You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 

662 lines
25 KiB

# Copyright (c) 2018 gevent contributors. See LICENSE for details.
# Portions of this code taken from the gogreen project:
# http://github.com/slideinc/gogreen
#
# Copyright (c) 2005-2010 Slide, Inc.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following
# disclaimer in the documentation and/or other materials provided
# with the distribution.
# * Neither the name of the author nor the names of other
# contributors may be used to endorse or promote products derived
# from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
# Portions of this code taken from the eventlet project:
# https://github.com/eventlet/eventlet/blob/master/eventlet/support/greendns.py
# Unless otherwise noted, the files in Eventlet are under the following MIT license:
# Copyright (c) 2005-2006, Bob Ippolito
# Copyright (c) 2007-2010, Linden Research, Inc.
# Copyright (c) 2008-2010, Eventlet Contributors (see AUTHORS)
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
from __future__ import absolute_import, print_function, division
import time
import re
import os
import sys
import _socket
from _socket import AI_NUMERICHOST
from _socket import error
from _socket import NI_NUMERICSERV
from _socket import AF_INET
from _socket import AF_INET6
from _socket import AF_UNSPEC
import socket
from gevent.resolver import AbstractResolver
from gevent.resolver import hostname_types
from gevent._compat import string_types
from gevent._compat import iteritems
from gevent._patcher import import_patched
from gevent._config import config
__all__ = [
'Resolver',
]
# Import the DNS packages to use the gevent modules,
# even if the system is not monkey-patched.
def _patch_dns():
top = import_patched('dns')
for pkg in ('dns',
'dns.rdtypes',
'dns.rdtypes.IN',
'dns.rdtypes.ANY'):
mod = import_patched(pkg)
for name in mod.__all__:
setattr(mod, name, import_patched(pkg + '.' + name))
return top
dns = _patch_dns()
def _dns_import_patched(name):
assert name.startswith('dns')
import_patched(name)
return dns
# This module tries to dynamically import classes
# using __import__, and it's important that they match
# the ones we just created, otherwise exceptions won't be caught
# as expected. It uses a one-arg __import__ statement and then
# tries to walk down the sub-modules using getattr, so we can't
# directly use import_patched as-is.
dns.rdata.__import__ = _dns_import_patched
resolver = dns.resolver
dTimeout = dns.resolver.Timeout
_exc_clear = getattr(sys, 'exc_clear', lambda: None)
# This is a copy of resolver._getaddrinfo with the crucial change that it
# doesn't have a bare except:, because that breaks Timeout and KeyboardInterrupt
# A secondary change is that calls to sys.exc_clear() have been inserted to avoid
# failing tests in test__refcount.py (timeouts).
# See https://github.com/rthalley/dnspython/pull/300
def _getaddrinfo(host=None, service=None, family=AF_UNSPEC, socktype=0,
proto=0, flags=0):
# pylint:disable=too-many-locals,broad-except,too-many-statements
# pylint:disable=too-many-branches
# pylint:disable=redefined-argument-from-local
# pylint:disable=consider-using-in
if flags & (socket.AI_ADDRCONFIG | socket.AI_V4MAPPED) != 0:
raise NotImplementedError
if host is None and service is None:
raise socket.gaierror(socket.EAI_NONAME)
v6addrs = []
v4addrs = []
canonical_name = None
try:
# Is host None or a V6 address literal?
if host is None:
canonical_name = 'localhost'
if flags & socket.AI_PASSIVE != 0:
v6addrs.append('::')
v4addrs.append('0.0.0.0')
else:
v6addrs.append('::1')
v4addrs.append('127.0.0.1')
else:
parts = host.split('%')
if len(parts) == 2:
ahost = parts[0]
else:
ahost = host
addr = dns.ipv6.inet_aton(ahost)
v6addrs.append(host)
canonical_name = host
except Exception:
_exc_clear()
try:
# Is it a V4 address literal?
addr = dns.ipv4.inet_aton(host)
v4addrs.append(host)
canonical_name = host
except Exception:
_exc_clear()
if flags & socket.AI_NUMERICHOST == 0:
try:
if family == socket.AF_INET6 or family == socket.AF_UNSPEC:
v6 = resolver._resolver.query(host, dns.rdatatype.AAAA,
raise_on_no_answer=False)
# Note that setting host ensures we query the same name
# for A as we did for AAAA.
host = v6.qname
canonical_name = v6.canonical_name.to_text(True)
if v6.rrset is not None:
for rdata in v6.rrset:
v6addrs.append(rdata.address)
if family == socket.AF_INET or family == socket.AF_UNSPEC:
v4 = resolver._resolver.query(host, dns.rdatatype.A,
raise_on_no_answer=False)
host = v4.qname
canonical_name = v4.canonical_name.to_text(True)
if v4.rrset is not None:
for rdata in v4.rrset:
v4addrs.append(rdata.address)
except dns.resolver.NXDOMAIN:
_exc_clear()
raise socket.gaierror(socket.EAI_NONAME)
except Exception:
_exc_clear()
raise socket.gaierror(socket.EAI_SYSTEM)
port = None
try:
# Is it a port literal?
if service is None:
port = 0
else:
port = int(service)
except Exception:
_exc_clear()
if flags & socket.AI_NUMERICSERV == 0:
try:
port = socket.getservbyname(service)
except Exception:
_exc_clear()
if port is None:
raise socket.gaierror(socket.EAI_NONAME)
tuples = []
if socktype == 0:
socktypes = [socket.SOCK_DGRAM, socket.SOCK_STREAM]
else:
socktypes = [socktype]
if flags & socket.AI_CANONNAME != 0:
cname = canonical_name
else:
cname = ''
if family == socket.AF_INET6 or family == socket.AF_UNSPEC:
for addr in v6addrs:
for socktype in socktypes:
for proto in resolver._protocols_for_socktype[socktype]:
tuples.append((socket.AF_INET6, socktype, proto,
cname, (addr, port, 0, 0))) # XXX: gevent: this can get the scopeid wrong
if family == socket.AF_INET or family == socket.AF_UNSPEC:
for addr in v4addrs:
for socktype in socktypes:
for proto in resolver._protocols_for_socktype[socktype]:
tuples.append((socket.AF_INET, socktype, proto,
cname, (addr, port)))
if len(tuples) == 0: # pylint:disable=len-as-condition
raise socket.gaierror(socket.EAI_NONAME)
return tuples
resolver._getaddrinfo = _getaddrinfo
HOSTS_TTL = 300.0
def _is_addr(host, parse=dns.ipv4.inet_aton):
if not host:
return False
assert isinstance(host, hostname_types), repr(host)
try:
parse(host)
except dns.exception.SyntaxError:
return False
else:
return True
# Return True if host is a valid IPv4 address
_is_ipv4_addr = _is_addr
def _is_ipv6_addr(host):
# Return True if host is a valid IPv6 address
if host:
s = '%' if isinstance(host, str) else b'%'
host = host.split(s, 1)[0]
return _is_addr(host, dns.ipv6.inet_aton)
class HostsFile(object):
"""
A class to read the contents of a hosts file (/etc/hosts).
"""
LINES_RE = re.compile(r"""
\s* # Leading space
([^\r\n#]+?) # The actual match, non-greedy so as not to include trailing space
\s* # Trailing space
(?:[#][^\r\n]+)? # Comments
(?:$|[\r\n]+) # EOF or newline
""", re.VERBOSE)
def __init__(self, fname=None):
self.v4 = {} # name -> ipv4
self.v6 = {} # name -> ipv6
self.aliases = {} # name -> canonical_name
self.reverse = {} # ip addr -> some name
if fname is None:
if os.name == 'posix':
fname = '/etc/hosts'
elif os.name == 'nt': # pragma: no cover
fname = os.path.expandvars(
r'%SystemRoot%\system32\drivers\etc\hosts')
self.fname = fname
assert self.fname
self._last_load = 0
def _readlines(self):
# Read the contents of the hosts file.
#
# Return list of lines, comment lines and empty lines are
# excluded. Note that this performs disk I/O so can be
# blocking.
with open(self.fname, 'rb') as fp:
fdata = fp.read()
# XXX: Using default decoding. Is that correct?
udata = fdata.decode(errors='ignore') if not isinstance(fdata, str) else fdata
return self.LINES_RE.findall(udata)
def load(self): # pylint:disable=too-many-locals
# Load hosts file
# This will (re)load the data from the hosts
# file if it has changed.
try:
load_time = os.stat(self.fname).st_mtime
needs_load = load_time > self._last_load
except (IOError, OSError):
from gevent import get_hub
get_hub().handle_error(self, *sys.exc_info())
needs_load = False
if not needs_load:
return
v4 = {}
v6 = {}
aliases = {}
reverse = {}
for line in self._readlines():
parts = line.split()
if len(parts) < 2:
continue
ip = parts.pop(0)
if _is_ipv4_addr(ip):
ipmap = v4
elif _is_ipv6_addr(ip):
if ip.startswith('fe80'):
# Do not use link-local addresses, OSX stores these here
continue
ipmap = v6
else:
continue
cname = parts.pop(0).lower()
ipmap[cname] = ip
for alias in parts:
alias = alias.lower()
ipmap[alias] = ip
aliases[alias] = cname
# XXX: This is wrong for ipv6
if ipmap is v4:
ptr = '.'.join(reversed(ip.split('.'))) + '.in-addr.arpa'
else:
ptr = ip + '.ip6.arpa.'
if ptr not in reverse:
reverse[ptr] = cname
self._last_load = load_time
self.v4 = v4
self.v6 = v6
self.aliases = aliases
self.reverse = reverse
def iter_all_host_addr_pairs(self):
self.load()
for name, addr in iteritems(self.v4):
yield name, addr
for name, addr in iteritems(self.v6):
yield name, addr
class _HostsAnswer(dns.resolver.Answer):
# Answer class for HostsResolver object
def __init__(self, qname, rdtype, rdclass, rrset, raise_on_no_answer=True):
self.response = None
self.qname = qname
self.rdtype = rdtype
self.rdclass = rdclass
self.canonical_name = qname
if not rrset and raise_on_no_answer:
raise dns.resolver.NoAnswer()
self.rrset = rrset
self.expiration = (time.time() +
rrset.ttl if hasattr(rrset, 'ttl') else 0)
class _HostsResolver(object):
"""
Class to parse the hosts file
"""
def __init__(self, fname=None, interval=HOSTS_TTL):
self.hosts_file = HostsFile(fname)
self.interval = interval
self._last_load = 0
def query(self, qname, rdtype=dns.rdatatype.A, rdclass=dns.rdataclass.IN,
tcp=False, source=None, raise_on_no_answer=True): # pylint:disable=unused-argument
# Query the hosts file
#
# The known rdtypes are dns.rdatatype.A, dns.rdatatype.AAAA and
# dns.rdatatype.CNAME.
# The ``rdclass`` parameter must be dns.rdataclass.IN while the
# ``tcp`` and ``source`` parameters are ignored.
# Return a HostAnswer instance or raise a dns.resolver.NoAnswer
# exception.
now = time.time()
hosts_file = self.hosts_file
if self._last_load + self.interval < now:
self._last_load = now
hosts_file.load()
rdclass = dns.rdataclass.IN # Always
if isinstance(qname, string_types):
name = qname
qname = dns.name.from_text(qname)
else:
name = str(qname)
name = name.lower()
rrset = dns.rrset.RRset(qname, rdclass, rdtype)
rrset.ttl = self._last_load + self.interval - now
if rdtype == dns.rdatatype.A:
mapping = hosts_file.v4
kind = dns.rdtypes.IN.A.A
elif rdtype == dns.rdatatype.AAAA:
mapping = hosts_file.v6
kind = dns.rdtypes.IN.AAAA.AAAA
elif rdtype == dns.rdatatype.CNAME:
mapping = hosts_file.aliases
kind = lambda c, t, addr: dns.rdtypes.ANY.CNAME.CNAME(c, t, dns.name.from_text(addr))
elif rdtype == dns.rdatatype.PTR:
mapping = hosts_file.reverse
kind = lambda c, t, addr: dns.rdtypes.ANY.PTR.PTR(c, t, dns.name.from_text(addr))
addr = mapping.get(name)
if not addr and qname.is_absolute():
addr = mapping.get(name[:-1])
if addr:
rrset.add(kind(rdclass, rdtype, addr))
return _HostsAnswer(qname, rdtype, rdclass, rrset, raise_on_no_answer)
def getaliases(self, hostname):
# Return a list of all the aliases of a given cname
# Due to the way store aliases this is a bit inefficient, this
# clearly was an afterthought. But this is only used by
# gethostbyname_ex so it's probably fine.
aliases = self.hosts_file.aliases
result = []
if hostname in aliases:
cannon = aliases[hostname]
else:
cannon = hostname
result.append(cannon)
for alias, cname in iteritems(aliases):
if cannon == cname:
result.append(alias)
result.remove(hostname)
return result
class _DualResolver(object):
def __init__(self):
self.hosts_resolver = _HostsResolver()
self.network_resolver = resolver.get_default_resolver()
self.network_resolver.cache = resolver.LRUCache()
def query(self, qname, rdtype=dns.rdatatype.A, rdclass=dns.rdataclass.IN,
tcp=False, source=None, raise_on_no_answer=True,
_hosts_rdtypes=(dns.rdatatype.A, dns.rdatatype.AAAA, dns.rdatatype.PTR)):
# Query the resolver, using /etc/hosts
# Behavior:
# 1. if hosts is enabled and contains answer, return it now
# 2. query nameservers for qname
if qname is None:
qname = '0.0.0.0'
if not isinstance(qname, string_types):
if isinstance(qname, bytes):
qname = qname.decode("idna")
if isinstance(qname, string_types):
qname = dns.name.from_text(qname, None)
if isinstance(rdtype, string_types):
rdtype = dns.rdatatype.from_text(rdtype)
if rdclass == dns.rdataclass.IN and rdtype in _hosts_rdtypes:
try:
answer = self.hosts_resolver.query(qname, rdtype, raise_on_no_answer=False)
except Exception: # pylint: disable=broad-except
from gevent import get_hub
get_hub().handle_error(self, *sys.exc_info())
else:
if answer.rrset:
return answer
return self.network_resolver.query(qname, rdtype, rdclass,
tcp, source, raise_on_no_answer=raise_on_no_answer)
def _family_to_rdtype(family):
if family == socket.AF_INET:
rdtype = dns.rdatatype.A
elif family == socket.AF_INET6:
rdtype = dns.rdatatype.AAAA
else:
raise socket.gaierror(socket.EAI_FAMILY,
'Address family not supported')
return rdtype
class Resolver(AbstractResolver):
"""
An *experimental* resolver that uses `dnspython`_.
This is typically slower than the default threaded resolver
(unless there's a cache hit, in which case it can be much faster).
It is usually much faster than the c-ares resolver. It tends to
scale well as more concurrent resolutions are attempted.
Under Python 2, if the ``idna`` package is installed, this
resolver can resolve Unicode host names that the system resolver
cannot.
.. note::
This **does not** use dnspython's default resolver object, or share any
classes with ``import dns``. A separate copy of the objects is imported to
be able to function in a non monkey-patched process. The documentation for the resolver
object still applies.
The resolver that we use is available as the :attr:`resolver` attribute
of this object (typically ``gevent.get_hub().resolver.resolver``).
.. caution::
Many of the same caveats about DNS results apply here as are documented
for :class:`gevent.resolver.ares.Resolver`.
.. caution::
This resolver is experimental. It may be removed or modified in
the future. As always, feedback is welcome.
.. versionadded:: 1.3a2
.. _dnspython: http://www.dnspython.org
"""
def __init__(self, hub=None): # pylint: disable=unused-argument
if resolver._resolver is None:
_resolver = resolver._resolver = _DualResolver()
if config.resolver_nameservers:
_resolver.network_resolver.nameservers[:] = config.resolver_nameservers
if config.resolver_timeout:
_resolver.network_resolver.lifetime = config.resolver_timeout
# Different hubs in different threads could be sharing the same
# resolver.
assert isinstance(resolver._resolver, _DualResolver)
self._resolver = resolver._resolver
@property
def resolver(self):
"""
The dnspython resolver object we use.
This object has several useful attributes that can be used to
adjust the behaviour of the DNS system:
* ``cache`` is a :class:`dns.resolver.LRUCache`. Its maximum size
can be configured by calling :meth:`resolver.cache.set_max_size`
* ``nameservers`` controls which nameservers to talk to
* ``lifetime`` configures a timeout for each individual query.
"""
return self._resolver.network_resolver
def close(self):
pass
def _getaliases(self, hostname, family):
if not isinstance(hostname, str):
if isinstance(hostname, bytes):
hostname = hostname.decode("idna")
aliases = self._resolver.hosts_resolver.getaliases(hostname)
net_resolver = self._resolver.network_resolver
rdtype = _family_to_rdtype(family)
while True:
try:
ans = net_resolver.query(hostname, dns.rdatatype.CNAME, rdtype)
except (dns.resolver.NoAnswer, dns.resolver.NXDOMAIN, dns.resolver.NoNameservers):
break
except dTimeout:
break
else:
aliases.extend(str(rr.target) for rr in ans.rrset)
hostname = ans[0].target
return aliases
def getaddrinfo(self, host, port, family=0, socktype=0, proto=0, flags=0):
if ((host in (u'localhost', b'localhost')
or (_is_ipv6_addr(host) and host.startswith('fe80')))
or not isinstance(host, str) or (flags & AI_NUMERICHOST)):
# this handles cases which do not require network access
# 1) host is None
# 2) host is of an invalid type
# 3) host is localhost or a link-local ipv6; dnspython returns the wrong
# scope-id for those.
# 3) AI_NUMERICHOST flag is set
return _socket.getaddrinfo(host, port, family, socktype, proto, flags)
if family == AF_UNSPEC:
# This tends to raise in the case that a v6 address did not exist
# but a v4 does. So we break it into two parts.
# Note that if there is no ipv6 in the hosts file, but there *is*
# an ipv4, and there *is* an ipv6 in the nameservers, we will return
# both (from the first call). The system resolver on OS X only returns
# the results from the hosts file. doubleclick.com is one example.
# See also https://github.com/gevent/gevent/issues/1012
try:
return _getaddrinfo(host, port, family, socktype, proto, flags)
except socket.gaierror:
try:
return _getaddrinfo(host, port, AF_INET6, socktype, proto, flags)
except socket.gaierror:
return _getaddrinfo(host, port, AF_INET, socktype, proto, flags)
else:
return _getaddrinfo(host, port, family, socktype, proto, flags)
def getnameinfo(self, sockaddr, flags):
if (sockaddr
and isinstance(sockaddr, (list, tuple))
and sockaddr[0] in ('::1', '127.0.0.1', 'localhost')):
return _socket.getnameinfo(sockaddr, flags)
if isinstance(sockaddr, (list, tuple)) and not isinstance(sockaddr[0], hostname_types):
raise TypeError("getnameinfo(): illegal sockaddr argument")
try:
return resolver._getnameinfo(sockaddr, flags)
except error:
if not flags:
# dnspython doesn't like getting ports it can't resolve.
# We have one test, test__socket_dns.py:Test_getnameinfo_geventorg.test_port_zero
# that does this. We conservatively fix it here; this could be expanded later.
return resolver._getnameinfo(sockaddr, NI_NUMERICSERV)
def gethostbyaddr(self, ip_address):
if ip_address in (u'127.0.0.1', u'::1',
b'127.0.0.1', b'::1',
'localhost'):
return _socket.gethostbyaddr(ip_address)
if not isinstance(ip_address, hostname_types):
raise TypeError("argument 1 must be str, bytes or bytearray, not %s" % (type(ip_address),))
return resolver._gethostbyaddr(ip_address)