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Diffstat (limited to 'sleekxmpp/xmlstream/resolver.py')
| -rw-r--r-- | sleekxmpp/xmlstream/resolver.py | 333 |
1 files changed, 0 insertions, 333 deletions
diff --git a/sleekxmpp/xmlstream/resolver.py b/sleekxmpp/xmlstream/resolver.py deleted file mode 100644 index 188e5ac7..00000000 --- a/sleekxmpp/xmlstream/resolver.py +++ /dev/null @@ -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 |