Scriptable structures
=====================
module_qstate
-----------------------
.. class:: module_qstate
Module state, per query.
This class provides these data attributes:
.. attribute:: qinfo
(:class:`query_info`) Informations about query being answered. Name, RR type, RR class.
.. attribute:: query_flags
(uint16) Flags for query. See QF_BIT\_ predefined constants.
.. attribute:: is_priming
If this is a (stub or root) priming query (with hints).
.. attribute:: reply
comm_reply contains server replies.
.. attribute:: return_msg
(:class:`dns_msg`) The reply message, with message for client and calling module (read-only attribute).
Note that if you want to create of modify return_msg you should use :class:`DNSMessage`.
.. attribute:: return_rcode
The rcode, in case of error, instead of a reply message. Determines whether the return_msg contains reply.
.. attribute:: region
Region for this query. Cleared when query process finishes.
.. attribute:: curmod
Which module is executing.
.. attribute:: ext_state[]
Module states.
.. attribute:: env
Environment for this query.
.. attribute:: mesh_info
Mesh related information for this query.
query_info
----------------
.. class:: query_info
This class provides these data attributes:
.. attribute:: qname
The original question in the wireformat format (e.g. \\x03www\\x03nic\\x02cz\\x00 for www.nic.cz)
.. attribute:: qname_len
Lenght of question name (number of bytes).
.. attribute:: qname_list[]
The question ``qname`` converted into list of labels (e.g. ['www','nic','cz',''] for www.nic.cz)
.. attribute:: qname_str
The question ``qname`` converted into string (e.g. www.nic.cz. for www.nic.cz)
.. attribute:: qtype
The class type asked for. See RR_TYPE\_ predefined constants.
.. attribute:: qtype_str
The ``qtype`` in display presentation format (string) (e.g 'A' for RR_TYPE_A)
.. attribute:: qclass
The question class. See RR_CLASS\_ predefined constants.
.. attribute:: qclass_str
The ``qclass`` in display presentation format (string).
reply_info
--------------------
.. class:: reply_info
This class provides these data attributes:
.. attribute:: flags
The flags for the answer, host byte order.
.. attribute:: qdcount
Number of RRs in the query section.
If qdcount is not 0, then it is 1, and the data that appears
in the reply is the same as the query_info.
Host byte order.
.. attribute:: ttl
TTL of the entire reply (for negative caching).
only for use when there are 0 RRsets in this message.
if there are RRsets, check those instead.
.. attribute:: security
The security status from DNSSEC validation of this message. See sec_status\_ predefined constants.
.. attribute:: an_numrrsets
Number of RRsets in each section.
The answer section. Add up the RRs in every RRset to calculate
the number of RRs, and the count for the dns packet.
The number of RRs in RRsets can change due to RRset updates.
.. attribute:: ns_numrrsets
Count of authority section RRsets
.. attribute:: ar_numrrsets
Count of additional section RRsets
.. attribute:: rrset_count
Number of RRsets: an_numrrsets + ns_numrrsets + ar_numrrsets
.. attribute:: rrsets[]
(:class:`ub_packed_rrset_key`) List of RR sets in the order in which they appear in the reply message.
Number of elements is ancount + nscount + arcount RRsets.
.. attribute:: ref[]
(:class:`rrset_ref`) Packed array of ids (see counts) and pointers to packed_rrset_key.
The number equals ancount + nscount + arcount RRsets.
These are sorted in ascending pointer, the locking order. So
this list can be locked (and id, ttl checked), to see if
all the data is available and recent enough.
dns_msg
--------------
.. class:: dns_msg
Region allocated message reply
This class provides these data attributes:
.. attribute:: qinfo
(:class:`query_info`) Informations about query.
.. attribute:: rep
(:class:`reply_info`) This attribute points to the packed reply structure.
packed_rrset_key
----------------------
.. class:: packed_rrset_key
The identifying information for an RRset.
This class provides these data attributes:
.. attribute:: dname
The domain name. If not empty (for ``id = None``) it is allocated, and
contains the wireformat domain name. This dname is not canonicalized.
E.g., the dname contains \\x03www\\x03nic\\x02cz\\x00 for www.nic.cz.
.. attribute:: dname_len
Length of the domain name, including last 0 root octet.
.. attribute:: dname_list[]
The domain name ``dname`` converted into list of labels (see :attr:`query_info.qname_list`).
.. attribute:: dname_str
The domain name ``dname`` converted into string (see :attr:`query_info.qname_str`).
.. attribute:: flags
Flags.
.. attribute:: type
The rrset type in network format.
.. attribute:: type_str
The rrset type in display presentation format.
.. attribute:: rrset_class
The rrset class in network format.
.. attribute:: rrset_class_str
The rrset class in display presentation format.
ub_packed_rrset_key
-------------------------
.. class:: ub_packed_rrset_key
This structure contains an RRset. A set of resource records that
share the same domain name, type and class.
Due to memory management and threading, the key structure cannot be
deleted, although the data can be. The id can be set to 0 to store and the
structure can be recycled with a new id.
The :class:`ub_packed_rrset_key` provides these data attributes:
.. attribute:: entry
(:class:`lruhash_entry`) Entry into hashtable. Note the lock is never destroyed,
even when this key is retired to the cache.
the data pointer (if not None) points to a :class:`packed_rrset`.
.. attribute:: id
The ID of this rrset. unique, based on threadid + sequenceno.
ids are not reused, except after flushing the cache.
zero is an unused entry, and never a valid id.
Check this value after getting entry.lock.
The other values in this struct may only be altered after changing
the id (which needs a writelock on entry.lock).
.. attribute:: rk
(:class:`packed_rrset_key`) RR set data.
lruhash_entry
-------------------------
.. class:: lruhash_entry
The :class:`ub_packed_rrset_key` provides these data attributes:
.. attribute:: lock
rwlock for access to the contents of the entry. Note that you cannot change hash and key, if so, you have to delete it to change hash or key.
.. attribute:: data
(:class:`packed_rrset_data`) entry data stored in wireformat (RRs and RRsigs).
packed_rrset_data
-----------------------
.. class:: packed_rrset_data
Rdata is stored in wireformat. The dname is stored in wireformat.
TTLs are stored as absolute values (and could be expired).
RRSIGs are stored in the arrays after the regular rrs.
You need the packed_rrset_key to know dname, type, class of the
resource records in this RRset. (if signed the rrsig gives the type too).
The :class:`packed_rrset_data` provides these data attributes:
.. attribute:: ttl
TTL (in seconds like time()) of the RRset.
Same for all RRs see rfc2181(5.2).
.. attribute:: count
Number of RRs.
.. attribute:: rrsig_count
Number of rrsigs, if 0 no rrsigs.
.. attribute:: trust
The trustworthiness of the RRset data.
.. attribute:: security
Security status of the RRset data. See sec_status\_ predefined constants.
.. attribute:: rr_len[]
Length of every RR's rdata, rr_len[i] is size of rr_data[i].
.. attribute:: rr_ttl[]
TTL of every rr. rr_ttl[i] ttl of rr i.
.. attribute:: rr_data[]
Array of RR's rdata (list of strings). The rdata is stored in uncompressed wireformat.
The first 16B of rr_data[i] is rdlength in network format.
DNSMessage
----------------
.. class:: DNSMessage
Abstract representation of DNS message.
**Usage**
This example shows how to create an authoritative answer response
::
msg = DNSMessage(qstate.qinfo.qname_str, RR_TYPE_A, RR_CLASS_IN, PKT_AA)
#append RR
if (qstate.qinfo.qtype == RR_TYPE_A) or (qstate.qinfo.qtype == RR_TYPE_ANY):
msg.answer.append("%s 10 IN A 127.0.0.1" % qstate.qinfo.qname_str)
#set qstate.return_msg
if not msg.set_return_msg(qstate):
raise Exception("Can't create response")
The :class:`DNSMessage` provides these methods and data attributes:
.. method:: __init__(self, rr_name, rr_type, rr_class = RR_CLASS_IN, query_flags = 0, default_ttl = 0)
Prepares an answer (DNS packet) from qiven information. Query flags are combination of PKT_xx contants.
.. method:: set_return_msg(self, qstate)
This method fills qstate return message according to the given informations.
It takes lists of RRs in each section of answer, created necessray RRsets in wire format and store the result in :attr:`qstate.return_msg`.
Returns 1 if OK.
.. attribute:: rr_name
RR name of question.
.. attribute:: rr_type
RR type of question.
.. attribute:: rr_class
RR class of question.
.. attribute:: default_ttl
Default time-to-live.
.. attribute:: query_flags
Query flags. See PKT\_ predefined constants.
.. attribute:: question[]
List of resource records that should appear (in the same order) in question section of answer.
.. attribute:: answer[]
List of resource records that should appear (in the same order) in answer section of answer.
.. attribute:: authority[]
List of resource records that should appear (in the same order) in authority section of answer.
.. attribute:: additional[]
List of resource records that should appear (in the same order) in additional section of answer.
pythonmod_env
-----------------------
.. class:: pythonmod_env
Global state for the module.
This class provides these data attributes:
.. attribute:: data
Here you can keep your own data shared across each thread.
.. attribute:: fname
Python script filename.
.. attribute:: qstate
Module query state.
pythonmod_qstate
-----------------------
.. class:: pythonmod_qstate
Per query state for the iterator module.
This class provides these data attributes:
.. attribute:: data
Here you can keep your own private data (each thread has own data object).