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# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
import socket
import sys
import unittest
import dns.name
import dns.rdataclass
import dns.rdatatype
import dns.resolver
import tests.util
@unittest.skipIf(not tests.util.is_internet_reachable(), "Internet not reachable")
class OverrideSystemResolverTestCase(unittest.TestCase):
def setUp(self):
self.res = dns.resolver.Resolver(configure=False)
self.res.nameservers = ["8.8.8.8"]
self.res.cache = dns.resolver.LRUCache()
dns.resolver.override_system_resolver(self.res)
def tearDown(self):
dns.resolver.restore_system_resolver()
self.res = None
def test_override(self):
self.assertTrue(socket.getaddrinfo is dns.resolver._getaddrinfo)
socket.gethostbyname("www.dnspython.org")
answer = self.res.cache.get(
(
dns.name.from_text("www.dnspython.org."),
dns.rdatatype.A,
dns.rdataclass.IN,
)
)
self.assertTrue(answer is not None)
self.res.cache.flush()
socket.gethostbyname_ex("www.dnspython.org")
answer = self.res.cache.get(
(
dns.name.from_text("www.dnspython.org."),
dns.rdatatype.A,
dns.rdataclass.IN,
)
)
self.assertTrue(answer is not None)
self.res.cache.flush()
socket.getfqdn("8.8.8.8")
answer = self.res.cache.get(
(
dns.name.from_text("8.8.8.8.in-addr.arpa."),
dns.rdatatype.PTR,
dns.rdataclass.IN,
)
)
self.assertTrue(answer is not None)
self.res.cache.flush()
socket.gethostbyaddr("8.8.8.8")
answer = self.res.cache.get(
(
dns.name.from_text("8.8.8.8.in-addr.arpa."),
dns.rdatatype.PTR,
dns.rdataclass.IN,
)
)
self.assertTrue(answer is not None)
# restoring twice is harmless, so we restore now instead of
# waiting for tearDown so we can assert that it worked
dns.resolver.restore_system_resolver()
self.assertTrue(socket.getaddrinfo is dns.resolver._original_getaddrinfo)
def equivalent_info(self, a, b, q):
if len(a) != len(b):
return False
for x in a:
if x not in b:
# Windows does not set the protocol to non-zero, so try
# looking for a zero protocol.
y = (x[0], x[1], 0, x[3], x[4])
if y not in b:
# musl libc insists on always providing a canonical name, so
# accept that too.
y = (x[0], x[1], x[2], q, x[4])
if y not in b:
print("NOT EQUIVALENT")
print(a)
print(b)
return False
return True
def equivalent(self, *args, **kwargs):
q = args[0]
a = socket.getaddrinfo(*args, **kwargs)
b = dns.resolver._original_getaddrinfo(*args, **kwargs)
return self.equivalent_info(a, b, q)
@unittest.skipIf(
sys.platform == "win32", "avoid windows original getaddrinfo issues"
)
def test_basic_getaddrinfo(self):
self.assertTrue(
self.equivalent("dns.google", 53, socket.AF_INET, socket.SOCK_DGRAM)
)
self.assertTrue(
self.equivalent("dns.google", 53, socket.AF_INET6, socket.SOCK_DGRAM)
)
self.assertTrue(
self.equivalent("dns.google", None, socket.AF_UNSPEC, socket.SOCK_DGRAM)
)
self.assertTrue(
self.equivalent("8.8.8.8", 53, socket.AF_INET, socket.SOCK_DGRAM)
)
self.assertTrue(
self.equivalent(
"2001:4860:4860::8888", 53, socket.AF_INET6, socket.SOCK_DGRAM
)
)
self.assertTrue(
self.equivalent(
"8.8.8.8",
53,
socket.AF_INET,
socket.SOCK_DGRAM,
flags=socket.AI_NUMERICHOST,
)
)
self.assertTrue(
self.equivalent(
"2001:4860:4860::8888",
53,
socket.AF_INET6,
socket.SOCK_DGRAM,
flags=socket.AI_NUMERICHOST,
)
)
def test_getaddrinfo_nxdomain(self):
try:
socket.getaddrinfo("nxdomain.dnspython.org.", 53)
self.assertTrue(False) # should not happen!
except socket.gaierror as e:
self.assertEqual(e.errno, socket.EAI_NONAME)
def test_getaddrinfo_service(self):
a = socket.getaddrinfo("dns.google", "domain")
b = socket.getaddrinfo("dns.google", 53)
self.assertTrue(self.equivalent_info(a, b, "dns.google"))
try:
socket.getaddrinfo("dns.google", "domain", flags=socket.AI_NUMERICSERV)
self.assertTrue(False) # should not happen!
except socket.gaierror as e:
self.assertEqual(e.errno, socket.EAI_NONAME)
def test_getaddrinfo_only_service(self):
infos = socket.getaddrinfo(
service=53,
family=socket.AF_INET,
socktype=socket.SOCK_DGRAM,
proto=socket.IPPROTO_UDP,
)
self.assertEqual(len(infos), 1)
info = infos[0]
self.assertEqual(info[0], socket.AF_INET)
self.assertEqual(info[1], socket.SOCK_DGRAM)
self.assertEqual(info[2], socket.IPPROTO_UDP)
self.assertEqual(info[4], ("127.0.0.1", 53))
def test_unknown_service_fails(self):
with self.assertRaises(socket.gaierror):
socket.getaddrinfo("dns.google.", "bogus-service")
def test_getnameinfo_tcp(self):
info = socket.getnameinfo(("8.8.8.8", 53))
self.assertEqual(info, ("dns.google", "domain"))
def test_getnameinfo_udp(self):
info = socket.getnameinfo(("8.8.8.8", 53), socket.NI_DGRAM)
self.assertEqual(info, ("dns.google", "domain"))
# Give up on testing this for now as all of the names I've considered
# using for testing are part of CDNs and there is deep magic in
# gethostbyaddr() that python's getfqdn() is using. At any rate,
# the problem is that dnspython just gives up whereas the native python
# code is looking up www.dnspython.org, picking a CDN IPv4 address
# (sometimes) and returning the reverse lookup of that address (i.e.
# the domain name of the CDN server). This isn't what I'd consider the
# FQDN of www.dnspython.org to be!
#
# def test_getfqdn(self):
# b = socket.getfqdn('www.dnspython.org')
# # we do this now because python's original getfqdn calls
# # gethostbyaddr() and we don't want it to call us!
# dns.resolver.restore_system_resolver()
# a = dns.resolver._original_getfqdn('www.dnspython.org')
# self.assertEqual(dns.name.from_text(a), dns.name.from_text(b))
def test_gethostbyaddr(self):
a = dns.resolver._original_gethostbyaddr("8.8.8.8")
b = socket.gethostbyaddr("8.8.8.8")
# We only test elements 0 and 2 as we don't set aliases currently!
self.assertEqual(a[0], b[0])
self.assertEqual(a[2], b[2])
a = dns.resolver._original_gethostbyaddr("2001:4860:4860::8888")
b = socket.gethostbyaddr("2001:4860:4860::8888")
self.assertEqual(a[0], b[0])
self.assertEqual(a[2], b[2])
class FakeResolver:
def resolve(self, *args, **kwargs):
raise dns.exception.Timeout
class OverrideSystemResolverUsingFakeResolverTestCase(unittest.TestCase):
def setUp(self):
self.res = FakeResolver()
dns.resolver.override_system_resolver(self.res)
def tearDown(self):
dns.resolver.restore_system_resolver()
self.res = None
def test_temporary_failure(self):
with self.assertRaises(socket.gaierror):
socket.getaddrinfo("dns.google")
# We don't need the fake resolver for the following tests, but we
# don't need the live network either, so we're testing here.
def test_no_host_or_service_fails(self):
with self.assertRaises(socket.gaierror):
socket.getaddrinfo()
def test_AI_ADDRCONFIG_fails(self):
with self.assertRaises(socket.gaierror):
socket.getaddrinfo("dns.google", flags=socket.AI_ADDRCONFIG)
def test_gethostbyaddr_of_name_fails(self):
with self.assertRaises(socket.gaierror):
socket.gethostbyaddr("bogus")
@unittest.skipIf(not tests.util.is_internet_reachable(), "Internet not reachable")
class OverrideSystemResolverUsingDefaultResolverTestCase(unittest.TestCase):
def setUp(self):
self.res = FakeResolver()
dns.resolver.override_system_resolver()
def tearDown(self):
dns.resolver.restore_system_resolver()
self.res = None
def test_override(self):
self.assertEqual(dns.resolver._resolver, dns.resolver.default_resolver)
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