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Diffstat (limited to 'lib/dns/rbt.c')
| -rw-r--r-- | lib/dns/rbt.c | 2657 |
1 files changed, 2657 insertions, 0 deletions
diff --git a/lib/dns/rbt.c b/lib/dns/rbt.c new file mode 100644 index 0000000..112591e --- /dev/null +++ b/lib/dns/rbt.c @@ -0,0 +1,2657 @@ +/* + * Copyright (C) 2004, 2005, 2007, 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 1.142 2008/09/24 02:46:22 marka 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/log.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(¤t_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, ¤t_name); + compared = dns_name_fullcompare(add_name, ¤t_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(¤t_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; + new_current->nsec3 = current->nsec3; + 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(¤t_name, NULL); + + saved_result = ISC_R_SUCCESS; + current = rbt->root; + current_root = rbt->root; + + while (current != NULL) { + NODENAME(current, ¤t_name); + compared = dns_name_fullcompare(search_name, ¤t_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, ¤t_name); + compared = dns_name_fullcompare( + search_name, + ¤t_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(¤t, NULL); + dns_name_reset(name); + + do { + INSIST(node != NULL); + + NODENAME(node, ¤t); + + result = dns_name_concatenate(name, ¤t, 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, ®ion); + 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 + + ISC_LINK_INIT(node, deadlink); + + LOCKNUM(node) = 0; + WILD(node) = 0; + DIRTY(node) = 0; + dns_rbtnode_refinit(node, 0); + node->find_callback = 0; + node->nsec3 = 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(¤t_name, current_offsets); + NODENAME(current, ¤t_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_down(dns_rbtnodechain_t *chain, dns_name_t *name, + dns_name_t *origin) +{ + dns_rbtnode_t *current, *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_LEVEL(chain, current); + current = DOWN(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_nextflat(dns_rbtnodechain_t *chain, dns_name_t *name) { + dns_rbtnode_t *current, *previous, *successor; + isc_result_t result = ISC_R_SUCCESS; + + REQUIRE(VALID_CHAIN(chain) && chain->end != NULL); + + successor = NULL; + + current = chain->end; + + if (RIGHT(current) == NULL) { + while (! IS_ROOT(current)) { + previous = current; + current = PARENT(current); + + if (LEFT(current) == previous) { + successor = current; + break; + } + } + } else { + current = RIGHT(current); + + while (LEFT(current) != NULL) + current = LEFT(current); + + successor = current; + } + + if (successor != NULL) { + chain->end = successor; + + if (name != NULL) + NODENAME(chain->end, name); + + result = ISC_R_SUCCESS; + } 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; +} |