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