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Break apart Zeroconf.handle_query to reduce branching #462

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Merged
bdraco merged 1 commit into from
Jun 6, 2021
Merged

Break apart Zeroconf.handle_query to reduce branching #462

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100 changes: 57 additions & 43 deletions zeroconf/__init__.py
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Original file line number Diff line number Diff line change
Expand Up @@ -2947,9 +2947,59 @@ def handle_response(self, msg: DNSIncoming) -> None: # pylint: disable=too-many
for record in removes:
self.cache.remove(record)

def handle_query( # pylint: disable=too-many-branches
self, msg: DNSIncoming, addr: Optional[str], port: int
) -> None:
def _answer_service_type_enumeration_query(self, msg: DNSIncoming, out: DNSOutgoing) -> None:
"""Provide an answer to a service type enumeration query.

https://datatracker.ietf.org/doc/html/rfc6763#section-9
"""
for stype in self.registry.get_types():
out.add_answer(
msg,
DNSPointer(
_SERVICE_TYPE_ENUMERATION_NAME,
_TYPE_PTR,
_CLASS_IN,
_DNS_OTHER_TTL,
stype,
),
)

def _answer_ptr_query(self, msg: DNSIncoming, out: DNSOutgoing, question: DNSQuestion) -> None:
"""Answer a PTR query."""
for service in self.registry.get_infos_type(question.name):
out.add_answer(msg, service.dns_pointer())
# Add recommended additional answers according to
# https://tools.ietf.org/html/rfc6763#section-12.1.
out.add_additional_answer(service.dns_service())
out.add_additional_answer(service.dns_text())
for dns_address in service.dns_addresses():
out.add_additional_answer(dns_address)

def _answer_non_ptr_query(self, msg: DNSIncoming, out: DNSOutgoing, question: DNSQuestion) -> None:
"""Answer a query any query other then PTR.

Add answer(s) for A, AAAA, SRV, or TXT queries.
"""
name_to_find = question.name.lower()
# Answer A record queries for any service addresses we know
if question.type in (_TYPE_A, _TYPE_ANY):
for service in self.registry.get_infos_server(name_to_find):
for dns_address in service.dns_addresses():
out.add_answer(msg, dns_address)

service = self.registry.get_info_name(name_to_find) # type: ignore
if service is None:
return

if question.type in (_TYPE_SRV, _TYPE_ANY):
out.add_answer(msg, service.dns_service())
if question.type in (_TYPE_TXT, _TYPE_ANY):
out.add_answer(msg, service.dns_text())
if question.type == _TYPE_SRV:
for dns_address in service.dns_addresses():
out.add_additional_answer(dns_address)

def handle_query(self, msg: DNSIncoming, addr: Optional[str], port: int) -> None:
"""Deal with incoming query packets. Provides a response if
possible."""
# Support unicast client responses
Expand All @@ -2964,48 +3014,12 @@ def handle_query( # pylint: disable=too-many-branches
for question in msg.questions:
if question.type == _TYPE_PTR:
if question.name == _SERVICE_TYPE_ENUMERATION_NAME:
for stype in self.registry.get_types():
out.add_answer(
msg,
DNSPointer(
_SERVICE_TYPE_ENUMERATION_NAME,
_TYPE_PTR,
_CLASS_IN,
_DNS_OTHER_TTL,
stype,
),
)
continue

for service in self.registry.get_infos_type(question.name):
out.add_answer(msg, service.dns_pointer())
# Add recommended additional answers according to
# https://tools.ietf.org/html/rfc6763#section-12.1.
out.add_additional_answer(service.dns_service())
out.add_additional_answer(service.dns_text())
for dns_address in service.dns_addresses():
out.add_additional_answer(dns_address)

continue

name_to_find = question.name.lower()
# Answer A record queries for any service addresses we know
if question.type in (_TYPE_A, _TYPE_ANY):
for service in self.registry.get_infos_server(name_to_find):
for dns_address in service.dns_addresses():
out.add_answer(msg, dns_address)

service = self.registry.get_info_name(name_to_find) # type: ignore
if service is None:
self._answer_service_type_enumeration_query(msg, out)
else:
self._answer_ptr_query(msg, out, question)
continue

if question.type in (_TYPE_SRV, _TYPE_ANY):
out.add_answer(msg, service.dns_service())
if question.type in (_TYPE_TXT, _TYPE_ANY):
out.add_answer(msg, service.dns_text())
if question.type == _TYPE_SRV:
for dns_address in service.dns_addresses():
out.add_additional_answer(dns_address)
self._answer_non_ptr_query(msg, out, question)

if out is not None and out.answers:
out.id = msg.id
Expand Down