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bind/lib/dns/rbt.c

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/*
* Copyright (C) 1999 Internet Software Consortium.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
* SOFTWARE.
*/
/* $Id: rbt.c,v 1.46 1999/04/22 14:16:52 tale Exp $ */
/* Principal Authors: DCL */
#include <config.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <isc/assertions.h>
#include <isc/boolean.h>
#include <isc/error.h>
#include <isc/mem.h>
#include <isc/result.h>
#include <dns/rbt.h>
#include <dns/result.h>
#include <dns/fixedname.h>
#define RBT_MAGIC 0x5242542BU /* RBT+. */
#define VALID_RBT(rbt) ((rbt) != NULL && (rbt)->magic == RBT_MAGIC)
#define CHAIN_MAGIC 0x302d302dU /* 0-0-. */
#define VALID_CHAIN(chain) ((chain) != NULL && \
(chain)->magic == CHAIN_MAGIC)
struct dns_rbt {
unsigned int magic;
isc_mem_t * mctx;
dns_rbtnode_t * root;
void (*data_deleter)(void *, void *);
void * deleter_arg;
};
#define RED 0
#define BLACK 1
/*
* Elements of the rbtnode structure.
*/
#define LEFT(node) ((node)->left)
#define RIGHT(node) ((node)->right)
#define DOWN(node) ((node)->down)
#define DATA(node) ((node)->data)
#define COLOR(node) ((node)->color)
#define CALLBACK(node) ((node)->find_callback)
#define NAMELEN(node) ((node)->namelen)
#define OFFSETLEN(node) ((node)->offsetlen)
#define ATTRS(node) ((node)->attributes)
#define PADBYTES(node) ((node)->padbytes)
/*
* Structure elements from the rbtdb.c, not
* used as part of the rbt.c algorithms.
*/
#define DIRTY(node) ((node)->dirty)
#define LOCK(node) ((node)->locknum)
#define REFS(node) ((node)->references)
/*
* The variable length stuff stored after the node.
*/
#define NAME(node) ((unsigned char *)((node) + 1))
#define OFFSETS(node) (NAME(node) + NAMELEN(node))
#define NODE_SIZE(node) (sizeof(*node) + \
NAMELEN(node) + OFFSETLEN(node) + PADBYTES(node))
/*
* Color management.
*/
#define IS_RED(node) ((node) != NULL && (node)->color == RED)
#define IS_BLACK(node) ((node) == NULL || (node)->color == BLACK)
#define MAKE_RED(node) ((node)->color = RED)
#define MAKE_BLACK(node) ((node)->color = BLACK)
/*
* Chain management.
*/
#define ADD_ANCESTOR(chain, node) \
do { \
if ((chain)->ancestor_count == (chain)->ancestor_maxitems && \
get_ancestor_mem(chain) != DNS_R_SUCCESS) { \
dns_rbtnodechain_invalidate(chain); \
return (DNS_R_NOMEMORY); \
} \
(chain)->ancestors[(chain)->ancestor_count++] = (node); \
} while (0)
#define ADD_LEVEL(chain, node) \
(chain)->levels[(chain)->level_count++] = (node)
/*
* The following macros directly access normally private name variables.
* These macros are used to avoid a lot of function calls in the critical
* path of the tree traversal code.
*/
#define NODENAME(node, name) \
do { \
(name)->length = NAMELEN(node); \
(name)->labels = OFFSETLEN(node); \
(name)->ndata = NAME(node); \
(name)->offsets = OFFSETS(node); \
(name)->attributes = ATTRS(node); \
(name)->attributes |= DNS_NAMEATTR_READONLY; \
} while (0)
#define FAST_ISABSOLUTE(name) \
(((name)->attributes & DNS_NAMEATTR_ABSOLUTE) ? ISC_TRUE : ISC_FALSE)
#define FAST_COUNTLABELS(name) \
((name)->labels)
#ifdef DEBUG
#define inline
/*
* A little something to help out in GDB.
*/
dns_name_t Name(dns_rbtnode_t *node);
dns_name_t
Name(dns_rbtnode_t *node) {
dns_name_t name;
dns_name_init(&name, NULL);
if (node != NULL)
NODENAME(node, &name);
return (name);
}
#endif
#if defined(ISC_MEM_DEBUG) || defined(RBT_MEM_TEST)
#undef DNS_RBT_ANCESTORBLOCK
#define DNS_RBT_ANCESTORBLOCK 1 /* To give the reallocation code a workout. */
#endif
/*
* Forward declarations.
*/
static dns_result_t create_node(isc_mem_t *mctx,
dns_name_t *name, dns_rbtnode_t **nodep);
static dns_result_t join_nodes(dns_rbt_t *rbt,
dns_rbtnode_t *node, dns_rbtnode_t *parent,
dns_rbtnode_t **rootp);
static inline dns_result_t get_ancestor_mem(dns_rbtnodechain_t *chain);
static inline void put_ancestor_mem(dns_rbtnodechain_t *chain);
static inline void rotate_left(dns_rbtnode_t *node, dns_rbtnode_t *parent,
dns_rbtnode_t **rootp);
static inline void rotate_right(dns_rbtnode_t *node, dns_rbtnode_t *parent,
dns_rbtnode_t **rootp);
static void dns_rbt_addonlevel(dns_rbtnode_t *node,
dns_rbtnode_t *current, int order,
dns_rbtnode_t **rootp,
dns_rbtnodechain_t *chain);
static void dns_rbt_deletefromlevel(dns_rbt_t *rbt,
dns_rbtnode_t *delete,
dns_rbtnodechain_t *chain);
static void dns_rbt_deletetree(dns_rbt_t *rbt, dns_rbtnode_t *node);
static dns_result_t zapnode_and_fixlevels(dns_rbt_t *rbt,
dns_rbtnode_t *node,
isc_boolean_t recurse,
dns_rbtnodechain_t *chain);
/*
* Initialize a red/black tree of trees.
*/
dns_result_t
dns_rbt_create(isc_mem_t *mctx, void (*deleter)(void *, void *),
void *deleter_arg, dns_rbt_t **rbtp)
{
dns_rbt_t *rbt;
REQUIRE(mctx != NULL);
REQUIRE(rbtp != NULL && *rbtp == NULL);
REQUIRE(deleter == NULL ? deleter_arg == NULL : 1);
rbt = (dns_rbt_t *)isc_mem_get(mctx, sizeof(*rbt));
if (rbt == NULL)
return (DNS_R_NOMEMORY);
rbt->mctx = mctx;
rbt->data_deleter = deleter;
rbt->deleter_arg = deleter_arg;
rbt->root = NULL;
rbt->magic = RBT_MAGIC;
*rbtp = rbt;
return (DNS_R_SUCCESS);
}
/*
* Deallocate a red/black tree of trees.
*/
void
dns_rbt_destroy(dns_rbt_t **rbtp) {
dns_rbt_t *rbt;
REQUIRE(rbtp != NULL && VALID_RBT(*rbtp));
rbt = *rbtp;
dns_rbt_deletetree(rbt, rbt->root);
rbt->magic = 0;
isc_mem_put(rbt->mctx, rbt, sizeof(*rbt));
*rbtp = NULL;
}
/*
* The next three functions for chains, get_ancestor_mem, put_ancestor_mem
* and chain_name, appear early in this file so they can be effectively
* inlined by the other rbt functions that use them.
*/
static inline dns_result_t
get_ancestor_mem(dns_rbtnodechain_t *chain) {
dns_rbtnode_t **ancestor_mem;
int oldsize, newsize;
oldsize = chain->ancestor_maxitems * sizeof(dns_rbtnode_t *);
newsize = oldsize + DNS_RBT_ANCESTORBLOCK * sizeof(dns_rbtnode_t *);
if (oldsize == 0) {
chain->ancestors = chain->ancestor_block;
} else {
ancestor_mem = isc_mem_get(chain->mctx, newsize);
if (ancestor_mem == NULL)
return (DNS_R_NOMEMORY);
memcpy(ancestor_mem, chain->ancestors, oldsize);
if (chain->ancestor_maxitems > DNS_RBT_ANCESTORBLOCK)
isc_mem_put(chain->mctx, chain->ancestors, oldsize);
chain->ancestors = ancestor_mem;
}
chain->ancestor_maxitems += DNS_RBT_ANCESTORBLOCK;
return (DNS_R_SUCCESS);
}
/*
* This is used by functions that are popping the chain off their
* own stack, and so do not need to have ancestor_maxitems or the
* ancestors pointer reset. Functions that will be reusing a chain
* structure need to call dns_rbtnodechain_reset() instead.
*/
static inline void
put_ancestor_mem(dns_rbtnodechain_t *chain) {
if (chain->ancestor_maxitems > DNS_RBT_ANCESTORBLOCK)
isc_mem_put(chain->mctx, chain->ancestors,
chain->ancestor_maxitems
* sizeof(dns_rbtnode_t *));
}
static inline dns_result_t
chain_name(dns_rbtnodechain_t *chain, dns_name_t *name,
isc_boolean_t include_chain_end)
{
dns_name_t nodename;
dns_result_t result;
unsigned int i;
dns_name_init(&nodename, NULL);
/*
* XXX DCL Is this too devilish, initializing name like this?
*/
result = dns_name_concatenate(NULL, NULL, name, NULL);
if (result != DNS_R_SUCCESS)
return result;
for (i = 0; i < chain->level_count; i++) {
NODENAME(chain->levels[i], &nodename);
result = dns_name_concatenate(&nodename, name, name, NULL);
if (result != DNS_R_SUCCESS)
break;
}
if (result == DNS_R_SUCCESS &&
include_chain_end && chain->end != NULL) {
NODENAME(chain->end, &nodename);
result = dns_name_concatenate(&nodename, name, name, NULL);
}
return (result);
}
static inline dns_result_t
move_chain_to_last(dns_rbtnodechain_t *chain, dns_rbtnode_t *node) {
while (1) {
/*
* Go as far right and then down as much as possible,
* as long as the rightmost node has a down pointer.
*/
while (RIGHT(node) != NULL) {
ADD_ANCESTOR(chain, node);
node = RIGHT(node);
}
if (DOWN(node) == NULL)
break;
ADD_ANCESTOR(chain, NULL);
ADD_LEVEL(chain, node);
node = DOWN(node);
}
chain->end = node;
return (DNS_R_SUCCESS);
}
/*
* Add 'name' to tree, initializing its data pointer with 'data'.
*/
dns_result_t
dns_rbt_addnode(dns_rbt_t *rbt, dns_name_t *name, dns_rbtnode_t **nodep) {
/*
* Does this thing have too many variables or what?
*/
dns_rbtnode_t **root, *parent, *child, *current, *new_current;
dns_name_t add_name, current_name, new_name, tmp_name;
dns_offsets_t add_offsets, current_offsets, new_offsets, tmp_offsets;
dns_namereln_t compared;
dns_result_t result;
dns_rbtnodechain_t chain;
isc_region_t r;
unsigned int add_labels, current_labels, keep_labels, start_label;
unsigned int common_labels, common_bits;
int order;
REQUIRE(VALID_RBT(rbt));
REQUIRE(FAST_ISABSOLUTE(name));
REQUIRE(nodep != NULL && *nodep == NULL);
/*
* Create a copy of the name so the original name structure is
* not modified.
*/
dns_name_init(&add_name, add_offsets);
dns_name_toregion(name, &r);
dns_name_fromregion(&add_name, &r);
if (rbt->root == NULL) {
result = create_node(rbt->mctx, &add_name, &new_current);
if (result == DNS_R_SUCCESS) {
rbt->root = new_current;
*nodep = new_current;
}
return (result);
}
dns_rbtnodechain_init(&chain, rbt->mctx);
ADD_ANCESTOR(&chain, NULL);
root = &rbt->root;
parent = NULL;
current = NULL;
child = *root;
dns_name_init(&current_name, current_offsets);
do {
current = child;
NODENAME(current, &current_name);
compared = dns_name_fullcompare(&add_name, &current_name,
&order,
&common_labels, &common_bits);
if (compared == dns_namereln_equal) {
*nodep = current;
put_ancestor_mem(&chain);
return (DNS_R_EXISTS);
}
if (compared == dns_namereln_none) {
if (order < 0) {
parent = current;
child = LEFT(current);
ADD_ANCESTOR(&chain, current);
} else if (order > 0) {
parent = current;
child = RIGHT(current);
ADD_ANCESTOR(&chain, current);
}
} else {
/*
* This name has some suffix in common with the
* name at the current node. If the name at
* the current node is shorter, that means the
* new name should be in a subtree. If the
* name at the current node is longer, that means
* the down pointer to this tree should point
* to a new tree that has the common suffix, and
* the non-common parts of these two names should
* start a new tree.
*/
add_labels = FAST_COUNTLABELS(&add_name);
current_labels = FAST_COUNTLABELS(&current_name);
if (compared == dns_namereln_subdomain &&
common_bits == 0) {
/*
* All of the exising labels are in common,
* so the new name is in a subtree.
* First, turn the non-in-common part of
* &add_name into its own dns_name_t to be
* searched for in the downtree.
*/
start_label = 0;
keep_labels = add_labels - common_labels;
dns_name_getlabelsequence(&add_name,
start_label,
keep_labels,
&add_name);
/*
* Follow the down pointer (possibly NULL).
*/
root = &DOWN(current);
parent = NULL;
child = DOWN(current);
ADD_ANCESTOR(&chain, NULL);
ADD_LEVEL(&chain, current);
} else {
/*
* The number of labels in common is fewer
* than the number of labels at the current
* node, so the current node must be adjusted
* to have just the common suffix, and a down
* pointer made to a new tree.
*/
INSIST(compared == dns_namereln_commonancestor
|| compared == dns_namereln_contains
|| (compared == dns_namereln_subdomain
&& common_bits > 0));
/*
* Ensure the number of levels in the tree
* does not exceed the number of logical
* levels allowed by DNSSEC.
*
* XXX DCL need a better error result?
*/
if (chain.level_count ==
(sizeof(chain.levels) /
sizeof(*chain.levels)))
return (DNS_R_NOSPACE);
/* XXX DCL handle bitstrings.
* When common_bits is non-zero, the last label
* in common (eg, vix in a.vix.com vs
* b.vix.com) is a bit label and common_bits is
* how many are in common. To split the node,
* the node in question will have to split into
* two bitstrings. A comment in name.h says,
* "Some provision still needs to be made for
* splitting bitstring labels," and Bob has
* pushed this down on the priority list,
* so for now splitting on bitstrings does not
* work.
*/
/*
* Get the common labels of the current name.
*/
start_label = current_labels - common_labels;
keep_labels = common_labels;
dns_name_init(&tmp_name, tmp_offsets);
dns_name_getlabelsequence(&current_name,
start_label,
keep_labels,
&tmp_name);
result = create_node(rbt->mctx,
&tmp_name, &new_current);
if (result != DNS_R_SUCCESS) {
put_ancestor_mem(&chain);
return (result);
}
/*
* Reproduce the tree attributes of the
* current node.
*/
LEFT(new_current) = LEFT(current);
RIGHT(new_current) = RIGHT(current);
COLOR(new_current) = COLOR(current);
/*
* Fix pointers that were to the current node.
*/
if (parent != NULL)
if (LEFT(parent) == current)
LEFT(parent) = new_current;
else
RIGHT(parent) = new_current;
if (*root == current)
*root = new_current;
/*
* Now create the new root of the subtree
* as the not-in-common labels of the current
* node, keeping the same memory location so
* as not to break any external references to
* the node. The down pointer and name data
* are preserved, while left and right
* pointers are nullified when the node is
* established as the start of the next level.
*/
start_label = 0;
keep_labels = current_labels - common_labels;
dns_name_init(&new_name, new_offsets);
dns_name_getlabelsequence(&current_name,
start_label,
keep_labels,
&new_name);
/*
* The name stored at the node is effectively
* truncated in place by setting the shorter
* name length, moving the offsets to the
* end of the truncated name, and then
* updating PADBYTES to reflect the truncation.
*/
NAMELEN(current) = new_name.length;
OFFSETLEN(current) = keep_labels;
memcpy(OFFSETS(current), new_name.offsets,
keep_labels);
PADBYTES(current) +=
(current_name.length - new_name.length)
+ (current_labels - keep_labels);
/*
* Set up the new root of the next level.
* By definition it will not be the top
* level tree, so clear DNS_NAMEATTR_ABSOLUTE.
*/
DOWN(new_current) = current;
root = &DOWN(new_current);
ADD_ANCESTOR(&chain, NULL);
ADD_LEVEL(&chain, new_current);
LEFT(current) = NULL;
RIGHT(current) = NULL;
MAKE_BLACK(current);
ATTRS(current) &= ~DNS_NAMEATTR_ABSOLUTE;
if (common_labels == add_labels) {
/*
* The name has been added by pushing
* the not-in-common parts down to
* a new level.
*/
*nodep = new_current;
put_ancestor_mem(&chain);
return (DNS_R_SUCCESS);
} else {
/*
* The current node has no data,
* because it is just a placeholder.
* Its data pointer is already NULL
* from create_node()).
*/
/* The not-in-common parts of the new
* name will be inserted into the new
* level following this loop.
*/
start_label = 0;
keep_labels =
add_labels - common_labels;
dns_name_getlabelsequence(&add_name,
start_label,
keep_labels,
&add_name);
child = NULL;
ADD_ANCESTOR(&chain, current);
}
}
}
} while (child != NULL);
result = create_node(rbt->mctx, &add_name, &new_current);
if (result == DNS_R_SUCCESS) {
dns_rbt_addonlevel(new_current, current, order, root, &chain);
*nodep = new_current;
}
put_ancestor_mem(&chain);
return (result);
}
/*
* Add a name to the tree of trees, associating it with some data.
*/
dns_result_t
dns_rbt_addname(dns_rbt_t *rbt, dns_name_t *name, void *data) {
dns_result_t result;
dns_rbtnode_t *node;
REQUIRE(VALID_RBT(rbt));
REQUIRE(FAST_ISABSOLUTE(name));
node = NULL;
result = dns_rbt_addnode(rbt, name, &node);
/*
* dns_rbt_addnode will report the node exists even when
* it does not have data associated with it, but the
* dns_rbt_*name functions all behave depending on whether
* there is data associated with a node.
*/
if (result == DNS_R_SUCCESS ||
(result == DNS_R_EXISTS && DATA(node) == NULL)) {
DATA(node) = data;
result = DNS_R_SUCCESS;
}
return (result);
}
/*
* Find the node for "name" in the tree of trees.
*/
dns_result_t
dns_rbt_findnode(dns_rbt_t *rbt, dns_name_t *name, dns_name_t *foundname,
dns_rbtnode_t **node, dns_rbtnodechain_t *chain,
isc_boolean_t empty_data_ok, dns_rbtfindcallback_t callback,
void *callback_arg)
{
dns_rbtnode_t *current;
dns_rbtnodechain_t localchain;
dns_name_t *search_name, *current_name, *tmp_name, *callback_name;
dns_name_t name1, name2;
dns_offsets_t name1_offsets, name2_offsets;
dns_fixedname_t fixedcallbackname;
dns_namereln_t compared;
dns_result_t result, saved_result;
isc_region_t r;
unsigned int common_labels, common_bits;
unsigned int first_common_label;
int order;
REQUIRE(VALID_RBT(rbt));
REQUIRE(FAST_ISABSOLUTE(name));
REQUIRE(node != NULL && *node == NULL);
/*
* If there is a chain it needs to appear to be in a sane state,
* otherwise a chain is still needed to generate foundname and
* callback_name.
*/
if (chain == NULL) {
chain = &localchain;
dns_rbtnodechain_init(chain, rbt->mctx);
} else
dns_rbtnodechain_reset(chain);
dns_fixedname_init(&fixedcallbackname);
callback_name = dns_fixedname_name(&fixedcallbackname);
dns_name_init(&name1, name1_offsets);
dns_name_init(&name2, name2_offsets);
/*
* search_name is the name segment being sought in each tree level.
* Ensure that it has offsets by making a copy into a structure
* that has offsets.
*/
if (name->offsets == NULL) {
search_name = &name1;
dns_name_toregion(name, &r);
dns_name_fromregion(search_name, &r);
} else
search_name = name;
current_name = &name2;
ADD_ANCESTOR(chain, NULL);
saved_result = DNS_R_SUCCESS;
current = rbt->root;
while (current != NULL) {
NODENAME(current, current_name);
compared = dns_name_fullcompare(search_name, current_name,
&order,
&common_labels, &common_bits);
if (compared == dns_namereln_equal)
break;
if (compared == dns_namereln_none) {
ADD_ANCESTOR(chain, current);
/*
* Standard binary search tree movement.
*/
if (order < 0)
current = LEFT(current);
else
current = RIGHT(current);
} else {
/*
* The names have some common suffix labels.
*
* If the number in common are equal in length to
* the current node's name length, then follow the
* down pointer and search in the new tree.
*/
if (compared == dns_namereln_subdomain &&
common_bits == 0) {
/*
* Set up new name to search for as
* the not-in-common part.
*/
if (search_name == &name2) {
current_name = &name2;
tmp_name = &name1;
dns_name_init(tmp_name, name1_offsets);
} else {
current_name = &name1;
tmp_name = &name2;
dns_name_init(tmp_name, name2_offsets);
}
first_common_label =
FAST_COUNTLABELS(search_name)
- common_labels;
/*
* Whack off the current node's common labels
* for the name to search in the next level.
*/
dns_name_getlabelsequence(search_name, 0,
first_common_label,
tmp_name);
search_name = tmp_name;
/*
* This might be the closest enclosing name.
*/
if (empty_data_ok || DATA(current) != NULL)
*node = current;
/*
* Point the chain to the next level. This
* needs to be done before 'current' is pointed
* there because the callback in the next
* block of code needs the current 'current',
* but in the event the callback requests that
* the search be stopped then the
* DNS_R_PARTIALMATCH code at the end of this
* function needs the chain pointed to the
* next level.
*/
ADD_ANCESTOR(chain, NULL);
ADD_LEVEL(chain, current);
chain->level_matches++;
/*
* The caller may want to interrupt the
* downward search when certain special nodes
* are traversed. If this is a special node,
* the callback is used to learn what the
* caller wants to do.
*/
if (callback != NULL && CALLBACK(current)) {
result = chain_name(chain,
callback_name,
ISC_FALSE);
if (result != DNS_R_SUCCESS) {
dns_rbtnodechain_reset(chain);
return (result);
}
result = (callback)(current,
callback_name,
callback_arg);
if (result != DNS_R_CONTINUE) {
saved_result = result;
/*
* Treat this node as if it
* had no down pointer.
*/
current = NULL;
break;
}
}
/*
* Finally, head to the next tree level.
*/
current = DOWN(current);
} else {
/*
* Though there are labels in common, the
* entire name at this node is not common
* with the search name so the search
* name does not exist in the tree.
* Add this node to the ancestor chain
* to simplify things for the chain fixing
* logic below then end the loop.
*/
INSIST(compared == dns_namereln_commonancestor
|| compared == dns_namereln_contains
|| (compared == dns_namereln_subdomain
&& common_bits > 0));
ADD_ANCESTOR(chain, current);
current = NULL;
}
}
}
if (current != NULL) {
chain->end = current;
if (foundname != NULL)
result = chain_name(chain, foundname, ISC_TRUE);
else
result = DNS_R_SUCCESS;
if (result == DNS_R_SUCCESS) {
*node = current;
result = saved_result;
} else
*node = NULL;
} else {
if (*node != NULL) {
if (foundname != NULL) {
/*
* Unwind the chain to the partial match node
* to derive the name.
*/
unsigned int saved_count = chain->level_count;
while (chain->levels[chain->level_count - 1] !=
*node) {
INSIST(chain->level_count > 1);
chain->level_count--;
}
result = chain_name(chain, foundname,
ISC_FALSE);
chain->level_count = saved_count;
} else
result = DNS_R_SUCCESS;
if (result == DNS_R_SUCCESS)
result = DNS_R_PARTIALMATCH;
} else
result = DNS_R_NOTFOUND;
if (chain != &localchain) {
/*
* The chain argument needs to be pointed at the
* DNSSEC predecessor of the search name.
*
* First, point current to the node that stopped the
* search, and remove that node from the ancestor
* history.
*/
INSIST(chain->ancestor_count > 0);
current = chain->ancestors[--chain->ancestor_count];
if (current == NULL) {
/*
* Attempted to follow a down pointer that was
* NULL, which means the searched for name was
* a subdomain of a terminal name in the tree.
* Since there are no existing subdomains to
* order against, the terminal name is the
* predecessor.
*/
INSIST(chain->level_count > 0 &&
chain->level_matches > 0);
chain->end =
chain->levels[--chain->level_count];
chain->level_matches--;
} else {
dns_result_t result2;
/*
* Reached a point within a level tree that
* positively indicates the name is not
* present, but the stop node could be either
* less than the desired name (order > 0) or
* greater than the desired name (order < 0).
*
* If the stop node is less, it is not
* necessarily the predecessor. If the stop
* node has a down pointer, then the real
* predecessor is at the end of a level below
* (not necessarily the next level).
* Move down levels until the rightmost node
* does not have a down pointer.
*
* When the stop node is greater, it is
* the successor. All the logic for finding
* the predecessor is handily encapsulated
* in dns_rbtnodechain_prev. In the event
* that the search name is less than anything
* else in the tree, the chain is reset.
* XXX DCL What is the best way for the caller
* to know that the search name has
* no predecessor?
*/
if (order > 0) {
if (DOWN(current) != NULL) {
ADD_ANCESTOR(chain, NULL);
ADD_LEVEL(chain, current);
result2 =
move_chain_to_last(chain,
DOWN(current));
if (result2 != DNS_R_SUCCESS)
result = result2;
} else
/*
* Ah, the pure and simple
* case. The stop node is the
* predecessor.
*/
chain->end = current;
} else {
INSIST(order < 0);
chain->end = current;
result2 = dns_rbtnodechain_prev(chain,
NULL,
NULL);
if (result2 == DNS_R_SUCCESS ||
result2 == DNS_R_NEWORIGIN)
; /* Nothing */
else if (result2 == DNS_R_NOMORE)
dns_rbtnodechain_reset(chain);
else
result = result2;
}
}
}
}
if (chain == &localchain)
put_ancestor_mem(chain);
return (result);
}
/*
* Get the data pointer associated with 'name'.
*/
dns_result_t
dns_rbt_findname(dns_rbt_t *rbt, dns_name_t *name,
dns_name_t *foundname, void **data) {
dns_rbtnode_t *node = NULL;
dns_result_t result;
REQUIRE(data != NULL && *data == NULL);
result = dns_rbt_findnode(rbt, name, foundname, &node, NULL,
ISC_FALSE, NULL, NULL);
if (node != NULL && DATA(node) != NULL)
*data = DATA(node);
else
result = DNS_R_NOTFOUND;
return (result);
}
/*
* Delete a name from the tree of trees.
*/
dns_result_t
dns_rbt_deletename(dns_rbt_t *rbt, dns_name_t *name, isc_boolean_t recurse) {
dns_rbtnode_t *node = NULL;
dns_result_t result;
dns_rbtnodechain_t chain;
REQUIRE(VALID_RBT(rbt));
REQUIRE(FAST_ISABSOLUTE(name));
/*
* Find the node, building the ancestor chain.
*
* When searching, the name might not have an exact match:
* consider a.b.a.com, b.b.a.com and c.b.a.com as the only
* elements of a tree, which would make layer 1 a single
* node tree of "b.a.com" and layer 2 a three node tree of
* a, b, and c. Deleting a.com would find only a partial depth
* match in the first layer. Should it be a requirement that
* that the name to be deleted have data? For now, it is.
*
* ->dirty, ->locknum and ->references are ignored; they are
* solely the province of rbtdb.c.
*/
dns_rbtnodechain_init(&chain, rbt->mctx);
result = dns_rbt_findnode(rbt, name, NULL, &node, &chain, ISC_FALSE,
NULL, NULL);
/*
* The guts of this routine are in a separate function (which
* is called only once, by this function) to make freeing the
* ancestor memory easier, since there are several different
* exit points from the level checking logic.
*/
if (result == DNS_R_SUCCESS) {
if (DATA(node) != NULL)
result = zapnode_and_fixlevels(rbt, node,
recurse, &chain);
else
result = DNS_R_NOTFOUND;
} else if (result == DNS_R_PARTIALMATCH)
result = DNS_R_NOTFOUND;
put_ancestor_mem(&chain);
return (result);
}
/*
*
*/
static dns_result_t
zapnode_and_fixlevels(dns_rbt_t *rbt, dns_rbtnode_t *node,
isc_boolean_t recurse, dns_rbtnodechain_t *chain) {
dns_rbtnode_t *down, *parent, **rootp;
dns_result_t result;
down = DOWN(node);
if (down != NULL) {
if (recurse) {
dns_rbt_deletetree(rbt, down);
down = NULL;
} else {
if (rbt->data_deleter != NULL)
rbt->data_deleter(DATA(node),
rbt->deleter_arg);
DATA(node) = NULL;
if (LEFT(down) != NULL || RIGHT(down) != NULL)
/*
* This node cannot be removed because it
* points down to a level that has more than
* one node, so it must continue to serve
* as the root for that level. All that
* could be done was to blast its data.
*/
return (DNS_R_SUCCESS);
/*
* There is a down pointer to a level with a single
* item. That item's name can be joined with the name
* on this level.
*/
INSIST(chain->ancestor_count > 0);
rootp = chain->level_count > 0 ?
&DOWN(chain->levels[chain->level_count - 1]) :
&rbt->root;
parent = chain->ancestors[chain->ancestor_count - 1];
result = join_nodes(rbt, node, parent, rootp);
return (result);
}
}
/*
* This node now has no down pointer (either because it didn't
* have one to start, or because it was recursively removed).
* So now the node needs to be removed from this level.
*/
dns_rbt_deletefromlevel(rbt, node, chain);
if (rbt->data_deleter != NULL)
rbt->data_deleter(DATA(node), rbt->deleter_arg);
isc_mem_put(rbt->mctx, node, NODE_SIZE(node));
/*
* Everything is successful, unless the next block fails.
*/
result = DNS_R_SUCCESS;
/*
* If there is one node left on this level, and the node one level up
* that points down to here has no data, then those two nodes can be
* merged. The focus for exploring this criteria is shifted up one
* level.
*/
node = chain->level_count > 0 ?
chain->levels[chain->level_count - 1] : NULL;
if (node != NULL && DATA(node) == NULL &&
LEFT(DOWN(node)) == NULL && RIGHT(DOWN(node)) == NULL) {
rootp = chain->level_count > 1 ?
&DOWN(chain->levels[chain->level_count - 2]) :
&rbt->root;
/*
* The search to find the original node went through the
* node that is now being examined. It might have been
*
* current_node -down-to-> deleted_node ... or ...
*
* current_node -down-to-> remaining_node -left/right-to->
* deleted_node
*
* In the first case, ancestor_count - 1 is NULL and - 2
* is the parent of current_node (possibly also NULL).
* In the second case, ancestor_count - 1 is remaining_node,
* - 2, is NULL and - 3 is the parent of current_node.
*/
parent = chain->ancestors[chain->ancestor_count - 1] == NULL ?
chain->ancestors[chain->ancestor_count - 2] :
chain->ancestors[chain->ancestor_count - 3];
result = join_nodes(rbt, node, parent, rootp);
}
return (result);
}
void
dns_rbt_namefromnode(dns_rbtnode_t *node, dns_name_t *name) {
REQUIRE(name->offsets == NULL);
NODENAME(node, name);
}
static dns_result_t
create_node(isc_mem_t *mctx, dns_name_t *name, dns_rbtnode_t **nodep) {
dns_rbtnode_t *node;
isc_region_t region;
unsigned int labels;
REQUIRE(name->offsets != NULL);
dns_name_toregion(name, &region);
labels = FAST_COUNTLABELS(name);
ENSURE(labels > 0);
/*
* Allocate space for the node structure, the name, and the offsets.
*/
node = (dns_rbtnode_t *)isc_mem_get(mctx, sizeof(*node) +
region.length + labels);
if (node == NULL)
return (DNS_R_NOMEMORY);
RIGHT(node) = NULL;
LEFT(node) = NULL;
DOWN(node) = NULL;
DATA(node) = NULL;
LOCK(node) = 0;
REFS(node) = 0;
DIRTY(node) = 0;
MAKE_BLACK(node);
CALLBACK(node) = 0;
/*
* The following is stored to make reconstructing a name from the
* stored value in the node easy: the length of the name, the number
* of labels, whether the name is absolute or not, the name itself,
* and the name's offsets table.
*
* XXX RTH
* The offsets table could be made smaller by eliminating the
* first offset, which is always 0. This requires changes to
* lib/dns/name.c.
*/
NAMELEN(node) = region.length;
PADBYTES(node) = 0;
OFFSETLEN(node) = labels;
ATTRS(node) = name->attributes;
memcpy(NAME(node), region.base, region.length);
memcpy(OFFSETS(node), name->offsets, labels);
*nodep = node;
return (DNS_R_SUCCESS);
}
static dns_result_t
join_nodes(dns_rbt_t *rbt,
dns_rbtnode_t *node, dns_rbtnode_t *parent, dns_rbtnode_t **rootp) {
dns_rbtnode_t *down, *newnode;
dns_result_t result;
dns_name_t newname;
dns_offsets_t offsets;
isc_region_t r;
int newlabels, newsize;
REQUIRE(VALID_RBT(rbt));
REQUIRE(node != NULL);
REQUIRE(DATA(node) == NULL && DOWN(node) != NULL);
down = DOWN(node);
newsize = NAMELEN(node) + NAMELEN(down);
newlabels = OFFSETLEN(node) + OFFSETLEN(down);
r.base = isc_mem_get(rbt->mctx, newsize);
if (r.base == NULL)
return (DNS_R_NOMEMORY);
memcpy(r.base, NAME(down), NAMELEN(down));
memcpy(r.base + NAMELEN(down), NAME(node), NAMELEN(node));
r.length = newsize;
dns_name_init(&newname, offsets);
dns_name_fromregion(&newname, &r);
/*
* Check whether the space needed for the joined names can
* fit within the space already available in the down node,
* so that any external references to the down node are preserved.
*
* Currently this is not very meaningful since preservation
* of the address of the down node cannot be guaranteed.
*/
if (newsize + newlabels >=
NAMELEN(down) + OFFSETLEN(down) + PADBYTES(down))
result = create_node(rbt->mctx, &newname, &newnode);
else {
memcpy(NAME(down) + NAMELEN(down), NAME(node), NAMELEN(node));
NAMELEN(down) = newsize;
OFFSETLEN(down) = newlabels;
memcpy(OFFSETS(down), newname.offsets, newlabels);
newnode = down;
result = DNS_R_SUCCESS;
}
if (result == DNS_R_SUCCESS) {
COLOR(newnode) = COLOR(node);
RIGHT(newnode) = RIGHT(node);
LEFT(newnode) = LEFT(node);
DOWN(newnode) = DOWN(down);
DATA(newnode) = DATA(down);
/*
* Fix the pointers to the original node.
*/
if (parent != NULL) {
if (LEFT(parent) == node)
LEFT(parent) = newnode;
else
RIGHT(parent) = newnode;
} else
*rootp = newnode;
isc_mem_put(rbt->mctx, node, NODE_SIZE(node));
if (newnode != down) {
isc_mem_put(rbt->mctx, down, NODE_SIZE(down));
isc_mem_put(rbt->mctx, r.base, r.length);
}
}
return (result);
}
static inline void
rotate_left(dns_rbtnode_t *node, dns_rbtnode_t *parent, dns_rbtnode_t **rootp) {
dns_rbtnode_t *child;
REQUIRE(node != NULL);
REQUIRE(rootp != NULL);
child = RIGHT(node);
REQUIRE(child != NULL);
RIGHT(node) = LEFT(child);
LEFT(child) = node;
if (parent != NULL) {
if (LEFT(parent) == node)
LEFT(parent) = child;
else
RIGHT(parent) = child;
} else
*rootp = child;
}
static inline void
rotate_right(dns_rbtnode_t *node, dns_rbtnode_t *parent, dns_rbtnode_t **rootp)
{
dns_rbtnode_t *child;
REQUIRE(node != NULL);
REQUIRE(rootp != NULL);
child = LEFT(node);
REQUIRE(child != NULL);
LEFT(node) = RIGHT(child);
RIGHT(child) = node;
if (parent != NULL) {
if (LEFT(parent) == node)
LEFT(parent) = child;
else
RIGHT(parent) = child;
} else
*rootp = child;
}
/*
* This is the real workhorse of the insertion code, because it does the
* true red/black tree on a single level.
*/
static void
dns_rbt_addonlevel(dns_rbtnode_t *node,
dns_rbtnode_t *current, int order,
dns_rbtnode_t **rootp, dns_rbtnodechain_t *chain)
{
dns_rbtnode_t *child, *root, *tmp, *parent, *grandparent;
dns_name_t add_name, current_name;
dns_offsets_t add_offsets, current_offsets;
unsigned int depth;
REQUIRE(rootp != NULL);
REQUIRE(node != NULL && LEFT(node) == NULL && RIGHT(node) == NULL);
REQUIRE(current != NULL && LEFT(node) == NULL && RIGHT(node) == NULL);
root = *rootp;
if (root == NULL) {
MAKE_BLACK(node);
*rootp = node;
return;
}
child = root;
dns_name_init(&add_name, add_offsets);
NODENAME(node, &add_name);
dns_name_init(&current_name, current_offsets);
NODENAME(current, &current_name);
if (order < 0)
LEFT(current) = node;
else
RIGHT(current) = node;
MAKE_RED(node);
depth = chain->ancestor_count - 1;
while (node != root && IS_RED(chain->ancestors[depth])) {
INSIST(depth > 0);
parent = chain->ancestors[depth];
grandparent = chain->ancestors[depth - 1];
if (parent == LEFT(grandparent)) {
child = RIGHT(grandparent);
if (child != NULL && IS_RED(child)) {
MAKE_BLACK(parent);
MAKE_BLACK(child);
MAKE_RED(grandparent);
node = grandparent;
depth -= 2;
} else {
if (node == RIGHT(parent)) {
rotate_left(parent, grandparent,
&root);
tmp = node;
node = parent;
parent = tmp;
chain->ancestors[depth] = parent;
}
MAKE_BLACK(parent);
MAKE_RED(grandparent);
INSIST(depth > 1);
rotate_right(grandparent,
chain->ancestors[depth - 2],
&root);
}
} else {
child = LEFT(grandparent);
if (child != NULL && IS_RED(child)) {
MAKE_BLACK(parent);
MAKE_BLACK(child);
MAKE_RED(grandparent);
node = grandparent;
depth -= 2;
} else {
if (node == LEFT(parent)) {
rotate_right(parent, grandparent,
&root);
tmp = node;
node = parent;
parent = tmp;
chain->ancestors[depth] = parent;
}
MAKE_BLACK(parent);
MAKE_RED(grandparent);
INSIST(depth > 1);
rotate_left(grandparent,
chain->ancestors[depth - 2],
&root);
}
}
}
MAKE_BLACK(root);
*rootp = root;
return;
}
/*
* This is the real workhorse of the deletion code, because it does the
* true red/black tree on a single level.
*
* The ancestor and level history _must_ be set with dns_rbt_findnode for
* this function to work properly.
*/
static void
dns_rbt_deletefromlevel(dns_rbt_t *rbt, dns_rbtnode_t *delete,
dns_rbtnodechain_t *chain) {
dns_rbtnode_t *sibling, *parent, *grandparent, *child;
dns_rbtnode_t *successor, **rootp;
int depth;
REQUIRE(VALID_RBT(rbt));
REQUIRE(delete);
REQUIRE(chain->ancestor_count > 0);
parent = chain->ancestors[chain->ancestor_count - 1];
if (chain->level_count > 0)
rootp = &DOWN(chain->levels[chain->level_count - 1]);
else
rootp = &rbt->root;
/*
* Verify that the ancestor/level history is (apparently) correct.
*/
REQUIRE((parent == NULL && *rootp == delete) ||
(parent != NULL &&
(LEFT(parent) == delete || RIGHT(parent) == delete)));
child = NULL;
if (LEFT(delete) == NULL)
if (RIGHT(delete) == NULL) {
if (chain->ancestors[chain->ancestor_count - 1]
== NULL) {
/*
* This is the only item in the tree.
*/
*rootp = NULL;
return;
}
} else
/*
* This node has one child, on the right.
*/
child = RIGHT(delete);
else if (RIGHT(delete) == NULL)
/*
* This node has one child, on the left.
*/
child = LEFT(delete);
else {
dns_rbtnode_t holder, *tmp = &holder;
/*
* This node has two children, so it cannot be directly
* deleted. Find its immediate in-order successor and
* move it to this location, then do the deletion at the
* old site of the successor.
*/
depth = chain->ancestor_count++;
successor = RIGHT(delete);
while (LEFT(successor) != NULL) {
chain->ancestors[chain->ancestor_count++] = successor;
successor = LEFT(successor);
}
/*
* The successor cannot possibly have a left child;
* if there is any child, it is on the right.
*/
if (RIGHT(successor))
child = RIGHT(successor);
/* Swap the two nodes; it would be simpler to just replace
* the value being deleted with that of the successor,
* but this rigamarole is done so the caller has complete
* control over the pointers (and memory allocation) of
* all of nodes. If just the key value were removed from
* the tree, the pointer to the node would would be
* unchanged.
*/
/*
* First, put the successor in the tree location of the
* node to be deleted.
*/
memcpy(tmp, successor, sizeof(dns_rbtnode_t));
chain->ancestors[depth] = successor;
parent = chain->ancestors[depth - 1];
if (parent)
if (LEFT(parent) == delete)
LEFT(parent) = successor;
else
RIGHT(parent) = successor;
else
*rootp = successor;
LEFT(successor) = LEFT(delete);
RIGHT(successor) = RIGHT(delete);
COLOR(successor) = COLOR(delete);
/*
* Now relink the node to be deleted into the
* successor's previous tree location.
*/
parent = chain->ancestors[chain->ancestor_count - 1];
if (parent == successor)
RIGHT(parent) = delete;
else
LEFT(parent) = delete;
/*
* Original location of successor node has no left.
*/
LEFT(delete) = NULL;
RIGHT(delete) = RIGHT(tmp);
COLOR(delete) = COLOR(tmp);
}
parent = chain->ancestors[chain->ancestor_count - 1];
/*
* Remove the node by removing the links from its parent.
*/
if (parent != NULL) {
if (LEFT(parent) == delete) {
LEFT(parent) = child;
sibling = RIGHT(parent);
} else {
RIGHT(parent) = child;
sibling = LEFT(parent);
}
} else {
/*
* This is the root being deleted, and at this point
* it is known to have just one child.
*/
sibling = NULL;
*rootp = child;
}
/*
* Fix color violations.
*/
if (IS_BLACK(delete)) {
dns_rbtnode_t *parent;
depth = chain->ancestor_count - 1;
while (child != *rootp && IS_BLACK(child)) {
parent = chain->ancestors[depth--];
grandparent = chain->ancestors[depth];
if (LEFT(parent) == child) {
sibling = RIGHT(parent);
if (IS_RED(sibling)) {
MAKE_BLACK(sibling);
MAKE_RED(parent);
rotate_left(parent, grandparent,
rootp);
sibling = RIGHT(parent);
}
if (IS_BLACK(LEFT(sibling)) &&
IS_BLACK(RIGHT(sibling))) {
MAKE_RED(sibling);
child = parent;
} else {
if (IS_BLACK(RIGHT(sibling))) {
MAKE_BLACK(LEFT(sibling));
MAKE_RED(sibling);
rotate_right(sibling,
grandparent,
rootp);
sibling = RIGHT(parent);
}
COLOR(sibling) = COLOR(parent);
MAKE_BLACK(parent);
MAKE_BLACK(RIGHT(sibling));
rotate_left(parent, grandparent,
rootp);
child = *rootp;
}
} else {
sibling = LEFT(parent);
if (IS_RED(sibling)) {
MAKE_BLACK(sibling);
MAKE_RED(parent);
rotate_right(parent, grandparent,
rootp);
sibling = LEFT(parent);
}
if (IS_BLACK(LEFT(sibling)) &&
IS_BLACK(RIGHT(sibling))) {
MAKE_RED(sibling);
child = parent;
} else {
if (IS_BLACK(LEFT(sibling))) {
MAKE_BLACK(RIGHT(sibling));
MAKE_RED(sibling);
rotate_left(sibling,
grandparent,
rootp);
sibling = LEFT(parent);
}
COLOR(sibling) = COLOR(parent);
MAKE_BLACK(parent);
MAKE_BLACK(LEFT(sibling));
rotate_right(parent, grandparent,
rootp);
child = *rootp;
}
}
}
if (IS_RED(child))
MAKE_BLACK(child);
}
}
/*
* This should only be used on the root of a tree, because no color fixup
* is done at all.
*
* NOTE: No root pointer maintenance is done, because the function is only
* used for two cases:
* + deleting everything DOWN from a node that is itself being deleted, and
* + deleting the entire tree of trees from dns_rbt_destroy.
* In each case, the root pointer is no longer relevant, so there
* is no need for a root parameter to this function.
*
* If the function is ever intended to be used to delete something where
* a pointer needs to be told that this tree no longer exists,
* this function would need to adjusted accordingly.
*/
static void
dns_rbt_deletetree(dns_rbt_t *rbt, dns_rbtnode_t *node) {
REQUIRE(VALID_RBT(rbt));
if (node == NULL)
return;
if (LEFT(node) != NULL)
dns_rbt_deletetree(rbt, LEFT(node));
if (RIGHT(node) != NULL)
dns_rbt_deletetree(rbt, RIGHT(node));
if (DOWN(node) != NULL)
dns_rbt_deletetree(rbt, DOWN(node));
if (DATA(node) != NULL && rbt->data_deleter != NULL)
rbt->data_deleter(DATA(node), rbt->deleter_arg);
isc_mem_put(rbt->mctx, node, NODE_SIZE(node));
}
static void
dns_rbt_indent(int depth) {
int i;
for (i = 0; i < depth; i++)
putchar('\t');
}
static void
dns_rbt_printnodename(dns_rbtnode_t *node) {
char *buffer[255];
isc_buffer_t target;
isc_region_t r;
dns_name_t name;
dns_offsets_t offsets;
r.length = NAMELEN(node);
r.base = NAME(node);
dns_name_init(&name, offsets);
dns_name_fromregion(&name, &r);
isc_buffer_init(&target, buffer, 255, ISC_BUFFERTYPE_TEXT);
/*
* ISC_FALSE means absolute names have the final dot added.
*/
dns_name_totext(&name, ISC_FALSE, &target);
printf("%.*s", (int)target.used, (char *)target.base);
}
static void
dns_rbt_printtree(dns_rbtnode_t *root, dns_rbtnode_t *parent, int depth) {
dns_rbt_indent(depth);
if (root != NULL) {
dns_rbt_printnodename(root);
printf(" (%s", IS_RED(root) ? "RED" : "black");
if (parent) {
printf(" from ");
dns_rbt_printnodename(parent);
}
printf(")\n");
depth++;
if (DOWN(root)) {
dns_rbt_indent(depth);
printf("++ BEG down from ");
dns_rbt_printnodename(root);
printf("\n");
dns_rbt_printtree(DOWN(root), NULL, depth);
dns_rbt_indent(depth);
printf("-- END down from ");
dns_rbt_printnodename(root);
printf("\n");
}
if (IS_RED(root) && IS_RED(LEFT(root)))
printf("** Red/Red color violation on left\n");
dns_rbt_printtree(LEFT(root), root, depth);
if (IS_RED(root) && IS_RED(RIGHT(root)))
printf("** Red/Red color violation on right\n");
dns_rbt_printtree(RIGHT(root), root, depth);
} else
printf("NULL\n");
}
void
dns_rbt_printall(dns_rbt_t *rbt) {
REQUIRE(VALID_RBT(rbt));
dns_rbt_printtree(rbt->root, NULL, 0);
}
/*
* Chain Functions
*/
void
dns_rbtnodechain_init(dns_rbtnodechain_t *chain, isc_mem_t *mctx) {
/*
* Initialize 'chain'.
*/
REQUIRE(chain != NULL);
chain->mctx = mctx;
chain->end = NULL;
chain->ancestors = chain->ancestor_block;
chain->ancestor_count = 0;
chain->ancestor_maxitems = DNS_RBT_ANCESTORBLOCK;
chain->level_count = 0;
chain->level_matches = 0;
chain->magic = CHAIN_MAGIC;
}
dns_result_t
dns_rbtnodechain_current(dns_rbtnodechain_t *chain, dns_name_t *name,
dns_name_t *origin, dns_rbtnode_t **node) {
dns_result_t result = DNS_R_SUCCESS;
REQUIRE(VALID_CHAIN(chain));
if (node != NULL)
*node = chain->end;
if (chain->end == NULL)
return (DNS_R_NOTFOUND);
if (name != NULL) {
NODENAME(chain->end, name);
if (chain->level_count == 0) {
/*
* Eliminate the root name, except when name is ".".
*/
if (FAST_COUNTLABELS(name) > 1) {
INSIST(FAST_ISABSOLUTE(name));
/*
* XXX EVIL. But what _should_ I do?
*/
name->labels--;
name->length--;
name->attributes &= ~DNS_NAMEATTR_ABSOLUTE;
}
}
}
if (origin != NULL) {
if (chain->level_count > 0)
result = chain_name(chain, origin, ISC_FALSE);
else
result = dns_name_concatenate(NULL, dns_rootname,
origin, NULL);
}
return (result);
}
dns_result_t
dns_rbtnodechain_prev(dns_rbtnodechain_t *chain, dns_name_t *name,
dns_name_t *origin)
{
dns_rbtnode_t *current, *previous, *predecessor;
dns_result_t result = DNS_R_SUCCESS;
isc_boolean_t new_origin = ISC_FALSE;
REQUIRE(VALID_CHAIN(chain) && chain->end != NULL);
predecessor = NULL;
current = chain->end;
if (LEFT(current) != NULL) {
ADD_ANCESTOR(chain, current);
current = LEFT(current);
while (RIGHT(current) != NULL) {
ADD_ANCESTOR(chain, current);
current = RIGHT(current);
}
predecessor = current;
} else {
while (chain->ancestors[chain->ancestor_count - 1] != NULL) {
INSIST(chain->ancestor_count > 1);
previous = current;
current = chain->ancestors[--chain->ancestor_count];
if (RIGHT(current) == previous) {
predecessor = current;
break;
}
}
}
if (predecessor != NULL) {
if (DOWN(predecessor) != NULL) {
/*
* The predecessor is really down at least one level.
* Go down and as far right as possible, and repeat
* as long as the rightmost node has a down pointer.
*/
do {
/*
* XXX DCL Need to do something about origins
* here. See whether to go down, and if so
* whether it is truly what Bob calls a
* new origin.
*/
ADD_ANCESTOR(chain, NULL);
ADD_LEVEL(chain, predecessor);
predecessor = DOWN(predecessor);
/* XXX DCL duplicated from above; clever
* way to unduplicate? */
while (RIGHT(predecessor) != NULL) {
ADD_ANCESTOR(chain, predecessor);
predecessor = RIGHT(predecessor);
}
} while (DOWN(predecessor) != NULL);
/* XXX DCL probably needs work on the concept */
if (origin != NULL)
new_origin = ISC_TRUE;
}
} else if (chain->level_count > 0) {
/*
* Got to the root of this level without having traversed
* any right links. Ascend the tree one level.
*/
INSIST(chain->level_count > 0 &&
chain->ancestor_count > 0);
predecessor = chain->levels[--chain->level_count];
chain->ancestor_count--;
/* XXX DCL probably needs work on the concept */
/*
* Don't declare an origin change when the new origin is "."
* at the top level tree, because "." is declared as the origin
* for the second level tree.
*/
if (origin &&
(chain->level_count > 0 || OFFSETLEN(predecessor) > 1))
new_origin = ISC_TRUE;
}
if (predecessor != NULL) {
chain->end = predecessor;
if (new_origin) {
result = dns_rbtnodechain_current(chain, name, origin,
NULL);
if (result == DNS_R_SUCCESS)
result = DNS_R_NEWORIGIN;
} else
result = dns_rbtnodechain_current(chain, name, NULL,
NULL);
} else
result = DNS_R_NOMORE;
return (result);
}
dns_result_t
dns_rbtnodechain_next(dns_rbtnodechain_t *chain, dns_name_t *name,
dns_name_t *origin)
{
dns_rbtnode_t *current, *previous, *successor;
dns_result_t result = DNS_R_SUCCESS;
isc_boolean_t new_origin = ISC_FALSE;
REQUIRE(VALID_CHAIN(chain) && chain->end != NULL);
successor = NULL;
current = chain->end;
if (DOWN(current) != NULL) {
/*
* Don't declare an origin change when the new origin is "."
* at the second level tree, because "." is already declared
* as the origin for the top level tree.
*/
if (chain->level_count > 0 ||
OFFSETLEN(current) > 1)
new_origin = ISC_TRUE;
ADD_ANCESTOR(chain, NULL);
ADD_LEVEL(chain, current);
current = DOWN(current);
while (LEFT(current) != NULL) {
ADD_ANCESTOR(chain, current);
current = LEFT(current);
}
successor = current;
} else if (RIGHT(current) == NULL) {
/*
* The successor is up, either in this level or a previous one.
* Head back toward the root of the tree, looking for any path
* that was via a left link; the successor is the node that has
* that left link. In the event the root of the level is
* reached without having traversed any left links, ascend one
* level and look for either a right link off the point of
* ascent, or search for a left link upward again, repeating
* ascents until either case is true.
*/
do {
while (chain->ancestors[chain->ancestor_count - 1] !=
NULL) {
INSIST(chain->ancestor_count > 1);
previous = current;
current =
chain->ancestors[--chain->ancestor_count];
if (LEFT(current) == previous) {
successor = current;
break;
}
}
if (successor == NULL && chain->level_count > 0) {
/*
* Reached the root without having traversed
* any left pointers, so this level is done.
*/
INSIST(chain->ancestor_count > 0);
current = chain->levels[--chain->level_count];
chain->ancestor_count--;
new_origin = ISC_TRUE;
if (RIGHT(current) != NULL)
break;
}
} while (successor == NULL && chain->level_count > 0);
}
if (successor == NULL && RIGHT(current) != NULL) {
ADD_ANCESTOR(chain, current);
current = RIGHT(current);
while (LEFT(current) != NULL) {
ADD_ANCESTOR(chain, current);
current = LEFT(current);
}
successor = current;
}
if (successor != NULL) {
chain->end = successor;
/*
* It is not necessary to use dns_rbtnodechain_next like
* the other functions because this function will never
* find a node in the topmost level. This is because the
* root level will never be more than one name, and everything
* in the megatree is a successor to that node, down at
* the second level or below.
*/
NODENAME(chain->end, name);
if (new_origin) {
if (origin != NULL)
result = chain_name(chain, origin, ISC_FALSE);
if (result == DNS_R_SUCCESS)
result = DNS_R_NEWORIGIN;
} else
result = DNS_R_SUCCESS;
} else
result = DNS_R_NOMORE;
return (result);
}
dns_result_t
dns_rbtnodechain_first(dns_rbtnodechain_t *chain, dns_rbt_t *rbt,
dns_name_t *name, dns_name_t *origin)
{
dns_result_t result;
REQUIRE(name != NULL && origin != NULL);
REQUIRE(VALID_RBT(rbt));
REQUIRE(VALID_CHAIN(chain));
dns_rbtnodechain_reset(chain);
ADD_ANCESTOR(chain, NULL);
chain->end = rbt->root;
result = dns_rbtnodechain_current(chain, name, origin, NULL);
if (result == DNS_R_SUCCESS)
result = DNS_R_NEWORIGIN;
return (result);
}
dns_result_t
dns_rbtnodechain_last(dns_rbtnodechain_t *chain, dns_rbt_t *rbt,
dns_name_t *name, dns_name_t *origin)
{
dns_result_t result;
REQUIRE(name != NULL && origin != NULL);
REQUIRE(VALID_RBT(rbt));
REQUIRE(VALID_CHAIN(chain));
dns_rbtnodechain_reset(chain);
ADD_ANCESTOR(chain, NULL);
result = move_chain_to_last(chain, rbt->root);
if (result != DNS_R_SUCCESS)
return (result);
result = dns_rbtnodechain_current(chain, name, origin, NULL);
if (result == DNS_R_SUCCESS)
result = DNS_R_NEWORIGIN;
return (result);
}
void
dns_rbtnodechain_reset(dns_rbtnodechain_t *chain) {
/*
* Free any dynamic storage associated with 'chain', and then
* reinitialize 'chain'.
*/
REQUIRE(VALID_CHAIN(chain));
put_ancestor_mem(chain);
chain->end = NULL;
chain->ancestors = chain->ancestor_block;
chain->ancestor_count = 0;
chain->ancestor_maxitems = DNS_RBT_ANCESTORBLOCK;
chain->level_count = 0;
chain->level_matches = 0;
}
void
dns_rbtnodechain_invalidate(dns_rbtnodechain_t *chain) {
/*
* Free any dynamic storage associated with 'chain', and then
* invalidate 'chain'.
*/
dns_rbtnodechain_reset(chain);
chain->magic = 0;
}
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