contrib/bind-9.5.2/lib/dns/dlz.c

   1 /*
   2  * Portions Copyright (C) 2005, 2007, 2009  Internet Systems Consortium, Inc. ("ISC")
   3  * Portions Copyright (C) 1999-2001  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and/or distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
  10  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  11  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  12  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  13  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  14  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  15  * PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 /*
  19  * Copyright (C) 2002 Stichting NLnet, Netherlands, stichting@nlnet.nl.
  20  *
  21  * Permission to use, copy, modify, and distribute this software for any
  22  * purpose with or without fee is hereby granted, provided that the
  23  * above copyright notice and this permission notice appear in all
  24  * copies.
  25  *
  26  * THE SOFTWARE IS PROVIDED "AS IS" AND STICHTING NLNET
  27  * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
  29  * STICHTING NLNET BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
  30  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
  31  * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  32  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE
  33  * USE OR PERFORMANCE OF THIS SOFTWARE.
  34  *
  35  * The development of Dynamically Loadable Zones (DLZ) for Bind 9 was
  36  * conceived and contributed by Rob Butler.
  37  *
  38  * Permission to use, copy, modify, and distribute this software for any
  39  * purpose with or without fee is hereby granted, provided that the
  40  * above copyright notice and this permission notice appear in all
  41  * copies.
  42  *
  43  * THE SOFTWARE IS PROVIDED "AS IS" AND ROB BUTLER
  44  * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
  45  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
  46  * ROB BUTLER BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
  47  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
  48  * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  49  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE
  50  * USE OR PERFORMANCE OF THIS SOFTWARE.
  51  */
  52
  53 /* $Id: dlz.c,v 1.5.128.2 2009/01/19 23:47:02 tbox Exp $ */
  54
  55 /*! \file */
  56
  57 /***
  58  *** Imports
  59  ***/
  60
  61 #include <config.h>
  62
  63 #include <dns/fixedname.h>
  64 #include <dns/log.h>
  65 #include <dns/master.h>
  66 #include <dns/dlz.h>
  67
  68
  69 #include <isc/buffer.h>
  70 #include <isc/magic.h>
  71 #include <isc/mem.h>
  72 #include <isc/once.h>
  73 #include <isc/rwlock.h>
  74 #include <isc/string.h>
  75 #include <isc/util.h>
  76
  77 /***
  78  *** Supported DLZ DB Implementations Registry
  79  ***/
  80
  81 static ISC_LIST(dns_dlzimplementation_t) dlz_implementations;
  82 static isc_rwlock_t dlz_implock;
  83 static isc_once_t once = ISC_ONCE_INIT;
  84
  85 static void
  86 dlz_initialize(void) {
  87         RUNTIME_CHECK(isc_rwlock_init(&dlz_implock, 0, 0) == ISC_R_SUCCESS);
  88         ISC_LIST_INIT(dlz_implementations);
  89 }
  90
  91 /*%
  92  * Searches the dlz_implementations list for a driver matching name.
  93  */
  94 static inline dns_dlzimplementation_t *
  95 dlz_impfind(const char *name) {
  96         dns_dlzimplementation_t *imp;
  97
  98         for (imp = ISC_LIST_HEAD(dlz_implementations);
  99              imp != NULL;
 100              imp = ISC_LIST_NEXT(imp, link))
 101                 if (strcasecmp(name, imp->name) == 0)
 102                         return (imp);
 103         return (NULL);
 104 }
 105
 106 /***
 107  *** Basic DLZ Methods
 108  ***/
 109
 110 isc_result_t
 111 dns_dlzallowzonexfr(dns_view_t *view, dns_name_t *name,
 112                     isc_sockaddr_t *clientaddr, dns_db_t **dbp)
 113 {
 114         isc_result_t result;
 115         dns_dlzallowzonexfr_t allowzonexfr;
 116         dns_dlzdb_t *dlzdatabase;
 117
 118         /*
 119          * Performs checks to make sure data is as we expect it to be.
 120          */
 121         REQUIRE(DNS_DLZ_VALID(view->dlzdatabase));
 122         REQUIRE(name != NULL);
 123         REQUIRE(dbp != NULL && *dbp == NULL);
 124
 125         /* ask driver if the zone is supported */
 126         dlzdatabase = view->dlzdatabase;
 127         allowzonexfr = dlzdatabase->implementation->methods->allowzonexfr;
 128         result = (*allowzonexfr)(dlzdatabase->implementation->driverarg,
 129                                  dlzdatabase->dbdata, dlzdatabase->mctx,
 130                                  view->rdclass, name, clientaddr, dbp);
 131
 132         if (result == ISC_R_NOTIMPLEMENTED)
 133                 return (ISC_R_NOTFOUND);
 134         return (result);
 135 }
 136
 137 isc_result_t
 138 dns_dlzcreate(isc_mem_t *mctx, const char *dlzname, const char *drivername,
 139               unsigned int argc, char *argv[], dns_dlzdb_t **dbp)
 140 {
 141         dns_dlzimplementation_t *impinfo;
 142         isc_result_t result;
 143
 144         /*
 145          * initialize the dlz_implementations list, this is guaranteed
 146          * to only really happen once.
 147          */
 148         RUNTIME_CHECK(isc_once_do(&once, dlz_initialize) == ISC_R_SUCCESS);
 149
 150         /*
 151          * Performs checks to make sure data is as we expect it to be.
 152          */
 153         REQUIRE(dbp != NULL && *dbp == NULL);
 154         REQUIRE(dlzname != NULL);
 155         REQUIRE(drivername != NULL);
 156         REQUIRE(mctx != NULL);
 157
 158         /* write log message */
 159         isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
 160                       DNS_LOGMODULE_DLZ, ISC_LOG_INFO,
 161                       "Loading '%s' using driver %s", dlzname, drivername);
 162
 163         /* lock the dlz_implementations list so we can search it. */
 164         RWLOCK(&dlz_implock, isc_rwlocktype_read);
 165
 166         /* search for the driver implementation  */
 167         impinfo = dlz_impfind(drivername);
 168         if (impinfo == NULL) {
 169                 RWUNLOCK(&dlz_implock, isc_rwlocktype_read);
 170
 171                 isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
 172                               DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
 173                               "unsupported DLZ database driver '%s'."
 174                               "  %s not loaded.",
 175                               drivername, dlzname);
 176
 177                 return (ISC_R_NOTFOUND);
 178         }
 179
 180         /* Allocate memory to hold the DLZ database driver */
 181         (*dbp) = isc_mem_get(mctx, sizeof(dns_dlzdb_t));
 182         if ((*dbp) == NULL) {
 183                 RWUNLOCK(&dlz_implock, isc_rwlocktype_read);
 184                 return (ISC_R_NOMEMORY);
 185         }
 186
 187         /* Make sure memory region is set to all 0's */
 188         memset((*dbp), 0, sizeof(dns_dlzdb_t));
 189
 190         (*dbp)->implementation = impinfo;
 191
 192         /* Create a new database using implementation 'drivername'. */
 193         result = ((impinfo->methods->create)(mctx, dlzname, argc, argv,
 194                                              impinfo->driverarg,
 195                                              &(*dbp)->dbdata));
 196
 197         /* mark the DLZ driver as valid */
 198         if (result == ISC_R_SUCCESS) {
 199                 RWUNLOCK(&dlz_implock, isc_rwlocktype_read);
 200                 (*dbp)->magic = DNS_DLZ_MAGIC;
 201                 isc_mem_attach(mctx, &(*dbp)->mctx);
 202                 isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
 203                               DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),
 204                               "DLZ driver loaded successfully.");
 205                 return (ISC_R_SUCCESS);
 206         } else {
 207                 isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
 208                               DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
 209                               "DLZ driver failed to load.");
 210         }
 211
 212         /* impinfo->methods->create failed. */
 213         RWUNLOCK(&dlz_implock, isc_rwlocktype_read);
 214         isc_mem_put(mctx, (*dbp), sizeof(dns_dlzdb_t));
 215         return (result);
 216 }
 217
 218 void
 219 dns_dlzdestroy(dns_dlzdb_t **dbp) {
 220         isc_mem_t *mctx;
 221         dns_dlzdestroy_t destroy;
 222
 223         /* Write debugging message to log */
 224         isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
 225                       DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),
 226                       "Unloading DLZ driver.");
 227
 228         /*
 229          * Perform checks to make sure data is as we expect it to be.
 230          */
 231         REQUIRE(dbp != NULL && DNS_DLZ_VALID(*dbp));
 232
 233         /* call the drivers destroy method */
 234         if ((*dbp) != NULL) {
 235                 mctx = (*dbp)->mctx;
 236                 destroy = (*dbp)->implementation->methods->destroy;
 237                 (*destroy)((*dbp)->implementation->driverarg,(*dbp)->dbdata);
 238                 /* return memory */
 239                 isc_mem_put(mctx, (*dbp), sizeof(dns_dlzdb_t));
 240                 isc_mem_detach(&mctx);
 241         }
 242
 243         *dbp = NULL;
 244 }
 245
 246
 247 isc_result_t
 248 dns_dlzfindzone(dns_view_t *view, dns_name_t *name, unsigned int minlabels,
 249                 dns_db_t **dbp)
 250 {
 251         dns_fixedname_t fname;
 252         dns_name_t *zonename;
 253         unsigned int namelabels;
 254         unsigned int i;
 255         isc_result_t result;
 256         dns_dlzfindzone_t findzone;
 257         dns_dlzdb_t *dlzdatabase;
 258
 259         /*
 260          * Performs checks to make sure data is as we expect it to be.
 261          */
 262         REQUIRE(DNS_DLZ_VALID(view->dlzdatabase));
 263         REQUIRE(name != NULL);
 264         REQUIRE(dbp != NULL && *dbp == NULL);
 265
 266         /* setup a "fixed" dns name */
 267         dns_fixedname_init(&fname);
 268         zonename = dns_fixedname_name(&fname);
 269
 270         /* count the number of labels in the name */
 271         namelabels = dns_name_countlabels(name);
 272
 273         /*
 274          * loop through starting with the longest domain name and
 275          * trying shorter names portions of the name until we find a
 276          * match, have an error, or are below the 'minlabels'
 277          * threshold.  minlabels is 0, if the standard database didn't
 278          * have a zone name match.  Otherwise minlabels is the number
 279          * of labels in that name.  We need to beat that for a
 280          * "better" match for the DLZ database to be authoritative
 281          * instead of the standard database.
 282          */
 283         for (i = namelabels; i > minlabels && i > 1; i--) {
 284                 if (i == namelabels) {
 285                         result = dns_name_copy(name, zonename, NULL);
 286                         if (result != ISC_R_SUCCESS)
 287                                 return (result);
 288                 } else
 289                         dns_name_split(name, i, NULL, zonename);
 290
 291                 /* ask SDLZ driver if the zone is supported */
 292                 dlzdatabase = view->dlzdatabase;
 293                 findzone = dlzdatabase->implementation->methods->findzone;
 294                 result = (*findzone)(dlzdatabase->implementation->driverarg,
 295                                      dlzdatabase->dbdata, dlzdatabase->mctx,
 296                                      view->rdclass, zonename, dbp);
 297                 if (result != ISC_R_NOTFOUND)
 298                         return (result);
 299         }
 300         return (ISC_R_NOTFOUND);
 301 }
 302
 303 /*%
 304  * Registers a DLZ driver.  This basically just adds the dlz
 305  * driver to the list of available drivers in the dlz_implementations list.
 306  */
 307 isc_result_t
 308 dns_dlzregister(const char *drivername, const dns_dlzmethods_t *methods,
 309                 void *driverarg, isc_mem_t *mctx,
 310                 dns_dlzimplementation_t **dlzimp)
 311 {
 312
 313         dns_dlzimplementation_t *dlz_imp;
 314
 315         /* Write debugging message to log */
 316         isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
 317                       DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),
 318                       "Registering DLZ driver '%s'", drivername);
 319
 320         /*
 321          * Performs checks to make sure data is as we expect it to be.
 322          */
 323         REQUIRE(drivername != NULL);
 324         REQUIRE(methods != NULL);
 325         REQUIRE(methods->create != NULL);
 326         REQUIRE(methods->destroy != NULL);
 327         REQUIRE(methods->findzone != NULL);
 328         REQUIRE(mctx != NULL);
 329         REQUIRE(dlzimp != NULL && *dlzimp == NULL);
 330
 331         /*
 332          * initialize the dlz_implementations list, this is guaranteed
 333          * to only really happen once.
 334          */
 335         RUNTIME_CHECK(isc_once_do(&once, dlz_initialize) == ISC_R_SUCCESS);
 336
 337         /* lock the dlz_implementations list so we can modify it. */
 338         RWLOCK(&dlz_implock, isc_rwlocktype_write);
 339
 340         /*
 341          * check that another already registered driver isn't using
 342          * the same name
 343          */
 344         dlz_imp = dlz_impfind(drivername);
 345         if (dlz_imp != NULL) {
 346                 isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
 347                               DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),
 348                               "DLZ Driver '%s' already registered",
 349                               drivername);
 350                 RWUNLOCK(&dlz_implock, isc_rwlocktype_write);
 351                 return (ISC_R_EXISTS);
 352         }
 353
 354         /*
 355          * Allocate memory for a dlz_implementation object.  Error if
 356          * we cannot.
 357          */
 358         dlz_imp = isc_mem_get(mctx, sizeof(dns_dlzimplementation_t));
 359         if (dlz_imp == NULL) {
 360                 RWUNLOCK(&dlz_implock, isc_rwlocktype_write);
 361                 return (ISC_R_NOMEMORY);
 362         }
 363
 364         /* Make sure memory region is set to all 0's */
 365         memset(dlz_imp, 0, sizeof(dns_dlzimplementation_t));
 366
 367         /* Store the data passed into this method */
 368         dlz_imp->name = drivername;
 369         dlz_imp->methods = methods;
 370         dlz_imp->mctx = NULL;
 371         dlz_imp->driverarg = driverarg;
 372
 373         /* attach the new dlz_implementation object to a memory context */
 374         isc_mem_attach(mctx, &dlz_imp->mctx);
 375
 376         /*
 377          * prepare the dlz_implementation object to be put in a list,
 378          * and append it to the list
 379          */
 380         ISC_LINK_INIT(dlz_imp, link);
 381         ISC_LIST_APPEND(dlz_implementations, dlz_imp, link);
 382
 383         /* Unlock the dlz_implementations list.  */
 384         RWUNLOCK(&dlz_implock, isc_rwlocktype_write);
 385
 386         /* Pass back the dlz_implementation that we created. */
 387         *dlzimp = dlz_imp;
 388
 389         return (ISC_R_SUCCESS);
 390 }
 391
 392 /*%
 393  * Helper function for dns_dlzstrtoargv().
 394  * Pardon the gratuitous recursion.
 395  */
 396 static isc_result_t
 397 dns_dlzstrtoargvsub(isc_mem_t *mctx, char *s, unsigned int *argcp,
 398                     char ***argvp, unsigned int n)
 399 {
 400         isc_result_t result;
 401
 402  restart:
 403         /* Discard leading whitespace. */
 404         while (*s == ' ' || *s == '\t')
 405                 s++;
 406
 407         if (*s == '\0') {
 408                 /* We have reached the end of the string. */
 409                 *argcp = n;
 410                 *argvp = isc_mem_get(mctx, n * sizeof(char *));
 411                 if (*argvp == NULL)
 412                         return (ISC_R_NOMEMORY);
 413         } else {
 414                 char *p = s;
 415                 while (*p != ' ' && *p != '\t' && *p != '\0' && *p != '{') {
 416                         if (*p == '\n') {
 417                                 *p = ' ';
 418                                 goto restart;
 419                         }
 420                         p++;
 421                 }
 422
 423                 /* do "grouping", items between { and } are one arg */
 424                 if (*p == '{') {
 425                         char *t = p;
 426                         /*
 427                          * shift all characters to left by 1 to get rid of '{'
 428                          */
 429                         while (*t != '\0') {
 430                                 t++;
 431                                 *(t-1) = *t;
 432                         }
 433                         while (*p != '\0' && *p != '}') {
 434                                 p++;
 435                         }
 436                         /* get rid of '}' character */
 437                         if (*p == '}') {
 438                                 *p = '\0';
 439                                 p++;
 440                         }
 441                         /* normal case, no "grouping" */
 442                 } else if (*p != '\0')
 443                         *p++ = '\0';
 444
 445                 result = dns_dlzstrtoargvsub(mctx, p, argcp, argvp, n + 1);
 446                 if (result != ISC_R_SUCCESS)
 447                         return (result);
 448                 (*argvp)[n] = s;
 449         }
 450         return (ISC_R_SUCCESS);
 451 }
 452
 453 /*%
 454  * Tokenize the string "s" into whitespace-separated words,
 455  * return the number of words in '*argcp' and an array
 456  * of pointers to the words in '*argvp'.  The caller
 457  * must free the array using isc_mem_put().  The string
 458  * is modified in-place.
 459  */
 460 isc_result_t
 461 dns_dlzstrtoargv(isc_mem_t *mctx, char *s,
 462                  unsigned int *argcp, char ***argvp)
 463 {
 464         return(dns_dlzstrtoargvsub(mctx, s, argcp, argvp, 0));
 465 }
 466
 467 /*%
 468  * Unregisters a DLZ driver.  This basically just removes the dlz
 469  * driver from the list of available drivers in the dlz_implementations list.
 470  */
 471 void
 472 dns_dlzunregister(dns_dlzimplementation_t **dlzimp) {
 473         dns_dlzimplementation_t *dlz_imp;
 474         isc_mem_t *mctx;
 475
 476         /* Write debugging message to log */
 477         isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
 478                       DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),
 479                       "Unregistering DLZ driver.");
 480
 481         /*
 482          * Performs checks to make sure data is as we expect it to be.
 483          */
 484         REQUIRE(dlzimp != NULL && *dlzimp != NULL);
 485
 486         /*
 487          * initialize the dlz_implementations list, this is guaranteed
 488          * to only really happen once.
 489          */
 490         RUNTIME_CHECK(isc_once_do(&once, dlz_initialize) == ISC_R_SUCCESS);
 491
 492         dlz_imp = *dlzimp;
 493
 494         /* lock the dlz_implementations list so we can modify it. */
 495         RWLOCK(&dlz_implock, isc_rwlocktype_write);
 496
 497         /* remove the dlz_implementation object from the list */
 498         ISC_LIST_UNLINK(dlz_implementations, dlz_imp, link);
 499         mctx = dlz_imp->mctx;
 500
 501         /*
 502          * return the memory back to the available memory pool and
 503          * remove it from the memory context.
 504          */
 505         isc_mem_put(mctx, dlz_imp, sizeof(dns_dlzimplementation_t));
 506         isc_mem_detach(&mctx);
 507
 508         /* Unlock the dlz_implementations list. */
 509         RWUNLOCK(&dlz_implock, isc_rwlocktype_write);
 510 }