2 * Copyright (C) 2004, 2005, 2007 Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (C) 1999-2003 Internet Software Consortium.
5 * Permission to use, copy, modify, and/or distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11 * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15 * PERFORMANCE OF THIS SOFTWARE.
18 /* $Id: db.h,v 1.76.18.10 2007/08/28 07:20:05 tbox Exp $ */
29 * The DNS DB interface allows named rdatasets to be stored and retrieved.
31 * The dns_db_t type is like a "virtual class". To actually use
32 * DBs, an implementation of the class is required.
37 * \li The module ensures appropriate synchronization of data structures it
38 * creates and manipulates.
41 * \li No anticipated impact.
47 * \li No anticipated impact.
58 #include <isc/magic.h>
59 #include <isc/ondestroy.h>
60 #include <isc/stdtime.h>
63 #include <dns/types.h>
71 typedef struct dns_dbmethods {
72 void (*attach)(dns_db_t *source, dns_db_t **targetp);
73 void (*detach)(dns_db_t **dbp);
74 isc_result_t (*beginload)(dns_db_t *db, dns_addrdatasetfunc_t *addp,
75 dns_dbload_t **dbloadp);
76 isc_result_t (*endload)(dns_db_t *db, dns_dbload_t **dbloadp);
77 isc_result_t (*dump)(dns_db_t *db, dns_dbversion_t *version,
79 dns_masterformat_t masterformat);
80 void (*currentversion)(dns_db_t *db,
81 dns_dbversion_t **versionp);
82 isc_result_t (*newversion)(dns_db_t *db,
83 dns_dbversion_t **versionp);
84 void (*attachversion)(dns_db_t *db, dns_dbversion_t *source,
85 dns_dbversion_t **targetp);
86 void (*closeversion)(dns_db_t *db,
87 dns_dbversion_t **versionp,
88 isc_boolean_t commit);
89 isc_result_t (*findnode)(dns_db_t *db, dns_name_t *name,
91 dns_dbnode_t **nodep);
92 isc_result_t (*find)(dns_db_t *db, dns_name_t *name,
93 dns_dbversion_t *version,
94 dns_rdatatype_t type, unsigned int options,
96 dns_dbnode_t **nodep, dns_name_t *foundname,
97 dns_rdataset_t *rdataset,
98 dns_rdataset_t *sigrdataset);
99 isc_result_t (*findzonecut)(dns_db_t *db, dns_name_t *name,
100 unsigned int options, isc_stdtime_t now,
101 dns_dbnode_t **nodep,
102 dns_name_t *foundname,
103 dns_rdataset_t *rdataset,
104 dns_rdataset_t *sigrdataset);
105 void (*attachnode)(dns_db_t *db,
106 dns_dbnode_t *source,
107 dns_dbnode_t **targetp);
108 void (*detachnode)(dns_db_t *db,
109 dns_dbnode_t **targetp);
110 isc_result_t (*expirenode)(dns_db_t *db, dns_dbnode_t *node,
112 void (*printnode)(dns_db_t *db, dns_dbnode_t *node,
114 isc_result_t (*createiterator)(dns_db_t *db,
115 isc_boolean_t relative_names,
116 dns_dbiterator_t **iteratorp);
117 isc_result_t (*findrdataset)(dns_db_t *db, dns_dbnode_t *node,
118 dns_dbversion_t *version,
119 dns_rdatatype_t type,
120 dns_rdatatype_t covers,
122 dns_rdataset_t *rdataset,
123 dns_rdataset_t *sigrdataset);
124 isc_result_t (*allrdatasets)(dns_db_t *db, dns_dbnode_t *node,
125 dns_dbversion_t *version,
127 dns_rdatasetiter_t **iteratorp);
128 isc_result_t (*addrdataset)(dns_db_t *db, dns_dbnode_t *node,
129 dns_dbversion_t *version,
131 dns_rdataset_t *rdataset,
132 unsigned int options,
133 dns_rdataset_t *addedrdataset);
134 isc_result_t (*subtractrdataset)(dns_db_t *db, dns_dbnode_t *node,
135 dns_dbversion_t *version,
136 dns_rdataset_t *rdataset,
137 unsigned int options,
138 dns_rdataset_t *newrdataset);
139 isc_result_t (*deleterdataset)(dns_db_t *db, dns_dbnode_t *node,
140 dns_dbversion_t *version,
141 dns_rdatatype_t type,
142 dns_rdatatype_t covers);
143 isc_boolean_t (*issecure)(dns_db_t *db);
144 unsigned int (*nodecount)(dns_db_t *db);
145 isc_boolean_t (*ispersistent)(dns_db_t *db);
146 void (*overmem)(dns_db_t *db, isc_boolean_t overmem);
147 void (*settask)(dns_db_t *db, isc_task_t *);
148 isc_result_t (*getoriginnode)(dns_db_t *db, dns_dbnode_t **nodep);
152 (*dns_dbcreatefunc_t)(isc_mem_t *mctx, dns_name_t *name,
153 dns_dbtype_t type, dns_rdataclass_t rdclass,
154 unsigned int argc, char *argv[], void *driverarg,
157 #define DNS_DB_MAGIC ISC_MAGIC('D','N','S','D')
158 #define DNS_DB_VALID(db) ISC_MAGIC_VALID(db, DNS_DB_MAGIC)
161 * This structure is actually just the common prefix of a DNS db
162 * implementation's version of a dns_db_t.
164 * Direct use of this structure by clients is forbidden. DB implementations
165 * may change the structure. 'magic' must be DNS_DB_MAGIC for any of the
166 * dns_db_ routines to work. DB implementations must maintain all DB
171 unsigned int impmagic;
172 dns_dbmethods_t * methods;
173 isc_uint16_t attributes;
174 dns_rdataclass_t rdclass;
176 isc_ondestroy_t ondest;
180 #define DNS_DBATTR_CACHE 0x01
181 #define DNS_DBATTR_STUB 0x02
185 * Options that can be specified for dns_db_find().
187 #define DNS_DBFIND_GLUEOK 0x01
188 #define DNS_DBFIND_VALIDATEGLUE 0x02
189 #define DNS_DBFIND_NOWILD 0x04
190 #define DNS_DBFIND_PENDINGOK 0x08
191 #define DNS_DBFIND_NOEXACT 0x10
192 #define DNS_DBFIND_FORCENSEC 0x20
193 #define DNS_DBFIND_COVERINGNSEC 0x40
198 * Options that can be specified for dns_db_addrdataset().
200 #define DNS_DBADD_MERGE 0x01
201 #define DNS_DBADD_FORCE 0x02
202 #define DNS_DBADD_EXACT 0x04
203 #define DNS_DBADD_EXACTTTL 0x08
207 * Options that can be specified for dns_db_subtractrdataset().
209 #define DNS_DBSUB_EXACT 0x01
220 dns_db_create(isc_mem_t *mctx, const char *db_type, dns_name_t *origin,
221 dns_dbtype_t type, dns_rdataclass_t rdclass,
222 unsigned int argc, char *argv[], dns_db_t **dbp);
224 * Create a new database using implementation 'db_type'.
227 * \li All names in the database must be subdomains of 'origin' and in class
228 * 'rdclass'. The database makes its own copy of the origin, so the
229 * caller may do whatever they like with 'origin' and its storage once the
232 * \li DB implementation-specific parameters are passed using argc and argv.
236 * \li dbp != NULL and *dbp == NULL
238 * \li 'origin' is a valid absolute domain name.
240 * \li mctx is a valid memory context
244 * \li A copy of 'origin' has been made for the databases use, and the
245 * caller is free to do whatever they want with the name and storage
246 * associated with 'origin'.
251 * \li #ISC_R_NOMEMORY
252 * \li #ISC_R_NOTFOUND db_type not found
254 * \li Many other errors are possible, depending on what db_type was
259 dns_db_attach(dns_db_t *source, dns_db_t **targetp);
261 * Attach *targetp to source.
265 * \li 'source' is a valid database.
267 * \li 'targetp' points to a NULL dns_db_t *.
271 * \li *targetp is attached to source.
275 dns_db_detach(dns_db_t **dbp);
277 * Detach *dbp from its database.
281 * \li 'dbp' points to a valid database.
287 * \li If '*dbp' is the last reference to the database,
288 * all resources used by the database will be freed
292 dns_db_ondestroy(dns_db_t *db, isc_task_t *task, isc_event_t **eventp);
294 * Causes 'eventp' to be sent to be sent to 'task' when the database is
297 * Note; ownership of the eventp is taken from the caller (and *eventp is
298 * set to NULL). The sender field of the event is set to 'db' before it is
303 dns_db_iscache(dns_db_t *db);
305 * Does 'db' have cache semantics?
309 * \li 'db' is a valid database.
312 * \li #ISC_TRUE 'db' has cache semantics
313 * \li #ISC_FALSE otherwise
317 dns_db_iszone(dns_db_t *db);
319 * Does 'db' have zone semantics?
323 * \li 'db' is a valid database.
326 * \li #ISC_TRUE 'db' has zone semantics
327 * \li #ISC_FALSE otherwise
331 dns_db_isstub(dns_db_t *db);
333 * Does 'db' have stub semantics?
337 * \li 'db' is a valid database.
340 * \li #ISC_TRUE 'db' has zone semantics
341 * \li #ISC_FALSE otherwise
345 dns_db_issecure(dns_db_t *db);
351 * \li 'db' is a valid database with zone semantics.
354 * \li #ISC_TRUE 'db' is secure.
355 * \li #ISC_FALSE 'db' is not secure.
359 dns_db_origin(dns_db_t *db);
361 * The origin of the database.
363 * Note: caller must not try to change this name.
367 * \li 'db' is a valid database.
371 * \li The origin of the database.
375 dns_db_class(dns_db_t *db);
377 * The class of the database.
381 * \li 'db' is a valid database.
385 * \li The class of the database.
389 dns_db_beginload(dns_db_t *db, dns_addrdatasetfunc_t *addp,
390 dns_dbload_t **dbloadp);
392 * Begin loading 'db'.
396 * \li 'db' is a valid database.
398 * \li This is the first attempt to load 'db'.
400 * \li addp != NULL && *addp == NULL
402 * \li dbloadp != NULL && *dbloadp == NULL
406 * \li On success, *addp will be a valid dns_addrdatasetfunc_t suitable
407 * for loading 'db'. *dbloadp will be a valid DB load context which
408 * should be used as 'arg' when *addp is called.
413 * \li #ISC_R_NOMEMORY
415 * \li Other results are possible, depending upon the database
416 * implementation used, syntax errors in the master file, etc.
420 dns_db_endload(dns_db_t *db, dns_dbload_t **dbloadp);
422 * Finish loading 'db'.
426 * \li 'db' is a valid database that is being loaded.
428 * \li dbloadp != NULL and *dbloadp is a valid database load context.
432 * \li *dbloadp == NULL
437 * \li #ISC_R_NOMEMORY
439 * \li Other results are possible, depending upon the database
440 * implementation used, syntax errors in the master file, etc.
444 dns_db_load(dns_db_t *db, const char *filename);
447 dns_db_load2(dns_db_t *db, const char *filename, dns_masterformat_t format);
449 * Load master file 'filename' into 'db'.
452 * \li This routine is equivalent to calling
455 * dns_db_beginload();
456 * dns_master_loadfile();
462 * \li 'db' is a valid database.
464 * \li This is the first attempt to load 'db'.
469 * \li #ISC_R_NOMEMORY
471 * \li Other results are possible, depending upon the database
472 * implementation used, syntax errors in the master file, etc.
476 dns_db_dump(dns_db_t *db, dns_dbversion_t *version, const char *filename);
479 dns_db_dump2(dns_db_t *db, dns_dbversion_t *version, const char *filename,
480 dns_masterformat_t masterformat);
482 * Dump version 'version' of 'db' to master file 'filename'.
486 * \li 'db' is a valid database.
488 * \li 'version' is a valid version.
493 * \li #ISC_R_NOMEMORY
495 * \li Other results are possible, depending upon the database
496 * implementation used, OS file errors, etc.
504 dns_db_currentversion(dns_db_t *db, dns_dbversion_t **versionp);
506 * Open the current version for reading.
510 * \li 'db' is a valid database with zone semantics.
512 * \li versionp != NULL && *verisonp == NULL
516 * \li On success, '*versionp' is attached to the current version.
521 dns_db_newversion(dns_db_t *db, dns_dbversion_t **versionp);
523 * Open a new version for reading and writing.
527 * \li 'db' is a valid database with zone semantics.
529 * \li versionp != NULL && *verisonp == NULL
533 * \li On success, '*versionp' is attached to the current version.
538 * \li #ISC_R_NOMEMORY
540 * \li Other results are possible, depending upon the database
541 * implementation used.
545 dns_db_attachversion(dns_db_t *db, dns_dbversion_t *source,
546 dns_dbversion_t **targetp);
548 * Attach '*targetp' to 'source'.
552 * \li 'db' is a valid database with zone semantics.
554 * \li source is a valid open version
556 * \li targetp != NULL && *targetp == NULL
560 * \li '*targetp' is attached to source.
564 dns_db_closeversion(dns_db_t *db, dns_dbversion_t **versionp,
565 isc_boolean_t commit);
567 * Close version '*versionp'.
569 * Note: if '*versionp' is a read-write version and 'commit' is ISC_TRUE,
570 * then all changes made in the version will take effect, otherwise they
571 * will be rolled back. The value if 'commit' is ignored for read-only
576 * \li 'db' is a valid database with zone semantics.
578 * \li '*versionp' refers to a valid version.
580 * \li If committing a writable version, then there must be no other
581 * outstanding references to the version (e.g. an active rdataset
586 * \li *versionp == NULL
588 * \li If *versionp is a read-write version, and commit is ISC_TRUE, then
589 * the version will become the current version. If !commit, then all
590 * changes made in the version will be undone, and the version will
591 * not become the current version.
599 dns_db_findnode(dns_db_t *db, dns_name_t *name, isc_boolean_t create,
600 dns_dbnode_t **nodep);
602 * Find the node with name 'name'.
605 * \li If 'create' is ISC_TRUE and no node with name 'name' exists, then
606 * such a node will be created.
608 * \li This routine is for finding or creating a node with the specified
609 * name. There are no partial matches. It is not suitable for use
610 * in building responses to ordinary DNS queries; clients which wish
611 * to do that should use dns_db_find() instead.
615 * \li 'db' is a valid database.
617 * \li 'name' is a valid, non-empty, absolute name.
619 * \li nodep != NULL && *nodep == NULL
623 * \li On success, *nodep is attached to the node with name 'name'.
628 * \li #ISC_R_NOTFOUND If !create and name not found.
629 * \li #ISC_R_NOMEMORY Can only happen if create is ISC_TRUE.
631 * \li Other results are possible, depending upon the database
632 * implementation used.
636 dns_db_find(dns_db_t *db, dns_name_t *name, dns_dbversion_t *version,
637 dns_rdatatype_t type, unsigned int options, isc_stdtime_t now,
638 dns_dbnode_t **nodep, dns_name_t *foundname,
639 dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset);
641 * Find the best match for 'name' and 'type' in version 'version' of 'db'.
645 * \li If type == dns_rdataset_any, then rdataset will not be bound.
647 * \li If 'options' does not have #DNS_DBFIND_GLUEOK set, then no glue will
648 * be returned. For zone databases, glue is as defined in RFC2181.
649 * For cache databases, glue is any rdataset with a trust of
652 * \li If 'options' does not have #DNS_DBFIND_PENDINGOK set, then no
653 * pending data will be returned. This option is only meaningful for
656 * \li If the #DNS_DBFIND_NOWILD option is set, then wildcard matching will
657 * be disabled. This option is only meaningful for zone databases.
659 * \li If the #DNS_DBFIND_FORCENSEC option is set, the database is assumed to
660 * have NSEC records, and these will be returned when appropriate. This
661 * is only necessary when querying a database that was not secure
664 * \li If the DNS_DBFIND_COVERINGNSEC option is set, then look for a
665 * NSEC record that potentially covers 'name' if a answer cannot
666 * be found. Note the returned NSEC needs to be checked to ensure
667 * that it is correct. This only affects answers returned from the
670 * \li To respond to a query for SIG records, the caller should create a
671 * rdataset iterator and extract the signatures from each rdataset.
673 * \li Making queries of type ANY with #DNS_DBFIND_GLUEOK is not recommended,
674 * because the burden of determining whether a given rdataset is valid
675 * glue or not falls upon the caller.
677 * \li The 'now' field is ignored if 'db' is a zone database. If 'db' is a
678 * cache database, an rdataset will not be found unless it expires after
679 * 'now'. Any ANY query will not match unless at least one rdataset at
680 * the node expires after 'now'. If 'now' is zero, then the current time
685 * \li 'db' is a valid database.
687 * \li 'type' is not SIG, or a meta-RR type other than 'ANY' (e.g. 'OPT').
689 * \li 'nodep' is NULL, or nodep is a valid pointer and *nodep == NULL.
691 * \li 'foundname' is a valid name with a dedicated buffer.
693 * \li 'rdataset' is NULL, or is a valid unassociated rdataset.
696 * on a non-error completion:
698 * \li If nodep != NULL, then it is bound to the found node.
700 * \li If foundname != NULL, then it contains the full name of the
703 * \li If rdataset != NULL and type != dns_rdatatype_any, then
704 * rdataset is bound to the found rdataset.
706 * Non-error results are:
708 * \li #ISC_R_SUCCESS The desired node and type were
711 * \li #DNS_R_WILDCARD The desired node and type were
712 * found after performing
713 * wildcard matching. This is
714 * only returned if the
715 * #DNS_DBFIND_INDICATEWILD
716 * option is set; otherwise
717 * #ISC_R_SUCCESS is returned.
719 * \li #DNS_R_GLUE The desired node and type were
720 * found, but are glue. This
721 * result can only occur if
722 * the DNS_DBFIND_GLUEOK option
723 * is set. This result can only
724 * occur if 'db' is a zone
725 * database. If type ==
726 * dns_rdatatype_any, then the
727 * node returned may contain, or
728 * consist entirely of invalid
729 * glue (i.e. data occluded by a
730 * zone cut). The caller must
731 * take care not to return invalid
734 * \li #DNS_R_DELEGATION The data requested is beneath
735 * a zone cut. node, foundname,
736 * and rdataset reference the
737 * NS RRset of the zone cut.
738 * If 'db' is a cache database,
739 * then this is the deepest known
742 * \li #DNS_R_ZONECUT type == dns_rdatatype_any, and
743 * the desired node is a zonecut.
744 * The caller must take care not
745 * to return inappropriate glue
746 * to a client. This result can
747 * only occur if 'db' is a zone
748 * database and DNS_DBFIND_GLUEOK
751 * \li #DNS_R_DNAME The data requested is beneath
752 * a DNAME. node, foundname,
753 * and rdataset reference the
756 * \li #DNS_R_CNAME The rdataset requested was not
757 * found, but there is a CNAME
758 * at the desired name. node,
759 * foundname, and rdataset
760 * reference the CNAME RRset.
762 * \li #DNS_R_NXDOMAIN The desired name does not
765 * \li #DNS_R_NXRRSET The desired name exists, but
766 * the desired type does not.
768 * \li #ISC_R_NOTFOUND The desired name does not
769 * exist, and no delegation could
770 * be found. This result can only
771 * occur if 'db' is a cache
772 * database. The caller should
773 * use its nameserver(s) of last
774 * resort (e.g. root hints).
776 * \li #DNS_R_NCACHENXDOMAIN The desired name does not
777 * exist. 'node' is bound to the
778 * cache node with the desired
779 * name, and 'rdataset' contains
780 * the negative caching proof.
782 * \li #DNS_R_NCACHENXRRSET The desired type does not
783 * exist. 'node' is bound to the
784 * cache node with the desired
785 * name, and 'rdataset' contains
786 * the negative caching proof.
788 * \li #DNS_R_EMPTYNAME The name exists but there is
789 * no data at the name.
791 * \li #DNS_R_COVERINGNSEC The returned data is a NSEC
792 * that potentially covers 'name'.
796 * \li #ISC_R_NOMEMORY
798 * \li #DNS_R_BADDB Data that is required to be
799 * present in the DB, e.g. an NSEC
800 * record in a secure zone, is not
803 * \li Other results are possible, and should all be treated as
808 dns_db_findzonecut(dns_db_t *db, dns_name_t *name,
809 unsigned int options, isc_stdtime_t now,
810 dns_dbnode_t **nodep, dns_name_t *foundname,
811 dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset);
813 * Find the deepest known zonecut which encloses 'name' in 'db'.
817 * \li If the #DNS_DBFIND_NOEXACT option is set, then the zonecut returned
818 * (if any) will be the deepest known ancestor of 'name'.
820 * \li If 'now' is zero, then the current time will be used.
824 * \li 'db' is a valid database with cache semantics.
826 * \li 'nodep' is NULL, or nodep is a valid pointer and *nodep == NULL.
828 * \li 'foundname' is a valid name with a dedicated buffer.
830 * \li 'rdataset' is NULL, or is a valid unassociated rdataset.
832 * Ensures, on a non-error completion:
834 * \li If nodep != NULL, then it is bound to the found node.
836 * \li If foundname != NULL, then it contains the full name of the
839 * \li If rdataset != NULL and type != dns_rdatatype_any, then
840 * rdataset is bound to the found rdataset.
842 * Non-error results are:
846 * \li #ISC_R_NOTFOUND
848 * \li Other results are possible, and should all be treated as
853 dns_db_attachnode(dns_db_t *db, dns_dbnode_t *source, dns_dbnode_t **targetp);
855 * Attach *targetp to source.
859 * \li 'db' is a valid database.
861 * \li 'source' is a valid node.
863 * \li 'targetp' points to a NULL dns_dbnode_t *.
867 * \li *targetp is attached to source.
871 dns_db_detachnode(dns_db_t *db, dns_dbnode_t **nodep);
873 * Detach *nodep from its node.
877 * \li 'db' is a valid database.
879 * \li 'nodep' points to a valid node.
883 * \li *nodep is NULL.
887 dns_db_expirenode(dns_db_t *db, dns_dbnode_t *node, isc_stdtime_t now);
889 * Mark as stale all records at 'node' which expire at or before 'now'.
891 * Note: if 'now' is zero, then the current time will be used.
895 * \li 'db' is a valid cache database.
897 * \li 'node' is a valid node.
901 dns_db_printnode(dns_db_t *db, dns_dbnode_t *node, FILE *out);
903 * Print a textual representation of the contents of the node to
906 * Note: this function is intended for debugging, not general use.
910 * \li 'db' is a valid database.
912 * \li 'node' is a valid node.
916 *** DB Iterator Creation
920 dns_db_createiterator(dns_db_t *db, isc_boolean_t relative_names,
921 dns_dbiterator_t **iteratorp);
923 * Create an iterator for version 'version' of 'db'.
927 * \li If 'relative_names' is ISC_TRUE, then node names returned by the
928 * iterator will be relative to the iterator's current origin. If
929 * #ISC_FALSE, then the node names will be absolute.
933 * \li 'db' is a valid database.
935 * \li iteratorp != NULL && *iteratorp == NULL
939 * \li On success, *iteratorp will be a valid database iterator.
944 * \li #ISC_R_NOMEMORY
952 * XXXRTH Should we check for glue and pending data in dns_db_findrdataset()?
956 dns_db_findrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
957 dns_rdatatype_t type, dns_rdatatype_t covers,
958 isc_stdtime_t now, dns_rdataset_t *rdataset,
959 dns_rdataset_t *sigrdataset);
961 * Search for an rdataset of type 'type' at 'node' that are in version
962 * 'version' of 'db'. If found, make 'rdataset' refer to it.
966 * \li If 'version' is NULL, then the current version will be used.
968 * \li Care must be used when using this routine to build a DNS response:
969 * 'node' should have been found with dns_db_find(), not
970 * dns_db_findnode(). No glue checking is done. No checking for
971 * pending data is done.
973 * \li The 'now' field is ignored if 'db' is a zone database. If 'db' is a
974 * cache database, an rdataset will not be found unless it expires after
975 * 'now'. If 'now' is zero, then the current time will be used.
979 * \li 'db' is a valid database.
981 * \li 'node' is a valid node.
983 * \li 'rdataset' is a valid, disassociated rdataset.
985 * \li 'sigrdataset' is a valid, disassociated rdataset, or it is NULL.
987 * \li If 'covers' != 0, 'type' must be SIG.
989 * \li 'type' is not a meta-RR type such as 'ANY' or 'OPT'.
993 * \li On success, 'rdataset' is associated with the found rdataset.
998 * \li #ISC_R_NOTFOUND
1000 * \li Other results are possible, depending upon the database
1001 * implementation used.
1005 dns_db_allrdatasets(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
1006 isc_stdtime_t now, dns_rdatasetiter_t **iteratorp);
1008 * Make '*iteratorp' an rdataset iteratator for all rdatasets at 'node' in
1009 * version 'version' of 'db'.
1013 * \li If 'version' is NULL, then the current version will be used.
1015 * \li The 'now' field is ignored if 'db' is a zone database. If 'db' is a
1016 * cache database, an rdataset will not be found unless it expires after
1017 * 'now'. Any ANY query will not match unless at least one rdataset at
1018 * the node expires after 'now'. If 'now' is zero, then the current time
1023 * \li 'db' is a valid database.
1025 * \li 'node' is a valid node.
1027 * \li iteratorp != NULL && *iteratorp == NULL
1031 * \li On success, '*iteratorp' is a valid rdataset iterator.
1035 * \li #ISC_R_SUCCESS
1036 * \li #ISC_R_NOTFOUND
1038 * \li Other results are possible, depending upon the database
1039 * implementation used.
1043 dns_db_addrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
1044 isc_stdtime_t now, dns_rdataset_t *rdataset,
1045 unsigned int options, dns_rdataset_t *addedrdataset);
1047 * Add 'rdataset' to 'node' in version 'version' of 'db'.
1051 * \li If the database has zone semantics, the #DNS_DBADD_MERGE option is set,
1052 * and an rdataset of the same type as 'rdataset' already exists at
1053 * 'node' then the contents of 'rdataset' will be merged with the existing
1054 * rdataset. If the option is not set, then rdataset will replace any
1055 * existing rdataset of the same type. If not merging and the
1056 * #DNS_DBADD_FORCE option is set, then the data will update the database
1057 * without regard to trust levels. If not forcing the data, then the
1058 * rdataset will only be added if its trust level is >= the trust level of
1059 * any existing rdataset. Forcing is only meaningful for cache databases.
1060 * If #DNS_DBADD_EXACT is set then there must be no rdata in common between
1061 * the old and new rdata sets. If #DNS_DBADD_EXACTTTL is set then both
1062 * the old and new rdata sets must have the same ttl.
1064 * \li The 'now' field is ignored if 'db' is a zone database. If 'db' is
1065 * a cache database, then the added rdataset will expire no later than
1066 * now + rdataset->ttl.
1068 * \li If 'addedrdataset' is not NULL, then it will be attached to the
1069 * resulting new rdataset in the database, or to the existing data if
1070 * the existing data was better.
1074 * \li 'db' is a valid database.
1076 * \li 'node' is a valid node.
1078 * \li 'rdataset' is a valid, associated rdataset with the same class
1081 * \li 'addedrdataset' is NULL, or a valid, unassociated rdataset.
1083 * \li The database has zone semantics and 'version' is a valid
1084 * read-write version, or the database has cache semantics
1085 * and version is NULL.
1087 * \li If the database has cache semantics, the #DNS_DBADD_MERGE option must
1092 * \li #ISC_R_SUCCESS
1093 * \li #DNS_R_UNCHANGED The operation did not change anything.
1094 * \li #ISC_R_NOMEMORY
1095 * \li #DNS_R_NOTEXACT
1097 * \li Other results are possible, depending upon the database
1098 * implementation used.
1102 dns_db_subtractrdataset(dns_db_t *db, dns_dbnode_t *node,
1103 dns_dbversion_t *version, dns_rdataset_t *rdataset,
1104 unsigned int options, dns_rdataset_t *newrdataset);
1106 * Remove any rdata in 'rdataset' from 'node' in version 'version' of
1111 * \li If 'newrdataset' is not NULL, then it will be attached to the
1112 * resulting new rdataset in the database, unless the rdataset has
1113 * become nonexistent. If DNS_DBSUB_EXACT is set then all elements
1114 * of 'rdataset' must exist at 'node'.
1118 * \li 'db' is a valid database.
1120 * \li 'node' is a valid node.
1122 * \li 'rdataset' is a valid, associated rdataset with the same class
1125 * \li 'newrdataset' is NULL, or a valid, unassociated rdataset.
1127 * \li The database has zone semantics and 'version' is a valid
1128 * read-write version.
1132 * \li #ISC_R_SUCCESS
1133 * \li #DNS_R_UNCHANGED The operation did not change anything.
1134 * \li #DNS_R_NXRRSET All rdata of the same type as those
1135 * in 'rdataset' have been deleted.
1136 * \li #DNS_R_NOTEXACT Some part of 'rdataset' did not
1137 * exist and DNS_DBSUB_EXACT was set.
1139 * \li Other results are possible, depending upon the database
1140 * implementation used.
1144 dns_db_deleterdataset(dns_db_t *db, dns_dbnode_t *node,
1145 dns_dbversion_t *version, dns_rdatatype_t type,
1146 dns_rdatatype_t covers);
1148 * Make it so that no rdataset of type 'type' exists at 'node' in version
1149 * version 'version' of 'db'.
1153 * \li If 'type' is dns_rdatatype_any, then no rdatasets will exist in
1154 * 'version' (provided that the dns_db_deleterdataset() isn't followed
1155 * by one or more dns_db_addrdataset() calls).
1159 * \li 'db' is a valid database.
1161 * \li 'node' is a valid node.
1163 * \li The database has zone semantics and 'version' is a valid
1164 * read-write version, or the database has cache semantics
1165 * and version is NULL.
1167 * \li 'type' is not a meta-RR type, except for dns_rdatatype_any, which is
1170 * \li If 'covers' != 0, 'type' must be SIG.
1174 * \li #ISC_R_SUCCESS
1175 * \li #DNS_R_UNCHANGED No rdatasets of 'type' existed before
1176 * the operation was attempted.
1178 * \li Other results are possible, depending upon the database
1179 * implementation used.
1183 dns_db_getsoaserial(dns_db_t *db, dns_dbversion_t *ver, isc_uint32_t *serialp);
1185 * Get the current SOA serial number from a zone database.
1188 * \li 'db' is a valid database with zone semantics.
1189 * \li 'ver' is a valid version.
1193 dns_db_overmem(dns_db_t *db, isc_boolean_t overmem);
1195 * Enable / disable agressive cache cleaning.
1199 dns_db_nodecount(dns_db_t *db);
1201 * Count the number of nodes in 'db'.
1205 * \li 'db' is a valid database.
1208 * \li The number of nodes in the database
1212 dns_db_settask(dns_db_t *db, isc_task_t *task);
1214 * If task is set then the final detach maybe performed asynchronously.
1217 * \li 'db' is a valid database.
1218 * \li 'task' to be valid or NULL.
1222 dns_db_ispersistent(dns_db_t *db);
1224 * Is 'db' persistent? A persistent database does not need to be loaded
1225 * from disk or written to disk.
1229 * \li 'db' is a valid database.
1232 * \li #ISC_TRUE 'db' is persistent.
1233 * \li #ISC_FALSE 'db' is not persistent.
1237 dns_db_register(const char *name, dns_dbcreatefunc_t create, void *driverarg,
1238 isc_mem_t *mctx, dns_dbimplementation_t **dbimp);
1241 * Register a new database implementation and add it to the list of
1242 * supported implementations.
1246 * \li 'name' is not NULL
1247 * \li 'order' is a valid function pointer
1248 * \li 'mctx' is a valid memory context
1249 * \li dbimp != NULL && *dbimp == NULL
1252 * \li #ISC_R_SUCCESS The registration succeeded
1253 * \li #ISC_R_NOMEMORY Out of memory
1254 * \li #ISC_R_EXISTS A database implementation with the same name exists
1258 * \li *dbimp points to an opaque structure which must be passed to
1259 * dns_db_unregister().
1263 dns_db_unregister(dns_dbimplementation_t **dbimp);
1265 * Remove a database implementation from the the list of supported
1266 * implementations. No databases of this type can be active when this
1270 * \li dbimp != NULL && *dbimp == NULL
1274 * \li Any memory allocated in *dbimp will be freed.
1278 dns_db_getoriginnode(dns_db_t *db, dns_dbnode_t **nodep);
1280 * Get the origin DB node corresponding to the DB's zone. This function
1281 * should typically succeed unless the underlying DB implementation doesn't
1282 * support the feature.
1286 * \li 'db' is a valid zone database.
1287 * \li 'nodep' != NULL && '*nodep' == NULL
1290 * \li On success, '*nodep' will point to the DB node of the zone's origin.
1293 * \li #ISC_R_SUCCESS
1294 * \li #ISC_R_NOTFOUND - the DB implementation does not support this feature.
1299 #endif /* DNS_DB_H */