2 * Copyright (C) 2004-2009 Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (C) 1999-2002 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: rbt.h,v 1.77 2009/11/04 01:18:19 marka Exp $ */
23 /*! \file dns/rbt.h */
26 #include <isc/magic.h>
27 #include <isc/refcount.h>
29 #include <dns/types.h>
33 #define DNS_RBT_USEHASH 1
37 * Option values for dns_rbt_findnode() and dns_rbt_findname().
38 * These are used to form a bitmask.
40 #define DNS_RBTFIND_NOOPTIONS 0x00
41 #define DNS_RBTFIND_EMPTYDATA 0x01
42 #define DNS_RBTFIND_NOEXACT 0x02
43 #define DNS_RBTFIND_NOPREDECESSOR 0x04
46 #ifndef DNS_RBT_USEISCREFCOUNT
47 #ifdef ISC_REFCOUNT_HAVEATOMIC
48 #define DNS_RBT_USEISCREFCOUNT 1
53 * These should add up to 30.
55 #define DNS_RBT_LOCKLENGTH 10
56 #define DNS_RBT_REFLENGTH 20
58 #define DNS_RBTNODE_MAGIC ISC_MAGIC('R','B','N','O')
60 #define DNS_RBTNODE_VALID(n) ISC_MAGIC_VALID(n, DNS_RBTNODE_MAGIC)
62 #define DNS_RBTNODE_VALID(n) ISC_TRUE
66 * This is the structure that is used for each node in the red/black
67 * tree of trees. NOTE WELL: the implementation manages this as a variable
68 * length structure, with the actual wire-format name and other data
69 * appended to this structure. Allocating a contiguous block of memory for
70 * multiple dns_rbtnode structures will not work.
72 typedef struct dns_rbtnode dns_rbtnode_t;
74 DNS_RBT_NSEC_NORMAL=0, /* in main tree */
75 DNS_RBT_NSEC_HAS_NSEC=1, /* also has node in nsec tree */
76 DNS_RBT_NSEC_NSEC=2, /* in nsec tree */
77 DNS_RBT_NSEC_NSEC3=3 /* in nsec3 tree */
83 dns_rbtnode_t *parent;
87 #ifdef DNS_RBT_USEHASH
88 dns_rbtnode_t *hashnext;
92 * Used for LRU cache. This linked list is used to mark nodes which
93 * have no data any longer, but we cannot unlink at that exact moment
94 * because we did not or could not obtain a write lock on the tree.
96 ISC_LINK(dns_rbtnode_t) deadlink;
100 * The following bitfields add up to a total bitwidth of 32.
101 * The range of values necessary for each item is indicated,
102 * but in the case of "attributes" the field is wider to accommodate
103 * possible future expansion.
105 * In each case below the "range" indicated is what's _necessary_ for
106 * the bitfield to hold, not what it actually _can_ hold.
108 unsigned int is_root : 1; /*%< range is 0..1 */
109 unsigned int color : 1; /*%< range is 0..1 */
110 unsigned int find_callback : 1; /*%< range is 0..1 */
111 unsigned int attributes : 3; /*%< range is 0..2 */
112 unsigned int nsec : 2; /*%< range is 0..3 */
113 unsigned int namelen : 8; /*%< range is 1..255 */
114 unsigned int offsetlen : 8; /*%< range is 1..128 */
115 unsigned int oldnamelen : 8; /*%< range is 1..255 */
118 #ifdef DNS_RBT_USEHASH
119 unsigned int hashval;
124 * These values are used in the RBT DB implementation. The appropriate
125 * node lock must be held before accessing them.
128 unsigned int dirty:1;
130 unsigned int locknum:DNS_RBT_LOCKLENGTH;
131 #ifndef DNS_RBT_USEISCREFCOUNT
132 unsigned int references:DNS_RBT_REFLENGTH;
134 isc_refcount_t references; /* note that this is not in the bitfield */
139 typedef isc_result_t (*dns_rbtfindcallback_t)(dns_rbtnode_t *node,
148 * A chain is used to keep track of the sequence of nodes to reach any given
149 * node from the root of the tree. Originally nodes did not have parent
150 * pointers in them (for memory usage reasons) so there was no way to find
151 * the path back to the root from any given node. Now that nodes have parent
152 * pointers, chains might be going away in a future release, though the
153 * movement functionality would remain.
155 * In any event, parent information, whether via parent pointers or chains, is
156 * necessary information for iterating through the tree or for basic internal
157 * tree maintenance issues (ie, the rotations that are done to rebalance the
158 * tree when a node is added). The obvious implication of this is that for a
159 * chain to remain valid, the tree has to be locked down against writes for the
160 * duration of the useful life of the chain, because additions or removals can
161 * change the path from the root to the node the chain has targeted.
163 * The dns_rbtnodechain_ functions _first, _last, _prev and _next all take
164 * dns_name_t parameters for the name and the origin, which can be NULL. If
165 * non-NULL, 'name' will end up pointing to the name data and offsets that are
166 * stored at the node (and thus it will be read-only), so it should be a
167 * regular dns_name_t that has been initialized with dns_name_init. When
168 * 'origin' is non-NULL, it will get the name of the origin stored in it, so it
169 * needs to have its own buffer space and offsets, which is most easily
170 * accomplished with a dns_fixedname_t. It is _not_ necessary to reinitialize
171 * either 'name' or 'origin' between calls to the chain functions.
173 * NOTE WELL: even though the name data at the root of the tree of trees will
174 * be absolute (typically just "."), it will will be made into a relative name
175 * with an origin of "." -- an empty name when the node is ".". This is
176 * because a common on operation on 'name' and 'origin' is to use
177 * dns_name_concatenate() on them to generate the complete name. An empty name
178 * can be detected when dns_name_countlabels == 0, and is printed by
179 * dns_name_totext()/dns_name_format() as "@", consistent with RFC1035's
180 * definition of "@" as the current origin.
182 * dns_rbtnodechain_current is similar to the _first, _last, _prev and _next
183 * functions but additionally can provide the node to which the chain points.
187 * The number of level blocks to allocate at a time. Currently the maximum
188 * number of levels is allocated directly in the structure, but future
189 * revisions of this code might have a static initial block with dynamic
190 * growth. Allocating space for 256 levels when the tree is almost never that
191 * deep is wasteful, but it's not clear that it matters, since the waste is
192 * only 2MB for 1000 concurrently active chains on a system with 64-bit
195 #define DNS_RBT_LEVELBLOCK 254
197 typedef struct dns_rbtnodechain {
201 * The terminal node of the chain. It is not in levels[].
202 * This is ostensibly private ... but in a pinch it could be
203 * used tell that the chain points nowhere without needing to
204 * call dns_rbtnodechain_current().
208 * The maximum number of labels in a name is 128; bitstrings mean
209 * a conceptually very large number (which I have not bothered to
210 * compute) of logical levels because splitting can potentially occur
211 * at each bit. However, DNSSEC restricts the number of "logical"
212 * labels in a name to 255, meaning only 254 pointers are needed
215 dns_rbtnode_t * levels[DNS_RBT_LEVELBLOCK];
217 * level_count indicates how deep the chain points into the
218 * tree of trees, and is the index into the levels[] array.
219 * Thus, levels[level_count - 1] is the last level node stored.
220 * A chain that points to the top level of the tree of trees has
221 * a level_count of 0, the first level has a level_count of 1, and
224 unsigned int level_count;
226 * level_matches tells how many levels matched above the node
227 * returned by dns_rbt_findnode(). A match (partial or exact) found
228 * in the first level thus results in level_matches being set to 1.
229 * This is used by the rbtdb to set the start point for a recursive
230 * search of superdomains until the RR it is looking for is found.
232 unsigned int level_matches;
233 } dns_rbtnodechain_t;
236 ***** Public interfaces.
239 dns_rbt_create(isc_mem_t *mctx, void (*deleter)(void *, void *),
240 void *deleter_arg, dns_rbt_t **rbtp);
242 * Initialize a red-black tree of trees.
245 *\li The deleter argument, if non-null, points to a function that is
246 * responsible for cleaning up any memory associated with the data
247 * pointer of a node when the node is deleted. It is passed the
248 * deleted node's data pointer as its first argument and deleter_arg
249 * as its second argument.
252 * \li mctx is a pointer to a valid memory context.
253 *\li rbtp != NULL && *rbtp == NULL
254 *\li arg == NULL iff deleter == NULL
257 *\li If result is ISC_R_SUCCESS:
258 * *rbtp points to a valid red-black tree manager
260 *\li If result is failure:
261 * *rbtp does not point to a valid red-black tree manager.
264 *\li #ISC_R_SUCCESS Success
265 *\li #ISC_R_NOMEMORY Resource limit: Out of Memory
269 dns_rbt_addname(dns_rbt_t *rbt, dns_name_t *name, void *data);
271 * Add 'name' to the tree of trees, associated with 'data'.
274 *\li 'data' is never required to be non-NULL, but specifying it
275 * when the name is added is faster than searching for 'name'
276 * again and then setting the data pointer. The lack of a data pointer
277 * for a node also has other ramifications regarding whether
278 * dns_rbt_findname considers a node to exist, or dns_rbt_deletename
282 *\li rbt is a valid rbt manager.
283 *\li dns_name_isabsolute(name) == TRUE
286 *\li 'name' is not altered in any way.
288 *\li Any external references to nodes in the tree are unaffected by
289 * node splits that are necessary to insert the new name.
291 *\li If result is #ISC_R_SUCCESS:
292 * 'name' is findable in the red/black tree of trees in O(log N).
293 * The data pointer of the node for 'name' is set to 'data'.
295 *\li If result is #ISC_R_EXISTS or #ISC_R_NOSPACE:
296 * The tree of trees is unaltered.
298 *\li If result is #ISC_R_NOMEMORY:
302 *\li #ISC_R_SUCCESS Success
303 *\li #ISC_R_EXISTS The name already exists with associated data.
304 *\li #ISC_R_NOSPACE The name had more logical labels than are allowed.
305 *\li #ISC_R_NOMEMORY Resource Limit: Out of Memory
309 dns_rbt_addnode(dns_rbt_t *rbt, dns_name_t *name, dns_rbtnode_t **nodep);
312 * Just like dns_rbt_addname, but returns the address of the node.
315 *\li rbt is a valid rbt structure.
316 *\li dns_name_isabsolute(name) == TRUE
317 *\li nodep != NULL && *nodep == NULL
320 *\li 'name' is not altered in any way.
322 *\li Any external references to nodes in the tree are unaffected by
323 * node splits that are necessary to insert the new name.
325 *\li If result is ISC_R_SUCCESS:
326 * 'name' is findable in the red/black tree of trees in O(log N).
327 * *nodep is the node that was added for 'name'.
329 *\li If result is ISC_R_EXISTS:
330 * The tree of trees is unaltered.
331 * *nodep is the existing node for 'name'.
333 *\li If result is ISC_R_NOMEMORY:
337 *\li #ISC_R_SUCCESS Success
338 *\li #ISC_R_EXISTS The name already exists, possibly without data.
339 *\li #ISC_R_NOMEMORY Resource Limit: Out of Memory
343 dns_rbt_findname(dns_rbt_t *rbt, dns_name_t *name, unsigned int options,
344 dns_name_t *foundname, void **data);
346 * Get the data pointer associated with 'name'.
349 *\li When #DNS_RBTFIND_NOEXACT is set, the closest matching superdomain is
350 * returned (also subject to #DNS_RBTFIND_EMPTYDATA), even when there is
351 * an exact match in the tree.
353 *\li A node that has no data is considered not to exist for this function,
354 * unless the #DNS_RBTFIND_EMPTYDATA option is set.
357 *\li rbt is a valid rbt manager.
358 *\li dns_name_isabsolute(name) == TRUE
359 *\li data != NULL && *data == NULL
362 *\li 'name' and the tree are not altered in any way.
364 *\li If result is ISC_R_SUCCESS:
365 * *data is the data associated with 'name'.
367 *\li If result is DNS_R_PARTIALMATCH:
368 * *data is the data associated with the deepest superdomain
369 * of 'name' which has data.
371 *\li If result is ISC_R_NOTFOUND:
372 * Neither the name nor a superdomain was found with data.
375 *\li #ISC_R_SUCCESS Success
376 *\li #DNS_R_PARTIALMATCH Superdomain found with data
377 *\li #ISC_R_NOTFOUND No match
378 *\li #ISC_R_NOSPACE Concatenating nodes to form foundname failed
382 dns_rbt_findnode(dns_rbt_t *rbt, dns_name_t *name, dns_name_t *foundname,
383 dns_rbtnode_t **node, dns_rbtnodechain_t *chain,
384 unsigned int options, dns_rbtfindcallback_t callback,
387 * Find the node for 'name'.
390 *\li A node that has no data is considered not to exist for this function,
391 * unless the DNS_RBTFIND_EMPTYDATA option is set. This applies to both
392 * exact matches and partial matches.
394 *\li If the chain parameter is non-NULL, then the path through the tree
395 * to the DNSSEC predecessor of the searched for name is maintained,
396 * unless the DNS_RBTFIND_NOPREDECESSOR or DNS_RBTFIND_NOEXACT option
397 * is used. (For more details on those options, see below.)
399 *\li If there is no predecessor, then the chain will point to nowhere, as
400 * indicated by chain->end being NULL or dns_rbtnodechain_current
401 * returning ISC_R_NOTFOUND. Note that in a normal Internet DNS RBT
402 * there will always be a predecessor for all names except the root
403 * name, because '.' will exist and '.' is the predecessor of
404 * everything. But you can certainly construct a trivial tree and a
405 * search for it that has no predecessor.
407 *\li Within the chain structure, the 'levels' member of the structure holds
408 * the root node of each level except the first.
410 *\li The 'level_count' of the chain indicates how deep the chain to the
411 * predecessor name is, as an index into the 'levels[]' array. It does
412 * not count name elements, per se, but only levels of the tree of trees,
413 * the distinction arising because multiple labels from a name can be
414 * stored on only one level. It is also does not include the level
415 * that has the node, since that level is not stored in levels[].
417 *\li The chain's 'level_matches' is not directly related to the predecessor.
418 * It is the number of levels above the level of the found 'node',
419 * regardless of whether it was a partial match or exact match. When
420 * the node is found in the top level tree, or no node is found at all,
421 * level_matches is 0.
423 *\li When DNS_RBTFIND_NOEXACT is set, the closest matching superdomain is
424 * returned (also subject to DNS_RBTFIND_EMPTYDATA), even when
425 * there is an exact match in the tree. In this case, the chain
426 * will not point to the DNSSEC predecessor, but will instead point
427 * to the exact match, if there was any. Thus the preceding paragraphs
428 * should have "exact match" substituted for "predecessor" to describe
429 * how the various elements of the chain are set. This was done to
430 * ensure that the chain's state was sane, and to prevent problems that
431 * occurred when running the predecessor location code under conditions
432 * it was not designed for. It is not clear *where* the chain should
433 * point when DNS_RBTFIND_NOEXACT is set, so if you end up using a chain
434 * with this option because you want a particular node, let us know
435 * where you want the chain pointed, so this can be made more firm.
438 *\li rbt is a valid rbt manager.
439 *\li dns_name_isabsolute(name) == TRUE.
440 *\li node != NULL && *node == NULL.
441 *\li #DNS_RBTFIND_NOEXACT and DNS_RBTFIND_NOPREDECESSOR are mutually
445 *\li 'name' and the tree are not altered in any way.
447 *\li If result is ISC_R_SUCCESS:
449 * *node is the terminal node for 'name'.
451 * 'foundname' and 'name' represent the same name (though not
454 * 'chain' points to the DNSSEC predecessor, if any, of 'name'.
456 * chain->level_matches and chain->level_count are equal.
459 * If result is DNS_R_PARTIALMATCH:
461 * *node is the data associated with the deepest superdomain
462 * of 'name' which has data.
464 * 'foundname' is the name of deepest superdomain (which has
465 * data, unless the DNS_RBTFIND_EMPTYDATA option is set).
467 * 'chain' points to the DNSSEC predecessor, if any, of 'name'.
470 *\li If result is ISC_R_NOTFOUND:
472 * Neither the name nor a superdomain was found. *node is NULL.
474 * 'chain' points to the DNSSEC predecessor, if any, of 'name'.
476 * chain->level_matches is 0.
480 *\li #ISC_R_SUCCESS Success
481 *\li #DNS_R_PARTIALMATCH Superdomain found with data
482 *\li #ISC_R_NOTFOUND No match, or superdomain with no data
483 *\li #ISC_R_NOSPACE Concatenating nodes to form foundname failed
487 dns_rbt_deletename(dns_rbt_t *rbt, dns_name_t *name, isc_boolean_t recurse);
489 * Delete 'name' from the tree of trees.
492 *\li When 'name' is removed, if recurse is ISC_TRUE then all of its
493 * subnames are removed too.
496 *\li rbt is a valid rbt manager.
497 *\li dns_name_isabsolute(name) == TRUE
500 *\li 'name' is not altered in any way.
502 *\li Does NOT ensure that any external references to nodes in the tree
503 * are unaffected by node joins.
505 *\li If result is ISC_R_SUCCESS:
506 * 'name' does not appear in the tree with data; however,
507 * the node for the name might still exist which can be
508 * found with dns_rbt_findnode (but not dns_rbt_findname).
510 *\li If result is ISC_R_NOTFOUND:
511 * 'name' does not appear in the tree with data, because
512 * it did not appear in the tree before the function was called.
514 *\li If result is something else:
515 * See result codes for dns_rbt_findnode (if it fails, the
516 * node is not deleted) or dns_rbt_deletenode (if it fails,
517 * the node is deleted, but the tree is not optimized when
518 * it could have been).
521 *\li #ISC_R_SUCCESS Success
522 *\li #ISC_R_NOTFOUND No match
523 *\li something_else Any return code from dns_rbt_findnode except
524 * DNS_R_PARTIALMATCH (which causes ISC_R_NOTFOUND
525 * to be returned instead), and any code from
526 * dns_rbt_deletenode.
530 dns_rbt_deletenode(dns_rbt_t *rbt, dns_rbtnode_t *node, isc_boolean_t recurse);
532 * Delete 'node' from the tree of trees.
535 *\li When 'node' is removed, if recurse is ISC_TRUE then all nodes
536 * in levels down from it are removed too.
539 *\li rbt is a valid rbt manager.
543 *\li Does NOT ensure that any external references to nodes in the tree
544 * are unaffected by node joins.
546 *\li If result is ISC_R_SUCCESS:
547 * 'node' does not appear in the tree with data; however,
548 * the node might still exist if it serves as a pointer to
549 * a lower tree level as long as 'recurse' was false, hence
550 * the node could can be found with dns_rbt_findnode when
551 * that function's empty_data_ok parameter is true.
553 *\li If result is ISC_R_NOMEMORY or ISC_R_NOSPACE:
554 * The node was deleted, but the tree structure was not
558 *\li #ISC_R_SUCCESS Success
559 *\li #ISC_R_NOMEMORY Resource Limit: Out of Memory when joining nodes.
560 *\li #ISC_R_NOSPACE dns_name_concatenate failed when joining nodes.
564 dns_rbt_namefromnode(dns_rbtnode_t *node, dns_name_t *name);
566 * Convert the sequence of labels stored at 'node' into a 'name'.
569 *\li This function does not return the full name, from the root, but
570 * just the labels at the indicated node.
572 *\li The name data pointed to by 'name' is the information stored
573 * in the node, not a copy. Altering the data at this pointer
574 * will likely cause grief.
577 * \li name->offsets == NULL
580 * \li 'name' is DNS_NAMEATTR_READONLY.
582 * \li 'name' will point directly to the labels stored after the
583 * dns_rbtnode_t struct.
585 * \li 'name' will have offsets that also point to the information stored
586 * as part of the node.
590 dns_rbt_fullnamefromnode(dns_rbtnode_t *node, dns_name_t *name);
592 * Like dns_rbt_namefromnode, but returns the full name from the root.
595 * \li Unlike dns_rbt_namefromnode, the name will not point directly
596 * to node data. Rather, dns_name_concatenate will be used to copy
597 * the name data from each node into the 'name' argument.
601 * \li name has a dedicated buffer.
605 * \li ISC_R_NOSPACE (possible via dns_name_concatenate)
606 * \li DNS_R_NAMETOOLONG (possible via dns_name_concatenate)
610 dns_rbt_formatnodename(dns_rbtnode_t *node, char *printname,
613 * Format the full name of a node for printing, using dns_name_format().
616 * \li 'size' is the length of the printname buffer. This should be
617 * DNS_NAME_FORMATSIZE or larger.
620 * \li node and printname are not NULL.
623 * \li The 'printname' pointer.
627 dns_rbt_nodecount(dns_rbt_t *rbt);
629 * Obtain the number of nodes in the tree of trees.
632 * \li rbt is a valid rbt manager.
636 dns_rbt_destroy(dns_rbt_t **rbtp);
638 dns_rbt_destroy2(dns_rbt_t **rbtp, unsigned int quantum);
640 * Stop working with a red-black tree of trees.
641 * If 'quantum' is zero then the entire tree will be destroyed.
642 * If 'quantum' is non zero then up to 'quantum' nodes will be destroyed
643 * allowing the rbt to be incrementally destroyed by repeated calls to
644 * dns_rbt_destroy2(). Once dns_rbt_destroy2() has been called no other
645 * operations than dns_rbt_destroy()/dns_rbt_destroy2() should be
646 * performed on the tree of trees.
649 * \li *rbt is a valid rbt manager.
651 * Ensures on ISC_R_SUCCESS:
652 * \li All space allocated by the RBT library has been returned.
654 * \li *rbt is invalidated as an rbt manager.
658 * \li ISC_R_QUOTA if 'quantum' nodes have been destroyed.
662 dns_rbt_printall(dns_rbt_t *rbt);
664 * Print an ASCII representation of the internal structure of the red-black
668 * \li The name stored at each node, along with the node's color, is printed.
669 * Then the down pointer, left and right pointers are displayed
670 * recursively in turn. NULL down pointers are silently omitted;
671 * NULL left and right pointers are printed.
675 ***** Chain Functions
679 dns_rbtnodechain_init(dns_rbtnodechain_t *chain, isc_mem_t *mctx);
681 * Initialize 'chain'.
684 *\li 'chain' is a valid pointer.
686 *\li 'mctx' is a valid memory context.
689 *\li 'chain' is suitable for use.
693 dns_rbtnodechain_reset(dns_rbtnodechain_t *chain);
695 * Free any dynamic storage associated with 'chain', and then reinitialize
699 *\li 'chain' is a valid pointer.
702 *\li 'chain' is suitable for use, and uses no dynamic storage.
706 dns_rbtnodechain_invalidate(dns_rbtnodechain_t *chain);
708 * Free any dynamic storage associated with 'chain', and then invalidates it.
711 *\li Future calls to any dns_rbtnodechain_ function will need to call
712 * dns_rbtnodechain_init on the chain first (except, of course,
713 * dns_rbtnodechain_init itself).
716 *\li 'chain' is a valid chain.
719 *\li 'chain' is no longer suitable for use, and uses no dynamic storage.
723 dns_rbtnodechain_current(dns_rbtnodechain_t *chain, dns_name_t *name,
724 dns_name_t *origin, dns_rbtnode_t **node);
726 * Provide the name, origin and node to which the chain is currently pointed.
729 *\li The tree need not have be locked against additions for the chain
730 * to remain valid, however there are no guarantees if any deletion
731 * has been made since the chain was established.
734 *\li 'chain' is a valid chain.
737 *\li 'node', if non-NULL, is the node to which the chain was pointed
738 * by dns_rbt_findnode, dns_rbtnodechain_first or dns_rbtnodechain_last.
739 * If none were called for the chain since it was initialized or reset,
740 * or if the was no predecessor to the name searched for with
741 * dns_rbt_findnode, then '*node' is NULL and ISC_R_NOTFOUND is returned.
743 *\li 'name', if non-NULL, is the name stored at the terminal level of
744 * the chain. This is typically a single label, like the "www" of
745 * "www.isc.org", but need not be so. At the root of the tree of trees,
746 * if the node is "." then 'name' is ".", otherwise it is relative to ".".
747 * (Minimalist and atypical case: if the tree has just the name
748 * "isc.org." then the root node's stored name is "isc.org." but 'name'
749 * will be "isc.org".)
751 *\li 'origin', if non-NULL, is the sequence of labels in the levels
752 * above the terminal level, such as "isc.org." in the above example.
753 * 'origin' is always "." for the root node.
757 *\li #ISC_R_SUCCESS name, origin & node were successfully set.
758 *\li #ISC_R_NOTFOUND The chain does not point to any node.
759 *\li <something_else> Any error return from dns_name_concatenate.
763 dns_rbtnodechain_first(dns_rbtnodechain_t *chain, dns_rbt_t *rbt,
764 dns_name_t *name, dns_name_t *origin);
766 * Set the chain to the lexically first node in the tree of trees.
769 *\li By the definition of ordering for DNS names, the root of the tree of
770 * trees is the very first node, since everything else in the megatree
771 * uses it as a common suffix.
774 *\li 'chain' is a valid chain.
775 *\li 'rbt' is a valid rbt manager.
778 *\li The chain points to the very first node of the tree.
780 *\li 'name' and 'origin', if non-NULL, are set as described for
781 * dns_rbtnodechain_current. Thus 'origin' will always be ".".
784 *\li #DNS_R_NEWORIGIN The name & origin were successfully set.
785 *\li <something_else> Any error result from dns_rbtnodechain_current.
789 dns_rbtnodechain_last(dns_rbtnodechain_t *chain, dns_rbt_t *rbt,
790 dns_name_t *name, dns_name_t *origin);
792 * Set the chain to the lexically last node in the tree of trees.
795 *\li 'chain' is a valid chain.
796 *\li 'rbt' is a valid rbt manager.
799 *\li The chain points to the very last node of the tree.
801 *\li 'name' and 'origin', if non-NULL, are set as described for
802 * dns_rbtnodechain_current.
805 *\li #DNS_R_NEWORIGIN The name & origin were successfully set.
806 *\li #ISC_R_NOMEMORY Resource Limit: Out of Memory building chain.
807 *\li <something_else> Any error result from dns_name_concatenate.
811 dns_rbtnodechain_prev(dns_rbtnodechain_t *chain, dns_name_t *name,
814 * Adjusts chain to point the DNSSEC predecessor of the name to which it
815 * is currently pointed.
818 *\li 'chain' is a valid chain.
819 *\li 'chain' has been pointed somewhere in the tree with dns_rbt_findnode,
820 * dns_rbtnodechain_first or dns_rbtnodechain_last -- and remember that
821 * dns_rbt_findnode is not guaranteed to point the chain somewhere,
822 * since there may have been no predecessor to the searched for name.
825 *\li The chain is pointed to the predecessor of its current target.
827 *\li 'name' and 'origin', if non-NULL, are set as described for
828 * dns_rbtnodechain_current.
830 *\li 'origin' is only if a new origin was found.
833 *\li #ISC_R_SUCCESS The predecessor was found and 'name' was set.
834 *\li #DNS_R_NEWORIGIN The predecessor was found with a different
835 * origin and 'name' and 'origin' were set.
836 *\li #ISC_R_NOMORE There was no predecessor.
837 *\li <something_else> Any error result from dns_rbtnodechain_current.
841 dns_rbtnodechain_next(dns_rbtnodechain_t *chain, dns_name_t *name,
844 * Adjusts chain to point the DNSSEC successor of the name to which it
845 * is currently pointed.
848 *\li 'chain' is a valid chain.
849 *\li 'chain' has been pointed somewhere in the tree with dns_rbt_findnode,
850 * dns_rbtnodechain_first or dns_rbtnodechain_last -- and remember that
851 * dns_rbt_findnode is not guaranteed to point the chain somewhere,
852 * since there may have been no predecessor to the searched for name.
855 *\li The chain is pointed to the successor of its current target.
857 *\li 'name' and 'origin', if non-NULL, are set as described for
858 * dns_rbtnodechain_current.
860 *\li 'origin' is only if a new origin was found.
863 *\li #ISC_R_SUCCESS The successor was found and 'name' was set.
864 *\li #DNS_R_NEWORIGIN The successor was found with a different
865 * origin and 'name' and 'origin' were set.
866 *\li #ISC_R_NOMORE There was no successor.
867 *\li <something_else> Any error result from dns_name_concatenate.
871 dns_rbtnodechain_down(dns_rbtnodechain_t *chain, dns_name_t *name,
874 * Descend down if possible.
878 dns_rbtnodechain_nextflat(dns_rbtnodechain_t *chain, dns_name_t *name);
880 * Find the next node at the current depth in DNSSEC order.
884 * Wrapper macros for manipulating the rbtnode reference counter:
885 * Since we selectively use isc_refcount_t for the reference counter of
886 * a rbtnode, operations on the counter depend on the actual type of it.
887 * The following macros provide a common interface to these operations,
888 * hiding the back-end. The usage is the same as that of isc_refcount_xxx().
890 #ifdef DNS_RBT_USEISCREFCOUNT
891 #define dns_rbtnode_refinit(node, n) \
893 isc_refcount_init(&(node)->references, (n)); \
895 #define dns_rbtnode_refdestroy(node) \
897 isc_refcount_destroy(&(node)->references); \
899 #define dns_rbtnode_refcurrent(node) \
900 isc_refcount_current(&(node)->references)
901 #define dns_rbtnode_refincrement0(node, refs) \
903 isc_refcount_increment0(&(node)->references, (refs)); \
905 #define dns_rbtnode_refincrement(node, refs) \
907 isc_refcount_increment(&(node)->references, (refs)); \
909 #define dns_rbtnode_refdecrement(node, refs) \
911 isc_refcount_decrement(&(node)->references, (refs)); \
913 #else /* DNS_RBT_USEISCREFCOUNT */
914 #define dns_rbtnode_refinit(node, n) ((node)->references = (n))
915 #define dns_rbtnode_refdestroy(node) REQUIRE((node)->references == 0)
916 #define dns_rbtnode_refcurrent(node) ((node)->references)
917 #define dns_rbtnode_refincrement0(node, refs) \
919 unsigned int *_tmp = (unsigned int *)(refs); \
920 (node)->references++; \
921 if ((_tmp) != NULL) \
922 (*_tmp) = (node)->references; \
924 #define dns_rbtnode_refincrement(node, refs) \
926 REQUIRE((node)->references > 0); \
927 (node)->references++; \
928 if ((refs) != NULL) \
929 (*refs) = (node)->references; \
931 #define dns_rbtnode_refdecrement(node, refs) \
933 REQUIRE((node)->references > 0); \
934 (node)->references--; \
935 if ((refs) != NULL) \
936 (*refs) = (node)->references; \
938 #endif /* DNS_RBT_USEISCREFCOUNT */
942 #endif /* DNS_RBT_H */