/usr/share/pyshared/twisted/names/test/test_rootresolve.py is in python-twisted-names 11.1.0-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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# See LICENSE for details.
"""
Test cases for Twisted.names' root resolver.
"""
from random import randrange
from zope.interface import implements
from zope.interface.verify import verifyClass
from twisted.python.log import msg
from twisted.trial import util
from twisted.trial.unittest import TestCase
from twisted.internet.defer import Deferred, succeed, gatherResults
from twisted.internet.task import Clock
from twisted.internet.address import IPv4Address
from twisted.internet.interfaces import IReactorUDP, IUDPTransport
from twisted.names.root import Resolver, lookupNameservers, lookupAddress
from twisted.names.root import extractAuthority, discoverAuthority, retry
from twisted.names.dns import IN, HS, A, NS, CNAME, OK, ENAME, Record_CNAME
from twisted.names.dns import Query, Message, RRHeader, Record_A, Record_NS
from twisted.names.error import DNSNameError, ResolverError
class MemoryDatagramTransport(object):
"""
This L{IUDPTransport} implementation enforces the usual connection rules
and captures sent traffic in a list for later inspection.
@ivar _host: The host address to which this transport is bound.
@ivar _protocol: The protocol connected to this transport.
@ivar _sentPackets: A C{list} of two-tuples of the datagrams passed to
C{write} and the addresses to which they are destined.
@ivar _connectedTo: C{None} if this transport is unconnected, otherwise an
address to which all traffic is supposedly sent.
@ivar _maxPacketSize: An C{int} giving the maximum length of a datagram
which will be successfully handled by C{write}.
"""
implements(IUDPTransport)
def __init__(self, host, protocol, maxPacketSize):
self._host = host
self._protocol = protocol
self._sentPackets = []
self._connectedTo = None
self._maxPacketSize = maxPacketSize
def getHost(self):
"""
Return the address which this transport is pretending to be bound
to.
"""
return IPv4Address('UDP', *self._host)
def connect(self, host, port):
"""
Connect this transport to the given address.
"""
if self._connectedTo is not None:
raise ValueError("Already connected")
self._connectedTo = (host, port)
def write(self, datagram, addr=None):
"""
Send the given datagram.
"""
if addr is None:
addr = self._connectedTo
if addr is None:
raise ValueError("Need an address")
if len(datagram) > self._maxPacketSize:
raise ValueError("Packet too big")
self._sentPackets.append((datagram, addr))
def stopListening(self):
"""
Shut down this transport.
"""
self._protocol.stopProtocol()
return succeed(None)
verifyClass(IUDPTransport, MemoryDatagramTransport)
class MemoryReactor(Clock):
"""
An L{IReactorTime} and L{IReactorUDP} provider.
Time is controlled deterministically via the base class, L{Clock}. UDP is
handled in-memory by connecting protocols to instances of
L{MemoryDatagramTransport}.
@ivar udpPorts: A C{dict} mapping port numbers to instances of
L{MemoryDatagramTransport}.
"""
implements(IReactorUDP)
def __init__(self):
Clock.__init__(self)
self.udpPorts = {}
def listenUDP(self, port, protocol, interface='', maxPacketSize=8192):
"""
Pretend to bind a UDP port and connect the given protocol to it.
"""
if port == 0:
while True:
port = randrange(1, 2 ** 16)
if port not in self.udpPorts:
break
if port in self.udpPorts:
raise ValueError("Address in use")
transport = MemoryDatagramTransport(
(interface, port), protocol, maxPacketSize)
self.udpPorts[port] = transport
protocol.makeConnection(transport)
return transport
verifyClass(IReactorUDP, MemoryReactor)
class RootResolverTests(TestCase):
"""
Tests for L{twisted.names.root.Resolver}.
"""
def _queryTest(self, filter):
"""
Invoke L{Resolver._query} and verify that it sends the correct DNS
query. Deliver a canned response to the query and return whatever the
L{Deferred} returned by L{Resolver._query} fires with.
@param filter: The value to pass for the C{filter} parameter to
L{Resolver._query}.
"""
reactor = MemoryReactor()
resolver = Resolver([], reactor=reactor)
d = resolver._query(
Query('foo.example.com', A, IN), [('1.1.2.3', 1053)], (30,),
filter)
# A UDP port should have been started.
portNumber, transport = reactor.udpPorts.popitem()
# And a DNS packet sent.
[(packet, address)] = transport._sentPackets
msg = Message()
msg.fromStr(packet)
# It should be a query with the parameters used above.
self.assertEqual(msg.queries, [Query('foo.example.com', A, IN)])
self.assertEqual(msg.answers, [])
self.assertEqual(msg.authority, [])
self.assertEqual(msg.additional, [])
response = []
d.addCallback(response.append)
self.assertEqual(response, [])
# Once a reply is received, the Deferred should fire.
del msg.queries[:]
msg.answer = 1
msg.answers.append(RRHeader('foo.example.com', payload=Record_A('5.8.13.21')))
transport._protocol.datagramReceived(msg.toStr(), ('1.1.2.3', 1053))
return response[0]
def test_filteredQuery(self):
"""
L{Resolver._query} accepts a L{Query} instance and an address, issues
the query, and returns a L{Deferred} which fires with the response to
the query. If a true value is passed for the C{filter} parameter, the
result is a three-tuple of lists of records.
"""
answer, authority, additional = self._queryTest(True)
self.assertEqual(
answer,
[RRHeader('foo.example.com', payload=Record_A('5.8.13.21', ttl=0))])
self.assertEqual(authority, [])
self.assertEqual(additional, [])
def test_unfilteredQuery(self):
"""
Similar to L{test_filteredQuery}, but for the case where a false value
is passed for the C{filter} parameter. In this case, the result is a
L{Message} instance.
"""
message = self._queryTest(False)
self.assertIsInstance(message, Message)
self.assertEqual(message.queries, [])
self.assertEqual(
message.answers,
[RRHeader('foo.example.com', payload=Record_A('5.8.13.21', ttl=0))])
self.assertEqual(message.authority, [])
self.assertEqual(message.additional, [])
def _respond(self, answers=[], authority=[], additional=[], rCode=OK):
"""
Create a L{Message} suitable for use as a response to a query.
@param answers: A C{list} of two-tuples giving data for the answers
section of the message. The first element of each tuple is a name
for the L{RRHeader}. The second element is the payload.
@param authority: A C{list} like C{answers}, but for the authority
section of the response.
@param additional: A C{list} like C{answers}, but for the
additional section of the response.
@param rCode: The response code the message will be created with.
@return: A new L{Message} initialized with the given values.
"""
response = Message(rCode=rCode)
for (section, data) in [(response.answers, answers),
(response.authority, authority),
(response.additional, additional)]:
section.extend([
RRHeader(name, record.TYPE, getattr(record, 'CLASS', IN),
payload=record)
for (name, record) in data])
return response
def _getResolver(self, serverResponses, maximumQueries=10):
"""
Create and return a new L{root.Resolver} modified to resolve queries
against the record data represented by C{servers}.
@param serverResponses: A mapping from dns server addresses to
mappings. The inner mappings are from query two-tuples (name,
type) to dictionaries suitable for use as **arguments to
L{_respond}. See that method for details.
"""
roots = ['1.1.2.3']
resolver = Resolver(roots, maximumQueries)
def query(query, serverAddresses, timeout, filter):
msg("Query for QNAME %s at %r" % (query.name, serverAddresses))
for addr in serverAddresses:
try:
server = serverResponses[addr]
except KeyError:
continue
records = server[str(query.name), query.type]
return succeed(self._respond(**records))
resolver._query = query
return resolver
def test_lookupAddress(self):
"""
L{root.Resolver.lookupAddress} looks up the I{A} records for the
specified hostname by first querying one of the root servers the
resolver was created with and then following the authority delegations
until a result is received.
"""
servers = {
('1.1.2.3', 53): {
('foo.example.com', A): {
'authority': [('foo.example.com', Record_NS('ns1.example.com'))],
'additional': [('ns1.example.com', Record_A('34.55.89.144'))],
},
},
('34.55.89.144', 53): {
('foo.example.com', A): {
'answers': [('foo.example.com', Record_A('10.0.0.1'))],
}
},
}
resolver = self._getResolver(servers)
d = resolver.lookupAddress('foo.example.com')
d.addCallback(lambda (ans, auth, add): ans[0].payload.dottedQuad())
d.addCallback(self.assertEqual, '10.0.0.1')
return d
def test_lookupChecksClass(self):
"""
If a response includes a record with a class different from the one
in the query, it is ignored and lookup continues until a record with
the right class is found.
"""
badClass = Record_A('10.0.0.1')
badClass.CLASS = HS
servers = {
('1.1.2.3', 53): {
('foo.example.com', A): {
'answers': [('foo.example.com', badClass)],
'authority': [('foo.example.com', Record_NS('ns1.example.com'))],
'additional': [('ns1.example.com', Record_A('10.0.0.2'))],
},
},
('10.0.0.2', 53): {
('foo.example.com', A): {
'answers': [('foo.example.com', Record_A('10.0.0.3'))],
},
},
}
resolver = self._getResolver(servers)
d = resolver.lookupAddress('foo.example.com')
d.addCallback(lambda (ans, auth, add): ans[0].payload)
d.addCallback(self.assertEqual, Record_A('10.0.0.3'))
return d
def test_missingGlue(self):
"""
If an intermediate response includes no glue records for the
authorities, separate queries are made to find those addresses.
"""
servers = {
('1.1.2.3', 53): {
('foo.example.com', A): {
'authority': [('foo.example.com', Record_NS('ns1.example.org'))],
# Conspicuous lack of an additional section naming ns1.example.com
},
('ns1.example.org', A): {
'answers': [('ns1.example.org', Record_A('10.0.0.1'))],
},
},
('10.0.0.1', 53): {
('foo.example.com', A): {
'answers': [('foo.example.com', Record_A('10.0.0.2'))],
},
},
}
resolver = self._getResolver(servers)
d = resolver.lookupAddress('foo.example.com')
d.addCallback(lambda (ans, auth, add): ans[0].payload.dottedQuad())
d.addCallback(self.assertEqual, '10.0.0.2')
return d
def test_missingName(self):
"""
If a name is missing, L{Resolver.lookupAddress} returns a L{Deferred}
which fails with L{DNSNameError}.
"""
servers = {
('1.1.2.3', 53): {
('foo.example.com', A): {
'rCode': ENAME,
},
},
}
resolver = self._getResolver(servers)
d = resolver.lookupAddress('foo.example.com')
return self.assertFailure(d, DNSNameError)
def test_answerless(self):
"""
If a query is responded to with no answers or nameserver records, the
L{Deferred} returned by L{Resolver.lookupAddress} fires with
L{ResolverError}.
"""
servers = {
('1.1.2.3', 53): {
('example.com', A): {
},
},
}
resolver = self._getResolver(servers)
d = resolver.lookupAddress('example.com')
return self.assertFailure(d, ResolverError)
def test_delegationLookupError(self):
"""
If there is an error resolving the nameserver in a delegation response,
the L{Deferred} returned by L{Resolver.lookupAddress} fires with that
error.
"""
servers = {
('1.1.2.3', 53): {
('example.com', A): {
'authority': [('example.com', Record_NS('ns1.example.com'))],
},
('ns1.example.com', A): {
'rCode': ENAME,
},
},
}
resolver = self._getResolver(servers)
d = resolver.lookupAddress('example.com')
return self.assertFailure(d, DNSNameError)
def test_delegationLookupEmpty(self):
"""
If there are no records in the response to a lookup of a delegation
nameserver, the L{Deferred} returned by L{Resolver.lookupAddress} fires
with L{ResolverError}.
"""
servers = {
('1.1.2.3', 53): {
('example.com', A): {
'authority': [('example.com', Record_NS('ns1.example.com'))],
},
('ns1.example.com', A): {
},
},
}
resolver = self._getResolver(servers)
d = resolver.lookupAddress('example.com')
return self.assertFailure(d, ResolverError)
def test_lookupNameservers(self):
"""
L{Resolver.lookupNameservers} is like L{Resolver.lookupAddress}, except
it queries for I{NS} records instead of I{A} records.
"""
servers = {
('1.1.2.3', 53): {
('example.com', A): {
'rCode': ENAME,
},
('example.com', NS): {
'answers': [('example.com', Record_NS('ns1.example.com'))],
},
},
}
resolver = self._getResolver(servers)
d = resolver.lookupNameservers('example.com')
d.addCallback(lambda (ans, auth, add): str(ans[0].payload.name))
d.addCallback(self.assertEqual, 'ns1.example.com')
return d
def test_returnCanonicalName(self):
"""
If a I{CNAME} record is encountered as the answer to a query for
another record type, that record is returned as the answer.
"""
servers = {
('1.1.2.3', 53): {
('example.com', A): {
'answers': [('example.com', Record_CNAME('example.net')),
('example.net', Record_A('10.0.0.7'))],
},
},
}
resolver = self._getResolver(servers)
d = resolver.lookupAddress('example.com')
d.addCallback(lambda (ans, auth, add): ans)
d.addCallback(
self.assertEqual,
[RRHeader('example.com', CNAME, payload=Record_CNAME('example.net')),
RRHeader('example.net', A, payload=Record_A('10.0.0.7'))])
return d
def test_followCanonicalName(self):
"""
If no record of the requested type is included in a response, but a
I{CNAME} record for the query name is included, queries are made to
resolve the value of the I{CNAME}.
"""
servers = {
('1.1.2.3', 53): {
('example.com', A): {
'answers': [('example.com', Record_CNAME('example.net'))],
},
('example.net', A): {
'answers': [('example.net', Record_A('10.0.0.5'))],
},
},
}
resolver = self._getResolver(servers)
d = resolver.lookupAddress('example.com')
d.addCallback(lambda (ans, auth, add): ans)
d.addCallback(
self.assertEqual,
[RRHeader('example.com', CNAME, payload=Record_CNAME('example.net')),
RRHeader('example.net', A, payload=Record_A('10.0.0.5'))])
return d
def test_detectCanonicalNameLoop(self):
"""
If there is a cycle between I{CNAME} records in a response, this is
detected and the L{Deferred} returned by the lookup method fails
with L{ResolverError}.
"""
servers = {
('1.1.2.3', 53): {
('example.com', A): {
'answers': [('example.com', Record_CNAME('example.net')),
('example.net', Record_CNAME('example.com'))],
},
},
}
resolver = self._getResolver(servers)
d = resolver.lookupAddress('example.com')
return self.assertFailure(d, ResolverError)
def test_boundedQueries(self):
"""
L{Resolver.lookupAddress} won't issue more queries following
delegations than the limit passed to its initializer.
"""
servers = {
('1.1.2.3', 53): {
# First query - force it to start over with a name lookup of
# ns1.example.com
('example.com', A): {
'authority': [('example.com', Record_NS('ns1.example.com'))],
},
# Second query - let it resume the original lookup with the
# address of the nameserver handling the delegation.
('ns1.example.com', A): {
'answers': [('ns1.example.com', Record_A('10.0.0.2'))],
},
},
('10.0.0.2', 53): {
# Third query - let it jump straight to asking the
# delegation server by including its address here (different
# case from the first query).
('example.com', A): {
'authority': [('example.com', Record_NS('ns2.example.com'))],
'additional': [('ns2.example.com', Record_A('10.0.0.3'))],
},
},
('10.0.0.3', 53): {
# Fourth query - give it the answer, we're done.
('example.com', A): {
'answers': [('example.com', Record_A('10.0.0.4'))],
},
},
}
# Make two resolvers. One which is allowed to make 3 queries
# maximum, and so will fail, and on which may make 4, and so should
# succeed.
failer = self._getResolver(servers, 3)
failD = self.assertFailure(
failer.lookupAddress('example.com'), ResolverError)
succeeder = self._getResolver(servers, 4)
succeedD = succeeder.lookupAddress('example.com')
succeedD.addCallback(lambda (ans, auth, add): ans[0].payload)
succeedD.addCallback(self.assertEqual, Record_A('10.0.0.4'))
return gatherResults([failD, succeedD])
def test_discoveredAuthorityDeprecated(self):
"""
Calling L{Resolver.discoveredAuthority} produces a deprecation warning.
"""
resolver = Resolver([])
d = resolver.discoveredAuthority('127.0.0.1', 'example.com', IN, A, (0,))
warnings = self.flushWarnings([
self.test_discoveredAuthorityDeprecated])
self.assertEqual(warnings[0]['category'], DeprecationWarning)
self.assertEqual(
warnings[0]['message'],
'twisted.names.root.Resolver.discoveredAuthority is deprecated since '
'Twisted 10.0. Use twisted.names.client.Resolver directly, instead.')
self.assertEqual(len(warnings), 1)
# This will time out quickly, but we need to wait for it because there
# are resources associated with.
d.addErrback(lambda ignored: None)
return d
class StubDNSDatagramProtocol:
"""
A do-nothing stand-in for L{DNSDatagramProtocol} which can be used to avoid
network traffic in tests where that kind of thing doesn't matter.
"""
def query(self, *a, **kw):
return Deferred()
_retrySuppression = util.suppress(
category=DeprecationWarning,
message=(
'twisted.names.root.retry is deprecated since Twisted 10.0. Use a '
'Resolver object for retry logic.'))
class DiscoveryToolsTests(TestCase):
"""
Tests for the free functions in L{twisted.names.root} which help out with
authority discovery. Since these are mostly deprecated, these are mostly
deprecation tests.
"""
def test_lookupNameserversDeprecated(self):
"""
Calling L{root.lookupNameservers} produces a deprecation warning.
"""
# Don't care about the return value, since it will never have a result,
# since StubDNSDatagramProtocol doesn't actually work.
lookupNameservers('example.com', '127.0.0.1', StubDNSDatagramProtocol())
warnings = self.flushWarnings([
self.test_lookupNameserversDeprecated])
self.assertEqual(warnings[0]['category'], DeprecationWarning)
self.assertEqual(
warnings[0]['message'],
'twisted.names.root.lookupNameservers is deprecated since Twisted '
'10.0. Use twisted.names.root.Resolver.lookupNameservers '
'instead.')
self.assertEqual(len(warnings), 1)
test_lookupNameserversDeprecated.suppress = [_retrySuppression]
def test_lookupAddressDeprecated(self):
"""
Calling L{root.lookupAddress} produces a deprecation warning.
"""
# Don't care about the return value, since it will never have a result,
# since StubDNSDatagramProtocol doesn't actually work.
lookupAddress('example.com', '127.0.0.1', StubDNSDatagramProtocol())
warnings = self.flushWarnings([
self.test_lookupAddressDeprecated])
self.assertEqual(warnings[0]['category'], DeprecationWarning)
self.assertEqual(
warnings[0]['message'],
'twisted.names.root.lookupAddress is deprecated since Twisted '
'10.0. Use twisted.names.root.Resolver.lookupAddress '
'instead.')
self.assertEqual(len(warnings), 1)
test_lookupAddressDeprecated.suppress = [_retrySuppression]
def test_extractAuthorityDeprecated(self):
"""
Calling L{root.extractAuthority} produces a deprecation warning.
"""
extractAuthority(Message(), {})
warnings = self.flushWarnings([
self.test_extractAuthorityDeprecated])
self.assertEqual(warnings[0]['category'], DeprecationWarning)
self.assertEqual(
warnings[0]['message'],
'twisted.names.root.extractAuthority is deprecated since Twisted '
'10.0. Please inspect the Message object directly.')
self.assertEqual(len(warnings), 1)
def test_discoverAuthorityDeprecated(self):
"""
Calling L{root.discoverAuthority} produces a deprecation warning.
"""
discoverAuthority(
'example.com', ['10.0.0.1'], p=StubDNSDatagramProtocol())
warnings = self.flushWarnings([
self.test_discoverAuthorityDeprecated])
self.assertEqual(warnings[0]['category'], DeprecationWarning)
self.assertEqual(
warnings[0]['message'],
'twisted.names.root.discoverAuthority is deprecated since Twisted '
'10.0. Use twisted.names.root.Resolver.lookupNameservers '
'instead.')
self.assertEqual(len(warnings), 1)
# discoverAuthority is implemented in terms of deprecated functions,
# too. Ignore those.
test_discoverAuthorityDeprecated.suppress = [
util.suppress(
category=DeprecationWarning,
message=(
'twisted.names.root.lookupNameservers is deprecated since '
'Twisted 10.0. Use '
'twisted.names.root.Resolver.lookupNameservers instead.')),
_retrySuppression]
def test_retryDeprecated(self):
"""
Calling L{root.retry} produces a deprecation warning.
"""
retry([0], StubDNSDatagramProtocol())
warnings = self.flushWarnings([
self.test_retryDeprecated])
self.assertEqual(warnings[0]['category'], DeprecationWarning)
self.assertEqual(
warnings[0]['message'],
'twisted.names.root.retry is deprecated since Twisted '
'10.0. Use a Resolver object for retry logic.')
self.assertEqual(len(warnings), 1)
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