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test_listener.py
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222 lines (177 loc) · 7.46 KB
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#!/usr/bin/env python
""" Unit tests for zeroconf._listener """
import logging
import unittest
import unittest.mock
from typing import Tuple, Union
from unittest.mock import MagicMock, patch
import zeroconf as r
from zeroconf import Zeroconf, _engine, _listener, const, current_time_millis
from zeroconf._protocol import outgoing
from zeroconf._protocol.incoming import DNSIncoming
from . import QuestionHistoryWithoutSuppression
log = logging.getLogger('zeroconf')
original_logging_level = logging.NOTSET
def setup_module():
global original_logging_level
original_logging_level = log.level
log.setLevel(logging.DEBUG)
def teardown_module():
if original_logging_level != logging.NOTSET:
log.setLevel(original_logging_level)
def test_guard_against_oversized_packets():
"""Ensure we do not process oversized packets.
These packets can quickly overwhelm the system.
"""
zc = Zeroconf(interfaces=['127.0.0.1'])
generated = r.DNSOutgoing(const._FLAGS_QR_RESPONSE)
for i in range(5000):
generated.add_answer_at_time(
r.DNSText(
"packet{i}.local.",
const._TYPE_TXT,
const._CLASS_IN | const._CLASS_UNIQUE,
500,
b'path=/~paulsm/',
),
0,
)
try:
# We are patching to generate an oversized packet
with patch.object(outgoing, "_MAX_MSG_ABSOLUTE", 100000), patch.object(
outgoing, "_MAX_MSG_TYPICAL", 100000
):
over_sized_packet = generated.packets()[0]
assert len(over_sized_packet) > const._MAX_MSG_ABSOLUTE
except AttributeError:
# cannot patch with cython
zc.close()
return
generated = r.DNSOutgoing(const._FLAGS_QR_RESPONSE)
okpacket_record = r.DNSText(
"okpacket.local.",
const._TYPE_TXT,
const._CLASS_IN | const._CLASS_UNIQUE,
500,
b'path=/~paulsm/',
)
generated.add_answer_at_time(
okpacket_record,
0,
)
ok_packet = generated.packets()[0]
# We cannot test though the network interface as some operating systems
# will guard against the oversized packet and we won't see it.
listener = _listener.AsyncListener(zc)
listener.transport = unittest.mock.MagicMock()
listener.datagram_received(ok_packet, ('127.0.0.1', const._MDNS_PORT))
assert zc.cache.async_get_unique(okpacket_record) is not None
listener.datagram_received(over_sized_packet, ('127.0.0.1', const._MDNS_PORT))
assert (
zc.cache.async_get_unique(
r.DNSText(
"packet0.local.",
const._TYPE_TXT,
const._CLASS_IN | const._CLASS_UNIQUE,
500,
b'path=/~paulsm/',
)
)
is None
)
logging.getLogger('zeroconf').setLevel(logging.INFO)
listener.datagram_received(over_sized_packet, ('::1', const._MDNS_PORT, 1, 1))
assert (
zc.cache.async_get_unique(
r.DNSText(
"packet0.local.",
const._TYPE_TXT,
const._CLASS_IN | const._CLASS_UNIQUE,
500,
b'path=/~paulsm/',
)
)
is None
)
zc.close()
def test_guard_against_duplicate_packets():
"""Ensure we do not process duplicate packets.
These packets can quickly overwhelm the system.
"""
zc = Zeroconf(interfaces=['127.0.0.1'])
zc.question_history = QuestionHistoryWithoutSuppression()
class SubListener(_listener.AsyncListener):
def handle_query_or_defer(
self,
msg: DNSIncoming,
addr: str,
port: int,
transport: _engine._WrappedTransport,
v6_flow_scope: Union[Tuple[()], Tuple[int, int]] = (),
) -> None:
"""Handle a query or defer it for later processing."""
super().handle_query_or_defer(msg, addr, port, transport, v6_flow_scope)
listener = SubListener(zc)
listener.transport = MagicMock()
query = r.DNSOutgoing(const._FLAGS_QR_QUERY, multicast=True)
question = r.DNSQuestion("x._http._tcp.local.", const._TYPE_PTR, const._CLASS_IN)
query.add_question(question)
packet_with_qm_question = query.packets()[0]
query3 = r.DNSOutgoing(const._FLAGS_QR_QUERY, multicast=True)
question3 = r.DNSQuestion("x._ay._tcp.local.", const._TYPE_PTR, const._CLASS_IN)
query3.add_question(question3)
packet_with_qm_question2 = query3.packets()[0]
query2 = r.DNSOutgoing(const._FLAGS_QR_QUERY, multicast=True)
question2 = r.DNSQuestion("x._http._tcp.local.", const._TYPE_PTR, const._CLASS_IN)
question2.unicast = True
query2.add_question(question2)
packet_with_qu_question = query2.packets()[0]
addrs = ("1.2.3.4", 43)
with patch.object(_listener, "current_time_millis") as _current_time_millis, patch.object(
listener, "handle_query_or_defer"
) as _handle_query_or_defer:
start_time = current_time_millis()
_current_time_millis.return_value = start_time
listener.datagram_received(packet_with_qm_question, addrs)
_handle_query_or_defer.assert_called_once()
_handle_query_or_defer.reset_mock()
# Now call with the same packet again and handle_query_or_defer should not fire
listener.datagram_received(packet_with_qm_question, addrs)
_handle_query_or_defer.assert_not_called()
_handle_query_or_defer.reset_mock()
# Now walk time forward 1000 seconds
_current_time_millis.return_value = start_time + 1000
# Now call with the same packet again and handle_query_or_defer should fire
listener.datagram_received(packet_with_qm_question, addrs)
_handle_query_or_defer.assert_called_once()
_handle_query_or_defer.reset_mock()
# Now call with the different packet and handle_query_or_defer should fire
listener.datagram_received(packet_with_qm_question2, addrs)
_handle_query_or_defer.assert_called_once()
_handle_query_or_defer.reset_mock()
# Now call with the different packet and handle_query_or_defer should fire
listener.datagram_received(packet_with_qm_question, addrs)
_handle_query_or_defer.assert_called_once()
_handle_query_or_defer.reset_mock()
# Now call with the different packet with qu question and handle_query_or_defer should fire
listener.datagram_received(packet_with_qu_question, addrs)
_handle_query_or_defer.assert_called_once()
_handle_query_or_defer.reset_mock()
# Now call again with the same packet that has a qu question and handle_query_or_defer should fire
listener.datagram_received(packet_with_qu_question, addrs)
_handle_query_or_defer.assert_called_once()
_handle_query_or_defer.reset_mock()
log.setLevel(logging.WARNING)
# Call with the QM packet again
listener.datagram_received(packet_with_qm_question, addrs)
_handle_query_or_defer.assert_called_once()
_handle_query_or_defer.reset_mock()
# Now call with the same packet again and handle_query_or_defer should not fire
listener.datagram_received(packet_with_qm_question, addrs)
_handle_query_or_defer.assert_not_called()
_handle_query_or_defer.reset_mock()
# Now call with garbage
listener.datagram_received(b'garbage', addrs)
_handle_query_or_defer.assert_not_called()
_handle_query_or_defer.reset_mock()
zc.close()