+++ /dev/null
-# Copyright (C) 2003-2007, 2009-2011 Nominum, Inc.
-#
-# Permission to use, copy, modify, and distribute this software and its
-# documentation for any purpose with or without fee is hereby granted,
-# provided that the above copyright notice and this permission notice
-# appear in all copies.
-#
-# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
-# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
-# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
-# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-
-"""DNS stub resolver.
-
-@var default_resolver: The default resolver object
-@type default_resolver: dns.resolver.Resolver object"""
-
-import socket
-import sys
-import time
-
-import dns.exception
-import dns.ipv4
-import dns.ipv6
-import dns.message
-import dns.name
-import dns.query
-import dns.rcode
-import dns.rdataclass
-import dns.rdatatype
-import dns.reversename
-
-if sys.platform == 'win32':
- import _winreg
-
-class NXDOMAIN(dns.exception.DNSException):
- """The query name does not exist."""
- pass
-
-# The definition of the Timeout exception has moved from here to the
-# dns.exception module. We keep dns.resolver.Timeout defined for
-# backwards compatibility.
-
-Timeout = dns.exception.Timeout
-
-class NoAnswer(dns.exception.DNSException):
- """The response did not contain an answer to the question."""
- pass
-
-class NoNameservers(dns.exception.DNSException):
- """No non-broken nameservers are available to answer the query."""
- pass
-
-class NotAbsolute(dns.exception.DNSException):
- """Raised if an absolute domain name is required but a relative name
- was provided."""
- pass
-
-class NoRootSOA(dns.exception.DNSException):
- """Raised if for some reason there is no SOA at the root name.
- This should never happen!"""
- pass
-
-class NoMetaqueries(dns.exception.DNSException):
- """Metaqueries are not allowed."""
- pass
-
-
-class Answer(object):
- """DNS stub resolver answer
-
- Instances of this class bundle up the result of a successful DNS
- resolution.
-
- For convenience, the answer object implements much of the sequence
- protocol, forwarding to its rrset. E.g. "for a in answer" is
- equivalent to "for a in answer.rrset", "answer[i]" is equivalent
- to "answer.rrset[i]", and "answer[i:j]" is equivalent to
- "answer.rrset[i:j]".
-
- Note that CNAMEs or DNAMEs in the response may mean that answer
- node's name might not be the query name.
-
- @ivar qname: The query name
- @type qname: dns.name.Name object
- @ivar rdtype: The query type
- @type rdtype: int
- @ivar rdclass: The query class
- @type rdclass: int
- @ivar response: The response message
- @type response: dns.message.Message object
- @ivar rrset: The answer
- @type rrset: dns.rrset.RRset object
- @ivar expiration: The time when the answer expires
- @type expiration: float (seconds since the epoch)
- @ivar canonical_name: The canonical name of the query name
- @type canonical_name: dns.name.Name object
- """
- def __init__(self, qname, rdtype, rdclass, response,
- raise_on_no_answer=True):
- self.qname = qname
- self.rdtype = rdtype
- self.rdclass = rdclass
- self.response = response
- min_ttl = -1
- rrset = None
- for count in xrange(0, 15):
- try:
- rrset = response.find_rrset(response.answer, qname,
- rdclass, rdtype)
- if min_ttl == -1 or rrset.ttl < min_ttl:
- min_ttl = rrset.ttl
- break
- except KeyError:
- if rdtype != dns.rdatatype.CNAME:
- try:
- crrset = response.find_rrset(response.answer,
- qname,
- rdclass,
- dns.rdatatype.CNAME)
- if min_ttl == -1 or crrset.ttl < min_ttl:
- min_ttl = crrset.ttl
- for rd in crrset:
- qname = rd.target
- break
- continue
- except KeyError:
- if raise_on_no_answer:
- raise NoAnswer
- if raise_on_no_answer:
- raise NoAnswer
- if rrset is None and raise_on_no_answer:
- raise NoAnswer
- self.canonical_name = qname
- self.rrset = rrset
- if rrset is None:
- while 1:
- # Look for a SOA RR whose owner name is a superdomain
- # of qname.
- try:
- srrset = response.find_rrset(response.authority, qname,
- rdclass, dns.rdatatype.SOA)
- if min_ttl == -1 or srrset.ttl < min_ttl:
- min_ttl = srrset.ttl
- if srrset[0].minimum < min_ttl:
- min_ttl = srrset[0].minimum
- break
- except KeyError:
- try:
- qname = qname.parent()
- except dns.name.NoParent:
- break
- self.expiration = time.time() + min_ttl
-
- def __getattr__(self, attr):
- if attr == 'name':
- return self.rrset.name
- elif attr == 'ttl':
- return self.rrset.ttl
- elif attr == 'covers':
- return self.rrset.covers
- elif attr == 'rdclass':
- return self.rrset.rdclass
- elif attr == 'rdtype':
- return self.rrset.rdtype
- else:
- raise AttributeError(attr)
-
- def __len__(self):
- return len(self.rrset)
-
- def __iter__(self):
- return iter(self.rrset)
-
- def __getitem__(self, i):
- return self.rrset[i]
-
- def __delitem__(self, i):
- del self.rrset[i]
-
- def __getslice__(self, i, j):
- return self.rrset[i:j]
-
- def __delslice__(self, i, j):
- del self.rrset[i:j]
-
-class Cache(object):
- """Simple DNS answer cache.
-
- @ivar data: A dictionary of cached data
- @type data: dict
- @ivar cleaning_interval: The number of seconds between cleanings. The
- default is 300 (5 minutes).
- @type cleaning_interval: float
- @ivar next_cleaning: The time the cache should next be cleaned (in seconds
- since the epoch.)
- @type next_cleaning: float
- """
-
- def __init__(self, cleaning_interval=300.0):
- """Initialize a DNS cache.
-
- @param cleaning_interval: the number of seconds between periodic
- cleanings. The default is 300.0
- @type cleaning_interval: float.
- """
-
- self.data = {}
- self.cleaning_interval = cleaning_interval
- self.next_cleaning = time.time() + self.cleaning_interval
-
- def maybe_clean(self):
- """Clean the cache if it's time to do so."""
-
- now = time.time()
- if self.next_cleaning <= now:
- keys_to_delete = []
- for (k, v) in self.data.iteritems():
- if v.expiration <= now:
- keys_to_delete.append(k)
- for k in keys_to_delete:
- del self.data[k]
- now = time.time()
- self.next_cleaning = now + self.cleaning_interval
-
- def get(self, key):
- """Get the answer associated with I{key}. Returns None if
- no answer is cached for the key.
- @param key: the key
- @type key: (dns.name.Name, int, int) tuple whose values are the
- query name, rdtype, and rdclass.
- @rtype: dns.resolver.Answer object or None
- """
-
- self.maybe_clean()
- v = self.data.get(key)
- if v is None or v.expiration <= time.time():
- return None
- return v
-
- def put(self, key, value):
- """Associate key and value in the cache.
- @param key: the key
- @type key: (dns.name.Name, int, int) tuple whose values are the
- query name, rdtype, and rdclass.
- @param value: The answer being cached
- @type value: dns.resolver.Answer object
- """
-
- self.maybe_clean()
- self.data[key] = value
-
- def flush(self, key=None):
- """Flush the cache.
-
- If I{key} is specified, only that item is flushed. Otherwise
- the entire cache is flushed.
-
- @param key: the key to flush
- @type key: (dns.name.Name, int, int) tuple or None
- """
-
- if not key is None:
- if self.data.has_key(key):
- del self.data[key]
- else:
- self.data = {}
- self.next_cleaning = time.time() + self.cleaning_interval
-
-class LRUCacheNode(object):
- """LRUCache node.
- """
- def __init__(self, key, value):
- self.key = key
- self.value = value
- self.prev = self
- self.next = self
-
- def link_before(self, node):
- self.prev = node.prev
- self.next = node
- node.prev.next = self
- node.prev = self
-
- def link_after(self, node):
- self.prev = node
- self.next = node.next
- node.next.prev = self
- node.next = self
-
- def unlink(self):
- self.next.prev = self.prev
- self.prev.next = self.next
-
-class LRUCache(object):
- """Bounded least-recently-used DNS answer cache.
-
- This cache is better than the simple cache (above) if you're
- running a web crawler or other process that does a lot of
- resolutions. The LRUCache has a maximum number of nodes, and when
- it is full, the least-recently used node is removed to make space
- for a new one.
-
- @ivar data: A dictionary of cached data
- @type data: dict
- @ivar sentinel: sentinel node for circular doubly linked list of nodes
- @type sentinel: LRUCacheNode object
- @ivar max_size: The maximum number of nodes
- @type max_size: int
- """
-
- def __init__(self, max_size=100000):
- """Initialize a DNS cache.
-
- @param max_size: The maximum number of nodes to cache; the default is
- 100000. Must be > 1.
- @type max_size: int
- """
- self.data = {}
- self.set_max_size(max_size)
- self.sentinel = LRUCacheNode(None, None)
-
- def set_max_size(self, max_size):
- if max_size < 1:
- max_size = 1
- self.max_size = max_size
-
- def get(self, key):
- """Get the answer associated with I{key}. Returns None if
- no answer is cached for the key.
- @param key: the key
- @type key: (dns.name.Name, int, int) tuple whose values are the
- query name, rdtype, and rdclass.
- @rtype: dns.resolver.Answer object or None
- """
- node = self.data.get(key)
- if node is None:
- return None
- # Unlink because we're either going to move the node to the front
- # of the LRU list or we're going to free it.
- node.unlink()
- if node.value.expiration <= time.time():
- del self.data[node.key]
- return None
- node.link_after(self.sentinel)
- return node.value
-
- def put(self, key, value):
- """Associate key and value in the cache.
- @param key: the key
- @type key: (dns.name.Name, int, int) tuple whose values are the
- query name, rdtype, and rdclass.
- @param value: The answer being cached
- @type value: dns.resolver.Answer object
- """
- node = self.data.get(key)
- if not node is None:
- node.unlink()
- del self.data[node.key]
- while len(self.data) >= self.max_size:
- node = self.sentinel.prev
- node.unlink()
- del self.data[node.key]
- node = LRUCacheNode(key, value)
- node.link_after(self.sentinel)
- self.data[key] = node
-
- def flush(self, key=None):
- """Flush the cache.
-
- If I{key} is specified, only that item is flushed. Otherwise
- the entire cache is flushed.
-
- @param key: the key to flush
- @type key: (dns.name.Name, int, int) tuple or None
- """
- if not key is None:
- node = self.data.get(key)
- if not node is None:
- node.unlink()
- del self.data[node.key]
- else:
- node = self.sentinel.next
- while node != self.sentinel:
- next = node.next
- node.prev = None
- node.next = None
- node = next
- self.data = {}
-
-class Resolver(object):
- """DNS stub resolver
-
- @ivar domain: The domain of this host
- @type domain: dns.name.Name object
- @ivar nameservers: A list of nameservers to query. Each nameserver is
- a string which contains the IP address of a nameserver.
- @type nameservers: list of strings
- @ivar search: The search list. If the query name is a relative name,
- the resolver will construct an absolute query name by appending the search
- names one by one to the query name.
- @type search: list of dns.name.Name objects
- @ivar port: The port to which to send queries. The default is 53.
- @type port: int
- @ivar timeout: The number of seconds to wait for a response from a
- server, before timing out.
- @type timeout: float
- @ivar lifetime: The total number of seconds to spend trying to get an
- answer to the question. If the lifetime expires, a Timeout exception
- will occur.
- @type lifetime: float
- @ivar keyring: The TSIG keyring to use. The default is None.
- @type keyring: dict
- @ivar keyname: The TSIG keyname to use. The default is None.
- @type keyname: dns.name.Name object
- @ivar keyalgorithm: The TSIG key algorithm to use. The default is
- dns.tsig.default_algorithm.
- @type keyalgorithm: string
- @ivar edns: The EDNS level to use. The default is -1, no Edns.
- @type edns: int
- @ivar ednsflags: The EDNS flags
- @type ednsflags: int
- @ivar payload: The EDNS payload size. The default is 0.
- @type payload: int
- @ivar cache: The cache to use. The default is None.
- @type cache: dns.resolver.Cache object
- """
- def __init__(self, filename='/etc/resolv.conf', configure=True):
- """Initialize a resolver instance.
-
- @param filename: The filename of a configuration file in
- standard /etc/resolv.conf format. This parameter is meaningful
- only when I{configure} is true and the platform is POSIX.
- @type filename: string or file object
- @param configure: If True (the default), the resolver instance
- is configured in the normal fashion for the operating system
- the resolver is running on. (I.e. a /etc/resolv.conf file on
- POSIX systems and from the registry on Windows systems.)
- @type configure: bool"""
-
- self.reset()
- if configure:
- if sys.platform == 'win32':
- self.read_registry()
- elif filename:
- self.read_resolv_conf(filename)
-
- def reset(self):
- """Reset all resolver configuration to the defaults."""
- self.domain = \
- dns.name.Name(dns.name.from_text(socket.gethostname())[1:])
- if len(self.domain) == 0:
- self.domain = dns.name.root
- self.nameservers = []
- self.search = []
- self.port = 53
- self.timeout = 2.0
- self.lifetime = 30.0
- self.keyring = None
- self.keyname = None
- self.keyalgorithm = dns.tsig.default_algorithm
- self.edns = -1
- self.ednsflags = 0
- self.payload = 0
- self.cache = None
-
- def read_resolv_conf(self, f):
- """Process f as a file in the /etc/resolv.conf format. If f is
- a string, it is used as the name of the file to open; otherwise it
- is treated as the file itself."""
- if isinstance(f, str) or isinstance(f, unicode):
- try:
- f = open(f, 'r')
- except IOError:
- # /etc/resolv.conf doesn't exist, can't be read, etc.
- # We'll just use the default resolver configuration.
- self.nameservers = ['127.0.0.1']
- return
- want_close = True
- else:
- want_close = False
- try:
- for l in f:
- if len(l) == 0 or l[0] == '#' or l[0] == ';':
- continue
- tokens = l.split()
- if len(tokens) == 0:
- continue
- if tokens[0] == 'nameserver':
- self.nameservers.append(tokens[1])
- elif tokens[0] == 'domain':
- self.domain = dns.name.from_text(tokens[1])
- elif tokens[0] == 'search':
- for suffix in tokens[1:]:
- self.search.append(dns.name.from_text(suffix))
- finally:
- if want_close:
- f.close()
- if len(self.nameservers) == 0:
- self.nameservers.append('127.0.0.1')
-
- def _determine_split_char(self, entry):
- #
- # The windows registry irritatingly changes the list element
- # delimiter in between ' ' and ',' (and vice-versa) in various
- # versions of windows.
- #
- if entry.find(' ') >= 0:
- split_char = ' '
- elif entry.find(',') >= 0:
- split_char = ','
- else:
- # probably a singleton; treat as a space-separated list.
- split_char = ' '
- return split_char
-
- def _config_win32_nameservers(self, nameservers):
- """Configure a NameServer registry entry."""
- # we call str() on nameservers to convert it from unicode to ascii
- nameservers = str(nameservers)
- split_char = self._determine_split_char(nameservers)
- ns_list = nameservers.split(split_char)
- for ns in ns_list:
- if not ns in self.nameservers:
- self.nameservers.append(ns)
-
- def _config_win32_domain(self, domain):
- """Configure a Domain registry entry."""
- # we call str() on domain to convert it from unicode to ascii
- self.domain = dns.name.from_text(str(domain))
-
- def _config_win32_search(self, search):
- """Configure a Search registry entry."""
- # we call str() on search to convert it from unicode to ascii
- search = str(search)
- split_char = self._determine_split_char(search)
- search_list = search.split(split_char)
- for s in search_list:
- if not s in self.search:
- self.search.append(dns.name.from_text(s))
-
- def _config_win32_fromkey(self, key):
- """Extract DNS info from a registry key."""
- try:
- servers, rtype = _winreg.QueryValueEx(key, 'NameServer')
- except WindowsError:
- servers = None
- if servers:
- self._config_win32_nameservers(servers)
- try:
- dom, rtype = _winreg.QueryValueEx(key, 'Domain')
- if dom:
- self._config_win32_domain(dom)
- except WindowsError:
- pass
- else:
- try:
- servers, rtype = _winreg.QueryValueEx(key, 'DhcpNameServer')
- except WindowsError:
- servers = None
- if servers:
- self._config_win32_nameservers(servers)
- try:
- dom, rtype = _winreg.QueryValueEx(key, 'DhcpDomain')
- if dom:
- self._config_win32_domain(dom)
- except WindowsError:
- pass
- try:
- search, rtype = _winreg.QueryValueEx(key, 'SearchList')
- except WindowsError:
- search = None
- if search:
- self._config_win32_search(search)
-
- def read_registry(self):
- """Extract resolver configuration from the Windows registry."""
- lm = _winreg.ConnectRegistry(None, _winreg.HKEY_LOCAL_MACHINE)
- want_scan = False
- try:
- try:
- # XP, 2000
- tcp_params = _winreg.OpenKey(lm,
- r'SYSTEM\CurrentControlSet'
- r'\Services\Tcpip\Parameters')
- want_scan = True
- except EnvironmentError:
- # ME
- tcp_params = _winreg.OpenKey(lm,
- r'SYSTEM\CurrentControlSet'
- r'\Services\VxD\MSTCP')
- try:
- self._config_win32_fromkey(tcp_params)
- finally:
- tcp_params.Close()
- if want_scan:
- interfaces = _winreg.OpenKey(lm,
- r'SYSTEM\CurrentControlSet'
- r'\Services\Tcpip\Parameters'
- r'\Interfaces')
- try:
- i = 0
- while True:
- try:
- guid = _winreg.EnumKey(interfaces, i)
- i += 1
- key = _winreg.OpenKey(interfaces, guid)
- if not self._win32_is_nic_enabled(lm, guid, key):
- continue
- try:
- self._config_win32_fromkey(key)
- finally:
- key.Close()
- except EnvironmentError:
- break
- finally:
- interfaces.Close()
- finally:
- lm.Close()
-
- def _win32_is_nic_enabled(self, lm, guid, interface_key):
- # Look in the Windows Registry to determine whether the network
- # interface corresponding to the given guid is enabled.
- #
- # (Code contributed by Paul Marks, thanks!)
- #
- try:
- # This hard-coded location seems to be consistent, at least
- # from Windows 2000 through Vista.
- connection_key = _winreg.OpenKey(
- lm,
- r'SYSTEM\CurrentControlSet\Control\Network'
- r'\{4D36E972-E325-11CE-BFC1-08002BE10318}'
- r'\%s\Connection' % guid)
-
- try:
- # The PnpInstanceID points to a key inside Enum
- (pnp_id, ttype) = _winreg.QueryValueEx(
- connection_key, 'PnpInstanceID')
-
- if ttype != _winreg.REG_SZ:
- raise ValueError
-
- device_key = _winreg.OpenKey(
- lm, r'SYSTEM\CurrentControlSet\Enum\%s' % pnp_id)
-
- try:
- # Get ConfigFlags for this device
- (flags, ttype) = _winreg.QueryValueEx(
- device_key, 'ConfigFlags')
-
- if ttype != _winreg.REG_DWORD:
- raise ValueError
-
- # Based on experimentation, bit 0x1 indicates that the
- # device is disabled.
- return not (flags & 0x1)
-
- finally:
- device_key.Close()
- finally:
- connection_key.Close()
- except (EnvironmentError, ValueError):
- # Pre-vista, enabled interfaces seem to have a non-empty
- # NTEContextList; this was how dnspython detected enabled
- # nics before the code above was contributed. We've retained
- # the old method since we don't know if the code above works
- # on Windows 95/98/ME.
- try:
- (nte, ttype) = _winreg.QueryValueEx(interface_key,
- 'NTEContextList')
- return nte is not None
- except WindowsError:
- return False
-
- def _compute_timeout(self, start):
- now = time.time()
- if now < start:
- if start - now > 1:
- # Time going backwards is bad. Just give up.
- raise Timeout
- else:
- # Time went backwards, but only a little. This can
- # happen, e.g. under vmware with older linux kernels.
- # Pretend it didn't happen.
- now = start
- duration = now - start
- if duration >= self.lifetime:
- raise Timeout
- return min(self.lifetime - duration, self.timeout)
-
- def query(self, qname, rdtype=dns.rdatatype.A, rdclass=dns.rdataclass.IN,
- tcp=False, source=None, raise_on_no_answer=True):
- """Query nameservers to find the answer to the question.
-
- The I{qname}, I{rdtype}, and I{rdclass} parameters may be objects
- of the appropriate type, or strings that can be converted into objects
- of the appropriate type. E.g. For I{rdtype} the integer 2 and the
- the string 'NS' both mean to query for records with DNS rdata type NS.
-
- @param qname: the query name
- @type qname: dns.name.Name object or string
- @param rdtype: the query type
- @type rdtype: int or string
- @param rdclass: the query class
- @type rdclass: int or string
- @param tcp: use TCP to make the query (default is False).
- @type tcp: bool
- @param source: bind to this IP address (defaults to machine default IP).
- @type source: IP address in dotted quad notation
- @param raise_on_no_answer: raise NoAnswer if there's no answer
- (defaults is True).
- @type raise_on_no_answer: bool
- @rtype: dns.resolver.Answer instance
- @raises Timeout: no answers could be found in the specified lifetime
- @raises NXDOMAIN: the query name does not exist
- @raises NoAnswer: the response did not contain an answer and
- raise_on_no_answer is True.
- @raises NoNameservers: no non-broken nameservers are available to
- answer the question."""
-
- if isinstance(qname, (str, unicode)):
- qname = dns.name.from_text(qname, None)
- if isinstance(rdtype, (str, unicode)):
- rdtype = dns.rdatatype.from_text(rdtype)
- if dns.rdatatype.is_metatype(rdtype):
- raise NoMetaqueries
- if isinstance(rdclass, (str, unicode)):
- rdclass = dns.rdataclass.from_text(rdclass)
- if dns.rdataclass.is_metaclass(rdclass):
- raise NoMetaqueries
- qnames_to_try = []
- if qname.is_absolute():
- qnames_to_try.append(qname)
- else:
- if len(qname) > 1:
- qnames_to_try.append(qname.concatenate(dns.name.root))
- if self.search:
- for suffix in self.search:
- qnames_to_try.append(qname.concatenate(suffix))
- else:
- qnames_to_try.append(qname.concatenate(self.domain))
- all_nxdomain = True
- start = time.time()
- for qname in qnames_to_try:
- if self.cache:
- answer = self.cache.get((qname, rdtype, rdclass))
- if not answer is None:
- if answer.rrset is None and raise_on_no_answer:
- raise NoAnswer
- else:
- return answer
- request = dns.message.make_query(qname, rdtype, rdclass)
- if not self.keyname is None:
- request.use_tsig(self.keyring, self.keyname,
- algorithm=self.keyalgorithm)
- request.use_edns(self.edns, self.ednsflags, self.payload)
- response = None
- #
- # make a copy of the servers list so we can alter it later.
- #
- nameservers = self.nameservers[:]
- backoff = 0.10
- while response is None:
- if len(nameservers) == 0:
- raise NoNameservers
- for nameserver in nameservers[:]:
- timeout = self._compute_timeout(start)
- try:
- if tcp:
- response = dns.query.tcp(request, nameserver,
- timeout, self.port,
- source=source)
- else:
- response = dns.query.udp(request, nameserver,
- timeout, self.port,
- source=source)
- except (socket.error, dns.exception.Timeout):
- #
- # Communication failure or timeout. Go to the
- # next server
- #
- response = None
- continue
- except dns.query.UnexpectedSource:
- #
- # Who knows? Keep going.
- #
- response = None
- continue
- except dns.exception.FormError:
- #
- # We don't understand what this server is
- # saying. Take it out of the mix and
- # continue.
- #
- nameservers.remove(nameserver)
- response = None
- continue
- rcode = response.rcode()
- if rcode == dns.rcode.NOERROR or \
- rcode == dns.rcode.NXDOMAIN:
- break
- #
- # We got a response, but we're not happy with the
- # rcode in it. Remove the server from the mix if
- # the rcode isn't SERVFAIL.
- #
- if rcode != dns.rcode.SERVFAIL:
- nameservers.remove(nameserver)
- response = None
- if not response is None:
- break
- #
- # All nameservers failed!
- #
- if len(nameservers) > 0:
- #
- # But we still have servers to try. Sleep a bit
- # so we don't pound them!
- #
- timeout = self._compute_timeout(start)
- sleep_time = min(timeout, backoff)
- backoff *= 2
- time.sleep(sleep_time)
- if response.rcode() == dns.rcode.NXDOMAIN:
- continue
- all_nxdomain = False
- break
- if all_nxdomain:
- raise NXDOMAIN
- answer = Answer(qname, rdtype, rdclass, response,
- raise_on_no_answer)
- if self.cache:
- self.cache.put((qname, rdtype, rdclass), answer)
- return answer
-
- def use_tsig(self, keyring, keyname=None,
- algorithm=dns.tsig.default_algorithm):
- """Add a TSIG signature to the query.
-
- @param keyring: The TSIG keyring to use; defaults to None.
- @type keyring: dict
- @param keyname: The name of the TSIG key to use; defaults to None.
- The key must be defined in the keyring. If a keyring is specified
- but a keyname is not, then the key used will be the first key in the
- keyring. Note that the order of keys in a dictionary is not defined,
- so applications should supply a keyname when a keyring is used, unless
- they know the keyring contains only one key.
- @param algorithm: The TSIG key algorithm to use. The default
- is dns.tsig.default_algorithm.
- @type algorithm: string"""
- self.keyring = keyring
- if keyname is None:
- self.keyname = self.keyring.keys()[0]
- else:
- self.keyname = keyname
- self.keyalgorithm = algorithm
-
- def use_edns(self, edns, ednsflags, payload):
- """Configure Edns.
-
- @param edns: The EDNS level to use. The default is -1, no Edns.
- @type edns: int
- @param ednsflags: The EDNS flags
- @type ednsflags: int
- @param payload: The EDNS payload size. The default is 0.
- @type payload: int"""
-
- if edns is None:
- edns = -1
- self.edns = edns
- self.ednsflags = ednsflags
- self.payload = payload
-
-default_resolver = None
-
-def get_default_resolver():
- """Get the default resolver, initializing it if necessary."""
- global default_resolver
- if default_resolver is None:
- default_resolver = Resolver()
- return default_resolver
-
-def query(qname, rdtype=dns.rdatatype.A, rdclass=dns.rdataclass.IN,
- tcp=False, source=None, raise_on_no_answer=True):
- """Query nameservers to find the answer to the question.
-
- This is a convenience function that uses the default resolver
- object to make the query.
- @see: L{dns.resolver.Resolver.query} for more information on the
- parameters."""
- return get_default_resolver().query(qname, rdtype, rdclass, tcp, source,
- raise_on_no_answer)
-
-def zone_for_name(name, rdclass=dns.rdataclass.IN, tcp=False, resolver=None):
- """Find the name of the zone which contains the specified name.
-
- @param name: the query name
- @type name: absolute dns.name.Name object or string
- @param rdclass: The query class
- @type rdclass: int
- @param tcp: use TCP to make the query (default is False).
- @type tcp: bool
- @param resolver: the resolver to use
- @type resolver: dns.resolver.Resolver object or None
- @rtype: dns.name.Name"""
-
- if isinstance(name, (str, unicode)):
- name = dns.name.from_text(name, dns.name.root)
- if resolver is None:
- resolver = get_default_resolver()
- if not name.is_absolute():
- raise NotAbsolute(name)
- while 1:
- try:
- answer = resolver.query(name, dns.rdatatype.SOA, rdclass, tcp)
- if answer.rrset.name == name:
- return name
- # otherwise we were CNAMEd or DNAMEd and need to look higher
- except (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer):
- pass
- try:
- name = name.parent()
- except dns.name.NoParent:
- raise NoRootSOA
-
-#
-# Support for overriding the system resolver for all python code in the
-# running process.
-#
-
-_protocols_for_socktype = {
- socket.SOCK_DGRAM : [socket.SOL_UDP],
- socket.SOCK_STREAM : [socket.SOL_TCP],
- }
-
-_resolver = None
-_original_getaddrinfo = socket.getaddrinfo
-_original_getnameinfo = socket.getnameinfo
-_original_getfqdn = socket.getfqdn
-_original_gethostbyname = socket.gethostbyname
-_original_gethostbyname_ex = socket.gethostbyname_ex
-_original_gethostbyaddr = socket.gethostbyaddr
-
-def _getaddrinfo(host=None, service=None, family=socket.AF_UNSPEC, socktype=0,
- proto=0, flags=0):
- 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:
- try:
- # Is it a V4 address literal?
- addr = dns.ipv4.inet_aton(host)
- v4addrs.append(host)
- canonical_name = host
- except:
- if flags & socket.AI_NUMERICHOST == 0:
- try:
- qname = None
- if family == socket.AF_INET6 or family == socket.AF_UNSPEC:
- v6 = _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.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:
- raise socket.gaierror(socket.EAI_NONAME)
- except:
- 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:
- if flags & socket.AI_NUMERICSERV == 0:
- try:
- port = socket.getservbyname(service)
- except:
- pass
- 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 _protocols_for_socktype[socktype]:
- tuples.append((socket.AF_INET6, socktype, proto,
- cname, (addr, port, 0, 0)))
- if family == socket.AF_INET or family == socket.AF_UNSPEC:
- for addr in v4addrs:
- for socktype in socktypes:
- for proto in _protocols_for_socktype[socktype]:
- tuples.append((socket.AF_INET, socktype, proto,
- cname, (addr, port)))
- if len(tuples) == 0:
- raise socket.gaierror(socket.EAI_NONAME)
- return tuples
-
-def _getnameinfo(sockaddr, flags=0):
- host = sockaddr[0]
- port = sockaddr[1]
- if len(sockaddr) == 4:
- scope = sockaddr[3]
- family = socket.AF_INET6
- else:
- scope = None
- family = socket.AF_INET
- tuples = _getaddrinfo(host, port, family, socket.SOCK_STREAM,
- socket.SOL_TCP, 0)
- if len(tuples) > 1:
- raise socket.error('sockaddr resolved to multiple addresses')
- addr = tuples[0][4][0]
- if flags & socket.NI_DGRAM:
- pname = 'udp'
- else:
- pname = 'tcp'
- qname = dns.reversename.from_address(addr)
- if flags & socket.NI_NUMERICHOST == 0:
- try:
- answer = _resolver.query(qname, 'PTR')
- hostname = answer.rrset[0].target.to_text(True)
- except (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer):
- if flags & socket.NI_NAMEREQD:
- raise socket.gaierror(socket.EAI_NONAME)
- hostname = addr
- if scope is not None:
- hostname += '%' + str(scope)
- else:
- hostname = addr
- if scope is not None:
- hostname += '%' + str(scope)
- if flags & socket.NI_NUMERICSERV:
- service = str(port)
- else:
- service = socket.getservbyport(port, pname)
- return (hostname, service)
-
-def _getfqdn(name=None):
- if name is None:
- name = socket.gethostname()
- return _getnameinfo(_getaddrinfo(name, 80)[0][4])[0]
-
-def _gethostbyname(name):
- return _gethostbyname_ex(name)[2][0]
-
-def _gethostbyname_ex(name):
- aliases = []
- addresses = []
- tuples = _getaddrinfo(name, 0, socket.AF_INET, socket.SOCK_STREAM,
- socket.SOL_TCP, socket.AI_CANONNAME)
- canonical = tuples[0][3]
- for item in tuples:
- addresses.append(item[4][0])
- # XXX we just ignore aliases
- return (canonical, aliases, addresses)
-
-def _gethostbyaddr(ip):
- try:
- addr = dns.ipv6.inet_aton(ip)
- sockaddr = (ip, 80, 0, 0)
- family = socket.AF_INET6
- except:
- sockaddr = (ip, 80)
- family = socket.AF_INET
- (name, port) = _getnameinfo(sockaddr, socket.NI_NAMEREQD)
- aliases = []
- addresses = []
- tuples = _getaddrinfo(name, 0, family, socket.SOCK_STREAM, socket.SOL_TCP,
- socket.AI_CANONNAME)
- canonical = tuples[0][3]
- for item in tuples:
- addresses.append(item[4][0])
- # XXX we just ignore aliases
- return (canonical, aliases, addresses)
-
-def override_system_resolver(resolver=None):
- """Override the system resolver routines in the socket module with
- versions which use dnspython's resolver.
-
- This can be useful in testing situations where you want to control
- the resolution behavior of python code without having to change
- the system's resolver settings (e.g. /etc/resolv.conf).
-
- The resolver to use may be specified; if it's not, the default
- resolver will be used.
-
- @param resolver: the resolver to use
- @type resolver: dns.resolver.Resolver object or None
- """
- if resolver is None:
- resolver = get_default_resolver()
- global _resolver
- _resolver = resolver
- socket.getaddrinfo = _getaddrinfo
- socket.getnameinfo = _getnameinfo
- socket.getfqdn = _getfqdn
- socket.gethostbyname = _gethostbyname
- socket.gethostbyname_ex = _gethostbyname_ex
- socket.gethostbyaddr = _gethostbyaddr
-
-def restore_system_resolver():
- """Undo the effects of override_system_resolver().
- """
- global _resolver
- _resolver = None
- socket.getaddrinfo = _original_getaddrinfo
- socket.getnameinfo = _original_getnameinfo
- socket.getfqdn = _original_getfqdn
- socket.gethostbyname = _original_gethostbyname
- socket.gethostbyname_ex = _original_gethostbyname_ex
- socket.gethostbyaddr = _original_gethostbyaddr
git.samba.org / bbaumbach / samba-autobuild / .git / blobdiff