Skip to content

Handle duplicate goodbye answers in the same packet #928

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
bdraco merged 3 commits into from
Jul 28, 2021
Merged

Handle duplicate goodbye answers in the same packet #928

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
fb529bc
Handle duplicate removes
bdraco Jul 27, 2021
71c410e
add test for duplicate answers
bdraco Jul 28, 2021
3ed397b
cover
bdraco Jul 28, 2021
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
32 changes: 32 additions & 0 deletions tests/test_handlers.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1122,3 +1122,35 @@ async def test_guard_against_low_ptr_ttl():
assert incoming_answer_normal.ttl == const._DNS_OTHER_TTL
assert zc.cache.async_get_unique(good_bye_answer) is None
await aiozc.async_close()


@pytest.mark.asyncio
async def test_duplicate_goodbye_answers_in_packet():
"""Ensure we do not throw an exception when there are duplicate goodbye records in a packet."""
aiozc = AsyncZeroconf(interfaces=['127.0.0.1'])
zc = aiozc.zeroconf
answer_with_normal_ttl = r.DNSPointer(
"myservicelow_tcp._tcp.local.",
const._TYPE_PTR,
const._CLASS_IN | const._CLASS_UNIQUE,
const._DNS_OTHER_TTL,
'host.local.',
)
good_bye_answer = r.DNSPointer(
"myservicelow_tcp._tcp.local.",
const._TYPE_PTR,
const._CLASS_IN | const._CLASS_UNIQUE,
0,
'host.local.',
)
response = r.DNSOutgoing(const._FLAGS_QR_RESPONSE)
response.add_answer_at_time(answer_with_normal_ttl, 0)
incoming = r.DNSIncoming(response.packets()[0])
zc.record_manager.async_updates_from_response(incoming)

response = r.DNSOutgoing(const._FLAGS_QR_RESPONSE)
response.add_answer_at_time(good_bye_answer, 0)
response.add_answer_at_time(good_bye_answer, 0)
incoming = r.DNSIncoming(response.packets()[0])
zc.record_manager.async_updates_from_response(incoming)
await aiozc.async_close()
4 changes: 2 additions & 2 deletions zeroconf/_handlers.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -331,7 +331,7 @@ def async_updates_from_response(self, msg: DNSIncoming) -> None:
updates: List[RecordUpdate] = []
address_adds: List[DNSAddress] = []
other_adds: List[DNSRecord] = []
removes: List[DNSRecord] = []
removes: Set[DNSRecord] = set()
now = msg.now
unique_types: Set[Tuple[str, int, int]] = set()

Expand All @@ -355,7 +355,7 @@ def async_updates_from_response(self, msg: DNSIncoming) -> None:
# expired and exists in the cache
elif maybe_entry is not None:
updates.append(RecordUpdate(record, maybe_entry))
removes.append(record)
removes.add(record)

if unique_types:
self._async_mark_unique_cached_records_older_than_1s_to_expire(unique_types, msg.answers, now)
Expand Down