2 * Copyright (C) 2004, 2005 Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (C) 1999-2002 Internet Software Consortium.
5 * Permission to use, copy, modify, and 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 1.59.18.5 2005/10/13 01:26:07 marka Exp $ */
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 {
76 struct dns_rbtnode *parent;
77 struct dns_rbtnode *left;
78 struct dns_rbtnode *right;
79 struct dns_rbtnode *down;
80 #ifdef DNS_RBT_USEHASH
81 struct dns_rbtnode *hashnext;
85 * The following bitfields add up to a total bitwidth of 32.
86 * The range of values necessary for each item is indicated,
87 * but in the case of "attributes" the field is wider to accomodate
88 * possible future expansion. "offsetlen" could be one bit
89 * narrower by always adjusting its value by 1 to find the real
90 * offsetlen, but doing so does not gain anything (except perhaps
91 * another bit for "attributes", which doesn't yet need any more).
93 * In each case below the "range" indicated is what's _necessary_ for
94 * the bitfield to hold, not what it actually _can_ hold.
96 unsigned int is_root : 1; /*%< range is 0..1 */
97 unsigned int color : 1; /*%< range is 0..1 */
98 unsigned int find_callback : 1; /*%< range is 0..1 */
99 unsigned int attributes : 4; /*%< range is 0..2 */
100 unsigned int namelen : 8; /*%< range is 1..255 */
101 unsigned int offsetlen : 8; /*%< range is 1..128 */
102 unsigned int padbytes : 9; /*%< range is 0..380 */
105 #ifdef DNS_RBT_USEHASH
106 unsigned int hashval;
111 * These values are used in the RBT DB implementation. The appropriate
112 * node lock must be held before accessing them.
115 unsigned int dirty:1;
117 unsigned int locknum:DNS_RBT_LOCKLENGTH;
118 #ifndef DNS_RBT_USEISCREFCOUNT
119 unsigned int references:DNS_RBT_REFLENGTH;
121 isc_refcount_t references; /* note that this is not in the bitfield */
126 typedef isc_result_t (*dns_rbtfindcallback_t)(dns_rbtnode_t *node,
135 * A chain is used to keep track of the sequence of nodes to reach any given
136 * node from the root of the tree. Originally nodes did not have parent
137 * pointers in them (for memory usage reasons) so there was no way to find
138 * the path back to the root from any given node. Now that nodes have parent
139 * pointers, chains might be going away in a future release, though the
140 * movement functionality would remain.
142 * In any event, parent information, whether via parent pointers or chains, is
143 * necessary information for iterating through the tree or for basic internal
144 * tree maintenance issues (ie, the rotations that are done to rebalance the
145 * tree when a node is added). The obvious implication of this is that for a
146 * chain to remain valid, the tree has to be locked down against writes for the
147 * duration of the useful life of the chain, because additions or removals can
148 * change the path from the root to the node the chain has targetted.
150 * The dns_rbtnodechain_ functions _first, _last, _prev and _next all take
151 * dns_name_t parameters for the name and the origin, which can be NULL. If
152 * non-NULL, 'name' will end up pointing to the name data and offsets that are
153 * stored at the node (and thus it will be read-only), so it should be a
154 * regular dns_name_t that has been initialized with dns_name_init. When
155 * 'origin' is non-NULL, it will get the name of the origin stored in it, so it
156 * needs to have its own buffer space and offsets, which is most easily
157 * accomplished with a dns_fixedname_t. It is _not_ necessary to reinitialize
158 * either 'name' or 'origin' between calls to the chain functions.
160 * NOTE WELL: even though the name data at the root of the tree of trees will
161 * be absolute (typically just "."), it will will be made into a relative name
162 * with an origin of "." -- an empty name when the node is ".". This is
163 * because a common on operation on 'name' and 'origin' is to use
164 * dns_name_concatenate() on them to generate the complete name. An empty name
165 * can be detected when dns_name_countlabels == 0, and is printed by
166 * dns_name_totext()/dns_name_format() as "@", consistent with RFC1035's
167 * definition of "@" as the current origin.
169 * dns_rbtnodechain_current is similar to the _first, _last, _prev and _next
170 * functions but additionally can provide the node to which the chain points.
174 * The number of level blocks to allocate at a time. Currently the maximum
175 * number of levels is allocated directly in the structure, but future
176 * revisions of this code might have a static initial block with dynamic
177 * growth. Allocating space for 256 levels when the tree is almost never that
178 * deep is wasteful, but it's not clear that it matters, since the waste is
179 * only 2MB for 1000 concurrently active chains on a system with 64-bit
182 #define DNS_RBT_LEVELBLOCK 254
184 typedef struct dns_rbtnodechain {
188 * The terminal node of the chain. It is not in levels[].
189 * This is ostensibly private ... but in a pinch it could be
190 * used tell that the chain points nowhere without needing to
191 * call dns_rbtnodechain_current().
195 * The maximum number of labels in a name is 128; bitstrings mean
196 * a conceptually very large number (which I have not bothered to
197 * compute) of logical levels because splitting can potentially occur
198 * at each bit. However, DNSSEC restricts the number of "logical"
199 * labels in a name to 255, meaning only 254 pointers are needed
202 dns_rbtnode_t * levels[DNS_RBT_LEVELBLOCK];
204 * level_count indicates how deep the chain points into the
205 * tree of trees, and is the index into the levels[] array.
206 * Thus, levels[level_count - 1] is the last level node stored.
207 * A chain that points to the top level of the tree of trees has
208 * a level_count of 0, the first level has a level_count of 1, and
211 unsigned int level_count;
213 * level_matches tells how many levels matched above the node
214 * returned by dns_rbt_findnode(). A match (partial or exact) found
215 * in the first level thus results in level_matches being set to 1.
216 * This is used by the rbtdb to set the start point for a recursive
217 * search of superdomains until the RR it is looking for is found.
219 unsigned int level_matches;
220 } dns_rbtnodechain_t;
223 ***** Public interfaces.
226 dns_rbt_create(isc_mem_t *mctx, void (*deleter)(void *, void *),
227 void *deleter_arg, dns_rbt_t **rbtp);
229 * Initialize a red-black tree of trees.
232 *\li The deleter argument, if non-null, points to a function that is
233 * responsible for cleaning up any memory associated with the data
234 * pointer of a node when the node is deleted. It is passed the
235 * deleted node's data pointer as its first argument and deleter_arg
236 * as its second argument.
239 * \li mctx is a pointer to a valid memory context.
240 *\li rbtp != NULL && *rbtp == NULL
241 *\li arg == NULL iff deleter == NULL
244 *\li If result is ISC_R_SUCCESS:
245 * *rbtp points to a valid red-black tree manager
247 *\li If result is failure:
248 * *rbtp does not point to a valid red-black tree manager.
251 *\li #ISC_R_SUCCESS Success
252 *\li #ISC_R_NOMEMORY Resource limit: Out of Memory
256 dns_rbt_addname(dns_rbt_t *rbt, dns_name_t *name, void *data);
258 * Add 'name' to the tree of trees, associated with 'data'.
261 *\li 'data' is never required to be non-NULL, but specifying it
262 * when the name is added is faster than searching for 'name'
263 * again and then setting the data pointer. The lack of a data pointer
264 * for a node also has other ramifications regarding whether
265 * dns_rbt_findname considers a node to exist, or dns_rbt_deletename
269 *\li rbt is a valid rbt manager.
270 *\li dns_name_isabsolute(name) == TRUE
273 *\li 'name' is not altered in any way.
275 *\li Any external references to nodes in the tree are unaffected by
276 * node splits that are necessary to insert the new name.
278 *\li If result is #ISC_R_SUCCESS:
279 * 'name' is findable in the red/black tree of trees in O(log N).
280 * The data pointer of the node for 'name' is set to 'data'.
282 *\li If result is #ISC_R_EXISTS or #ISC_R_NOSPACE:
283 * The tree of trees is unaltered.
285 *\li If result is #ISC_R_NOMEMORY:
289 *\li #ISC_R_SUCCESS Success
290 *\li #ISC_R_EXISTS The name already exists with associated data.
291 *\li #ISC_R_NOSPACE The name had more logical labels than are allowed.
292 *\li #ISC_R_NOMEMORY Resource Limit: Out of Memory
296 dns_rbt_addnode(dns_rbt_t *rbt, dns_name_t *name, dns_rbtnode_t **nodep);
299 * Just like dns_rbt_addname, but returns the address of the node.
302 *\li rbt is a valid rbt structure.
303 *\li dns_name_isabsolute(name) == TRUE
304 *\li nodep != NULL && *nodep == NULL
307 *\li 'name' is not altered in any way.
309 *\li Any external references to nodes in the tree are unaffected by
310 * node splits that are necessary to insert the new name.
312 *\li If result is ISC_R_SUCCESS:
313 * 'name' is findable in the red/black tree of trees in O(log N).
314 * *nodep is the node that was added for 'name'.
316 *\li If result is ISC_R_EXISTS:
317 * The tree of trees is unaltered.
318 * *nodep is the existing node for 'name'.
320 *\li If result is ISC_R_NOMEMORY:
324 *\li #ISC_R_SUCCESS Success
325 *\li #ISC_R_EXISTS The name already exists, possibly without data.
326 *\li #ISC_R_NOMEMORY Resource Limit: Out of Memory
330 dns_rbt_findname(dns_rbt_t *rbt, dns_name_t *name, unsigned int options,
331 dns_name_t *foundname, void **data);
333 * Get the data pointer associated with 'name'.
336 *\li When #DNS_RBTFIND_NOEXACT is set, the closest matching superdomain is
337 * returned (also subject to #DNS_RBTFIND_EMPTYDATA), even when there is
338 * an exact match in the tree.
340 *\li A node that has no data is considered not to exist for this function,
341 * unless the #DNS_RBTFIND_EMPTYDATA option is set.
344 *\li rbt is a valid rbt manager.
345 *\li dns_name_isabsolute(name) == TRUE
346 *\li data != NULL && *data == NULL
349 *\li 'name' and the tree are not altered in any way.
351 *\li If result is ISC_R_SUCCESS:
352 * *data is the data associated with 'name'.
354 *\li If result is DNS_R_PARTIALMATCH:
355 * *data is the data associated with the deepest superdomain
356 * of 'name' which has data.
358 *\li If result is ISC_R_NOTFOUND:
359 * Neither the name nor a superdomain was found with data.
362 *\li #ISC_R_SUCCESS Success
363 *\li #DNS_R_PARTIALMATCH Superdomain found with data
364 *\li #ISC_R_NOTFOUND No match
365 *\li #ISC_R_NOSPACE Concatenating nodes to form foundname failed
369 dns_rbt_findnode(dns_rbt_t *rbt, dns_name_t *name, dns_name_t *foundname,
370 dns_rbtnode_t **node, dns_rbtnodechain_t *chain,
371 unsigned int options, dns_rbtfindcallback_t callback,
374 * Find the node for 'name'.
377 *\li A node that has no data is considered not to exist for this function,
378 * unless the DNS_RBTFIND_EMPTYDATA option is set. This applies to both
379 * exact matches and partial matches.
381 *\li If the chain parameter is non-NULL, then the path through the tree
382 * to the DNSSEC predecessor of the searched for name is maintained,
383 * unless the DNS_RBTFIND_NOPREDECESSOR or DNS_RBTFIND_NOEXACT option
384 * is used. (For more details on those options, see below.)
386 *\li If there is no predecessor, then the chain will point to nowhere, as
387 * indicated by chain->end being NULL or dns_rbtnodechain_current
388 * returning ISC_R_NOTFOUND. Note that in a normal Internet DNS RBT
389 * there will always be a predecessor for all names except the root
390 * name, because '.' will exist and '.' is the predecessor of
391 * everything. But you can certainly construct a trivial tree and a
392 * search for it that has no predecessor.
394 *\li Within the chain structure, the 'levels' member of the structure holds
395 * the root node of each level except the first.
397 *\li The 'level_count' of the chain indicates how deep the chain to the
398 * predecessor name is, as an index into the 'levels[]' array. It does
399 * not count name elements, per se, but only levels of the tree of trees,
400 * the distinction arrising because multiple labels from a name can be
401 * stored on only one level. It is also does not include the level
402 * that has the node, since that level is not stored in levels[].
404 *\li The chain's 'level_matches' is not directly related to the predecessor.
405 * It is the number of levels above the level of the found 'node',
406 * regardless of whether it was a partial match or exact match. When
407 * the node is found in the top level tree, or no node is found at all,
408 * level_matches is 0.
410 *\li When DNS_RBTFIND_NOEXACT is set, the closest matching superdomain is
411 * returned (also subject to DNS_RBTFIND_EMPTYDATA), even when
412 * there is an exact match in the tree. In this case, the chain
413 * will not point to the DNSSEC predecessor, but will instead point
414 * to the exact match, if there was any. Thus the preceding paragraphs
415 * should have "exact match" substituted for "predecessor" to describe
416 * how the various elements of the chain are set. This was done to
417 * ensure that the chain's state was sane, and to prevent problems that
418 * occurred when running the predecessor location code under conditions
419 * it was not designed for. It is not clear *where* the chain should
420 * point when DNS_RBTFIND_NOEXACT is set, so if you end up using a chain
421 * with this option because you want a particular node, let us know
422 * where you want the chain pointed, so this can be made more firm.
425 *\li rbt is a valid rbt manager.
426 *\li dns_name_isabsolute(name) == TRUE.
427 *\li node != NULL && *node == NULL.
428 *\li #DNS_RBTFIND_NOEXACT and DNS_RBTFIND_NOPREDECESSOR are mutally
432 *\li 'name' and the tree are not altered in any way.
434 *\li If result is ISC_R_SUCCESS:
436 * *node is the terminal node for 'name'.
438 * 'foundname' and 'name' represent the same name (though not
441 * 'chain' points to the DNSSEC predecessor, if any, of 'name'.
443 * chain->level_matches and chain->level_count are equal.
446 * If result is DNS_R_PARTIALMATCH:
448 * *node is the data associated with the deepest superdomain
449 * of 'name' which has data.
451 * 'foundname' is the name of deepest superdomain (which has
452 * data, unless the DNS_RBTFIND_EMPTYDATA option is set).
454 * 'chain' points to the DNSSEC predecessor, if any, of 'name'.
457 *\li If result is ISC_R_NOTFOUND:
459 * Neither the name nor a superdomain was found. *node is NULL.
461 * 'chain' points to the DNSSEC predecessor, if any, of 'name'.
463 * chain->level_matches is 0.
467 *\li #ISC_R_SUCCESS Success
468 *\li #DNS_R_PARTIALMATCH Superdomain found with data
469 *\li #ISC_R_NOTFOUND No match, or superdomain with no data
470 *\li #ISC_R_NOSPACE Concatenating nodes to form foundname failed
474 dns_rbt_deletename(dns_rbt_t *rbt, dns_name_t *name, isc_boolean_t recurse);
476 * Delete 'name' from the tree of trees.
479 *\li When 'name' is removed, if recurse is ISC_TRUE then all of its
480 * subnames are removed too.
483 *\li rbt is a valid rbt manager.
484 *\li dns_name_isabsolute(name) == TRUE
487 *\li 'name' is not altered in any way.
489 *\li Does NOT ensure that any external references to nodes in the tree
490 * are unaffected by node joins.
492 *\li If result is ISC_R_SUCCESS:
493 * 'name' does not appear in the tree with data; however,
494 * the node for the name might still exist which can be
495 * found with dns_rbt_findnode (but not dns_rbt_findname).
497 *\li If result is ISC_R_NOTFOUND:
498 * 'name' does not appear in the tree with data, because
499 * it did not appear in the tree before the function was called.
501 *\li If result is something else:
502 * See result codes for dns_rbt_findnode (if it fails, the
503 * node is not deleted) or dns_rbt_deletenode (if it fails,
504 * the node is deleted, but the tree is not optimized when
505 * it could have been).
508 *\li #ISC_R_SUCCESS Success
509 *\li #ISC_R_NOTFOUND No match
510 *\li something_else Any return code from dns_rbt_findnode except
511 * DNS_R_PARTIALMATCH (which causes ISC_R_NOTFOUND
512 * to be returned instead), and any code from
513 * dns_rbt_deletenode.
517 dns_rbt_deletenode(dns_rbt_t *rbt, dns_rbtnode_t *node, isc_boolean_t recurse);
519 * Delete 'node' from the tree of trees.
522 *\li When 'node' is removed, if recurse is ISC_TRUE then all nodes
523 * in levels down from it are removed too.
526 *\li rbt is a valid rbt manager.
530 *\li Does NOT ensure that any external references to nodes in the tree
531 * are unaffected by node joins.
533 *\li If result is ISC_R_SUCCESS:
534 * 'node' does not appear in the tree with data; however,
535 * the node might still exist if it serves as a pointer to
536 * a lower tree level as long as 'recurse' was false, hence
537 * the node could can be found with dns_rbt_findnode whem
538 * that function's empty_data_ok parameter is true.
540 *\li If result is ISC_R_NOMEMORY or ISC_R_NOSPACE:
541 * The node was deleted, but the tree structure was not
545 *\li #ISC_R_SUCCESS Success
546 *\li #ISC_R_NOMEMORY Resource Limit: Out of Memory when joining nodes.
547 *\li #ISC_R_NOSPACE dns_name_concatenate failed when joining nodes.
551 dns_rbt_namefromnode(dns_rbtnode_t *node, dns_name_t *name);
553 * Convert the sequence of labels stored at 'node' into a 'name'.
556 *\li This function does not return the full name, from the root, but
557 * just the labels at the indicated node.
559 *\li The name data pointed to by 'name' is the information stored
560 * in the node, not a copy. Altering the data at this pointer
561 * will likely cause grief.
564 * \li name->offsets == NULL
567 * \li 'name' is DNS_NAMEATTR_READONLY.
569 * \li 'name' will point directly to the labels stored after the
570 * dns_rbtnode_t struct.
572 * \li 'name' will have offsets that also point to the information stored
573 * as part of the node.
577 dns_rbt_fullnamefromnode(dns_rbtnode_t *node, dns_name_t *name);
579 * Like dns_rbt_namefromnode, but returns the full name from the root.
582 * \li Unlike dns_rbt_namefromnode, the name will not point directly
583 * to node data. Rather, dns_name_concatenate will be used to copy
584 * the name data from each node into the 'name' argument.
588 * \li name has a dedicated buffer.
592 * \li ISC_R_NOSPACE (possible via dns_name_concatenate)
593 * \li DNS_R_NAMETOOLONG (possible via dns_name_concatenate)
597 dns_rbt_formatnodename(dns_rbtnode_t *node, char *printname,
600 * Format the full name of a node for printing, using dns_name_format().
603 * \li 'size' is the length of the printname buffer. This should be
604 * DNS_NAME_FORMATSIZE or larger.
607 * \li node and printname are not NULL.
610 * \li The 'printname' pointer.
614 dns_rbt_nodecount(dns_rbt_t *rbt);
616 * Obtain the number of nodes in the tree of trees.
619 * \li rbt is a valid rbt manager.
623 dns_rbt_destroy(dns_rbt_t **rbtp);
625 dns_rbt_destroy2(dns_rbt_t **rbtp, unsigned int quantum);
627 * Stop working with a red-black tree of trees.
628 * If 'quantum' is zero then the entire tree will be destroyed.
629 * If 'quantum' is non zero then up to 'quantum' nodes will be destroyed
630 * allowing the rbt to be incrementally destroyed by repeated calls to
631 * dns_rbt_destroy2(). Once dns_rbt_destroy2() has been called no other
632 * operations than dns_rbt_destroy()/dns_rbt_destroy2() should be
633 * performed on the tree of trees.
636 * \li *rbt is a valid rbt manager.
638 * Ensures on ISC_R_SUCCESS:
639 * \li All space allocated by the RBT library has been returned.
641 * \li *rbt is invalidated as an rbt manager.
645 * \li ISC_R_QUOTA if 'quantum' nodes have been destroyed.
649 dns_rbt_printall(dns_rbt_t *rbt);
651 * Print an ASCII representation of the internal structure of the red-black
655 * \li The name stored at each node, along with the node's color, is printed.
656 * Then the down pointer, left and right pointers are displayed
657 * recursively in turn. NULL down pointers are silently omitted;
658 * NULL left and right pointers are printed.
662 ***** Chain Functions
666 dns_rbtnodechain_init(dns_rbtnodechain_t *chain, isc_mem_t *mctx);
668 * Initialize 'chain'.
671 *\li 'chain' is a valid pointer.
673 *\li 'mctx' is a valid memory context.
676 *\li 'chain' is suitable for use.
680 dns_rbtnodechain_reset(dns_rbtnodechain_t *chain);
682 * Free any dynamic storage associated with 'chain', and then reinitialize
686 *\li 'chain' is a valid pointer.
689 *\li 'chain' is suitable for use, and uses no dynamic storage.
693 dns_rbtnodechain_invalidate(dns_rbtnodechain_t *chain);
695 * Free any dynamic storage associated with 'chain', and then invalidates it.
698 *\li Future calls to any dns_rbtnodechain_ function will need to call
699 * dns_rbtnodechain_init on the chain first (except, of course,
700 * dns_rbtnodechain_init itself).
703 *\li 'chain' is a valid chain.
706 *\li 'chain' is no longer suitable for use, and uses no dynamic storage.
710 dns_rbtnodechain_current(dns_rbtnodechain_t *chain, dns_name_t *name,
711 dns_name_t *origin, dns_rbtnode_t **node);
713 * Provide the name, origin and node to which the chain is currently pointed.
716 *\li The tree need not have be locked against additions for the chain
717 * to remain valid, however there are no guarantees if any deletion
718 * has been made since the chain was established.
721 *\li 'chain' is a valid chain.
724 *\li 'node', if non-NULL, is the node to which the chain was pointed
725 * by dns_rbt_findnode, dns_rbtnodechain_first or dns_rbtnodechain_last.
726 * If none were called for the chain since it was initialized or reset,
727 * or if the was no predecessor to the name searched for with
728 * dns_rbt_findnode, then '*node' is NULL and ISC_R_NOTFOUND is returned.
730 *\li 'name', if non-NULL, is the name stored at the terminal level of
731 * the chain. This is typically a single label, like the "www" of
732 * "www.isc.org", but need not be so. At the root of the tree of trees,
733 * if the node is "." then 'name' is ".", otherwise it is relative to ".".
734 * (Minimalist and atypical case: if the tree has just the name
735 * "isc.org." then the root node's stored name is "isc.org." but 'name'
736 * will be "isc.org".)
738 *\li 'origin', if non-NULL, is the sequence of labels in the levels
739 * above the terminal level, such as "isc.org." in the above example.
740 * 'origin' is always "." for the root node.
744 *\li #ISC_R_SUCCESS name, origin & node were successfully set.
745 *\li #ISC_R_NOTFOUND The chain does not point to any node.
746 *\li <something_else> Any error return from dns_name_concatenate.
750 dns_rbtnodechain_first(dns_rbtnodechain_t *chain, dns_rbt_t *rbt,
751 dns_name_t *name, dns_name_t *origin);
753 * Set the chain to the lexically first node in the tree of trees.
756 *\li By the definition of ordering for DNS names, the root of the tree of
757 * trees is the very first node, since everything else in the megatree
758 * uses it as a common suffix.
761 *\li 'chain' is a valid chain.
762 *\li 'rbt' is a valid rbt manager.
765 *\li The chain points to the very first node of the tree.
767 *\li 'name' and 'origin', if non-NULL, are set as described for
768 * dns_rbtnodechain_current. Thus 'origin' will always be ".".
771 *\li #DNS_R_NEWORIGIN The name & origin were successfully set.
772 *\li <something_else> Any error result from dns_rbtnodechain_current.
776 dns_rbtnodechain_last(dns_rbtnodechain_t *chain, dns_rbt_t *rbt,
777 dns_name_t *name, dns_name_t *origin);
779 * Set the chain to the lexically last node in the tree of trees.
782 *\li 'chain' is a valid chain.
783 *\li 'rbt' is a valid rbt manager.
786 *\li The chain points to the very last node of the tree.
788 *\li 'name' and 'origin', if non-NULL, are set as described for
789 * dns_rbtnodechain_current.
792 *\li #DNS_R_NEWORIGIN The name & origin were successfully set.
793 *\li #ISC_R_NOMEMORY Resource Limit: Out of Memory building chain.
794 *\li <something_else> Any error result from dns_name_concatenate.
798 dns_rbtnodechain_prev(dns_rbtnodechain_t *chain, dns_name_t *name,
801 * Adjusts chain to point the DNSSEC predecessor of the name to which it
802 * is currently pointed.
805 *\li 'chain' is a valid chain.
806 *\li 'chain' has been pointed somewhere in the tree with dns_rbt_findnode,
807 * dns_rbtnodechain_first or dns_rbtnodechain_last -- and remember that
808 * dns_rbt_findnode is not guaranteed to point the chain somewhere,
809 * since there may have been no predecessor to the searched for name.
812 *\li The chain is pointed to the predecessor of its current target.
814 *\li 'name' and 'origin', if non-NULL, are set as described for
815 * dns_rbtnodechain_current.
817 *\li 'origin' is only if a new origin was found.
820 *\li #ISC_R_SUCCESS The predecessor was found and 'name' was set.
821 *\li #DNS_R_NEWORIGIN The predecessor was found with a different
822 * origin and 'name' and 'origin' were set.
823 *\li #ISC_R_NOMORE There was no predecessor.
824 *\li <something_else> Any error result from dns_rbtnodechain_current.
828 dns_rbtnodechain_next(dns_rbtnodechain_t *chain, dns_name_t *name,
831 * Adjusts chain to point the DNSSEC successor of the name to which it
832 * is currently pointed.
835 *\li 'chain' is a valid chain.
836 *\li 'chain' has been pointed somewhere in the tree with dns_rbt_findnode,
837 * dns_rbtnodechain_first or dns_rbtnodechain_last -- and remember that
838 * dns_rbt_findnode is not guaranteed to point the chain somewhere,
839 * since there may have been no predecessor to the searched for name.
842 *\li The chain is pointed to the successor of its current target.
844 *\li 'name' and 'origin', if non-NULL, are set as described for
845 * dns_rbtnodechain_current.
847 *\li 'origin' is only if a new origin was found.
850 *\li #ISC_R_SUCCESS The successor was found and 'name' was set.
851 *\li #DNS_R_NEWORIGIN The successor was found with a different
852 * origin and 'name' and 'origin' were set.
853 *\li #ISC_R_NOMORE There was no successor.
854 *\li <something_else> Any error result from dns_name_concatenate.
858 * Wrapper macros for manipulating the rbtnode reference counter:
859 * Since we selectively use isc_refcount_t for the reference counter of
860 * a rbtnode, operations on the counter depend on the actual type of it.
861 * The following macros provide a common interface to these operations,
862 * hiding the back-end. The usage is the same as that of isc_refcount_xxx().
864 #ifdef DNS_RBT_USEISCREFCOUNT
865 #define dns_rbtnode_refinit(node, n) \
867 isc_refcount_init(&(node)->references, (n)); \
869 #define dns_rbtnode_refdestroy(node) \
871 isc_refcount_destroy(&(node)->references); \
873 #define dns_rbtnode_refcurrent(node) \
874 isc_refcount_current(&(node)->references)
875 #define dns_rbtnode_refincrement0(node, refs) \
877 isc_refcount_increment0(&(node)->references, (refs)); \
879 #define dns_rbtnode_refincrement(node, refs) \
881 isc_refcount_increment(&(node)->references, (refs)); \
883 #define dns_rbtnode_refdecrement(node, refs) \
885 isc_refcount_decrement(&(node)->references, (refs)); \
887 #else /* DNS_RBT_USEISCREFCOUNT */
888 #define dns_rbtnode_refinit(node, n) ((node)->references = (n))
889 #define dns_rbtnode_refdestroy(node) (REQUIRE((node)->references == 0))
890 #define dns_rbtnode_refcurrent(node) ((node)->references)
891 #define dns_rbtnode_refincrement0(node, refs) \
893 unsigned int *_tmp = (unsigned int *)(refs); \
894 (node)->references++; \
895 if ((_tmp) != NULL) \
896 (*_tmp) = (node)->references; \
898 #define dns_rbtnode_refincrement(node, refs) \
900 REQUIRE((node)->references > 0); \
901 (node)->references++; \
902 if ((refs) != NULL) \
903 (*refs) = (node)->references; \
905 #define dns_rbtnode_refdecrement(node, refs) \
907 REQUIRE((node)->references > 0); \
908 (node)->references--; \
909 if ((refs) != NULL) \
910 (*refs) = (node)->references; \
912 #endif /* DNS_RBT_USEISCREFCOUNT */
916 #endif /* DNS_RBT_H */