adb.c

bind 9.3结合mysql数据库

			isc_sockaddr_fromin(&sockaddr, &ina, 0);
		} else {
			INSIST(rdata.length == 16);
			memcpy(in6a.s6_addr, rdata.data, 16);
			isc_sockaddr_fromin6(&sockaddr, &in6a, 0);
		}

		INSIST(nh == NULL);
		nh = new_adbnamehook(adb, NULL);
		if (nh == NULL) {
			adbname->partial_result |= findoptions;
			result = ISC_R_NOMEMORY;
			goto fail;
		}

		foundentry = find_entry_and_lock(adb, &sockaddr, &addr_bucket);
		if (foundentry == NULL) {
			dns_adbentry_t *entry;

			entry = new_adbentry(adb);
			if (entry == NULL) {
				adbname->partial_result |= findoptions;
				result = ISC_R_NOMEMORY;
				goto fail;
			}

			entry->sockaddr = sockaddr;
			entry->refcnt = 1;

			nh->entry = entry;

			link_entry(adb, addr_bucket, entry);
		} else {
			for (anh = ISC_LIST_HEAD(adbname->v4);
			     anh != NULL;
			     anh = ISC_LIST_NEXT(anh, plink))
				if (anh->entry == foundentry)
					break;
			if (anh == NULL) {
				foundentry->refcnt++;
				nh->entry = foundentry;
			} else
				free_adbnamehook(adb, &nh);
		}

		new_addresses_added = ISC_TRUE;
		if (nh != NULL) {
			if (rdtype == dns_rdatatype_a)
				ISC_LIST_APPEND(adbname->v4, nh, plink);
			else
				ISC_LIST_APPEND(adbname->v6, nh, plink);
		}
		nh = NULL;
		result = dns_rdataset_next(rdataset);
	}

 fail:
	if (nh != NULL)
		free_adbnamehook(adb, &nh);

	if (addr_bucket != DNS_ADB_INVALIDBUCKET)
		UNLOCK(&adb->entrylocks[addr_bucket]);

	if (rdataset->trust == dns_trust_glue ||
	    rdataset->trust == dns_trust_additional)
		rdataset->ttl = ADB_CACHE_MINIMUM;
	else
		rdataset->ttl = ttlclamp(rdataset->ttl);

	if (rdtype == dns_rdatatype_a) {
		DP(NCACHE_LEVEL, "expire_v4 set to MIN(%u,%u) import_rdataset",
		   adbname->expire_v4, now + rdataset->ttl);
		adbname->expire_v4 = ISC_MIN(adbname->expire_v4,
					     now + rdataset->ttl);
	} else {
		DP(NCACHE_LEVEL, "expire_v6 set to MIN(%u,%u) import_rdataset",
		   adbname->expire_v6, now + rdataset->ttl);
		adbname->expire_v6 = ISC_MIN(adbname->expire_v6,
					     now + rdataset->ttl);
	}

	if (new_addresses_added) {
		/*
		 * Lie a little here.  This is more or less so code that cares
		 * can find out if any new information was added or not.
		 */
		return (ISC_R_SUCCESS);
	}

	return (result);
}

/*
 * Requires the name's bucket be locked.
 */
static isc_boolean_t
kill_name(dns_adbname_t **n, isc_eventtype_t ev) {
	dns_adbname_t *name;
	isc_boolean_t result = ISC_FALSE;
	isc_boolean_t result4, result6;
	dns_adb_t *adb;

	INSIST(n != NULL);
	name = *n;
	*n = NULL;
	INSIST(DNS_ADBNAME_VALID(name));
	adb = name->adb;
	INSIST(DNS_ADB_VALID(adb));

	DP(DEF_LEVEL, "killing name %p", name);

	/*
	 * If we're dead already, just check to see if we should go
	 * away now or not.
	 */
	if (NAME_DEAD(name) && !NAME_FETCH(name)) {
		result = unlink_name(adb, name);
		free_adbname(adb, &name);
		if (result)
			result = dec_adb_irefcnt(adb);
		return (result);
	}

	/*
	 * Clean up the name's various lists.  These two are destructive
	 * in that they will always empty the list.
	 */
	clean_finds_at_name(name, ev, DNS_ADBFIND_ADDRESSMASK);
	result4 = clean_namehooks(adb, &name->v4);
	result6 = clean_namehooks(adb, &name->v6);
	clean_target(adb, &name->target);
	result = ISC_TF(result4 || result6);

	/*
	 * If fetches are running, cancel them.  If none are running, we can
	 * just kill the name here.
	 */
	if (!NAME_FETCH(name)) {
		INSIST(result == ISC_FALSE);
		result = unlink_name(adb, name);
		free_adbname(adb, &name);
		if (result)
			result = dec_adb_irefcnt(adb);
	} else {
		name->flags |= NAME_IS_DEAD;
		cancel_fetches_at_name(name);
	}
	return (result);
}

/*
 * Requires the name's bucket be locked and no entry buckets be locked.
 */
static isc_boolean_t
check_expire_namehooks(dns_adbname_t *name, isc_stdtime_t now,
		       isc_boolean_t overmem)
{
	dns_adb_t *adb;
	isc_boolean_t expire;
	isc_boolean_t result4 = ISC_FALSE;
	isc_boolean_t result6 = ISC_FALSE;

	INSIST(DNS_ADBNAME_VALID(name));
	adb = name->adb;
	INSIST(DNS_ADB_VALID(adb));

	if (overmem) {
		isc_uint32_t val;

		isc_random_get(&val);

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

	/*
	 * Check to see if we need to remove the v4 addresses
	 */
	if (!NAME_FETCH_V4(name) &&
	    (expire || EXPIRE_OK(name->expire_v4, now))) {
		if (NAME_HAS_V4(name)) {
			DP(DEF_LEVEL, "expiring v4 for name %p", name);
			result4 = clean_namehooks(adb, &name->v4);
			name->partial_result &= ~DNS_ADBFIND_INET;
		}
		name->expire_v4 = INT_MAX;
		name->fetch_err = FIND_ERR_UNEXPECTED;
	}

	/*
	 * Check to see if we need to remove the v6 addresses
	 */
	if (!NAME_FETCH_V6(name) &&
	    (expire || EXPIRE_OK(name->expire_v6, now))) {
		if (NAME_HAS_V6(name)) {
			DP(DEF_LEVEL, "expiring v6 for name %p", name);
			result6 = clean_namehooks(adb, &name->v6);
			name->partial_result &= ~DNS_ADBFIND_INET6;
		}
		name->expire_v6 = INT_MAX;
		name->fetch6_err = FIND_ERR_UNEXPECTED;
	}

	/*
	 * Check to see if we need to remove the alias target.
	 */
	if (expire || EXPIRE_OK(name->expire_target, now)) {
		clean_target(adb, &name->target);
		name->expire_target = INT_MAX;
	}
	return (ISC_TF(result4 || result6));
}

/*
 * Requires the name's bucket be locked.
 */
static inline void
link_name(dns_adb_t *adb, int bucket, dns_adbname_t *name) {
	INSIST(name->lock_bucket == DNS_ADB_INVALIDBUCKET);

	ISC_LIST_PREPEND(adb->names[bucket], name, plink);
	name->lock_bucket = bucket;
	adb->name_refcnt[bucket]++;
}

/*
 * Requires the name's bucket be locked.
 */
static inline isc_boolean_t
unlink_name(dns_adb_t *adb, dns_adbname_t *name) {
	int bucket;
	isc_boolean_t result = ISC_FALSE;

	bucket = name->lock_bucket;
	INSIST(bucket != DNS_ADB_INVALIDBUCKET);

	ISC_LIST_UNLINK(adb->names[bucket], name, plink);
	name->lock_bucket = DNS_ADB_INVALIDBUCKET;
	INSIST(adb->name_refcnt[bucket] > 0);
	adb->name_refcnt[bucket]--;
	if (adb->name_sd[bucket] && adb->name_refcnt[bucket] == 0)
		result = ISC_TRUE;
	return (result);
}

/*
 * Requires the entry's bucket be locked.
 */
static inline void
link_entry(dns_adb_t *adb, int bucket, dns_adbentry_t *entry) {
	ISC_LIST_PREPEND(adb->entries[bucket], entry, plink);
	entry->lock_bucket = bucket;
	adb->entry_refcnt[bucket]++;
}

/*
 * Requires the entry's bucket be locked.
 */
static inline isc_boolean_t
unlink_entry(dns_adb_t *adb, dns_adbentry_t *entry) {
	int bucket;
	isc_boolean_t result = ISC_FALSE;

	bucket = entry->lock_bucket;
	INSIST(bucket != DNS_ADB_INVALIDBUCKET);

	ISC_LIST_UNLINK(adb->entries[bucket], entry, plink);
	entry->lock_bucket = DNS_ADB_INVALIDBUCKET;
	INSIST(adb->entry_refcnt[bucket] > 0);
	adb->entry_refcnt[bucket]--;
	if (adb->entry_sd[bucket] && adb->entry_refcnt[bucket] == 0)
		result = ISC_TRUE;
	return (result);
}

static inline void
violate_locking_hierarchy(isc_mutex_t *have, isc_mutex_t *want) {
	if (isc_mutex_trylock(want) != ISC_R_SUCCESS) {
		UNLOCK(have);
		LOCK(want);
		LOCK(have);
	}
}

/*
 * The ADB _MUST_ be locked before calling.  Also, exit conditions must be
 * checked after calling this function.
 */
static isc_boolean_t
shutdown_names(dns_adb_t *adb) {
	int bucket;
	isc_boolean_t result = ISC_FALSE;
	dns_adbname_t *name;
	dns_adbname_t *next_name;

	for (bucket = 0; bucket < NBUCKETS; bucket++) {
		LOCK(&adb->namelocks[bucket]);
		adb->name_sd[bucket] = ISC_TRUE;

		name = ISC_LIST_HEAD(adb->names[bucket]);
		if (name == NULL) {
			/*
			 * This bucket has no names.  We must decrement the
			 * irefcnt ourselves, since it will not be
			 * automatically triggered by a name being unlinked.
			 */
			INSIST(result == ISC_FALSE);
			result = dec_adb_irefcnt(adb);
		} else {
			/*
			 * Run through the list.  For each name, clean up finds
			 * found there, and cancel any fetches running.  When
			 * all the fetches are canceled, the name will destroy
			 * itself.
			 */
			while (name != NULL) {
				next_name = ISC_LIST_NEXT(name, plink);
				INSIST(result == ISC_FALSE);
				result = kill_name(&name,
						   DNS_EVENT_ADBSHUTDOWN);
				name = next_name;
			}
		}

		UNLOCK(&adb->namelocks[bucket]);
	}
	return (result);
}

/*
 * The ADB _MUST_ be locked before calling.  Also, exit conditions must be
 * checked after calling this function.
 */
static isc_boolean_t
shutdown_entries(dns_adb_t *adb) {
	int bucket;
	isc_boolean_t result = ISC_FALSE;
	dns_adbentry_t *entry;
	dns_adbentry_t *next_entry;

	for (bucket = 0; bucket < NBUCKETS; bucket++) {
		LOCK(&adb->entrylocks[bucket]);
		adb->entry_sd[bucket] = ISC_TRUE;

		entry = ISC_LIST_HEAD(adb->entries[bucket]);
		if (entry == NULL) {
			/*
			 * This bucket has no entries.  We must decrement the
			 * irefcnt ourselves, since it will not be
			 * automatically triggered by an entry being unlinked.
			 */
			result = dec_adb_irefcnt(adb);
		} else {
			/*
			 * Run through the list.  Cleanup any entries not
			 * associated with names, and which are not in use.
			 */
			while (entry != NULL) {
				next_entry = ISC_LIST_NEXT(entry, plink);
				if (entry->refcnt == 0 &&
				    entry->expires != 0) {
					result = unlink_entry(adb, entry);
					free_adbentry(adb, &entry);
					if (result)
						result = dec_adb_irefcnt(adb);
				}
				entry = next_entry;
			}
		}

		UNLOCK(&adb->entrylocks[bucket]);
	}
	return (result);
}

/*
 * Name bucket must be locked
 */
static void
cancel_fetches_at_name(dns_adbname_t *name) {
	if (NAME_FETCH_A(name))
	    dns_resolver_cancelfetch(name->fetch_a->fetch);

	if (NAME_FETCH_AAAA(name))
	    dns_resolver_cancelfetch(name->fetch_aaaa->fetch);
}

/*
 * Assumes the name bucket is locked.
 */
static isc_boolean_t
clean_namehooks(dns_adb_t *adb, dns_adbnamehooklist_t *namehooks) {
	dns_adbentry_t *entry;
	dns_adbnamehook_t *namehook;
	int addr_bucket;
	isc_boolean_t result = ISC_FALSE;

	addr_bucket = DNS_ADB_INVALIDBUCKET;
	namehook = ISC_LIST_HEAD(*namehooks);
	while (namehook != NULL) {
		INSIST(DNS_ADBNAMEHOOK_VALID(namehook));

		/*
		 * Clean up the entry if needed.
		 */
		entry = namehook->entry;
		if (entry != NULL) {
			INSIST(DNS_ADBENTRY_VALID(entry));

			if (addr_bucket != entry->lock_bucket) {
				if (addr_bucket != DNS_ADB_INVALIDBUCKET)
					UNLOCK(&adb->entrylocks[addr_bucket]);
				addr_bucket = entry->lock_bucket;
				LOCK(&adb->entrylocks[addr_bucket]);
			}

			result = dec_entry_refcnt(adb, entry, ISC_FALSE);
		}

		/*
		 * Free the namehook
		 */
		namehook->entry = NULL;
		ISC_LIST_UNLINK(*namehooks, namehook, plink);
		free_adbnamehook(adb, &namehook);

		namehook = ISC_LIST_HEAD(*namehooks);
	}

	if (addr_bucket != DNS_ADB_INVALIDBUCKET)
		UNLOCK(&adb->entrylocks[addr_bucket]);
	return (result);
}

static void
clean_target(dns_adb_t *adb, dns_name_t *target) {
	if (dns_name_countlabels(target) > 0) {
		dns_name_free(target, adb->mctx);
		dns_name_init(target, NULL);
	}
}

static isc_result_t
set_target(dns_adb_t *adb, dns_name_t *name, dns_name_t *fname,
	   dns_rdataset_t *rdataset, dns_name_t *target)
{
	isc_result_t result;
	dns_namereln_t namereln;
	unsigned int nlabels;
	int order;
	dns_rdata_t rdata = DNS_RDATA_INIT;
	dns_fixedname_t fixed1, fixed2;
	dns_name_t *prefix, *new_target;

	REQUIRE(dns_name_countlabels(target) == 0);

	if (rdataset->type == dns_rdatatype_cname) {
		dns_rdata_cname_t cname;

		/*
		 * Copy the CNAME's target into the target name.
		 */
		result = dns_rdataset_first(rdataset);
		if (result != ISC_R_SUCCESS)
			return (result);
		dns_rdataset_current(rdataset, &rdata);
		result = dns_rdata_tostruct(&rdata, &cname, NULL);
		if (result != ISC_R_SUCCESS)
			return (result);
		result = dns_name_dup(&cname.cname, adb->mctx, target);
		dns_rdata_freestruct(&cname);
		if (result != ISC_R_SUCCESS)
			return (result);
	} else {
		dns_rdata_dname_t dname;

		INSIST(rdataset->type == dns_rdatatype_dname);
		namereln = dns_name_fullcompare(name, fname, &order, &nlabels);
		INSIST(namereln == dns_namereln_subdomain);
		/*
		 * Get the target name of the DNAME.
		 */
		result = dns_rdataset_first(rdataset);
		if (result != ISC_R_SUCCESS)
			return (result);
		dns_rdataset_current(rdataset, &rdata);
		result = dns_rdata_tostruct(&rdata, &dname, NULL);
		if (result != ISC_R_SUCCESS)
			return (result);
		/*
		 * Construct the new target name.
		 */
		dns_fixedname_init(&fixed1);
		prefix = dns_fixedname_name(&fixed1);
		dns_fixedname_init(&fixed2);
		new_target = dns_fixedname_name(&fixed2);
		dns_name_split(name, nlabels, prefix, NULL);
		result = dns_name_concatenate(prefix, &dname.dname, new_target,
					      NULL);
		dns_rdata_freestruct(&dname);
		if (result != ISC_R_SUCCESS)
			return (result);
		result = dns_name_dup(new_target, adb->mctx, target);
		if (result != ISC_R_SUCCESS)
			return (result);
	}

	return (ISC_R_SUCCESS);
}

/*
 * Assumes nothing is locked, since this is called by the client.