def create_response(
request: bytes,
services: Dict[str, FakeDnsService],
ip_filter: Optional[str] = None,
sleep_proxy: bool = False,
):
msg = dns.DnsMessage().unpack(request)
resp = dns.DnsMessage()
resp.flags = 0x0840
resp.questions = msg.questions
for question in resp.questions:
service, full_name = _lookup_service(question, services)
if service is None or (ip_filter
and ip_filter not in service.addresses):
continue
# For typing purposes, because service is not None, then full_name is not None
# either.
full_name = cast(str, full_name)
# Add answer
if full_name:
resp.answers.append(dns_utils.answer(question.qname, full_name))
# If acting as sleep proxy, just return a PTR
if sleep_proxy and question.qname.startswith("_"):
continue
# Add service (SRV) resource
if service.port:
local_name = dns.qname_encode(service.name + ".local")
rd = struct.pack(">3H", 0, 0, service.port) + local_name
resp.resources.append(
dns_utils.resource(full_name, dns.QueryType.SRV, rd))
# Add IP address(es)
for address in service.addresses:
ipaddr = IPv4Address(address).packed
resp.resources.append(
dns_utils.resource(service.name + ".local", dns.QueryType.A,
ipaddr))
# Add properties
if service.properties:
rd = dns_utils.properties(service.properties)
resp.resources.append(
dns_utils.resource(full_name, dns.QueryType.TXT, rd))
# Add model if present
if service.model:
rd = dns_utils.properties({"model": service.model.encode("utf-8")})
resp.resources.append(
dns_utils.resource(service.name + "._device-info._tcp.local",
dns.QueryType.TXT, rd))
return resp
def test_authority():
msg = dns.DnsMessage()
msg.authorities.append(
dns_utils.resource("test.local", dns.QueryType.A, b"\x01\x02\x03\x04"))
unpacked = dns.DnsMessage().unpack(msg.pack())
assert len(unpacked.authorities) == 1
record = unpacked.authorities[0]
assert record.qname == "test.local"
assert record.qtype == dns.QueryType.A
assert record.qclass == dns_utils.DEFAULT_QCLASS
assert record.ttl == dns_utils.DEFAULT_TTL
assert record.rd == "1.2.3.4"