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

   1 /*
   2  * Copyright (C) 2004  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 2000, 2001  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: lookup.c,v 1.9.2.3 2004/04/15 02:16:27 marka Exp $ */
  19
  20 #include <config.h>
  21
  22 #include <isc/mem.h>
  23 #include <isc/netaddr.h>
  24 #include <isc/string.h>         /* Required for HP/UX (and others?) */
  25 #include <isc/task.h>
  26 #include <isc/util.h>
  27
  28 #include <dns/db.h>
  29 #include <dns/events.h>
  30 #include <dns/lookup.h>
  31 #include <dns/rdata.h>
  32 #include <dns/rdataset.h>
  33 #include <dns/rdatastruct.h>
  34 #include <dns/resolver.h>
  35 #include <dns/result.h>
  36 #include <dns/view.h>
  37
  38 struct dns_lookup {
  39         /* Unlocked. */
  40         unsigned int            magic;
  41         isc_mem_t *             mctx;
  42         isc_mutex_t             lock;
  43         dns_rdatatype_t         type;
  44         dns_fixedname_t         name;
  45         /* Locked by lock. */
  46         unsigned int            options;
  47         isc_task_t *            task;
  48         dns_view_t *            view;
  49         dns_lookupevent_t *     event;
  50         dns_fetch_t *           fetch;
  51         unsigned int            restarts;
  52         isc_boolean_t           canceled;
  53         dns_rdataset_t          rdataset;
  54         dns_rdataset_t          sigrdataset;
  55 };
  56
  57 #define LOOKUP_MAGIC                    ISC_MAGIC('l', 'o', 'o', 'k')
  58 #define VALID_LOOKUP(l)                 ISC_MAGIC_VALID((l), LOOKUP_MAGIC)
  59
  60 #define MAX_RESTARTS 16
  61
  62 static void lookup_find(dns_lookup_t *lookup, dns_fetchevent_t *event);
  63
  64 static void
  65 fetch_done(isc_task_t *task, isc_event_t *event) {
  66         dns_lookup_t *lookup = event->ev_arg;
  67         dns_fetchevent_t *fevent;
  68
  69         UNUSED(task);
  70         REQUIRE(event->ev_type == DNS_EVENT_FETCHDONE);
  71         REQUIRE(VALID_LOOKUP(lookup));
  72         REQUIRE(lookup->task == task);
  73         fevent = (dns_fetchevent_t *)event;
  74         REQUIRE(fevent->fetch == lookup->fetch);
  75
  76         lookup_find(lookup, fevent);
  77 }
  78
  79 static inline isc_result_t
  80 start_fetch(dns_lookup_t *lookup) {
  81         isc_result_t result;
  82
  83         /*
  84          * The caller must be holding the lookup's lock.
  85          */
  86
  87         REQUIRE(lookup->fetch == NULL);
  88
  89         result = dns_resolver_createfetch(lookup->view->resolver,
  90                                           dns_fixedname_name(&lookup->name),
  91                                           lookup->type,
  92                                           NULL, NULL, NULL, 0,
  93                                           lookup->task, fetch_done, lookup,
  94                                           &lookup->rdataset,
  95                                           &lookup->sigrdataset,
  96                                           &lookup->fetch);
  97
  98         return (result);
  99 }
 100
 101 static isc_result_t
 102 build_event(dns_lookup_t *lookup) {
 103         dns_name_t *name = NULL;
 104         dns_rdataset_t *rdataset = NULL;
 105         dns_rdataset_t *sigrdataset = NULL;
 106         isc_result_t result;
 107
 108         name = isc_mem_get(lookup->mctx, sizeof(dns_name_t));
 109         if (name == NULL) {
 110                 result = ISC_R_NOMEMORY;
 111                 goto fail;
 112         }
 113         dns_name_init(name, NULL);
 114         result = dns_name_dup(dns_fixedname_name(&lookup->name),
 115                               lookup->mctx, name);
 116         if (result != ISC_R_SUCCESS)
 117                 goto fail;
 118
 119         if (dns_rdataset_isassociated(&lookup->rdataset)) {
 120                 rdataset = isc_mem_get(lookup->mctx, sizeof(dns_rdataset_t));
 121                 if (rdataset == NULL) {
 122                         result = ISC_R_NOMEMORY;
 123                         goto fail;
 124                 }
 125                 dns_rdataset_init(rdataset);
 126                 dns_rdataset_clone(&lookup->rdataset, rdataset);
 127         }
 128
 129         if (dns_rdataset_isassociated(&lookup->sigrdataset)) {
 130                 sigrdataset = isc_mem_get(lookup->mctx,
 131                                           sizeof(dns_rdataset_t));
 132                 if (sigrdataset == NULL) {
 133                         result = ISC_R_NOMEMORY;
 134                         goto fail;
 135                 }
 136                 dns_rdataset_init(sigrdataset);
 137                 dns_rdataset_clone(&lookup->sigrdataset, sigrdataset);
 138         }
 139
 140         lookup->event->name = name;
 141         lookup->event->rdataset = rdataset;
 142         lookup->event->sigrdataset = sigrdataset;
 143
 144         return (ISC_R_SUCCESS);
 145
 146  fail:
 147         if (name != NULL) {
 148                 if (dns_name_dynamic(name))
 149                         dns_name_free(name, lookup->mctx);
 150                 isc_mem_put(lookup->mctx, name, sizeof(dns_name_t));
 151         }
 152         if (rdataset != NULL) {
 153                 if (dns_rdataset_isassociated(rdataset))
 154                         dns_rdataset_disassociate(rdataset);
 155                 isc_mem_put(lookup->mctx, rdataset, sizeof(dns_rdataset_t));
 156         }
 157         if (sigrdataset != NULL) {
 158                 if (dns_rdataset_isassociated(sigrdataset))
 159                         dns_rdataset_disassociate(sigrdataset);
 160                 isc_mem_put(lookup->mctx, sigrdataset, sizeof(dns_rdataset_t));
 161         }
 162         return (result);
 163 }
 164
 165 static isc_result_t
 166 view_find(dns_lookup_t *lookup, dns_name_t *foundname) {
 167         isc_result_t result;
 168         dns_name_t *name = dns_fixedname_name(&lookup->name);
 169         dns_rdatatype_t type;
 170
 171         if (lookup->type == dns_rdatatype_sig)
 172                 type = dns_rdatatype_any;
 173         else
 174                 type = lookup->type;
 175
 176         result = dns_view_find(lookup->view, name, type, 0, 0, ISC_FALSE,
 177                                &lookup->event->db, &lookup->event->node,
 178                                foundname, &lookup->rdataset,
 179                                &lookup->sigrdataset);
 180         return (result);
 181 }
 182
 183 static void
 184 lookup_find(dns_lookup_t *lookup, dns_fetchevent_t *event) {
 185         isc_result_t result;
 186         isc_boolean_t want_restart;
 187         isc_boolean_t send_event = ISC_FALSE;
 188         dns_name_t *name, *fname, *prefix;
 189         dns_fixedname_t foundname, fixed;
 190         dns_rdata_t rdata = DNS_RDATA_INIT;
 191         unsigned int nlabels, nbits;
 192         int order;
 193         dns_namereln_t namereln;
 194         dns_rdata_cname_t cname;
 195         dns_rdata_dname_t dname;
 196
 197         REQUIRE(VALID_LOOKUP(lookup));
 198
 199         LOCK(&lookup->lock);
 200
 201         result = ISC_R_SUCCESS;
 202         name = dns_fixedname_name(&lookup->name);
 203
 204         do {
 205                 lookup->restarts++;
 206                 want_restart = ISC_FALSE;
 207
 208                 if (event == NULL && !lookup->canceled) {
 209                         dns_fixedname_init(&foundname);
 210                         fname = dns_fixedname_name(&foundname);
 211                         INSIST(!dns_rdataset_isassociated(&lookup->rdataset));
 212                         INSIST(!dns_rdataset_isassociated
 213                                                 (&lookup->sigrdataset));
 214                         result = view_find(lookup, fname);
 215                         if (result == ISC_R_NOTFOUND) {
 216                                 /*
 217                                  * We don't know anything about the name.
 218                                  * Launch a fetch.
 219                                  */
 220                                 if  (lookup->event->node != NULL) {
 221                                         INSIST(lookup->event->db != NULL);
 222                                         dns_db_detachnode(lookup->event->db,
 223                                                          &lookup->event->node);
 224                                 }
 225                                 if (lookup->event->db != NULL)
 226                                         dns_db_detach(&lookup->event->db);
 227                                 result = start_fetch(lookup);
 228                                 if (result != ISC_R_SUCCESS)
 229                                         send_event = ISC_TRUE;
 230                                 goto done;
 231                         }
 232                 } else {
 233                         result = event->result;
 234                         fname = dns_fixedname_name(&event->foundname);
 235                         dns_resolver_destroyfetch(&lookup->fetch);
 236                         INSIST(event->rdataset == &lookup->rdataset);
 237                         INSIST(event->sigrdataset == &lookup->sigrdataset);
 238                 }
 239
 240                 /*
 241                  * If we've been canceled, forget about the result.
 242                  */
 243                 if (lookup->canceled)
 244                         result = ISC_R_CANCELED;
 245
 246                 switch (result) {
 247                 case ISC_R_SUCCESS:
 248                         result = build_event(lookup);
 249                         send_event = ISC_TRUE;
 250                         if (event == NULL)
 251                                 break;
 252                         if (event->db != NULL)
 253                                 dns_db_attach(event->db, &lookup->event->db);
 254                         if (event->node != NULL)
 255                                 dns_db_attachnode(lookup->event->db,
 256                                                   event->node,
 257                                                   &lookup->event->node);
 258                         break;
 259                 case DNS_R_CNAME:
 260                         /*
 261                          * Copy the CNAME's target into the lookup's
 262                          * query name and start over.
 263                          */
 264                         result = dns_rdataset_first(&lookup->rdataset);
 265                         if (result != ISC_R_SUCCESS)
 266                                 break;
 267                         dns_rdataset_current(&lookup->rdataset, &rdata);
 268                         result = dns_rdata_tostruct(&rdata, &cname, NULL);
 269                         dns_rdata_reset(&rdata);
 270                         if (result != ISC_R_SUCCESS)
 271                                 break;
 272                         result = dns_name_copy(&cname.cname, name, NULL);
 273                         dns_rdata_freestruct(&cname);
 274                         if (result == ISC_R_SUCCESS)
 275                                 want_restart = ISC_TRUE;
 276                         break;
 277                 case DNS_R_DNAME:
 278                         namereln = dns_name_fullcompare(name, fname, &order,
 279                                                         &nlabels, &nbits);
 280                         INSIST(namereln == dns_namereln_subdomain);
 281                         /*
 282                          * Get the target name of the DNAME.
 283                          */
 284                         result = dns_rdataset_first(&lookup->rdataset);
 285                         if (result != ISC_R_SUCCESS)
 286                                 break;
 287                         dns_rdataset_current(&lookup->rdataset, &rdata);
 288                         result = dns_rdata_tostruct(&rdata, &dname, NULL);
 289                         dns_rdata_reset(&rdata);
 290                         if (result != ISC_R_SUCCESS)
 291                                 break;
 292                         /*
 293                          * Construct the new query name and start over.
 294                          */
 295                         dns_fixedname_init(&fixed);
 296                         prefix = dns_fixedname_name(&fixed);
 297                         result = dns_name_split(name, nlabels, nbits, prefix,
 298                                                 NULL);
 299                         if (result != ISC_R_SUCCESS) {
 300                                 dns_rdata_freestruct(&dname);
 301                                 break;
 302                         }
 303                         result = dns_name_concatenate(prefix, &dname.dname,
 304                                                       name, NULL);
 305                         dns_rdata_freestruct(&dname);
 306                         if (result == ISC_R_SUCCESS)
 307                                 want_restart = ISC_TRUE;
 308                         break;
 309                 default:
 310                         send_event = ISC_TRUE;
 311                 }
 312
 313                 if (dns_rdataset_isassociated(&lookup->rdataset))
 314                         dns_rdataset_disassociate(&lookup->rdataset);
 315                 if (dns_rdataset_isassociated(&lookup->sigrdataset))
 316                         dns_rdataset_disassociate(&lookup->sigrdataset);
 317
 318         done:
 319                 if (event != NULL) {
 320                         if (event->node != NULL)
 321                                 dns_db_detachnode(event->db, &event->node);
 322                         if (event->db != NULL)
 323                                 dns_db_detach(&event->db);
 324                         isc_event_free(ISC_EVENT_PTR(&event));
 325                 }
 326
 327                 /*
 328                  * Limit the number of restarts.
 329                  */
 330                 if (want_restart && lookup->restarts == MAX_RESTARTS) {
 331                         want_restart = ISC_FALSE;
 332                         result = ISC_R_QUOTA;
 333                         send_event = ISC_TRUE;
 334                 }
 335
 336         } while (want_restart);
 337
 338         if (send_event) {
 339                 lookup->event->result = result;
 340                 lookup->event->ev_sender = lookup;
 341                 isc_task_sendanddetach(&lookup->task,
 342                                        (isc_event_t **)&lookup->event);
 343                 dns_view_detach(&lookup->view);
 344         }
 345
 346         UNLOCK(&lookup->lock);
 347 }
 348
 349 static void
 350 levent_destroy(isc_event_t *event) {
 351         dns_lookupevent_t *levent;
 352         isc_mem_t *mctx;
 353
 354         REQUIRE(event->ev_type == DNS_EVENT_LOOKUPDONE);
 355         mctx = event->ev_destroy_arg;
 356         levent = (dns_lookupevent_t *)event;
 357
 358         if (levent->name != NULL) {
 359                 if (dns_name_dynamic(levent->name))
 360                         dns_name_free(levent->name, mctx);
 361                 isc_mem_put(mctx, levent->name, sizeof(dns_name_t));
 362         }
 363         if (levent->rdataset != NULL) {
 364                 dns_rdataset_disassociate(levent->rdataset);
 365                 isc_mem_put(mctx, levent->rdataset, sizeof(dns_rdataset_t));
 366         }
 367         if (levent->sigrdataset != NULL) {
 368                 dns_rdataset_disassociate(levent->sigrdataset);
 369                 isc_mem_put(mctx, levent->sigrdataset, sizeof(dns_rdataset_t));
 370         }
 371         if (levent->node != NULL)
 372                 dns_db_detachnode(levent->db, &levent->node);
 373         if (levent->db != NULL)
 374                 dns_db_detach(&levent->db);
 375         isc_mem_put(mctx, event, event->ev_size);
 376 }
 377
 378
 379 isc_result_t
 380 dns_lookup_create(isc_mem_t *mctx, dns_name_t *name, dns_rdatatype_t type,
 381                   dns_view_t *view, unsigned int options, isc_task_t *task,
 382                   isc_taskaction_t action, void *arg, dns_lookup_t **lookupp)
 383 {
 384         isc_result_t result;
 385         dns_lookup_t *lookup;
 386         isc_event_t *ievent;
 387
 388         lookup = isc_mem_get(mctx, sizeof *lookup);
 389         if (lookup == NULL)
 390                 return (ISC_R_NOMEMORY);
 391         lookup->mctx = mctx;
 392         lookup->options = options;
 393
 394         ievent = isc_event_allocate(mctx, lookup, DNS_EVENT_LOOKUPDONE,
 395                                     action, arg, sizeof *lookup->event);
 396         if (ievent == NULL) {
 397                 result = ISC_R_NOMEMORY;
 398                 goto cleanup_lookup;
 399         }
 400         lookup->event = (dns_lookupevent_t *)ievent;
 401         lookup->event->ev_destroy = levent_destroy;
 402         lookup->event->ev_destroy_arg = mctx;
 403         lookup->event->result = ISC_R_FAILURE;
 404         lookup->event->name = NULL;
 405         lookup->event->rdataset = NULL;
 406         lookup->event->sigrdataset = NULL;
 407         lookup->event->db = NULL;
 408         lookup->event->node = NULL;
 409
 410         lookup->task = NULL;
 411         isc_task_attach(task, &lookup->task);
 412
 413         result = isc_mutex_init(&lookup->lock);
 414         if (result != ISC_R_SUCCESS)
 415                 goto cleanup_event;
 416
 417         dns_fixedname_init(&lookup->name);
 418
 419         result = dns_name_copy(name, dns_fixedname_name(&lookup->name), NULL);
 420         if (result != ISC_R_SUCCESS)
 421                 goto cleanup_lock;
 422
 423         lookup->type = type;
 424         lookup->view = NULL;
 425         dns_view_attach(view, &lookup->view);
 426         lookup->fetch = NULL;
 427         lookup->restarts = 0;
 428         lookup->canceled = ISC_FALSE;
 429         dns_rdataset_init(&lookup->rdataset);
 430         dns_rdataset_init(&lookup->sigrdataset);
 431         lookup->magic = LOOKUP_MAGIC;
 432
 433         *lookupp = lookup;
 434
 435         lookup_find(lookup, NULL);
 436
 437         return (ISC_R_SUCCESS);
 438
 439  cleanup_lock:
 440         DESTROYLOCK(&lookup->lock);
 441
 442  cleanup_event:
 443         ievent = (isc_event_t *)lookup->event;
 444         isc_event_free(&ievent);
 445         lookup->event = NULL;
 446
 447         isc_task_detach(&lookup->task);
 448
 449  cleanup_lookup:
 450         isc_mem_put(mctx, lookup, sizeof *lookup);
 451
 452         return (result);
 453 }
 454
 455 void
 456 dns_lookup_cancel(dns_lookup_t *lookup) {
 457         REQUIRE(VALID_LOOKUP(lookup));
 458
 459         LOCK(&lookup->lock);
 460
 461         if (!lookup->canceled) {
 462                 lookup->canceled = ISC_TRUE;
 463                 if (lookup->fetch != NULL) {
 464                         INSIST(lookup->view != NULL);
 465                         dns_resolver_cancelfetch(lookup->fetch);
 466                 }
 467         }
 468
 469         UNLOCK(&lookup->lock);
 470 }
 471
 472 void
 473 dns_lookup_destroy(dns_lookup_t **lookupp) {
 474         dns_lookup_t *lookup;
 475
 476         REQUIRE(lookupp != NULL);
 477         lookup = *lookupp;
 478         REQUIRE(VALID_LOOKUP(lookup));
 479         REQUIRE(lookup->event == NULL);
 480         REQUIRE(lookup->task == NULL);
 481         REQUIRE(lookup->view == NULL);
 482         if (dns_rdataset_isassociated(&lookup->rdataset))
 483                 dns_rdataset_disassociate(&lookup->rdataset);
 484         if (dns_rdataset_isassociated(&lookup->sigrdataset))
 485                 dns_rdataset_disassociate(&lookup->sigrdataset);
 486
 487         DESTROYLOCK(&lookup->lock);
 488         lookup->magic = 0;
 489         isc_mem_put(lookup->mctx, lookup, sizeof *lookup);
 490
 491         *lookupp = NULL;
 492 }