adb.c

bind 9.3结合mysql数据库

	dns_adbaddrinfo_t *ai;

	ai = isc_mempool_get(adb->aimp);
	if (ai == NULL)
		return (NULL);

	ai->magic = DNS_ADBADDRINFO_MAGIC;
	ai->sockaddr = entry->sockaddr;
	isc_sockaddr_setport(&ai->sockaddr, port);
	ai->srtt = entry->srtt;
	ai->flags = entry->flags;
	ai->entry = entry;
	ISC_LINK_INIT(ai, publink);

	return (ai);
}

static inline void
free_adbaddrinfo(dns_adb_t *adb, dns_adbaddrinfo_t **ainfo) {
	dns_adbaddrinfo_t *ai;

	INSIST(ainfo != NULL && DNS_ADBADDRINFO_VALID(*ainfo));
	ai = *ainfo;
	*ainfo = NULL;

	INSIST(ai->entry == NULL);
	INSIST(!ISC_LINK_LINKED(ai, publink));

	ai->magic = 0;

	isc_mempool_put(adb->aimp, ai);
}

/*
 * Search for the name.  NOTE:  The bucket is kept locked on both
 * success and failure, so it must always be unlocked by the caller!
 *
 * On the first call to this function, *bucketp must be set to
 * DNS_ADB_INVALIDBUCKET.
 */
static inline dns_adbname_t *
find_name_and_lock(dns_adb_t *adb, dns_name_t *name,
		   unsigned int options, int *bucketp)
{
	dns_adbname_t *adbname;
	int bucket;

	bucket = dns_name_fullhash(name, ISC_FALSE) % NBUCKETS;

	if (*bucketp == DNS_ADB_INVALIDBUCKET) {
		LOCK(&adb->namelocks[bucket]);
		*bucketp = bucket;
	} else if (*bucketp != bucket) {
		UNLOCK(&adb->namelocks[*bucketp]);
		LOCK(&adb->namelocks[bucket]);
		*bucketp = bucket;
	}

	adbname = ISC_LIST_HEAD(adb->names[bucket]);
	while (adbname != NULL) {
		if (!NAME_DEAD(adbname)) {
			if (dns_name_equal(name, &adbname->name)
			    && GLUEHINT_OK(adbname, options)
			    && STARTATZONE_MATCHES(adbname, options))
				return (adbname);
		}
		adbname = ISC_LIST_NEXT(adbname, plink);
	}

	return (NULL);
}

/*
 * Search for the address.  NOTE:  The bucket is kept locked on both
 * success and failure, so it must always be unlocked by the caller.
 *
 * On the first call to this function, *bucketp must be set to
 * DNS_ADB_INVALIDBUCKET.  This will cause a lock to occur.  On
 * later calls (within the same "lock path") it can be left alone, so
 * if this function is called multiple times locking is only done if
 * the bucket changes.
 */
static inline dns_adbentry_t *
find_entry_and_lock(dns_adb_t *adb, isc_sockaddr_t *addr, int *bucketp) {
	dns_adbentry_t *entry;
	int bucket;

	bucket = isc_sockaddr_hash(addr, ISC_TRUE) % NBUCKETS;

	if (*bucketp == DNS_ADB_INVALIDBUCKET) {
		LOCK(&adb->entrylocks[bucket]);
		*bucketp = bucket;
	} else if (*bucketp != bucket) {
		UNLOCK(&adb->entrylocks[*bucketp]);
		LOCK(&adb->entrylocks[bucket]);
		*bucketp = bucket;
	}

	entry = ISC_LIST_HEAD(adb->entries[bucket]);
	while (entry != NULL) {
		if (isc_sockaddr_equal(addr, &entry->sockaddr))
			return (entry);
		entry = ISC_LIST_NEXT(entry, plink);
	}

	return (NULL);
}

/*
 * Entry bucket MUST be locked!
 */
static isc_boolean_t
entry_is_bad_for_zone(dns_adb_t *adb, dns_adbentry_t *entry, dns_name_t *zone,
		      isc_stdtime_t now)
{
	dns_adbzoneinfo_t *zi, *next_zi;
	isc_boolean_t is_bad;

	is_bad = ISC_FALSE;

	zi = ISC_LIST_HEAD(entry->zoneinfo);
	if (zi == NULL)
		return (ISC_FALSE);
	while (zi != NULL) {
		next_zi = ISC_LIST_NEXT(zi, plink);

		/*
		 * Has the entry expired?
		 */
		if (zi->lame_timer < now) {
			ISC_LIST_UNLINK(entry->zoneinfo, zi, plink);
			free_adbzoneinfo(adb, &zi);
		}

		/*
		 * Order tests from least to most expensive.
		 */
		if (zi != NULL && !is_bad) {
			if (dns_name_equal(zone, &zi->zone))
				is_bad = ISC_TRUE;
		}

		zi = next_zi;
	}

	return (is_bad);
}

static void
copy_namehook_lists(dns_adb_t *adb, dns_adbfind_t *find, dns_name_t *zone,
		    dns_adbname_t *name, isc_stdtime_t now)
{
	dns_adbnamehook_t *namehook;
	dns_adbaddrinfo_t *addrinfo;
	dns_adbentry_t *entry;
	int bucket;

	bucket = DNS_ADB_INVALIDBUCKET;

	if (find->options & DNS_ADBFIND_INET) {
		namehook = ISC_LIST_HEAD(name->v4);
		while (namehook != NULL) {
			entry = namehook->entry;
			bucket = entry->lock_bucket;
			LOCK(&adb->entrylocks[bucket]);

			if (!FIND_RETURNLAME(find)
			    && entry_is_bad_for_zone(adb, entry, zone, now)) {
				find->options |= DNS_ADBFIND_LAMEPRUNED;
				goto nextv4;
			}
			addrinfo = new_adbaddrinfo(adb, entry, find->port);
			if (addrinfo == NULL) {
				find->partial_result |= DNS_ADBFIND_INET;
				goto out;
			}
			/*
			 * Found a valid entry.  Add it to the find's list.
			 */
			inc_entry_refcnt(adb, entry, ISC_FALSE);
			ISC_LIST_APPEND(find->list, addrinfo, publink);
			addrinfo = NULL;
		nextv4:
			UNLOCK(&adb->entrylocks[bucket]);
			bucket = DNS_ADB_INVALIDBUCKET;
			namehook = ISC_LIST_NEXT(namehook, plink);
		}
	}

	if (find->options & DNS_ADBFIND_INET6) {
		namehook = ISC_LIST_HEAD(name->v6);
		while (namehook != NULL) {
			entry = namehook->entry;
			bucket = entry->lock_bucket;
			LOCK(&adb->entrylocks[bucket]);

			if (entry_is_bad_for_zone(adb, entry, zone, now))
				goto nextv6;
			addrinfo = new_adbaddrinfo(adb, entry, find->port);
			if (addrinfo == NULL) {
				find->partial_result |= DNS_ADBFIND_INET6;
				goto out;
			}
			/*
			 * Found a valid entry.  Add it to the find's list.
			 */
			inc_entry_refcnt(adb, entry, ISC_FALSE);
			ISC_LIST_APPEND(find->list, addrinfo, publink);
			addrinfo = NULL;
		nextv6:
			UNLOCK(&adb->entrylocks[bucket]);
			bucket = DNS_ADB_INVALIDBUCKET;
			namehook = ISC_LIST_NEXT(namehook, plink);
		}
	}

 out:
	if (bucket != DNS_ADB_INVALIDBUCKET)
		UNLOCK(&adb->entrylocks[bucket]);
}

static void
shutdown_task(isc_task_t *task, isc_event_t *ev) {
	dns_adb_t *adb;

	UNUSED(task);

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

	/*
	 * Kill the timer, and then the ADB itself.  Note that this implies
	 * that this task was the one scheduled to get timer events.  If
	 * this is not true (and it is unfortunate there is no way to INSIST()
	 * this) badness will occur.
	 */
	LOCK(&adb->lock);
	isc_timer_detach(&adb->timer);
	UNLOCK(&adb->lock);
	isc_event_free(&ev);
	destroy(adb);
}

/*
 * Name bucket must be locked; adb may be locked; no other locks held.
 */
static isc_boolean_t
check_expire_name(dns_adbname_t **namep, isc_stdtime_t now) {
	dns_adbname_t *name;
	isc_result_t result = ISC_FALSE;

	INSIST(namep != NULL && DNS_ADBNAME_VALID(*namep));
	name = *namep;

	if (NAME_HAS_V4(name) || NAME_HAS_V6(name))
		return (result);
	if (NAME_FETCH(name))
		return (result);
	if (!EXPIRE_OK(name->expire_v4, now))
		return (result);
	if (!EXPIRE_OK(name->expire_v6, now))
		return (result);
	if (!EXPIRE_OK(name->expire_target, now))
		return (result);

	/*
	 * The name is empty.  Delete it.
	 */
	result = kill_name(&name, DNS_EVENT_ADBEXPIRED);
	*namep = NULL;

	/*
	 * Our caller, or one of its callers, will be calling check_exit() at
	 * some point, so we don't need to do it here.
	 */
	return (result);
}

/*
 * Entry bucket must be locked; adb may be locked; no other locks held.
 */
static isc_boolean_t
check_expire_entry(dns_adb_t *adb, dns_adbentry_t **entryp, isc_stdtime_t now)
{
	dns_adbentry_t *entry;
	isc_boolean_t expire;
	isc_boolean_t result = ISC_FALSE;

	INSIST(entryp != NULL && DNS_ADBENTRY_VALID(*entryp));
	entry = *entryp;

	if (entry->refcnt != 0)
		return (result);

	if (adb->overmem) {
		isc_uint32_t val;

		isc_random_get(&val);

		expire = ISC_TF((val % 4) == 0);
	} else
		expire = ISC_FALSE;

	if (entry->expires == 0 || (! expire && entry->expires > now))
		return (result);

	/*
	 * The entry is not in use.  Delete it.
	 */
	DP(DEF_LEVEL, "killing entry %p", entry);
	INSIST(ISC_LINK_LINKED(entry, plink));
	result = unlink_entry(adb, entry);
	free_adbentry(adb, &entry);
	if (result)
		dec_adb_irefcnt(adb);
	*entryp = NULL;
	return (result);
}

/*
 * ADB must be locked, and no other locks held.
 */
static isc_boolean_t
cleanup_names(dns_adb_t *adb, int bucket, isc_stdtime_t now) {
	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, adb->overmem);
		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;
	isc_interval_t interval;

	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.
	 */
	interval = adb->tick_interval;
	if (adb->overmem)
		isc_interval_set(&interval, 0, 1);
	(void)isc_timer_reset(adb->timer, isc_timertype_once, NULL,
			      &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);

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

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

	isc_mem_putanddetach(&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->task = NULL;
	adb->timer = NULL;
	adb->mctx = NULL;
	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;
	adb->overmem = ISC_FALSE;
	ISC_LIST_INIT(adb->whenshutdown);

	isc_mem_attach(mem, &adb->mctx);

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

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