contrib/bind-9.5.2/lib/dns/rbt.c

   1 /*
   2  * Copyright (C) 2004, 2005, 2007-2009  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 1999-2003  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and/or distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
  10  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  11  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  12  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  13  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  14  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  15  * PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 /* $Id: rbt.c,v 1.138.36.5 2009/01/19 23:47:02 tbox Exp $ */
  19
  20 /*! \file */
  21
  22 /* Principal Authors: DCL */
  23
  24 #include <config.h>
  25
  26 #include <isc/mem.h>
  27 #include <isc/platform.h>
  28 #include <isc/print.h>
  29 #include <isc/refcount.h>
  30 #include <isc/string.h>
  31 #include <isc/util.h>
  32
  33 /*%
  34  * This define is so dns/name.h (included by dns/fixedname.h) uses more
  35  * efficient macro calls instead of functions for a few operations.
  36  */
  37 #define DNS_NAME_USEINLINE 1
  38
  39 #include <dns/fixedname.h>
  40 #include <dns/log.h>
  41 #include <dns/rbt.h>
  42 #include <dns/result.h>
  43
  44 #define RBT_MAGIC               ISC_MAGIC('R', 'B', 'T', '+')
  45 #define VALID_RBT(rbt)          ISC_MAGIC_VALID(rbt, RBT_MAGIC)
  46
  47 /*
  48  * XXXDCL Since parent pointers were added in again, I could remove all of the
  49  * chain junk, and replace with dns_rbt_firstnode, _previousnode, _nextnode,
  50  * _lastnode.  This would involve pretty major change to the API.
  51  */
  52 #define CHAIN_MAGIC             ISC_MAGIC('0', '-', '0', '-')
  53 #define VALID_CHAIN(chain)      ISC_MAGIC_VALID(chain, CHAIN_MAGIC)
  54
  55 #define RBT_HASH_SIZE           64
  56
  57 #ifdef RBT_MEM_TEST
  58 #undef RBT_HASH_SIZE
  59 #define RBT_HASH_SIZE 2 /*%< To give the reallocation code a workout. */
  60 #endif
  61
  62 struct dns_rbt {
  63         unsigned int            magic;
  64         isc_mem_t *             mctx;
  65         dns_rbtnode_t *         root;
  66         void                    (*data_deleter)(void *, void *);
  67         void *                  deleter_arg;
  68         unsigned int            nodecount;
  69         unsigned int            hashsize;
  70         dns_rbtnode_t **        hashtable;
  71 };
  72
  73 #define RED 0
  74 #define BLACK 1
  75
  76 /*%
  77  * Elements of the rbtnode structure.
  78  */
  79 #define PARENT(node)            ((node)->parent)
  80 #define LEFT(node)              ((node)->left)
  81 #define RIGHT(node)             ((node)->right)
  82 #define DOWN(node)              ((node)->down)
  83 #define DATA(node)              ((node)->data)
  84 #define HASHNEXT(node)          ((node)->hashnext)
  85 #define HASHVAL(node)           ((node)->hashval)
  86 #define COLOR(node)             ((node)->color)
  87 #define NAMELEN(node)           ((node)->namelen)
  88 #define OFFSETLEN(node)         ((node)->offsetlen)
  89 #define ATTRS(node)             ((node)->attributes)
  90 #define PADBYTES(node)          ((node)->padbytes)
  91 #define IS_ROOT(node)           ISC_TF((node)->is_root == 1)
  92 #define FINDCALLBACK(node)      ISC_TF((node)->find_callback == 1)
  93
  94 /*%
  95  * Structure elements from the rbtdb.c, not
  96  * used as part of the rbt.c algorithms.
  97  */
  98 #define DIRTY(node)     ((node)->dirty)
  99 #define WILD(node)      ((node)->wild)
 100 #define LOCKNUM(node)   ((node)->locknum)
 101
 102 /*%
 103  * The variable length stuff stored after the node.
 104  */
 105 #define NAME(node)      ((unsigned char *)((node) + 1))
 106 #define OFFSETS(node)   (NAME(node) + NAMELEN(node))
 107
 108 #define NODE_SIZE(node) (sizeof(*node) + \
 109                          NAMELEN(node) + OFFSETLEN(node) + PADBYTES(node))
 110
 111 /*%
 112  * Color management.
 113  */
 114 #define IS_RED(node)            ((node) != NULL && (node)->color == RED)
 115 #define IS_BLACK(node)          ((node) == NULL || (node)->color == BLACK)
 116 #define MAKE_RED(node)          ((node)->color = RED)
 117 #define MAKE_BLACK(node)        ((node)->color = BLACK)
 118
 119 /*%
 120  * Chain management.
 121  *
 122  * The "ancestors" member of chains were removed, with their job now
 123  * being wholly handled by parent pointers (which didn't exist, because
 124  * of memory concerns, when chains were first implemented).
 125  */
 126 #define ADD_LEVEL(chain, node) \
 127                         (chain)->levels[(chain)->level_count++] = (node)
 128
 129 /*%
 130  * The following macros directly access normally private name variables.
 131  * These macros are used to avoid a lot of function calls in the critical
 132  * path of the tree traversal code.
 133  */
 134
 135 #define NODENAME(node, name) \
 136 do { \
 137         (name)->length = NAMELEN(node); \
 138         (name)->labels = OFFSETLEN(node); \
 139         (name)->ndata = NAME(node); \
 140         (name)->offsets = OFFSETS(node); \
 141         (name)->attributes = ATTRS(node); \
 142         (name)->attributes |= DNS_NAMEATTR_READONLY; \
 143 } while (0)
 144
 145 #ifdef DNS_RBT_USEHASH
 146 static isc_result_t
 147 inithash(dns_rbt_t *rbt);
 148 #endif
 149
 150 #ifdef DEBUG
 151 #define inline
 152 /*
 153  * A little something to help out in GDB.
 154  */
 155 dns_name_t Name(dns_rbtnode_t *node);
 156 dns_name_t
 157 Name(dns_rbtnode_t *node) {
 158         dns_name_t name;
 159
 160         dns_name_init(&name, NULL);
 161         if (node != NULL)
 162                 NODENAME(node, &name);
 163
 164         return (name);
 165 }
 166
 167 static void dns_rbt_printnodename(dns_rbtnode_t *node);
 168 #endif
 169
 170 static inline dns_rbtnode_t *
 171 find_up(dns_rbtnode_t *node) {
 172         dns_rbtnode_t *root;
 173
 174         /*
 175          * Return the node in the level above the argument node that points
 176          * to the level the argument node is in.  If the argument node is in
 177          * the top level, the return value is NULL.
 178          */
 179         for (root = node; ! IS_ROOT(root); root = PARENT(root))
 180                 ; /* Nothing. */
 181
 182         return (PARENT(root));
 183 }
 184
 185 /*
 186  * Forward declarations.
 187  */
 188 static isc_result_t
 189 create_node(isc_mem_t *mctx, dns_name_t *name, dns_rbtnode_t **nodep);
 190
 191 #ifdef DNS_RBT_USEHASH
 192 static inline void
 193 hash_node(dns_rbt_t *rbt, dns_rbtnode_t *node, dns_name_t *name);
 194 static inline void
 195 unhash_node(dns_rbt_t *rbt, dns_rbtnode_t *node);
 196 #else
 197 #define hash_node(rbt, node, name) (ISC_R_SUCCESS)
 198 #define unhash_node(rbt, node)
 199 #endif
 200
 201 static inline void
 202 rotate_left(dns_rbtnode_t *node, dns_rbtnode_t **rootp);
 203 static inline void
 204 rotate_right(dns_rbtnode_t *node, dns_rbtnode_t **rootp);
 205
 206 static void
 207 dns_rbt_addonlevel(dns_rbtnode_t *node, dns_rbtnode_t *current, int order,
 208                    dns_rbtnode_t **rootp);
 209
 210 static void
 211 dns_rbt_deletefromlevel(dns_rbtnode_t *delete, dns_rbtnode_t **rootp);
 212
 213 static isc_result_t
 214 dns_rbt_deletetree(dns_rbt_t *rbt, dns_rbtnode_t *node);
 215
 216 static void
 217 dns_rbt_deletetreeflat(dns_rbt_t *rbt, unsigned int quantum,
 218                        dns_rbtnode_t **nodep);
 219
 220 /*
 221  * Initialize a red/black tree of trees.
 222  */
 223 isc_result_t
 224 dns_rbt_create(isc_mem_t *mctx, void (*deleter)(void *, void *),
 225                void *deleter_arg, dns_rbt_t **rbtp)
 226 {
 227 #ifdef DNS_RBT_USEHASH
 228         isc_result_t result;
 229 #endif
 230         dns_rbt_t *rbt;
 231
 232
 233         REQUIRE(mctx != NULL);
 234         REQUIRE(rbtp != NULL && *rbtp == NULL);
 235         REQUIRE(deleter == NULL ? deleter_arg == NULL : 1);
 236
 237         rbt = (dns_rbt_t *)isc_mem_get(mctx, sizeof(*rbt));
 238         if (rbt == NULL)
 239                 return (ISC_R_NOMEMORY);
 240
 241         rbt->mctx = mctx;
 242         rbt->data_deleter = deleter;
 243         rbt->deleter_arg = deleter_arg;
 244         rbt->root = NULL;
 245         rbt->nodecount = 0;
 246         rbt->hashtable = NULL;
 247         rbt->hashsize = 0;
 248
 249 #ifdef DNS_RBT_USEHASH
 250         result = inithash(rbt);
 251         if (result != ISC_R_SUCCESS) {
 252                 isc_mem_put(mctx, rbt, sizeof(*rbt));
 253                 return (result);
 254         }
 255 #endif
 256
 257         rbt->magic = RBT_MAGIC;
 258
 259         *rbtp = rbt;
 260
 261         return (ISC_R_SUCCESS);
 262 }
 263
 264 /*
 265  * Deallocate a red/black tree of trees.
 266  */
 267 void
 268 dns_rbt_destroy(dns_rbt_t **rbtp) {
 269         RUNTIME_CHECK(dns_rbt_destroy2(rbtp, 0) == ISC_R_SUCCESS);
 270 }
 271
 272 isc_result_t
 273 dns_rbt_destroy2(dns_rbt_t **rbtp, unsigned int quantum) {
 274         dns_rbt_t *rbt;
 275
 276         REQUIRE(rbtp != NULL && VALID_RBT(*rbtp));
 277
 278         rbt = *rbtp;
 279
 280         dns_rbt_deletetreeflat(rbt, quantum, &rbt->root);
 281         if (rbt->root != NULL)
 282                 return (ISC_R_QUOTA);
 283
 284         INSIST(rbt->nodecount == 0);
 285
 286         if (rbt->hashtable != NULL)
 287                 isc_mem_put(rbt->mctx, rbt->hashtable,
 288                             rbt->hashsize * sizeof(dns_rbtnode_t *));
 289
 290         rbt->magic = 0;
 291
 292         isc_mem_put(rbt->mctx, rbt, sizeof(*rbt));
 293         *rbtp = NULL;
 294         return (ISC_R_SUCCESS);
 295 }
 296
 297 unsigned int
 298 dns_rbt_nodecount(dns_rbt_t *rbt) {
 299         REQUIRE(VALID_RBT(rbt));
 300         return (rbt->nodecount);
 301 }
 302
 303 static inline isc_result_t
 304 chain_name(dns_rbtnodechain_t *chain, dns_name_t *name,
 305            isc_boolean_t include_chain_end)
 306 {
 307         dns_name_t nodename;
 308         isc_result_t result = ISC_R_SUCCESS;
 309         int i;
 310
 311         dns_name_init(&nodename, NULL);
 312
 313         if (include_chain_end && chain->end != NULL) {
 314                 NODENAME(chain->end, &nodename);
 315                 result = dns_name_copy(&nodename, name, NULL);
 316                 if (result != ISC_R_SUCCESS)
 317                         return (result);
 318         } else
 319                 dns_name_reset(name);
 320
 321         for (i = (int)chain->level_count - 1; i >= 0; i--) {
 322                 NODENAME(chain->levels[i], &nodename);
 323                 result = dns_name_concatenate(name, &nodename, name, NULL);
 324
 325                 if (result != ISC_R_SUCCESS)
 326                         return (result);
 327         }
 328         return (result);
 329 }
 330
 331 static inline isc_result_t
 332 move_chain_to_last(dns_rbtnodechain_t *chain, dns_rbtnode_t *node) {
 333         do {
 334                 /*
 335                  * Go as far right and then down as much as possible,
 336                  * as long as the rightmost node has a down pointer.
 337                  */
 338                 while (RIGHT(node) != NULL)
 339                         node = RIGHT(node);
 340
 341                 if (DOWN(node) == NULL)
 342                         break;
 343
 344                 ADD_LEVEL(chain, node);
 345                 node = DOWN(node);
 346         } while (1);
 347
 348         chain->end = node;
 349
 350         return (ISC_R_SUCCESS);
 351 }
 352
 353 /*
 354  * Add 'name' to tree, initializing its data pointer with 'data'.
 355  */
 356
 357 isc_result_t
 358 dns_rbt_addnode(dns_rbt_t *rbt, dns_name_t *name, dns_rbtnode_t **nodep) {
 359         /*
 360          * Does this thing have too many variables or what?
 361          */
 362         dns_rbtnode_t **root, *parent, *child, *current, *new_current;
 363         dns_name_t *add_name, *new_name, current_name, *prefix, *suffix;
 364         dns_fixedname_t fixedcopy, fixedprefix, fixedsuffix, fnewname;
 365         dns_offsets_t current_offsets;
 366         dns_namereln_t compared;
 367         isc_result_t result = ISC_R_SUCCESS;
 368         dns_rbtnodechain_t chain;
 369         unsigned int common_labels;
 370         unsigned int nlabels, hlabels;
 371         int order;
 372
 373         REQUIRE(VALID_RBT(rbt));
 374         REQUIRE(dns_name_isabsolute(name));
 375         REQUIRE(nodep != NULL && *nodep == NULL);
 376
 377         /*
 378          * Create a copy of the name so the original name structure is
 379          * not modified.
 380          */
 381         dns_fixedname_init(&fixedcopy);
 382         add_name = dns_fixedname_name(&fixedcopy);
 383         dns_name_clone(name, add_name);
 384
 385         if (rbt->root == NULL) {
 386                 result = create_node(rbt->mctx, add_name, &new_current);
 387                 if (result == ISC_R_SUCCESS) {
 388                         rbt->nodecount++;
 389                         new_current->is_root = 1;
 390                         rbt->root = new_current;
 391                         *nodep = new_current;
 392                         hash_node(rbt, new_current, name);
 393                 }
 394                 return (result);
 395         }
 396
 397         dns_rbtnodechain_init(&chain, rbt->mctx);
 398
 399         dns_fixedname_init(&fixedprefix);
 400         dns_fixedname_init(&fixedsuffix);
 401         prefix = dns_fixedname_name(&fixedprefix);
 402         suffix = dns_fixedname_name(&fixedsuffix);
 403
 404         root = &rbt->root;
 405         INSIST(IS_ROOT(*root));
 406         parent = NULL;
 407         current = NULL;
 408         child = *root;
 409         dns_name_init(&current_name, current_offsets);
 410         dns_fixedname_init(&fnewname);
 411         new_name = dns_fixedname_name(&fnewname);
 412         nlabels = dns_name_countlabels(name);
 413         hlabels = 0;
 414
 415         do {
 416                 current = child;
 417
 418                 NODENAME(current, &current_name);
 419                 compared = dns_name_fullcompare(add_name, &current_name,
 420                                                 &order, &common_labels);
 421
 422                 if (compared == dns_namereln_equal) {
 423                         *nodep = current;
 424                         result = ISC_R_EXISTS;
 425                         break;
 426
 427                 }
 428
 429                 if (compared == dns_namereln_none) {
 430
 431                         if (order < 0) {
 432                                 parent = current;
 433                                 child = LEFT(current);
 434
 435                         } else if (order > 0) {
 436                                 parent = current;
 437                                 child = RIGHT(current);
 438
 439                         }
 440
 441                 } else {
 442                         /*
 443                          * This name has some suffix in common with the
 444                          * name at the current node.  If the name at
 445                          * the current node is shorter, that means the
 446                          * new name should be in a subtree.  If the
 447                          * name at the current node is longer, that means
 448                          * the down pointer to this tree should point
 449                          * to a new tree that has the common suffix, and
 450                          * the non-common parts of these two names should
 451                          * start a new tree.
 452                          */
 453                         hlabels += common_labels;
 454                         if (compared == dns_namereln_subdomain) {
 455                                 /*
 456                                  * All of the existing labels are in common,
 457                                  * so the new name is in a subtree.
 458                                  * Whack off the common labels for the
 459                                  * not-in-common part to be searched for
 460                                  * in the next level.
 461                                  */
 462                                 dns_name_split(add_name, common_labels,
 463                                                add_name, NULL);
 464
 465                                 /*
 466                                  * Follow the down pointer (possibly NULL).
 467                                  */
 468                                 root = &DOWN(current);
 469
 470                                 INSIST(*root == NULL ||
 471                                        (IS_ROOT(*root) &&
 472                                         PARENT(*root) == current));
 473
 474                                 parent = NULL;
 475                                 child = DOWN(current);
 476                                 ADD_LEVEL(&chain, current);
 477
 478                         } else {
 479                                 /*
 480                                  * The number of labels in common is fewer
 481                                  * than the number of labels at the current
 482                                  * node, so the current node must be adjusted
 483                                  * to have just the common suffix, and a down
 484                                  * pointer made to a new tree.
 485                                  */
 486
 487                                 INSIST(compared == dns_namereln_commonancestor
 488                                        || compared == dns_namereln_contains);
 489
 490                                 /*
 491                                  * Ensure the number of levels in the tree
 492                                  * does not exceed the number of logical
 493                                  * levels allowed by DNSSEC.
 494                                  *
 495                                  * XXXDCL need a better error result?
 496                                  *
 497                                  * XXXDCL Since chain ancestors were removed,
 498                                  * no longer used by dns_rbt_addonlevel(),
 499                                  * this is the only real use of chains in the
 500                                  * function.  It could be done instead with
 501                                  * a simple integer variable, but I am pressed
 502                                  * for time.
 503                                  */
 504                                 if (chain.level_count ==
 505                                     (sizeof(chain.levels) /
 506                                      sizeof(*chain.levels))) {
 507                                         result = ISC_R_NOSPACE;
 508                                         break;
 509                                 }
 510
 511                                 /*
 512                                  * Split the name into two parts, a prefix
 513                                  * which is the not-in-common parts of the
 514                                  * two names and a suffix that is the common
 515                                  * parts of them.
 516                                  */
 517                                 dns_name_split(&current_name, common_labels,
 518                                                prefix, suffix);
 519                                 result = create_node(rbt->mctx, suffix,
 520                                                      &new_current);
 521
 522                                 if (result != ISC_R_SUCCESS)
 523                                         break;
 524
 525                                 /*
 526                                  * Reproduce the tree attributes of the
 527                                  * current node.
 528                                  */
 529                                 new_current->is_root = current->is_root;
 530                                 PARENT(new_current)  = PARENT(current);
 531                                 LEFT(new_current)    = LEFT(current);
 532                                 RIGHT(new_current)   = RIGHT(current);
 533                                 COLOR(new_current)   = COLOR(current);
 534
 535                                 /*
 536                                  * Fix pointers that were to the current node.
 537                                  */
 538                                 if (parent != NULL) {
 539                                         if (LEFT(parent) == current)
 540                                                 LEFT(parent) = new_current;
 541                                         else
 542                                                 RIGHT(parent) = new_current;
 543                                 }
 544                                 if (LEFT(new_current) != NULL)
 545                                         PARENT(LEFT(new_current)) =
 546                                                 new_current;
 547                                 if (RIGHT(new_current) != NULL)
 548                                         PARENT(RIGHT(new_current)) =
 549                                                 new_current;
 550                                 if (*root == current)
 551                                         *root = new_current;
 552
 553                                 NAMELEN(current) = prefix->length;
 554                                 OFFSETLEN(current) = prefix->labels;
 555                                 memcpy(OFFSETS(current), prefix->offsets,
 556                                        prefix->labels);
 557                                 PADBYTES(current) +=
 558                                        (current_name.length - prefix->length) +
 559                                        (current_name.labels - prefix->labels);
 560
 561                                 /*
 562                                  * Set up the new root of the next level.
 563                                  * By definition it will not be the top
 564                                  * level tree, so clear DNS_NAMEATTR_ABSOLUTE.
 565                                  */
 566                                 current->is_root = 1;
 567                                 PARENT(current) = new_current;
 568                                 DOWN(new_current) = current;
 569                                 root = &DOWN(new_current);
 570
 571                                 ADD_LEVEL(&chain, new_current);
 572
 573                                 LEFT(current) = NULL;
 574                                 RIGHT(current) = NULL;
 575
 576                                 MAKE_BLACK(current);
 577                                 ATTRS(current) &= ~DNS_NAMEATTR_ABSOLUTE;
 578
 579                                 rbt->nodecount++;
 580                                 dns_name_getlabelsequence(name,
 581                                                           nlabels - hlabels,
 582                                                           hlabels, new_name);
 583                                 hash_node(rbt, new_current, new_name);
 584
 585                                 if (common_labels ==
 586                                     dns_name_countlabels(add_name)) {
 587                                         /*
 588                                          * The name has been added by pushing
 589                                          * the not-in-common parts down to
 590                                          * a new level.
 591                                          */
 592                                         *nodep = new_current;
 593                                         return (ISC_R_SUCCESS);
 594
 595                                 } else {
 596                                         /*
 597                                          * The current node has no data,
 598                                          * because it is just a placeholder.
 599                                          * Its data pointer is already NULL
 600                                          * from create_node()), so there's
 601                                          * nothing more to do to it.
 602                                          */
 603
 604                                         /*
 605                                          * The not-in-common parts of the new
 606                                          * name will be inserted into the new
 607                                          * level following this loop (unless
 608                                          * result != ISC_R_SUCCESS, which
 609                                          * is tested after the loop ends).
 610                                          */
 611                                         dns_name_split(add_name, common_labels,
 612                                                        add_name, NULL);
 613
 614                                         break;
 615                                 }
 616
 617                         }
 618
 619                 }
 620
 621         } while (child != NULL);
 622
 623         if (result == ISC_R_SUCCESS)
 624                 result = create_node(rbt->mctx, add_name, &new_current);
 625
 626         if (result == ISC_R_SUCCESS) {
 627                 dns_rbt_addonlevel(new_current, current, order, root);
 628                 rbt->nodecount++;
 629                 *nodep = new_current;
 630                 hash_node(rbt, new_current, name);
 631         }
 632
 633         return (result);
 634 }
 635
 636 /*
 637  * Add a name to the tree of trees, associating it with some data.
 638  */
 639 isc_result_t
 640 dns_rbt_addname(dns_rbt_t *rbt, dns_name_t *name, void *data) {
 641         isc_result_t result;
 642         dns_rbtnode_t *node;
 643
 644         REQUIRE(VALID_RBT(rbt));
 645         REQUIRE(dns_name_isabsolute(name));
 646
 647         node = NULL;
 648
 649         result = dns_rbt_addnode(rbt, name, &node);
 650
 651         /*
 652          * dns_rbt_addnode will report the node exists even when
 653          * it does not have data associated with it, but the
 654          * dns_rbt_*name functions all behave depending on whether
 655          * there is data associated with a node.
 656          */
 657         if (result == ISC_R_SUCCESS ||
 658             (result == ISC_R_EXISTS && DATA(node) == NULL)) {
 659                 DATA(node) = data;
 660                 result = ISC_R_SUCCESS;
 661         }
 662
 663         return (result);
 664 }
 665
 666 /*
 667  * Find the node for "name" in the tree of trees.
 668  */
 669 isc_result_t
 670 dns_rbt_findnode(dns_rbt_t *rbt, dns_name_t *name, dns_name_t *foundname,
 671                  dns_rbtnode_t **node, dns_rbtnodechain_t *chain,
 672                  unsigned int options, dns_rbtfindcallback_t callback,
 673                  void *callback_arg)
 674 {
 675         dns_rbtnode_t *current, *last_compared, *current_root;
 676         dns_rbtnodechain_t localchain;
 677         dns_name_t *search_name, current_name, *callback_name;
 678         dns_fixedname_t fixedcallbackname, fixedsearchname;
 679         dns_namereln_t compared;
 680         isc_result_t result, saved_result;
 681         unsigned int common_labels;
 682         unsigned int hlabels = 0;
 683         int order;
 684
 685         REQUIRE(VALID_RBT(rbt));
 686         REQUIRE(dns_name_isabsolute(name));
 687         REQUIRE(node != NULL && *node == NULL);
 688         REQUIRE((options & (DNS_RBTFIND_NOEXACT | DNS_RBTFIND_NOPREDECESSOR))
 689                 !=         (DNS_RBTFIND_NOEXACT | DNS_RBTFIND_NOPREDECESSOR));
 690
 691         /*
 692          * If there is a chain it needs to appear to be in a sane state,
 693          * otherwise a chain is still needed to generate foundname and
 694          * callback_name.
 695          */
 696         if (chain == NULL) {
 697                 options |= DNS_RBTFIND_NOPREDECESSOR;
 698                 chain = &localchain;
 699                 dns_rbtnodechain_init(chain, rbt->mctx);
 700         } else
 701                 dns_rbtnodechain_reset(chain);
 702
 703         if (rbt->root == NULL)
 704                 return (ISC_R_NOTFOUND);
 705         else {
 706                 /*
 707                  * Appease GCC about variables it incorrectly thinks are
 708                  * possibly used uninitialized.
 709                  */
 710                 compared = dns_namereln_none;
 711                 last_compared = NULL;
 712         }
 713
 714         dns_fixedname_init(&fixedcallbackname);
 715         callback_name = dns_fixedname_name(&fixedcallbackname);
 716
 717         /*
 718          * search_name is the name segment being sought in each tree level.
 719          * By using a fixedname, the search_name will definitely have offsets
 720          * for use by any splitting.
 721          * By using dns_name_clone, no name data should be copied thanks to
 722          * the lack of bitstring labels.
 723          */
 724         dns_fixedname_init(&fixedsearchname);
 725         search_name = dns_fixedname_name(&fixedsearchname);
 726         dns_name_clone(name, search_name);
 727
 728         dns_name_init(&current_name, NULL);
 729
 730         saved_result = ISC_R_SUCCESS;
 731         current = rbt->root;
 732         current_root = rbt->root;
 733
 734         while (current != NULL) {
 735                 NODENAME(current, &current_name);
 736                 compared = dns_name_fullcompare(search_name, &current_name,
 737                                                 &order, &common_labels);
 738                 last_compared = current;
 739
 740                 if (compared == dns_namereln_equal)
 741                         break;
 742
 743                 if (compared == dns_namereln_none) {
 744 #ifdef DNS_RBT_USEHASH
 745                         dns_name_t hash_name;
 746                         dns_rbtnode_t *hnode;
 747                         dns_rbtnode_t *up_current;
 748                         unsigned int nlabels;
 749                         unsigned int tlabels = 1;
 750                         unsigned int hash;
 751
 752                         /*
 753                          * If there is no hash table, hashing can't be done.
 754                          */
 755                         if (rbt->hashtable == NULL)
 756                                 goto nohash;
 757
 758                         /*
 759                          * The case of current != current_root, that
 760                          * means a left or right pointer was followed,
 761                          * only happens when the algorithm fell through to
 762                          * the traditional binary search because of a
 763                          * bitstring label.  Since we dropped the bitstring
 764                          * support, this should not happen.
 765                          */
 766                         INSIST(current == current_root);
 767
 768                         nlabels = dns_name_countlabels(search_name);
 769
 770                         /*
 771                          * current_root is the root of the current level, so
 772                          * it's parent is the same as it's "up" pointer.
 773                          */
 774                         up_current = PARENT(current_root);
 775                         dns_name_init(&hash_name, NULL);
 776
 777                 hashagain:
 778                         /*
 779                          * Hash includes tail.
 780                          */
 781                         dns_name_getlabelsequence(name,
 782                                                   nlabels - tlabels,
 783                                                   hlabels + tlabels,
 784                                                   &hash_name);
 785                         hash = dns_name_fullhash(&hash_name, ISC_FALSE);
 786                         dns_name_getlabelsequence(search_name,
 787                                                   nlabels - tlabels,
 788                                                   tlabels, &hash_name);
 789
 790                         for (hnode = rbt->hashtable[hash % rbt->hashsize];
 791                              hnode != NULL;
 792                              hnode = hnode->hashnext)
 793                         {
 794                                 dns_name_t hnode_name;
 795
 796                                 if (hash != HASHVAL(hnode))
 797                                         continue;
 798                                 if (find_up(hnode) != up_current)
 799                                         continue;
 800                                 dns_name_init(&hnode_name, NULL);
 801                                 NODENAME(hnode, &hnode_name);
 802                                 if (dns_name_equal(&hnode_name, &hash_name))
 803                                         break;
 804                         }
 805
 806                         if (hnode != NULL) {
 807                                 current = hnode;
 808                                 /*
 809                                  * This is an optimization.  If hashing found
 810                                  * the right node, the next call to
 811                                  * dns_name_fullcompare() would obviously
 812                                  * return _equal or _subdomain.  Determine
 813                                  * which of those would be the case by
 814                                  * checking if the full name was hashed.  Then
 815                                  * make it look like dns_name_fullcompare
 816                                  * was called and jump to the right place.
 817                                  */
 818                                 if (tlabels == nlabels) {
 819                                         compared = dns_namereln_equal;
 820                                         break;
 821                                 } else {
 822                                         common_labels = tlabels;
 823                                         compared = dns_namereln_subdomain;
 824                                         goto subdomain;
 825                                 }
 826                         }
 827
 828                         if (tlabels++ < nlabels)
 829                                 goto hashagain;
 830
 831                         /*
 832                          * All of the labels have been tried against the hash
 833                          * table.  Since we dropped the support of bitstring
 834                          * labels, the name isn't in the table.
 835                          */
 836                         current = NULL;
 837                         continue;
 838
 839                 nohash:
 840 #endif /* DNS_RBT_USEHASH */
 841                         /*
 842                          * Standard binary search tree movement.
 843                          */
 844                         if (order < 0)
 845                                 current = LEFT(current);
 846                         else
 847                                 current = RIGHT(current);
 848
 849                 } else {
 850                         /*
 851                          * The names have some common suffix labels.
 852                          *
 853                          * If the number in common are equal in length to
 854                          * the current node's name length, then follow the
 855                          * down pointer and search in the new tree.
 856                          */
 857                         if (compared == dns_namereln_subdomain) {
 858                 subdomain:
 859                                 /*
 860                                  * Whack off the current node's common parts
 861                                  * for the name to search in the next level.
 862                                  */
 863                                 dns_name_split(search_name, common_labels,
 864                                                search_name, NULL);
 865                                 hlabels += common_labels;
 866                                 /*
 867                                  * This might be the closest enclosing name.
 868                                  */
 869                                 if (DATA(current) != NULL ||
 870                                     (options & DNS_RBTFIND_EMPTYDATA) != 0)
 871                                         *node = current;
 872
 873                                 /*
 874                                  * Point the chain to the next level.   This
 875                                  * needs to be done before 'current' is pointed
 876                                  * there because the callback in the next
 877                                  * block of code needs the current 'current',
 878                                  * but in the event the callback requests that
 879                                  * the search be stopped then the
 880                                  * DNS_R_PARTIALMATCH code at the end of this
 881                                  * function needs the chain pointed to the
 882                                  * next level.
 883                                  */
 884                                 ADD_LEVEL(chain, current);
 885
 886                                 /*
 887                                  * The caller may want to interrupt the
 888                                  * downward search when certain special nodes
 889                                  * are traversed.  If this is a special node,
 890                                  * the callback is used to learn what the
 891                                  * caller wants to do.
 892                                  */
 893                                 if (callback != NULL &&
 894                                     FINDCALLBACK(current)) {
 895                                         result = chain_name(chain,
 896                                                             callback_name,
 897                                                             ISC_FALSE);
 898                                         if (result != ISC_R_SUCCESS) {
 899                                                 dns_rbtnodechain_reset(chain);
 900                                                 return (result);
 901                                         }
 902
 903                                         result = (callback)(current,
 904                                                             callback_name,
 905                                                             callback_arg);
 906                                         if (result != DNS_R_CONTINUE) {
 907                                                 saved_result = result;
 908                                                 /*
 909                                                  * Treat this node as if it
 910                                                  * had no down pointer.
 911                                                  */
 912                                                 current = NULL;
 913                                                 break;
 914                                         }
 915                                 }
 916
 917                                 /*
 918                                  * Finally, head to the next tree level.
 919                                  */
 920                                 current = DOWN(current);
 921                                 current_root = current;
 922
 923                         } else {
 924                                 /*
 925                                  * Though there are labels in common, the
 926                                  * entire name at this node is not common
 927                                  * with the search name so the search
 928                                  * name does not exist in the tree.
 929                                  */
 930                                 INSIST(compared == dns_namereln_commonancestor
 931                                        || compared == dns_namereln_contains);
 932
 933                                 current = NULL;
 934                         }
 935                 }
 936         }
 937
 938         /*
 939          * If current is not NULL, NOEXACT is not disallowing exact matches,
 940          * and either the node has data or an empty node is ok, return
 941          * ISC_R_SUCCESS to indicate an exact match.
 942          */
 943         if (current != NULL && (options & DNS_RBTFIND_NOEXACT) == 0 &&
 944             (DATA(current) != NULL ||
 945              (options & DNS_RBTFIND_EMPTYDATA) != 0)) {
 946                 /*
 947                  * Found an exact match.
 948                  */
 949                 chain->end = current;
 950                 chain->level_matches = chain->level_count;
 951
 952                 if (foundname != NULL)
 953                         result = chain_name(chain, foundname, ISC_TRUE);
 954                 else
 955                         result = ISC_R_SUCCESS;
 956
 957                 if (result == ISC_R_SUCCESS) {
 958                         *node = current;
 959                         result = saved_result;
 960                 } else
 961                         *node = NULL;
 962         } else {
 963                 /*
 964                  * Did not find an exact match (or did not want one).
 965                  */
 966                 if (*node != NULL) {
 967                         /*
 968                          * ... but found a partially matching superdomain.
 969                          * Unwind the chain to the partial match node
 970                          * to set level_matches to the level above the node,
 971                          * and then to derive the name.
 972                          *
 973                          * chain->level_count is guaranteed to be at least 1
 974                          * here because by definition of finding a superdomain,
 975                          * the chain is pointed to at least the first subtree.
 976                          */
 977                         chain->level_matches = chain->level_count - 1;
 978
 979                         while (chain->levels[chain->level_matches] != *node) {
 980                                 INSIST(chain->level_matches > 0);
 981                                 chain->level_matches--;
 982                         }
 983
 984                         if (foundname != NULL) {
 985                                 unsigned int saved_count = chain->level_count;
 986
 987                                 chain->level_count = chain->level_matches + 1;
 988
 989                                 result = chain_name(chain, foundname,
 990                                                     ISC_FALSE);
 991
 992                                 chain->level_count = saved_count;
 993                         } else
 994                                 result = ISC_R_SUCCESS;
 995
 996                         if (result == ISC_R_SUCCESS)
 997                                 result = DNS_R_PARTIALMATCH;
 998
 999                 } else
1000                         result = ISC_R_NOTFOUND;
1001
1002                 if (current != NULL) {
1003                         /*
1004                          * There was an exact match but either
1005                          * DNS_RBTFIND_NOEXACT was set, or
1006                          * DNS_RBTFIND_EMPTYDATA was set and the node had no
1007                          * data.  A policy decision was made to set the
1008                          * chain to the exact match, but this is subject
1009                          * to change if it becomes apparent that something
1010                          * else would be more useful.  It is important that
1011                          * this case is handled here, because the predecessor
1012                          * setting code below assumes the match was not exact.
1013                          */
1014                         INSIST(((options & DNS_RBTFIND_NOEXACT) != 0) ||
1015                                ((options & DNS_RBTFIND_EMPTYDATA) == 0 &&
1016                                 DATA(current) == NULL));
1017                         chain->end = current;
1018
1019                 } else if ((options & DNS_RBTFIND_NOPREDECESSOR) != 0) {
1020                         /*
1021                          * Ensure the chain points nowhere.
1022                          */
1023                         chain->end = NULL;
1024
1025                 } else {
1026                         /*
1027                          * Since there was no exact match, the chain argument
1028                          * needs to be pointed at the DNSSEC predecessor of
1029                          * the search name.
1030                          */
1031                         if (compared == dns_namereln_subdomain) {
1032                                 /*
1033                                  * Attempted to follow a down pointer that was
1034                                  * NULL, which means the searched for name was
1035                                  * a subdomain of a terminal name in the tree.
1036                                  * Since there are no existing subdomains to
1037                                  * order against, the terminal name is the
1038                                  * predecessor.
1039                                  */
1040                                 INSIST(chain->level_count > 0);
1041                                 INSIST(chain->level_matches <
1042                                        chain->level_count);
1043                                 chain->end =
1044                                         chain->levels[--chain->level_count];
1045
1046                         } else {
1047                                 isc_result_t result2;
1048
1049                                 /*
1050                                  * Point current to the node that stopped
1051                                  * the search.
1052                                  *
1053                                  * With the hashing modification that has been
1054                                  * added to the algorithm, the stop node of a
1055                                  * standard binary search is not known.  So it
1056                                  * has to be found.  There is probably a more
1057                                  * clever way of doing this.
1058                                  *
1059                                  * The assignment of current to NULL when
1060                                  * the relationship is *not* dns_namereln_none,
1061                                  * even though it later gets set to the same
1062                                  * last_compared anyway, is simply to not push
1063                                  * the while loop in one more level of
1064                                  * indentation.
1065                                  */
1066                                 if (compared == dns_namereln_none)
1067                                         current = last_compared;
1068                                 else
1069                                         current = NULL;
1070
1071                                 while (current != NULL) {
1072                                         NODENAME(current, &current_name);
1073                                         compared = dns_name_fullcompare(
1074                                                                 search_name,
1075                                                                 &current_name,
1076                                                                 &order,
1077                                                                 &common_labels);
1078
1079                                         last_compared = current;
1080
1081                                         /*
1082                                          * Standard binary search movement.
1083                                          */
1084                                         if (order < 0)
1085                                                 current = LEFT(current);
1086                                         else
1087                                                 current = RIGHT(current);
1088
1089                                 }
1090
1091                                 current = last_compared;
1092
1093                                 /*
1094                                  * Reached a point within a level tree that
1095                                  * positively indicates the name is not
1096                                  * present, but the stop node could be either
1097                                  * less than the desired name (order > 0) or
1098                                  * greater than the desired name (order < 0).
1099                                  *
1100                                  * If the stop node is less, it is not
1101                                  * necessarily the predecessor.  If the stop
1102                                  * node has a down pointer, then the real
1103                                  * predecessor is at the end of a level below
1104                                  * (not necessarily the next level).
1105                                  * Move down levels until the rightmost node
1106                                  * does not have a down pointer.
1107                                  *
1108                                  * When the stop node is greater, it is
1109                                  * the successor.  All the logic for finding
1110                                  * the predecessor is handily encapsulated
1111                                  * in dns_rbtnodechain_prev.  In the event
1112                                  * that the search name is less than anything
1113                                  * else in the tree, the chain is reset.
1114                                  * XXX DCL What is the best way for the caller
1115                                  *         to know that the search name has
1116                                  *         no predecessor?
1117                                  */
1118
1119
1120                                 if (order > 0) {
1121                                         if (DOWN(current) != NULL) {
1122                                                 ADD_LEVEL(chain, current);
1123
1124                                                 result2 =
1125                                                       move_chain_to_last(chain,
1126                                                                 DOWN(current));
1127
1128                                                 if (result2 != ISC_R_SUCCESS)
1129                                                         result = result2;
1130                                         } else
1131                                                 /*
1132                                                  * Ah, the pure and simple
1133                                                  * case.  The stop node is the
1134                                                  * predecessor.
1135                                                  */
1136                                                 chain->end = current;
1137
1138                                 } else {
1139                                         INSIST(order < 0);
1140
1141                                         chain->end = current;
1142
1143                                         result2 = dns_rbtnodechain_prev(chain,
1144                                                                         NULL,
1145                                                                         NULL);
1146                                         if (result2 == ISC_R_SUCCESS ||
1147                                             result2 == DNS_R_NEWORIGIN)
1148                                                 ;       /* Nothing. */
1149                                         else if (result2 == ISC_R_NOMORE)
1150                                                 /*
1151                                                  * There is no predecessor.
1152                                                  */
1153                                                 dns_rbtnodechain_reset(chain);
1154                                         else
1155                                                 result = result2;
1156                                 }
1157
1158                         }
1159                 }
1160         }
1161
1162         ENSURE(*node == NULL || DNS_RBTNODE_VALID(*node));
1163
1164         return (result);
1165 }
1166
1167 /*
1168  * Get the data pointer associated with 'name'.
1169  */
1170 isc_result_t
1171 dns_rbt_findname(dns_rbt_t *rbt, dns_name_t *name, unsigned int options,
1172                  dns_name_t *foundname, void **data) {
1173         dns_rbtnode_t *node = NULL;
1174         isc_result_t result;
1175
1176         REQUIRE(data != NULL && *data == NULL);
1177
1178         result = dns_rbt_findnode(rbt, name, foundname, &node, NULL,
1179                                   options, NULL, NULL);
1180
1181         if (node != NULL &&
1182             (DATA(node) != NULL || (options & DNS_RBTFIND_EMPTYDATA) != 0))
1183                 *data = DATA(node);
1184         else
1185                 result = ISC_R_NOTFOUND;
1186
1187         return (result);
1188 }
1189
1190 /*
1191  * Delete a name from the tree of trees.
1192  */
1193 isc_result_t
1194 dns_rbt_deletename(dns_rbt_t *rbt, dns_name_t *name, isc_boolean_t recurse) {
1195         dns_rbtnode_t *node = NULL;
1196         isc_result_t result;
1197
1198         REQUIRE(VALID_RBT(rbt));
1199         REQUIRE(dns_name_isabsolute(name));
1200
1201         /*
1202          * First, find the node.
1203          *
1204          * When searching, the name might not have an exact match:
1205          * consider a.b.a.com, b.b.a.com and c.b.a.com as the only
1206          * elements of a tree, which would make layer 1 a single
1207          * node tree of "b.a.com" and layer 2 a three node tree of
1208          * a, b, and c.  Deleting a.com would find only a partial depth
1209          * match in the first layer.  Should it be a requirement that
1210          * that the name to be deleted have data?  For now, it is.
1211          *
1212          * ->dirty, ->locknum and ->references are ignored; they are
1213          * solely the province of rbtdb.c.
1214          */
1215         result = dns_rbt_findnode(rbt, name, NULL, &node, NULL,
1216                                   DNS_RBTFIND_NOOPTIONS, NULL, NULL);
1217
1218         if (result == ISC_R_SUCCESS) {
1219                 if (DATA(node) != NULL)
1220                         result = dns_rbt_deletenode(rbt, node, recurse);
1221                 else
1222                         result = ISC_R_NOTFOUND;
1223
1224         } else if (result == DNS_R_PARTIALMATCH)
1225                 result = ISC_R_NOTFOUND;
1226
1227         return (result);
1228 }
1229
1230 /*
1231  * Remove a node from the tree of trees.
1232  *
1233  * NOTE WELL: deletion is *not* symmetric with addition; that is, reversing
1234  * a sequence of additions to be deletions will not generally get the
1235  * tree back to the state it started in.  For example, if the addition
1236  * of "b.c" caused the node "a.b.c" to be split, pushing "a" to its own level,
1237  * then the subsequent deletion of "b.c" will not cause "a" to be pulled up,
1238  * restoring "a.b.c".  The RBT *used* to do this kind of rejoining, but it
1239  * turned out to be a bad idea because it could corrupt an active nodechain
1240  * that had "b.c" as one of its levels -- and the RBT has no idea what
1241  * nodechains are in use by callers, so it can't even *try* to helpfully
1242  * fix them up (which would probably be doomed to failure anyway).
1243  *
1244  * Similarly, it is possible to leave the tree in a state where a supposedly
1245  * deleted node still exists.  The first case of this is obvious; take
1246  * the tree which has "b.c" on one level, pointing to "a".  Now deleted "b.c".
1247  * It was just established in the previous paragraph why we can't pull "a"
1248  * back up to its parent level.  But what happens when "a" then gets deleted?
1249  * "b.c" is left hanging around without data or children.  This condition
1250  * is actually pretty easy to detect, but ... should it really be removed?
1251  * Is a chain pointing to it?  An iterator?  Who knows!  (Note that the
1252  * references structure member cannot be looked at because it is private to
1253  * rbtdb.)  This is ugly and makes me unhappy, but after hours of trying to
1254  * make it more aesthetically proper and getting nowhere, this is the way it
1255  * is going to stay until such time as it proves to be a *real* problem.
1256  *
1257  * Finally, for reference, note that the original routine that did node
1258  * joining was called join_nodes().  It has been excised, living now only
1259  * in the CVS history, but comments have been left behind that point to it just
1260  * in case someone wants to muck with this some more.
1261  *
1262  * The one positive aspect of all of this is that joining used to have a
1263  * case where it might fail.  Without trying to join, now this function always
1264  * succeeds. It still returns isc_result_t, though, so the API wouldn't change.
1265  */
1266 isc_result_t
1267 dns_rbt_deletenode(dns_rbt_t *rbt, dns_rbtnode_t *node, isc_boolean_t recurse)
1268 {
1269         dns_rbtnode_t *parent;
1270
1271         REQUIRE(VALID_RBT(rbt));
1272         REQUIRE(DNS_RBTNODE_VALID(node));
1273
1274         if (DOWN(node) != NULL) {
1275                 if (recurse)
1276                         RUNTIME_CHECK(dns_rbt_deletetree(rbt, DOWN(node))
1277                                       == ISC_R_SUCCESS);
1278                 else {
1279                         if (DATA(node) != NULL && rbt->data_deleter != NULL)
1280                                 rbt->data_deleter(DATA(node), rbt->deleter_arg);
1281                         DATA(node) = NULL;
1282
1283                         /*
1284                          * Since there is at least one node below this one and
1285                          * no recursion was requested, the deletion is
1286                          * complete.  The down node from this node might be all
1287                          * by itself on a single level, so join_nodes() could
1288                          * be used to collapse the tree (with all the caveats
1289                          * of the comment at the start of this function).
1290                          */
1291                         return (ISC_R_SUCCESS);
1292                 }
1293         }
1294
1295         /*
1296          * Note the node that points to the level of the node that is being
1297          * deleted.  If the deleted node is the top level, parent will be set
1298          * to NULL.
1299          */
1300         parent = find_up(node);
1301
1302         /*
1303          * This node now has no down pointer (either because it didn't
1304          * have one to start, or because it was recursively removed).
1305          * So now the node needs to be removed from this level.
1306          */
1307         dns_rbt_deletefromlevel(node, parent == NULL ? &rbt->root :
1308                                                        &DOWN(parent));
1309
1310         if (DATA(node) != NULL && rbt->data_deleter != NULL)
1311                 rbt->data_deleter(DATA(node), rbt->deleter_arg);
1312
1313         unhash_node(rbt, node);
1314 #if DNS_RBT_USEMAGIC
1315         node->magic = 0;
1316 #endif
1317         dns_rbtnode_refdestroy(node);
1318         isc_mem_put(rbt->mctx, node, NODE_SIZE(node));
1319         rbt->nodecount--;
1320
1321         /*
1322          * There are now two special cases that can exist that would
1323          * not have existed if the tree had been created using only
1324          * the names that now exist in it.  (This is all related to
1325          * join_nodes() as described in this function's introductory comment.)
1326          * Both cases exist when the deleted node's parent (the node
1327          * that pointed to the deleted node's level) is not null but
1328          * it has no data:  parent != NULL && DATA(parent) == NULL.
1329          *
1330          * The first case is that the deleted node was the last on its level:
1331          * DOWN(parent) == NULL.  This case can only exist if the parent was
1332          * previously deleted -- and so now, apparently, the parent should go
1333          * away.  That can't be done though because there might be external
1334          * references to it, such as through a nodechain.
1335          *
1336          * The other case also involves a parent with no data, but with the
1337          * deleted node being the next-to-last node instead of the last:
1338          * LEFT(DOWN(parent)) == NULL && RIGHT(DOWN(parent)) == NULL.
1339          * Presumably now the remaining node on the level should be joined
1340          * with the parent, but it's already been described why that can't be
1341          * done.
1342          */
1343
1344         /*
1345          * This function never fails.
1346          */
1347         return (ISC_R_SUCCESS);
1348 }
1349
1350 void
1351 dns_rbt_namefromnode(dns_rbtnode_t *node, dns_name_t *name) {
1352
1353         REQUIRE(DNS_RBTNODE_VALID(node));
1354         REQUIRE(name != NULL);
1355         REQUIRE(name->offsets == NULL);
1356
1357         NODENAME(node, name);
1358 }
1359
1360 isc_result_t
1361 dns_rbt_fullnamefromnode(dns_rbtnode_t *node, dns_name_t *name) {
1362         dns_name_t current;
1363         isc_result_t result;
1364
1365         REQUIRE(DNS_RBTNODE_VALID(node));
1366         REQUIRE(name != NULL);
1367         REQUIRE(name->buffer != NULL);
1368
1369         dns_name_init(&current, NULL);
1370         dns_name_reset(name);
1371
1372         do {
1373                 INSIST(node != NULL);
1374
1375                 NODENAME(node, &current);
1376
1377                 result = dns_name_concatenate(name, &current, name, NULL);
1378                 if (result != ISC_R_SUCCESS)
1379                         break;
1380
1381                 node = find_up(node);
1382         } while (! dns_name_isabsolute(name));
1383
1384         return (result);
1385 }
1386
1387 char *
1388 dns_rbt_formatnodename(dns_rbtnode_t *node, char *printname, unsigned int size)
1389 {
1390         dns_fixedname_t fixedname;
1391         dns_name_t *name;
1392         isc_result_t result;
1393
1394         REQUIRE(DNS_RBTNODE_VALID(node));
1395         REQUIRE(printname != NULL);
1396
1397         dns_fixedname_init(&fixedname);
1398         name = dns_fixedname_name(&fixedname);
1399         result = dns_rbt_fullnamefromnode(node, name);
1400         if (result == ISC_R_SUCCESS)
1401                 dns_name_format(name, printname, size);
1402         else
1403                 snprintf(printname, size, "<error building name: %s>",
1404                          dns_result_totext(result));
1405
1406         return (printname);
1407 }
1408
1409 static isc_result_t
1410 create_node(isc_mem_t *mctx, dns_name_t *name, dns_rbtnode_t **nodep) {
1411         dns_rbtnode_t *node;
1412         isc_region_t region;
1413         unsigned int labels;
1414
1415         REQUIRE(name->offsets != NULL);
1416
1417         dns_name_toregion(name, &region);
1418         labels = dns_name_countlabels(name);
1419         ENSURE(labels > 0);
1420
1421         /*
1422          * Allocate space for the node structure, the name, and the offsets.
1423          */
1424         node = (dns_rbtnode_t *)isc_mem_get(mctx, sizeof(*node) +
1425                                             region.length + labels);
1426
1427         if (node == NULL)
1428                 return (ISC_R_NOMEMORY);
1429
1430         node->is_root = 0;
1431         PARENT(node) = NULL;
1432         RIGHT(node) = NULL;
1433         LEFT(node) = NULL;
1434         DOWN(node) = NULL;
1435         DATA(node) = NULL;
1436 #ifdef DNS_RBT_USEHASH
1437         HASHNEXT(node) = NULL;
1438         HASHVAL(node) = 0;
1439 #endif
1440
1441         ISC_LINK_INIT(node, deadlink);
1442
1443         LOCKNUM(node) = 0;
1444         WILD(node) = 0;
1445         DIRTY(node) = 0;
1446         dns_rbtnode_refinit(node, 0);
1447         node->find_callback = 0;
1448
1449         MAKE_BLACK(node);
1450
1451         /*
1452          * The following is stored to make reconstructing a name from the
1453          * stored value in the node easy:  the length of the name, the number
1454          * of labels, whether the name is absolute or not, the name itself,
1455          * and the name's offsets table.
1456          *
1457          * XXX RTH
1458          *      The offsets table could be made smaller by eliminating the
1459          *      first offset, which is always 0.  This requires changes to
1460          *      lib/dns/name.c.
1461          */
1462         NAMELEN(node) = region.length;
1463         PADBYTES(node) = 0;
1464         OFFSETLEN(node) = labels;
1465         ATTRS(node) = name->attributes;
1466
1467         memcpy(NAME(node), region.base, region.length);
1468         memcpy(OFFSETS(node), name->offsets, labels);
1469
1470 #if DNS_RBT_USEMAGIC
1471         node->magic = DNS_RBTNODE_MAGIC;
1472 #endif
1473         *nodep = node;
1474
1475         return (ISC_R_SUCCESS);
1476 }
1477
1478 #ifdef DNS_RBT_USEHASH
1479 static inline void
1480 hash_add_node(dns_rbt_t *rbt, dns_rbtnode_t *node, dns_name_t *name) {
1481         unsigned int hash;
1482
1483         HASHVAL(node) = dns_name_fullhash(name, ISC_FALSE);
1484
1485         hash = HASHVAL(node) % rbt->hashsize;
1486         HASHNEXT(node) = rbt->hashtable[hash];
1487
1488         rbt->hashtable[hash] = node;
1489 }
1490
1491 static isc_result_t
1492 inithash(dns_rbt_t *rbt) {
1493         unsigned int bytes;
1494
1495         rbt->hashsize = RBT_HASH_SIZE;
1496         bytes = rbt->hashsize * sizeof(dns_rbtnode_t *);
1497         rbt->hashtable = isc_mem_get(rbt->mctx, bytes);
1498
1499         if (rbt->hashtable == NULL)
1500                 return (ISC_R_NOMEMORY);
1501
1502         memset(rbt->hashtable, 0, bytes);
1503
1504         return (ISC_R_SUCCESS);
1505 }
1506
1507 static void
1508 rehash(dns_rbt_t *rbt) {
1509         unsigned int oldsize;
1510         dns_rbtnode_t **oldtable;
1511         dns_rbtnode_t *node;
1512         unsigned int hash;
1513         unsigned int i;
1514
1515         oldsize = rbt->hashsize;
1516         oldtable = rbt->hashtable;
1517         rbt->hashsize *= 2 + 1;
1518         rbt->hashtable = isc_mem_get(rbt->mctx,
1519                                      rbt->hashsize * sizeof(dns_rbtnode_t *));
1520         if (rbt->hashtable == NULL) {
1521                 rbt->hashtable = oldtable;
1522                 rbt->hashsize = oldsize;
1523                 return;
1524         }
1525
1526         for (i = 0; i < rbt->hashsize; i++)
1527                 rbt->hashtable[i] = NULL;
1528
1529         for (i = 0; i < oldsize; i++) {
1530                 node = oldtable[i];
1531                 while (node != NULL) {
1532                         hash = HASHVAL(node) % rbt->hashsize;
1533                         oldtable[i] = HASHNEXT(node);
1534                         HASHNEXT(node) = rbt->hashtable[hash];
1535                         rbt->hashtable[hash] = node;
1536                         node = oldtable[i];
1537                 }
1538         }
1539
1540         isc_mem_put(rbt->mctx, oldtable, oldsize * sizeof(dns_rbtnode_t *));
1541 }
1542
1543 static inline void
1544 hash_node(dns_rbt_t *rbt, dns_rbtnode_t *node, dns_name_t *name) {
1545
1546         REQUIRE(DNS_RBTNODE_VALID(node));
1547
1548         if (rbt->nodecount >= (rbt->hashsize *3))
1549                 rehash(rbt);
1550
1551         hash_add_node(rbt, node, name);
1552 }
1553
1554 static inline void
1555 unhash_node(dns_rbt_t *rbt, dns_rbtnode_t *node) {
1556         unsigned int bucket;
1557         dns_rbtnode_t *bucket_node;
1558
1559         REQUIRE(DNS_RBTNODE_VALID(node));
1560
1561         if (rbt->hashtable != NULL) {
1562                 bucket = HASHVAL(node) % rbt->hashsize;
1563                 bucket_node = rbt->hashtable[bucket];
1564
1565                 if (bucket_node == node)
1566                         rbt->hashtable[bucket] = HASHNEXT(node);
1567                 else {
1568                         while (HASHNEXT(bucket_node) != node) {
1569                                 INSIST(HASHNEXT(bucket_node) != NULL);
1570                                 bucket_node = HASHNEXT(bucket_node);
1571                         }
1572                         HASHNEXT(bucket_node) = HASHNEXT(node);
1573                 }
1574         }
1575 }
1576 #endif /* DNS_RBT_USEHASH */
1577
1578 static inline void
1579 rotate_left(dns_rbtnode_t *node, dns_rbtnode_t **rootp) {
1580         dns_rbtnode_t *child;
1581
1582         REQUIRE(DNS_RBTNODE_VALID(node));
1583         REQUIRE(rootp != NULL);
1584
1585         child = RIGHT(node);
1586         INSIST(child != NULL);
1587
1588         RIGHT(node) = LEFT(child);
1589         if (LEFT(child) != NULL)
1590                 PARENT(LEFT(child)) = node;
1591         LEFT(child) = node;
1592
1593         if (child != NULL)
1594                 PARENT(child) = PARENT(node);
1595
1596         if (IS_ROOT(node)) {
1597                 *rootp = child;
1598                 child->is_root = 1;
1599                 node->is_root = 0;
1600
1601         } else {
1602                 if (LEFT(PARENT(node)) == node)
1603                         LEFT(PARENT(node)) = child;
1604                 else
1605                         RIGHT(PARENT(node)) = child;
1606         }
1607
1608         PARENT(node) = child;
1609 }
1610
1611 static inline void
1612 rotate_right(dns_rbtnode_t *node, dns_rbtnode_t **rootp) {
1613         dns_rbtnode_t *child;
1614
1615         REQUIRE(DNS_RBTNODE_VALID(node));
1616         REQUIRE(rootp != NULL);
1617
1618         child = LEFT(node);
1619         INSIST(child != NULL);
1620
1621         LEFT(node) = RIGHT(child);
1622         if (RIGHT(child) != NULL)
1623                 PARENT(RIGHT(child)) = node;
1624         RIGHT(child) = node;
1625
1626         if (child != NULL)
1627                 PARENT(child) = PARENT(node);
1628
1629         if (IS_ROOT(node)) {
1630                 *rootp = child;
1631                 child->is_root = 1;
1632                 node->is_root = 0;
1633
1634         } else {
1635                 if (LEFT(PARENT(node)) == node)
1636                         LEFT(PARENT(node)) = child;
1637                 else
1638                         RIGHT(PARENT(node)) = child;
1639         }
1640
1641         PARENT(node) = child;
1642 }
1643
1644 /*
1645  * This is the real workhorse of the insertion code, because it does the
1646  * true red/black tree on a single level.
1647  */
1648 static void
1649 dns_rbt_addonlevel(dns_rbtnode_t *node, dns_rbtnode_t *current, int order,
1650                    dns_rbtnode_t **rootp)
1651 {
1652         dns_rbtnode_t *child, *root, *parent, *grandparent;
1653         dns_name_t add_name, current_name;
1654         dns_offsets_t add_offsets, current_offsets;
1655
1656         REQUIRE(rootp != NULL);
1657         REQUIRE(DNS_RBTNODE_VALID(node) && LEFT(node) == NULL &&
1658                 RIGHT(node) == NULL);
1659         REQUIRE(current != NULL);
1660
1661         root = *rootp;
1662         if (root == NULL) {
1663                 /*
1664                  * First node of a level.
1665                  */
1666                 MAKE_BLACK(node);
1667                 node->is_root = 1;
1668                 PARENT(node) = current;
1669                 *rootp = node;
1670                 return;
1671         }
1672
1673         child = root;
1674
1675         dns_name_init(&add_name, add_offsets);
1676         NODENAME(node, &add_name);
1677
1678         dns_name_init(&current_name, current_offsets);
1679         NODENAME(current, &current_name);
1680
1681         if (order < 0) {
1682                 INSIST(LEFT(current) == NULL);
1683                 LEFT(current) = node;
1684         } else {
1685                 INSIST(RIGHT(current) == NULL);
1686                 RIGHT(current) = node;
1687         }
1688
1689         INSIST(PARENT(node) == NULL);
1690         PARENT(node) = current;
1691
1692         MAKE_RED(node);
1693
1694         while (node != root && IS_RED(PARENT(node))) {
1695                 /*
1696                  * XXXDCL could do away with separate parent and grandparent
1697                  * variables.  They are vestiges of the days before parent
1698                  * pointers.  However, they make the code a little clearer.
1699                  */
1700
1701                 parent = PARENT(node);
1702                 grandparent = PARENT(parent);
1703
1704                 if (parent == LEFT(grandparent)) {
1705                         child = RIGHT(grandparent);
1706                         if (child != NULL && IS_RED(child)) {
1707                                 MAKE_BLACK(parent);
1708                                 MAKE_BLACK(child);
1709                                 MAKE_RED(grandparent);
1710                                 node = grandparent;
1711                         } else {
1712                                 if (node == RIGHT(parent)) {
1713                                         rotate_left(parent, &root);
1714                                         node = parent;
1715                                         parent = PARENT(node);
1716                                         grandparent = PARENT(parent);
1717                                 }
1718                                 MAKE_BLACK(parent);
1719                                 MAKE_RED(grandparent);
1720                                 rotate_right(grandparent, &root);
1721                         }
1722                 } else {
1723                         child = LEFT(grandparent);
1724                         if (child != NULL && IS_RED(child)) {
1725                                 MAKE_BLACK(parent);
1726                                 MAKE_BLACK(child);
1727                                 MAKE_RED(grandparent);
1728                                 node = grandparent;
1729                         } else {
1730                                 if (node == LEFT(parent)) {
1731                                         rotate_right(parent, &root);
1732                                         node = parent;
1733                                         parent = PARENT(node);
1734                                         grandparent = PARENT(parent);
1735                                 }
1736                                 MAKE_BLACK(parent);
1737                                 MAKE_RED(grandparent);
1738                                 rotate_left(grandparent, &root);
1739                         }
1740                 }
1741         }
1742
1743         MAKE_BLACK(root);
1744         ENSURE(IS_ROOT(root));
1745         *rootp = root;
1746
1747         return;
1748 }
1749
1750 /*
1751  * This is the real workhorse of the deletion code, because it does the
1752  * true red/black tree on a single level.
1753  */
1754 static void
1755 dns_rbt_deletefromlevel(dns_rbtnode_t *delete, dns_rbtnode_t **rootp) {
1756         dns_rbtnode_t *child, *sibling, *parent;
1757         dns_rbtnode_t *successor;
1758
1759         REQUIRE(delete != NULL);
1760
1761         /*
1762          * Verify that the parent history is (apparently) correct.
1763          */
1764         INSIST((IS_ROOT(delete) && *rootp == delete) ||
1765                (! IS_ROOT(delete) &&
1766                 (LEFT(PARENT(delete)) == delete ||
1767                  RIGHT(PARENT(delete)) == delete)));
1768
1769         child = NULL;
1770
1771         if (LEFT(delete) == NULL) {
1772                 if (RIGHT(delete) == NULL) {
1773                         if (IS_ROOT(delete)) {
1774                                 /*
1775                                  * This is the only item in the tree.
1776                                  */
1777                                 *rootp = NULL;
1778                                 return;
1779                         }
1780                 } else
1781                         /*
1782                          * This node has one child, on the right.
1783                          */
1784                         child = RIGHT(delete);
1785
1786         } else if (RIGHT(delete) == NULL)
1787                 /*
1788                  * This node has one child, on the left.
1789                  */
1790                 child = LEFT(delete);
1791         else {
1792                 dns_rbtnode_t holder, *tmp = &holder;
1793
1794                 /*
1795                  * This node has two children, so it cannot be directly
1796                  * deleted.  Find its immediate in-order successor and
1797                  * move it to this location, then do the deletion at the
1798                  * old site of the successor.
1799                  */
1800                 successor = RIGHT(delete);
1801                 while (LEFT(successor) != NULL)
1802                         successor = LEFT(successor);
1803
1804                 /*
1805                  * The successor cannot possibly have a left child;
1806                  * if there is any child, it is on the right.
1807                  */
1808                 if (RIGHT(successor) != NULL)
1809                         child = RIGHT(successor);
1810
1811                 /*
1812                  * Swap the two nodes; it would be simpler to just replace
1813                  * the value being deleted with that of the successor,
1814                  * but this rigamarole is done so the caller has complete
1815                  * control over the pointers (and memory allocation) of
1816                  * all of nodes.  If just the key value were removed from
1817                  * the tree, the pointer to the node would be unchanged.
1818                  */
1819
1820                 /*
1821                  * First, put the successor in the tree location of the
1822                  * node to be deleted.  Save its existing tree pointer
1823                  * information, which will be needed when linking up
1824                  * delete to the successor's old location.
1825                  */
1826                 memcpy(tmp, successor, sizeof(dns_rbtnode_t));
1827
1828                 if (IS_ROOT(delete)) {
1829                         *rootp = successor;
1830                         successor->is_root = ISC_TRUE;
1831                         delete->is_root = ISC_FALSE;
1832
1833                 } else
1834                         if (LEFT(PARENT(delete)) == delete)
1835                                 LEFT(PARENT(delete)) = successor;
1836                         else
1837                                 RIGHT(PARENT(delete)) = successor;
1838
1839                 PARENT(successor) = PARENT(delete);
1840                 LEFT(successor)   = LEFT(delete);
1841                 RIGHT(successor)  = RIGHT(delete);
1842                 COLOR(successor)  = COLOR(delete);
1843
1844                 if (LEFT(successor) != NULL)
1845                         PARENT(LEFT(successor)) = successor;
1846                 if (RIGHT(successor) != successor)
1847                         PARENT(RIGHT(successor)) = successor;
1848
1849                 /*
1850                  * Now relink the node to be deleted into the
1851                  * successor's previous tree location.  PARENT(tmp)
1852                  * is the successor's original parent.
1853                  */
1854                 INSIST(! IS_ROOT(delete));
1855
1856                 if (PARENT(tmp) == delete) {
1857                         /*
1858                          * Node being deleted was successor's parent.
1859                          */
1860                         RIGHT(successor) = delete;
1861                         PARENT(delete) = successor;
1862
1863                 } else {
1864                         LEFT(PARENT(tmp)) = delete;
1865                         PARENT(delete) = PARENT(tmp);
1866                 }
1867
1868                 /*
1869                  * Original location of successor node has no left.
1870                  */
1871                 LEFT(delete)   = NULL;
1872                 RIGHT(delete)  = RIGHT(tmp);
1873                 COLOR(delete)  = COLOR(tmp);
1874         }
1875
1876         /*
1877          * Remove the node by removing the links from its parent.
1878          */
1879         if (! IS_ROOT(delete)) {
1880                 if (LEFT(PARENT(delete)) == delete)
1881                         LEFT(PARENT(delete)) = child;
1882                 else
1883                         RIGHT(PARENT(delete)) = child;
1884
1885                 if (child != NULL)
1886                         PARENT(child) = PARENT(delete);
1887
1888         } else {
1889                 /*
1890                  * This is the root being deleted, and at this point
1891                  * it is known to have just one child.
1892                  */
1893                 *rootp = child;
1894                 child->is_root = 1;
1895                 PARENT(child) = PARENT(delete);
1896         }
1897
1898         /*
1899          * Fix color violations.
1900          */
1901         if (IS_BLACK(delete)) {
1902                 parent = PARENT(delete);
1903
1904                 while (child != *rootp && IS_BLACK(child)) {
1905                         INSIST(child == NULL || ! IS_ROOT(child));
1906
1907                         if (LEFT(parent) == child) {
1908                                 sibling = RIGHT(parent);
1909
1910                                 if (IS_RED(sibling)) {
1911                                         MAKE_BLACK(sibling);
1912                                         MAKE_RED(parent);
1913                                         rotate_left(parent, rootp);
1914                                         sibling = RIGHT(parent);
1915                                 }
1916
1917                                 if (IS_BLACK(LEFT(sibling)) &&
1918                                     IS_BLACK(RIGHT(sibling))) {
1919                                         MAKE_RED(sibling);
1920                                         child = parent;
1921
1922                                 } else {
1923
1924                                         if (IS_BLACK(RIGHT(sibling))) {
1925                                                 MAKE_BLACK(LEFT(sibling));
1926                                                 MAKE_RED(sibling);
1927                                                 rotate_right(sibling, rootp);
1928                                                 sibling = RIGHT(parent);
1929                                         }
1930
1931                                         COLOR(sibling) = COLOR(parent);
1932                                         MAKE_BLACK(parent);
1933                                         MAKE_BLACK(RIGHT(sibling));
1934                                         rotate_left(parent, rootp);
1935                                         child = *rootp;
1936                                 }
1937
1938                         } else {
1939                                 /*
1940                                  * Child is parent's right child.
1941                                  * Everything is done the same as above,
1942                                  * except mirrored.
1943                                  */
1944                                 sibling = LEFT(parent);
1945
1946                                 if (IS_RED(sibling)) {
1947                                         MAKE_BLACK(sibling);
1948                                         MAKE_RED(parent);
1949                                         rotate_right(parent, rootp);
1950                                         sibling = LEFT(parent);
1951                                 }
1952
1953                                 if (IS_BLACK(LEFT(sibling)) &&
1954                                     IS_BLACK(RIGHT(sibling))) {
1955                                         MAKE_RED(sibling);
1956                                         child = parent;
1957
1958                                 } else {
1959                                         if (IS_BLACK(LEFT(sibling))) {
1960                                                 MAKE_BLACK(RIGHT(sibling));
1961                                                 MAKE_RED(sibling);
1962                                                 rotate_left(sibling, rootp);
1963                                                 sibling = LEFT(parent);
1964                                         }
1965
1966                                         COLOR(sibling) = COLOR(parent);
1967                                         MAKE_BLACK(parent);
1968                                         MAKE_BLACK(LEFT(sibling));
1969                                         rotate_right(parent, rootp);
1970                                         child = *rootp;
1971                                 }
1972                         }
1973
1974                         parent = PARENT(child);
1975                 }
1976
1977                 if (IS_RED(child))
1978                         MAKE_BLACK(child);
1979         }
1980 }
1981
1982 /*
1983  * This should only be used on the root of a tree, because no color fixup
1984  * is done at all.
1985  *
1986  * NOTE: No root pointer maintenance is done, because the function is only
1987  * used for two cases:
1988  * + deleting everything DOWN from a node that is itself being deleted, and
1989  * + deleting the entire tree of trees from dns_rbt_destroy.
1990  * In each case, the root pointer is no longer relevant, so there
1991  * is no need for a root parameter to this function.
1992  *
1993  * If the function is ever intended to be used to delete something where
1994  * a pointer needs to be told that this tree no longer exists,
1995  * this function would need to adjusted accordingly.
1996  */
1997 static isc_result_t
1998 dns_rbt_deletetree(dns_rbt_t *rbt, dns_rbtnode_t *node) {
1999         isc_result_t result = ISC_R_SUCCESS;
2000         REQUIRE(VALID_RBT(rbt));
2001
2002         if (node == NULL)
2003                 return (result);
2004
2005         if (LEFT(node) != NULL) {
2006                 result = dns_rbt_deletetree(rbt, LEFT(node));
2007                 if (result != ISC_R_SUCCESS)
2008                         goto done;
2009                 LEFT(node) = NULL;
2010         }
2011         if (RIGHT(node) != NULL) {
2012                 result = dns_rbt_deletetree(rbt, RIGHT(node));
2013                 if (result != ISC_R_SUCCESS)
2014                         goto done;
2015                 RIGHT(node) = NULL;
2016         }
2017         if (DOWN(node) != NULL) {
2018                 result = dns_rbt_deletetree(rbt, DOWN(node));
2019                 if (result != ISC_R_SUCCESS)
2020                         goto done;
2021                 DOWN(node) = NULL;
2022         }
2023  done:
2024         if (result != ISC_R_SUCCESS)
2025                 return (result);
2026
2027         if (DATA(node) != NULL && rbt->data_deleter != NULL)
2028                 rbt->data_deleter(DATA(node), rbt->deleter_arg);
2029
2030         unhash_node(rbt, node);
2031 #if DNS_RBT_USEMAGIC
2032         node->magic = 0;
2033 #endif
2034
2035         isc_mem_put(rbt->mctx, node, NODE_SIZE(node));
2036         rbt->nodecount--;
2037         return (result);
2038 }
2039
2040 static void
2041 dns_rbt_deletetreeflat(dns_rbt_t *rbt, unsigned int quantum,
2042                        dns_rbtnode_t **nodep)
2043 {
2044         dns_rbtnode_t *parent;
2045         dns_rbtnode_t *node = *nodep;
2046         REQUIRE(VALID_RBT(rbt));
2047
2048  again:
2049         if (node == NULL) {
2050                 *nodep = NULL;
2051                 return;
2052         }
2053
2054  traverse:
2055         if (LEFT(node) != NULL) {
2056                 node = LEFT(node);
2057                 goto traverse;
2058         }
2059         if (DOWN(node) != NULL) {
2060                 node = DOWN(node);
2061                 goto traverse;
2062         }
2063
2064         if (DATA(node) != NULL && rbt->data_deleter != NULL)
2065                 rbt->data_deleter(DATA(node), rbt->deleter_arg);
2066
2067         /*
2068          * Note: we don't call unhash_node() here as we are destroying
2069          * the complete rbt tree.
2070          */
2071 #if DNS_RBT_USEMAGIC
2072         node->magic = 0;
2073 #endif
2074         parent = PARENT(node);
2075         if (RIGHT(node) != NULL)
2076                 PARENT(RIGHT(node)) = parent;
2077         if (parent != NULL) {
2078                 if (LEFT(parent) == node)
2079                         LEFT(parent) = RIGHT(node);
2080                 else if (DOWN(parent) == node)
2081                         DOWN(parent) = RIGHT(node);
2082         } else
2083                 parent = RIGHT(node);
2084
2085         isc_mem_put(rbt->mctx, node, NODE_SIZE(node));
2086         rbt->nodecount--;
2087         node = parent;
2088         if (quantum != 0 && --quantum == 0) {
2089                 *nodep = node;
2090                 return;
2091         }
2092         goto again;
2093 }
2094
2095 static void
2096 dns_rbt_indent(int depth) {
2097         int i;
2098
2099         for (i = 0; i < depth; i++)
2100                 putchar('\t');
2101 }
2102
2103 static void
2104 dns_rbt_printnodename(dns_rbtnode_t *node) {
2105         isc_region_t r;
2106         dns_name_t name;
2107         char buffer[DNS_NAME_FORMATSIZE];
2108         dns_offsets_t offsets;
2109
2110         r.length = NAMELEN(node);
2111         r.base = NAME(node);
2112
2113         dns_name_init(&name, offsets);
2114         dns_name_fromregion(&name, &r);
2115
2116         dns_name_format(&name, buffer, sizeof(buffer));
2117
2118         printf("%s", buffer);
2119 }
2120
2121 static void
2122 dns_rbt_printtree(dns_rbtnode_t *root, dns_rbtnode_t *parent, int depth) {
2123         dns_rbt_indent(depth);
2124
2125         if (root != NULL) {
2126                 dns_rbt_printnodename(root);
2127                 printf(" (%s", IS_RED(root) ? "RED" : "black");
2128                 if (parent) {
2129                         printf(" from ");
2130                         dns_rbt_printnodename(parent);
2131                 }
2132
2133                 if ((! IS_ROOT(root) && PARENT(root) != parent) ||
2134                     (  IS_ROOT(root) && depth > 0 &&
2135                        DOWN(PARENT(root)) != root)) {
2136
2137                         printf(" (BAD parent pointer! -> ");
2138                         if (PARENT(root) != NULL)
2139                                 dns_rbt_printnodename(PARENT(root));
2140                         else
2141                                 printf("NULL");
2142                         printf(")");
2143                 }
2144
2145                 printf(")\n");
2146
2147
2148                 depth++;
2149
2150                 if (DOWN(root)) {
2151                         dns_rbt_indent(depth);
2152                         printf("++ BEG down from ");
2153                         dns_rbt_printnodename(root);
2154                         printf("\n");
2155                         dns_rbt_printtree(DOWN(root), NULL, depth);
2156                         dns_rbt_indent(depth);
2157                         printf("-- END down from ");
2158                         dns_rbt_printnodename(root);
2159                         printf("\n");
2160                 }
2161
2162                 if (IS_RED(root) && IS_RED(LEFT(root)))
2163                     printf("** Red/Red color violation on left\n");
2164                 dns_rbt_printtree(LEFT(root), root, depth);
2165
2166                 if (IS_RED(root) && IS_RED(RIGHT(root)))
2167                     printf("** Red/Red color violation on right\n");
2168                 dns_rbt_printtree(RIGHT(root), root, depth);
2169
2170         } else
2171                 printf("NULL\n");
2172 }
2173
2174 void
2175 dns_rbt_printall(dns_rbt_t *rbt) {
2176         REQUIRE(VALID_RBT(rbt));
2177
2178         dns_rbt_printtree(rbt->root, NULL, 0);
2179 }
2180
2181 /*
2182  * Chain Functions
2183  */
2184
2185 void
2186 dns_rbtnodechain_init(dns_rbtnodechain_t *chain, isc_mem_t *mctx) {
2187         /*
2188          * Initialize 'chain'.
2189          */
2190
2191         REQUIRE(chain != NULL);
2192
2193         chain->mctx = mctx;
2194         chain->end = NULL;
2195         chain->level_count = 0;
2196         chain->level_matches = 0;
2197         memset(chain->levels, 0, sizeof(chain->levels));
2198
2199         chain->magic = CHAIN_MAGIC;
2200 }
2201
2202 isc_result_t
2203 dns_rbtnodechain_current(dns_rbtnodechain_t *chain, dns_name_t *name,
2204                          dns_name_t *origin, dns_rbtnode_t **node)
2205 {
2206         isc_result_t result = ISC_R_SUCCESS;
2207
2208         REQUIRE(VALID_CHAIN(chain));
2209
2210         if (node != NULL)
2211                 *node = chain->end;
2212
2213         if (chain->end == NULL)
2214                 return (ISC_R_NOTFOUND);
2215
2216         if (name != NULL) {
2217                 NODENAME(chain->end, name);
2218
2219                 if (chain->level_count == 0) {
2220                         /*
2221                          * Names in the top level tree are all absolute.
2222                          * Always make 'name' relative.
2223                          */
2224                         INSIST(dns_name_isabsolute(name));
2225
2226                         /*
2227                          * This is cheaper than dns_name_getlabelsequence().
2228                          */
2229                         name->labels--;
2230                         name->length--;
2231                         name->attributes &= ~DNS_NAMEATTR_ABSOLUTE;
2232                 }
2233         }
2234
2235         if (origin != NULL) {
2236                 if (chain->level_count > 0)
2237                         result = chain_name(chain, origin, ISC_FALSE);
2238                 else
2239                         result = dns_name_copy(dns_rootname, origin, NULL);
2240         }
2241
2242         return (result);
2243 }
2244
2245 isc_result_t
2246 dns_rbtnodechain_prev(dns_rbtnodechain_t *chain, dns_name_t *name,
2247                       dns_name_t *origin)
2248 {
2249         dns_rbtnode_t *current, *previous, *predecessor;
2250         isc_result_t result = ISC_R_SUCCESS;
2251         isc_boolean_t new_origin = ISC_FALSE;
2252
2253         REQUIRE(VALID_CHAIN(chain) && chain->end != NULL);
2254
2255         predecessor = NULL;
2256
2257         current = chain->end;
2258
2259         if (LEFT(current) != NULL) {
2260                 /*
2261                  * Moving left one then right as far as possible is the
2262                  * previous node, at least for this level.
2263                  */
2264                 current = LEFT(current);
2265
2266                 while (RIGHT(current) != NULL)
2267                         current = RIGHT(current);
2268
2269                 predecessor = current;
2270
2271         } else {
2272                 /*
2273                  * No left links, so move toward the root.  If at any point on
2274                  * the way there the link from parent to child is a right
2275                  * link, then the parent is the previous node, at least
2276                  * for this level.
2277                  */
2278                 while (! IS_ROOT(current)) {
2279                         previous = current;
2280                         current = PARENT(current);
2281
2282                         if (RIGHT(current) == previous) {
2283                                 predecessor = current;
2284                                 break;
2285                         }
2286                 }
2287         }
2288
2289         if (predecessor != NULL) {
2290                 /*
2291                  * Found a predecessor node in this level.  It might not
2292                  * really be the predecessor, however.
2293                  */
2294                 if (DOWN(predecessor) != NULL) {
2295                         /*
2296                          * The predecessor is really down at least one level.
2297                          * Go down and as far right as possible, and repeat
2298                          * as long as the rightmost node has a down pointer.
2299                          */
2300                         do {
2301                                 /*
2302                                  * XXX DCL Need to do something about origins
2303                                  * here. See whether to go down, and if so
2304                                  * whether it is truly what Bob calls a
2305                                  * new origin.
2306                                  */
2307                                 ADD_LEVEL(chain, predecessor);
2308                                 predecessor = DOWN(predecessor);
2309
2310                                 /* XXX DCL duplicated from above; clever
2311                                  * way to unduplicate? */
2312
2313                                 while (RIGHT(predecessor) != NULL)
2314                                         predecessor = RIGHT(predecessor);
2315                         } while (DOWN(predecessor) != NULL);
2316
2317                         /* XXX DCL probably needs work on the concept */
2318                         if (origin != NULL)
2319                                 new_origin = ISC_TRUE;
2320                 }
2321
2322         } else if (chain->level_count > 0) {
2323                 /*
2324                  * Dang, didn't find a predecessor in this level.
2325                  * Got to the root of this level without having traversed
2326                  * any right links.  Ascend the tree one level; the
2327                  * node that points to this tree is the predecessor.
2328                  */
2329                 INSIST(chain->level_count > 0 && IS_ROOT(current));
2330                 predecessor = chain->levels[--chain->level_count];
2331
2332                 /* XXX DCL probably needs work on the concept */
2333                 /*
2334                  * Don't declare an origin change when the new origin is "."
2335                  * at the top level tree, because "." is declared as the origin
2336                  * for the second level tree.
2337                  */
2338                 if (origin != NULL &&
2339                     (chain->level_count > 0 || OFFSETLEN(predecessor) > 1))
2340                         new_origin = ISC_TRUE;
2341         }
2342
2343         if (predecessor != NULL) {
2344                 chain->end = predecessor;
2345
2346                 if (new_origin) {
2347                         result = dns_rbtnodechain_current(chain, name, origin,
2348                                                           NULL);
2349                         if (result == ISC_R_SUCCESS)
2350                                 result = DNS_R_NEWORIGIN;
2351
2352                 } else
2353                         result = dns_rbtnodechain_current(chain, name, NULL,
2354                                                           NULL);
2355
2356         } else
2357                 result = ISC_R_NOMORE;
2358
2359         return (result);
2360 }
2361
2362 isc_result_t
2363 dns_rbtnodechain_next(dns_rbtnodechain_t *chain, dns_name_t *name,
2364                       dns_name_t *origin)
2365 {
2366         dns_rbtnode_t *current, *previous, *successor;
2367         isc_result_t result = ISC_R_SUCCESS;
2368         isc_boolean_t new_origin = ISC_FALSE;
2369
2370         REQUIRE(VALID_CHAIN(chain) && chain->end != NULL);
2371
2372         successor = NULL;
2373
2374         current = chain->end;
2375
2376         /*
2377          * If there is a level below this node, the next node is the leftmost
2378          * node of the next level.
2379          */
2380         if (DOWN(current) != NULL) {
2381                 /*
2382                  * Don't declare an origin change when the new origin is "."
2383                  * at the second level tree, because "." is already declared
2384                  * as the origin for the top level tree.
2385                  */
2386                 if (chain->level_count > 0 ||
2387                     OFFSETLEN(current) > 1)
2388                         new_origin = ISC_TRUE;
2389
2390                 ADD_LEVEL(chain, current);
2391                 current = DOWN(current);
2392
2393                 while (LEFT(current) != NULL)
2394                         current = LEFT(current);
2395
2396                 successor = current;
2397
2398         } else if (RIGHT(current) == NULL) {
2399                 /*
2400                  * The successor is up, either in this level or a previous one.
2401                  * Head back toward the root of the tree, looking for any path
2402                  * that was via a left link; the successor is the node that has
2403                  * that left link.  In the event the root of the level is
2404                  * reached without having traversed any left links, ascend one
2405                  * level and look for either a right link off the point of
2406                  * ascent, or search for a left link upward again, repeating
2407                  * ascends until either case is true.
2408                  */
2409                 do {
2410                         while (! IS_ROOT(current)) {
2411                                 previous = current;
2412                                 current = PARENT(current);
2413
2414                                 if (LEFT(current) == previous) {
2415                                         successor = current;
2416                                         break;
2417                                 }
2418                         }
2419
2420                         if (successor == NULL) {
2421                                 /*
2422                                  * Reached the root without having traversed
2423                                  * any left pointers, so this level is done.
2424                                  */
2425                                 if (chain->level_count == 0)
2426                                         break;
2427
2428                                 current = chain->levels[--chain->level_count];
2429                                 new_origin = ISC_TRUE;
2430
2431                                 if (RIGHT(current) != NULL)
2432                                         break;
2433                         }
2434                 } while (successor == NULL);
2435         }
2436
2437         if (successor == NULL && RIGHT(current) != NULL) {
2438                 current = RIGHT(current);
2439
2440                 while (LEFT(current) != NULL)
2441                         current = LEFT(current);
2442
2443                 successor = current;
2444         }
2445
2446         if (successor != NULL) {
2447                 chain->end = successor;
2448
2449                 /*
2450                  * It is not necessary to use dns_rbtnodechain_current like
2451                  * the other functions because this function will never
2452                  * find a node in the topmost level.  This is because the
2453                  * root level will never be more than one name, and everything
2454                  * in the megatree is a successor to that node, down at
2455                  * the second level or below.
2456                  */
2457
2458                 if (name != NULL)
2459                         NODENAME(chain->end, name);
2460
2461                 if (new_origin) {
2462                         if (origin != NULL)
2463                                 result = chain_name(chain, origin, ISC_FALSE);
2464
2465                         if (result == ISC_R_SUCCESS)
2466                                 result = DNS_R_NEWORIGIN;
2467
2468                 } else
2469                         result = ISC_R_SUCCESS;
2470
2471         } else
2472                 result = ISC_R_NOMORE;
2473
2474         return (result);
2475 }
2476
2477 isc_result_t
2478 dns_rbtnodechain_first(dns_rbtnodechain_t *chain, dns_rbt_t *rbt,
2479                        dns_name_t *name, dns_name_t *origin)
2480
2481 {
2482         isc_result_t result;
2483
2484         REQUIRE(VALID_RBT(rbt));
2485         REQUIRE(VALID_CHAIN(chain));
2486
2487         dns_rbtnodechain_reset(chain);
2488
2489         chain->end = rbt->root;
2490
2491         result = dns_rbtnodechain_current(chain, name, origin, NULL);
2492
2493         if (result == ISC_R_SUCCESS)
2494                 result = DNS_R_NEWORIGIN;
2495
2496         return (result);
2497 }
2498
2499 isc_result_t
2500 dns_rbtnodechain_last(dns_rbtnodechain_t *chain, dns_rbt_t *rbt,
2501                        dns_name_t *name, dns_name_t *origin)
2502
2503 {
2504         isc_result_t result;
2505
2506         REQUIRE(VALID_RBT(rbt));
2507         REQUIRE(VALID_CHAIN(chain));
2508
2509         dns_rbtnodechain_reset(chain);
2510
2511         result = move_chain_to_last(chain, rbt->root);
2512         if (result != ISC_R_SUCCESS)
2513                 return (result);
2514
2515         result = dns_rbtnodechain_current(chain, name, origin, NULL);
2516
2517         if (result == ISC_R_SUCCESS)
2518                 result = DNS_R_NEWORIGIN;
2519
2520         return (result);
2521 }
2522
2523
2524 void
2525 dns_rbtnodechain_reset(dns_rbtnodechain_t *chain) {
2526         /*
2527          * Free any dynamic storage associated with 'chain', and then
2528          * reinitialize 'chain'.
2529          */
2530
2531         REQUIRE(VALID_CHAIN(chain));
2532
2533         chain->end = NULL;
2534         chain->level_count = 0;
2535         chain->level_matches = 0;
2536 }
2537
2538 void
2539 dns_rbtnodechain_invalidate(dns_rbtnodechain_t *chain) {
2540         /*
2541          * Free any dynamic storage associated with 'chain', and then
2542          * invalidate 'chain'.
2543          */
2544
2545         dns_rbtnodechain_reset(chain);
2546
2547         chain->magic = 0;
2548 }