
 491 #endif
 492         }
 493
 494         return ((unsigned int)(current - slab));
 495 }
 496
 497 /*
 498  * Make the dns_rdata_t 'rdata' refer to the slab item
 499  * beginning at '*current', which is part of a slab of type
 500  * 'type' and class 'rdclass', and advance '*current' to
 501  * point to the next item in the slab.
 502  */
 503 static inline void
 504 rdata_from_slab(unsigned char **current,
 505               dns_rdataclass_t rdclass, dns_rdatatype_t type,
 506               dns_rdata_t *rdata)
 507 {
 508         unsigned char *tcurrent = *current;
 509         isc_region_t region;
 510         unsigned int length;
 511         isc_boolean_t offline = ISC_FALSE;
 512
 513         length = *tcurrent++ * 256;
 514         length += *tcurrent++;
 515
 516         if (type == dns_rdatatype_rrsig) {
 517                 if ((*tcurrent & DNS_RDATASLAB_OFFLINE) != 0)
 518                         offline = ISC_TRUE;
 519                 length--;
 520                 tcurrent++;
 521         }
 522         region.length = length;
 523 #if DNS_RDATASET_FIXED
 524         tcurrent += 2;
 525 #endif
 526         region.base = tcurrent;
 527         tcurrent += region.length;
 528         dns_rdata_fromregion(rdata, rdclass, type, &region);
 529         if (offline)
 530                 rdata->flags |= DNS_RDATA_OFFLINE;
 531         *current = tcurrent;
 532 }
 533
 534 /*
 535  * Return true iff 'slab' (slab data of type 'type' and class 'rdclass')
 536  * contains an rdata identical to 'rdata'.  This does case insensitive
 537  * comparisons per DNSSEC.
 538  */
 539 static inline isc_boolean_t
 540 rdata_in_slab(unsigned char *slab, unsigned int reservelen,
 541               dns_rdataclass_t rdclass, dns_rdatatype_t type,
 542               dns_rdata_t *rdata)
 543 {
 544         unsigned int count, i;
 545         unsigned char *current;
 546         dns_rdata_t trdata = DNS_RDATA_INIT;
 547         int n;
 548
 549         current = slab + reservelen;
 550         count = *current++ * 256;
 551         count += *current++;
 552
 553 #if DNS_RDATASET_FIXED
 554         current += (4 * count);
 555 #endif
 556
 557         for (i = 0; i < count; i++) {
 558                 rdata_from_slab(&current, rdclass, type, &trdata);
 559
 560                 n = dns_rdata_compare(&trdata, rdata);
 561                 if (n == 0)
 562                         return (ISC_TRUE);
 563                 if (n > 0)      /* In DNSSEC order. */
 564                         break;
 565                 dns_rdata_reset(&trdata);
 566         }
 567         return (ISC_FALSE);
 568 }
 569
 570 isc_result_t
 571 dns_rdataslab_merge(unsigned char *oslab, unsigned char *nslab,
 572                     unsigned int reservelen, isc_mem_t *mctx,
 573                     dns_rdataclass_t rdclass, dns_rdatatype_t type,
 574                     unsigned int flags, unsigned char **tslabp)
 575 {
 576         unsigned char *ocurrent, *ostart, *ncurrent, *tstart, *tcurrent, *data;
 577         unsigned int ocount, ncount, count, olength, tlength, tcount, length;
 578         dns_rdata_t ordata = DNS_RDATA_INIT;
 579         dns_rdata_t nrdata = DNS_RDATA_INIT;
 580         isc_boolean_t added_something = ISC_FALSE;
 581         unsigned int oadded = 0;
 582         unsigned int nadded = 0;
 583         unsigned int nncount = 0;
 584 #if DNS_RDATASET_FIXED
 585         unsigned int oncount;
 586         unsigned int norder = 0;
 587         unsigned int oorder = 0;
 588         unsigned char *offsetbase;
 589         unsigned int *offsettable;
 590 #endif
 591
 592         /*
 593          * XXX  Need parameter to allow "delete rdatasets in nslab" merge,
 594          * or perhaps another merge routine for this purpose.
 595          */
 596
 597         REQUIRE(tslabp != NULL && *tslabp == NULL);
 598         REQUIRE(oslab != NULL && nslab != NULL);
 599
 600         ocurrent = oslab + reservelen;
 601         ocount = *ocurrent++ * 256;
 602         ocount += *ocurrent++;
 603 #if DNS_RDATASET_FIXED
 604         ocurrent += (4 * ocount);
 605 #endif
 606         ostart = ocurrent;
 607         ncurrent = nslab + reservelen;
 608         ncount = *ncurrent++ * 256;
 609         ncount += *ncurrent++;
 610 #if DNS_RDATASET_FIXED
 611         ncurrent += (4 * ncount);
 612 #endif
 613         INSIST(ocount > 0 && ncount > 0);
 614
 615 #if DNS_RDATASET_FIXED
 616         oncount = ncount;
 617 #endif
 618
 619         /*
 620          * Yes, this is inefficient!
 621          */
 622
 623         /*
 624          * Figure out the length of the old slab's data.
 625          */
 626         olength = 0;
 627         for (count = 0; count < ocount; count++) {
 628                 length = *ocurrent++ * 256;
 629                 length += *ocurrent++;
 630 #if DNS_RDATASET_FIXED
 631                 olength += length + 8;
 632                 ocurrent += length + 2;
 633 #else
 634                 olength += length + 2;
 635                 ocurrent += length;
 636 #endif
 637         }
 638
 639         /*
 640          * Start figuring out the target length and count.
 641          */
 642         tlength = reservelen + 2 + olength;
 643         tcount = ocount;
 644
 645         /*
 646          * Add in the length of rdata in the new slab that aren't in
 647          * the old slab.
 648          */
 649         do {
 650                 dns_rdata_init(&nrdata);
 651                 rdata_from_slab(&ncurrent, rdclass, type, &nrdata);
 652                 if (!rdata_in_slab(oslab, reservelen, rdclass, type, &nrdata))
 653                 {
 654                         /*
 655                          * This rdata isn't in the old slab.
 656                          */
 657 #if DNS_RDATASET_FIXED
 658                         tlength += nrdata.length + 8;
 659 #else
 660                         tlength += nrdata.length + 2;
 661 #endif
 662                         if (type == dns_rdatatype_rrsig)
 663                                 tlength++;
 664                         tcount++;
 665                         nncount++;
 666                         added_something = ISC_TRUE;
 667                 }
 668                 ncount--;
 669         } while (ncount > 0);
 670         ncount = nncount;
 671
 672         if (((flags & DNS_RDATASLAB_EXACT) != 0) &&
 673             (tcount != ncount + ocount))
 674                 return (DNS_R_NOTEXACT);
 675
 676         if (!added_something && (flags & DNS_RDATASLAB_FORCE) == 0)
 677                 return (DNS_R_UNCHANGED);
 678
 679         /*
 680          * Ensure that singleton types are actually singletons.
 681          */
 682         if (tcount > 1 && dns_rdatatype_issingleton(type)) {
 683                 /*
 684                  * We have a singleton type, but there's more than one
 685                  * RR in the rdataset.
 686                  */
 687                 return (DNS_R_SINGLETON);
 688         }
 689
 690         if (tcount > 0xffff)
 691                 return (ISC_R_NOSPACE);
 692
 693         /*
 694          * Copy the reserved area from the new slab.
 695          */
 696         tstart = isc_mem_get(mctx, tlength);
 697         if (tstart == NULL)
 698                 return (ISC_R_NOMEMORY);
 699         memcpy(tstart, nslab, reservelen);
 700         tcurrent = tstart + reservelen;
 701 #if DNS_RDATASET_FIXED
 702         offsetbase = tcurrent;
 703 #endif
 704
 705         /*
 706          * Write the new count.
 707          */
 708         *tcurrent++ = (tcount & 0xff00) >> 8;
 709         *tcurrent++ = (tcount & 0x00ff);
 710
 711 #if DNS_RDATASET_FIXED
 712         /*
 713          * Skip offset table.
 714          */
 715         tcurrent += (tcount * 4);
 716
 717         offsettable = isc_mem_get(mctx,
 718                                   (ocount + oncount) * sizeof(unsigned int));
 719         if (offsettable == NULL) {
 720                 isc_mem_put(mctx, tstart, tlength);
 721                 return (ISC_R_NOMEMORY);
 722         }
 723         memset(offsettable, 0, (ocount + oncount) * sizeof(unsigned int));
 724 #endif
 725
 726         /*
 727          * Merge the two slabs.
 728          */
 729         ocurrent = ostart;
 730         INSIST(ocount != 0);
 731 #if DNS_RDATASET_FIXED
 732         oorder = ocurrent[2] * 256 + ocurrent[3];
 733         INSIST(oorder < ocount);
 734 #endif
 735         rdata_from_slab(&ocurrent, rdclass, type, &ordata);
 736
 737         ncurrent = nslab + reservelen + 2;
 738 #if DNS_RDATASET_FIXED
 739         ncurrent += (4 * oncount);
 740 #endif
 741
 742         if (ncount > 0) {
 743                 do {
 744                         dns_rdata_reset(&nrdata);
 745 #if DNS_RDATASET_FIXED
 746                         norder = ncurrent[2] * 256 + ncurrent[3];
 747
 748                         INSIST(norder < oncount);
 749 #endif
 750                         rdata_from_slab(&ncurrent, rdclass, type, &nrdata);
 751                 } while (rdata_in_slab(oslab, reservelen, rdclass,
 752                                        type, &nrdata));
 753         }
 754
 755         while (oadded < ocount || nadded < ncount) {
 756                 isc_boolean_t fromold;
 757                 if (oadded == ocount)
 758                         fromold = ISC_FALSE;
 759                 else if (nadded == ncount)
 760                         fromold = ISC_TRUE;
 761                 else
 762                         fromold = ISC_TF(compare_rdata(&ordata, &nrdata) < 0);
 763                 if (fromold) {
 764 #if DNS_RDATASET_FIXED
 765                         offsettable[oorder] = tcurrent - offsetbase;
 766 #endif
 767                         length = ordata.length;
 768                         data = ordata.data;
 769                         if (type == dns_rdatatype_rrsig) {
 770                                 length++;
 771                                 data--;
 772                         }
 773                         *tcurrent++ = (length & 0xff00) >> 8;
 774                         *tcurrent++ = (length & 0x00ff);
 775 #if DNS_RDATASET_FIXED
 776                         tcurrent += 2;  /* fill in later */
 777 #endif
 778                         memcpy(tcurrent, data, length);
 779                         tcurrent += length;
 780                         oadded++;
 781                         if (oadded < ocount) {
 782                                 dns_rdata_reset(&ordata);
 783 #if DNS_RDATASET_FIXED
 784                                 oorder = ocurrent[2] * 256 + ocurrent[3];
 785                                 INSIST(oorder < ocount);
 786 #endif
 787                                 rdata_from_slab(&ocurrent, rdclass, type,
 788                                                 &ordata);
 789                         }
 790                 } else {
 791 #if DNS_RDATASET_FIXED
 792                         offsettable[ocount + norder] = tcurrent - offsetbase;
 793 #endif
 794                         length = nrdata.length;
 795                         data = nrdata.data;
 796                         if (type == dns_rdatatype_rrsig) {
 797                                 length++;
 798                                 data--;
 799                         }
 800                         *tcurrent++ = (length & 0xff00) >> 8;
 801                         *tcurrent++ = (length & 0x00ff);
 802 #if DNS_RDATASET_FIXED
 803                         tcurrent += 2;  /* fill in later */
 804 #endif
 805                         memcpy(tcurrent, data, length);
 806                         tcurrent += length;
 807                         nadded++;
 808                         if (nadded < ncount) {
 809                                 do {
 810                                         dns_rdata_reset(&nrdata);
 811 #if DNS_RDATASET_FIXED
 812                                         norder = ncurrent[2] * 256 + ncurrent[3];
 813                                         INSIST(norder < oncount);
 814 #endif
 815                                         rdata_from_slab(&ncurrent, rdclass,
 816                                                         type, &nrdata);
 817                                 } while (rdata_in_slab(oslab, reservelen,
 818                                                        rdclass, type,
 819                                                        &nrdata));
 820                         }
 821                 }
 822         }
 823
 824 #if DNS_RDATASET_FIXED
 825         fillin_offsets(offsetbase, offsettable, ocount + oncount);
 826
 827         isc_mem_put(mctx, offsettable,
 828                     (ocount + oncount) * sizeof(unsigned int));
 829 #endif
 830
 831         INSIST(tcurrent == tstart + tlength);
 832
 833         *tslabp = tstart;
 834
 835         return (ISC_R_SUCCESS);
 836 }
 837
 838 isc_result_t
 839 dns_rdataslab_subtract(unsigned char *mslab, unsigned char *sslab,
 840                        unsigned int reservelen, isc_mem_t *mctx,
 841                        dns_rdataclass_t rdclass, dns_rdatatype_t type,
 842                        unsigned int flags, unsigned char **tslabp)
 843 {
 844         unsigned char *mcurrent, *sstart, *scurrent, *tstart, *tcurrent;
 845         unsigned int mcount, scount, rcount ,count, tlength, tcount, i;
 846         dns_rdata_t srdata = DNS_RDATA_INIT;
 847         dns_rdata_t mrdata = DNS_RDATA_INIT;
 848 #if DNS_RDATASET_FIXED
 849         unsigned char *offsetbase;
 850         unsigned int *offsettable;
 851         unsigned int order;
 852 #endif
 853
 854         REQUIRE(tslabp != NULL && *tslabp == NULL);
 855         REQUIRE(mslab != NULL && sslab != NULL);
 856
 857         mcurrent = mslab + reservelen;
 858         mcount = *mcurrent++ * 256;
 859         mcount += *mcurrent++;
 860         scurrent = sslab + reservelen;
 861         scount = *scurrent++ * 256;
 862         scount += *scurrent++;
 863         INSIST(mcount > 0 && scount > 0);
 864
 865         /*
 866          * Yes, this is inefficient!
 867          */
 868
 869         /*
 870          * Start figuring out the target length and count.
 871          */
 872         tlength = reservelen + 2;
 873         tcount = 0;
 874         rcount = 0;
 875
 876 #if DNS_RDATASET_FIXED
 877         mcurrent += 4 * mcount;
 878         scurrent += 4 * scount;
 879 #endif
 880         sstart = scurrent;
 881
 882         /*
 883          * Add in the length of rdata in the mslab that aren't in
 884          * the sslab.
 885          */
 886         for (i = 0; i < mcount; i++) {
 887                 unsigned char *mrdatabegin = mcurrent;
 888                 rdata_from_slab(&mcurrent, rdclass, type, &mrdata);
 889                 scurrent = sstart;
 890                 for (count = 0; count < scount; count++) {
 891                         dns_rdata_reset(&srdata);
 892                         rdata_from_slab(&scurrent, rdclass, type, &srdata);
 893                         if (dns_rdata_compare(&mrdata, &srdata) == 0)
 894                                 break;
 895                 }
 896                 if (count == scount) {
 897                         /*
 898                          * This rdata isn't in the sslab, and thus isn't
 899                          * being subtracted.
 900                          */
 901                         tlength += mcurrent - mrdatabegin;
 902                         tcount++;
 903                 } else
 904                         rcount++;
 905                 dns_rdata_reset(&mrdata);
 906         }
 907
 908 #if DNS_RDATASET_FIXED
 909         tlength += (4 * tcount);
 910 #endif
 911
 912         /*
 913          * Check that all the records originally existed.  The numeric
 914          * check only works as rdataslabs do not contain duplicates.
 915          */
 916         if (((flags & DNS_RDATASLAB_EXACT) != 0) && (rcount != scount))
 917                 return (DNS_R_NOTEXACT);
 918
 919         /*
 920          * Don't continue if the new rdataslab would be empty.
 921          */
 922         if (tcount == 0)
 923                 return (DNS_R_NXRRSET);
 924
 925         /*
 926          * If nothing is going to change, we can stop.
 927          */
 928         if (rcount == 0)
 929                 return (DNS_R_UNCHANGED);
 930
 931         /*
 932          * Copy the reserved area from the mslab.
 933          */
 934         tstart = isc_mem_get(mctx, tlength);
 935         if (tstart == NULL)
 936                 return (ISC_R_NOMEMORY);
 937         memcpy(tstart, mslab, reservelen);
 938         tcurrent = tstart + reservelen;
 939 #if DNS_RDATASET_FIXED
 940         offsetbase = tcurrent;
 941
 942         offsettable = isc_mem_get(mctx, mcount * sizeof(unsigned int));
 943         if (offsettable == NULL) {
 944                 isc_mem_put(mctx, tstart, tlength);
 945                 return (ISC_R_NOMEMORY);
 946         }
 947         memset(offsettable, 0, mcount * sizeof(unsigned int));
 948 #endif
 949
 950         /*
 951          * Write the new count.
 952          */
 953         *tcurrent++ = (tcount & 0xff00) >> 8;
 954         *tcurrent++ = (tcount & 0x00ff);
 955
 956 #if DNS_RDATASET_FIXED
 957         tcurrent += (4 * tcount);
 958 #endif
 959
 960         /*
 961          * Copy the parts of mslab not in sslab.
 962          */
 963         mcurrent = mslab + reservelen;
 964         mcount = *mcurrent++ * 256;
 965         mcount += *mcurrent++;
 966 #if DNS_RDATASET_FIXED
 967         mcurrent += (4 * mcount);
 968 #endif
 969         for (i = 0; i < mcount; i++) {
 970                 unsigned char *mrdatabegin = mcurrent;
 971 #if DNS_RDATASET_FIXED
 972                 order = mcurrent[2] * 256 + mcurrent[3];
 973                 INSIST(order < mcount);
 974 #endif
 975                 rdata_from_slab(&mcurrent, rdclass, type, &mrdata);
 976                 scurrent = sstart;
 977                 for (count = 0; count < scount; count++) {
 978                         dns_rdata_reset(&srdata);
 979                         rdata_from_slab(&scurrent, rdclass, type, &srdata);
 980                         if (dns_rdata_compare(&mrdata, &srdata) == 0)
 981                                 break;
 982                 }
 983                 if (count == scount) {
 984                         /*
 985                          * This rdata isn't in the sslab, and thus should be
 986                          * copied to the tslab.
 987                          */
 988                         unsigned int length = mcurrent - mrdatabegin;
 989 #if DNS_RDATASET_FIXED
 990                         offsettable[order] = tcurrent - offsetbase;
 991 #endif
 992                         memcpy(tcurrent, mrdatabegin, length);
 993                         tcurrent += length;
 994                 }
 995                 dns_rdata_reset(&mrdata);
 996         }
 997
 998 #if DNS_RDATASET_FIXED
 999         fillin_offsets(offsetbase, offsettable, mcount);
1000
1001         isc_mem_put(mctx, offsettable, mcount * sizeof(unsigned int));
1002 #endif
1003
1004         INSIST(tcurrent == tstart + tlength);
1005
1006         *tslabp = tstart;
1007
1008         return (ISC_R_SUCCESS);
1009 }
1010
1011 isc_boolean_t
1012 dns_rdataslab_equal(unsigned char *slab1, unsigned char *slab2,
1013                     unsigned int reservelen)
1014 {
1015         unsigned char *current1, *current2;
1016         unsigned int count1, count2;
1017         unsigned int length1, length2;
1018
1019         current1 = slab1 + reservelen;
1020         count1 = *current1++ * 256;
1021         count1 += *current1++;
1022
1023         current2 = slab2 + reservelen;
1024         count2 = *current2++ * 256;
1025         count2 += *current2++;
1026
1027         if (count1 != count2)
1028                 return (ISC_FALSE);
1029
1030 #if DNS_RDATASET_FIXED
1031         current1 += (4 * count1);
1032         current2 += (4 * count2);
1033 #endif
1034
1035         while (count1 > 0) {
1036                 length1 = *current1++ * 256;
1037                 length1 += *current1++;
1038
1039                 length2 = *current2++ * 256;
1040                 length2 += *current2++;
1041
1042 #if DNS_RDATASET_FIXED
1043                 current1 += 2;
1044                 current2 += 2;
1045 #endif
1046
1047                 if (length1 != length2 ||
1048                     memcmp(current1, current2, length1) != 0)
1049                         return (ISC_FALSE);
1050
1051                 current1 += length1;
1052                 current2 += length1;
1053
1054                 count1--;
1055         }
1056         return (ISC_TRUE);
1057 }
1058
1059 isc_boolean_t
1060 dns_rdataslab_equalx(unsigned char *slab1, unsigned char *slab2,
1061                      unsigned int reservelen, dns_rdataclass_t rdclass,
1062                      dns_rdatatype_t type)
1063 {
1064         unsigned char *current1, *current2;
1065         unsigned int count1, count2;
1066         dns_rdata_t rdata1 = DNS_RDATA_INIT;
1067         dns_rdata_t rdata2 = DNS_RDATA_INIT;
1068
1069         current1 = slab1 + reservelen;
1070         count1 = *current1++ * 256;
1071         count1 += *current1++;
1072
1073         current2 = slab2 + reservelen;
1074         count2 = *current2++ * 256;
1075         count2 += *current2++;
1076
1077         if (count1 != count2)
1078                 return (ISC_FALSE);
1079
1080 #if DNS_RDATASET_FIXED
1081         current1 += (4 * count1);
1082         current2 += (4 * count2);
1083 #endif
1084
1085         while (count1-- > 0) {
1086                 rdata_from_slab(&current1, rdclass, type, &rdata1);
1087                 rdata_from_slab(&current2, rdclass, type, &rdata2);
1088                 if (dns_rdata_compare(&rdata1, &rdata2) != 0)
1089                         return (ISC_FALSE);
1090                 dns_rdata_reset(&rdata1);
1091                 dns_rdata_reset(&rdata2);
1092         }
1093         return (ISC_TRUE);
1094 }