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Merged
bdraco merged 1 commit into from
Jun 19, 2021
Merged

Switch to using DNSRRSet in RecordManager #735

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7 changes: 7 additions & 0 deletions zeroconf/_dns.py
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Original file line number Diff line number Diff line change
Expand Up @@ -423,3 +423,10 @@ def suppresses(self, record: DNSRecord) -> bool:
self._lookup = {record: record for record in self._records}
other = self._lookup.get(record)
return bool(other and other.ttl > (record.ttl / 2))

def __contains__(self, record: DNSRecord) -> bool:
"""Returns true if the rrset contains the record."""
if self._lookup is None:
# Build the hash table so we can lookup the record independent of the ttl
self._lookup = {record: record for record in self._records}
return record in self._lookup
56 changes: 32 additions & 24 deletions zeroconf/_handlers.py
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Expand Up @@ -311,42 +311,33 @@ def async_updates_from_response(self, msg: DNSIncoming) -> None:
other_adds: List[DNSRecord] = []
removes: List[DNSRecord] = []
now = msg.now
for record in msg.answers:

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

for record in msg.answers:
if record.unique: # https://tools.ietf.org/html/rfc6762#section-10.2
# rfc6762#section-10.2 para 2
# Since unique is set, all old records with that name, rrtype,
# and rrclass that were received more than one second ago are declared
# invalid, and marked to expire from the cache in one second.
for entry in self.cache.get_all_by_details(record.name, record.type, record.class_):
if entry == record:
updated = False
if record.created - entry.created > 1000 and entry not in msg.answers:
# Expire in 1s
entry.set_created_ttl(now, 1)

expired = record.is_expired(now)
unique_types.add((record.name, record.type, record.class_))

maybe_entry = self.cache.get(record)
if not expired:
if not record.is_expired(now):
if maybe_entry is not None:
maybe_entry.reset_ttl(record)
else:
if isinstance(record, DNSAddress):
address_adds.append(record)
else:
other_adds.append(record)
if updated:
updates.append(record)
updates.append(record)
# This is likely a goodbye since the record is
# expired and exists in the cache
elif maybe_entry is not None:
updates.append(record)
removes.append(record)

if not updates and not address_adds and not other_adds and not removes:
return
if unique_types:
self._async_mark_unique_cached_records_older_than_1s_to_expire(unique_types, msg.answers, now)

self.async_updates(now, updates)
if updates:
self.async_updates(now, updates)
# The cache adds must be processed AFTER we trigger
# the updates since we compare existing data
# with the new data and updating the cache
Expand All @@ -362,12 +353,29 @@ def async_updates_from_response(self, msg: DNSIncoming) -> None:
# zc.get_service_info will see the cached value
# but ONLY after all the record updates have been
# processsed.
self.cache.async_add_records(itertools.chain(address_adds, other_adds))
if other_adds or address_adds:
self.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.
self.cache.async_remove_records(removes)
self.async_updates_complete()
if removes:
self.cache.async_remove_records(removes)
if updates:
self.async_updates_complete()

def _async_mark_unique_cached_records_older_than_1s_to_expire(
self, unique_types: Set[Tuple[str, int, int]], answers: List[DNSRecord], now: float
) -> None:
# rfc6762#section-10.2 para 2
# Since unique is set, all old records with that name, rrtype,
# and rrclass that were received more than one second ago are declared
# invalid, and marked to expire from the cache in one second.
answers_rrset = DNSRRSet(answers)
for name, type_, class_ in unique_types:
for entry in self.cache.get_all_by_details(name, type_, class_):
if (now - entry.created > 1000) and entry not in answers_rrset:
# Expire in 1s
entry.set_created_ttl(now, 1)

def add_listener(
self, listener: RecordUpdateListener, question: Optional[Union[DNSQuestion, List[DNSQuestion]]]
Expand Down