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Add unicast property to DNSQuestion to determine if the QU bit is set #593

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Merged
bdraco merged 1 commit into from
Jun 13, 2021
Merged

Add unicast property to DNSQuestion to determine if the QU bit is set #593

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22 changes: 21 additions & 1 deletion tests/test_dns.py
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Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,7 @@
from typing import Dict, cast # noqa # used in type hints

import zeroconf as r
from zeroconf import const, current_time_millis
from zeroconf import DNSIncoming, const, current_time_millis
from zeroconf import (
DNSHinfo,
DNSText,
Expand Down Expand Up @@ -747,3 +747,23 @@ def test_tc_bit_not_set_in_answer_packet():
third_packet = r.DNSIncoming(packets[2])
assert third_packet.flags & const._FLAGS_TC == 0
assert third_packet.valid is True


# 4003 15.973052 192.168.107.68 224.0.0.251 MDNS 76 Standard query 0xffc4 PTR _raop._tcp.local, "QM" question
def test_qm_packet_parser():
"""Test we can parse a query packet with the QM bit."""
qm_packet = (
b'\xff\xc4\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x05_raop\x04_tcp\x05local\x00\x00\x0c\x00\x01'
)
parsed = DNSIncoming(qm_packet)
assert parsed.questions[0].unicast is False
assert ",QM," in str(parsed.questions[0])


# 389951 1450.577370 192.168.107.111 224.0.0.251 MDNS 115 Standard query 0x0000 PTR _companion-link._tcp.local, "QU" question OPT
def test_qu_packet_parser():
"""Test we can parse a query packet with the QU bit."""
qu_packet = b'\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x01\x0f_companion-link\x04_tcp\x05local\x00\x00\x0c\x80\x01\x00\x00)\x05\xa0\x00\x00\x11\x94\x00\x12\x00\x04\x00\x0e\x00dz{\x8a6\x9czF\x84,\xcaQ\xff'
parsed = DNSIncoming(qu_packet)
assert parsed.questions[0].unicast is True
assert ",QU," in str(parsed.questions[0])
35 changes: 23 additions & 12 deletions zeroconf/_dns.py
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Original file line number Diff line number Diff line change
Expand Up @@ -91,17 +91,14 @@ def get_type(t: int) -> str:

def entry_to_string(self, hdr: str, other: Optional[Union[bytes, str]]) -> str:
"""String representation with additional information"""
result = "%s[%s,%s" % (hdr, self.get_type(self.type), self.get_class_(self.class_))
if self.unique:
result += "-unique,"
else:
result += ","
result += self.name
if other is not None:
result += "]=%s" % cast(Any, other)
else:
result += "]"
return result
return "%s[%s,%s%s,%s]%s" % (
hdr,
self.get_type(self.type),
self.get_class_(self.class_),
"-unique" if self.unique else "",
self.name,
"=%s" % cast(Any, other) if other is not None else "",
)


class DNSQuestion(DNSEntry):
Expand All @@ -119,9 +116,23 @@ def answered_by(self, rec: 'DNSRecord') -> bool:
and self.name == rec.name
)

@property
def unicast(self) -> bool:
"""Returns true if the QU (not QM) is set.

unique shares the same mask as the one
used for unicast.
"""
return self.unique

def __repr__(self) -> str:
"""String representation"""
return DNSEntry.entry_to_string(self, "question", None)
return "%s[question,%s,%s,%s]" % (
self.get_type(self.type),
"QU" if self.unicast else "QM",
self.get_class_(self.class_),
self.name,
)


class DNSRecord(DNSEntry):
Expand Down