adb.c

bind-3.2.

	dns_adbname_t *name;
	dns_adbname_t *next_name;
	isc_result_t result = ISC_FALSE;

	DP(CLEAN_LEVEL, "cleaning name bucket %d", bucket);

	LOCK(&adb->namelocks[bucket]);
	if (adb->name_sd[bucket]) {
		UNLOCK(&adb->namelocks[bucket]);
		return (result);
	}

	name = ISC_LIST_HEAD(adb->names[bucket]);
	while (name != NULL) {
		next_name = ISC_LIST_NEXT(name, plink);
		INSIST(result == ISC_FALSE);
		result = check_expire_namehooks(name, now);
		if (!result)
			result = check_expire_name(&name, now);
		name = next_name;
	}
	UNLOCK(&adb->namelocks[bucket]);
	return (result);
}

/*
 * ADB must be locked, and no other locks held.
 */
static isc_boolean_t
cleanup_entries(dns_adb_t *adb, int bucket, isc_stdtime_t now) {
	dns_adbentry_t *entry, *next_entry;
	isc_boolean_t result = ISC_FALSE;

	DP(CLEAN_LEVEL, "cleaning entry bucket %d", bucket);

	LOCK(&adb->entrylocks[bucket]);
	entry = ISC_LIST_HEAD(adb->entries[bucket]);
	while (entry != NULL) {
		next_entry = ISC_LIST_NEXT(entry, plink);
		INSIST(result == ISC_FALSE);
		result = check_expire_entry(adb, &entry, now);
		entry = next_entry;
	}
	UNLOCK(&adb->entrylocks[bucket]);
	return (result);
}

static void
timer_cleanup(isc_task_t *task, isc_event_t *ev) {
	dns_adb_t *adb;
	isc_stdtime_t now;
	unsigned int i;

	UNUSED(task);

	adb = ev->ev_arg;
	INSIST(DNS_ADB_VALID(adb));

	LOCK(&adb->lock);

	isc_stdtime_get(&now);

	for (i = 0 ; i < CLEAN_BUCKETS ; i++) {
		/*
		 * Call our cleanup routines.
		 */
		RUNTIME_CHECK(cleanup_names(adb, adb->next_cleanbucket, now) ==
			      ISC_FALSE);
		RUNTIME_CHECK(cleanup_entries(adb, adb->next_cleanbucket, now)
			      == ISC_FALSE);

		/*
		 * Set the next bucket to be cleaned.
		 */
		adb->next_cleanbucket++;
		if (adb->next_cleanbucket >= NBUCKETS) {
			adb->next_cleanbucket = 0;
#ifdef DUMP_ADB_AFTER_CLEANING
			dump_adb(adb, stdout, ISC_TRUE);
#endif
		}
	}

	/*
	 * Reset the timer.
	 * XXXDCL isc_timer_reset might return ISC_R_UNEXPECTED or
	 * ISC_R_NOMEMORY, but it isn't clear what could be done here
	 * if either one of those things happened.
	 */
	(void)isc_timer_reset(adb->timer, isc_timertype_once, NULL,
			      &adb->tick_interval, ISC_FALSE);

	UNLOCK(&adb->lock);

	isc_event_free(&ev);
}

static void
destroy(dns_adb_t *adb) {
	adb->magic = 0;

	/*
	 * The timer is already dead, from the task's shutdown callback.
	 */
	isc_task_detach(&adb->task);

	isc_mempool_destroy(&adb->nmp);
	isc_mempool_destroy(&adb->nhmp);
	isc_mempool_destroy(&adb->zimp);
	isc_mempool_destroy(&adb->emp);
	isc_mempool_destroy(&adb->ahmp);
	isc_mempool_destroy(&adb->aimp);
	isc_mempool_destroy(&adb->afmp);
	isc_mempool_destroy(&adb->af6mp);

	isc_mutexblock_destroy(adb->entrylocks, NBUCKETS);
	isc_mutexblock_destroy(adb->namelocks, NBUCKETS);

	DESTROYLOCK(&adb->reflock);
	DESTROYLOCK(&adb->lock);
	DESTROYLOCK(&adb->mplock);

	isc_mem_put(adb->mctx, adb, sizeof (dns_adb_t));
}


/*
 * Public functions.
 */

isc_result_t
dns_adb_create(isc_mem_t *mem, dns_view_t *view, isc_timermgr_t *timermgr,
	       isc_taskmgr_t *taskmgr, dns_adb_t **newadb)
{
	dns_adb_t *adb;
	isc_result_t result;
	int i;

	REQUIRE(mem != NULL);
	REQUIRE(view != NULL);
	REQUIRE(timermgr != NULL);
	REQUIRE(taskmgr != NULL);
	REQUIRE(newadb != NULL && *newadb == NULL);

	adb = isc_mem_get(mem, sizeof (dns_adb_t));
	if (adb == NULL)
		return (ISC_R_NOMEMORY);

	/*
	 * Initialize things here that cannot fail, and especially things
	 * that must be NULL for the error return to work properly.
	 */
	adb->magic = 0;
	adb->erefcnt = 1;
	adb->irefcnt = 0;
	adb->nmp = NULL;
	adb->nhmp = NULL;
	adb->zimp = NULL;
	adb->emp = NULL;
	adb->ahmp = NULL;
	adb->aimp = NULL;
	adb->afmp = NULL;
	adb->af6mp = NULL;
	adb->task = NULL;
	adb->timer = NULL;
	adb->mctx = mem;
	adb->view = view;
	adb->timermgr = timermgr;
	adb->taskmgr = taskmgr;
	adb->next_cleanbucket = 0;
	ISC_EVENT_INIT(&adb->cevent, sizeof adb->cevent, 0, NULL,
		       DNS_EVENT_ADBCONTROL, shutdown_task, adb,
		       adb, NULL, NULL);
	adb->cevent_sent = ISC_FALSE;
	adb->shutting_down = ISC_FALSE;
	ISC_LIST_INIT(adb->whenshutdown);

	result = isc_mutex_init(&adb->lock);
	if (result != ISC_R_SUCCESS)
		goto fail0b;

	result = isc_mutex_init(&adb->mplock);
	if (result != ISC_R_SUCCESS)
		goto fail0c;

	result = isc_mutex_init(&adb->reflock);
	if (result != ISC_R_SUCCESS)
		goto fail0d;

	/*
	 * Initialize the bucket locks for names and elements.
	 * May as well initialize the list heads, too.
	 */
	result = isc_mutexblock_init(adb->namelocks, NBUCKETS);
	if (result != ISC_R_SUCCESS)
		goto fail1;
	for (i = 0 ; i < NBUCKETS ; i++) {
		ISC_LIST_INIT(adb->names[i]);
		adb->name_sd[i] = ISC_FALSE;
		adb->name_refcnt[i] = 0;
		adb->irefcnt++;
	}
	for (i = 0 ; i < NBUCKETS ; i++) {
		ISC_LIST_INIT(adb->entries[i]);
		adb->entry_sd[i] = ISC_FALSE;
		adb->entry_refcnt[i] = 0;
		adb->irefcnt++;
	}
	result = isc_mutexblock_init(adb->entrylocks, NBUCKETS);
	if (result != ISC_R_SUCCESS)
		goto fail2;

	/*
	 * Memory pools
	 */
#define MPINIT(t, p, n) do { \
	result = isc_mempool_create(mem, sizeof (t), &(p)); \
	if (result != ISC_R_SUCCESS) \
		goto fail3; \
	isc_mempool_setfreemax((p), FREE_ITEMS); \
	isc_mempool_setfillcount((p), FILL_COUNT); \
	isc_mempool_setname((p), n); \
	isc_mempool_associatelock((p), &adb->mplock); \
} while (0)

	MPINIT(dns_adbname_t, adb->nmp, "adbname");
	MPINIT(dns_adbnamehook_t, adb->nhmp, "adbnamehook");
	MPINIT(dns_adbzoneinfo_t, adb->zimp, "adbzoneinfo");
	MPINIT(dns_adbentry_t, adb->emp, "adbentry");
	MPINIT(dns_adbfind_t, adb->ahmp, "adbfind");
	MPINIT(dns_adbaddrinfo_t, adb->aimp, "adbaddrinfo");
	MPINIT(dns_adbfetch_t, adb->afmp, "adbfetch");
	MPINIT(dns_adbfetch6_t, adb->af6mp, "adbfetch6");

#undef MPINIT

	/*
	 * Allocate a timer and a task for our periodic cleanup.
	 */
	result = isc_task_create(adb->taskmgr, 0, &adb->task);
	if (result != ISC_R_SUCCESS)
		goto fail3;
	isc_task_setname(adb->task, "ADB", adb);
	/*
	 * XXXMLG When this is changed to be a config file option,
	 */
	isc_interval_set(&adb->tick_interval, CLEAN_SECONDS, 0);
	result = isc_timer_create(adb->timermgr, isc_timertype_once,
				  NULL, &adb->tick_interval, adb->task,
				  timer_cleanup, adb, &adb->timer);
	if (result != ISC_R_SUCCESS)
		goto fail3;

	DP(5,
	   "Cleaning interval for adb:  "
	   "%u buckets every %u seconds, %u buckets in system, %u cl.interval",
	   CLEAN_BUCKETS, CLEAN_SECONDS, NBUCKETS, CLEAN_PERIOD);

	/*
	 * Normal return.
	 */
	adb->magic = DNS_ADB_MAGIC;
	*newadb = adb;
	return (ISC_R_SUCCESS);

 fail3:
	if (adb->task != NULL)
		isc_task_detach(&adb->task);
	if (adb->timer != NULL)
		isc_timer_detach(&adb->timer);

	/* clean up entrylocks */
	isc_mutexblock_destroy(adb->entrylocks, NBUCKETS);

 fail2: /* clean up namelocks */
	isc_mutexblock_destroy(adb->namelocks, NBUCKETS);

 fail1: /* clean up only allocated memory */
	if (adb->nmp != NULL)
		isc_mempool_destroy(&adb->nmp);
	if (adb->nhmp != NULL)
		isc_mempool_destroy(&adb->nhmp);
	if (adb->zimp != NULL)
		isc_mempool_destroy(&adb->zimp);
	if (adb->emp != NULL)
		isc_mempool_destroy(&adb->emp);
	if (adb->ahmp != NULL)
		isc_mempool_destroy(&adb->ahmp);
	if (adb->aimp != NULL)
		isc_mempool_destroy(&adb->aimp);
	if (adb->afmp != NULL)
		isc_mempool_destroy(&adb->afmp);
	if (adb->af6mp != NULL)
		isc_mempool_destroy(&adb->af6mp);

	DESTROYLOCK(&adb->reflock);
 fail0d:
	DESTROYLOCK(&adb->mplock);
 fail0c:
	DESTROYLOCK(&adb->lock);
 fail0b:
	isc_mem_put(mem, adb, sizeof (dns_adb_t));

	return (result);
}

void
dns_adb_attach(dns_adb_t *adb, dns_adb_t **adbx) {

	REQUIRE(DNS_ADB_VALID(adb));
	REQUIRE(adbx != NULL && *adbx == NULL);

	inc_adb_erefcnt(adb);
	*adbx = adb;
}

void
dns_adb_detach(dns_adb_t **adbx) {
	dns_adb_t *adb;
	isc_boolean_t need_exit_check;

	REQUIRE(adbx != NULL && DNS_ADB_VALID(*adbx));

	adb = *adbx;
	*adbx = NULL;

	INSIST(adb->erefcnt > 0);

	LOCK(&adb->reflock);
	adb->erefcnt--;
	need_exit_check = ISC_TF(adb->erefcnt == 0 && adb->irefcnt == 0);
	UNLOCK(&adb->reflock);

	if (need_exit_check) {
		LOCK(&adb->lock);
		INSIST(adb->shutting_down);
		check_exit(adb);
		UNLOCK(&adb->lock);
	}
}

void
dns_adb_whenshutdown(dns_adb_t *adb, isc_task_t *task, isc_event_t **eventp) {
	isc_task_t *clone;
	isc_event_t *event;
	isc_boolean_t zeroirefcnt = ISC_FALSE;

	/*
	 * Send '*eventp' to 'task' when 'adb' has shutdown.
	 */

	REQUIRE(DNS_ADB_VALID(adb));
	REQUIRE(eventp != NULL);

	event = *eventp;
	*eventp = NULL;

	LOCK(&adb->lock);

	LOCK(&adb->reflock);
	zeroirefcnt = ISC_TF(adb->irefcnt == 0);

	if (adb->shutting_down && zeroirefcnt &&
	    isc_mempool_getallocated(adb->ahmp) == 0) {
		/*
		 * We're already shutdown.  Send the event.
		 */
		event->ev_sender = adb;
		isc_task_send(task, &event);
	} else {
		clone = NULL;
		isc_task_attach(task, &clone);
		event->ev_sender = clone;
		ISC_LIST_APPEND(adb->whenshutdown, event, ev_link);
	}

	UNLOCK(&adb->reflock);
	UNLOCK(&adb->lock);
}

void
dns_adb_shutdown(dns_adb_t *adb) {
	isc_boolean_t need_check_exit;

	/*
	 * Shutdown 'adb'.
	 */

	LOCK(&adb->lock);

	if (!adb->shutting_down) {
		adb->shutting_down = ISC_TRUE;
		need_check_exit = shutdown_names(adb);
		if (!need_check_exit)
			need_check_exit = shutdown_entries(adb);
		if (need_check_exit)
			check_exit(adb);
	}

	UNLOCK(&adb->lock);
}

isc_result_t
dns_adb_createfind(dns_adb_t *adb, isc_task_t *task, isc_taskaction_t action,
		   void *arg, dns_name_t *name, dns_name_t *zone,
		   unsigned int options, isc_stdtime_t now, dns_name_t *target,
		   in_port_t port, dns_adbfind_t **findp)
{
	dns_adbfind_t *find;
	dns_adbname_t *adbname;
	int bucket;
	isc_boolean_t want_event, start_at_zone, alias, have_address;
	isc_result_t result;
	unsigned int wanted_addresses;
	unsigned int wanted_fetches;
	unsigned int query_pending;

	REQUIRE(DNS_ADB_VALID(adb));
	if (task != NULL) {
		REQUIRE(action != NULL);
	}
	REQUIRE(name != NULL);
	REQUIRE(zone != NULL);
	REQUIRE(findp != NULL && *findp == NULL);
	REQUIRE(target == NULL || dns_name_hasbuffer(target));

	REQUIRE((options & DNS_ADBFIND_ADDRESSMASK) != 0);

	result = ISC_R_UNEXPECTED;
	wanted_addresses = (options & DNS_ADBFIND_ADDRESSMASK);
	wanted_fetches = 0;
	query_pending = 0;
	want_event = ISC_FALSE;
	start_at_zone = ISC_FALSE;
	alias = ISC_FALSE;

	if (now == 0)
		isc_stdtime_get(&now);

	/*
	 * XXXMLG  Move this comment somewhere else!
	 *
	 * Look up the name in our internal database.
	 *
	 * Possibilities:  Note that these are not always exclusive.
	 *
	 *	No name found.  In this case, allocate a new name header and
	 *	an initial namehook or two.  If any of these allocations
	 *	fail, clean up and return ISC_R_NOMEMORY.
	 *
	 *	Name found, valid addresses present.  Allocate one addrinfo
	 *	structure for each found and append it to the linked list
	 *	of addresses for this header.
	 *
	 *	Name found, queries pending.  In this case, if a task was
	 *	passed in, allocate a job id, attach it to the name's job
	 *	list and remember to tell the caller that there will be
	 *	more info coming later.
	 */

	find = new_adbfind(adb);
	if (find == NULL)
		return (ISC_R_NOMEMORY);

	find->port = port;

	/*
	 * Remember what types of addresses we are interested in.
	 */
	find->options = options;
	find->flags |= wanted_addresses;
	if (FIND_WANTEVENT(find)) {
		REQUIRE(task != NULL);
	}

	/*
	 * Try to see if we know anything about this name at all.
	 */
	bucket = DNS_ADB_INVALIDBUCKET;
	adbname = find_name_and_lock(adb, name, find->options, &bucket);
	if (adb->name_sd[bucket]) {
		DP(DEF_LEVEL,
		   "dns_adb_createfind: returning ISC_R_SHUTTINGDOWN");
		RUNTIME_CHECK(free_adbfind(adb, &find) == ISC_FALSE);
		result = ISC_R_SHUTTINGDOWN;
		goto out;
	}

	/*
	 * Nothing found.  Allocate a new adbname structure for this name.
	 */
	if (adbname == NULL) {
		adbname = new_adbname(adb, name);
		if (adbname == NULL) {
			RUNTIME_CHECK(free_adbfind(adb, &find) == ISC_FALSE);
			result = ISC_R_NOMEMORY;
			goto out;
		}
		link_name(adb, bucket, adbname);
		if (FIND_HINTOK(find))
			adbname->flags |= NAME_HINT_OK;
		if (FIND_GLUEOK(find))
			adbname->flags |= NAME_GLUE_OK;
		if (FIND_STARTATZONE(find))
			adbname->flags |= NAME_STARTATZONE;
	}

	/*
	 * Expire old entries, etc.
	 */
	RUNTIME_CHECK(check_expire_namehook