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chore: split _engine.py into _transport.py and _listener.py #1222

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Merged
bdraco merged 4 commits into from
Aug 14, 2023
Merged

chore: split _engine.py into _transport.py and _listener.py #1222

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5f87045
chore: split _engine.py into _transport.py and _listener.py
bdraco Aug 14, 2023
063b0d2
chore: split _engine.py into _transport.py and _listener.py
bdraco Aug 14, 2023
770a3c4
chore: split tests
bdraco Aug 14, 2023
1088a1a
chore: fix patch target
bdraco Aug 14, 2023
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3 changes: 2 additions & 1 deletion src/zeroconf/_core.py
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Original file line number Diff line number Diff line change
Expand Up @@ -29,7 +29,7 @@

from ._cache import DNSCache
from ._dns import DNSQuestion, DNSQuestionType
from ._engine import AsyncEngine, _WrappedTransport
from ._engine import AsyncEngine
from ._exceptions import NonUniqueNameException, NotRunningException
from ._handlers import (
MulticastOutgoingQueue,
Expand All @@ -46,6 +46,7 @@
from ._services.browser import ServiceBrowser
from ._services.info import ServiceInfo, instance_name_from_service_info
from ._services.registry import ServiceRegistry
from ._transport import _WrappedTransport
from ._updates import RecordUpdateListener
from ._utils.asyncio import (
await_awaitable,
Expand Down
243 changes: 8 additions & 235 deletions src/zeroconf/_engine.py
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Original file line number Diff line number Diff line change
Expand Up @@ -22,71 +22,23 @@

import asyncio
import itertools
import logging
import random
import socket
import threading
from typing import TYPE_CHECKING, Any, Dict, List, Optional, Tuple, Union, cast
from typing import TYPE_CHECKING, List, Optional, cast

from ._logger import QuietLogger, log
from ._protocol.incoming import DNSIncoming
from ._updates import RecordUpdate
from ._utils.asyncio import get_running_loop, run_coro_with_timeout
from ._utils.time import current_time_millis, millis_to_seconds
from .const import (
_CACHE_CLEANUP_INTERVAL,
_DUPLICATE_PACKET_SUPPRESSION_INTERVAL,
_MAX_MSG_ABSOLUTE,
)
from ._utils.time import current_time_millis
from .const import _CACHE_CLEANUP_INTERVAL

if TYPE_CHECKING:
from ._core import Zeroconf

_TC_DELAY_RANDOM_INTERVAL = (400, 500)

_CLOSE_TIMEOUT = 3000 # ms


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

from ._listener import AsyncListener
from ._transport import _WrappedTransport, make_wrapped_transport

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(),
)
_CLOSE_TIMEOUT = 3000 # ms


class AsyncEngine:
Expand Down Expand Up @@ -154,9 +106,9 @@ async def _async_create_endpoints(self) -> None:
lambda: AsyncListener(self.zc), sock=s # type: ignore[arg-type, return-value]
)
self.protocols.append(cast(AsyncListener, protocol))
self.readers.append(_make_wrapped_transport(cast(asyncio.DatagramTransport, transport)))
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)))
self.senders.append(make_wrapped_transport(cast(asyncio.DatagramTransport, transport)))

def _async_cache_cleanup(self) -> None:
"""Periodic cache cleanup."""
Expand Down Expand Up @@ -198,182 +150,3 @@ def close(self) -> None:
if not self.loop.is_running():
return
run_coro_with_timeout(self._async_close(), self.loop, _CLOSE_TIMEOUT)


class AsyncListener:

"""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',
'last_message',
'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: # pragma: no branch
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"
QuietLogger.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."""
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