contrib/bind-9.2.4rc7/lib/dns/diff.c

   1 /*
   2  * Copyright (C) 2004  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 2000-2002  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and 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: diff.c,v 1.4.2.3 2004/03/09 06:11:01 marka Exp $ */
  19
  20 #include <config.h>
  21
  22 #include <stdlib.h>
  23
  24 #include <isc/buffer.h>
  25 #include <isc/file.h>
  26 #include <isc/mem.h>
  27 #include <isc/string.h>
  28 #include <isc/util.h>
  29
  30 #include <dns/db.h>
  31 #include <dns/diff.h>
  32 #include <dns/log.h>
  33 #include <dns/rdatalist.h>
  34 #include <dns/rdataset.h>
  35 #include <dns/result.h>
  36
  37 #define CHECK(op) \
  38         do { result = (op);                                     \
  39                 if (result != ISC_R_SUCCESS) goto failure;      \
  40         } while (0)
  41
  42 #define DIFF_COMMON_LOGARGS \
  43         dns_lctx, DNS_LOGCATEGORY_GENERAL, DNS_LOGMODULE_DIFF
  44
  45 static dns_rdatatype_t
  46 rdata_covers(dns_rdata_t *rdata) {
  47         return (rdata->type == dns_rdatatype_sig ?
  48                 dns_rdata_covers(rdata) : 0);
  49 }
  50
  51 isc_result_t
  52 dns_difftuple_create(isc_mem_t *mctx,
  53                      dns_diffop_t op, dns_name_t *name, dns_ttl_t ttl,
  54                      dns_rdata_t *rdata, dns_difftuple_t **tp)
  55 {
  56         dns_difftuple_t *t;
  57         unsigned int size;
  58         unsigned char *datap;
  59
  60         REQUIRE(tp != NULL && *tp == NULL);
  61
  62         /*
  63          * Create a new tuple.  The variable-size wire-format name data and
  64          * rdata immediately follow the dns_difftuple_t structure
  65          * in memory.
  66          */
  67         size = sizeof(*t) + name->length + rdata->length;
  68         t = isc_mem_allocate(mctx, size);
  69         if (t == NULL)
  70                 return (ISC_R_NOMEMORY);
  71         t->mctx = mctx;
  72         t->op = op;
  73
  74         datap = (unsigned char *)(t + 1);
  75
  76         memcpy(datap, name->ndata, name->length);
  77         dns_name_init(&t->name, NULL);
  78         dns_name_clone(name, &t->name);
  79         t->name.ndata = datap;
  80         datap += name->length;
  81
  82         t->ttl = ttl;
  83
  84         memcpy(datap, rdata->data, rdata->length);
  85         dns_rdata_init(&t->rdata);
  86         dns_rdata_clone(rdata, &t->rdata);
  87         t->rdata.data = datap;
  88         datap += rdata->length;
  89
  90         ISC_LINK_INIT(&t->rdata, link);
  91         ISC_LINK_INIT(t, link);
  92         t->magic = DNS_DIFFTUPLE_MAGIC;
  93
  94         INSIST(datap == (unsigned char *)t + size);
  95
  96         *tp = t;
  97         return (ISC_R_SUCCESS);
  98 }
  99
 100 void
 101 dns_difftuple_free(dns_difftuple_t **tp) {
 102         dns_difftuple_t *t = *tp;
 103         REQUIRE(DNS_DIFFTUPLE_VALID(t));
 104         dns_name_invalidate(&t->name);
 105         t->magic = 0;
 106         isc_mem_free(t->mctx, t);
 107         *tp = NULL;
 108 }
 109
 110 isc_result_t
 111 dns_difftuple_copy(dns_difftuple_t *orig, dns_difftuple_t **copyp) {
 112         return (dns_difftuple_create(orig->mctx, orig->op, &orig->name,
 113                                      orig->ttl, &orig->rdata, copyp));
 114 }
 115
 116 void
 117 dns_diff_init(isc_mem_t *mctx, dns_diff_t *diff) {
 118         diff->mctx = mctx;
 119         ISC_LIST_INIT(diff->tuples);
 120         diff->magic = DNS_DIFF_MAGIC;
 121 }
 122
 123 void
 124 dns_diff_clear(dns_diff_t *diff) {
 125         dns_difftuple_t *t;
 126         REQUIRE(DNS_DIFF_VALID(diff));
 127         while ((t = ISC_LIST_HEAD(diff->tuples)) != NULL) {
 128                 ISC_LIST_UNLINK(diff->tuples, t, link);
 129                 dns_difftuple_free(&t);
 130         }
 131         ENSURE(ISC_LIST_EMPTY(diff->tuples));
 132 }
 133
 134 void
 135 dns_diff_append(dns_diff_t *diff, dns_difftuple_t **tuplep)
 136 {
 137         ISC_LIST_APPEND(diff->tuples, *tuplep, link);
 138         *tuplep = NULL;
 139 }
 140
 141 /* XXX this is O(N) */
 142
 143 void
 144 dns_diff_appendminimal(dns_diff_t *diff, dns_difftuple_t **tuplep)
 145 {
 146         dns_difftuple_t *ot, *next_ot;
 147
 148         REQUIRE(DNS_DIFF_VALID(diff));
 149         REQUIRE(DNS_DIFFTUPLE_VALID(*tuplep));
 150
 151         /*
 152          * Look for an existing tuple with the same owner name,
 153          * rdata, and TTL.   If we are doing an addition and find a
 154          * deletion or vice versa, remove both the old and the
 155          * new tuple since they cancel each other out (assuming
 156          * that we never delete nonexistent data or add existing
 157          * data).
 158          *
 159          * If we find an old update of the same kind as
 160          * the one we are doing, there must be a programming
 161          * error.  We report it but try to continue anyway.
 162          */
 163         for (ot = ISC_LIST_HEAD(diff->tuples); ot != NULL;
 164              ot = next_ot)
 165         {
 166                 next_ot = ISC_LIST_NEXT(ot, link);
 167                 if (dns_name_equal(&ot->name, &(*tuplep)->name) &&
 168                     dns_rdata_compare(&ot->rdata, &(*tuplep)->rdata) == 0 &&
 169                     ot->ttl == (*tuplep)->ttl)
 170                 {
 171                         ISC_LIST_UNLINK(diff->tuples, ot, link);
 172                         if ((*tuplep)->op == ot->op) {
 173                                 UNEXPECTED_ERROR(__FILE__, __LINE__,
 174                                          "unexpected non-minimal diff");
 175                         } else {
 176                                 dns_difftuple_free(tuplep);
 177                         }
 178                         dns_difftuple_free(&ot);
 179                         break;
 180                 }
 181         }
 182
 183         if (*tuplep != NULL) {
 184                 ISC_LIST_APPEND(diff->tuples, *tuplep, link);
 185                 *tuplep = NULL;
 186         }
 187
 188         ENSURE(*tuplep == NULL);
 189 }
 190
 191 isc_result_t
 192 dns_diff_apply(dns_diff_t *diff, dns_db_t *db, dns_dbversion_t *ver)
 193 {
 194         dns_difftuple_t *t;
 195         dns_dbnode_t *node = NULL;
 196         isc_result_t result;
 197
 198         REQUIRE(DNS_DIFF_VALID(diff));
 199         REQUIRE(DNS_DB_VALID(db));
 200
 201         t = ISC_LIST_HEAD(diff->tuples);
 202         while (t != NULL) {
 203                 dns_name_t *name;
 204
 205                 INSIST(node == NULL);
 206                 name = &t->name;
 207                 /*
 208                  * Find the node.
 209                  * We create the node if it does not exist.
 210                  * This will cause an empty node to be created if the diff
 211                  * contains a deletion of an RR at a nonexistent name,
 212                  * but such diffs should never be created in the first
 213                  * place.
 214                  */
 215                 node = NULL;
 216                 CHECK(dns_db_findnode(db, name, ISC_TRUE, &node));
 217
 218                 while (t != NULL && dns_name_equal(&t->name, name)) {
 219                         dns_rdatatype_t type, covers;
 220                         dns_diffop_t op;
 221                         dns_rdatalist_t rdl;
 222                         dns_rdataset_t rds;
 223
 224                         op = t->op;
 225                         type = t->rdata.type;
 226                         covers = rdata_covers(&t->rdata);
 227
 228                         /*
 229                          * Collect a contiguous set of updates with
 230                          * the same operation (add/delete) and RR type
 231                          * into a single rdatalist so that the
 232                          * database rrset merging/subtraction code
 233                          * can work more efficiently than if each
 234                          * RR were merged into / subtracted from
 235                          * the database separately.
 236                          *
 237                          * This is done by linking rdata structures from the
 238                          * diff into "rdatalist".  This uses the rdata link
 239                          * field, not the diff link field, so the structure
 240                          * of the diff itself is not affected.
 241                          */
 242
 243                         rdl.type = type;
 244                         rdl.covers = covers;
 245                         rdl.rdclass = t->rdata.rdclass;
 246                         rdl.ttl = t->ttl;
 247                         ISC_LIST_INIT(rdl.rdata);
 248                         ISC_LINK_INIT(&rdl, link);
 249
 250                         while (t != NULL &&
 251                                dns_name_equal(&t->name, name) &&
 252                                t->op == op &&
 253                                t->rdata.type == type &&
 254                                rdata_covers(&t->rdata) == covers)
 255                         {
 256                                 if (t->ttl != rdl.ttl) {
 257                                         isc_log_write(DIFF_COMMON_LOGARGS,
 258                                                 ISC_LOG_WARNING,
 259                                                 "TTL differs in rdataset, "
 260                                                 "adjusting %lu -> %lu",
 261                                                 (unsigned long) t->ttl,
 262                                                 (unsigned long) rdl.ttl);
 263                                 }
 264                                 ISC_LIST_APPEND(rdl.rdata, &t->rdata, link);
 265                                 t = ISC_LIST_NEXT(t, link);
 266                         }
 267
 268                         /*
 269                          * Convert the rdatalist into a rdataset.
 270                          */
 271                         dns_rdataset_init(&rds);
 272                         CHECK(dns_rdatalist_tordataset(&rdl, &rds));
 273                         rds.trust = dns_trust_ultimate;
 274
 275                         /*
 276                          * Merge the rdataset into the database.
 277                          */
 278                         if (op == DNS_DIFFOP_ADD) {
 279                                 result = dns_db_addrdataset(db, node, ver,
 280                                                             0, &rds,
 281                                                             DNS_DBADD_MERGE|
 282                                                             DNS_DBADD_EXACT|
 283                                                             DNS_DBADD_EXACTTTL,
 284                                                             NULL);
 285                         } else if (op == DNS_DIFFOP_DEL) {
 286                                 result = dns_db_subtractrdataset(db, node, ver,
 287                                                                &rds,
 288                                                                DNS_DBSUB_EXACT,
 289                                                                NULL);
 290                         } else {
 291                                 INSIST(0);
 292                         }
 293                         if (result == DNS_R_UNCHANGED) {
 294                                 /*
 295                                  * This will not happen when executing a
 296                                  * dynamic update, because that code will
 297                                  * generate strictly minimal diffs.
 298                                  * It may happen when receiving an IXFR
 299                                  * from a server that is not as careful.
 300                                  * Issue a warning and continue.
 301                                  */
 302                                 isc_log_write(DIFF_COMMON_LOGARGS,
 303                                               ISC_LOG_WARNING,
 304                                               "update with no effect");
 305                         } else if (result == ISC_R_SUCCESS ||
 306                                    result == DNS_R_NXRRSET) {
 307                                 /*
 308                                  * OK.
 309                                  */
 310                         } else {
 311                                 CHECK(result);
 312                         }
 313                 }
 314                 dns_db_detachnode(db, &node);
 315         }
 316         return (ISC_R_SUCCESS);
 317
 318  failure:
 319         if (node != NULL)
 320                 dns_db_detachnode(db, &node);
 321         return (result);
 322 }
 323
 324 /* XXX this duplicates lots of code in dns_diff_apply(). */
 325
 326 isc_result_t
 327 dns_diff_load(dns_diff_t *diff, dns_addrdatasetfunc_t addfunc,
 328               void *add_private)
 329 {
 330         dns_difftuple_t *t;
 331         isc_result_t result;
 332
 333         REQUIRE(DNS_DIFF_VALID(diff));
 334
 335         t = ISC_LIST_HEAD(diff->tuples);
 336         while (t != NULL) {
 337                 dns_name_t *name;
 338
 339                 name = &t->name;
 340                 while (t != NULL && dns_name_equal(&t->name, name)) {
 341                         dns_rdatatype_t type, covers;
 342                         dns_diffop_t op;
 343                         dns_rdatalist_t rdl;
 344                         dns_rdataset_t rds;
 345
 346                         op = t->op;
 347                         type = t->rdata.type;
 348                         covers = rdata_covers(&t->rdata);
 349
 350                         rdl.type = type;
 351                         rdl.covers = covers;
 352                         rdl.rdclass = t->rdata.rdclass;
 353                         rdl.ttl = t->ttl;
 354                         ISC_LIST_INIT(rdl.rdata);
 355                         ISC_LINK_INIT(&rdl, link);
 356
 357                         while (t != NULL && dns_name_equal(&t->name, name) &&
 358                                t->op == op && t->rdata.type == type &&
 359                                rdata_covers(&t->rdata) == covers)
 360                         {
 361                                 ISC_LIST_APPEND(rdl.rdata, &t->rdata, link);
 362                                 t = ISC_LIST_NEXT(t, link);
 363                         }
 364
 365                         /*
 366                          * Convert the rdatalist into a rdataset.
 367                          */
 368                         dns_rdataset_init(&rds);
 369                         CHECK(dns_rdatalist_tordataset(&rdl, &rds));
 370                         rds.trust = dns_trust_ultimate;
 371
 372                         INSIST(op == DNS_DIFFOP_ADD);
 373                         result = (*addfunc)(add_private, name, &rds);
 374                         if (result == DNS_R_UNCHANGED) {
 375                                 isc_log_write(DIFF_COMMON_LOGARGS,
 376                                               ISC_LOG_WARNING,
 377                                               "update with no effect");
 378                         } else if (result == ISC_R_SUCCESS ||
 379                                    result == DNS_R_NXRRSET) {
 380                                 /*
 381                                  * OK.
 382                                  */
 383                         } else {
 384                                 CHECK(result);
 385                         }
 386                 }
 387         }
 388         result = ISC_R_SUCCESS;
 389  failure:
 390         return (result);
 391 }
 392
 393 /*
 394  * XXX uses qsort(); a merge sort would be more natural for lists,
 395  * and perhaps safer wrt thread stack overflow.
 396  */
 397 isc_result_t
 398 dns_diff_sort(dns_diff_t *diff, dns_diff_compare_func *compare) {
 399         unsigned int length = 0;
 400         unsigned int i;
 401         dns_difftuple_t **v;
 402         dns_difftuple_t *p;
 403         REQUIRE(DNS_DIFF_VALID(diff));
 404
 405         for (p = ISC_LIST_HEAD(diff->tuples);
 406              p != NULL;
 407              p = ISC_LIST_NEXT(p, link))
 408                 length++;
 409         if (length == 0)
 410                 return (ISC_R_SUCCESS);
 411         v = isc_mem_get(diff->mctx, length * sizeof(dns_difftuple_t *));
 412         if (v == NULL)
 413                 return (ISC_R_NOMEMORY);
 414         i = 0;
 415         for (i = 0; i < length; i++) {
 416                 p = ISC_LIST_HEAD(diff->tuples);
 417                 v[i] = p;
 418                 ISC_LIST_UNLINK(diff->tuples, p, link);
 419         }
 420         INSIST(ISC_LIST_HEAD(diff->tuples) == NULL);
 421         qsort(v, length, sizeof(v[0]), compare);
 422         for (i = 0; i < length; i++) {
 423                 ISC_LIST_APPEND(diff->tuples, v[i], link);
 424         }
 425         isc_mem_put(diff->mctx, v, length * sizeof(dns_difftuple_t *));
 426         return (ISC_R_SUCCESS);
 427 }
 428
 429
 430 /*
 431  * Create an rdataset containing the single RR of the given
 432  * tuple.  The caller must allocate the the rdata, rdataset and
 433  * an rdatalist structure for it to refer to.
 434  */
 435
 436 static isc_result_t
 437 diff_tuple_tordataset(dns_difftuple_t *t, dns_rdata_t *rdata,
 438                       dns_rdatalist_t *rdl, dns_rdataset_t *rds)
 439 {
 440         REQUIRE(DNS_DIFFTUPLE_VALID(t));
 441         REQUIRE(rdl != NULL);
 442         REQUIRE(rds != NULL);
 443
 444         rdl->type = t->rdata.type;
 445         rdl->rdclass = t->rdata.rdclass;
 446         rdl->ttl = t->ttl;
 447         ISC_LIST_INIT(rdl->rdata);
 448         ISC_LINK_INIT(rdl, link);
 449         dns_rdataset_init(rds);
 450         ISC_LINK_INIT(rdata, link);
 451         dns_rdata_clone(&t->rdata, rdata);
 452         ISC_LIST_APPEND(rdl->rdata, rdata, link);
 453         return (dns_rdatalist_tordataset(rdl, rds));
 454 }
 455
 456 isc_result_t
 457 dns_diff_print(dns_diff_t *diff, FILE *file) {
 458         isc_result_t result;
 459         dns_difftuple_t *t;
 460         char *mem = NULL;
 461         unsigned int size = 2048;
 462
 463         REQUIRE(DNS_DIFF_VALID(diff));
 464
 465         mem = isc_mem_get(diff->mctx, size);
 466         if (mem == NULL)
 467                 return (ISC_R_NOMEMORY);
 468
 469         for (t = ISC_LIST_HEAD(diff->tuples); t != NULL;
 470              t = ISC_LIST_NEXT(t, link))
 471         {
 472                 isc_buffer_t buf;
 473                 isc_region_t r;
 474
 475                 dns_rdatalist_t rdl;
 476                 dns_rdataset_t rds;
 477                 dns_rdata_t rd = DNS_RDATA_INIT;
 478
 479                 result = diff_tuple_tordataset(t, &rd, &rdl, &rds);
 480                 if (result != ISC_R_SUCCESS) {
 481                         UNEXPECTED_ERROR(__FILE__, __LINE__,
 482                                          "diff_tuple_tordataset failed: %s",
 483                                          dns_result_totext(result));
 484                         result =  ISC_R_UNEXPECTED;
 485                         goto cleanup;
 486                 }
 487  again:
 488                 isc_buffer_init(&buf, mem, size);
 489                 result = dns_rdataset_totext(&rds, &t->name,
 490                                              ISC_FALSE, ISC_FALSE, &buf);
 491
 492                 if (result == ISC_R_NOSPACE) {
 493                         isc_mem_put(diff->mctx, mem, size);
 494                         size += 1024;
 495                         mem = isc_mem_get(diff->mctx, size);
 496                         if (mem == NULL) {
 497                                 result = ISC_R_NOMEMORY;
 498                                 goto cleanup;
 499                         }
 500                         goto again;
 501                 }
 502
 503                 if (result != ISC_R_SUCCESS)
 504                         goto cleanup;
 505                 /*
 506                  * Get rid of final newline.
 507                  */
 508                 INSIST(buf.used >= 1 &&
 509                        ((char *) buf.base)[buf.used-1] == '\n');
 510                 buf.used--;
 511
 512                 isc_buffer_usedregion(&buf, &r);
 513                 if (file != NULL)
 514                         fprintf(file, "%s %.*s\n",
 515                                 t->op == DNS_DIFFOP_ADD ?  "add" : "del",
 516                                 (int) r.length, (char *) r.base);
 517                 else
 518                         isc_log_write(DIFF_COMMON_LOGARGS, ISC_LOG_DEBUG(7),
 519                                       "%s %.*s",
 520                                       t->op == DNS_DIFFOP_ADD ?  "add" : "del",
 521                                       (int) r.length, (char *) r.base);
 522         }
 523         result = ISC_R_SUCCESS;
 524  cleanup:
 525         if (mem != NULL)
 526                 isc_mem_put(diff->mctx, mem, size);
 527         return (result);
 528 }