twisted.names.server.DNSServerFactory(protocol.ServerFactory)
class documentationtwisted.names.server
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Server factory and tracker for DNSProtocol
connections. This class also provides records for responses to DNS
queries.
Instance Variable | cache | A Cache
instance whose cacheResult method is called when a response is
received from one of clients . Defaults to None
if no caches are specified. See caches of __init__
for more details. (type: Cache or
None ) |
Instance Variable | canRecurse | A flag indicating whether this server is capable of performing recursive
DNS resolution. (type: bool ) |
Instance Variable | resolver | A resolve.ResolverChain
containing an ordered list of authorities , caches
and clients to which queries will be dispatched. (type: resolve.ResolverChain ) |
Instance Variable | verbose | See __init__ |
Instance Variable | connections | A list of all the connected DNSProtocol
instances using this object as their controller. (type: list of DNSProtocol
instances) |
Instance Variable | protocol | A callable used for building a DNS stream protocol. Called by DNSServerFactory.buildProtocol
and passed the DNSServerFactory
instance as the one and only positional argument. Defaults to dns.DNSProtocol . (type: IProtocolFactory
constructor) |
Method | __init__ | |
Method | buildProtocol | Create an instance of a subclass of Protocol. |
Method | connectionMade | Track a newly connected DNSProtocol . |
Method | connectionLost | Stop tracking a no-longer connected DNSProtocol . |
Method | sendReply | Send a response message to a given address via
the supplied protocol . |
Method | gotResolverResponse | A callback used by DNSServerFactory.handleQuery
for handling the deferred response from
self.resolver.query . |
Method | gotResolverError | A callback used by DNSServerFactory.handleQuery
for handling deferred errors from self.resolver.query . |
Method | handleQuery | Called by DNSServerFactory.messageReceived
when a query message is received. |
Method | handleInverseQuery | Called by DNSServerFactory.messageReceived
when an inverse query message is received. |
Method | handleStatus | Called by DNSServerFactory.messageReceived
when a status message is received. |
Method | handleNotify | Called by DNSServerFactory.messageReceived
when a notify message is received. |
Method | handleOther | Called by DNSServerFactory.messageReceived
when a message with unrecognised OPCODE is received. |
Method | messageReceived | No summary |
Method | allowQuery | Called by DNSServerFactory.messageReceived
to decide whether to process a received message or to reply with
dns.EREFUSED . |
Instance Variable | _messageFactory | A response message constructor with an initializer signature matching dns.Message.__init__ . (type: callable ) |
Method | _verboseLog | Log a message only if verbose logging is enabled. |
Method | _responseFromMessage | Generate a Message instance
suitable for use as the response to message . |
Inherited from Factory (via ServerFactory):
Class Method | forProtocol | Create a factory for the given protocol. |
Method | logPrefix | Describe this factory for log messages. |
Method | doStart | Make sure startFactory is called. |
Method | doStop | Make sure stopFactory is called. |
Method | startFactory | This will be called before I begin listening on a Port or Connector. |
Method | stopFactory | This will be called before I stop listening on all Ports/Connectors. |
bool
)
resolve.ResolverChain
containing an ordered list of authorities
, caches
and clients
to which queries will be dispatched. (type: resolve.ResolverChain
)
DNSProtocol
instances using this object as their controller. (type: list
of DNSProtocol
instances)
DNSServerFactory.buildProtocol
and passed the DNSServerFactory
instance as the one and only positional argument. Defaults to dns.DNSProtocol
. (type: IProtocolFactory
constructor)
dns.Message.__init__
. (type: callable
)
Parameters | authorities | Resolvers which provide authoritative answers. (type: list
of IResolver
providers) |
caches | Resolvers which provide cached non-authoritative answers. The first cache
instance is assigned to DNSServerFactory.cache and its
cacheResult method will be called when a response is received
from one of clients . (type: list
of Cache
instances) | |
clients | Resolvers which are capable of performing recursive DNS lookups. (type: list
of IResolver
providers) | |
verbose | An integer controlling the verbosity of logging of queries and responses.
Default is 0 which means no logging. Set to 2 to
enable logging of full query and response messages. (type: int ) |
Log a message only if verbose logging is enabled.
Parameters | args | Positional arguments which will be passed to log.msg |
kwargs | Keyword arguments which will be passed to log.msg |
Create an instance of a subclass of Protocol.
The returned instance will handle input on an incoming server connection, and an attribute "factory" pointing to the creating factory.
Alternatively, None
may be returned to immediately close the new connection.
Override this method to alter how Protocol instances get created.
Parameters | addr | an object implementing twisted.internet.interfaces.IAddress |
Track a newly connected DNSProtocol
.
Parameters | protocol | The protocol instance to be tracked. (type: dns.DNSProtocol ) |
Stop tracking a no-longer connected DNSProtocol
.
Parameters | protocol | The tracked protocol instance to be which has been lost. (type: dns.DNSProtocol ) |
Send a response message
to a given address
via
the supplied protocol
.
Message payload will be logged if DNSServerFactory.verbose
is >1
.
Parameters | protocol | The DNS protocol instance to which to send the message. (type: dns.DNSDatagramProtocol
or dns.DNSProtocol ) |
message | The DNS message to be sent. (type: dns.Message ) | |
address | The address to which the message will be sent or None
if protocol is a stream protocol. (type: tuple
or None ) |
Generate a Message
instance
suitable for use as the response to message
.
queries
will be copied from the request to the
response.
rCode
, answers
, authority
and
additional
will be assigned to the response, if supplied.
The recAv
flag will be set on the response if the
canRecurse
flag on this DNSServerFactory
is set to True
.
The auth
flag will be set on the response if *any* of the
supplied answers
have their auth
flag set to True
.
The response will have the same maxSize
as the request.
Additionally, the response will have a timeReceived
attribute whose value is that of the original request and the
Parameters | message | The request message (type: int ) |
rCode | The response code which will be assigned to the response. | |
answers | An optional list of answer records which will be assigned to the response. (type: list
of dns.RRHeader ) | |
authority | An optional list of authority records which will be assigned to the
response. (type: list
of dns.RRHeader ) | |
additional | An optional list of additional records which will be assigned to the
response. (type: list
of dns.RRHeader ) | |
Returns | A response Message instance. (type: Message ) | |
See Also | dns._responseFromMessage |
A callback used by DNSServerFactory.handleQuery
for handling the deferred response from
self.resolver.query
.
Constructs a response message by combining the original query message with the resolved answer, authority and additional records.
Marks the response message as authoritative if any of the resolved answers are found to be authoritative.
The resolved answers count will be logged if
DNSServerFactory.verbose
is >1
.
Parameters | response | Answer records, authority records and additional records (type: tuple
of list
of dns.RRHeader
instances) |
protocol | The DNS protocol instance to which to send a response message. (type: dns.DNSDatagramProtocol
or dns.DNSProtocol ) | |
message | The original DNS query message for which a response message will be
constructed. (type: dns.Message ) | |
address | The address to which the response message will be sent or None
if protocol is a stream protocol. (type: tuple
or None ) |
A callback used by DNSServerFactory.handleQuery
for handling deferred errors from self.resolver.query
.
Constructs a response message from the original query message by
assigning a suitable error code to rCode
.
An error message will be logged if DNSServerFactory.verbose
is >1
.
Parameters | failure | The reason for the failed resolution (as reported by
self.resolver.query ). (type: Failure ) |
protocol | The DNS protocol instance to which to send a response message. (type: dns.DNSDatagramProtocol
or dns.DNSProtocol ) | |
message | The original DNS query message for which a response message will be
constructed. (type: dns.Message ) | |
address | The address to which the response message will be sent or None
if protocol is a stream protocol. (type: tuple
or None ) |
Called by DNSServerFactory.messageReceived
when a query message is received.
Takes the first query from the received message and dispatches it to
self.resolver.query
.
Adds callbacks DNSServerFactory.gotResolverResponse
and DNSServerFactory.gotResolverError
to the resulting deferred.
Note: Multiple queries in a single message are not supported because there is no standard way to respond with multiple rCodes, auth, etc. This is consistent with other DNS server implementations. See http://tools.ietf.org/html/draft-ietf-dnsext-edns1-03 for a proposed solution.
Parameters | protocol | The DNS protocol instance to which to send a response message. (type: dns.DNSDatagramProtocol
or dns.DNSProtocol ) |
message | The original DNS query message for which a response message will be
constructed. (type: dns.Message ) | |
address | The address to which the response message will be sent or None
if protocol is a stream protocol. (type: tuple
or None ) | |
Returns | A deferred which fires with the resolved result or error of
the first query in message . (type: Deferred ) |
Called by DNSServerFactory.messageReceived
when an inverse query message is received.
Replies with a Not Implemented error by default.
An error message will be logged if DNSServerFactory.verbose
is >1
.
Override in a subclass.
Parameters | protocol | The DNS protocol instance to which to send a response message. (type: dns.DNSDatagramProtocol
or dns.DNSProtocol ) |
message | The original DNS query message for which a response message will be
constructed. (type: dns.Message ) | |
address | The address to which the response message will be sent or None
if protocol is a stream protocol. (type: tuple
or None ) |
Called by DNSServerFactory.messageReceived
when a status message is received.
Replies with a Not Implemented error by default.
An error message will be logged if DNSServerFactory.verbose
is >1
.
Override in a subclass.
Parameters | protocol | The DNS protocol instance to which to send a response message. (type: dns.DNSDatagramProtocol
or dns.DNSProtocol ) |
message | The original DNS query message for which a response message will be
constructed. (type: dns.Message ) | |
address | The address to which the response message will be sent or None
if protocol is a stream protocol. (type: tuple
or None ) |
Called by DNSServerFactory.messageReceived
when a notify message is received.
Replies with a Not Implemented error by default.
An error message will be logged if DNSServerFactory.verbose
is >1
.
Override in a subclass.
Parameters | protocol | The DNS protocol instance to which to send a response message. (type: dns.DNSDatagramProtocol
or dns.DNSProtocol ) |
message | The original DNS query message for which a response message will be
constructed. (type: dns.Message ) | |
address | The address to which the response message will be sent or None
if protocol is a stream protocol. (type: tuple
or None ) |
Called by DNSServerFactory.messageReceived
when a message with unrecognised OPCODE is received.
Replies with a Not Implemented error by default.
An error message will be logged if DNSServerFactory.verbose
is >1
.
Override in a subclass.
Parameters | protocol | The DNS protocol instance to which to send a response message. (type: dns.DNSDatagramProtocol
or dns.DNSProtocol ) |
message | The original DNS query message for which a response message will be
constructed. (type: dns.Message ) | |
address | The address to which the response message will be sent or None
if protocol is a stream protocol. (type: tuple
or None ) |
DNSServerFactory.messageReceived
is called by protocols which are under the control of this DNSServerFactory
whenever they receive a DNS query message or an unexpected / duplicate /
late DNS response message.
DNSServerFactory.allowQuery
is called with the received message, protocol and origin address. If it
returns False
,
a dns.EREFUSED
response is sent back to the client.
Otherwise the received message is dispatched to one of DNSServerFactory.handleQuery
,
DNSServerFactory.handleInverseQuery
,
DNSServerFactory.handleStatus
,
DNSServerFactory.handleNotify
,
or DNSServerFactory.handleOther
depending on the OPCODE of the received message.
If DNSServerFactory.verbose
is >0
all
received messages will be logged in more or less detail depending on the
value of verbose
.
Parameters | message | The DNS message that was received. (type: dns.Message ) |
proto | The DNS protocol instance which received the message (type: dns.DNSDatagramProtocol
or dns.DNSProtocol ) | |
address | The address from which the message was received. Only provided for messages
received by datagram protocols. The origin of Messages received from stream
protocols can be gleaned from the protocol transport
attribute. (type: tuple
or None ) |
Called by DNSServerFactory.messageReceived
to decide whether to process a received message or to reply with
dns.EREFUSED
.
This default implementation permits anything but empty queries.
Override in a subclass to implement alternative policies.
Parameters | message | The DNS message that was received. (type: dns.Message ) |
protocol | The DNS protocol instance which received the message (type: dns.DNSDatagramProtocol
or dns.DNSProtocol ) | |
address | The address from which the message was received. Only provided for messages
received by datagram protocols. The origin of Messages received from stream
protocols can be gleaned from the protocol transport
attribute. (type: tuple
or None ) | |
Returns | True
if the received message contained one or more queries, else False . (type: bool ) |