/*

 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")

 *

 * SPDX-License-Identifier: MPL-2.0 AND ISC

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, you can obtain one at https://mozilla.org/MPL/2.0/.

 *

 * See the COPYRIGHT file distributed with this work for additional

 * information regarding copyright ownership.

 */

/*

 * Copyright (C) 2002 Stichting NLnet, Netherlands, stichting@nlnet.nl.

 *

 * Permission to use, copy, modify, and distribute this software for any

 * purpose with or without fee is hereby granted, provided that the

 * above copyright notice and this permission notice appear in all

 * copies.

 *

 * THE SOFTWARE IS PROVIDED "AS IS" AND STICHTING NLNET

 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL

 * STICHTING NLNET BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR

 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS

 * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE

 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE

 * USE OR PERFORMANCE OF THIS SOFTWARE.

 *

 * The development of Dynamically Loadable Zones (DLZ) for Bind 9 was

 * conceived and contributed by Rob Butler.

 *

 * Permission to use, copy, modify, and distribute this software for any

 * purpose with or without fee is hereby granted, provided that the

 * above copyright notice and this permission notice appear in all

 * copies.

 *

 * THE SOFTWARE IS PROVIDED "AS IS" AND ROB BUTLER

 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL

 * ROB BUTLER BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR

 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS

 * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE

 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE

 * USE OR PERFORMANCE OF THIS SOFTWARE.

 */

/*! \file */

/***

 *** Imports

 ***/

#include <stdbool.h>

#include <isc/buffer.h>

#include <isc/commandline.h>

#include <isc/magic.h>

#include <isc/mem.h>

#include <isc/netmgr.h>

#include <isc/once.h>

#include <isc/random.h>

#include <isc/rwlock.h>

#include <isc/string.h>

#include <isc/util.h>

#include <dns/db.h>

#include <dns/dlz.h>

#include <dns/fixedname.h>

#include <dns/log.h>

#include <dns/master.h>

#include <dns/ssu.h>

#include <dns/zone.h>

/***

 *** Supported DLZ DB Implementations Registry

 ***/

static ISC_LIST(dns_dlzimplementation_t) dlz_implementations;

static isc_rwlock_t dlz_implock;

static isc_once_t once = ISC_ONCE_INIT;

static void

dlz_initialize(void) {

  isc_rwlock_init(&dlz_implock);

  ISC_LIST_INIT(dlz_implementations);

}

/*%

 * Searches the dlz_implementations list for a driver matching name.

 */

static dns_dlzimplementation_t *

dlz_impfind(const char *name) {

  dns_dlzimplementation_t *imp;

  for (imp = ISC_LIST_HEAD(dlz_implementations); imp != NULL;

       imp = ISC_LIST_NEXT(imp, link))

  {

    if (strcasecmp(name, imp->name) == 0) {

      return (imp);

    }

  }

  return (NULL);

}

/***

 *** Basic DLZ Methods

 ***/

isc_result_t

dns_dlzallowzonexfr(dns_view_t *view, const dns_name_t *name,

        const isc_sockaddr_t *clientaddr, dns_db_t **dbp) {

  isc_result_t result = ISC_R_NOTFOUND;

  dns_dlzallowzonexfr_t allowzonexfr;

  dns_dlzdb_t *dlzdb;

  /*

   * Performs checks to make sure data is as we expect it to be.

   */

  REQUIRE(name != NULL);

  REQUIRE(dbp != NULL && *dbp == NULL);

  /*

   * Find a driver in which the zone exists and transfer is supported

   */

  for (dlzdb = ISC_LIST_HEAD(view->dlz_searched); dlzdb != NULL;

       dlzdb = ISC_LIST_NEXT(dlzdb, link))

  {

    REQUIRE(DNS_DLZ_VALID(dlzdb));

    allowzonexfr = dlzdb->implementation->methods->allowzonexfr;

    result = (*allowzonexfr)(dlzdb->implementation->driverarg,

           dlzdb->dbdata, dlzdb->mctx,

           view->rdclass, name, clientaddr, dbp);

    /*

     * In these cases, we found the right database. Non-success

     * result codes indicate the zone might not transfer.

     */

    switch (result) {

    case ISC_R_SUCCESS:

    case ISC_R_NOPERM:

    case ISC_R_DEFAULT:

      return (result);

    default:

      break;

    }

  }

  if (result == ISC_R_NOTIMPLEMENTED) {

    result = ISC_R_NOTFOUND;

  }

  return (result);

}

isc_result_t

dns_dlzcreate(isc_mem_t *mctx, const char *dlzname, const char *drivername,

        unsigned int argc, char *argv[], dns_dlzdb_t **dbp) {

  dns_dlzimplementation_t *impinfo;

  isc_result_t result;

  dns_dlzdb_t *db = NULL;

  /*

   * initialize the dlz_implementations list, this is guaranteed

   * to only really happen once.

   */

  isc_once_do(&once, dlz_initialize);

  /*

   * Performs checks to make sure data is as we expect it to be.

   */

  REQUIRE(dbp != NULL && *dbp == NULL);

  REQUIRE(dlzname != NULL);

  REQUIRE(drivername != NULL);

  REQUIRE(mctx != NULL);

  /* write log message */

  isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_DLZ,

          ISC_LOG_INFO, "Loading '%s' using driver %s", dlzname,

          drivername);

  /* lock the dlz_implementations list so we can search it. */

  RWLOCK(&dlz_implock, isc_rwlocktype_read);

  /* search for the driver implementation  */

  impinfo = dlz_impfind(drivername);

  if (impinfo == NULL) {

    RWUNLOCK(&dlz_implock, isc_rwlocktype_read);

    isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,

            DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,

            "unsupported DLZ database driver '%s'."

            "  %s not loaded.",

            drivername, dlzname);

    return (ISC_R_NOTFOUND);

  }

  /* Allocate memory to hold the DLZ database driver */

  db = isc_mem_get(mctx, sizeof(*db));

  *db = (dns_dlzdb_t){

    .implementation = impinfo,

  };

  ISC_LINK_INIT(db, link);

  if (dlzname != NULL) {

    db->dlzname = isc_mem_strdup(mctx, dlzname);

  }

  /* Create a new database using implementation 'drivername'. */

  result = ((impinfo->methods->create)(mctx, dlzname, argc, argv,

               impinfo->driverarg, &db->dbdata));

  RWUNLOCK(&dlz_implock, isc_rwlocktype_read);

  /* mark the DLZ driver as valid */

  if (result != ISC_R_SUCCESS) {

    goto failure;

  }

  db->magic = DNS_DLZ_MAGIC;

  isc_mem_attach(mctx, &db->mctx);

  isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_DLZ,

          ISC_LOG_DEBUG(2), "DLZ driver loaded successfully.");

  *dbp = db;

  return (ISC_R_SUCCESS);

failure:

  isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_DLZ,

          ISC_LOG_ERROR, "DLZ driver failed to load.");

  /* impinfo->methods->create failed. */

  isc_mem_free(mctx, db->dlzname);

  isc_mem_put(mctx, db, sizeof(*db));

  return (result);

}

void

dns_dlzdestroy(dns_dlzdb_t **dbp) {

  dns_dlzdestroy_t destroy;

  dns_dlzdb_t *db;

  /* Write debugging message to log */

  isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_DLZ,

          ISC_LOG_DEBUG(2), "Unloading DLZ driver.");

  /*

   * Perform checks to make sure data is as we expect it to be.

   */

  REQUIRE(dbp != NULL && DNS_DLZ_VALID(*dbp));

  db = *dbp;

  *dbp = NULL;

  if (db->ssutable != NULL) {

    dns_ssutable_detach(&db->ssutable);

  }

  /* call the drivers destroy method */

  if (db->dlzname != NULL) {

    isc_mem_free(db->mctx, db->dlzname);

  }

  destroy = db->implementation->methods->destroy;

  (*destroy)(db->implementation->driverarg, db->dbdata);

  /* return memory and detach */

  isc_mem_putanddetach(&db->mctx, db, sizeof(*db));

}

/*%

 * Registers a DLZ driver.  This basically just adds the dlz

 * driver to the list of available drivers in the dlz_implementations list.

 */

isc_result_t

dns_dlzregister(const char *drivername, const dns_dlzmethods_t *methods,

    void *driverarg, isc_mem_t *mctx,

    dns_dlzimplementation_t **dlzimp) {

  dns_dlzimplementation_t *dlz_imp;

  /* Write debugging message to log */

  isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_DLZ,

          ISC_LOG_DEBUG(2), "Registering DLZ driver '%s'",

          drivername);

  /*

   * Performs checks to make sure data is as we expect it to be.

   */

  REQUIRE(drivername != NULL);

  REQUIRE(methods != NULL);

  REQUIRE(methods->create != NULL);

  REQUIRE(methods->destroy != NULL);

  REQUIRE(methods->findzone != NULL);

  REQUIRE(mctx != NULL);

  REQUIRE(dlzimp != NULL && *dlzimp == NULL);

  /*

   * initialize the dlz_implementations list, this is guaranteed

   * to only really happen once.

   */

  isc_once_do(&once, dlz_initialize);

  /* lock the dlz_implementations list so we can modify it. */

  RWLOCK(&dlz_implock, isc_rwlocktype_write);

  /*

   * check that another already registered driver isn't using

   * the same name

   */

  dlz_imp = dlz_impfind(drivername);

  if (dlz_imp != NULL) {

    isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,

            DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),

            "DLZ Driver '%s' already registered", drivername);

    RWUNLOCK(&dlz_implock, isc_rwlocktype_write);

    return (ISC_R_EXISTS);

  }

  /*

   * Allocate memory for a dlz_implementation object.  Error if

   * we cannot.

   */

  dlz_imp = isc_mem_get(mctx, sizeof(*dlz_imp));

  *dlz_imp = (dns_dlzimplementation_t){

    .name = drivername,

    .methods = methods,

    .driverarg = driverarg,

  };

  /* attach the new dlz_implementation object to a memory context */

  isc_mem_attach(mctx, &dlz_imp->mctx);

  /*

   * prepare the dlz_implementation object to be put in a list,

   * and append it to the list

   */

  ISC_LINK_INIT(dlz_imp, link);

  ISC_LIST_APPEND(dlz_implementations, dlz_imp, link);

  /* Unlock the dlz_implementations list.  */

  RWUNLOCK(&dlz_implock, isc_rwlocktype_write);

  /* Pass back the dlz_implementation that we created. */

  *dlzimp = dlz_imp;

  return (ISC_R_SUCCESS);

}

/*%

 * Tokenize the string "s" into whitespace-separated words,

 * return the number of words in '*argcp' and an array

 * of pointers to the words in '*argvp'.  The caller

 * must free the array using isc_mem_put().  The string

 * is modified in-place.

 */

isc_result_t

dns_dlzstrtoargv(isc_mem_t *mctx, char *s, unsigned int *argcp, char ***argvp) {

  return (isc_commandline_strtoargv(mctx, s, argcp, argvp, 0));

}

/*%

 * Unregisters a DLZ driver.  This basically just removes the dlz

 * driver from the list of available drivers in the dlz_implementations list.

 */

void

dns_dlzunregister(dns_dlzimplementation_t **dlzimp) {

  dns_dlzimplementation_t *dlz_imp;

  /* Write debugging message to log */

  isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_DLZ,

          ISC_LOG_DEBUG(2), "Unregistering DLZ driver.");

  /*

   * Performs checks to make sure data is as we expect it to be.

   */

  REQUIRE(dlzimp != NULL && *dlzimp != NULL);

  /*

   * initialize the dlz_implementations list, this is guaranteed

   * to only really happen once.

   */

  isc_once_do(&once, dlz_initialize);

  dlz_imp = *dlzimp;

  /* lock the dlz_implementations list so we can modify it. */

  RWLOCK(&dlz_implock, isc_rwlocktype_write);

  /* remove the dlz_implementation object from the list */

  ISC_LIST_UNLINK(dlz_implementations, dlz_imp, link);

  /*

   * Return the memory back to the available memory pool and

   * remove it from the memory context.

   */

  isc_mem_putanddetach(&dlz_imp->mctx, dlz_imp, sizeof(*dlz_imp));

  /* Unlock the dlz_implementations list. */

  RWUNLOCK(&dlz_implock, isc_rwlocktype_write);

}

/*

 * Create a writeable DLZ zone. This can be called by DLZ drivers

 * during configure() to create a zone that can be updated. The zone

 * type is set to dns_zone_dlz, which is equivalent to a primary zone

 *

 * This function uses a callback setup in dns_dlzconfigure() to call

 * into the server zone code to setup the remaining pieces of server

 * specific functionality on the zone

 */

isc_result_t

dns_dlz_writeablezone(dns_view_t *view, dns_dlzdb_t *dlzdb,

          const char *zone_name) {

  dns_zone_t *zone = NULL;

  dns_zone_t *dupzone = NULL;

  isc_result_t result;

  isc_buffer_t buffer;

  dns_fixedname_t fixorigin;

  dns_name_t *origin;

  REQUIRE(DNS_DLZ_VALID(dlzdb));

  REQUIRE(dlzdb->configure_callback != NULL);

  isc_buffer_constinit(&buffer, zone_name, strlen(zone_name));

  isc_buffer_add(&buffer, strlen(zone_name));

  dns_fixedname_init(&fixorigin);

  result = dns_name_fromtext(dns_fixedname_name(&fixorigin), &buffer,

           dns_rootname, 0, NULL);

  if (result != ISC_R_SUCCESS) {

    goto cleanup;

  }

  origin = dns_fixedname_name(&fixorigin);

  if (!dlzdb->search) {

    isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,

            DNS_LOGMODULE_DLZ, ISC_LOG_WARNING,

            "DLZ %s has 'search no;', but attempted to "

            "register writeable zone %s.",

            dlzdb->dlzname, zone_name);

    result = ISC_R_SUCCESS;

    goto cleanup;

  }

  /* See if the zone already exists */

  result = dns_view_findzone(view, origin, DNS_ZTFIND_EXACT, &dupzone);

  if (result == ISC_R_SUCCESS) {

    dns_zone_detach(&dupzone);

    result = ISC_R_EXISTS;

    goto cleanup;

  }

  INSIST(dupzone == NULL);

  /* Create it */

  result = dns_zone_create(&zone, view->mctx, 0);

  if (result != ISC_R_SUCCESS) {

    goto cleanup;

  }

  result = dns_zone_setorigin(zone, origin);

  if (result != ISC_R_SUCCESS) {

    goto cleanup;

  }

  dns_zone_setview(zone, view);

  dns_zone_setadded(zone, true);

  if (dlzdb->ssutable == NULL) {

    dns_ssutable_createdlz(dlzdb->mctx, &dlzdb->ssutable, dlzdb);

  }

  dns_zone_setssutable(zone, dlzdb->ssutable);

  result = dlzdb->configure_callback(view, dlzdb, zone);

  if (result != ISC_R_SUCCESS) {

    goto cleanup;

  }

  result = dns_view_addzone(view, zone);

cleanup:

  if (zone != NULL) {

    dns_zone_detach(&zone);

  }

  return (result);

}

/*%

 * Configure a DLZ driver. This is optional, and if supplied gives

 * the backend an opportunity to configure parameters related to DLZ.

 */

isc_result_t

dns_dlzconfigure(dns_view_t *view, dns_dlzdb_t *dlzdb,

     dlzconfigure_callback_t callback) {

  dns_dlzimplementation_t *impl;

  isc_result_t result;

  REQUIRE(DNS_DLZ_VALID(dlzdb));

  REQUIRE(dlzdb->implementation != NULL);

  impl = dlzdb->implementation;

  if (impl->methods->configure == NULL) {

    return (ISC_R_SUCCESS);

  }

  dlzdb->configure_callback = callback;

  result = impl->methods->configure(impl->driverarg, dlzdb->dbdata, view,

            dlzdb);

  return (result);

}

bool

dns_dlz_ssumatch(dns_dlzdb_t *dlzdatabase, const dns_name_t *signer,

     const dns_name_t *name, const isc_netaddr_t *tcpaddr,

     dns_rdatatype_t type, const dst_key_t *key) {

  dns_dlzimplementation_t *impl;

  bool r;

  REQUIRE(dlzdatabase != NULL);

  REQUIRE(dlzdatabase->implementation != NULL);

  REQUIRE(dlzdatabase->implementation->methods != NULL);

  impl = dlzdatabase->implementation;

  if (impl->methods->ssumatch == NULL) {

    isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,

            DNS_LOGMODULE_DLZ, ISC_LOG_INFO,

            "No ssumatch method for DLZ database");

    return (false);

  }

  r = impl->methods->ssumatch(signer, name, tcpaddr, type, key,

            impl->driverarg, dlzdatabase->dbdata);

  return (r);

}