contrib/bind-9.3/lib/dns/lookup.c

   1 /*
   2  * Copyright (C) 2004, 2006  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 2000, 2001, 2003  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 1.9.12.7 2006/01/04 23:50:20 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         return (result);
 158 }
 159
 160 static isc_result_t
 161 view_find(dns_lookup_t *lookup, dns_name_t *foundname) {
 162         isc_result_t result;
 163         dns_name_t *name = dns_fixedname_name(&lookup->name);
 164         dns_rdatatype_t type;
 165
 166         if (lookup->type == dns_rdatatype_rrsig)
 167                 type = dns_rdatatype_any;
 168         else
 169                 type = lookup->type;
 170
 171         result = dns_view_find(lookup->view, name, type, 0, 0, ISC_FALSE,
 172                                &lookup->event->db, &lookup->event->node,
 173                                foundname, &lookup->rdataset,
 174                                &lookup->sigrdataset);
 175         return (result);
 176 }
 177
 178 static void
 179 lookup_find(dns_lookup_t *lookup, dns_fetchevent_t *event) {
 180         isc_result_t result;
 181         isc_boolean_t want_restart;
 182         isc_boolean_t send_event = ISC_FALSE;
 183         dns_name_t *name, *fname, *prefix;
 184         dns_fixedname_t foundname, fixed;
 185         dns_rdata_t rdata = DNS_RDATA_INIT;
 186         unsigned int nlabels;
 187         int order;
 188         dns_namereln_t namereln;
 189         dns_rdata_cname_t cname;
 190         dns_rdata_dname_t dname;
 191
 192         REQUIRE(VALID_LOOKUP(lookup));
 193
 194         LOCK(&lookup->lock);
 195
 196         result = ISC_R_SUCCESS;
 197         name = dns_fixedname_name(&lookup->name);
 198
 199         do {
 200                 lookup->restarts++;
 201                 want_restart = ISC_FALSE;
 202
 203                 if (event == NULL && !lookup->canceled) {
 204                         dns_fixedname_init(&foundname);
 205                         fname = dns_fixedname_name(&foundname);
 206                         INSIST(!dns_rdataset_isassociated(&lookup->rdataset));
 207                         INSIST(!dns_rdataset_isassociated
 208                                                 (&lookup->sigrdataset));
 209                         result = view_find(lookup, fname);
 210                         if (result == ISC_R_NOTFOUND) {
 211                                 /*
 212                                  * We don't know anything about the name.
 213                                  * Launch a fetch.
 214                                  */
 215                                 if  (lookup->event->node != NULL) {
 216                                         INSIST(lookup->event->db != NULL);
 217                                         dns_db_detachnode(lookup->event->db,
 218                                                          &lookup->event->node);
 219                                 }
 220                                 if (lookup->event->db != NULL)
 221                                         dns_db_detach(&lookup->event->db);
 222                                 result = start_fetch(lookup);
 223                                 if (result != ISC_R_SUCCESS)
 224                                         send_event = ISC_TRUE;
 225                                 goto done;
 226                         }
 227                 } else if (event != NULL) {
 228                         result = event->result;
 229                         fname = dns_fixedname_name(&event->foundname);
 230                         dns_resolver_destroyfetch(&lookup->fetch);
 231                         INSIST(event->rdataset == &lookup->rdataset);
 232                         INSIST(event->sigrdataset == &lookup->sigrdataset);
 233                 } else
 234                         fname = NULL;   /* Silence compiler warning. */
 235
 236                 /*
 237                  * If we've been canceled, forget about the result.
 238                  */
 239                 if (lookup->canceled)
 240                         result = ISC_R_CANCELED;
 241
 242                 switch (result) {
 243                 case ISC_R_SUCCESS:
 244                         result = build_event(lookup);
 245                         send_event = ISC_TRUE;
 246                         if (event == NULL)
 247                                 break;
 248                         if (event->db != NULL)
 249                                 dns_db_attach(event->db, &lookup->event->db);
 250                         if (event->node != NULL)
 251                                 dns_db_attachnode(lookup->event->db,
 252                                                   event->node,
 253                                                   &lookup->event->node);
 254                         break;
 255                 case DNS_R_CNAME:
 256                         /*
 257                          * Copy the CNAME's target into the lookup's
 258                          * query name and start over.
 259                          */
 260                         result = dns_rdataset_first(&lookup->rdataset);
 261                         if (result != ISC_R_SUCCESS)
 262                                 break;
 263                         dns_rdataset_current(&lookup->rdataset, &rdata);
 264                         result = dns_rdata_tostruct(&rdata, &cname, NULL);
 265                         dns_rdata_reset(&rdata);
 266                         if (result != ISC_R_SUCCESS)
 267                                 break;
 268                         result = dns_name_copy(&cname.cname, name, NULL);
 269                         dns_rdata_freestruct(&cname);
 270                         if (result == ISC_R_SUCCESS)
 271                                 want_restart = ISC_TRUE;
 272                         break;
 273                 case DNS_R_DNAME:
 274                         namereln = dns_name_fullcompare(name, fname, &order,
 275                                                         &nlabels);
 276                         INSIST(namereln == dns_namereln_subdomain);
 277                         /*
 278                          * Get the target name of the DNAME.
 279                          */
 280                         result = dns_rdataset_first(&lookup->rdataset);
 281                         if (result != ISC_R_SUCCESS)
 282                                 break;
 283                         dns_rdataset_current(&lookup->rdataset, &rdata);
 284                         result = dns_rdata_tostruct(&rdata, &dname, NULL);
 285                         dns_rdata_reset(&rdata);
 286                         if (result != ISC_R_SUCCESS)
 287                                 break;
 288                         /*
 289                          * Construct the new query name and start over.
 290                          */
 291                         dns_fixedname_init(&fixed);
 292                         prefix = dns_fixedname_name(&fixed);
 293                         dns_name_split(name, nlabels, prefix, NULL);
 294                         result = dns_name_concatenate(prefix, &dname.dname,
 295                                                       name, NULL);
 296                         dns_rdata_freestruct(&dname);
 297                         if (result == ISC_R_SUCCESS)
 298                                 want_restart = ISC_TRUE;
 299                         break;
 300                 default:
 301                         send_event = ISC_TRUE;
 302                 }
 303
 304                 if (dns_rdataset_isassociated(&lookup->rdataset))
 305                         dns_rdataset_disassociate(&lookup->rdataset);
 306                 if (dns_rdataset_isassociated(&lookup->sigrdataset))
 307                         dns_rdataset_disassociate(&lookup->sigrdataset);
 308
 309         done:
 310                 if (event != NULL) {
 311                         if (event->node != NULL)
 312                                 dns_db_detachnode(event->db, &event->node);
 313                         if (event->db != NULL)
 314                                 dns_db_detach(&event->db);
 315                         isc_event_free(ISC_EVENT_PTR(&event));
 316                 }
 317
 318                 /*
 319                  * Limit the number of restarts.
 320                  */
 321                 if (want_restart && lookup->restarts == MAX_RESTARTS) {
 322                         want_restart = ISC_FALSE;
 323                         result = ISC_R_QUOTA;
 324                         send_event = ISC_TRUE;
 325                 }
 326
 327         } while (want_restart);
 328
 329         if (send_event) {
 330                 lookup->event->result = result;
 331                 lookup->event->ev_sender = lookup;
 332                 isc_task_sendanddetach(&lookup->task,
 333                                        (isc_event_t **)&lookup->event);
 334                 dns_view_detach(&lookup->view);
 335         }
 336
 337         UNLOCK(&lookup->lock);
 338 }
 339
 340 static void
 341 levent_destroy(isc_event_t *event) {
 342         dns_lookupevent_t *levent;
 343         isc_mem_t *mctx;
 344
 345         REQUIRE(event->ev_type == DNS_EVENT_LOOKUPDONE);
 346         mctx = event->ev_destroy_arg;
 347         levent = (dns_lookupevent_t *)event;
 348
 349         if (levent->name != NULL) {
 350                 if (dns_name_dynamic(levent->name))
 351                         dns_name_free(levent->name, mctx);
 352                 isc_mem_put(mctx, levent->name, sizeof(dns_name_t));
 353         }
 354         if (levent->rdataset != NULL) {
 355                 dns_rdataset_disassociate(levent->rdataset);
 356                 isc_mem_put(mctx, levent->rdataset, sizeof(dns_rdataset_t));
 357         }
 358         if (levent->sigrdataset != NULL) {
 359                 dns_rdataset_disassociate(levent->sigrdataset);
 360                 isc_mem_put(mctx, levent->sigrdataset, sizeof(dns_rdataset_t));
 361         }
 362         if (levent->node != NULL)
 363                 dns_db_detachnode(levent->db, &levent->node);
 364         if (levent->db != NULL)
 365                 dns_db_detach(&levent->db);
 366         isc_mem_put(mctx, event, event->ev_size);
 367 }
 368
 369
 370 isc_result_t
 371 dns_lookup_create(isc_mem_t *mctx, dns_name_t *name, dns_rdatatype_t type,
 372                   dns_view_t *view, unsigned int options, isc_task_t *task,
 373                   isc_taskaction_t action, void *arg, dns_lookup_t **lookupp)
 374 {
 375         isc_result_t result;
 376         dns_lookup_t *lookup;
 377         isc_event_t *ievent;
 378
 379         lookup = isc_mem_get(mctx, sizeof(*lookup));
 380         if (lookup == NULL)
 381                 return (ISC_R_NOMEMORY);
 382         lookup->mctx = mctx;
 383         lookup->options = options;
 384
 385         ievent = isc_event_allocate(mctx, lookup, DNS_EVENT_LOOKUPDONE,
 386                                     action, arg, sizeof(*lookup->event));
 387         if (ievent == NULL) {
 388                 result = ISC_R_NOMEMORY;
 389                 goto cleanup_lookup;
 390         }
 391         lookup->event = (dns_lookupevent_t *)ievent;
 392         lookup->event->ev_destroy = levent_destroy;
 393         lookup->event->ev_destroy_arg = mctx;
 394         lookup->event->result = ISC_R_FAILURE;
 395         lookup->event->name = NULL;
 396         lookup->event->rdataset = NULL;
 397         lookup->event->sigrdataset = NULL;
 398         lookup->event->db = NULL;
 399         lookup->event->node = NULL;
 400
 401         lookup->task = NULL;
 402         isc_task_attach(task, &lookup->task);
 403
 404         result = isc_mutex_init(&lookup->lock);
 405         if (result != ISC_R_SUCCESS)
 406                 goto cleanup_event;
 407
 408         dns_fixedname_init(&lookup->name);
 409
 410         result = dns_name_copy(name, dns_fixedname_name(&lookup->name), NULL);
 411         if (result != ISC_R_SUCCESS)
 412                 goto cleanup_lock;
 413
 414         lookup->type = type;
 415         lookup->view = NULL;
 416         dns_view_attach(view, &lookup->view);
 417         lookup->fetch = NULL;
 418         lookup->restarts = 0;
 419         lookup->canceled = ISC_FALSE;
 420         dns_rdataset_init(&lookup->rdataset);
 421         dns_rdataset_init(&lookup->sigrdataset);
 422         lookup->magic = LOOKUP_MAGIC;
 423
 424         *lookupp = lookup;
 425
 426         lookup_find(lookup, NULL);
 427
 428         return (ISC_R_SUCCESS);
 429
 430  cleanup_lock:
 431         DESTROYLOCK(&lookup->lock);
 432
 433  cleanup_event:
 434         ievent = (isc_event_t *)lookup->event;
 435         isc_event_free(&ievent);
 436         lookup->event = NULL;
 437
 438         isc_task_detach(&lookup->task);
 439
 440  cleanup_lookup:
 441         isc_mem_put(mctx, lookup, sizeof(*lookup));
 442
 443         return (result);
 444 }
 445
 446 void
 447 dns_lookup_cancel(dns_lookup_t *lookup) {
 448         REQUIRE(VALID_LOOKUP(lookup));
 449
 450         LOCK(&lookup->lock);
 451
 452         if (!lookup->canceled) {
 453                 lookup->canceled = ISC_TRUE;
 454                 if (lookup->fetch != NULL) {
 455                         INSIST(lookup->view != NULL);
 456                         dns_resolver_cancelfetch(lookup->fetch);
 457                 }
 458         }
 459
 460         UNLOCK(&lookup->lock);
 461 }
 462
 463 void
 464 dns_lookup_destroy(dns_lookup_t **lookupp) {
 465         dns_lookup_t *lookup;
 466
 467         REQUIRE(lookupp != NULL);
 468         lookup = *lookupp;
 469         REQUIRE(VALID_LOOKUP(lookup));
 470         REQUIRE(lookup->event == NULL);
 471         REQUIRE(lookup->task == NULL);
 472         REQUIRE(lookup->view == NULL);
 473         if (dns_rdataset_isassociated(&lookup->rdataset))
 474                 dns_rdataset_disassociate(&lookup->rdataset);
 475         if (dns_rdataset_isassociated(&lookup->sigrdataset))
 476                 dns_rdataset_disassociate(&lookup->sigrdataset);
 477
 478         DESTROYLOCK(&lookup->lock);
 479         lookup->magic = 0;
 480         isc_mem_put(lookup->mctx, lookup, sizeof(*lookup));
 481
 482         *lookupp = NULL;
 483 }