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Merged
bdraco merged 5 commits into from
Aug 14, 2023
Merged

chore: split AsyncEngine into _engine.py #1218

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c841f01
chore: split AsyncEngine into _engine.py
bdraco Aug 14, 2023
1a41f66
chore: split AsyncEngine into _engine.py
bdraco Aug 14, 2023
28b8a15
chore: relo tests
bdraco Aug 14, 2023
04bb578
chore: update fixtures
bdraco Aug 14, 2023
ed2c2da
chore: update fixtures
bdraco Aug 14, 2023
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335 changes: 4 additions & 331 deletions src/zeroconf/_core.py
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Original file line number Diff line number Diff line change
Expand Up @@ -21,17 +21,15 @@
"""

import asyncio
import itertools
import logging
import random
import socket
import sys
import threading
from types import TracebackType # noqa # used in type hints
from typing import Any, Awaitable, Dict, List, Optional, Tuple, Type, Union, cast
from types import TracebackType
from typing import Awaitable, Dict, List, Optional, Tuple, Type, Union

from ._cache import DNSCache
from ._dns import DNSQuestion, DNSQuestionType
from ._engine import AsyncEngine, _WrappedTransport
from ._exceptions import NonUniqueNameException, NotRunningException
from ._handlers import (
MulticastOutgoingQueue,
Expand All @@ -48,7 +46,7 @@
from ._services.browser import ServiceBrowser
from ._services.info import ServiceInfo, instance_name_from_service_info
from ._services.registry import ServiceRegistry
from ._updates import RecordUpdate, RecordUpdateListener
from ._updates import RecordUpdateListener
from ._utils.asyncio import (
await_awaitable,
get_running_loop,
Expand All @@ -67,11 +65,9 @@
)
from ._utils.time import current_time_millis, millis_to_seconds
from .const import (
_CACHE_CLEANUP_INTERVAL,
_CHECK_TIME,
_CLASS_IN,
_CLASS_UNIQUE,
_DUPLICATE_PACKET_SUPPRESSION_INTERVAL,
_FLAGS_AA,
_FLAGS_QR_QUERY,
_FLAGS_QR_RESPONSE,
Expand All @@ -86,7 +82,6 @@
_UNREGISTER_TIME,
)

_TC_DELAY_RANDOM_INTERVAL = (400, 500)
# The maximum amont of time to delay a multicast
# response in order to aggregate answers
_AGGREGATION_DELAY = 500 # ms
Expand All @@ -102,331 +97,9 @@
# 3000ms
_PROTECTED_AGGREGATION_DELAY = 200 # ms

_CLOSE_TIMEOUT = 3000 # ms
_REGISTER_BROADCASTS = 3


class _WrappedTransport:
"""A wrapper for transports."""

__slots__ = (
'transport',
'is_ipv6',
'sock',
'fileno',
'sock_name',
)

def __init__(
self,
transport: asyncio.DatagramTransport,
is_ipv6: bool,
sock: socket.socket,
fileno: int,
sock_name: Any,
) -> None:
"""Initialize the wrapped transport.

These attributes are used when sending packets.
"""
self.transport = transport
self.is_ipv6 = is_ipv6
self.sock = sock
self.fileno = fileno
self.sock_name = sock_name


def _make_wrapped_transport(transport: asyncio.DatagramTransport) -> _WrappedTransport:
"""Make a wrapped transport."""
sock: socket.socket = transport.get_extra_info('socket')
return _WrappedTransport(
transport=transport,
is_ipv6=sock.family == socket.AF_INET6,
sock=sock,
fileno=sock.fileno(),
sock_name=sock.getsockname(),
)


class AsyncEngine:
"""An engine wraps sockets in the event loop."""

__slots__ = (
'loop',
'zc',
'protocols',
'readers',
'senders',
'running_event',
'_listen_socket',
'_respond_sockets',
'_cleanup_timer',
)

def __init__(
self,
zeroconf: 'Zeroconf',
listen_socket: Optional[socket.socket],
respond_sockets: List[socket.socket],
) -> None:
self.loop: Optional[asyncio.AbstractEventLoop] = None
self.zc = zeroconf
self.protocols: List[AsyncListener] = []
self.readers: List[_WrappedTransport] = []
self.senders: List[_WrappedTransport] = []
self.running_event: Optional[asyncio.Event] = None
self._listen_socket = listen_socket
self._respond_sockets = respond_sockets
self._cleanup_timer: Optional[asyncio.TimerHandle] = None

def setup(self, loop: asyncio.AbstractEventLoop, loop_thread_ready: Optional[threading.Event]) -> None:
"""Set up the instance."""
self.loop = loop
self.running_event = asyncio.Event()
self.loop.create_task(self._async_setup(loop_thread_ready))

async def _async_setup(self, loop_thread_ready: Optional[threading.Event]) -> None:
"""Set up the instance."""
assert self.loop is not None
self._cleanup_timer = self.loop.call_later(_CACHE_CLEANUP_INTERVAL, self._async_cache_cleanup)
await self._async_create_endpoints()
assert self.running_event is not None
self.running_event.set()
if loop_thread_ready:
loop_thread_ready.set()

async def _async_create_endpoints(self) -> None:
"""Create endpoints to send and receive."""
assert self.loop is not None
loop = self.loop
reader_sockets = []
sender_sockets = []
if self._listen_socket:
reader_sockets.append(self._listen_socket)
for s in self._respond_sockets:
if s not in reader_sockets:
reader_sockets.append(s)
sender_sockets.append(s)

for s in reader_sockets:
transport, protocol = await loop.create_datagram_endpoint(lambda: AsyncListener(self.zc), sock=s)
self.protocols.append(cast(AsyncListener, protocol))
self.readers.append(_make_wrapped_transport(cast(asyncio.DatagramTransport, transport)))
if s in sender_sockets:
self.senders.append(_make_wrapped_transport(cast(asyncio.DatagramTransport, transport)))

def _async_cache_cleanup(self) -> None:
"""Periodic cache cleanup."""
now = current_time_millis()
self.zc.question_history.async_expire(now)
self.zc.record_manager.async_updates(
now, [RecordUpdate(record, record) for record in self.zc.cache.async_expire(now)]
)
self.zc.record_manager.async_updates_complete(False)
assert self.loop is not None
self._cleanup_timer = self.loop.call_later(_CACHE_CLEANUP_INTERVAL, self._async_cache_cleanup)

async def _async_close(self) -> None:
"""Cancel and wait for the cleanup task to finish."""
self._async_shutdown()
await asyncio.sleep(0) # flush out any call soons
assert self._cleanup_timer is not None
self._cleanup_timer.cancel()

def _async_shutdown(self) -> None:
"""Shutdown transports and sockets."""
assert self.running_event is not None
self.running_event.clear()
for wrapped_transport in itertools.chain(self.senders, self.readers):
wrapped_transport.transport.close()

def close(self) -> None:
"""Close from sync context.

While it is not expected during normal operation,
this function may raise EventLoopBlocked if the underlying
call to `_async_close` cannot be completed.
"""
assert self.loop is not None
# Guard against Zeroconf.close() being called from the eventloop
if get_running_loop() == self.loop:
self._async_shutdown()
return
if not self.loop.is_running():
return
run_coro_with_timeout(self._async_close(), self.loop, _CLOSE_TIMEOUT)


class AsyncListener(asyncio.Protocol, QuietLogger):

"""A Listener is used by this module to listen on the multicast
group to which DNS messages are sent, allowing the implementation
to cache information as it arrives.

It requires registration with an Engine object in order to have
the read() method called when a socket is available for reading."""

__slots__ = ('zc', 'data', 'last_time', 'transport', 'sock_description', '_deferred', '_timers')

def __init__(self, zc: 'Zeroconf') -> None:
self.zc = zc
self.data: Optional[bytes] = None
self.last_time: float = 0
self.last_message: Optional[DNSIncoming] = None
self.transport: Optional[_WrappedTransport] = None
self.sock_description: Optional[str] = None
self._deferred: Dict[str, List[DNSIncoming]] = {}
self._timers: Dict[str, asyncio.TimerHandle] = {}
super().__init__()

def datagram_received(
self, data: bytes, addrs: Union[Tuple[str, int], Tuple[str, int, int, int]]
) -> None:
assert self.transport is not None
data_len = len(data)
debug = log.isEnabledFor(logging.DEBUG)

if data_len > _MAX_MSG_ABSOLUTE:
# Guard against oversized packets to ensure bad implementations cannot overwhelm
# the system.
if debug:
log.debug(
"Discarding incoming packet with length %s, which is larger "
"than the absolute maximum size of %s",
data_len,
_MAX_MSG_ABSOLUTE,
)
return

now = current_time_millis()
if (
self.data == data
and (now - _DUPLICATE_PACKET_SUPPRESSION_INTERVAL) < self.last_time
and self.last_message is not None
and not self.last_message.has_qu_question()
):
# Guard against duplicate packets
if debug:
log.debug(
'Ignoring duplicate message with no unicast questions received from %s [socket %s] (%d bytes) as [%r]',
addrs,
self.sock_description,
data_len,
data,
)
return

v6_flow_scope: Union[Tuple[()], Tuple[int, int]] = ()
if len(addrs) == 2:
# https://github.com/python/mypy/issues/1178
addr, port = addrs # type: ignore
scope = None
else:
# https://github.com/python/mypy/issues/1178
addr, port, flow, scope = addrs # type: ignore
if debug:
log.debug('IPv6 scope_id %d associated to the receiving interface', scope)
v6_flow_scope = (flow, scope)

msg = DNSIncoming(data, (addr, port), scope, now)
self.data = data
self.last_time = now
self.last_message = msg
if msg.valid:
if debug:
log.debug(
'Received from %r:%r [socket %s]: %r (%d bytes) as [%r]',
addr,
port,
self.sock_description,
msg,
data_len,
data,
)
else:
if debug:
log.debug(
'Received from %r:%r [socket %s]: (%d bytes) [%r]',
addr,
port,
self.sock_description,
data_len,
data,
)
return

if not msg.is_query():
self.zc.handle_response(msg)
return

self.handle_query_or_defer(msg, addr, port, self.transport, v6_flow_scope)

def handle_query_or_defer(
self,
msg: DNSIncoming,
addr: str,
port: int,
transport: _WrappedTransport,
v6_flow_scope: Union[Tuple[()], Tuple[int, int]] = (),
) -> None:
"""Deal with incoming query packets. Provides a response if
possible."""
if not msg.truncated:
self._respond_query(msg, addr, port, transport, v6_flow_scope)
return

deferred = self._deferred.setdefault(addr, [])
# If we get the same packet we ignore it
for incoming in reversed(deferred):
if incoming.data == msg.data:
return
deferred.append(msg)
delay = millis_to_seconds(random.randint(*_TC_DELAY_RANDOM_INTERVAL))
assert self.zc.loop is not None
self._cancel_any_timers_for_addr(addr)
self._timers[addr] = self.zc.loop.call_later(
delay, self._respond_query, None, addr, port, transport, v6_flow_scope
)

def _cancel_any_timers_for_addr(self, addr: str) -> None:
"""Cancel any future truncated packet timers for the address."""
if addr in self._timers:
self._timers.pop(addr).cancel()

def _respond_query(
self,
msg: Optional[DNSIncoming],
addr: str,
port: int,
transport: _WrappedTransport,
v6_flow_scope: Union[Tuple[()], Tuple[int, int]] = (),
) -> None:
"""Respond to a query and reassemble any truncated deferred packets."""
self._cancel_any_timers_for_addr(addr)
packets = self._deferred.pop(addr, [])
if msg:
packets.append(msg)

self.zc.handle_assembled_query(packets, addr, port, transport, v6_flow_scope)

def error_received(self, exc: Exception) -> None:
"""Likely socket closed or IPv6."""
# We preformat the message string with the socket as we want
# log_exception_once to log a warrning message once PER EACH
# different socket in case there are problems with multiple
# sockets
msg_str = f"Error with socket {self.sock_description}): %s"
self.log_exception_once(exc, msg_str, exc)

def connection_made(self, transport: asyncio.BaseTransport) -> None:
wrapped_transport = _make_wrapped_transport(cast(asyncio.DatagramTransport, transport))
self.transport = wrapped_transport
self.sock_description = f"{wrapped_transport.fileno} ({wrapped_transport.sock_name})"

def connection_lost(self, exc: Optional[Exception]) -> None:
"""Handle connection lost."""


def async_send_with_transport(
log_debug: bool,
transport: _WrappedTransport,
Expand Down
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