Skip to content

New ServiceBrowsers now request QU in the first outgoing when unspecified #812

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 2 commits into from
Jun 22, 2021
Merged

New ServiceBrowsers now request QU in the first outgoing when unspecified #812

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
c4fe8f4
New ServiceBrowsers now request QU in the first outgoing when unspeci…
bdraco Jun 22, 2021
39ddc4b
reduce delay for PyPy
bdraco Jun 22, 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
19 changes: 12 additions & 7 deletions tests/services/test_browser.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -544,19 +544,23 @@ def on_service_state_change(zeroconf, service_type, state_change, name):
zeroconf_browser.close()


def test_asking_default_is_asking_qm_questions():
"""Verify the service browser can ask QU questions."""
def test_asking_default_is_asking_qm_questions_after_the_first_qu():
"""Verify the service browser's first question is QU and subsequent ones are QM questions."""
type_ = "_quservice._tcp.local."
zeroconf_browser = Zeroconf(interfaces=['127.0.0.1'])

# we are going to patch the zeroconf send to check query transmission
old_send = zeroconf_browser.async_send

first_outgoing = None
second_outgoing = None

def send(out, addr=const._MDNS_ADDR, port=const._MDNS_PORT):
"""Sends an outgoing packet."""
nonlocal first_outgoing
nonlocal second_outgoing
if first_outgoing is not None and second_outgoing is None:
second_outgoing = out
if first_outgoing is None:
first_outgoing = out
old_send(out, addr=addr, port=port)
Expand All @@ -567,10 +571,11 @@ def send(out, addr=const._MDNS_ADDR, port=const._MDNS_PORT):
def on_service_state_change(zeroconf, service_type, state_change, name):
pass

browser = ServiceBrowser(zeroconf_browser, type_, [on_service_state_change])
time.sleep(millis_to_seconds(_services_browser._FIRST_QUERY_DELAY_RANDOM_INTERVAL[1] + 5))
browser = ServiceBrowser(zeroconf_browser, type_, [on_service_state_change], delay=5)
time.sleep(millis_to_seconds(_services_browser._FIRST_QUERY_DELAY_RANDOM_INTERVAL[1] + 120 + 5))
try:
assert first_outgoing.questions[0].unicast == False
assert first_outgoing.questions[0].unicast == True
assert second_outgoing.questions[0].unicast == False
finally:
browser.cancel()
zeroconf_browser.close()
Expand Down Expand Up @@ -1016,7 +1021,7 @@ async def test_generate_service_query_suppress_duplicate_questions():
aiozc = AsyncZeroconf(interfaces=['127.0.0.1'])
zc = aiozc.zeroconf
now = current_time_millis()
name = "_hap._tcp.local."
name = "_suppresstest._tcp.local."
question = r.DNSQuestion(name, const._TYPE_PTR, const._CLASS_IN)
answer = r.DNSPointer(
name,
Expand Down Expand Up @@ -1048,7 +1053,7 @@ async def test_generate_service_query_suppress_duplicate_questions():
outs = _services_browser.generate_service_query(zc, now, [name], multicast=False)
assert outs

zc.question_history.async_expire(now + 1000)
zc.question_history.async_expire(now + 2000)
# No suppression after clearing the history
outs = _services_browser.generate_service_query(zc, now, [name], multicast=True)
assert outs
Expand Down
26 changes: 19 additions & 7 deletions zeroconf/_services/browser.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -146,11 +146,14 @@ def generate_service_query(
for record in zc.cache.get_all_by_details(type_, _TYPE_PTR, _CLASS_IN)
if not record.is_stale(now)
)
if multicast and zc.question_history.suppresses(question, now, cast(Set[DNSRecord], known_answers)):
if not qu_question and zc.question_history.suppresses(
question, now, cast(Set[DNSRecord], known_answers)
):
log.debug("Asking %s was suppressed by the question history", question)
continue
questions_with_known_answers[question] = known_answers
zc.question_history.add_question_at_time(question, now, cast(Set[DNSRecord], known_answers))
if not qu_question:
zc.question_history.add_question_at_time(question, now, cast(Set[DNSRecord], known_answers))

return _group_ptr_queries_with_known_answers(now, multicast, questions_with_known_answers)

Expand Down Expand Up @@ -379,7 +382,7 @@ def _async_cancel(self) -> None:
self.done = True
self.zc.async_remove_listener(self)

def generate_ready_queries(self) -> List[DNSOutgoing]:
def _generate_ready_queries(self, first_request: bool) -> List[DNSOutgoing]:
"""Generate the service browser query for any type that is due."""
now = current_time_millis()
if self._millis_to_wait(current_time_millis()):
Expand All @@ -395,7 +398,13 @@ def generate_ready_queries(self) -> List[DNSOutgoing]:
self._next_time[type_] = now + self._delay[type_]
self._delay[type_] = min(_BROWSER_BACKOFF_LIMIT * 1000, self._delay[type_] * 2)

return generate_service_query(self.zc, now, ready_types, self.multicast, self.question_type)
# If they did not specify and this is the first request, ask QU questions
# https://datatracker.ietf.org/doc/html/rfc6762#section-5.4 since we are
# just starting up and we know our cache is likely empty. This ensures
# the next outgoing will be sent with the known answers list.
question_type = DNSQuestionType.QU if not self.question_type and first_request else self.question_type

return generate_service_query(self.zc, now, ready_types, self.multicast, question_type)

def _millis_to_wait(self, now: float) -> Optional[float]:
"""Returns the number of milliseconds to wait for the next event."""
Expand All @@ -406,14 +415,17 @@ def _millis_to_wait(self, now: float) -> Optional[float]:
async def async_browser_task(self) -> None:
"""Run the browser task."""
await self.zc.async_wait_for_start()
first_request = True
while True:
timeout = self._millis_to_wait(current_time_millis())
if timeout:
await self.zc.async_wait(timeout)

outs = self.generate_ready_queries()
for out in outs:
self.zc.async_send(out, addr=self.addr, port=self.port)
outs = self._generate_ready_queries(first_request)
if outs:
first_request = False
for out in outs:
self.zc.async_send(out, addr=self.addr, port=self.port)

async def _async_cancel_browser(self) -> None:
"""Cancel the browser."""
Expand Down