/* * Copyright (C) 1999-2001, 2003 Internet Software Consortium. * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ /* $ISC: rbt.c,v 1.115.2.2 2003/07/22 04:03:42 marka Exp $ */ /* Principal Authors: DCL */ #include #include #include #include #include /* * This define is so dns/name.h (included by dns/fixedname.h) uses more * efficient macro calls instead of functions for a few operations. */ #define DNS_NAME_USEINLINE 1 #include #include #include #define RBT_MAGIC ISC_MAGIC('R', 'B', 'T', '+') #define VALID_RBT(rbt) ISC_MAGIC_VALID(rbt, RBT_MAGIC) /* * XXXDCL Since parent pointers were added in again, I could remove all of the * chain junk, and replace with dns_rbt_firstnode, _previousnode, _nextnode, * _lastnode. This would involve pretty major change to the API. */ #define CHAIN_MAGIC ISC_MAGIC('0', '-', '0', '-') #define VALID_CHAIN(chain) ISC_MAGIC_VALID(chain, CHAIN_MAGIC) #define RBT_HASH_SIZE 64 #ifdef RBT_MEM_TEST #undef RBT_HASH_SIZE #define RBT_HASH_SIZE 2 /* To give the reallocation code a workout. */ #endif struct dns_rbt { unsigned int magic; isc_mem_t * mctx; dns_rbtnode_t * root; void (*data_deleter)(void *, void *); void * deleter_arg; unsigned int nodecount; unsigned int hashsize; dns_rbtnode_t ** hashtable; }; #define RED 0 #define BLACK 1 /* * Elements of the rbtnode structure. */ #define PARENT(node) ((node)->parent) #define LEFT(node) ((node)->left) #define RIGHT(node) ((node)->right) #define DOWN(node) ((node)->down) #define DATA(node) ((node)->data) #define HASHNEXT(node) ((node)->hashnext) #define HASHVAL(node) ((node)->hashval) #define COLOR(node) ((node)->color) #define NAMELEN(node) ((node)->namelen) #define OFFSETLEN(node) ((node)->offsetlen) #define ATTRS(node) ((node)->attributes) #define PADBYTES(node) ((node)->padbytes) #define IS_ROOT(node) ISC_TF((node)->is_root == 1) #define FINDCALLBACK(node) ISC_TF((node)->find_callback == 1) /* * Structure elements from the rbtdb.c, not * used as part of the rbt.c algorithms. */ #define DIRTY(node) ((node)->dirty) #define WILD(node) ((node)->wild) #define LOCKNUM(node) ((node)->locknum) #define REFS(node) ((node)->references) /* * The variable length stuff stored after the node. */ #define NAME(node) ((unsigned char *)((node) + 1)) #define OFFSETS(node) (NAME(node) + NAMELEN(node)) #define NODE_SIZE(node) (sizeof(*node) + \ NAMELEN(node) + OFFSETLEN(node) + PADBYTES(node)) /* * Color management. */ #define IS_RED(node) ((node) != NULL && (node)->color == RED) #define IS_BLACK(node) ((node) == NULL || (node)->color == BLACK) #define MAKE_RED(node) ((node)->color = RED) #define MAKE_BLACK(node) ((node)->color = BLACK) /* * Chain management. * * The "ancestors" member of chains were removed, with their job now * being wholy handled by parent pointers (which didn't exist, because * of memory concerns, when chains were first implemented). */ #define ADD_LEVEL(chain, node) \ (chain)->levels[(chain)->level_count++] = (node) /* * The following macros directly access normally private name variables. * These macros are used to avoid a lot of function calls in the critical * path of the tree traversal code. */ #define NODENAME(node, name) \ do { \ (name)->length = NAMELEN(node); \ (name)->labels = OFFSETLEN(node); \ (name)->ndata = NAME(node); \ (name)->offsets = OFFSETS(node); \ (name)->attributes = ATTRS(node); \ (name)->attributes |= DNS_NAMEATTR_READONLY; \ } while (0) #ifdef DEBUG #define inline /* * A little something to help out in GDB. */ dns_name_t Name(dns_rbtnode_t *node); dns_name_t Name(dns_rbtnode_t *node) { dns_name_t name; dns_name_init(&name, NULL); if (node != NULL) NODENAME(node, &name); return (name); } static void dns_rbt_printnodename(dns_rbtnode_t *node); #endif static inline dns_rbtnode_t * find_up(dns_rbtnode_t *node) { dns_rbtnode_t *root; /* * Return the node in the level above the argument node that points * to the level the argument node is in. If the argument node is in * the top level, the return value is NULL. */ for (root = node; ! IS_ROOT(root); root = PARENT(root)) ; /* Nothing. */ return(PARENT(root)); } static inline unsigned int name_hash(dns_name_t *name) { unsigned int nlabels; unsigned int hash; dns_name_t tname; if (dns_name_countlabels(name) == 1) return (dns_name_hash(name, ISC_FALSE)); dns_name_init(&tname, NULL); nlabels = dns_name_countlabels(name); hash = 0; for ( ; nlabels > 0; nlabels--) { dns_name_getlabelsequence(name, nlabels - 1, 1, &tname); hash += dns_name_hash(&tname, ISC_FALSE); } return (hash); } #ifdef DNS_RBT_USEHASH static inline void compute_node_hash(dns_rbtnode_t *node) { unsigned int hash; dns_name_t name; dns_rbtnode_t *up_node; dns_name_init(&name, NULL); NODENAME(node, &name); hash = name_hash(&name); up_node = find_up(node); if (up_node != NULL) hash += HASHVAL(up_node); HASHVAL(node) = hash; } #endif /* * Forward declarations. */ static isc_result_t create_node(isc_mem_t *mctx, dns_name_t *name, dns_rbtnode_t **nodep); #ifdef DNS_RBT_USEHASH static inline isc_result_t hash_node(dns_rbt_t *rbt, dns_rbtnode_t *node); static inline void unhash_node(dns_rbt_t *rbt, dns_rbtnode_t *node); #else #define hash_node(rbt, node) (ISC_R_SUCCESS) #define unhash_node(rbt, node) #endif static inline void rotate_left(dns_rbtnode_t *node, dns_rbtnode_t **rootp); static inline void rotate_right(dns_rbtnode_t *node, dns_rbtnode_t **rootp); static void dns_rbt_addonlevel(dns_rbtnode_t *node, dns_rbtnode_t *current, int order, dns_rbtnode_t **rootp); static void dns_rbt_deletefromlevel(dns_rbtnode_t *delete, dns_rbtnode_t **rootp); static void dns_rbt_deletetree(dns_rbt_t *rbt, dns_rbtnode_t *node); /* * Initialize a red/black tree of trees. */ isc_result_t dns_rbt_create(isc_mem_t *mctx, void (*deleter)(void *, void *), void *deleter_arg, dns_rbt_t **rbtp) { dns_rbt_t *rbt; REQUIRE(mctx != NULL); REQUIRE(rbtp != NULL && *rbtp == NULL); REQUIRE(deleter == NULL ? deleter_arg == NULL : 1); rbt = (dns_rbt_t *)isc_mem_get(mctx, sizeof(*rbt)); if (rbt == NULL) return (ISC_R_NOMEMORY); rbt->mctx = mctx; rbt->data_deleter = deleter; rbt->deleter_arg = deleter_arg; rbt->root = NULL; rbt->nodecount = 0; rbt->hashtable = NULL; rbt->hashsize = 0; rbt->magic = RBT_MAGIC; *rbtp = rbt; return (ISC_R_SUCCESS); } /* * Deallocate a red/black tree of trees. */ void dns_rbt_destroy(dns_rbt_t **rbtp) { dns_rbt_t *rbt; REQUIRE(rbtp != NULL && VALID_RBT(*rbtp)); rbt = *rbtp; dns_rbt_deletetree(rbt, rbt->root); INSIST(rbt->nodecount == 0); if (rbt->hashtable != NULL) isc_mem_put(rbt->mctx, rbt->hashtable, rbt->hashsize * sizeof(dns_rbtnode_t *)); rbt->magic = 0; isc_mem_put(rbt->mctx, rbt, sizeof(*rbt)); *rbtp = NULL; } unsigned int dns_rbt_nodecount(dns_rbt_t *rbt) { REQUIRE(VALID_RBT(rbt)); return (rbt->nodecount); } static inline isc_result_t chain_name(dns_rbtnodechain_t *chain, dns_name_t *name, isc_boolean_t include_chain_end) { dns_name_t nodename; isc_result_t result = ISC_R_SUCCESS; int i; dns_name_init(&nodename, NULL); if (include_chain_end && chain->end != NULL) { NODENAME(chain->end, &nodename); result = dns_name_copy(&nodename, name, NULL); if (result != ISC_R_SUCCESS) return (result); } else dns_name_reset(name); for (i = (int)chain->level_count - 1; i >= 0; i--) { NODENAME(chain->levels[i], &nodename); result = dns_name_concatenate(name, &nodename, name, NULL); if (result != ISC_R_SUCCESS) return (result); } return (result); } static inline isc_result_t move_chain_to_last(dns_rbtnodechain_t *chain, dns_rbtnode_t *node) { do { /* * Go as far right and then down as much as possible, * as long as the rightmost node has a down pointer. */ while (RIGHT(node) != NULL) node = RIGHT(node); if (DOWN(node) == NULL) break; ADD_LEVEL(chain, node); node = DOWN(node); } while (1); chain->end = node; return (ISC_R_SUCCESS); } /* * Add 'name' to tree, initializing its data pointer with 'data'. */ isc_result_t dns_rbt_addnode(dns_rbt_t *rbt, dns_name_t *name, dns_rbtnode_t **nodep) { /* * Does this thing have too many variables or what? */ dns_rbtnode_t **root, *parent, *child, *current, *new_current; dns_name_t *add_name, current_name, *prefix, *suffix; dns_fixedname_t fixedcopy, fixedprefix, fixedsuffix; dns_offsets_t current_offsets; dns_namereln_t compared; isc_result_t result = ISC_R_SUCCESS; dns_rbtnodechain_t chain; unsigned int common_labels, common_bits, add_bits; int order; REQUIRE(VALID_RBT(rbt)); REQUIRE(dns_name_isabsolute(name)); REQUIRE(nodep != NULL && *nodep == NULL); /* * Create a copy of the name so the original name structure is * not modified. The name data needs to be modifiable when * a node is split on a bitstring label. */ dns_fixedname_init(&fixedcopy); add_name = dns_fixedname_name(&fixedcopy); dns_name_clone(name, add_name); if (rbt->root == NULL) { result = create_node(rbt->mctx, add_name, &new_current); if (result == ISC_R_SUCCESS) { rbt->nodecount++; new_current->is_root = 1; rbt->root = new_current; *nodep = new_current; result = hash_node(rbt, new_current); } return (result); } dns_rbtnodechain_init(&chain, rbt->mctx); dns_fixedname_init(&fixedprefix); dns_fixedname_init(&fixedsuffix); prefix = dns_fixedname_name(&fixedprefix); suffix = dns_fixedname_name(&fixedsuffix); root = &rbt->root; INSIST(IS_ROOT(*root)); parent = NULL; current = NULL; child = *root; dns_name_init(¤t_name, current_offsets); do { current = child; NODENAME(current, ¤t_name); compared = dns_name_fullcompare(add_name, ¤t_name, &order, &common_labels, &common_bits); if (compared == dns_namereln_equal) { *nodep = current; result = ISC_R_EXISTS; break; } if (compared == dns_namereln_none) { if (order < 0) { parent = current; child = LEFT(current); } else if (order > 0) { parent = current; child = RIGHT(current); } } else { /* * This name has some suffix in common with the * name at the current node. If the name at * the current node is shorter, that means the * new name should be in a subtree. If the * name at the current node is longer, that means * the down pointer to this tree should point * to a new tree that has the common suffix, and * the non-common parts of these two names should * start a new tree. */ if (compared == dns_namereln_subdomain) { /* * All of the existing labels are in common, * so the new name is in a subtree. * Whack off the common labels for the * not-in-common part to be searched for * in the next level. */ result = dns_name_split(add_name, common_labels, common_bits, add_name, NULL); if (result != ISC_R_SUCCESS) break; /* * Follow the down pointer (possibly NULL). */ root = &DOWN(current); INSIST(*root == NULL || (IS_ROOT(*root) && PARENT(*root) == current)); parent = NULL; child = DOWN(current); ADD_LEVEL(&chain, current); } else { /* * The number of labels in common is fewer * than the number of labels at the current * node, so the current node must be adjusted * to have just the common suffix, and a down * pointer made to a new tree. */ INSIST(compared == dns_namereln_commonancestor || compared == dns_namereln_contains); /* * Ensure the number of levels in the tree * does not exceed the number of logical * levels allowed by DNSSEC. * * XXXDCL need a better error result? * * XXXDCL Since chain ancestors were removed, * no longer used by dns_rbt_addonlevel(), * this is the only real use of chains in the * function. It could be done instead with * a simple integer variable, but I am pressed * for time. */ if (chain.level_count == (sizeof(chain.levels) / sizeof(*chain.levels))) { result = ISC_R_NOSPACE; break; } /* * Split the name into two parts, a prefix * which is the not-in-common parts of the * two names and a suffix that is the common * parts of them. */ result = dns_name_split(¤t_name, common_labels, common_bits, prefix, suffix); if (result == ISC_R_SUCCESS) result = create_node(rbt->mctx, suffix, &new_current); if (result != ISC_R_SUCCESS) break; /* * Reproduce the tree attributes of the * current node. */ new_current->is_root = current->is_root; PARENT(new_current) = PARENT(current); LEFT(new_current) = LEFT(current); RIGHT(new_current) = RIGHT(current); COLOR(new_current) = COLOR(current); /* * Fix pointers that were to the current node. */ if (parent != NULL) { if (LEFT(parent) == current) LEFT(parent) = new_current; else RIGHT(parent) = new_current; } if (LEFT(new_current) != NULL) PARENT(LEFT(new_current)) = new_current; if (RIGHT(new_current) != NULL) PARENT(RIGHT(new_current)) = new_current; if (*root == current) *root = new_current; /* * Now make the new root of the subtree * as the not-in-common labels of the current * node, keeping the same memory location so * as not to break any external references to * the node. The down pointer and name data * are preserved, while left and right * pointers are nullified when the node is * established as the start of the next level. * * The name stored at the node is effectively * truncated in place by setting the shorter * name length, moving the offsets to the * end of the truncated name, and then * updating PADBYTES to reflect the truncation. * * When bitstring labels are involved, things * are just a tad more complicated (aren't * they always?) because the splitting * has shifted the bits that this name needs * from the end of the label they were in * to either the beginning of the label or * even to the previous (lesser significance) * label if the split was done in a maximally * sized bitstring label. The bit count has * been adjusted too, so there are convolutions * to deal with all the bit movement. Yay, * I *love* bit labels. Grumble grumble. */ if (common_bits > 0) { unsigned char *p; unsigned int skip_width; unsigned int start_label = dns_name_countlabels(¤t_name) - common_labels; /* * If it is not the first label which * was split, also copy the label * before it -- which will essentially * be a NO-OP unless the preceding * label is a bitstring and the split * label was 256 bits. Testing for * that case is probably roughly * as expensive as just unconditionally * copying the preceding label. */ if (start_label > 0) start_label--; skip_width = prefix->offsets[start_label]; memcpy(NAME(current) + skip_width, prefix->ndata + skip_width, prefix->length - skip_width); /* * Now add_bits is set to the total * number of bits in the split label of * the name being added, and used later * to determine if the job was * completed by pushing the * not-in-common bits down one level. */ start_label = dns_name_countlabels(add_name) - common_labels; p = add_name->ndata + add_name->offsets[start_label]; INSIST(*p == DNS_LABELTYPE_BITSTRING); add_bits = *(p + 1); /* * A bitstring that was split would not * result in a part of maximal length. */ INSIST(add_bits != 0); } else add_bits = 0; NAMELEN(current) = prefix->length; OFFSETLEN(current) = prefix->labels; memcpy(OFFSETS(current), prefix->offsets, prefix->labels); PADBYTES(current) += (current_name.length - prefix->length) + (current_name.labels - prefix->labels); /* * Set up the new root of the next level. * By definition it will not be the top * level tree, so clear DNS_NAMEATTR_ABSOLUTE. */ current->is_root = 1; PARENT(current) = new_current; DOWN(new_current) = current; root = &DOWN(new_current); ADD_LEVEL(&chain, new_current); LEFT(current) = NULL; RIGHT(current) = NULL; MAKE_BLACK(current); ATTRS(current) &= ~DNS_NAMEATTR_ABSOLUTE; rbt->nodecount++; result = hash_node(rbt, new_current); if (result != ISC_R_SUCCESS) break; if (common_labels == dns_name_countlabels(add_name) && common_bits == add_bits) { /* * The name has been added by pushing * the not-in-common parts down to * a new level. */ *nodep = new_current; return (ISC_R_SUCCESS); } else { /* * The current node has no data, * because it is just a placeholder. * Its data pointer is already NULL * from create_node()), so there's * nothing more to do to it. */ /* * The not-in-common parts of the new * name will be inserted into the new * level following this loop (unless * result != ISC_R_SUCCESS, which * is tested after the loop ends). */ result = dns_name_split(add_name, common_labels, common_bits, add_name, NULL); break; } } } } while (child != NULL); if (result == ISC_R_SUCCESS) result = create_node(rbt->mctx, add_name, &new_current); if (result == ISC_R_SUCCESS) { dns_rbt_addonlevel(new_current, current, order, root); rbt->nodecount++; *nodep = new_current; result = hash_node(rbt, new_current); /* * XXXDCL Ugh. If hash_node failed, it was because * there is not enough memory. The node is now unfindable, * and ideally should be removed. This is kind of tricky, * and all hell is probably going to break loose throughout * the rest of the library because of the lack of memory, * so fixing up the tree as though no addition had been * made is skipped. (Actually, this hash_node failing is * not the only situation in this file where an unexpected * error can leave things in an incorrect state.) */ } return (result); } /* * Add a name to the tree of trees, associating it with some data. */ isc_result_t dns_rbt_addname(dns_rbt_t *rbt, dns_name_t *name, void *data) { isc_result_t result; dns_rbtnode_t *node; REQUIRE(VALID_RBT(rbt)); REQUIRE(dns_name_isabsolute(name)); node = NULL; result = dns_rbt_addnode(rbt, name, &node); /* * dns_rbt_addnode will report the node exists even when * it does not have data associated with it, but the * dns_rbt_*name functions all behave depending on whether * there is data associated with a node. */ if (result == ISC_R_SUCCESS || (result == ISC_R_EXISTS && DATA(node) == NULL)) { DATA(node) = data; result = ISC_R_SUCCESS; } return (result); } /* * Find the node for "name" in the tree of trees. */ isc_result_t dns_rbt_findnode(dns_rbt_t *rbt, dns_name_t *name, dns_name_t *foundname, dns_rbtnode_t **node, dns_rbtnodechain_t *chain, unsigned int options, dns_rbtfindcallback_t callback, void *callback_arg) { dns_rbtnode_t *current, *last_compared, *current_root; dns_rbtnodechain_t localchain; dns_name_t *search_name, current_name, *callback_name; dns_fixedname_t fixedcallbackname, fixedsearchname; dns_namereln_t compared; isc_result_t result, saved_result; unsigned int common_labels, common_bits; int order; REQUIRE(VALID_RBT(rbt)); REQUIRE(dns_name_isabsolute(name)); REQUIRE(node != NULL && *node == NULL); REQUIRE((options & (DNS_RBTFIND_NOEXACT | DNS_RBTFIND_NOPREDECESSOR)) != (DNS_RBTFIND_NOEXACT | DNS_RBTFIND_NOPREDECESSOR)); /* * If there is a chain it needs to appear to be in a sane state, * otherwise a chain is still needed to generate foundname and * callback_name. */ if (chain == NULL) { options |= DNS_RBTFIND_NOPREDECESSOR; chain = &localchain; dns_rbtnodechain_init(chain, rbt->mctx); } else dns_rbtnodechain_reset(chain); if (rbt->root == NULL) return (ISC_R_NOTFOUND); else { /* * Appease GCC about variables it incorrectly thinks are * possibly used unitialized. */ compared = dns_namereln_none; last_compared = NULL; } dns_fixedname_init(&fixedcallbackname); callback_name = dns_fixedname_name(&fixedcallbackname); /* * search_name is the name segment being sought in each tree level. * By using a fixedname, the search_name will definitely have offsets * and a buffer for use by any splitting that happens in the middle * of a bitstring label. By using dns_name_clone, no name data is * copied unless a bitstring split occurs. */ dns_fixedname_init(&fixedsearchname); search_name = dns_fixedname_name(&fixedsearchname); dns_name_clone(name, search_name); dns_name_init(¤t_name, NULL); saved_result = ISC_R_SUCCESS; current = rbt->root; current_root = rbt->root; while (current != NULL) { NODENAME(current, ¤t_name); compared = dns_name_fullcompare(search_name, ¤t_name, &order, &common_labels, &common_bits); last_compared = current; if (compared == dns_namereln_equal) break; if (compared == dns_namereln_none) { #ifdef DNS_RBT_USEHASH dns_name_t hash_name; dns_rbtnode_t *hnode; dns_rbtnode_t *up_current; unsigned int nlabels; unsigned int tlabels = 1; unsigned int hash; isc_boolean_t has_bitstring = ISC_FALSE; /* * If there is no hash table, hashing can't be done. * Similarly, when current != current_root, that * means a left or right pointer was followed, which * only happens when the algorithm fell through to * the traditional binary search because of a * bitstring label, so that traditional search * should be continued. */ if (rbt->hashtable == NULL || current != current_root) goto nohash; nlabels = dns_name_countlabels(search_name); /* * current_root is the root of the current level, so * it's parent is the same as it's "up" pointer. */ up_current = PARENT(current_root); dns_name_init(&hash_name, NULL); hashagain: dns_name_getlabelsequence(search_name, nlabels - tlabels, tlabels, &hash_name); hash = HASHVAL(up_current) + name_hash(&hash_name); for (hnode = rbt->hashtable[hash % rbt->hashsize]; hnode != NULL; hnode = hnode->hashnext) { dns_name_t hnode_name; if (hash != HASHVAL(hnode)) continue; if (find_up(hnode) != up_current) continue; dns_name_init(&hnode_name, NULL); NODENAME(hnode, &hnode_name); if (dns_name_equal(&hnode_name, &hash_name)) break; } if (hnode != NULL) { current = hnode; /* * This is an optimization. If hashing found * the right node, the next call to * dns_name_fullcompare() would obviously * return _equal or _subdomain. Determine * which of those would be the case by * checking if the full name was hashed. Then * make it look like dns_name_fullcompare * was called and jump to the right place. */ if (tlabels == nlabels) { compared = dns_namereln_equal; break; } else { common_labels = tlabels; common_bits = 0; compared = dns_namereln_subdomain; goto subdomain; } } /* * XXXDCL Bitstring labels complicate things, as usual. * Checking for the situation could be done up by the * dns_name_getlabelsequence so that they could still * use the hashing code, but it would be messy to * repeatedly try various bitstring lengths. Instead * just notice when a bitstring label is involved and * then punt to the traditional binary search if no * hash node is found after all of the labels are * tried. */ if (has_bitstring == ISC_FALSE && hash_name.ndata[0] == DNS_LABELTYPE_BITSTRING) has_bitstring = ISC_TRUE; if (tlabels++ < nlabels) goto hashagain; /* * All of the labels have been tried against the hash * table. If there wasn't a bitstring label involved, * the name isn't in the table. If there was, fall * through to the traditional search algorithm. */ if (! has_bitstring) { /* * Done with the search. */ current = NULL; continue; } /* FALLTHROUGH */ nohash: #endif /* DNS_RBT_USEHASH */ /* * Standard binary search tree movement. */ if (order < 0) current = LEFT(current); else current = RIGHT(current); } else { /* * The names have some common suffix labels. * * If the number in common are equal in length to * the current node's name length, then follow the * down pointer and search in the new tree. */ if (compared == dns_namereln_subdomain) { subdomain: /* * Whack off the current node's common parts * for the name to search in the next level. */ result = dns_name_split(search_name, common_labels, common_bits, search_name, NULL); if (result != ISC_R_SUCCESS) { dns_rbtnodechain_reset(chain); return (result); } /* * This might be the closest enclosing name. */ if (DATA(current) != NULL || (options & DNS_RBTFIND_EMPTYDATA) != 0) *node = current; /* * Point the chain to the next level. This * needs to be done before 'current' is pointed * there because the callback in the next * block of code needs the current 'current', * but in the event the callback requests that * the search be stopped then the * DNS_R_PARTIALMATCH code at the end of this * function needs the chain pointed to the * next level. */ ADD_LEVEL(chain, current); /* * The caller may want to interrupt the * downward search when certain special nodes * are traversed. If this is a special node, * the callback is used to learn what the * caller wants to do. */ if (callback != NULL && FINDCALLBACK(current)) { result = chain_name(chain, callback_name, ISC_FALSE); if (result != ISC_R_SUCCESS) { dns_rbtnodechain_reset(chain); return (result); } result = (callback)(current, callback_name, callback_arg); if (result != DNS_R_CONTINUE) { saved_result = result; /* * Treat this node as if it * had no down pointer. */ current = NULL; break; } } /* * Finally, head to the next tree level. */ current = DOWN(current); current_root = current; } else { /* * Though there are labels in common, the * entire name at this node is not common * with the search name so the search * name does not exist in the tree. */ INSIST(compared == dns_namereln_commonancestor || compared == dns_namereln_contains); current = NULL; } } } /* * If current is not NULL, NOEXACT is not disallowing exact matches, * and either the node has data or an empty node is ok, return * ISC_R_SUCCESS to indicate an exact match. */ if (current != NULL && (options & DNS_RBTFIND_NOEXACT) == 0 && (DATA(current) != NULL || (options & DNS_RBTFIND_EMPTYDATA) != 0)) { /* * Found an exact match. */ chain->end = current; chain->level_matches = chain->level_count; if (foundname != NULL) result = chain_name(chain, foundname, ISC_TRUE); else result = ISC_R_SUCCESS; if (result == ISC_R_SUCCESS) { *node = current; result = saved_result; } else *node = NULL; } else { /* * Did not find an exact match (or did not want one). */ if (*node != NULL) { /* * ... but found a partially matching superdomain. * Unwind the chain to the partial match node * to set level_matches to the level above the node, * and then to derive the name. * * chain->level_count is guaranteed to be at least 1 * here because by definition of finding a superdomain, * the chain is pointed to at least the first subtree. */ chain->level_matches = chain->level_count - 1; while (chain->levels[chain->level_matches] != *node) { INSIST(chain->level_matches > 0); chain->level_matches--; } if (foundname != NULL) { unsigned int saved_count = chain->level_count; chain->level_count = chain->level_matches + 1; result = chain_name(chain, foundname, ISC_FALSE); chain->level_count = saved_count; } else result = ISC_R_SUCCESS; if (result == ISC_R_SUCCESS) result = DNS_R_PARTIALMATCH; } else result = ISC_R_NOTFOUND; if (current != NULL) { /* * There was an exact match but either * DNS_RBTFIND_NOEXACT was set, or * DNS_RBTFIND_EMPTYDATA was set and the node had no * data. A policy decision was made to set the * chain to the exact match, but this is subject * to change if it becomes apparent that something * else would be more useful. It is important that * this case is handled here, because the predecessor * setting code below assumes the match was not exact. */ INSIST(((options & DNS_RBTFIND_NOEXACT) != 0) || ((options & DNS_RBTFIND_EMPTYDATA) == 0 && DATA(current) == NULL)); chain->end = current; } else if ((options & DNS_RBTFIND_NOPREDECESSOR) != 0) { /* * Ensure the chain points nowhere. */ chain->end = NULL; } else { /* * Since there was no exact match, the chain argument * needs to be pointed at the DNSSEC predecessor of * the search name. */ if (compared == dns_namereln_subdomain) { /* * Attempted to follow a down pointer that was * NULL, which means the searched for name was * a subdomain of a terminal name in the tree. * Since there are no existing subdomains to * order against, the terminal name is the * predecessor. */ INSIST(chain->level_count > 0); INSIST(chain->level_matches < chain->level_count); chain->end = chain->levels[--chain->level_count]; } else { isc_result_t result2; /* * Point current to the node that stopped * the search. * * With the hashing modification that has been * added to the algorithm, the stop node of a * standard binary search is not known. So it * has to be found. There is probably a more * clever way of doing this. * * The assignment of current to NULL when * the relationship is *not* dns_namereln_none, * even though it later gets set to the same * last_compared anyway, is simply to not push * the while loop in one more level of * indentation. */ if (compared == dns_namereln_none) current = last_compared; else current = NULL; while (current != NULL) { NODENAME(current, ¤t_name); compared = dns_name_fullcompare( search_name, ¤t_name, &order, &common_labels, &common_bits); last_compared = current; /* * Standard binary search movement. */ if (order < 0) current = LEFT(current); else current = RIGHT(current); } current = last_compared; /* * Reached a point within a level tree that * positively indicates the name is not * present, but the stop node could be either * less than the desired name (order > 0) or * greater than the desired name (order < 0). * * If the stop node is less, it is not * necessarily the predecessor. If the stop * node has a down pointer, then the real * predecessor is at the end of a level below * (not necessarily the next level). * Move down levels until the rightmost node * does not have a down pointer. * * When the stop node is greater, it is * the successor. All the logic for finding * the predecessor is handily encapsulated * in dns_rbtnodechain_prev. In the event * that the search name is less than anything * else in the tree, the chain is reset. * XXX DCL What is the best way for the caller * to know that the search name has * no predecessor? */ if (order > 0) { if (DOWN(current) != NULL) { ADD_LEVEL(chain, current); result2 = move_chain_to_last(chain, DOWN(current)); if (result2 != ISC_R_SUCCESS) result = result2; } else /* * Ah, the pure and simple * case. The stop node is the * predecessor. */ chain->end = current; } else { INSIST(order < 0); chain->end = current; result2 = dns_rbtnodechain_prev(chain, NULL, NULL); if (result2 == ISC_R_SUCCESS || result2 == DNS_R_NEWORIGIN) ; /* Nothing. */ else if (result2 == ISC_R_NOMORE) /* * There is no predecessor. */ dns_rbtnodechain_reset(chain); else result = result2; } } } } return (result); } /* * Get the data pointer associated with 'name'. */ isc_result_t dns_rbt_findname(dns_rbt_t *rbt, dns_name_t *name, unsigned int options, dns_name_t *foundname, void **data) { dns_rbtnode_t *node = NULL; isc_result_t result; REQUIRE(data != NULL && *data == NULL); result = dns_rbt_findnode(rbt, name, foundname, &node, NULL, options, NULL, NULL); if (node != NULL && (DATA(node) != NULL || (options & DNS_RBTFIND_EMPTYDATA) != 0)) *data = DATA(node); else result = ISC_R_NOTFOUND; return (result); } /* * Delete a name from the tree of trees. */ isc_result_t dns_rbt_deletename(dns_rbt_t *rbt, dns_name_t *name, isc_boolean_t recurse) { dns_rbtnode_t *node = NULL; isc_result_t result; REQUIRE(VALID_RBT(rbt)); REQUIRE(dns_name_isabsolute(name)); /* * First, find the node. * * When searching, the name might not have an exact match: * consider a.b.a.com, b.b.a.com and c.b.a.com as the only * elements of a tree, which would make layer 1 a single * node tree of "b.a.com" and layer 2 a three node tree of * a, b, and c. Deleting a.com would find only a partial depth * match in the first layer. Should it be a requirement that * that the name to be deleted have data? For now, it is. * * ->dirty, ->locknum and ->references are ignored; they are * solely the province of rbtdb.c. */ result = dns_rbt_findnode(rbt, name, NULL, &node, NULL, DNS_RBTFIND_NOOPTIONS, NULL, NULL); if (result == ISC_R_SUCCESS) { if (DATA(node) != NULL) result = dns_rbt_deletenode(rbt, node, recurse); else result = ISC_R_NOTFOUND; } else if (result == DNS_R_PARTIALMATCH) result = ISC_R_NOTFOUND; return (result); } /* * Remove a node from the tree of trees. * * NOTE WELL: deletion is *not* symmetric with addition; that is, reversing * a sequence of additions to be deletions will not generally get the * tree back to the state it started in. For example, if the addition * of "b.c" caused the node "a.b.c" to be split, pushing "a" to its own level, * then the subsequent deletion of "b.c" will not cause "a" to be pulled up, * restoring "a.b.c". The RBT *used* to do this kind of rejoining, but it * turned out to be a bad idea because it could corrupt an active nodechain * that had "b.c" as one of its levels -- and the RBT has no idea what * nodechains are in use by callers, so it can't even *try* to helpfully * fix them up (which would probably be doomed to failure anyway). * * Similarly, it is possible to leave the tree in a state where a supposedly * deleted node still exists. The first case of this is obvious; take * the tree which has "b.c" on one level, pointing to "a". Now deleted "b.c". * It was just established in the previous paragraph why we can't pull "a" * back up to its parent level. But what happens when "a" then gets deleted? * "b.c" is left hanging around without data or children. This condition * is actually pretty easy to detect, but ... should it really be removed? * Is a chain pointing to it? An iterator? Who knows! (Note that the * references structure member cannot be looked at because it is private to * rbtdb.) This is ugly and makes me unhappy, but after hours of trying to * make it more aesthetically proper and getting nowhere, this is the way it * is going to stay until such time as it proves to be a *real* problem. * * Finally, for reference, note that the original routine that did node * joining was called join_nodes(). It has been excised, living now only * in the CVS history, but comments have been left behind that point to it just * in case someone wants to muck with this some more. * * The one positive aspect of all of this is that joining used to have a * case where it might fail. Without trying to join, now this function always * succeeds. It still returns isc_result_t, though, so the API wouldn't change. */ isc_result_t dns_rbt_deletenode(dns_rbt_t *rbt, dns_rbtnode_t *node, isc_boolean_t recurse) { dns_rbtnode_t *parent; REQUIRE(VALID_RBT(rbt)); REQUIRE(node != NULL); if (DOWN(node) != NULL) { if (recurse) dns_rbt_deletetree(rbt, DOWN(node)); else { if (DATA(node) != NULL && rbt->data_deleter != NULL) rbt->data_deleter(DATA(node), rbt->deleter_arg); DATA(node) = NULL; /* * Since there is at least one node below this one and * no recursion was requested, the deletion is * complete. The down node from this node might be all * by itself on a single level, so join_nodes() could * be used to collapse the tree (with all the caveats * of the comment at the start of this function). */ return (ISC_R_SUCCESS); } } /* * Note the node that points to the level of the node that is being * deleted. If the deleted node is the top level, parent will be set * to NULL. */ parent = find_up(node); /* * This node now has no down pointer (either because it didn't * have one to start, or because it was recursively removed). * So now the node needs to be removed from this level. */ dns_rbt_deletefromlevel(node, parent == NULL ? &rbt->root : &DOWN(parent)); if (DATA(node) != NULL && rbt->data_deleter != NULL) rbt->data_deleter(DATA(node), rbt->deleter_arg); unhash_node(rbt, node); isc_mem_put(rbt->mctx, node, NODE_SIZE(node)); rbt->nodecount--; /* * There are now two special cases that can exist that would * not have existed if the tree had been created using only * the names that now exist in it. (This is all related to * join_nodes() as described in this function's introductory comment.) * Both cases exist when the deleted node's parent (the node * that pointed to the deleted node's level) is not null but * it has no data: parent != NULL && DATA(parent) == NULL. * * The first case is that the deleted node was the last on its level: * DOWN(parent) == NULL. This case can only exist if the parent was * previously deleted -- and so now, apparently, the parent should go * away. That can't be done though because there might be external * references to it, such as through a nodechain. * * The other case also involves a parent with no data, but with the * deleted node being the next-to-last node instead of the last: * LEFT(DOWN(parent)) == NULL && RIGHT(DOWN(parent)) == NULL. * Presumably now the remaining node on the level should be joined * with the parent, but it's already been described why that can't be * done. */ /* * This function never fails. */ return (ISC_R_SUCCESS); } void dns_rbt_namefromnode(dns_rbtnode_t *node, dns_name_t *name) { REQUIRE(node != NULL); REQUIRE(name != NULL); REQUIRE(name->offsets == NULL); NODENAME(node, name); } isc_result_t dns_rbt_fullnamefromnode(dns_rbtnode_t *node, dns_name_t *name) { dns_name_t current; isc_result_t result; REQUIRE(node != NULL); REQUIRE(name != NULL); REQUIRE(name->buffer != NULL); dns_name_init(¤t, NULL); dns_name_reset(name); do { INSIST(node != NULL); NODENAME(node, ¤t); result = dns_name_concatenate(name, ¤t, name, NULL); if (result != ISC_R_SUCCESS) break; node = find_up(node); } while (! dns_name_isabsolute(name)); return (result); } char * dns_rbt_formatnodename(dns_rbtnode_t *node, char *printname, unsigned int size) { dns_fixedname_t fixedname; dns_name_t *name; isc_result_t result; REQUIRE(node != NULL); REQUIRE(printname != NULL); dns_fixedname_init(&fixedname); name = dns_fixedname_name(&fixedname); result = dns_rbt_fullnamefromnode(node, name); if (result == ISC_R_SUCCESS) dns_name_format(name, printname, size); else snprintf(printname, size, "", dns_result_totext(result)); return (printname); } static isc_result_t create_node(isc_mem_t *mctx, dns_name_t *name, dns_rbtnode_t **nodep) { dns_rbtnode_t *node; isc_region_t region; unsigned int labels; REQUIRE(name->offsets != NULL); dns_name_toregion(name, ®ion); labels = dns_name_countlabels(name); ENSURE(labels > 0); /* * Allocate space for the node structure, the name, and the offsets. */ node = (dns_rbtnode_t *)isc_mem_get(mctx, sizeof(*node) + region.length + labels); if (node == NULL) return (ISC_R_NOMEMORY); node->is_root = 0; PARENT(node) = NULL; RIGHT(node) = NULL; LEFT(node) = NULL; DOWN(node) = NULL; DATA(node) = NULL; #ifdef DNS_RBT_USEHASH HASHNEXT(node) = NULL; HASHVAL(node) = 0; #endif LOCKNUM(node) = 0; REFS(node) = 0; WILD(node) = 0; DIRTY(node) = 0; node->find_callback = 0; MAKE_BLACK(node); /* * The following is stored to make reconstructing a name from the * stored value in the node easy: the length of the name, the number * of labels, whether the name is absolute or not, the name itself, * and the name's offsets table. * * XXX RTH * The offsets table could be made smaller by eliminating the * first offset, which is always 0. This requires changes to * lib/dns/name.c. */ NAMELEN(node) = region.length; PADBYTES(node) = 0; OFFSETLEN(node) = labels; ATTRS(node) = name->attributes; memcpy(NAME(node), region.base, region.length); memcpy(OFFSETS(node), name->offsets, labels); *nodep = node; return (ISC_R_SUCCESS); } #ifdef DNS_RBT_USEHASH static inline void hash_add_node(dns_rbt_t *rbt, dns_rbtnode_t *node) { unsigned int hash; compute_node_hash(node); hash = HASHVAL(node) % rbt->hashsize; HASHNEXT(node) = rbt->hashtable[hash]; rbt->hashtable[hash] = node; } static isc_result_t inithash(dns_rbt_t *rbt) { unsigned int bytes; rbt->hashsize = RBT_HASH_SIZE; bytes = rbt->hashsize * sizeof(dns_rbtnode_t *); rbt->hashtable = isc_mem_get(rbt->mctx, bytes); if (rbt->hashtable == NULL) return (ISC_R_NOMEMORY); memset(rbt->hashtable, 0, bytes); return (ISC_R_SUCCESS); } static isc_result_t rehash(dns_rbt_t *rbt) { unsigned int oldsize; dns_rbtnode_t **oldtable; dns_rbtnode_t *node; unsigned int hash; unsigned int i; oldsize = rbt->hashsize; rbt->hashsize *= 2; oldtable = rbt->hashtable; rbt->hashtable = isc_mem_get(rbt->mctx, rbt->hashsize * sizeof(dns_rbtnode_t *)); if (rbt->hashtable == NULL) return (ISC_R_NOMEMORY); for (i = 0; i < rbt->hashsize; i++) rbt->hashtable[i] = NULL; for (i = 0; i < oldsize; i++) { node = oldtable[i]; while (node != NULL) { hash = HASHVAL(node) % rbt->hashsize; oldtable[i] = HASHNEXT(node); HASHNEXT(node) = rbt->hashtable[hash]; rbt->hashtable[hash] = node; node = oldtable[i]; } } isc_mem_put(rbt->mctx, oldtable, rbt->hashsize * sizeof(dns_rbtnode_t *) / 2); return (ISC_R_SUCCESS); } static inline isc_result_t hash_node(dns_rbt_t *rbt, dns_rbtnode_t *node) { isc_result_t result = ISC_R_SUCCESS; if (rbt->hashtable == NULL) result = inithash(rbt); else if (rbt->nodecount >= rbt->hashsize) result = rehash(rbt); if (result == ISC_R_SUCCESS) hash_add_node(rbt, node); return (result); } static inline void unhash_node(dns_rbt_t *rbt, dns_rbtnode_t *node) { unsigned int bucket; dns_rbtnode_t *bucket_node; if (rbt->hashtable != NULL) { bucket = HASHVAL(node) % rbt->hashsize; bucket_node = rbt->hashtable[bucket]; if (bucket_node == node) rbt->hashtable[bucket] = HASHNEXT(node); else { while (HASHNEXT(bucket_node) != node) { INSIST(HASHNEXT(bucket_node) != NULL); bucket_node = HASHNEXT(bucket_node); } HASHNEXT(bucket_node) = HASHNEXT(node); } } } #endif /* DNS_RBT_USEHASH */ static inline void rotate_left(dns_rbtnode_t *node, dns_rbtnode_t **rootp) { dns_rbtnode_t *child; REQUIRE(node != NULL); REQUIRE(rootp != NULL); child = RIGHT(node); INSIST(child != NULL); RIGHT(node) = LEFT(child); if (LEFT(child) != NULL) PARENT(LEFT(child)) = node; LEFT(child) = node; if (child != NULL) PARENT(child) = PARENT(node); if (IS_ROOT(node)) { *rootp = child; child->is_root = 1; node->is_root = 0; } else { if (LEFT(PARENT(node)) == node) LEFT(PARENT(node)) = child; else RIGHT(PARENT(node)) = child; } PARENT(node) = child; } static inline void rotate_right(dns_rbtnode_t *node, dns_rbtnode_t **rootp) { dns_rbtnode_t *child; REQUIRE(node != NULL); REQUIRE(rootp != NULL); child = LEFT(node); INSIST(child != NULL); LEFT(node) = RIGHT(child); if (RIGHT(child) != NULL) PARENT(RIGHT(child)) = node; RIGHT(child) = node; if (child != NULL) PARENT(child) = PARENT(node); if (IS_ROOT(node)) { *rootp = child; child->is_root = 1; node->is_root = 0; } else { if (LEFT(PARENT(node)) == node) LEFT(PARENT(node)) = child; else RIGHT(PARENT(node)) = child; } PARENT(node) = child; } /* * This is the real workhorse of the insertion code, because it does the * true red/black tree on a single level. */ static void dns_rbt_addonlevel(dns_rbtnode_t *node, dns_rbtnode_t *current, int order, dns_rbtnode_t **rootp) { dns_rbtnode_t *child, *root, *parent, *grandparent; dns_name_t add_name, current_name; dns_offsets_t add_offsets, current_offsets; REQUIRE(rootp != NULL); REQUIRE(node != NULL && LEFT(node) == NULL && RIGHT(node) == NULL); REQUIRE(current != NULL); root = *rootp; if (root == NULL) { /* * First node of a level. */ MAKE_BLACK(node); node->is_root = 1; PARENT(node) = current; *rootp = node; return; } child = root; dns_name_init(&add_name, add_offsets); NODENAME(node, &add_name); dns_name_init(¤t_name, current_offsets); NODENAME(current, ¤t_name); if (order < 0) { INSIST(LEFT(current) == NULL); LEFT(current) = node; } else { INSIST(RIGHT(current) == NULL); RIGHT(current) = node; } INSIST(PARENT(node) == NULL); PARENT(node) = current; MAKE_RED(node); while (node != root && IS_RED(PARENT(node))) { /* * XXXDCL could do away with separate parent and grandparent * variables. They are vestiges of the days before parent * pointers. However, they make the code a little clearer. */ parent = PARENT(node); grandparent = PARENT(parent); if (parent == LEFT(grandparent)) { child = RIGHT(grandparent); if (child != NULL && IS_RED(child)) { MAKE_BLACK(parent); MAKE_BLACK(child); MAKE_RED(grandparent); node = grandparent; } else { if (node == RIGHT(parent)) { rotate_left(parent, &root); node = parent; parent = PARENT(node); grandparent = PARENT(parent); } MAKE_BLACK(parent); MAKE_RED(grandparent); rotate_right(grandparent, &root); } } else { child = LEFT(grandparent); if (child != NULL && IS_RED(child)) { MAKE_BLACK(parent); MAKE_BLACK(child); MAKE_RED(grandparent); node = grandparent; } else { if (node == LEFT(parent)) { rotate_right(parent, &root); node = parent; parent = PARENT(node); grandparent = PARENT(parent); } MAKE_BLACK(parent); MAKE_RED(grandparent); rotate_left(grandparent, &root); } } } MAKE_BLACK(root); ENSURE(IS_ROOT(root)); *rootp = root; return; } /* * This is the real workhorse of the deletion code, because it does the * true red/black tree on a single level. */ static void dns_rbt_deletefromlevel(dns_rbtnode_t *delete, dns_rbtnode_t **rootp) { dns_rbtnode_t *child, *sibling, *parent; dns_rbtnode_t *successor; REQUIRE(delete != NULL); /* * Verify that the parent history is (apparently) correct. */ INSIST((IS_ROOT(delete) && *rootp == delete) || (! IS_ROOT(delete) && (LEFT(PARENT(delete)) == delete || RIGHT(PARENT(delete)) == delete))); child = NULL; if (LEFT(delete) == NULL) { if (RIGHT(delete) == NULL) { if (IS_ROOT(delete)) { /* * This is the only item in the tree. */ *rootp = NULL; return; } } else /* * This node has one child, on the right. */ child = RIGHT(delete); } else if (RIGHT(delete) == NULL) /* * This node has one child, on the left. */ child = LEFT(delete); else { dns_rbtnode_t holder, *tmp = &holder; /* * This node has two children, so it cannot be directly * deleted. Find its immediate in-order successor and * move it to this location, then do the deletion at the * old site of the successor. */ successor = RIGHT(delete); while (LEFT(successor) != NULL) successor = LEFT(successor); /* * The successor cannot possibly have a left child; * if there is any child, it is on the right. */ if (RIGHT(successor) != NULL) child = RIGHT(successor); /* Swap the two nodes; it would be simpler to just replace * the value being deleted with that of the successor, * but this rigamarole is done so the caller has complete * control over the pointers (and memory allocation) of * all of nodes. If just the key value were removed from * the tree, the pointer to the node would be unchanged. */ /* * First, put the successor in the tree location of the * node to be deleted. Save its existing tree pointer * information, which will be needed when linking up * delete to the successor's old location. */ memcpy(tmp, successor, sizeof(dns_rbtnode_t)); if (IS_ROOT(delete)) { *rootp = successor; successor->is_root = ISC_TRUE; delete->is_root = ISC_FALSE; } else if (LEFT(PARENT(delete)) == delete) LEFT(PARENT(delete)) = successor; else RIGHT(PARENT(delete)) = successor; PARENT(successor) = PARENT(delete); LEFT(successor) = LEFT(delete); RIGHT(successor) = RIGHT(delete); COLOR(successor) = COLOR(delete); if (LEFT(successor) != NULL) PARENT(LEFT(successor)) = successor; if (RIGHT(successor) != successor) PARENT(RIGHT(successor)) = successor; /* * Now relink the node to be deleted into the * successor's previous tree location. PARENT(tmp) * is the successor's original parent. */ INSIST(! IS_ROOT(delete)); if (PARENT(tmp) == delete) { /* * Node being deleted was successor's parent. */ RIGHT(successor) = delete; PARENT(delete) = successor; } else { LEFT(PARENT(tmp)) = delete; PARENT(delete) = PARENT(tmp); } /* * Original location of successor node has no left. */ LEFT(delete) = NULL; RIGHT(delete) = RIGHT(tmp); COLOR(delete) = COLOR(tmp); } /* * Remove the node by removing the links from its parent. */ if (! IS_ROOT(delete)) { if (LEFT(PARENT(delete)) == delete) LEFT(PARENT(delete)) = child; else RIGHT(PARENT(delete)) = child; if (child != NULL) PARENT(child) = PARENT(delete); } else { /* * This is the root being deleted, and at this point * it is known to have just one child. */ *rootp = child; child->is_root = 1; PARENT(child) = PARENT(delete); } /* * Fix color violations. */ if (IS_BLACK(delete)) { parent = PARENT(delete); while (child != *rootp && IS_BLACK(child)) { INSIST(child == NULL || ! IS_ROOT(child)); if (LEFT(parent) == child) { sibling = RIGHT(parent); if (IS_RED(sibling)) { MAKE_BLACK(sibling); MAKE_RED(parent); rotate_left(parent, rootp); sibling = RIGHT(parent); } if (IS_BLACK(LEFT(sibling)) && IS_BLACK(RIGHT(sibling))) { MAKE_RED(sibling); child = parent; } else { if (IS_BLACK(RIGHT(sibling))) { MAKE_BLACK(LEFT(sibling)); MAKE_RED(sibling); rotate_right(sibling, rootp); sibling = RIGHT(parent); } COLOR(sibling) = COLOR(parent); MAKE_BLACK(parent); MAKE_BLACK(RIGHT(sibling)); rotate_left(parent, rootp); child = *rootp; } } else { /* * Child is parent's right child. * Everything is doen the same as above, * except mirrored. */ sibling = LEFT(parent); if (IS_RED(sibling)) { MAKE_BLACK(sibling); MAKE_RED(parent); rotate_right(parent, rootp); sibling = LEFT(parent); } if (IS_BLACK(LEFT(sibling)) && IS_BLACK(RIGHT(sibling))) { MAKE_RED(sibling); child = parent; } else { if (IS_BLACK(LEFT(sibling))) { MAKE_BLACK(RIGHT(sibling)); MAKE_RED(sibling); rotate_left(sibling, rootp); sibling = LEFT(parent); } COLOR(sibling) = COLOR(parent); MAKE_BLACK(parent); MAKE_BLACK(LEFT(sibling)); rotate_right(parent, rootp); child = *rootp; } } parent = PARENT(child); } if (IS_RED(child)) MAKE_BLACK(child); } } /* * This should only be used on the root of a tree, because no color fixup * is done at all. * * NOTE: No root pointer maintenance is done, because the function is only * used for two cases: * + deleting everything DOWN from a node that is itself being deleted, and * + deleting the entire tree of trees from dns_rbt_destroy. * In each case, the root pointer is no longer relevant, so there * is no need for a root parameter to this function. * * If the function is ever intended to be used to delete something where * a pointer needs to be told that this tree no longer exists, * this function would need to adjusted accordingly. */ static void dns_rbt_deletetree(dns_rbt_t *rbt, dns_rbtnode_t *node) { REQUIRE(VALID_RBT(rbt)); if (node == NULL) return; if (LEFT(node) != NULL) dns_rbt_deletetree(rbt, LEFT(node)); if (RIGHT(node) != NULL) dns_rbt_deletetree(rbt, RIGHT(node)); if (DOWN(node) != NULL) dns_rbt_deletetree(rbt, DOWN(node)); if (DATA(node) != NULL && rbt->data_deleter != NULL) rbt->data_deleter(DATA(node), rbt->deleter_arg); unhash_node(rbt, node); isc_mem_put(rbt->mctx, node, NODE_SIZE(node)); rbt->nodecount--; } static void dns_rbt_indent(int depth) { int i; for (i = 0; i < depth; i++) putchar('\t'); } static void dns_rbt_printnodename(dns_rbtnode_t *node) { isc_buffer_t target; isc_region_t r; dns_name_t name; char buffer[1024]; dns_offsets_t offsets; r.length = NAMELEN(node); r.base = NAME(node); dns_name_init(&name, offsets); dns_name_fromregion(&name, &r); isc_buffer_init(&target, buffer, 255); /* * ISC_FALSE means absolute names have the final dot added. */ dns_name_totext(&name, ISC_FALSE, &target); printf("%.*s", (int)target.used, (char *)target.base); } static void dns_rbt_printtree(dns_rbtnode_t *root, dns_rbtnode_t *parent, int depth) { dns_rbt_indent(depth); if (root != NULL) { dns_rbt_printnodename(root); printf(" (%s", IS_RED(root) ? "RED" : "black"); if (parent) { printf(" from "); dns_rbt_printnodename(parent); } if ((! IS_ROOT(root) && PARENT(root) != parent) || ( IS_ROOT(root) && depth > 0 && DOWN(PARENT(root)) != root)) { printf(" (BAD parent pointer! -> "); if (PARENT(root) != NULL) dns_rbt_printnodename(PARENT(root)); else printf("NULL"); printf(")"); } printf(")\n"); depth++; if (DOWN(root)) { dns_rbt_indent(depth); printf("++ BEG down from "); dns_rbt_printnodename(root); printf("\n"); dns_rbt_printtree(DOWN(root), NULL, depth); dns_rbt_indent(depth); printf("-- END down from "); dns_rbt_printnodename(root); printf("\n"); } if (IS_RED(root) && IS_RED(LEFT(root))) printf("** Red/Red color violation on left\n"); dns_rbt_printtree(LEFT(root), root, depth); if (IS_RED(root) && IS_RED(RIGHT(root))) printf("** Red/Red color violation on right\n"); dns_rbt_printtree(RIGHT(root), root, depth); } else printf("NULL\n"); } void dns_rbt_printall(dns_rbt_t *rbt) { REQUIRE(VALID_RBT(rbt)); dns_rbt_printtree(rbt->root, NULL, 0); } /* * Chain Functions */ void dns_rbtnodechain_init(dns_rbtnodechain_t *chain, isc_mem_t *mctx) { /* * Initialize 'chain'. */ REQUIRE(chain != NULL); chain->mctx = mctx; chain->end = NULL; chain->level_count = 0; chain->level_matches = 0; chain->magic = CHAIN_MAGIC; } isc_result_t dns_rbtnodechain_current(dns_rbtnodechain_t *chain, dns_name_t *name, dns_name_t *origin, dns_rbtnode_t **node) { isc_result_t result = ISC_R_SUCCESS; REQUIRE(VALID_CHAIN(chain)); if (node != NULL) *node = chain->end; if (chain->end == NULL) return (ISC_R_NOTFOUND); if (name != NULL) { NODENAME(chain->end, name); if (chain->level_count == 0) { /* * Names in the top level tree are all absolute. * Always make 'name' relative. */ INSIST(dns_name_isabsolute(name)); /* * This is cheaper than dns_name_getlabelsequence(). */ name->labels--; name->length--; name->attributes &= ~DNS_NAMEATTR_ABSOLUTE; } } if (origin != NULL) { if (chain->level_count > 0) result = chain_name(chain, origin, ISC_FALSE); else result = dns_name_copy(dns_rootname, origin, NULL); } return (result); } isc_result_t dns_rbtnodechain_prev(dns_rbtnodechain_t *chain, dns_name_t *name, dns_name_t *origin) { dns_rbtnode_t *current, *previous, *predecessor; isc_result_t result = ISC_R_SUCCESS; isc_boolean_t new_origin = ISC_FALSE; REQUIRE(VALID_CHAIN(chain) && chain->end != NULL); predecessor = NULL; current = chain->end; if (LEFT(current) != NULL) { /* * Moving left one then right as far as possible is the * previous node, at least for this level. */ current = LEFT(current); while (RIGHT(current) != NULL) current = RIGHT(current); predecessor = current; } else { /* * No left links, so move toward the root. If at any point on * the way there the link from parent to child is a right * link, then the parent is the previous node, at least * for this level. */ while (! IS_ROOT(current)) { previous = current; current = PARENT(current); if (RIGHT(current) == previous) { predecessor = current; break; } } } if (predecessor != NULL) { /* * Found a predecessor node in this level. It might not * really be the predecessor, however. */ if (DOWN(predecessor) != NULL) { /* * The predecessor is really down at least one level. * Go down and as far right as possible, and repeat * as long as the rightmost node has a down pointer. */ do { /* * XXX DCL Need to do something about origins * here. See whether to go down, and if so * whether it is truly what Bob calls a * new origin. */ ADD_LEVEL(chain, predecessor); predecessor = DOWN(predecessor); /* XXX DCL duplicated from above; clever * way to unduplicate? */ while (RIGHT(predecessor) != NULL) predecessor = RIGHT(predecessor); } while (DOWN(predecessor) != NULL); /* XXX DCL probably needs work on the concept */ if (origin != NULL) new_origin = ISC_TRUE; } } else if (chain->level_count > 0) { /* * Dang, didn't find a predecessor in this level. * Got to the root of this level without having traversed * any right links. Ascend the tree one level; the * node that points to this tree is the predecessor. */ INSIST(chain->level_count > 0 && IS_ROOT(current)); predecessor = chain->levels[--chain->level_count]; /* XXX DCL probably needs work on the concept */ /* * Don't declare an origin change when the new origin is "." * at the top level tree, because "." is declared as the origin * for the second level tree. */ if (origin != NULL && (chain->level_count > 0 || OFFSETLEN(predecessor) > 1)) new_origin = ISC_TRUE; } if (predecessor != NULL) { chain->end = predecessor; if (new_origin) { result = dns_rbtnodechain_current(chain, name, origin, NULL); if (result == ISC_R_SUCCESS) result = DNS_R_NEWORIGIN; } else result = dns_rbtnodechain_current(chain, name, NULL, NULL); } else result = ISC_R_NOMORE; return (result); } isc_result_t dns_rbtnodechain_next(dns_rbtnodechain_t *chain, dns_name_t *name, dns_name_t *origin) { dns_rbtnode_t *current, *previous, *successor; isc_result_t result = ISC_R_SUCCESS; isc_boolean_t new_origin = ISC_FALSE; REQUIRE(VALID_CHAIN(chain) && chain->end != NULL); successor = NULL; current = chain->end; /* * If there is a level below this node, the next node is the leftmost * node of the next level. */ if (DOWN(current) != NULL) { /* * Don't declare an origin change when the new origin is "." * at the second level tree, because "." is already declared * as the origin for the top level tree. */ if (chain->level_count > 0 || OFFSETLEN(current) > 1) new_origin = ISC_TRUE; ADD_LEVEL(chain, current); current = DOWN(current); while (LEFT(current) != NULL) current = LEFT(current); successor = current; } else if (RIGHT(current) == NULL) { /* * The successor is up, either in this level or a previous one. * Head back toward the root of the tree, looking for any path * that was via a left link; the successor is the node that has * that left link. In the event the root of the level is * reached without having traversed any left links, ascend one * level and look for either a right link off the point of * ascent, or search for a left link upward again, repeating * ascents until either case is true. */ do { while (! IS_ROOT(current)) { previous = current; current = PARENT(current); if (LEFT(current) == previous) { successor = current; break; } } if (successor == NULL) { /* * Reached the root without having traversed * any left pointers, so this level is done. */ if (chain->level_count == 0) break; current = chain->levels[--chain->level_count]; new_origin = ISC_TRUE; if (RIGHT(current) != NULL) break; } } while (successor == NULL); } if (successor == NULL && RIGHT(current) != NULL) { current = RIGHT(current); while (LEFT(current) != NULL) current = LEFT(current); successor = current; } if (successor != NULL) { chain->end = successor; /* * It is not necessary to use dns_rbtnodechain_current like * the other functions because this function will never * find a node in the topmost level. This is because the * root level will never be more than one name, and everything * in the megatree is a successor to that node, down at * the second level or below. */ if (name != NULL) NODENAME(chain->end, name); if (new_origin) { if (origin != NULL) result = chain_name(chain, origin, ISC_FALSE); if (result == ISC_R_SUCCESS) result = DNS_R_NEWORIGIN; } else result = ISC_R_SUCCESS; } else result = ISC_R_NOMORE; return (result); } isc_result_t dns_rbtnodechain_first(dns_rbtnodechain_t *chain, dns_rbt_t *rbt, dns_name_t *name, dns_name_t *origin) { isc_result_t result; REQUIRE(VALID_RBT(rbt)); REQUIRE(VALID_CHAIN(chain)); dns_rbtnodechain_reset(chain); chain->end = rbt->root; result = dns_rbtnodechain_current(chain, name, origin, NULL); if (result == ISC_R_SUCCESS) result = DNS_R_NEWORIGIN; return (result); } isc_result_t dns_rbtnodechain_last(dns_rbtnodechain_t *chain, dns_rbt_t *rbt, dns_name_t *name, dns_name_t *origin) { isc_result_t result; REQUIRE(VALID_RBT(rbt)); REQUIRE(VALID_CHAIN(chain)); dns_rbtnodechain_reset(chain); result = move_chain_to_last(chain, rbt->root); if (result != ISC_R_SUCCESS) return (result); result = dns_rbtnodechain_current(chain, name, origin, NULL); if (result == ISC_R_SUCCESS) result = DNS_R_NEWORIGIN; return (result); } void dns_rbtnodechain_reset(dns_rbtnodechain_t *chain) { /* * Free any dynamic storage associated with 'chain', and then * reinitialize 'chain'. */ REQUIRE(VALID_CHAIN(chain)); chain->end = NULL; chain->level_count = 0; chain->level_matches = 0; } void dns_rbtnodechain_invalidate(dns_rbtnodechain_t *chain) { /* * Free any dynamic storage associated with 'chain', and then * invalidate 'chain'. */ dns_rbtnodechain_reset(chain); chain->magic = 0; }