twisted.names.client.Resolver(common.ResolverBase) class documentation

Part of twisted.names.client View Source (View In Hierarchy)
Method __init__ No summary
Method __getstate__ Undocumented
Method __setstate__ Undocumented
Method maybeParseConfig Undocumented
Method parseConfig Undocumented
Method pickServer Return the address of a nameserver.
Method connectionMade Called by associated dns.DNSProtocol instances when they connect.
Method connectionLost Called by associated dns.DNSProtocol instances when they disconnect.
Method messageReceived Undocumented
Method queryUDP Make a number of DNS queries via UDP.
Method queryTCP Make a number of DNS queries via TCP.
Method filterAnswers Extract results from the given message.
Method lookupZone Perform an AXFR record lookup.
Instance Variable _waiting A dict mapping tuple keys of query name/type/class to Deferreds which will be called back with the result of those queries. This is used to avoid issuing the same query more than once in parallel. This is more efficient on the network and helps avoid a "birthday paradox" attack by keeping the number of outstanding requests for a particular query fixed at one instead of allowing the attacker to raise it to an arbitrary number.
Instance Variable _reactor A provider of IReactorTCP, IReactorUDP, and IReactorTime which will be used to set up network resources and track timeouts.
Method _openFile Wrapper used for opening files in the class, exists primarily for unit testing purposes.
Method _connectedProtocol Return a new DNSDatagramProtocol bound to a randomly selected port number.
Method _query Get a new DNSDatagramProtocol instance from _connectedProtocol, issue a query to it using *args, and arrange for it to be disconnected from its transport after the query completes.
Method _reissue Undocumented
Method _lookup Build a dns.Query for the given parameters and dispatch it via UDP.
Method _timeoutZone Undocumented
Method _cbLookupZone Undocumented

Inherited from ResolverBase:

Method exceptionForCode Convert a response code (one of the possible values of dns.Message.rCode to an exception instance representing it.
Method query Dispatch query to the method which can handle its type.
Method lookupAddress Perform an A record lookup.
Method lookupIPV6Address Perform an AAAA record lookup.
Method lookupAddress6 Perform an A6 record lookup.
Method lookupMailExchange Perform an MX record lookup.
Method lookupNameservers Perform an NS record lookup.
Method lookupCanonicalName Perform a CNAME record lookup.
Method lookupMailBox Perform an MB record lookup.
Method lookupMailGroup Perform an MG record lookup.
Method lookupMailRename Perform an MR record lookup.
Method lookupPointer Perform a PTR record lookup.
Method lookupAuthority Perform an SOA record lookup.
Method lookupNull Perform a NULL record lookup.
Method lookupWellKnownServices Perform a WKS record lookup.
Method lookupService Perform an SRV record lookup.
Method lookupHostInfo Perform a HINFO record lookup.
Method lookupMailboxInfo Perform an MINFO record lookup.
Method lookupText Perform a TXT record lookup.
Method lookupSenderPolicy Perform a SPF record lookup.
Method lookupResponsibility Perform an RP record lookup.
Method lookupAFSDatabase Perform an AFSDB record lookup.
Method lookupNamingAuthorityPointer Perform a NAPTR record lookup.
Method lookupAllRecords Perform an ALL_RECORD lookup.
Method getHostByName Resolve the domain name name into an IP address.
Class Variable _errormap A dict mapping DNS protocol failure response codes to exception classes which will be used to represent those failures.
Method _cbRecords Undocumented
_waiting =
A dict mapping tuple keys of query name/type/class to Deferreds which will be called back with the result of those queries. This is used to avoid issuing the same query more than once in parallel. This is more efficient on the network and helps avoid a "birthday paradox" attack by keeping the number of outstanding requests for a particular query fixed at one instead of allowing the attacker to raise it to an arbitrary number.
_reactor =
A provider of IReactorTCP, IReactorUDP, and IReactorTime which will be used to set up network resources and track timeouts.
def __init__(self, resolv=None, servers=None, timeout=(1, 3, 11, 45), reactor=None): (source)
overrides twisted.names.common.ResolverBase.__init__

Construct a resolver which will query domain name servers listed in the resolv.conf(5)-format file given by resolv as well as those in the given servers list. Servers are queried in a round-robin fashion. If given, resolv is periodically checked for modification and re-parsed if it is noticed to have changed.

ParametersserversIf not None, interpreted as a list of (host, port) pairs specifying addresses of domain name servers to attempt to use for this lookup. Host addresses should be in IPv4 dotted-quad form. If specified, overrides resolv. (type: list of (str, int) or None)
resolvFilename to read and parse as a resolver(5) configuration file. (type: str)
timeoutDefault number of seconds after which to reissue the query. When the last timeout expires, the query is considered failed. (type: Sequence of int)
reactorA provider of IReactorTime, IReactorUDP, and IReactorTCP which will be used to establish connections, listen for DNS datagrams, and enforce timeouts. If not provided, the global reactor will be used.
RaisesValueErrorRaised if no nameserver addresses can be found.
def __getstate__(self): (source)
Undocumented
def __setstate__(self, state): (source)
Undocumented
def _openFile(self, path): (source)

Wrapper used for opening files in the class, exists primarily for unit testing purposes.

def maybeParseConfig(self): (source)
Undocumented
def parseConfig(self, resolvConf): (source)
Undocumented
def pickServer(self): (source)

Return the address of a nameserver.

TODO: Weight servers for response time so faster ones can be preferred.

def _connectedProtocol(self, interface=''): (source)

Return a new DNSDatagramProtocol bound to a randomly selected port number.

def connectionMade(self, protocol): (source)

Called by associated dns.DNSProtocol instances when they connect.

def connectionLost(self, protocol): (source)

Called by associated dns.DNSProtocol instances when they disconnect.

def messageReceived(self, message, protocol, address=None): (source)
Undocumented
def _query(self, *args): (source)

Get a new DNSDatagramProtocol instance from _connectedProtocol, issue a query to it using *args, and arrange for it to be disconnected from its transport after the query completes.

Parameters*argsPositional arguments to be passed to DNSDatagramProtocol.query.
ReturnsA Deferred which will be called back with the result of the query.
def queryUDP(self, queries, timeout=None): (source)

Make a number of DNS queries via UDP.

ParametersqueriesThe queries to make. (type: A list of dns.Query instances)
timeoutNumber of seconds after which to reissue the query. When the last timeout expires, the query is considered failed. (type: Sequence of int)
Returns (type: Deferred @raise twisted.internet.defer.TimeoutError: When the query times out.)
def _reissue(self, reason, addressesLeft, addressesUsed, query, timeout): (source)
Undocumented
def queryTCP(self, queries, timeout=10): (source)

Make a number of DNS queries via TCP.

ParametersqueriesThe queries to make. (type: Any non-zero number of dns.Query instances)
timeoutThe number of seconds after which to fail. (type: int)
Returns (type: Deferred)
def filterAnswers(self, message): (source)

Extract results from the given message.

If the message was truncated, re-attempt the query over TCP and return a Deferred which will fire with the results of that query.

If the message's result code is not twisted.names.dns.OK, return a Failure indicating the type of error which occurred.

Otherwise, return a three-tuple of lists containing the results from the answers section, the authority section, and the additional section.

def _lookup(self, name, cls, type, timeout): (source)
overrides twisted.names.common.ResolverBase._lookup

Build a dns.Query for the given parameters and dispatch it via UDP.

If this query is already outstanding, it will not be re-issued. Instead, when the outstanding query receives a response, that response will be re-used for this query as well.

ReturnsA Deferred which fires with a three-tuple giving the answer, authority, and additional sections of the response or with a Failure if the response code is anything other than dns.OK.
def lookupZone(self, name, timeout=10): (source)
from twisted.internet.interfaces.IResolver
overrides twisted.names.common.ResolverBase.lookupZone

Perform an AXFR record lookup.

NB This is quite different from other DNS requests. See http://cr.yp.to/djbdns/axfr-notes.html for more information.

NB Unlike other lookup* methods, the timeout here is not a list of ints, it is a single int.

ParametersnameDNS name to resolve. (type: str)
timeoutWhen this timeout expires, the query is considered failed. (type: int)
ReturnsA Deferred which fires with a three-tuple of lists of twisted.names.dns.RRHeader instances. The first element of the tuple gives answers. The second and third elements are always empty. The Deferred may instead fail with one of the exceptions defined in twisted.names.error or with NotImplementedError. (type: Deferred)
def _timeoutZone(self, d, controller, connector, seconds): (source)
Undocumented
def _cbLookupZone(self, result, connector): (source)
Undocumented
API Documentation for Twisted, generated by pydoctor at 2018-07-14 04:53:34.