removes: Set[DNSRecord] = set()

now = msg.now

unique_types: Set[Tuple[str, int, int]] = set()

cache = self.cache

for record in msg.answers:

# Protect zeroconf from records that can cause denial of service.

# ServiceBrowsers generating excessive queries refresh queries.

# Apple uses a 15s minimum TTL, however we do not have the same

# level of rate limit and safe guards so we use 1/4 of the recommended value.

if record.ttl and record.type == _TYPE_PTR and record.ttl < _DNS_PTR_MIN_TTL:

record_type = record.type

record_ttl = record.ttl

if record_ttl and record_type == _TYPE_PTR and record_ttl < _DNS_PTR_MIN_TTL:

log.debug(

"Increasing effective ttl of %s to minimum of %s to protect against excessive refreshes.",

record,

record.set_created_ttl(record.created, _DNS_PTR_MIN_TTL)

if record.unique: # https://tools.ietf.org/html/rfc6762#section-10.2

unique_types.add((record.name, record.type, record.class_))

unique_types.add((record.name, record_type, record.class_))

if TYPE_CHECKING:

record = cast(_UniqueRecordsType, record)

maybe_entry = self.cache.async_get_unique(record)

maybe_entry = cache.async_get_unique(record)

if not record.is_expired(now):

if maybe_entry is not None:

maybe_entry.reset_ttl(record)

removes.add(record)

if unique_types:

self.cache.async_mark_unique_records_older_than_1s_to_expire(unique_types, msg.answers, now)

cache.async_mark_unique_records_older_than_1s_to_expire(unique_types, msg.answers, now)

if updates:

self.async_updates(now, updates)

# processsed.

new = False

if other_adds or address_adds:

new = self.cache.async_add_records(itertools.chain(address_adds, other_adds))

new = cache.async_add_records(itertools.chain(address_adds, other_adds))

# Removes are processed last since

# ServiceInfo could generate an un-needed query

# because the data was not yet populated.

if removes:

self.cache.async_remove_records(removes)

cache.async_remove_records(removes)

if updates:

self.async_updates_complete(new)