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authorFlorent Le Coz <louiz@louiz.org>2014-07-17 14:19:04 +0200
committerFlorent Le Coz <louiz@louiz.org>2014-07-17 14:19:04 +0200
commit5ab77c745270d7d5c016c1dc7ef2a82533a4b16e (patch)
tree259377cc666f8b9c7954fc4e7b8f7a912bcfe101 /sleekxmpp/xmlstream/resolver.py
parente5582694c07236e6830c20361840360a1dde37f3 (diff)
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Rename to slixmpp
Diffstat (limited to 'sleekxmpp/xmlstream/resolver.py')
-rw-r--r--sleekxmpp/xmlstream/resolver.py333
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diff --git a/sleekxmpp/xmlstream/resolver.py b/sleekxmpp/xmlstream/resolver.py
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--- a/sleekxmpp/xmlstream/resolver.py
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@@ -1,333 +0,0 @@
-# -*- encoding: utf-8 -*-
-
-"""
- sleekxmpp.xmlstream.dns
- ~~~~~~~~~~~~~~~~~~~~~~~
-
- :copyright: (c) 2012 Nathanael C. Fritz
- :license: MIT, see LICENSE for more details
-"""
-
-import socket
-import logging
-import random
-
-
-log = logging.getLogger(__name__)
-
-
-#: Global flag indicating the availability of the ``dnspython`` package.
-#: Installing ``dnspython`` can be done via:
-#:
-#: .. code-block:: sh
-#:
-#: pip install dnspython
-#:
-#: For Python3, installation may require installing from source using
-#: the ``python3`` branch:
-#:
-#: .. code-block:: sh
-#:
-#: git clone http://github.com/rthalley/dnspython
-#: cd dnspython
-#: git checkout python3
-#: python3 setup.py install
-DNSPYTHON_AVAILABLE = False
-try:
- import dns.resolver
- DNSPYTHON_AVAILABLE = True
-except ImportError as e:
- log.debug("Could not find dnspython package. " + \
- "Not all features will be available")
-
-
-def default_resolver():
- """Return a basic DNS resolver object.
-
- :returns: A :class:`dns.resolver.Resolver` object if dnspython
- is available. Otherwise, ``None``.
- """
- if DNSPYTHON_AVAILABLE:
- return dns.resolver.get_default_resolver()
- return None
-
-
-def resolve(host, port=None, service=None, proto='tcp',
- resolver=None, use_ipv6=True, use_dnspython=True):
- """Peform DNS resolution for a given hostname.
-
- Resolution may perform SRV record lookups if a service and protocol
- are specified. The returned addresses will be sorted according to
- the SRV priorities and weights.
-
- If no resolver is provided, the dnspython resolver will be used if
- available. Otherwise the built-in socket facilities will be used,
- but those do not provide SRV support.
-
- If SRV records were used, queries to resolve alternative hosts will
- be made as needed instead of all at once.
-
- :param host: The hostname to resolve.
- :param port: A default port to connect with. SRV records may
- dictate use of a different port.
- :param service: Optional SRV service name without leading underscore.
- :param proto: Optional SRV protocol name without leading underscore.
- :param resolver: Optionally provide a DNS resolver object that has
- been custom configured.
- :param use_ipv6: Optionally control the use of IPv6 in situations
- where it is either not available, or performance
- is degraded. Defaults to ``True``.
- :param use_dnspython: Optionally control if dnspython is used to make
- the DNS queries instead of the built-in DNS
- library.
-
- :type host: string
- :type port: int
- :type service: string
- :type proto: string
- :type resolver: :class:`dns.resolver.Resolver`
- :type use_ipv6: bool
- :type use_dnspython: bool
-
- :return: An iterable of IP address, port pairs in the order
- dictated by SRV priorities and weights, if applicable.
- """
-
- if not use_dnspython:
- if DNSPYTHON_AVAILABLE:
- log.debug("DNS: Not using dnspython, but dnspython is installed.")
- else:
- log.debug("DNS: Not using dnspython.")
-
- if not use_ipv6:
- log.debug("DNS: Use of IPv6 has been disabled.")
-
- if resolver is None and DNSPYTHON_AVAILABLE and use_dnspython:
- resolver = dns.resolver.get_default_resolver()
-
- # An IPv6 literal is allowed to be enclosed in square brackets, but
- # the brackets must be stripped in order to process the literal;
- # otherwise, things break.
- host = host.strip('[]')
-
- try:
- # If `host` is an IPv4 literal, we can return it immediately.
- ipv4 = socket.inet_aton(host)
- yield (host, host, port)
- except socket.error:
- pass
-
- if use_ipv6:
- try:
- # Likewise, If `host` is an IPv6 literal, we can return
- # it immediately.
- if hasattr(socket, 'inet_pton'):
- ipv6 = socket.inet_pton(socket.AF_INET6, host)
- yield (host, host, port)
- except (socket.error, ValueError):
- pass
-
- # If no service was provided, then we can just do A/AAAA lookups on the
- # provided host. Otherwise we need to get an ordered list of hosts to
- # resolve based on SRV records.
- if not service:
- hosts = [(host, port)]
- else:
- hosts = get_SRV(host, port, service, proto,
- resolver=resolver,
- use_dnspython=use_dnspython)
-
- for host, port in hosts:
- results = []
- if host == 'localhost':
- if use_ipv6:
- results.append((host, '::1', port))
- results.append((host, '127.0.0.1', port))
- if use_ipv6:
- for address in get_AAAA(host, resolver=resolver,
- use_dnspython=use_dnspython):
- results.append((host, address, port))
- for address in get_A(host, resolver=resolver,
- use_dnspython=use_dnspython):
- results.append((host, address, port))
-
- for host, address, port in results:
- yield host, address, port
-
-
-def get_A(host, resolver=None, use_dnspython=True):
- """Lookup DNS A records for a given host.
-
- If ``resolver`` is not provided, or is ``None``, then resolution will
- be performed using the built-in :mod:`socket` module.
-
- :param host: The hostname to resolve for A record IPv4 addresses.
- :param resolver: Optional DNS resolver object to use for the query.
- :param use_dnspython: Optionally control if dnspython is used to make
- the DNS queries instead of the built-in DNS
- library.
-
- :type host: string
- :type resolver: :class:`dns.resolver.Resolver` or ``None``
- :type use_dnspython: bool
-
- :return: A list of IPv4 literals.
- """
- log.debug("DNS: Querying %s for A records." % host)
-
- # If not using dnspython, attempt lookup using the OS level
- # getaddrinfo() method.
- if resolver is None or not use_dnspython:
- try:
- recs = socket.getaddrinfo(host, None, socket.AF_INET,
- socket.SOCK_STREAM)
- return [rec[4][0] for rec in recs]
- except socket.gaierror:
- log.debug("DNS: Error retreiving A address info for %s." % host)
- return []
-
- # Using dnspython:
- try:
- recs = resolver.query(host, dns.rdatatype.A)
- return [rec.to_text() for rec in recs]
- except (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer):
- log.debug("DNS: No A records for %s" % host)
- return []
- except dns.exception.Timeout:
- log.debug("DNS: A record resolution timed out for %s" % host)
- return []
- except dns.exception.DNSException as e:
- log.debug("DNS: Error querying A records for %s" % host)
- log.exception(e)
- return []
-
-
-def get_AAAA(host, resolver=None, use_dnspython=True):
- """Lookup DNS AAAA records for a given host.
-
- If ``resolver`` is not provided, or is ``None``, then resolution will
- be performed using the built-in :mod:`socket` module.
-
- :param host: The hostname to resolve for AAAA record IPv6 addresses.
- :param resolver: Optional DNS resolver object to use for the query.
- :param use_dnspython: Optionally control if dnspython is used to make
- the DNS queries instead of the built-in DNS
- library.
-
- :type host: string
- :type resolver: :class:`dns.resolver.Resolver` or ``None``
- :type use_dnspython: bool
-
- :return: A list of IPv6 literals.
- """
- log.debug("DNS: Querying %s for AAAA records." % host)
-
- # If not using dnspython, attempt lookup using the OS level
- # getaddrinfo() method.
- if resolver is None or not use_dnspython:
- if not socket.has_ipv6:
- log.debug("Unable to query %s for AAAA records: IPv6 is not supported", host)
- return []
- try:
- recs = socket.getaddrinfo(host, None, socket.AF_INET6,
- socket.SOCK_STREAM)
- return [rec[4][0] for rec in recs]
- except (OSError, socket.gaierror):
- log.debug("DNS: Error retreiving AAAA address " + \
- "info for %s." % host)
- return []
-
- # Using dnspython:
- try:
- recs = resolver.query(host, dns.rdatatype.AAAA)
- return [rec.to_text() for rec in recs]
- except (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer):
- log.debug("DNS: No AAAA records for %s" % host)
- return []
- except dns.exception.Timeout:
- log.debug("DNS: AAAA record resolution timed out for %s" % host)
- return []
- except dns.exception.DNSException as e:
- log.debug("DNS: Error querying AAAA records for %s" % host)
- log.exception(e)
- return []
-
-
-def get_SRV(host, port, service, proto='tcp', resolver=None, use_dnspython=True):
- """Perform SRV record resolution for a given host.
-
- .. note::
-
- This function requires the use of the ``dnspython`` package. Calling
- :func:`get_SRV` without ``dnspython`` will return the provided host
- and port without performing any DNS queries.
-
- :param host: The hostname to resolve.
- :param port: A default port to connect with. SRV records may
- dictate use of a different port.
- :param service: Optional SRV service name without leading underscore.
- :param proto: Optional SRV protocol name without leading underscore.
- :param resolver: Optionally provide a DNS resolver object that has
- been custom configured.
-
- :type host: string
- :type port: int
- :type service: string
- :type proto: string
- :type resolver: :class:`dns.resolver.Resolver`
-
- :return: A list of hostname, port pairs in the order dictacted
- by SRV priorities and weights.
- """
- if resolver is None or not use_dnspython:
- log.warning("DNS: dnspython not found. Can not use SRV lookup.")
- return [(host, port)]
-
- log.debug("DNS: Querying SRV records for %s" % host)
- try:
- recs = resolver.query('_%s._%s.%s' % (service, proto, host),
- dns.rdatatype.SRV)
- except (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer):
- log.debug("DNS: No SRV records for %s." % host)
- return [(host, port)]
- except dns.exception.Timeout:
- log.debug("DNS: SRV record resolution timed out for %s." % host)
- return [(host, port)]
- except dns.exception.DNSException as e:
- log.debug("DNS: Error querying SRV records for %s." % host)
- log.exception(e)
- return [(host, port)]
-
- if len(recs) == 1 and recs[0].target == '.':
- return [(host, port)]
-
- answers = {}
- for rec in recs:
- if rec.priority not in answers:
- answers[rec.priority] = []
- if rec.weight == 0:
- answers[rec.priority].insert(0, rec)
- else:
- answers[rec.priority].append(rec)
-
- sorted_recs = []
- for priority in sorted(answers.keys()):
- while answers[priority]:
- running_sum = 0
- sums = {}
- for rec in answers[priority]:
- running_sum += rec.weight
- sums[running_sum] = rec
-
- selected = random.randint(0, running_sum + 1)
- for running_sum in sums:
- if running_sum >= selected:
- rec = sums[running_sum]
- host = rec.target.to_text()
- if host.endswith('.'):
- host = host[:-1]
- sorted_recs.append((host, rec.port))
- answers[priority].remove(rec)
- break
-
- return sorted_recs