def test_tc_bit_not_set_in_answer_packet():
"""Verify the TC bit is not set when there are no questions and answers exceed the packet size."""
out = r.DNSOutgoing(const._FLAGS_QR_RESPONSE | const._FLAGS_AA)
for i in range(30):
out.add_answer_at_time(
DNSText(
("HASS Bridge W9DN %s._hap._tcp.local." % i),
const._TYPE_TXT,
const._CLASS_IN | const._CLASS_UNIQUE,
const._DNS_OTHER_TTL,
b'\x13md=HASS Bridge W9DN\x06pv=1.0\x14id=11:8E:DB:5B:5C:C5\x05c#=12\x04s#=1'
b'\x04ff=0\x04ci=2\x04sf=0\x0bsh=6fLM5A==',
),
0,
)
packets = out.packets()
assert len(packets) == 3
first_packet = r.DNSIncoming(packets[0])
assert first_packet.flags & const._FLAGS_TC == 0
assert first_packet.valid is True
second_packet = r.DNSIncoming(packets[1])
assert second_packet.flags & const._FLAGS_TC == 0
assert second_packet.valid is True
third_packet = r.DNSIncoming(packets[2])
assert third_packet.flags & const._FLAGS_TC == 0
assert third_packet.valid is True
def test_incoming_exception_handling(self):
generated = r.DNSOutgoing(0)
packet = generated.packet()
packet = packet[:8] + b"deadbeef" + packet[8:]
parsed = r.DNSIncoming(packet)
parsed = r.DNSIncoming(packet)
assert parsed.valid is False
def test_tc_bit_in_query_packet():
"""Verify the TC bit is set when known answers exceed the packet size."""
out = r.DNSOutgoing(const._FLAGS_QR_QUERY | const._FLAGS_AA)
type_ = "_hap._tcp.local."
out.add_question(r.DNSQuestion(type_, const._TYPE_PTR, const._CLASS_IN))
for i in range(30):
out.add_answer_at_time(
DNSText(
("HASS Bridge W9DN %s._hap._tcp.local." % i),
const._TYPE_TXT,
const._CLASS_IN | const._CLASS_UNIQUE,
const._DNS_OTHER_TTL,
b'\x13md=HASS Bridge W9DN\x06pv=1.0\x14id=11:8E:DB:5B:5C:C5\x05c#=12\x04s#=1'
b'\x04ff=0\x04ci=2\x04sf=0\x0bsh=6fLM5A==',
),
0,
)
packets = out.packets()
assert len(packets) == 3
first_packet = r.DNSIncoming(packets[0])
assert first_packet.truncated
assert first_packet.valid is True
second_packet = r.DNSIncoming(packets[1])
assert second_packet.truncated
assert second_packet.valid is True
third_packet = r.DNSIncoming(packets[2])
assert not third_packet.truncated
assert third_packet.valid is True
def test_ptr_optimization():
# instantiate a zeroconf instance
zc = Zeroconf(interfaces=['127.0.0.1'])
# service definition
type_ = "_test-srvc-type._tcp.local."
name = "xxxyyy"
registration_name = "%s.%s" % (name, type_)
desc = {'path': '/~paulsm/'}
info = ServiceInfo(
type_, registration_name, 80, 0, 0, desc, "ash-2.local.", addresses=[socket.inet_aton("10.0.1.2")]
)
# register
zc.register_service(info)
# Verify we won't respond for 1s with the same multicast
query = r.DNSOutgoing(const._FLAGS_QR_QUERY)
query.add_question(r.DNSQuestion(info.type, const._TYPE_PTR, const._CLASS_IN))
unicast_out, multicast_out = zc.query_handler.response(
[r.DNSIncoming(packet) for packet in query.packets()], None, const._MDNS_PORT
)
assert unicast_out is None
assert multicast_out is None
# Clear the cache to allow responding again
_clear_cache(zc)
# Verify we will now respond
query = r.DNSOutgoing(const._FLAGS_QR_QUERY)
query.add_question(r.DNSQuestion(info.type, const._TYPE_PTR, const._CLASS_IN))
unicast_out, multicast_out = zc.query_handler.response(
[r.DNSIncoming(packet) for packet in query.packets()], None, const._MDNS_PORT
)
assert multicast_out.id == query.id
assert unicast_out is None
assert multicast_out is not None
has_srv = has_txt = has_a = False
nbr_additionals = 0
nbr_answers = len(multicast_out.answers)
nbr_authorities = len(multicast_out.authorities)
for answer in multicast_out.additionals:
nbr_additionals += 1
if answer.type == const._TYPE_SRV:
has_srv = True
elif answer.type == const._TYPE_TXT:
has_txt = True
elif answer.type == const._TYPE_A:
has_a = True
assert nbr_answers == 1 and nbr_additionals == 3 and nbr_authorities == 0
assert has_srv and has_txt and has_a
# unregister
zc.unregister_service(info)
zc.close()
def mock_incoming_msg(
service_state_change: r.ServiceStateChange) -> r.DNSIncoming:
ttl = 120
generated = r.DNSOutgoing(const._FLAGS_QR_RESPONSE)
if service_state_change == r.ServiceStateChange.Updated:
generated.add_answer_at_time(
r.DNSText(
service_name,
const._TYPE_TXT,
const._CLASS_IN | const._CLASS_UNIQUE,
ttl,
service_text,
),
0,
)
return r.DNSIncoming(generated.packets()[0])
if service_state_change == r.ServiceStateChange.Removed:
ttl = 0
generated.add_answer_at_time(
r.DNSPointer(service_type, const._TYPE_PTR, const._CLASS_IN,
ttl, service_name), 0)
generated.add_answer_at_time(
r.DNSService(
service_name,
const._TYPE_SRV,
const._CLASS_IN | const._CLASS_UNIQUE,
ttl,
0,
0,
80,
service_server,
),
0,
)
generated.add_answer_at_time(
r.DNSText(service_name, const._TYPE_TXT,
const._CLASS_IN | const._CLASS_UNIQUE, ttl,
service_text),
0,
)
generated.add_answer_at_time(
r.DNSAddress(
service_server,
const._TYPE_A,
const._CLASS_IN | const._CLASS_UNIQUE,
ttl,
socket.inet_aton(service_address),
),
0,
)
return r.DNSIncoming(generated.packets()[0])
def test_only_one_answer_can_by_large(self):
"""Test that only the first answer in each packet can be large.
https://datatracker.ietf.org/doc/html/rfc6762#section-17
"""
generated = r.DNSOutgoing(const._FLAGS_QR_RESPONSE)
query = r.DNSIncoming(
r.DNSOutgoing(const._FLAGS_QR_QUERY).packets()[0])
for i in range(3):
generated.add_answer(
query,
r.DNSText(
"zoom._hap._tcp.local.",
const._TYPE_TXT,
const._CLASS_IN | const._CLASS_UNIQUE,
1200,
b'\x04ff=0\x04ci=2\x04sf=0\x0bsh=6fLM5A==' * 100,
),
)
generated.add_answer(
query,
r.DNSService(
"testname1.local.",
const._TYPE_SRV,
const._CLASS_IN | const._CLASS_UNIQUE,
const._DNS_HOST_TTL,
0,
0,
80,
"foo.local.",
),
)
assert len(generated.answers) == 4
packets = generated.packets()
assert len(packets) == 4
assert len(packets[0]) <= const._MAX_MSG_ABSOLUTE
assert len(packets[0]) > const._MAX_MSG_TYPICAL
assert len(packets[1]) <= const._MAX_MSG_ABSOLUTE
assert len(packets[1]) > const._MAX_MSG_TYPICAL
assert len(packets[2]) <= const._MAX_MSG_ABSOLUTE
assert len(packets[2]) > const._MAX_MSG_TYPICAL
assert len(packets[3]) <= const._MAX_MSG_TYPICAL
for packet in packets:
parsed = r.DNSIncoming(packet)
assert len(parsed.answers) == 1
def test_parse_own_packet_response(self):
generated = r.DNSOutgoing(r._FLAGS_QR_RESPONSE)
generated.add_answer_at_time(r.DNSService(
"æøå.local.", r._TYPE_SRV, r._CLASS_IN, r._DNS_TTL, 0, 0, 80, "foo.local."), 0)
parsed = r.DNSIncoming(generated.packet())
self.assertEqual(len(generated.answers), 1)
self.assertEqual(len(generated.answers), len(parsed.answers))
def testLongName(self):
generated = r.DNSOutgoing(r._FLAGS_QR_RESPONSE)
question = r.DNSQuestion(
"this.is.a.very.long.name.with.lots.of.parts.in.it.local.",
r._TYPE_SRV, r._CLASS_IN)
generated.addQuestion(question)
parsed = r.DNSIncoming(generated.packet())
def test_any_query_for_ptr():
"""Test that queries for ANY will return PTR records."""
zc = Zeroconf(interfaces=['127.0.0.1'])
type_ = "_anyptr._tcp.local."
name = "knownname"
registration_name = "%s.%s" % (name, type_)
desc = {'path': '/~paulsm/'}
server_name = "ash-2.local."
ipv6_address = socket.inet_pton(socket.AF_INET6, "2001:db8::1")
info = ServiceInfo(type_, registration_name, 80, 0, 0, desc, server_name, addresses=[ipv6_address])
zc.registry.add(info)
_clear_cache(zc)
generated = r.DNSOutgoing(const._FLAGS_QR_QUERY)
question = r.DNSQuestion(type_, const._TYPE_ANY, const._CLASS_IN)
generated.add_question(question)
packets = generated.packets()
_, multicast_out = zc.query_handler.response(
[r.DNSIncoming(packet) for packet in packets], "1.2.3.4", const._MDNS_PORT
)
assert multicast_out.answers[0][0].name == type_
assert multicast_out.answers[0][0].alias == registration_name
# unregister
zc.registry.remove(info)
zc.close()
def test_same_name(self):
name = "paired.local."
generated = r.DNSOutgoing(r._FLAGS_QR_RESPONSE)
question = r.DNSQuestion(name, r._TYPE_SRV, r._CLASS_IN)
generated.add_question(question)
generated.add_question(question)
r.DNSIncoming(generated.packet())
def mock_split_incoming_msg(
service_state_change: r.ServiceStateChange) -> r.DNSIncoming:
"""Mock an incoming message for the case where the packet is split."""
ttl = 120
generated = r.DNSOutgoing(const._FLAGS_QR_RESPONSE)
generated.add_answer_at_time(
r.DNSAddress(
service_server,
const._TYPE_A,
const._CLASS_IN | const._CLASS_UNIQUE,
ttl,
socket.inet_aton(service_address),
),
0,
)
generated.add_answer_at_time(
r.DNSService(
service_name,
const._TYPE_SRV,
const._CLASS_IN | const._CLASS_UNIQUE,
ttl,
0,
0,
80,
service_server,
),
0,
)
return r.DNSIncoming(generated.packets()[0])
def test_long_name(self):
generated = r.DNSOutgoing(const._FLAGS_QR_RESPONSE)
question = r.DNSQuestion(
"this.is.a.very.long.name.with.lots.of.parts.in.it.local.",
const._TYPE_SRV, const._CLASS_IN)
generated.add_question(question)
r.DNSIncoming(generated.packets()[0])
def test_invalid_packets_ignored_and_does_not_cause_loop_exception():
"""Ensure an invalid packet cannot cause the loop to collapse."""
zc = Zeroconf(interfaces=['127.0.0.1'])
generated = r.DNSOutgoing(0)
packet = generated.packets()[0]
packet = packet[:8] + b'deadbeef' + packet[8:]
parsed = r.DNSIncoming(packet)
assert parsed.valid is False
mock_out = unittest.mock.Mock()
mock_out.packets = lambda: [packet]
zc.send(mock_out)
generated = r.DNSOutgoing(const._FLAGS_QR_RESPONSE)
entry = r.DNSText(
"didnotcrashincoming._crash._tcp.local.",
const._TYPE_TXT,
const._CLASS_IN | const._CLASS_UNIQUE,
500,
b'path=/~paulsm/',
)
assert isinstance(entry, r.DNSText)
assert isinstance(entry, r.DNSRecord)
assert isinstance(entry, r.DNSEntry)
generated.add_answer_at_time(entry, 0)
zc.send(generated)
time.sleep(0.2)
zc.close()
assert zc.cache.get(entry) is not None
def test_incoming_circular_reference(self):
assert not r.DNSIncoming(
bytes.fromhex(
'01005e0000fb542a1bf0577608004500006897934000ff11d81bc0a86a31e00000fb'
'14e914e90054f9b2000084000000000100000000095f7365727669636573075f646e'
'732d7364045f756470056c6f63616c00000c0001000011940018105f73706f746966'
'792d636f6e6e656374045f746370c023')).valid
def test_aaaa_query():
"""Test that queries for AAAA records work."""
zc = Zeroconf(interfaces=['127.0.0.1'])
type_ = "_knownservice._tcp.local."
name = "knownname"
registration_name = "%s.%s" % (name, type_)
desc = {'path': '/~paulsm/'}
server_name = "ash-2.local."
ipv6_address = socket.inet_pton(socket.AF_INET6, "2001:db8::1")
info = ServiceInfo(type_,
registration_name,
80,
0,
0,
desc,
server_name,
addresses=[ipv6_address])
zc.register_service(info)
_clear_cache(zc)
generated = r.DNSOutgoing(const._FLAGS_QR_QUERY)
question = r.DNSQuestion(server_name, const._TYPE_AAAA, const._CLASS_IN)
generated.add_question(question)
packets = generated.packets()
_, multicast_out = zc.query_handler.response(r.DNSIncoming(packets[0]),
"1.2.3.4", const._MDNS_PORT)
assert multicast_out.answers[0][0].address == ipv6_address
# unregister
zc.unregister_service(info)
zc.close()
def test_incoming_unknown_type(self):
generated = r.DNSOutgoing(0)
answer = r.DNSAddress("a", r._TYPE_SOA, r._CLASS_IN, 1, b"a")
generated.add_additional_answer(answer)
packet = generated.packet()
parsed = r.DNSIncoming(packet)
assert len(parsed.answers) == 0
assert parsed.is_query() != parsed.is_response()
def test_match_question(self):
generated = r.DNSOutgoing(r._FLAGS_QR_QUERY)
question = r.DNSQuestion("testname.local.", r._TYPE_SRV, r._CLASS_IN)
generated.add_question(question)
parsed = r.DNSIncoming(generated.packet())
self.assertEqual(len(generated.questions), 1)
self.assertEqual(len(generated.questions), len(parsed.questions))
self.assertEqual(question, parsed.questions[0])
def mock_incoming_msg(
service_state_change: r.ServiceStateChange, service_type: str, service_name: str, ttl: int
) -> r.DNSIncoming:
generated = r.DNSOutgoing(const._FLAGS_QR_RESPONSE)
generated.add_answer_at_time(
r.DNSPointer(service_type, const._TYPE_PTR, const._CLASS_IN, ttl, service_name), 0
)
return r.DNSIncoming(generated.packets()[0])
def mock_incoming_msg(records) -> r.DNSIncoming:
generated = r.DNSOutgoing(const._FLAGS_QR_RESPONSE)
for record in records:
generated.add_answer_at_time(record, 0)
return r.DNSIncoming(generated.packets()[0])
def test_match_question(self):
generated = r.DNSOutgoing(const._FLAGS_QR_QUERY)
question = r.DNSQuestion("testname.local.", const._TYPE_SRV,
const._CLASS_IN)
generated.add_question(question)
parsed = r.DNSIncoming(generated.packets()[0])
assert len(generated.questions) == 1
assert len(generated.questions) == len(parsed.questions)
assert question == parsed.questions[0]
def test_questions_do_not_end_up_every_packet(self):
"""Test that questions are not sent again when multiple packets are needed.
https://datatracker.ietf.org/doc/html/rfc6762#section-7.2
Sometimes a Multicast DNS querier will already have too many answers
to fit in the Known-Answer Section of its query packets.... It MUST
immediately follow the packet with another query packet containing no
questions and as many more Known-Answer records as will fit.
"""
generated = r.DNSOutgoing(const._FLAGS_QR_QUERY)
for i in range(35):
question = r.DNSQuestion(f"testname{i}.local.", const._TYPE_SRV,
const._CLASS_IN)
generated.add_question(question)
answer = r.DNSService(
f"testname{i}.local.",
const._TYPE_SRV,
const._CLASS_IN | const._CLASS_UNIQUE,
const._DNS_HOST_TTL,
0,
0,
80,
f"foo{i}.local.",
)
generated.add_answer_at_time(answer, 0)
assert len(generated.questions) == 35
assert len(generated.answers) == 35
packets = generated.packets()
assert len(packets) == 2
assert len(packets[0]) <= const._MAX_MSG_TYPICAL
assert len(packets[1]) <= const._MAX_MSG_TYPICAL
parsed1 = r.DNSIncoming(packets[0])
assert len(parsed1.questions) == 35
assert len(parsed1.answers) == 33
parsed2 = r.DNSIncoming(packets[1])
assert len(parsed2.questions) == 0
assert len(parsed2.answers) == 2
def test_many_questions(self):
"""Test many questions get seperated into multiple packets."""
generated = r.DNSOutgoing(const._FLAGS_QR_QUERY)
questions = []
for i in range(100):
question = r.DNSQuestion(f"testname{i}.local.", const._TYPE_SRV,
const._CLASS_IN)
generated.add_question(question)
questions.append(question)
assert len(generated.questions) == 100
packets = generated.packets()
assert len(packets) == 2
assert len(packets[0]) < const._MAX_MSG_TYPICAL
assert len(packets[1]) < const._MAX_MSG_TYPICAL
parsed1 = r.DNSIncoming(packets[0])
assert len(parsed1.questions) == 85
parsed2 = r.DNSIncoming(packets[1])
assert len(parsed2.questions) == 15
def test_incoming_ipv6(self):
addr = "2606:2800:220:1:248:1893:25c8:1946" # example.com
packed = socket.inet_pton(socket.AF_INET6, addr)
generated = r.DNSOutgoing(0)
answer = r.DNSAddress('domain', r._TYPE_AAAA, r._CLASS_IN, 1, packed)
generated.add_additional_answer(answer)
packet = generated.packet()
parsed = r.DNSIncoming(packet)
record = parsed.answers[0]
assert isinstance(record, r.DNSAddress)
assert record.address == packed
def test_dns_hinfo(self):
generated = r.DNSOutgoing(0)
generated.add_additional_answer(DNSHinfo('irrelevant', r._TYPE_HINFO, 0, 0, 'cpu', 'os'))
parsed = r.DNSIncoming(generated.packet())
answer = cast(r.DNSHinfo, parsed.answers[0])
self.assertEqual(answer.cpu, u'cpu')
self.assertEqual(answer.os, u'os')
generated = r.DNSOutgoing(0)
generated.add_additional_answer(DNSHinfo('irrelevant', r._TYPE_HINFO, 0, 0, 'cpu', 'x' * 257))
self.assertRaises(r.NamePartTooLongException, generated.packet)
def send(out, addr=const._MDNS_ADDR, port=const._MDNS_PORT):
"""Sends an outgoing packet."""
pout = r.DNSIncoming(out.packets()[0])
nonlocal nbr_answers
for answer in pout.answers:
nbr_answers += 1
if not answer.ttl > expected_ttl / 2:
unexpected_ttl.set()
got_query.set()
old_send(out, addr=addr, port=port)
def send(out, addr=r._MDNS_ADDR, port=r._MDNS_PORT):
"""Sends an outgoing packet."""
pout = r.DNSIncoming(out.packet())
for answer in pout.answers:
nbr_queries[0] += 1
if not answer.ttl > expected_ttl / 2:
unexpected_ttl.set()
got_query.set()
old_send(out, addr=addr, port=port)
def test_ptr_optimization():
# instantiate a zeroconf instance
zc = Zeroconf(interfaces=['127.0.0.1'])
# service definition
type_ = "_test-srvc-type._tcp.local."
name = "xxxyyy"
registration_name = "%s.%s" % (name, type_)
desc = {'path': '/~paulsm/'}
info = ServiceInfo(type_, registration_name, socket.inet_aton("10.0.1.2"),
80, 0, 0, desc, "ash-2.local.")
# we are going to monkey patch the zeroconf send to check packet sizes
old_send = zc.send
nbr_answers = nbr_additionals = nbr_authorities = 0
has_srv = has_txt = has_a = False
def send(out, addr=r._MDNS_ADDR, port=r._MDNS_PORT):
"""Sends an outgoing packet."""
nonlocal nbr_answers, nbr_additionals, nbr_authorities
nonlocal has_srv, has_txt, has_a
nbr_answers += len(out.answers)
nbr_authorities += len(out.authorities)
for answer in out.additionals:
nbr_additionals += 1
if answer.type == r._TYPE_SRV:
has_srv = True
elif answer.type == r._TYPE_TXT:
has_txt = True
elif answer.type == r._TYPE_A:
has_a = True
old_send(out, addr=addr, port=port)
# monkey patch the zeroconf send
setattr(zc, "send", send)
# register
zc.register_service(info)
nbr_answers = nbr_additionals = nbr_authorities = 0
# query
query = r.DNSOutgoing(r._FLAGS_QR_QUERY | r._FLAGS_AA)
query.add_question(r.DNSQuestion(info.type, r._TYPE_PTR, r._CLASS_IN))
zc.handle_query(r.DNSIncoming(query.packet()), r._MDNS_ADDR, r._MDNS_PORT)
assert nbr_answers == 1 and nbr_additionals == 3 and nbr_authorities == 0
assert has_srv and has_txt and has_a
# unregister
zc.unregister_service(info)
def test_dns_hinfo(self):
generated = r.DNSOutgoing(0)
generated.add_additional_answer(
DNSHinfo("irrelevant", r._TYPE_HINFO, 0, 0, "cpu", "os"))
parsed = r.DNSIncoming(generated.packet())
self.assertEqual(parsed.answers[0].cpu, u"cpu")
self.assertEqual(parsed.answers[0].os, u"os")
generated = r.DNSOutgoing(0)
generated.add_additional_answer(
DNSHinfo("irrelevant", r._TYPE_HINFO, 0, 0, "cpu", "x" * 257))
self.assertRaises(r.NamePartTooLongException, generated.packet)
def test_multi_packet_known_answer_supression():
zc = Zeroconf(interfaces=['127.0.0.1'])
type_ = "_handlermultis._tcp.local."
name = "knownname"
name2 = "knownname2"
name3 = "knownname3"
registration_name = "%s.%s" % (name, type_)
registration2_name = "%s.%s" % (name2, type_)
registration3_name = "%s.%s" % (name3, type_)
desc = {'path': '/~paulsm/'}
server_name = "ash-2.local."
server_name2 = "ash-3.local."
server_name3 = "ash-4.local."
info = ServiceInfo(
type_, registration_name, 80, 0, 0, desc, server_name, addresses=[socket.inet_aton("10.0.1.2")]
)
info2 = ServiceInfo(
type_, registration2_name, 80, 0, 0, desc, server_name2, addresses=[socket.inet_aton("10.0.1.2")]
)
info3 = ServiceInfo(
type_, registration3_name, 80, 0, 0, desc, server_name3, addresses=[socket.inet_aton("10.0.1.2")]
)
zc.registry.add(info)
zc.registry.add(info2)
zc.registry.add(info3)
now = current_time_millis()
_clear_cache(zc)
# Test PTR supression
generated = r.DNSOutgoing(const._FLAGS_QR_QUERY)
question = r.DNSQuestion(type_, const._TYPE_PTR, const._CLASS_IN)
generated.add_question(question)
for _ in range(1000):
# Add so many answers we end up with another packet
generated.add_answer_at_time(info.dns_pointer(), now)
generated.add_answer_at_time(info2.dns_pointer(), now)
generated.add_answer_at_time(info3.dns_pointer(), now)
packets = generated.packets()
assert len(packets) > 1
unicast_out, multicast_out = zc.query_handler.response(
[r.DNSIncoming(packet) for packet in packets], "1.2.3.4", const._MDNS_PORT
)
assert unicast_out is None
assert multicast_out is None
# unregister
zc.registry.remove(info)
zc.registry.remove(info2)
zc.registry.remove(info3)
zc.close()
def test_massive_probe_packet_split(self):
"""Test probe with many authorative answers."""
generated = r.DNSOutgoing(const._FLAGS_QR_QUERY | const._FLAGS_AA)
questions = []
for _ in range(30):
question = r.DNSQuestion(f"_hap._tcp.local.", const._TYPE_PTR,
const._CLASS_IN | const._CLASS_UNIQUE)
generated.add_question(question)
questions.append(question)
assert len(generated.questions) == 30
now = current_time_millis()
for _ in range(200):
authorative_answer = r.DNSPointer(
"myservice{i}_tcp._tcp.local.",
const._TYPE_PTR,
const._CLASS_IN | const._CLASS_UNIQUE,
const._DNS_OTHER_TTL,
'123.local.',
)
generated.add_authorative_answer(authorative_answer)
packets = generated.packets()
assert len(packets) == 3
assert len(packets[0]) <= const._MAX_MSG_TYPICAL
assert len(packets[1]) <= const._MAX_MSG_TYPICAL
assert len(packets[2]) <= const._MAX_MSG_TYPICAL
parsed1 = r.DNSIncoming(packets[0])
assert parsed1.questions[0].unicast is True
assert len(parsed1.questions) == 30
assert parsed1.num_authorities == 88
assert parsed1.flags & const._FLAGS_TC == const._FLAGS_TC
parsed2 = r.DNSIncoming(packets[1])
assert len(parsed2.questions) == 0
assert parsed2.num_authorities == 101
assert parsed2.flags & const._FLAGS_TC == const._FLAGS_TC
parsed3 = r.DNSIncoming(packets[2])
assert len(parsed3.questions) == 0
assert parsed3.num_authorities == 11
assert parsed3.flags & const._FLAGS_TC == 0
