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bind9/lib/dns/rbt.c
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David Lawrence d7197f2ab0 Add DNS_RBTFIND_NOPREDECESSOR to specify that the predecessor searching code 
of dns_rbt_findnode should be skipped.  Nothing external uses it yet, but
when the chain option is NULL, this option is set internally as predecessor
searching is irrelevant.  (It was skipped before now, but via a different
mechanism.)

Add DNS_RBTFIND_NOOPTIONS to make it clear what the options parameter of
dns_rbt_find* is when no options are passed, and use it in dns_rbt_deletename.

REQUIRE that DNS_RBTFIND_NOEXACT and DNS_RBTFIND_NOPREDECESSOR are mutually
exclusive to dns_rbt_findnode.
2000-04-24 21:18:16 +00:00

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/*
* Copyright (C) 1999, 2000 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 1.75 2000/04/24 21:18:16 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)
/*
* XXXDCL could remove all of the chain junk, and replace with
* dns_rbt_firstnode, _previousnode, _nextnode, _lastnode. pretty
* major change to the API.
*/
#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 IS_ROOT(node) ((node)->is_root)
#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 FINDCALLBACK(node) ((node)->find_callback)
#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)
/*
* 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 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) != ISC_R_SUCCESS) { \
dns_rbtnodechain_invalidate(chain); \
return (ISC_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);
}
static void dns_rbt_printnodename(dns_rbtnode_t *node);
#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 isc_result_t create_node(isc_mem_t *mctx,
dns_name_t *name, dns_rbtnode_t **nodep);
static isc_result_t join_nodes(dns_rbt_t *rbt, dns_rbtnode_t *node);
static inline isc_result_t get_ancestor_mem(dns_rbtnodechain_t *chain);
static inline void put_ancestor_mem(dns_rbtnodechain_t *chain);
/*
* XXXDCL could ditch parent and root arguments to rotate_*, since
* now with parent pointers they could figure out the needed pointers
* themselves. this would slightly simplify dns_rbt_{addon,deletefrom}level.
*/
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);
static void dns_rbt_deletetree(dns_rbt_t *rbt, dns_rbtnode_t *node);
/*
* 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)
{
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->magic = RBT_MAGIC;
*rbtp = rbt;
return (ISC_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 isc_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 (ISC_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 (ISC_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 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;
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 != ISC_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 != ISC_R_SUCCESS)
break;
}
if (result == ISC_R_SUCCESS &&
include_chain_end && chain->end != NULL) {
NODENAME(chain->end, &nodename);
result = dns_name_concatenate(&nodename, name, name, NULL);
}
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) {
ADD_ANCESTOR(chain, node);
node = RIGHT(node);
}
if (DOWN(node) == NULL)
break;
ADD_ANCESTOR(chain, NULL);
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, current_name, *prefix, *suffix;
dns_fixedname_t fixedcopy, fixedprefix, fixedsuffix;
dns_offsets_t current_offsets;
dns_namereln_t compared;
isc_result_t result = ISC_R_SUCCESS;
dns_rbtnodechain_t chain;
unsigned int common_labels, common_bits, add_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. The name data needs to be modifiable when
* a node is split on a bitstring label.
*/
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) {
IS_ROOT(new_current) = ISC_TRUE;
rbt->root = new_current;
*nodep = new_current;
}
return (result);
}
dns_rbtnodechain_init(&chain, rbt->mctx);
ADD_ANCESTOR(&chain, NULL);
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);
do {
current = child;
INSIST((IS_ROOT(current) &&
chain.ancestors[chain.ancestor_count - 1] == NULL) ||
(! IS_ROOT(current) &&
chain.ancestors[chain.ancestor_count - 1] ==
PARENT(current)));
NODENAME(current, &current_name);
compared = dns_name_fullcompare(add_name, &current_name,
&order,
&common_labels, &common_bits);
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);
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.
*/
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.
*/
result = dns_name_split(add_name,
common_labels,
common_bits,
add_name, NULL);
if (result != ISC_R_SUCCESS)
break;
/*
* Follow the down pointer (possibly NULL).
*/
root = &DOWN(current);
INSIST(*root == NULL ||
(IS_ROOT(*root) &&
PARENT(*root) == 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);
/*
* 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))) {
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.
*/
result = dns_name_split(&current_name,
common_labels,
common_bits,
prefix, suffix);
if (result == ISC_R_SUCCESS)
result = create_node(rbt->mctx, suffix,
&new_current);
if (result != ISC_R_SUCCESS)
break;
/*
* Reproduce the tree attributes of the
* current node.
*/
IS_ROOT(new_current) = IS_ROOT(current);
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;
/*
* Now make 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.
*
* 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.
*
* When bitstring labels are involved, things
* are just a tad more complicated (aren't
* they always?) because the splitting
* has shifted the bits that this name needs,
* as well as adjusted the bit count.
* So there are convolutions to deal with it.
* There are compromises here between
* abstraction and efficiency.
*/
if (common_bits > 0) {
dns_label_t label;
dns_name_getlabel(prefix,
FAST_COUNTLABELS(&current_name) -
common_labels,
&label);
INSIST(dns_label_type(&label) ==
dns_labeltype_bitstring);
memcpy(NAME(current) +
(label.base - prefix->ndata),
label.base,
label.length);
dns_name_getlabel(add_name,
FAST_COUNTLABELS(add_name) -
common_labels,
&label);
INSIST(dns_label_type(&label) ==
dns_labeltype_bitstring);
add_bits = dns_label_countbits(&label);
} else
add_bits = 0;
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.
*/
IS_ROOT(current) = ISC_TRUE;
PARENT(current) = new_current;
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 ==
FAST_COUNTLABELS(add_name) &&
common_bits == add_bits) {
/*
* 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 (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 but add it to
* the ancestor chain, because it will
* be the parent node of the new node.
*/
ADD_ANCESTOR(&chain, current);
/* 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).
*/
result = dns_name_split(add_name,
common_labels,
common_bits,
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, &chain);
*nodep = new_current;
}
put_ancestor_mem(&chain);
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(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 == 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;
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, common_bits;
int order;
REQUIRE(VALID_RBT(rbt));
REQUIRE(FAST_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);
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
* and a buffer for use by any splitting that happens in the middle
* of a bitstring label. By using dns_name_clone, no name data is
* copied unless a bitstring split occurs.
*/
dns_fixedname_init(&fixedsearchname);
search_name = dns_fixedname_name(&fixedsearchname);
dns_name_clone(name, search_name);
dns_name_init(&current_name, NULL);
ADD_ANCESTOR(chain, NULL);
saved_result = ISC_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) {
/*
* Whack off the current node's common parts
* for the name to search in the next level.
*/
result = dns_name_split(search_name,
common_labels,
common_bits,
search_name, NULL);
if (result != ISC_R_SUCCESS) {
dns_rbtnodechain_reset(chain);
return (result);
}
/*
* 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_ANCESTOR(chain, NULL);
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);
} 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);
ADD_ANCESTOR(chain, current);
current = NULL;
}
}
}
if (current != NULL && (options & DNS_RBTFIND_NOEXACT) == 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 DNS_RBTFIND_NOEXACT
* was set. 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);
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.
*
* 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);
INSIST(chain->level_matches <
chain->level_count);
chain->end =
chain->levels[--chain->level_count];
} else {
isc_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 != 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;
}
}
}
}
if (chain == &localchain)
put_ancestor_mem(chain);
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)
*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(FAST_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 and rejoin any levels, if possible.
*/
isc_result_t
dns_rbt_deletenode(dns_rbt_t *rbt, dns_rbtnode_t *node, isc_boolean_t recurse)
{
dns_rbtnode_t *parent, *root;
isc_result_t result;
REQUIRE(VALID_RBT(rbt));
REQUIRE(node != NULL);
if (DOWN(node) != NULL) {
if (recurse)
dns_rbt_deletetree(rbt, DOWN(node));
else {
if (rbt->data_deleter != NULL)
rbt->data_deleter(DATA(node),
rbt->deleter_arg);
DATA(node) = NULL;
if (LEFT(DOWN(node)) != NULL ||
RIGHT(DOWN(node)) != 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 (ISC_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.
*/
result = join_nodes(rbt, node);
return (result);
}
}
/*
* 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.
*/
for (root = node; ! IS_ROOT(root); root = PARENT(root))
; /* Nothing. */
parent = PARENT(root);
/*
* 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);
if (rbt->data_deleter != NULL)
rbt->data_deleter(DATA(node), rbt->deleter_arg);
isc_mem_put(rbt->mctx, node, NODE_SIZE(node));
/*
* 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, to the node that points to the level of the deleted node.
*/
node = parent;
if (node != NULL && DATA(node) == NULL &&
LEFT(DOWN(node)) == NULL && RIGHT(DOWN(node)) == NULL)
result = join_nodes(rbt, node);
else
result = ISC_R_SUCCESS;
return (result);
}
void
dns_rbt_namefromnode(dns_rbtnode_t *node, dns_name_t *name) {
REQUIRE(name->offsets == NULL);
NODENAME(node, name);
}
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 = 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 (ISC_R_NOMEMORY);
IS_ROOT(node) = ISC_FALSE;
PARENT(node) = NULL;
RIGHT(node) = NULL;
LEFT(node) = NULL;
DOWN(node) = NULL;
DATA(node) = NULL;
LOCK(node) = 0;
REFS(node) = 0;
WILD(node) = 0;
DIRTY(node) = 0;
FINDCALLBACK(node) = 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);
*nodep = node;
return (ISC_R_SUCCESS);
}
static isc_result_t
join_nodes(dns_rbt_t *rbt, dns_rbtnode_t *node) {
dns_rbtnode_t *down, *newnode;
isc_result_t result;
dns_fixedname_t fixed_newname;
dns_name_t *newname, prefix, suffix;
unsigned int newlength, oldlength;
REQUIRE(VALID_RBT(rbt));
REQUIRE(node != NULL);
REQUIRE(DATA(node) == NULL && DOWN(node) != NULL);
down = DOWN(node);
dns_name_init(&prefix, NULL);
dns_name_init(&suffix, NULL);
dns_fixedname_init(&fixed_newname);
NODENAME(down, &prefix);
NODENAME(node, &suffix);
newname = dns_fixedname_name(&fixed_newname);
result = dns_name_concatenate(&prefix, &suffix, newname, NULL);
if (result != ISC_R_SUCCESS)
return (result);
/*
* 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.
*/
newlength = newname->length + newname->labels;
oldlength = NAMELEN(down) + OFFSETLEN(down);
if (newlength > oldlength + PADBYTES(down))
result = create_node(rbt->mctx, newname, &newnode);
else {
memcpy(NAME(down), newname->ndata, newname->length);
PADBYTES(down) -= newlength - oldlength;
NAMELEN(down) = newname->length;
OFFSETLEN(down) = newname->labels;
memcpy(OFFSETS(down), newname->offsets, newname->labels);
ATTRS(down) = newname->attributes;
newnode = down;
result = ISC_R_SUCCESS;
}
if (result == ISC_R_SUCCESS) {
COLOR(newnode) = COLOR(node);
PARENT(newnode) = PARENT(node);
RIGHT(newnode) = RIGHT(node);
LEFT(newnode) = LEFT(node);
IS_ROOT(newnode) = IS_ROOT(node);
DOWN(newnode) = DOWN(down);
DATA(newnode) = DATA(down);
/*
* Fix the pointers to the original node.
*/
if (IS_ROOT(node))
if (PARENT(node) == NULL)
rbt->root = newnode;
else
DOWN(PARENT(node)) = newnode;
else
if (LEFT(PARENT(node)) == node)
LEFT(PARENT(node)) = newnode;
else
RIGHT(PARENT(node)) = newnode;
if (DOWN(down) != NULL)
PARENT(DOWN(down)) = newnode;
isc_mem_put(rbt->mctx, node, NODE_SIZE(node));
if (newnode != down)
isc_mem_put(rbt->mctx, down, NODE_SIZE(down));
}
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);
REQUIRE(IS_ROOT(node) ||
RIGHT(parent) == node || LEFT(parent) == node);
INSIST((! IS_ROOT(node) && PARENT(node) == parent) ||
( IS_ROOT(node) && parent == 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;
IS_ROOT(child) = ISC_TRUE;
IS_ROOT(node) = ISC_FALSE;
} else {
if (LEFT(parent) == node)
LEFT(parent) = child;
else
RIGHT(parent) = child;
}
PARENT(node) = 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);
REQUIRE(IS_ROOT(node) ||
RIGHT(parent) == node || LEFT(parent) == node);
INSIST((! IS_ROOT(node) && PARENT(node) == parent) ||
( IS_ROOT(node) && parent == 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;
IS_ROOT(child) = ISC_TRUE;
IS_ROOT(node) = ISC_FALSE;
} else {
if (LEFT(parent) == node)
LEFT(parent) = child;
else
RIGHT(parent) = 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_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);
root = *rootp;
if (root == NULL) {
/*
* First node of a level.
*/
MAKE_BLACK(node);
IS_ROOT(node) = ISC_TRUE;
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);
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);
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_rbt_t *rbt, dns_rbtnode_t *delete) {
dns_rbtnode_t *child, *sibling, *parent, *grandparent;
dns_rbtnode_t *successor, *root, **rootp;
REQUIRE(VALID_RBT(rbt));
REQUIRE(delete != NULL);
for (root = delete; ! IS_ROOT(root); root = PARENT(root))
; /* Nothing. */
if (PARENT(root) != NULL)
rootp = &DOWN(PARENT(root));
else
rootp = &rbt->root;
/*
* 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;
IS_ROOT(successor) = ISC_TRUE;
IS_ROOT(delete) = 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;
sibling = RIGHT(PARENT(delete));
} else {
RIGHT(PARENT(delete)) = child;
sibling = LEFT(PARENT(delete));
}
if (child != NULL)
PARENT(child) = PARENT(delete);
if (sibling != NULL)
PARENT(sibling) = PARENT(delete);
} else {
/*
* This is the root being deleted, and at this point
* it is known to have just one child.
*/
*rootp = child;
IS_ROOT(child) = ISC_TRUE;
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));
grandparent = parent->parent;
if (LEFT(parent) == child) {
sibling = RIGHT(parent);
if (IS_RED(sibling)) {
MAKE_BLACK(sibling);
MAKE_RED(parent);
rotate_left(parent, grandparent,
rootp);
/*
* Parent was reparented by the
* rotation, so the new grandparent
* needs to be noted. Grandpa is dead,
* long live grandpa.
*/
grandparent = sibling;
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, parent,
rootp);
sibling = RIGHT(parent);
}
COLOR(sibling) = COLOR(parent);
MAKE_BLACK(parent);
MAKE_BLACK(RIGHT(sibling));
rotate_left(parent, grandparent,
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, grandparent,
rootp);
/*
* Parent was reparented by the
* rotation, so the new grandparent
* needs to be noted. Grandma is dead,
* long live grandma.
*/
grandparent = sibling;
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, parent,
rootp);
sibling = LEFT(parent);
}
COLOR(sibling) = COLOR(parent);
MAKE_BLACK(parent);
MAKE_BLACK(LEFT(sibling));
rotate_right(parent, grandparent,
rootp);
child = *rootp;
}
}
parent = child->parent;
}
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);
}
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->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;
}
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) {
/*
* 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);
}
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) {
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 != 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 (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) {
/*
* Reached the root without having traversed
* any left pointers, so this level is done.
*/
if (chain->level_count == 0)
break;
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);
}
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_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);
ADD_ANCESTOR(chain, NULL);
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);
ADD_ANCESTOR(chain, NULL);
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));
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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