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freebsd-skq/lib/dns/rbt.c
dougb 6c8226d7d6 Vendor import of BIND 9.4.3
2008-12-23 18:35:21 +00:00

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/*
* Copyright (C) 2004, 2005, 2008 Internet Systems Consortium, Inc. ("ISC")
* Copyright (C) 1999-2003 Internet Software Consortium.
*
* Permission to use, copy, modify, and/or 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 ISC DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS. IN NO EVENT SHALL ISC 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 1.128.18.10 2008/03/31 13:32:59 fdupont Exp $ */
/*! \file */
/* Principal Authors: DCL */
#include <config.h>
#include <isc/mem.h>
#include <isc/platform.h>
#include <isc/print.h>
#include <isc/refcount.h>
#include <isc/string.h>
#include <isc/util.h>
/*%
* This define is so dns/name.h (included by dns/fixedname.h) uses more
* efficient macro calls instead of functions for a few operations.
*/
#define DNS_NAME_USEINLINE 1
#include <dns/fixedname.h>
#include <dns/rbt.h>
#include <dns/result.h>
#define RBT_MAGIC ISC_MAGIC('R', 'B', 'T', '+')
#define VALID_RBT(rbt) ISC_MAGIC_VALID(rbt, RBT_MAGIC)
/*
* XXXDCL Since parent pointers were added in again, I could remove all of the
* chain junk, and replace with dns_rbt_firstnode, _previousnode, _nextnode,
* _lastnode. This would involve pretty major change to the API.
*/
#define CHAIN_MAGIC ISC_MAGIC('0', '-', '0', '-')
#define VALID_CHAIN(chain) ISC_MAGIC_VALID(chain, CHAIN_MAGIC)
#define RBT_HASH_SIZE 64
#ifdef RBT_MEM_TEST
#undef RBT_HASH_SIZE
#define RBT_HASH_SIZE 2 /*%< To give the reallocation code a workout. */
#endif
struct dns_rbt {
unsigned int magic;
isc_mem_t * mctx;
dns_rbtnode_t * root;
void (*data_deleter)(void *, void *);
void * deleter_arg;
unsigned int nodecount;
unsigned int hashsize;
dns_rbtnode_t ** hashtable;
};
#define RED 0
#define BLACK 1
/*%
* Elements of the rbtnode structure.
*/
#define PARENT(node) ((node)->parent)
#define LEFT(node) ((node)->left)
#define RIGHT(node) ((node)->right)
#define DOWN(node) ((node)->down)
#define DATA(node) ((node)->data)
#define HASHNEXT(node) ((node)->hashnext)
#define HASHVAL(node) ((node)->hashval)
#define COLOR(node) ((node)->color)
#define NAMELEN(node) ((node)->namelen)
#define OFFSETLEN(node) ((node)->offsetlen)
#define ATTRS(node) ((node)->attributes)
#define PADBYTES(node) ((node)->padbytes)
#define IS_ROOT(node) ISC_TF((node)->is_root == 1)
#define FINDCALLBACK(node) ISC_TF((node)->find_callback == 1)
/*%
* Structure elements from the rbtdb.c, not
* used as part of the rbt.c algorithms.
*/
#define DIRTY(node) ((node)->dirty)
#define WILD(node) ((node)->wild)
#define LOCKNUM(node) ((node)->locknum)
/*%
* 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.
*
* The "ancestors" member of chains were removed, with their job now
* being wholy handled by parent pointers (which didn't exist, because
* of memory concerns, when chains were first implemented).
*/
#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)
#ifdef DNS_RBT_USEHASH
static isc_result_t
inithash(dns_rbt_t *rbt);
#endif
#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);
}
static void dns_rbt_printnodename(dns_rbtnode_t *node);
#endif
static inline dns_rbtnode_t *
find_up(dns_rbtnode_t *node) {
dns_rbtnode_t *root;
/*
* Return the node in the level above the argument node that points
* to the level the argument node is in. If the argument node is in
* the top level, the return value is NULL.
*/
for (root = node; ! IS_ROOT(root); root = PARENT(root))
; /* Nothing. */
return (PARENT(root));
}
/*
* Forward declarations.
*/
static isc_result_t
create_node(isc_mem_t *mctx, dns_name_t *name, dns_rbtnode_t **nodep);
#ifdef DNS_RBT_USEHASH
static inline void
hash_node(dns_rbt_t *rbt, dns_rbtnode_t *node, dns_name_t *name);
static inline void
unhash_node(dns_rbt_t *rbt, dns_rbtnode_t *node);
#else
#define hash_node(rbt, node, name) (ISC_R_SUCCESS)
#define unhash_node(rbt, node)
#endif
static inline void
rotate_left(dns_rbtnode_t *node, dns_rbtnode_t **rootp);
static inline void
rotate_right(dns_rbtnode_t *node, dns_rbtnode_t **rootp);
static void
dns_rbt_addonlevel(dns_rbtnode_t *node, dns_rbtnode_t *current, int order,
dns_rbtnode_t **rootp);
static void
dns_rbt_deletefromlevel(dns_rbtnode_t *delete, dns_rbtnode_t **rootp);
static isc_result_t
dns_rbt_deletetree(dns_rbt_t *rbt, dns_rbtnode_t *node);
static void
dns_rbt_deletetreeflat(dns_rbt_t *rbt, unsigned int quantum,
dns_rbtnode_t **nodep);
/*
* Initialize a red/black tree of trees.
*/
isc_result_t
dns_rbt_create(isc_mem_t *mctx, void (*deleter)(void *, void *),
void *deleter_arg, dns_rbt_t **rbtp)
{
#ifdef DNS_RBT_USEHASH
isc_result_t result;
#endif
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 (ISC_R_NOMEMORY);
rbt->mctx = mctx;
rbt->data_deleter = deleter;
rbt->deleter_arg = deleter_arg;
rbt->root = NULL;
rbt->nodecount = 0;
rbt->hashtable = NULL;
rbt->hashsize = 0;
#ifdef DNS_RBT_USEHASH
result = inithash(rbt);
if (result != ISC_R_SUCCESS) {
isc_mem_put(mctx, rbt, sizeof(*rbt));
return (result);
}
#endif
rbt->magic = RBT_MAGIC;
*rbtp = rbt;
return (ISC_R_SUCCESS);
}
/*
* Deallocate a red/black tree of trees.
*/
void
dns_rbt_destroy(dns_rbt_t **rbtp) {
RUNTIME_CHECK(dns_rbt_destroy2(rbtp, 0) == ISC_R_SUCCESS);
}
isc_result_t
dns_rbt_destroy2(dns_rbt_t **rbtp, unsigned int quantum) {
dns_rbt_t *rbt;
REQUIRE(rbtp != NULL && VALID_RBT(*rbtp));
rbt = *rbtp;
dns_rbt_deletetreeflat(rbt, quantum, &rbt->root);
if (rbt->root != NULL)
return (ISC_R_QUOTA);
INSIST(rbt->nodecount == 0);
if (rbt->hashtable != NULL)
isc_mem_put(rbt->mctx, rbt->hashtable,
rbt->hashsize * sizeof(dns_rbtnode_t *));
rbt->magic = 0;
isc_mem_put(rbt->mctx, rbt, sizeof(*rbt));
*rbtp = NULL;
return (ISC_R_SUCCESS);
}
unsigned int
dns_rbt_nodecount(dns_rbt_t *rbt) {
REQUIRE(VALID_RBT(rbt));
return (rbt->nodecount);
}
static inline isc_result_t
chain_name(dns_rbtnodechain_t *chain, dns_name_t *name,
isc_boolean_t include_chain_end)
{
dns_name_t nodename;
isc_result_t result = ISC_R_SUCCESS;
int i;
dns_name_init(&nodename, NULL);
if (include_chain_end && chain->end != NULL) {
NODENAME(chain->end, &nodename);
result = dns_name_copy(&nodename, name, NULL);
if (result != ISC_R_SUCCESS)
return (result);
} else
dns_name_reset(name);
for (i = (int)chain->level_count - 1; i >= 0; i--) {
NODENAME(chain->levels[i], &nodename);
result = dns_name_concatenate(name, &nodename, name, NULL);
if (result != ISC_R_SUCCESS)
return (result);
}
return (result);
}
static inline isc_result_t
move_chain_to_last(dns_rbtnodechain_t *chain, dns_rbtnode_t *node) {
do {
/*
* 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)
node = RIGHT(node);
if (DOWN(node) == NULL)
break;
ADD_LEVEL(chain, node);
node = DOWN(node);
} while (1);
chain->end = node;
return (ISC_R_SUCCESS);
}
/*
* Add 'name' to tree, initializing its data pointer with 'data'.
*/
isc_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, *new_name, current_name, *prefix, *suffix;
dns_fixedname_t fixedcopy, fixedprefix, fixedsuffix, fnewname;
dns_offsets_t current_offsets;
dns_namereln_t compared;
isc_result_t result = ISC_R_SUCCESS;
dns_rbtnodechain_t chain;
unsigned int common_labels;
unsigned int nlabels, hlabels;
int order;
REQUIRE(VALID_RBT(rbt));
REQUIRE(dns_name_isabsolute(name));
REQUIRE(nodep != NULL && *nodep == NULL);
/*
* Create a copy of the name so the original name structure is
* not modified.
*/
dns_fixedname_init(&fixedcopy);
add_name = dns_fixedname_name(&fixedcopy);
dns_name_clone(name, add_name);
if (rbt->root == NULL) {
result = create_node(rbt->mctx, add_name, &new_current);
if (result == ISC_R_SUCCESS) {
rbt->nodecount++;
new_current->is_root = 1;
rbt->root = new_current;
*nodep = new_current;
hash_node(rbt, new_current, name);
}
return (result);
}
dns_rbtnodechain_init(&chain, rbt->mctx);
dns_fixedname_init(&fixedprefix);
dns_fixedname_init(&fixedsuffix);
prefix = dns_fixedname_name(&fixedprefix);
suffix = dns_fixedname_name(&fixedsuffix);
root = &rbt->root;
INSIST(IS_ROOT(*root));
parent = NULL;
current = NULL;
child = *root;
dns_name_init(&current_name, current_offsets);
dns_fixedname_init(&fnewname);
new_name = dns_fixedname_name(&fnewname);
nlabels = dns_name_countlabels(name);
hlabels = 0;
do {
current = child;
NODENAME(current, &current_name);
compared = dns_name_fullcompare(add_name, &current_name,
&order, &common_labels);
if (compared == dns_namereln_equal) {
*nodep = current;
result = ISC_R_EXISTS;
break;
}
if (compared == dns_namereln_none) {
if (order < 0) {
parent = current;
child = LEFT(current);
} else if (order > 0) {
parent = current;
child = RIGHT(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.
*/
hlabels += common_labels;
if (compared == dns_namereln_subdomain) {
/*
* All of the existing labels are in common,
* so the new name is in a subtree.
* Whack off the common labels for the
* not-in-common part to be searched for
* in the next level.
*/
dns_name_split(add_name, common_labels,
add_name, NULL);
/*
* Follow the down pointer (possibly NULL).
*/
root = &DOWN(current);
INSIST(*root == NULL ||
(IS_ROOT(*root) &&
PARENT(*root) == current));
parent = NULL;
child = DOWN(current);
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);
/*
* Ensure the number of levels in the tree
* does not exceed the number of logical
* levels allowed by DNSSEC.
*
* XXXDCL need a better error result?
*
* XXXDCL Since chain ancestors were removed,
* no longer used by dns_rbt_addonlevel(),
* this is the only real use of chains in the
* function. It could be done instead with
* a simple integer variable, but I am pressed
* for time.
*/
if (chain.level_count ==
(sizeof(chain.levels) /
sizeof(*chain.levels))) {
result = ISC_R_NOSPACE;
break;
}
/*
* Split the name into two parts, a prefix
* which is the not-in-common parts of the
* two names and a suffix that is the common
* parts of them.
*/
dns_name_split(&current_name, common_labels,
prefix, suffix);
result = create_node(rbt->mctx, suffix,
&new_current);
if (result != ISC_R_SUCCESS)
break;
/*
* Reproduce the tree attributes of the
* current node.
*/
new_current->is_root = current->is_root;
PARENT(new_current) = PARENT(current);
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 (LEFT(new_current) != NULL)
PARENT(LEFT(new_current)) =
new_current;
if (RIGHT(new_current) != NULL)
PARENT(RIGHT(new_current)) =
new_current;
if (*root == current)
*root = new_current;
NAMELEN(current) = prefix->length;
OFFSETLEN(current) = prefix->labels;
memcpy(OFFSETS(current), prefix->offsets,
prefix->labels);
PADBYTES(current) +=
(current_name.length - prefix->length) +
(current_name.labels - prefix->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.
*/
current->is_root = 1;
PARENT(current) = new_current;
DOWN(new_current) = current;
root = &DOWN(new_current);
ADD_LEVEL(&chain, new_current);
LEFT(current) = NULL;
RIGHT(current) = NULL;
MAKE_BLACK(current);
ATTRS(current) &= ~DNS_NAMEATTR_ABSOLUTE;
rbt->nodecount++;
dns_name_getlabelsequence(name,
nlabels - hlabels,
hlabels, new_name);
hash_node(rbt, new_current, new_name);
if (common_labels ==
dns_name_countlabels(add_name)) {
/*
* The name has been added by pushing
* the not-in-common parts down to
* a new level.
*/
*nodep = new_current;
return (ISC_R_SUCCESS);
} else {
/*
* The current node has no data,
* because it is just a placeholder.
* Its data pointer is already NULL
* from create_node()), so there's
* nothing more to do to it.
*/
/*
* The not-in-common parts of the new
* name will be inserted into the new
* level following this loop (unless
* result != ISC_R_SUCCESS, which
* is tested after the loop ends).
*/
dns_name_split(add_name, common_labels,
add_name, NULL);
break;
}
}
}
} while (child != NULL);
if (result == ISC_R_SUCCESS)
result = create_node(rbt->mctx, add_name, &new_current);
if (result == ISC_R_SUCCESS) {
dns_rbt_addonlevel(new_current, current, order, root);
rbt->nodecount++;
*nodep = new_current;
hash_node(rbt, new_current, name);
}
return (result);
}
/*
* Add a name to the tree of trees, associating it with some data.
*/
isc_result_t
dns_rbt_addname(dns_rbt_t *rbt, dns_name_t *name, void *data) {
isc_result_t result;
dns_rbtnode_t *node;
REQUIRE(VALID_RBT(rbt));
REQUIRE(dns_name_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 == ISC_R_SUCCESS ||
(result == ISC_R_EXISTS && DATA(node) == NULL)) {
DATA(node) = data;
result = ISC_R_SUCCESS;
}
return (result);
}
/*
* Find the node for "name" in the tree of trees.
*/
isc_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,
unsigned int options, dns_rbtfindcallback_t callback,
void *callback_arg)
{
dns_rbtnode_t *current, *last_compared, *current_root;
dns_rbtnodechain_t localchain;
dns_name_t *search_name, current_name, *callback_name;
dns_fixedname_t fixedcallbackname, fixedsearchname;
dns_namereln_t compared;
isc_result_t result, saved_result;
unsigned int common_labels;
unsigned int hlabels = 0;
int order;
REQUIRE(VALID_RBT(rbt));
REQUIRE(dns_name_isabsolute(name));
REQUIRE(node != NULL && *node == NULL);
REQUIRE((options & (DNS_RBTFIND_NOEXACT | DNS_RBTFIND_NOPREDECESSOR))
!= (DNS_RBTFIND_NOEXACT | DNS_RBTFIND_NOPREDECESSOR));
/*
* 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) {
options |= DNS_RBTFIND_NOPREDECESSOR;
chain = &localchain;
dns_rbtnodechain_init(chain, rbt->mctx);
} else
dns_rbtnodechain_reset(chain);
if (rbt->root == NULL)
return (ISC_R_NOTFOUND);
else {
/*
* Appease GCC about variables it incorrectly thinks are
* possibly used uninitialized.
*/
compared = dns_namereln_none;
last_compared = NULL;
}
dns_fixedname_init(&fixedcallbackname);
callback_name = dns_fixedname_name(&fixedcallbackname);
/*
* search_name is the name segment being sought in each tree level.
* By using a fixedname, the search_name will definitely have offsets
* for use by any splitting.
* By using dns_name_clone, no name data should be copied thanks to
* the lack of bitstring labels.
*/
dns_fixedname_init(&fixedsearchname);
search_name = dns_fixedname_name(&fixedsearchname);
dns_name_clone(name, search_name);
dns_name_init(&current_name, NULL);
saved_result = ISC_R_SUCCESS;
current = rbt->root;
current_root = rbt->root;
while (current != NULL) {
NODENAME(current, &current_name);
compared = dns_name_fullcompare(search_name, &current_name,
&order, &common_labels);
last_compared = current;
if (compared == dns_namereln_equal)
break;
if (compared == dns_namereln_none) {
#ifdef DNS_RBT_USEHASH
dns_name_t hash_name;
dns_rbtnode_t *hnode;
dns_rbtnode_t *up_current;
unsigned int nlabels;
unsigned int tlabels = 1;
unsigned int hash;
/*
* If there is no hash table, hashing can't be done.
*/
if (rbt->hashtable == NULL)
goto nohash;
/*
* The case of current != current_root, that
* means a left or right pointer was followed,
* only happens when the algorithm fell through to
* the traditional binary search because of a
* bitstring label. Since we dropped the bitstring
* support, this should not happen.
*/
INSIST(current == current_root);
nlabels = dns_name_countlabels(search_name);
/*
* current_root is the root of the current level, so
* it's parent is the same as it's "up" pointer.
*/
up_current = PARENT(current_root);
dns_name_init(&hash_name, NULL);
hashagain:
/*
* Hash includes tail.
*/
dns_name_getlabelsequence(name,
nlabels - tlabels,
hlabels + tlabels,
&hash_name);
hash = dns_name_fullhash(&hash_name, ISC_FALSE);
dns_name_getlabelsequence(search_name,
nlabels - tlabels,
tlabels, &hash_name);
for (hnode = rbt->hashtable[hash % rbt->hashsize];
hnode != NULL;
hnode = hnode->hashnext)
{
dns_name_t hnode_name;
if (hash != HASHVAL(hnode))
continue;
if (find_up(hnode) != up_current)
continue;
dns_name_init(&hnode_name, NULL);
NODENAME(hnode, &hnode_name);
if (dns_name_equal(&hnode_name, &hash_name))
break;
}
if (hnode != NULL) {
current = hnode;
/*
* This is an optimization. If hashing found
* the right node, the next call to
* dns_name_fullcompare() would obviously
* return _equal or _subdomain. Determine
* which of those would be the case by
* checking if the full name was hashed. Then
* make it look like dns_name_fullcompare
* was called and jump to the right place.
*/
if (tlabels == nlabels) {
compared = dns_namereln_equal;
break;
} else {
common_labels = tlabels;
compared = dns_namereln_subdomain;
goto subdomain;
}
}
if (tlabels++ < nlabels)
goto hashagain;
/*
* All of the labels have been tried against the hash
* table. Since we dropped the support of bitstring
* labels, the name isn't in the table.
*/
current = NULL;
continue;
nohash:
#endif /* DNS_RBT_USEHASH */
/*
* 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) {
subdomain:
/*
* Whack off the current node's common parts
* for the name to search in the next level.
*/
dns_name_split(search_name, common_labels,
search_name, NULL);
hlabels += common_labels;
/*
* This might be the closest enclosing name.
*/
if (DATA(current) != NULL ||
(options & DNS_RBTFIND_EMPTYDATA) != 0)
*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_LEVEL(chain, current);
/*
* 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 &&
FINDCALLBACK(current)) {
result = chain_name(chain,
callback_name,
ISC_FALSE);
if (result != ISC_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);
current_root = 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.
*/
INSIST(compared == dns_namereln_commonancestor
|| compared == dns_namereln_contains);
current = NULL;
}
}
}
/*
* If current is not NULL, NOEXACT is not disallowing exact matches,
* and either the node has data or an empty node is ok, return
* ISC_R_SUCCESS to indicate an exact match.
*/
if (current != NULL && (options & DNS_RBTFIND_NOEXACT) == 0 &&
(DATA(current) != NULL ||
(options & DNS_RBTFIND_EMPTYDATA) != 0)) {
/*
* Found an exact match.
*/
chain->end = current;
chain->level_matches = chain->level_count;
if (foundname != NULL)
result = chain_name(chain, foundname, ISC_TRUE);
else
result = ISC_R_SUCCESS;
if (result == ISC_R_SUCCESS) {
*node = current;
result = saved_result;
} else
*node = NULL;
} else {
/*
* Did not find an exact match (or did not want one).
*/
if (*node != NULL) {
/*
* ... but found a partially matching superdomain.
* Unwind the chain to the partial match node
* to set level_matches to the level above the node,
* and then to derive the name.
*
* chain->level_count is guaranteed to be at least 1
* here because by definition of finding a superdomain,
* the chain is pointed to at least the first subtree.
*/
chain->level_matches = chain->level_count - 1;
while (chain->levels[chain->level_matches] != *node) {
INSIST(chain->level_matches > 0);
chain->level_matches--;
}
if (foundname != NULL) {
unsigned int saved_count = chain->level_count;
chain->level_count = chain->level_matches + 1;
result = chain_name(chain, foundname,
ISC_FALSE);
chain->level_count = saved_count;
} else
result = ISC_R_SUCCESS;
if (result == ISC_R_SUCCESS)
result = DNS_R_PARTIALMATCH;
} else
result = ISC_R_NOTFOUND;
if (current != NULL) {
/*
* There was an exact match but either
* DNS_RBTFIND_NOEXACT was set, or
* DNS_RBTFIND_EMPTYDATA was set and the node had no
* data. A policy decision was made to set the
* chain to the exact match, but this is subject
* to change if it becomes apparent that something
* else would be more useful. It is important that
* this case is handled here, because the predecessor
* setting code below assumes the match was not exact.
*/
INSIST(((options & DNS_RBTFIND_NOEXACT) != 0) ||
((options & DNS_RBTFIND_EMPTYDATA) == 0 &&
DATA(current) == NULL));
chain->end = current;
} else if ((options & DNS_RBTFIND_NOPREDECESSOR) != 0) {
/*
* Ensure the chain points nowhere.
*/
chain->end = NULL;
} else {
/*
* Since there was no exact match, the chain argument
* needs to be pointed at the DNSSEC predecessor of
* the search name.
*/
if (compared == dns_namereln_subdomain) {
/*
* 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);
INSIST(chain->level_matches <
chain->level_count);
chain->end =
chain->levels[--chain->level_count];
} else {
isc_result_t result2;
/*
* Point current to the node that stopped
* the search.
*
* With the hashing modification that has been
* added to the algorithm, the stop node of a
* standard binary search is not known. So it
* has to be found. There is probably a more
* clever way of doing this.
*
* The assignment of current to NULL when
* the relationship is *not* dns_namereln_none,
* even though it later gets set to the same
* last_compared anyway, is simply to not push
* the while loop in one more level of
* indentation.
*/
if (compared == dns_namereln_none)
current = last_compared;
else
current = NULL;
while (current != NULL) {
NODENAME(current, &current_name);
compared = dns_name_fullcompare(
search_name,
&current_name,
&order,
&common_labels);
last_compared = current;
/*
* Standard binary search movement.
*/
if (order < 0)
current = LEFT(current);
else
current = RIGHT(current);
}
current = last_compared;
/*
* 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_LEVEL(chain, current);
result2 =
move_chain_to_last(chain,
DOWN(current));
if (result2 != ISC_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 == ISC_R_SUCCESS ||
result2 == DNS_R_NEWORIGIN)
; /* Nothing. */
else if (result2 == ISC_R_NOMORE)
/*
* There is no predecessor.
*/
dns_rbtnodechain_reset(chain);
else
result = result2;
}
}
}
}
ENSURE(*node == NULL || DNS_RBTNODE_VALID(*node));
return (result);
}
/*
* Get the data pointer associated with 'name'.
*/
isc_result_t
dns_rbt_findname(dns_rbt_t *rbt, dns_name_t *name, unsigned int options,
dns_name_t *foundname, void **data) {
dns_rbtnode_t *node = NULL;
isc_result_t result;
REQUIRE(data != NULL && *data == NULL);
result = dns_rbt_findnode(rbt, name, foundname, &node, NULL,
options, NULL, NULL);
if (node != NULL &&
(DATA(node) != NULL || (options & DNS_RBTFIND_EMPTYDATA) != 0))
*data = DATA(node);
else
result = ISC_R_NOTFOUND;
return (result);
}
/*
* Delete a name from the tree of trees.
*/
isc_result_t
dns_rbt_deletename(dns_rbt_t *rbt, dns_name_t *name, isc_boolean_t recurse) {
dns_rbtnode_t *node = NULL;
isc_result_t result;
REQUIRE(VALID_RBT(rbt));
REQUIRE(dns_name_isabsolute(name));
/*
* First, find the node.
*
* 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.
*/
result = dns_rbt_findnode(rbt, name, NULL, &node, NULL,
DNS_RBTFIND_NOOPTIONS, NULL, NULL);
if (result == ISC_R_SUCCESS) {
if (DATA(node) != NULL)
result = dns_rbt_deletenode(rbt, node, recurse);
else
result = ISC_R_NOTFOUND;
} else if (result == DNS_R_PARTIALMATCH)
result = ISC_R_NOTFOUND;
return (result);
}
/*
* Remove a node from the tree of trees.
*
* NOTE WELL: deletion is *not* symmetric with addition; that is, reversing
* a sequence of additions to be deletions will not generally get the
* tree back to the state it started in. For example, if the addition
* of "b.c" caused the node "a.b.c" to be split, pushing "a" to its own level,
* then the subsequent deletion of "b.c" will not cause "a" to be pulled up,
* restoring "a.b.c". The RBT *used* to do this kind of rejoining, but it
* turned out to be a bad idea because it could corrupt an active nodechain
* that had "b.c" as one of its levels -- and the RBT has no idea what
* nodechains are in use by callers, so it can't even *try* to helpfully
* fix them up (which would probably be doomed to failure anyway).
*
* Similarly, it is possible to leave the tree in a state where a supposedly
* deleted node still exists. The first case of this is obvious; take
* the tree which has "b.c" on one level, pointing to "a". Now deleted "b.c".
* It was just established in the previous paragraph why we can't pull "a"
* back up to its parent level. But what happens when "a" then gets deleted?
* "b.c" is left hanging around without data or children. This condition
* is actually pretty easy to detect, but ... should it really be removed?
* Is a chain pointing to it? An iterator? Who knows! (Note that the
* references structure member cannot be looked at because it is private to
* rbtdb.) This is ugly and makes me unhappy, but after hours of trying to
* make it more aesthetically proper and getting nowhere, this is the way it
* is going to stay until such time as it proves to be a *real* problem.
*
* Finally, for reference, note that the original routine that did node
* joining was called join_nodes(). It has been excised, living now only
* in the CVS history, but comments have been left behind that point to it just
* in case someone wants to muck with this some more.
*
* The one positive aspect of all of this is that joining used to have a
* case where it might fail. Without trying to join, now this function always
* succeeds. It still returns isc_result_t, though, so the API wouldn't change.
*/
isc_result_t
dns_rbt_deletenode(dns_rbt_t *rbt, dns_rbtnode_t *node, isc_boolean_t recurse)
{
dns_rbtnode_t *parent;
REQUIRE(VALID_RBT(rbt));
REQUIRE(DNS_RBTNODE_VALID(node));
if (DOWN(node) != NULL) {
if (recurse)
RUNTIME_CHECK(dns_rbt_deletetree(rbt, DOWN(node))
== ISC_R_SUCCESS);
else {
if (DATA(node) != NULL && rbt->data_deleter != NULL)
rbt->data_deleter(DATA(node),
rbt->deleter_arg);
DATA(node) = NULL;
/*
* Since there is at least one node below this one and
* no recursion was requested, the deletion is
* complete. The down node from this node might be all
* by itself on a single level, so join_nodes() could
* be used to collapse the tree (with all the caveats
* of the comment at the start of this function).
*/
return (ISC_R_SUCCESS);
}
}
/*
* Note the node that points to the level of the node that is being
* deleted. If the deleted node is the top level, parent will be set
* to NULL.
*/
parent = find_up(node);
/*
* 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(node, parent == NULL ? &rbt->root :
&DOWN(parent));
if (DATA(node) != NULL && rbt->data_deleter != NULL)
rbt->data_deleter(DATA(node), rbt->deleter_arg);
unhash_node(rbt, node);
#if DNS_RBT_USEMAGIC
node->magic = 0;
#endif
dns_rbtnode_refdestroy(node);
isc_mem_put(rbt->mctx, node, NODE_SIZE(node));
rbt->nodecount--;
/*
* There are now two special cases that can exist that would
* not have existed if the tree had been created using only
* the names that now exist in it. (This is all related to
* join_nodes() as described in this function's introductory comment.)
* Both cases exist when the deleted node's parent (the node
* that pointed to the deleted node's level) is not null but
* it has no data: parent != NULL && DATA(parent) == NULL.
*
* The first case is that the deleted node was the last on its level:
* DOWN(parent) == NULL. This case can only exist if the parent was
* previously deleted -- and so now, apparently, the parent should go
* away. That can't be done though because there might be external
* references to it, such as through a nodechain.
*
* The other case also involves a parent with no data, but with the
* deleted node being the next-to-last node instead of the last:
* LEFT(DOWN(parent)) == NULL && RIGHT(DOWN(parent)) == NULL.
* Presumably now the remaining node on the level should be joined
* with the parent, but it's already been described why that can't be
* done.
*/
/*
* This function never fails.
*/
return (ISC_R_SUCCESS);
}
void
dns_rbt_namefromnode(dns_rbtnode_t *node, dns_name_t *name) {
REQUIRE(DNS_RBTNODE_VALID(node));
REQUIRE(name != NULL);
REQUIRE(name->offsets == NULL);
NODENAME(node, name);
}
isc_result_t
dns_rbt_fullnamefromnode(dns_rbtnode_t *node, dns_name_t *name) {
dns_name_t current;
isc_result_t result;
REQUIRE(DNS_RBTNODE_VALID(node));
REQUIRE(name != NULL);
REQUIRE(name->buffer != NULL);
dns_name_init(&current, NULL);
dns_name_reset(name);
do {
INSIST(node != NULL);
NODENAME(node, &current);
result = dns_name_concatenate(name, &current, name, NULL);
if (result != ISC_R_SUCCESS)
break;
node = find_up(node);
} while (! dns_name_isabsolute(name));
return (result);
}
char *
dns_rbt_formatnodename(dns_rbtnode_t *node, char *printname, unsigned int size)
{
dns_fixedname_t fixedname;
dns_name_t *name;
isc_result_t result;
REQUIRE(DNS_RBTNODE_VALID(node));
REQUIRE(printname != NULL);
dns_fixedname_init(&fixedname);
name = dns_fixedname_name(&fixedname);
result = dns_rbt_fullnamefromnode(node, name);
if (result == ISC_R_SUCCESS)
dns_name_format(name, printname, size);
else
snprintf(printname, size, "<error building name: %s>",
dns_result_totext(result));
return (printname);
}
static isc_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 = dns_name_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 (ISC_R_NOMEMORY);
node->is_root = 0;
PARENT(node) = NULL;
RIGHT(node) = NULL;
LEFT(node) = NULL;
DOWN(node) = NULL;
DATA(node) = NULL;
#ifdef DNS_RBT_USEHASH
HASHNEXT(node) = NULL;
HASHVAL(node) = 0;
#endif
LOCKNUM(node) = 0;
WILD(node) = 0;
DIRTY(node) = 0;
dns_rbtnode_refinit(node, 0);
node->find_callback = 0;
MAKE_BLACK(node);
/*
* 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);
#if DNS_RBT_USEMAGIC
node->magic = DNS_RBTNODE_MAGIC;
#endif
*nodep = node;
return (ISC_R_SUCCESS);
}
#ifdef DNS_RBT_USEHASH
static inline void
hash_add_node(dns_rbt_t *rbt, dns_rbtnode_t *node, dns_name_t *name) {
unsigned int hash;
HASHVAL(node) = dns_name_fullhash(name, ISC_FALSE);
hash = HASHVAL(node) % rbt->hashsize;
HASHNEXT(node) = rbt->hashtable[hash];
rbt->hashtable[hash] = node;
}
static isc_result_t
inithash(dns_rbt_t *rbt) {
unsigned int bytes;
rbt->hashsize = RBT_HASH_SIZE;
bytes = rbt->hashsize * sizeof(dns_rbtnode_t *);
rbt->hashtable = isc_mem_get(rbt->mctx, bytes);
if (rbt->hashtable == NULL)
return (ISC_R_NOMEMORY);
memset(rbt->hashtable, 0, bytes);
return (ISC_R_SUCCESS);
}
static void
rehash(dns_rbt_t *rbt) {
unsigned int oldsize;
dns_rbtnode_t **oldtable;
dns_rbtnode_t *node;
unsigned int hash;
unsigned int i;
oldsize = rbt->hashsize;
oldtable = rbt->hashtable;
rbt->hashsize *= 2 + 1;
rbt->hashtable = isc_mem_get(rbt->mctx,
rbt->hashsize * sizeof(dns_rbtnode_t *));
if (rbt->hashtable == NULL) {
rbt->hashtable = oldtable;
rbt->hashsize = oldsize;
return;
}
for (i = 0; i < rbt->hashsize; i++)
rbt->hashtable[i] = NULL;
for (i = 0; i < oldsize; i++) {
node = oldtable[i];
while (node != NULL) {
hash = HASHVAL(node) % rbt->hashsize;
oldtable[i] = HASHNEXT(node);
HASHNEXT(node) = rbt->hashtable[hash];
rbt->hashtable[hash] = node;
node = oldtable[i];
}
}
isc_mem_put(rbt->mctx, oldtable, oldsize * sizeof(dns_rbtnode_t *));
}
static inline void
hash_node(dns_rbt_t *rbt, dns_rbtnode_t *node, dns_name_t *name) {
REQUIRE(DNS_RBTNODE_VALID(node));
if (rbt->nodecount >= (rbt->hashsize *3))
rehash(rbt);
hash_add_node(rbt, node, name);
}
static inline void
unhash_node(dns_rbt_t *rbt, dns_rbtnode_t *node) {
unsigned int bucket;
dns_rbtnode_t *bucket_node;
REQUIRE(DNS_RBTNODE_VALID(node));
if (rbt->hashtable != NULL) {
bucket = HASHVAL(node) % rbt->hashsize;
bucket_node = rbt->hashtable[bucket];
if (bucket_node == node)
rbt->hashtable[bucket] = HASHNEXT(node);
else {
while (HASHNEXT(bucket_node) != node) {
INSIST(HASHNEXT(bucket_node) != NULL);
bucket_node = HASHNEXT(bucket_node);
}
HASHNEXT(bucket_node) = HASHNEXT(node);
}
}
}
#endif /* DNS_RBT_USEHASH */
static inline void
rotate_left(dns_rbtnode_t *node, dns_rbtnode_t **rootp) {
dns_rbtnode_t *child;
REQUIRE(DNS_RBTNODE_VALID(node));
REQUIRE(rootp != NULL);
child = RIGHT(node);
INSIST(child != NULL);
RIGHT(node) = LEFT(child);
if (LEFT(child) != NULL)
PARENT(LEFT(child)) = node;
LEFT(child) = node;
if (child != NULL)
PARENT(child) = PARENT(node);
if (IS_ROOT(node)) {
*rootp = child;
child->is_root = 1;
node->is_root = 0;
} else {
if (LEFT(PARENT(node)) == node)
LEFT(PARENT(node)) = child;
else
RIGHT(PARENT(node)) = child;
}
PARENT(node) = child;
}
static inline void
rotate_right(dns_rbtnode_t *node, dns_rbtnode_t **rootp) {
dns_rbtnode_t *child;
REQUIRE(DNS_RBTNODE_VALID(node));
REQUIRE(rootp != NULL);
child = LEFT(node);
INSIST(child != NULL);
LEFT(node) = RIGHT(child);
if (RIGHT(child) != NULL)
PARENT(RIGHT(child)) = node;
RIGHT(child) = node;
if (child != NULL)
PARENT(child) = PARENT(node);
if (IS_ROOT(node)) {
*rootp = child;
child->is_root = 1;
node->is_root = 0;
} else {
if (LEFT(PARENT(node)) == node)
LEFT(PARENT(node)) = child;
else
RIGHT(PARENT(node)) = child;
}
PARENT(node) = 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_rbtnode_t *child, *root, *parent, *grandparent;
dns_name_t add_name, current_name;
dns_offsets_t add_offsets, current_offsets;
REQUIRE(rootp != NULL);
REQUIRE(DNS_RBTNODE_VALID(node) && LEFT(node) == NULL &&
RIGHT(node) == NULL);
REQUIRE(current != NULL);
root = *rootp;
if (root == NULL) {
/*
* First node of a level.
*/
MAKE_BLACK(node);
node->is_root = 1;
PARENT(node) = current;
*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) {
INSIST(LEFT(current) == NULL);
LEFT(current) = node;
} else {
INSIST(RIGHT(current) == NULL);
RIGHT(current) = node;
}
INSIST(PARENT(node) == NULL);
PARENT(node) = current;
MAKE_RED(node);
while (node != root && IS_RED(PARENT(node))) {
/*
* XXXDCL could do away with separate parent and grandparent
* variables. They are vestiges of the days before parent
* pointers. However, they make the code a little clearer.
*/
parent = PARENT(node);
grandparent = PARENT(parent);
if (parent == LEFT(grandparent)) {
child = RIGHT(grandparent);
if (child != NULL && IS_RED(child)) {
MAKE_BLACK(parent);
MAKE_BLACK(child);
MAKE_RED(grandparent);
node = grandparent;
} else {
if (node == RIGHT(parent)) {
rotate_left(parent, &root);
node = parent;
parent = PARENT(node);
grandparent = PARENT(parent);
}
MAKE_BLACK(parent);
MAKE_RED(grandparent);
rotate_right(grandparent, &root);
}
} else {
child = LEFT(grandparent);
if (child != NULL && IS_RED(child)) {
MAKE_BLACK(parent);
MAKE_BLACK(child);
MAKE_RED(grandparent);
node = grandparent;
} else {
if (node == LEFT(parent)) {
rotate_right(parent, &root);
node = parent;
parent = PARENT(node);
grandparent = PARENT(parent);
}
MAKE_BLACK(parent);
MAKE_RED(grandparent);
rotate_left(grandparent, &root);
}
}
}
MAKE_BLACK(root);
ENSURE(IS_ROOT(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.
*/
static void
dns_rbt_deletefromlevel(dns_rbtnode_t *delete, dns_rbtnode_t **rootp) {
dns_rbtnode_t *child, *sibling, *parent;
dns_rbtnode_t *successor;
REQUIRE(delete != NULL);
/*
* Verify that the parent history is (apparently) correct.
*/
INSIST((IS_ROOT(delete) && *rootp == delete) ||
(! IS_ROOT(delete) &&
(LEFT(PARENT(delete)) == delete ||
RIGHT(PARENT(delete)) == delete)));
child = NULL;
if (LEFT(delete) == NULL) {
if (RIGHT(delete) == NULL) {
if (IS_ROOT(delete)) {
/*
* 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.
*/
successor = RIGHT(delete);
while (LEFT(successor) != NULL)
successor = LEFT(successor);
/*
* The successor cannot possibly have a left child;
* if there is any child, it is on the right.
*/
if (RIGHT(successor) != NULL)
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 be unchanged.
*/
/*
* First, put the successor in the tree location of the
* node to be deleted. Save its existing tree pointer
* information, which will be needed when linking up
* delete to the successor's old location.
*/
memcpy(tmp, successor, sizeof(dns_rbtnode_t));
if (IS_ROOT(delete)) {
*rootp = successor;
successor->is_root = ISC_TRUE;
delete->is_root = ISC_FALSE;
} else
if (LEFT(PARENT(delete)) == delete)
LEFT(PARENT(delete)) = successor;
else
RIGHT(PARENT(delete)) = successor;
PARENT(successor) = PARENT(delete);
LEFT(successor) = LEFT(delete);
RIGHT(successor) = RIGHT(delete);
COLOR(successor) = COLOR(delete);
if (LEFT(successor) != NULL)
PARENT(LEFT(successor)) = successor;
if (RIGHT(successor) != successor)
PARENT(RIGHT(successor)) = successor;
/*
* Now relink the node to be deleted into the
* successor's previous tree location. PARENT(tmp)
* is the successor's original parent.
*/
INSIST(! IS_ROOT(delete));
if (PARENT(tmp) == delete) {
/*
* Node being deleted was successor's parent.
*/
RIGHT(successor) = delete;
PARENT(delete) = successor;
} else {
LEFT(PARENT(tmp)) = delete;
PARENT(delete) = PARENT(tmp);
}
/*
* Original location of successor node has no left.
*/
LEFT(delete) = NULL;
RIGHT(delete) = RIGHT(tmp);
COLOR(delete) = COLOR(tmp);
}
/*
* Remove the node by removing the links from its parent.
*/
if (! IS_ROOT(delete)) {
if (LEFT(PARENT(delete)) == delete)
LEFT(PARENT(delete)) = child;
else
RIGHT(PARENT(delete)) = child;
if (child != NULL)
PARENT(child) = PARENT(delete);
} else {
/*
* This is the root being deleted, and at this point
* it is known to have just one child.
*/
*rootp = child;
child->is_root = 1;
PARENT(child) = PARENT(delete);
}
/*
* Fix color violations.
*/
if (IS_BLACK(delete)) {
parent = PARENT(delete);
while (child != *rootp && IS_BLACK(child)) {
INSIST(child == NULL || ! IS_ROOT(child));
if (LEFT(parent) == child) {
sibling = RIGHT(parent);
if (IS_RED(sibling)) {
MAKE_BLACK(sibling);
MAKE_RED(parent);
rotate_left(parent, 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, rootp);
sibling = RIGHT(parent);
}
COLOR(sibling) = COLOR(parent);
MAKE_BLACK(parent);
MAKE_BLACK(RIGHT(sibling));
rotate_left(parent, rootp);
child = *rootp;
}
} else {
/*
* Child is parent's right child.
* Everything is doen the same as above,
* except mirrored.
*/
sibling = LEFT(parent);
if (IS_RED(sibling)) {
MAKE_BLACK(sibling);
MAKE_RED(parent);
rotate_right(parent, 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, rootp);
sibling = LEFT(parent);
}
COLOR(sibling) = COLOR(parent);
MAKE_BLACK(parent);
MAKE_BLACK(LEFT(sibling));
rotate_right(parent, rootp);
child = *rootp;
}
}
parent = PARENT(child);
}
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 isc_result_t
dns_rbt_deletetree(dns_rbt_t *rbt, dns_rbtnode_t *node) {
isc_result_t result = ISC_R_SUCCESS;
REQUIRE(VALID_RBT(rbt));
if (node == NULL)
return (result);
if (LEFT(node) != NULL) {
result = dns_rbt_deletetree(rbt, LEFT(node));
if (result != ISC_R_SUCCESS)
goto done;
LEFT(node) = NULL;
}
if (RIGHT(node) != NULL) {
result = dns_rbt_deletetree(rbt, RIGHT(node));
if (result != ISC_R_SUCCESS)
goto done;
RIGHT(node) = NULL;
}
if (DOWN(node) != NULL) {
result = dns_rbt_deletetree(rbt, DOWN(node));
if (result != ISC_R_SUCCESS)
goto done;
DOWN(node) = NULL;
}
done:
if (result != ISC_R_SUCCESS)
return (result);
if (DATA(node) != NULL && rbt->data_deleter != NULL)
rbt->data_deleter(DATA(node), rbt->deleter_arg);
unhash_node(rbt, node);
#if DNS_RBT_USEMAGIC
node->magic = 0;
#endif
isc_mem_put(rbt->mctx, node, NODE_SIZE(node));
rbt->nodecount--;
return (result);
}
static void
dns_rbt_deletetreeflat(dns_rbt_t *rbt, unsigned int quantum,
dns_rbtnode_t **nodep)
{
dns_rbtnode_t *parent;
dns_rbtnode_t *node = *nodep;
REQUIRE(VALID_RBT(rbt));
again:
if (node == NULL) {
*nodep = NULL;
return;
}
traverse:
if (LEFT(node) != NULL) {
node = LEFT(node);
goto traverse;
}
if (DOWN(node) != NULL) {
node = DOWN(node);
goto traverse;
}
if (DATA(node) != NULL && rbt->data_deleter != NULL)
rbt->data_deleter(DATA(node), rbt->deleter_arg);
/*
* Note: we don't call unhash_node() here as we are destroying
* the complete rbt tree.
*/
#if DNS_RBT_USEMAGIC
node->magic = 0;
#endif
parent = PARENT(node);
if (RIGHT(node) != NULL)
PARENT(RIGHT(node)) = parent;
if (parent != NULL) {
if (LEFT(parent) == node)
LEFT(parent) = RIGHT(node);
else if (DOWN(parent) == node)
DOWN(parent) = RIGHT(node);
} else
parent = RIGHT(node);
isc_mem_put(rbt->mctx, node, NODE_SIZE(node));
rbt->nodecount--;
node = parent;
if (quantum != 0 && --quantum == 0) {
*nodep = node;
return;
}
goto again;
}
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) {
isc_region_t r;
dns_name_t name;
char buffer[DNS_NAME_FORMATSIZE];
dns_offsets_t offsets;
r.length = NAMELEN(node);
r.base = NAME(node);
dns_name_init(&name, offsets);
dns_name_fromregion(&name, &r);
dns_name_format(&name, buffer, sizeof(buffer));
printf("%s", buffer);
}
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);
}
if ((! IS_ROOT(root) && PARENT(root) != parent) ||
( IS_ROOT(root) && depth > 0 &&
DOWN(PARENT(root)) != root)) {
printf(" (BAD parent pointer! -> ");
if (PARENT(root) != NULL)
dns_rbt_printnodename(PARENT(root));
else
printf("NULL");
printf(")");
}
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->level_count = 0;
chain->level_matches = 0;
memset(chain->levels, 0, sizeof(chain->levels));
chain->magic = CHAIN_MAGIC;
}
isc_result_t
dns_rbtnodechain_current(dns_rbtnodechain_t *chain, dns_name_t *name,
dns_name_t *origin, dns_rbtnode_t **node)
{
isc_result_t result = ISC_R_SUCCESS;
REQUIRE(VALID_CHAIN(chain));
if (node != NULL)
*node = chain->end;
if (chain->end == NULL)
return (ISC_R_NOTFOUND);
if (name != NULL) {
NODENAME(chain->end, name);
if (chain->level_count == 0) {
/*
* Names in the top level tree are all absolute.
* Always make 'name' relative.
*/
INSIST(dns_name_isabsolute(name));
/*
* This is cheaper than dns_name_getlabelsequence().
*/
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_copy(dns_rootname, origin, NULL);
}
return (result);
}
isc_result_t
dns_rbtnodechain_prev(dns_rbtnodechain_t *chain, dns_name_t *name,
dns_name_t *origin)
{
dns_rbtnode_t *current, *previous, *predecessor;
isc_result_t result = ISC_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) {
/*
* Moving left one then right as far as possible is the
* previous node, at least for this level.
*/
current = LEFT(current);
while (RIGHT(current) != NULL)
current = RIGHT(current);
predecessor = current;
} else {
/*
* No left links, so move toward the root. If at any point on
* the way there the link from parent to child is a right
* link, then the parent is the previous node, at least
* for this level.
*/
while (! IS_ROOT(current)) {
previous = current;
current = PARENT(current);
if (RIGHT(current) == previous) {
predecessor = current;
break;
}
}
}
if (predecessor != NULL) {
/*
* Found a predecessor node in this level. It might not
* really be the predecessor, however.
*/
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_LEVEL(chain, predecessor);
predecessor = DOWN(predecessor);
/* XXX DCL duplicated from above; clever
* way to unduplicate? */
while (RIGHT(predecessor) != NULL)
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) {
/*
* Dang, didn't find a predecessor in this level.
* Got to the root of this level without having traversed
* any right links. Ascend the tree one level; the
* node that points to this tree is the predecessor.
*/
INSIST(chain->level_count > 0 && IS_ROOT(current));
predecessor = chain->levels[--chain->level_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 != NULL &&
(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 == ISC_R_SUCCESS)
result = DNS_R_NEWORIGIN;
} else
result = dns_rbtnodechain_current(chain, name, NULL,
NULL);
} else
result = ISC_R_NOMORE;
return (result);
}
isc_result_t
dns_rbtnodechain_next(dns_rbtnodechain_t *chain, dns_name_t *name,
dns_name_t *origin)
{
dns_rbtnode_t *current, *previous, *successor;
isc_result_t result = ISC_R_SUCCESS;
isc_boolean_t new_origin = ISC_FALSE;
REQUIRE(VALID_CHAIN(chain) && chain->end != NULL);
successor = NULL;
current = chain->end;
/*
* If there is a level below this node, the next node is the leftmost
* node of the next level.
*/
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_LEVEL(chain, current);
current = DOWN(current);
while (LEFT(current) != NULL)
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 (! IS_ROOT(current)) {
previous = current;
current = PARENT(current);
if (LEFT(current) == previous) {
successor = current;
break;
}
}
if (successor == NULL) {
/*
* Reached the root without having traversed
* any left pointers, so this level is done.
*/
if (chain->level_count == 0)
break;
current = chain->levels[--chain->level_count];
new_origin = ISC_TRUE;
if (RIGHT(current) != NULL)
break;
}
} while (successor == NULL);
}
if (successor == NULL && RIGHT(current) != NULL) {
current = RIGHT(current);
while (LEFT(current) != NULL)
current = LEFT(current);
successor = current;
}
if (successor != NULL) {
chain->end = successor;
/*
* It is not necessary to use dns_rbtnodechain_current 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.
*/
if (name != NULL)
NODENAME(chain->end, name);
if (new_origin) {
if (origin != NULL)
result = chain_name(chain, origin, ISC_FALSE);
if (result == ISC_R_SUCCESS)
result = DNS_R_NEWORIGIN;
} else
result = ISC_R_SUCCESS;
} else
result = ISC_R_NOMORE;
return (result);
}
isc_result_t
dns_rbtnodechain_first(dns_rbtnodechain_t *chain, dns_rbt_t *rbt,
dns_name_t *name, dns_name_t *origin)
{
isc_result_t result;
REQUIRE(VALID_RBT(rbt));
REQUIRE(VALID_CHAIN(chain));
dns_rbtnodechain_reset(chain);
chain->end = rbt->root;
result = dns_rbtnodechain_current(chain, name, origin, NULL);
if (result == ISC_R_SUCCESS)
result = DNS_R_NEWORIGIN;
return (result);
}
isc_result_t
dns_rbtnodechain_last(dns_rbtnodechain_t *chain, dns_rbt_t *rbt,
dns_name_t *name, dns_name_t *origin)
{
isc_result_t result;
REQUIRE(VALID_RBT(rbt));
REQUIRE(VALID_CHAIN(chain));
dns_rbtnodechain_reset(chain);
result = move_chain_to_last(chain, rbt->root);
if (result != ISC_R_SUCCESS)
return (result);
result = dns_rbtnodechain_current(chain, name, origin, NULL);
if (result == ISC_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));
chain->end = NULL;
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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