twisted.names.dns._EDNSMessage

class documentation

class _EDNSMessage(tputil.FancyEqMixin): (source)

Constructor: _EDNSMessage(id, answer, opCode, auth, ...)

View In Hierarchy

An EDNS message.

Designed for compatibility with Message but with a narrower public interface.

Most importantly, _EDNSMessage.fromStr will interpret and remove OPT records that are present in the additional records section.

The OPT records are used to populate certain EDNS specific attributes.

_EDNSMessage.toStr will add suitable OPT records to the additional section to represent the extended EDNS information.

See Also
https://tools.ietf.org/html/rfc6891
Method __init__ Construct a new _EDNSMessage
Method __repr__ Undocumented
Method fromStr Decode from wire format, saving flags, values and records to this _EDNSMessage instance in place.
Method toStr Encode to wire format by first converting to a standard dns.Message.
Class Variable compareAttributes Undocumented
Instance Variable additional See __init__
Instance Variable answer See __init__
Instance Variable answers See __init__
Instance Variable auth See __init__
Instance Variable authenticData See __init__
Instance Variable authority See __init__
Instance Variable checkingDisabled See __init__
Instance Variable dnssecOK See __init__
Instance Variable ednsVersion See __init__
Instance Variable id See __init__
Instance Variable maxSize See __init__
Instance Variable opCode See __init__
Instance Variable queries See __init__
Instance Variable rCode See __init__
Instance Variable recAv See __init__
Instance Variable recDes See __init__
Instance Variable trunc See __init__
Class Method _fromMessage Construct and return a new _EDNSMessage whose attributes and records are derived from the attributes and records of message (a Message instance).
Method _toMessage Convert to a standard dns.Message.
Instance Variable _messageFactory A constructor of Message instances. Called by _toMessage and _fromMessage.

Inherited from FancyEqMixin:

Method __eq__ Undocumented
Method __ne__ Undocumented
def __init__(self, id=0, answer=False, opCode=OP_QUERY, auth=False, trunc=False, recDes=False, recAv=False, rCode=0, ednsVersion=0, dnssecOK=False, authenticData=False, checkingDisabled=False, maxSize=512, queries=None, answers=None, authority=None, additional=None): (source)

Construct a new _EDNSMessage

Parameters
id:intA 16 bit identifier assigned by the program that generates any kind of query. This identifier is copied the corresponding reply and can be used by the requester to match up replies to outstanding queries.
answer:boolA one bit field that specifies whether this message is a query (0), or a response (1).
opCode:intA four bit field that specifies kind of query in this message. This value is set by the originator of a query and copied into the response.
auth:boolAuthoritative Answer - this bit is valid in responses, and specifies that the responding name server is an authority for the domain name in question section.
trunc:boolTruncation - specifies that this message was truncated due to length greater than that permitted on the transmission channel.
recDes:boolRecursion Desired - this bit may be set in a query and is copied into the response. If set, it directs the name server to pursue the query recursively. Recursive query support is optional.
recAv:boolRecursion Available - this bit is set or cleared in a response, and denotes whether recursive query support is available in the name server.
rCode:intExtended 12-bit RCODE. Derived from the 4 bits defined in RFC1035 4.1.1 and the upper 8bits defined in RFC6891 6.1.3.
ednsVersion:int or NoneIndicates the EDNS implementation level. Set to None to prevent any EDNS attributes and options being added to the encoded byte string.
dnssecOK:boolDNSSEC OK bit as defined by RFC3225 3.
authenticData:boolA flag indicating in a response that all the data included in the answer and authority portion of the response has been authenticated by the server according to the policies of that server. See RFC2535 section-6.1.
checkingDisabledA flag indicating in a query that pending (non-authenticated) data is acceptable to the resolver sending the query. See RFC2535 section-6.1.
maxSize:intThe requestor's UDP payload size is the number of octets of the largest UDP payload that can be reassembled and delivered in the requestor's network stack.
queries:list of QueryThe list of Query associated with this message.
answers:list of RRHeaderThe list of answers associated with this message.
authority:list of RRHeaderThe list of authority records associated with this message.
additional:list of RRHeaderThe list of additional records associated with this message.
See Also
RFC1035 section-4.1.1
RFC2535 section-6.1
RFC3225 section-3
RFC6891 section-6.1.3
def __repr__(self) -> str: (source)

Undocumented

def fromStr(self, bytes): (source)

Decode from wire format, saving flags, values and records to this _EDNSMessage instance in place.

Parameters
bytes:bytesThe full byte string to be decoded.
def toStr(self): (source)

Encode to wire format by first converting to a standard dns.Message.

Returns
A bytes string.
compareAttributes: tuple[str, ...] = (source)
overrides twisted.python.util.FancyEqMixin.compareAttributes

Undocumented

additional = (source)
answer = (source)
answers = (source)
auth = (source)
authenticData = (source)
authority = (source)
checkingDisabled = (source)
dnssecOK = (source)
ednsVersion = (source)
id = (source)
maxSize = (source)
opCode = (source)
queries = (source)
rCode = (source)
recAv = (source)
recDes = (source)
trunc = (source)
@classmethod
def _fromMessage(cls, message): (source)

Construct and return a new _EDNSMessage whose attributes and records are derived from the attributes and records of message (a Message instance).

If present, an OPT record will be extracted from the additional section and its attributes and options will be used to set the EDNS specific attributes extendedRCODE, ednsVersion, dnssecOK, ednsOptions.

The extendedRCODE will be combined with message.rCode and assigned to self.rCode.

Parameters
message:MessageThe source Message.
Returns
_EDNSMessageA new _EDNSMessage
def _toMessage(self): (source)

Convert to a standard dns.Message.

If ednsVersion is not None, an _OPTHeader instance containing all the EDNS specific attributes and options will be appended to the list of additional records.

Returns
dns.MessageA dns.Message
_messageFactory = (source)

A constructor of Message instances. Called by _toMessage and _fromMessage.