2 * Copyright (C) 2004-2007, 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 1.69.36.2 2009/01/19 23:47:03 tbox 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;
77 dns_rbtnode_t *parent;
81 #ifdef DNS_RBT_USEHASH
82 dns_rbtnode_t *hashnext;
86 * Used for LRU cache. This linked list is used to mark nodes which
87 * have no data any longer, but we cannot unlink at that exact moment
88 * because we did not or could not obtain a write lock on the tree.
90 ISC_LINK(dns_rbtnode_t) deadlink;
94 * The following bitfields add up to a total bitwidth of 32.
95 * The range of values necessary for each item is indicated,
96 * but in the case of "attributes" the field is wider to accommodate
97 * possible future expansion. "offsetlen" could be one bit
98 * narrower by always adjusting its value by 1 to find the real
99 * offsetlen, but doing so does not gain anything (except perhaps
100 * another bit for "attributes", which doesn't yet need any more).
102 * In each case below the "range" indicated is what's _necessary_ for
103 * the bitfield to hold, not what it actually _can_ hold.
105 unsigned int is_root : 1; /*%< range is 0..1 */
106 unsigned int color : 1; /*%< range is 0..1 */
107 unsigned int find_callback : 1; /*%< range is 0..1 */
108 unsigned int attributes : 4; /*%< range is 0..2 */
109 unsigned int namelen : 8; /*%< range is 1..255 */
110 unsigned int offsetlen : 8; /*%< range is 1..128 */
111 unsigned int padbytes : 9; /*%< range is 0..380 */
114 #ifdef DNS_RBT_USEHASH
115 unsigned int hashval;
120 * These values are used in the RBT DB implementation. The appropriate
121 * node lock must be held before accessing them.
124 unsigned int dirty:1;
126 unsigned int locknum:DNS_RBT_LOCKLENGTH;
127 #ifndef DNS_RBT_USEISCREFCOUNT
128 unsigned int references:DNS_RBT_REFLENGTH;
130 isc_refcount_t references; /* note that this is not in the bitfield */
135 typedef isc_result_t (*dns_rbtfindcallback_t)(dns_rbtnode_t *node,
144 * A chain is used to keep track of the sequence of nodes to reach any given
145 * node from the root of the tree. Originally nodes did not have parent
146 * pointers in them (for memory usage reasons) so there was no way to find
147 * the path back to the root from any given node. Now that nodes have parent
148 * pointers, chains might be going away in a future release, though the
149 * movement functionality would remain.
151 * In any event, parent information, whether via parent pointers or chains, is
152 * necessary information for iterating through the tree or for basic internal
153 * tree maintenance issues (ie, the rotations that are done to rebalance the
154 * tree when a node is added). The obvious implication of this is that for a
155 * chain to remain valid, the tree has to be locked down against writes for the
156 * duration of the useful life of the chain, because additions or removals can
157 * change the path from the root to the node the chain has targeted.
159 * The dns_rbtnodechain_ functions _first, _last, _prev and _next all take
160 * dns_name_t parameters for the name and the origin, which can be NULL. If
161 * non-NULL, 'name' will end up pointing to the name data and offsets that are
162 * stored at the node (and thus it will be read-only), so it should be a
163 * regular dns_name_t that has been initialized with dns_name_init. When
164 * 'origin' is non-NULL, it will get the name of the origin stored in it, so it
165 * needs to have its own buffer space and offsets, which is most easily
166 * accomplished with a dns_fixedname_t. It is _not_ necessary to reinitialize
167 * either 'name' or 'origin' between calls to the chain functions.
169 * NOTE WELL: even though the name data at the root of the tree of trees will
170 * be absolute (typically just "."), it will will be made into a relative name
171 * with an origin of "." -- an empty name when the node is ".". This is
172 * because a common on operation on 'name' and 'origin' is to use
173 * dns_name_concatenate() on them to generate the complete name. An empty name
174 * can be detected when dns_name_countlabels == 0, and is printed by
175 * dns_name_totext()/dns_name_format() as "@", consistent with RFC1035's
176 * definition of "@" as the current origin.
178 * dns_rbtnodechain_current is similar to the _first, _last, _prev and _next
179 * functions but additionally can provide the node to which the chain points.
183 * The number of level blocks to allocate at a time. Currently the maximum
184 * number of levels is allocated directly in the structure, but future
185 * revisions of this code might have a static initial block with dynamic
186 * growth. Allocating space for 256 levels when the tree is almost never that
187 * deep is wasteful, but it's not clear that it matters, since the waste is
188 * only 2MB for 1000 concurrently active chains on a system with 64-bit
191 #define DNS_RBT_LEVELBLOCK 254
193 typedef struct dns_rbtnodechain {
197 * The terminal node of the chain. It is not in levels[].
198 * This is ostensibly private ... but in a pinch it could be
199 * used tell that the chain points nowhere without needing to
200 * call dns_rbtnodechain_current().
204 * The maximum number of labels in a name is 128; bitstrings mean
205 * a conceptually very large number (which I have not bothered to
206 * compute) of logical levels because splitting can potentially occur
207 * at each bit. However, DNSSEC restricts the number of "logical"
208 * labels in a name to 255, meaning only 254 pointers are needed
211 dns_rbtnode_t * levels[DNS_RBT_LEVELBLOCK];
213 * level_count indicates how deep the chain points into the
214 * tree of trees, and is the index into the levels[] array.
215 * Thus, levels[level_count - 1] is the last level node stored.
216 * A chain that points to the top level of the tree of trees has
217 * a level_count of 0, the first level has a level_count of 1, and
220 unsigned int level_count;
222 * level_matches tells how many levels matched above the node
223 * returned by dns_rbt_findnode(). A match (partial or exact) found
224 * in the first level thus results in level_matches being set to 1.
225 * This is used by the rbtdb to set the start point for a recursive
226 * search of superdomains until the RR it is looking for is found.
228 unsigned int level_matches;
229 } dns_rbtnodechain_t;
232 ***** Public interfaces.
235 dns_rbt_create(isc_mem_t *mctx, void (*deleter)(void *, void *),
236 void *deleter_arg, dns_rbt_t **rbtp);
238 * Initialize a red-black tree of trees.
241 *\li The deleter argument, if non-null, points to a function that is
242 * responsible for cleaning up any memory associated with the data
243 * pointer of a node when the node is deleted. It is passed the
244 * deleted node's data pointer as its first argument and deleter_arg
245 * as its second argument.
248 * \li mctx is a pointer to a valid memory context.
249 *\li rbtp != NULL && *rbtp == NULL
250 *\li arg == NULL iff deleter == NULL
253 *\li If result is ISC_R_SUCCESS:
254 * *rbtp points to a valid red-black tree manager
256 *\li If result is failure:
257 * *rbtp does not point to a valid red-black tree manager.
260 *\li #ISC_R_SUCCESS Success
261 *\li #ISC_R_NOMEMORY Resource limit: Out of Memory
265 dns_rbt_addname(dns_rbt_t *rbt, dns_name_t *name, void *data);
267 * Add 'name' to the tree of trees, associated with 'data'.
270 *\li 'data' is never required to be non-NULL, but specifying it
271 * when the name is added is faster than searching for 'name'
272 * again and then setting the data pointer. The lack of a data pointer
273 * for a node also has other ramifications regarding whether
274 * dns_rbt_findname considers a node to exist, or dns_rbt_deletename
278 *\li rbt is a valid rbt manager.
279 *\li dns_name_isabsolute(name) == TRUE
282 *\li 'name' is not altered in any way.
284 *\li Any external references to nodes in the tree are unaffected by
285 * node splits that are necessary to insert the new name.
287 *\li If result is #ISC_R_SUCCESS:
288 * 'name' is findable in the red/black tree of trees in O(log N).
289 * The data pointer of the node for 'name' is set to 'data'.
291 *\li If result is #ISC_R_EXISTS or #ISC_R_NOSPACE:
292 * The tree of trees is unaltered.
294 *\li If result is #ISC_R_NOMEMORY:
298 *\li #ISC_R_SUCCESS Success
299 *\li #ISC_R_EXISTS The name already exists with associated data.
300 *\li #ISC_R_NOSPACE The name had more logical labels than are allowed.
301 *\li #ISC_R_NOMEMORY Resource Limit: Out of Memory
305 dns_rbt_addnode(dns_rbt_t *rbt, dns_name_t *name, dns_rbtnode_t **nodep);
308 * Just like dns_rbt_addname, but returns the address of the node.
311 *\li rbt is a valid rbt structure.
312 *\li dns_name_isabsolute(name) == TRUE
313 *\li nodep != NULL && *nodep == NULL
316 *\li 'name' is not altered in any way.
318 *\li Any external references to nodes in the tree are unaffected by
319 * node splits that are necessary to insert the new name.
321 *\li If result is ISC_R_SUCCESS:
322 * 'name' is findable in the red/black tree of trees in O(log N).
323 * *nodep is the node that was added for 'name'.
325 *\li If result is ISC_R_EXISTS:
326 * The tree of trees is unaltered.
327 * *nodep is the existing node for 'name'.
329 *\li If result is ISC_R_NOMEMORY:
333 *\li #ISC_R_SUCCESS Success
334 *\li #ISC_R_EXISTS The name already exists, possibly without data.
335 *\li #ISC_R_NOMEMORY Resource Limit: Out of Memory
339 dns_rbt_findname(dns_rbt_t *rbt, dns_name_t *name, unsigned int options,
340 dns_name_t *foundname, void **data);
342 * Get the data pointer associated with 'name'.
345 *\li When #DNS_RBTFIND_NOEXACT is set, the closest matching superdomain is
346 * returned (also subject to #DNS_RBTFIND_EMPTYDATA), even when there is
347 * an exact match in the tree.
349 *\li A node that has no data is considered not to exist for this function,
350 * unless the #DNS_RBTFIND_EMPTYDATA option is set.
353 *\li rbt is a valid rbt manager.
354 *\li dns_name_isabsolute(name) == TRUE
355 *\li data != NULL && *data == NULL
358 *\li 'name' and the tree are not altered in any way.
360 *\li If result is ISC_R_SUCCESS:
361 * *data is the data associated with 'name'.
363 *\li If result is DNS_R_PARTIALMATCH:
364 * *data is the data associated with the deepest superdomain
365 * of 'name' which has data.
367 *\li If result is ISC_R_NOTFOUND:
368 * Neither the name nor a superdomain was found with data.
371 *\li #ISC_R_SUCCESS Success
372 *\li #DNS_R_PARTIALMATCH Superdomain found with data
373 *\li #ISC_R_NOTFOUND No match
374 *\li #ISC_R_NOSPACE Concatenating nodes to form foundname failed
378 dns_rbt_findnode(dns_rbt_t *rbt, dns_name_t *name, dns_name_t *foundname,
379 dns_rbtnode_t **node, dns_rbtnodechain_t *chain,
380 unsigned int options, dns_rbtfindcallback_t callback,
383 * Find the node for 'name'.
386 *\li A node that has no data is considered not to exist for this function,
387 * unless the DNS_RBTFIND_EMPTYDATA option is set. This applies to both
388 * exact matches and partial matches.
390 *\li If the chain parameter is non-NULL, then the path through the tree
391 * to the DNSSEC predecessor of the searched for name is maintained,
392 * unless the DNS_RBTFIND_NOPREDECESSOR or DNS_RBTFIND_NOEXACT option
393 * is used. (For more details on those options, see below.)
395 *\li If there is no predecessor, then the chain will point to nowhere, as
396 * indicated by chain->end being NULL or dns_rbtnodechain_current
397 * returning ISC_R_NOTFOUND. Note that in a normal Internet DNS RBT
398 * there will always be a predecessor for all names except the root
399 * name, because '.' will exist and '.' is the predecessor of
400 * everything. But you can certainly construct a trivial tree and a
401 * search for it that has no predecessor.
403 *\li Within the chain structure, the 'levels' member of the structure holds
404 * the root node of each level except the first.
406 *\li The 'level_count' of the chain indicates how deep the chain to the
407 * predecessor name is, as an index into the 'levels[]' array. It does
408 * not count name elements, per se, but only levels of the tree of trees,
409 * the distinction arising because multiple labels from a name can be
410 * stored on only one level. It is also does not include the level
411 * that has the node, since that level is not stored in levels[].
413 *\li The chain's 'level_matches' is not directly related to the predecessor.
414 * It is the number of levels above the level of the found 'node',
415 * regardless of whether it was a partial match or exact match. When
416 * the node is found in the top level tree, or no node is found at all,
417 * level_matches is 0.
419 *\li When DNS_RBTFIND_NOEXACT is set, the closest matching superdomain is
420 * returned (also subject to DNS_RBTFIND_EMPTYDATA), even when
421 * there is an exact match in the tree. In this case, the chain
422 * will not point to the DNSSEC predecessor, but will instead point
423 * to the exact match, if there was any. Thus the preceding paragraphs
424 * should have "exact match" substituted for "predecessor" to describe
425 * how the various elements of the chain are set. This was done to
426 * ensure that the chain's state was sane, and to prevent problems that
427 * occurred when running the predecessor location code under conditions
428 * it was not designed for. It is not clear *where* the chain should
429 * point when DNS_RBTFIND_NOEXACT is set, so if you end up using a chain
430 * with this option because you want a particular node, let us know
431 * where you want the chain pointed, so this can be made more firm.
434 *\li rbt is a valid rbt manager.
435 *\li dns_name_isabsolute(name) == TRUE.
436 *\li node != NULL && *node == NULL.
437 *\li #DNS_RBTFIND_NOEXACT and DNS_RBTFIND_NOPREDECESSOR are mutually
441 *\li 'name' and the tree are not altered in any way.
443 *\li If result is ISC_R_SUCCESS:
445 * *node is the terminal node for 'name'.
447 * 'foundname' and 'name' represent the same name (though not
450 * 'chain' points to the DNSSEC predecessor, if any, of 'name'.
452 * chain->level_matches and chain->level_count are equal.
455 * If result is DNS_R_PARTIALMATCH:
457 * *node is the data associated with the deepest superdomain
458 * of 'name' which has data.
460 * 'foundname' is the name of deepest superdomain (which has
461 * data, unless the DNS_RBTFIND_EMPTYDATA option is set).
463 * 'chain' points to the DNSSEC predecessor, if any, of 'name'.
466 *\li If result is ISC_R_NOTFOUND:
468 * Neither the name nor a superdomain was found. *node is NULL.
470 * 'chain' points to the DNSSEC predecessor, if any, of 'name'.
472 * chain->level_matches is 0.
476 *\li #ISC_R_SUCCESS Success
477 *\li #DNS_R_PARTIALMATCH Superdomain found with data
478 *\li #ISC_R_NOTFOUND No match, or superdomain with no data
479 *\li #ISC_R_NOSPACE Concatenating nodes to form foundname failed
483 dns_rbt_deletename(dns_rbt_t *rbt, dns_name_t *name, isc_boolean_t recurse);
485 * Delete 'name' from the tree of trees.
488 *\li When 'name' is removed, if recurse is ISC_TRUE then all of its
489 * subnames are removed too.
492 *\li rbt is a valid rbt manager.
493 *\li dns_name_isabsolute(name) == TRUE
496 *\li 'name' is not altered in any way.
498 *\li Does NOT ensure that any external references to nodes in the tree
499 * are unaffected by node joins.
501 *\li If result is ISC_R_SUCCESS:
502 * 'name' does not appear in the tree with data; however,
503 * the node for the name might still exist which can be
504 * found with dns_rbt_findnode (but not dns_rbt_findname).
506 *\li If result is ISC_R_NOTFOUND:
507 * 'name' does not appear in the tree with data, because
508 * it did not appear in the tree before the function was called.
510 *\li If result is something else:
511 * See result codes for dns_rbt_findnode (if it fails, the
512 * node is not deleted) or dns_rbt_deletenode (if it fails,
513 * the node is deleted, but the tree is not optimized when
514 * it could have been).
517 *\li #ISC_R_SUCCESS Success
518 *\li #ISC_R_NOTFOUND No match
519 *\li something_else Any return code from dns_rbt_findnode except
520 * DNS_R_PARTIALMATCH (which causes ISC_R_NOTFOUND
521 * to be returned instead), and any code from
522 * dns_rbt_deletenode.
526 dns_rbt_deletenode(dns_rbt_t *rbt, dns_rbtnode_t *node, isc_boolean_t recurse);
528 * Delete 'node' from the tree of trees.
531 *\li When 'node' is removed, if recurse is ISC_TRUE then all nodes
532 * in levels down from it are removed too.
535 *\li rbt is a valid rbt manager.
539 *\li Does NOT ensure that any external references to nodes in the tree
540 * are unaffected by node joins.
542 *\li If result is ISC_R_SUCCESS:
543 * 'node' does not appear in the tree with data; however,
544 * the node might still exist if it serves as a pointer to
545 * a lower tree level as long as 'recurse' was false, hence
546 * the node could can be found with dns_rbt_findnode when
547 * that function's empty_data_ok parameter is true.
549 *\li If result is ISC_R_NOMEMORY or ISC_R_NOSPACE:
550 * The node was deleted, but the tree structure was not
554 *\li #ISC_R_SUCCESS Success
555 *\li #ISC_R_NOMEMORY Resource Limit: Out of Memory when joining nodes.
556 *\li #ISC_R_NOSPACE dns_name_concatenate failed when joining nodes.
560 dns_rbt_namefromnode(dns_rbtnode_t *node, dns_name_t *name);
562 * Convert the sequence of labels stored at 'node' into a 'name'.
565 *\li This function does not return the full name, from the root, but
566 * just the labels at the indicated node.
568 *\li The name data pointed to by 'name' is the information stored
569 * in the node, not a copy. Altering the data at this pointer
570 * will likely cause grief.
573 * \li name->offsets == NULL
576 * \li 'name' is DNS_NAMEATTR_READONLY.
578 * \li 'name' will point directly to the labels stored after the
579 * dns_rbtnode_t struct.
581 * \li 'name' will have offsets that also point to the information stored
582 * as part of the node.
586 dns_rbt_fullnamefromnode(dns_rbtnode_t *node, dns_name_t *name);
588 * Like dns_rbt_namefromnode, but returns the full name from the root.
591 * \li Unlike dns_rbt_namefromnode, the name will not point directly
592 * to node data. Rather, dns_name_concatenate will be used to copy
593 * the name data from each node into the 'name' argument.
597 * \li name has a dedicated buffer.
601 * \li ISC_R_NOSPACE (possible via dns_name_concatenate)
602 * \li DNS_R_NAMETOOLONG (possible via dns_name_concatenate)
606 dns_rbt_formatnodename(dns_rbtnode_t *node, char *printname,
609 * Format the full name of a node for printing, using dns_name_format().
612 * \li 'size' is the length of the printname buffer. This should be
613 * DNS_NAME_FORMATSIZE or larger.
616 * \li node and printname are not NULL.
619 * \li The 'printname' pointer.
623 dns_rbt_nodecount(dns_rbt_t *rbt);
625 * Obtain the number of nodes in the tree of trees.
628 * \li rbt is a valid rbt manager.
632 dns_rbt_destroy(dns_rbt_t **rbtp);
634 dns_rbt_destroy2(dns_rbt_t **rbtp, unsigned int quantum);
636 * Stop working with a red-black tree of trees.
637 * If 'quantum' is zero then the entire tree will be destroyed.
638 * If 'quantum' is non zero then up to 'quantum' nodes will be destroyed
639 * allowing the rbt to be incrementally destroyed by repeated calls to
640 * dns_rbt_destroy2(). Once dns_rbt_destroy2() has been called no other
641 * operations than dns_rbt_destroy()/dns_rbt_destroy2() should be
642 * performed on the tree of trees.
645 * \li *rbt is a valid rbt manager.
647 * Ensures on ISC_R_SUCCESS:
648 * \li All space allocated by the RBT library has been returned.
650 * \li *rbt is invalidated as an rbt manager.
654 * \li ISC_R_QUOTA if 'quantum' nodes have been destroyed.
658 dns_rbt_printall(dns_rbt_t *rbt);
660 * Print an ASCII representation of the internal structure of the red-black
664 * \li The name stored at each node, along with the node's color, is printed.
665 * Then the down pointer, left and right pointers are displayed
666 * recursively in turn. NULL down pointers are silently omitted;
667 * NULL left and right pointers are printed.
671 ***** Chain Functions
675 dns_rbtnodechain_init(dns_rbtnodechain_t *chain, isc_mem_t *mctx);
677 * Initialize 'chain'.
680 *\li 'chain' is a valid pointer.
682 *\li 'mctx' is a valid memory context.
685 *\li 'chain' is suitable for use.
689 dns_rbtnodechain_reset(dns_rbtnodechain_t *chain);
691 * Free any dynamic storage associated with 'chain', and then reinitialize
695 *\li 'chain' is a valid pointer.
698 *\li 'chain' is suitable for use, and uses no dynamic storage.
702 dns_rbtnodechain_invalidate(dns_rbtnodechain_t *chain);
704 * Free any dynamic storage associated with 'chain', and then invalidates it.
707 *\li Future calls to any dns_rbtnodechain_ function will need to call
708 * dns_rbtnodechain_init on the chain first (except, of course,
709 * dns_rbtnodechain_init itself).
712 *\li 'chain' is a valid chain.
715 *\li 'chain' is no longer suitable for use, and uses no dynamic storage.
719 dns_rbtnodechain_current(dns_rbtnodechain_t *chain, dns_name_t *name,
720 dns_name_t *origin, dns_rbtnode_t **node);
722 * Provide the name, origin and node to which the chain is currently pointed.
725 *\li The tree need not have be locked against additions for the chain
726 * to remain valid, however there are no guarantees if any deletion
727 * has been made since the chain was established.
730 *\li 'chain' is a valid chain.
733 *\li 'node', if non-NULL, is the node to which the chain was pointed
734 * by dns_rbt_findnode, dns_rbtnodechain_first or dns_rbtnodechain_last.
735 * If none were called for the chain since it was initialized or reset,
736 * or if the was no predecessor to the name searched for with
737 * dns_rbt_findnode, then '*node' is NULL and ISC_R_NOTFOUND is returned.
739 *\li 'name', if non-NULL, is the name stored at the terminal level of
740 * the chain. This is typically a single label, like the "www" of
741 * "www.isc.org", but need not be so. At the root of the tree of trees,
742 * if the node is "." then 'name' is ".", otherwise it is relative to ".".
743 * (Minimalist and atypical case: if the tree has just the name
744 * "isc.org." then the root node's stored name is "isc.org." but 'name'
745 * will be "isc.org".)
747 *\li 'origin', if non-NULL, is the sequence of labels in the levels
748 * above the terminal level, such as "isc.org." in the above example.
749 * 'origin' is always "." for the root node.
753 *\li #ISC_R_SUCCESS name, origin & node were successfully set.
754 *\li #ISC_R_NOTFOUND The chain does not point to any node.
755 *\li <something_else> Any error return from dns_name_concatenate.
759 dns_rbtnodechain_first(dns_rbtnodechain_t *chain, dns_rbt_t *rbt,
760 dns_name_t *name, dns_name_t *origin);
762 * Set the chain to the lexically first node in the tree of trees.
765 *\li By the definition of ordering for DNS names, the root of the tree of
766 * trees is the very first node, since everything else in the megatree
767 * uses it as a common suffix.
770 *\li 'chain' is a valid chain.
771 *\li 'rbt' is a valid rbt manager.
774 *\li The chain points to the very first node of the tree.
776 *\li 'name' and 'origin', if non-NULL, are set as described for
777 * dns_rbtnodechain_current. Thus 'origin' will always be ".".
780 *\li #DNS_R_NEWORIGIN The name & origin were successfully set.
781 *\li <something_else> Any error result from dns_rbtnodechain_current.
785 dns_rbtnodechain_last(dns_rbtnodechain_t *chain, dns_rbt_t *rbt,
786 dns_name_t *name, dns_name_t *origin);
788 * Set the chain to the lexically last node in the tree of trees.
791 *\li 'chain' is a valid chain.
792 *\li 'rbt' is a valid rbt manager.
795 *\li The chain points to the very last node of the tree.
797 *\li 'name' and 'origin', if non-NULL, are set as described for
798 * dns_rbtnodechain_current.
801 *\li #DNS_R_NEWORIGIN The name & origin were successfully set.
802 *\li #ISC_R_NOMEMORY Resource Limit: Out of Memory building chain.
803 *\li <something_else> Any error result from dns_name_concatenate.
807 dns_rbtnodechain_prev(dns_rbtnodechain_t *chain, dns_name_t *name,
810 * Adjusts chain to point the DNSSEC predecessor of the name to which it
811 * is currently pointed.
814 *\li 'chain' is a valid chain.
815 *\li 'chain' has been pointed somewhere in the tree with dns_rbt_findnode,
816 * dns_rbtnodechain_first or dns_rbtnodechain_last -- and remember that
817 * dns_rbt_findnode is not guaranteed to point the chain somewhere,
818 * since there may have been no predecessor to the searched for name.
821 *\li The chain is pointed to the predecessor of its current target.
823 *\li 'name' and 'origin', if non-NULL, are set as described for
824 * dns_rbtnodechain_current.
826 *\li 'origin' is only if a new origin was found.
829 *\li #ISC_R_SUCCESS The predecessor was found and 'name' was set.
830 *\li #DNS_R_NEWORIGIN The predecessor was found with a different
831 * origin and 'name' and 'origin' were set.
832 *\li #ISC_R_NOMORE There was no predecessor.
833 *\li <something_else> Any error result from dns_rbtnodechain_current.
837 dns_rbtnodechain_next(dns_rbtnodechain_t *chain, dns_name_t *name,
840 * Adjusts chain to point the DNSSEC successor of the name to which it
841 * is currently pointed.
844 *\li 'chain' is a valid chain.
845 *\li 'chain' has been pointed somewhere in the tree with dns_rbt_findnode,
846 * dns_rbtnodechain_first or dns_rbtnodechain_last -- and remember that
847 * dns_rbt_findnode is not guaranteed to point the chain somewhere,
848 * since there may have been no predecessor to the searched for name.
851 *\li The chain is pointed to the successor of its current target.
853 *\li 'name' and 'origin', if non-NULL, are set as described for
854 * dns_rbtnodechain_current.
856 *\li 'origin' is only if a new origin was found.
859 *\li #ISC_R_SUCCESS The successor was found and 'name' was set.
860 *\li #DNS_R_NEWORIGIN The successor was found with a different
861 * origin and 'name' and 'origin' were set.
862 *\li #ISC_R_NOMORE There was no successor.
863 *\li <something_else> Any error result from dns_name_concatenate.
867 * Wrapper macros for manipulating the rbtnode reference counter:
868 * Since we selectively use isc_refcount_t for the reference counter of
869 * a rbtnode, operations on the counter depend on the actual type of it.
870 * The following macros provide a common interface to these operations,
871 * hiding the back-end. The usage is the same as that of isc_refcount_xxx().
873 #ifdef DNS_RBT_USEISCREFCOUNT
874 #define dns_rbtnode_refinit(node, n) \
876 isc_refcount_init(&(node)->references, (n)); \
878 #define dns_rbtnode_refdestroy(node) \
880 isc_refcount_destroy(&(node)->references); \
882 #define dns_rbtnode_refcurrent(node) \
883 isc_refcount_current(&(node)->references)
884 #define dns_rbtnode_refincrement0(node, refs) \
886 isc_refcount_increment0(&(node)->references, (refs)); \
888 #define dns_rbtnode_refincrement(node, refs) \
890 isc_refcount_increment(&(node)->references, (refs)); \
892 #define dns_rbtnode_refdecrement(node, refs) \
894 isc_refcount_decrement(&(node)->references, (refs)); \
896 #else /* DNS_RBT_USEISCREFCOUNT */
897 #define dns_rbtnode_refinit(node, n) ((node)->references = (n))
898 #define dns_rbtnode_refdestroy(node) (REQUIRE((node)->references == 0))
899 #define dns_rbtnode_refcurrent(node) ((node)->references)
900 #define dns_rbtnode_refincrement0(node, refs) \
902 unsigned int *_tmp = (unsigned int *)(refs); \
903 (node)->references++; \
904 if ((_tmp) != NULL) \
905 (*_tmp) = (node)->references; \
907 #define dns_rbtnode_refincrement(node, refs) \
909 REQUIRE((node)->references > 0); \
910 (node)->references++; \
911 if ((refs) != NULL) \
912 (*refs) = (node)->references; \
914 #define dns_rbtnode_refdecrement(node, refs) \
916 REQUIRE((node)->references > 0); \
917 (node)->references--; \
918 if ((refs) != NULL) \
919 (*refs) = (node)->references; \
921 #endif /* DNS_RBT_USEISCREFCOUNT */
925 #endif /* DNS_RBT_H */