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dns
rbt.h
/* * Copyright (C) Internet Systems Consortium, Inc. ("ISC") * * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, you can obtain one at https://mozilla.org/MPL/2.0/. * * See the COPYRIGHT file distributed with this work for additional * information regarding copyright ownership. */ #ifndef DNS_RBT_H #define DNS_RBT_H 1 /*! \file dns/rbt.h */ #include <inttypes.h> #include <stdbool.h> #include <isc/assertions.h> #include <isc/crc64.h> #include <isc/lang.h> #include <isc/magic.h> #include <isc/refcount.h> #include <dns/types.h> ISC_LANG_BEGINDECLS #define DNS_RBT_USEHASH 1 /*@{*/ /*% * Option values for dns_rbt_findnode() and dns_rbt_findname(). * These are used to form a bitmask. */ #define DNS_RBTFIND_NOOPTIONS 0x00 #define DNS_RBTFIND_EMPTYDATA 0x01 #define DNS_RBTFIND_NOEXACT 0x02 #define DNS_RBTFIND_NOPREDECESSOR 0x04 /*@}*/ #ifndef DNS_RBT_USEISCREFCOUNT #ifdef ISC_REFCOUNT_HAVEATOMIC #define DNS_RBT_USEISCREFCOUNT 1 #endif #endif #define DNS_RBT_USEMAGIC 1 /* * These should add up to 30. */ #define DNS_RBT_LOCKLENGTH 10 #define DNS_RBT_REFLENGTH 20 #define DNS_RBTNODE_MAGIC ISC_MAGIC('R','B','N','O') #if DNS_RBT_USEMAGIC #define DNS_RBTNODE_VALID(n) ISC_MAGIC_VALID(n, DNS_RBTNODE_MAGIC) #else #define DNS_RBTNODE_VALID(n) true #endif /*% * This is the structure that is used for each node in the red/black * tree of trees. NOTE WELL: the implementation manages this as a variable * length structure, with the actual wire-format name and other data * appended to this structure. Allocating a contiguous block of memory for * multiple dns_rbtnode structures will not work. */ typedef struct dns_rbtnode dns_rbtnode_t; enum { DNS_RBT_NSEC_NORMAL=0, /* in main tree */ DNS_RBT_NSEC_HAS_NSEC=1, /* also has node in nsec tree */ DNS_RBT_NSEC_NSEC=2, /* in nsec tree */ DNS_RBT_NSEC_NSEC3=3 /* in nsec3 tree */ }; struct dns_rbtnode { #if DNS_RBT_USEMAGIC unsigned int magic; #endif /*@{*/ /*! * The following bitfields add up to a total bitwidth of 32. * The range of values necessary for each item is indicated, * but in the case of "attributes" the field is wider to accommodate * possible future expansion. * * In each case below the "range" indicated is what's _necessary_ for * the bitfield to hold, not what it actually _can_ hold. * * Note: Tree lock must be held before modifying these * bit-fields. * * Note: The two "unsigned int :0;" unnamed bitfields on either * side of the bitfields below are scaffolding that border the * set of bitfields which are accessed after acquiring the tree * lock. Please don't insert any other bitfield members between * the unnamed bitfields unless they should also be accessed * after acquiring the tree lock. */ unsigned int :0; /* start of bitfields c/o tree lock */ unsigned int is_root : 1; /*%< range is 0..1 */ unsigned int color : 1; /*%< range is 0..1 */ unsigned int find_callback : 1; /*%< range is 0..1 */ unsigned int attributes : 3; /*%< range is 0..2 */ unsigned int nsec : 2; /*%< range is 0..3 */ unsigned int namelen : 8; /*%< range is 1..255 */ unsigned int offsetlen : 8; /*%< range is 1..128 */ unsigned int oldnamelen : 8; /*%< range is 1..255 */ /*@}*/ /* flags needed for serialization to file*/ unsigned int is_mmapped : 1; unsigned int parent_is_relative : 1; unsigned int left_is_relative : 1; unsigned int right_is_relative : 1; unsigned int down_is_relative : 1; unsigned int data_is_relative : 1; /* node needs to be cleaned from rpz */ unsigned int rpz : 1; unsigned int :0; /* end of bitfields c/o tree lock */ #ifdef DNS_RBT_USEHASH unsigned int hashval; dns_rbtnode_t *uppernode; dns_rbtnode_t *hashnext; #endif dns_rbtnode_t *parent; dns_rbtnode_t *left; dns_rbtnode_t *right; dns_rbtnode_t *down; /*% * Used for LRU cache. This linked list is used to mark nodes which * have no data any longer, but we cannot unlink at that exact moment * because we did not or could not obtain a write lock on the tree. */ ISC_LINK(dns_rbtnode_t) deadlink; /*@{*/ /*! * These values are used in the RBT DB implementation. The appropriate * node lock must be held before accessing them. * * Note: The two "unsigned int :0;" unnamed bitfields on either * side of the bitfields below are scaffolding that border the * set of bitfields which are accessed after acquiring the node * lock. Please don't insert any other bitfield members between * the unnamed bitfields unless they should also be accessed * after acquiring the node lock. * * NOTE: Do not merge these fields into bitfields above, as * they'll all be put in the same qword that could be accessed * without the node lock as it shares the qword with other * members. Leave these members here so that they occupy a * separate region of memory. */ void *data; unsigned int locknum; unsigned int :0; /* start of bitfields c/o node lock */ unsigned int dirty:1; unsigned int wild:1; #ifndef DNS_RBT_USEISCREFCOUNT unsigned int references:DNS_RBT_REFLENGTH; #endif unsigned int :0; /* end of bitfields c/o node lock */ #ifdef DNS_RBT_USEISCREFCOUNT isc_refcount_t references; /* note that this is not in the bitfield */ #endif /*@}*/ }; typedef isc_result_t (*dns_rbtfindcallback_t)(dns_rbtnode_t *node, dns_name_t *name, void *callback_arg); typedef isc_result_t (*dns_rbtdatawriter_t)(FILE *file, unsigned char *data, void *arg, uint64_t *crc); typedef isc_result_t (*dns_rbtdatafixer_t)(dns_rbtnode_t *rbtnode, void *base, size_t offset, void *arg, uint64_t *crc); typedef void (*dns_rbtdeleter_t)(void *, void *); /***** ***** Chain Info *****/ /*! * A chain is used to keep track of the sequence of nodes to reach any given * node from the root of the tree. Originally nodes did not have parent * pointers in them (for memory usage reasons) so there was no way to find * the path back to the root from any given node. Now that nodes have parent * pointers, chains might be going away in a future release, though the * movement functionality would remain. * * Chains may be used to iterate over a tree of trees. After setting up the * chain's structure using dns_rbtnodechain_init(), it needs to be initialized * to point to the lexically first or lexically last node in the tree of trees * using dns_rbtnodechain_first() or dns_rbtnodechain_last(), respectively. * Calling dns_rbtnodechain_next() or dns_rbtnodechain_prev() then moves the * chain over to the next or previous node, respectively. * * In any event, parent information, whether via parent pointers or chains, is * necessary information for iterating through the tree or for basic internal * tree maintenance issues (ie, the rotations that are done to rebalance the * tree when a node is added). The obvious implication of this is that for a * chain to remain valid, the tree has to be locked down against writes for the * duration of the useful life of the chain, because additions or removals can * change the path from the root to the node the chain has targeted. * * The dns_rbtnodechain_ functions _first, _last, _prev and _next all take * dns_name_t parameters for the name and the origin, which can be NULL. If * non-NULL, 'name' will end up pointing to the name data and offsets that are * stored at the node (and thus it will be read-only), so it should be a * regular dns_name_t that has been initialized with dns_name_init. When * 'origin' is non-NULL, it will get the name of the origin stored in it, so it * needs to have its own buffer space and offsets, which is most easily * accomplished with a dns_fixedname_t. It is _not_ necessary to reinitialize * either 'name' or 'origin' between calls to the chain functions. * * NOTE WELL: even though the name data at the root of the tree of trees will * be absolute (typically just "."), it will will be made into a relative name * with an origin of "." -- an empty name when the node is ".". This is * because a common on operation on 'name' and 'origin' is to use * dns_name_concatenate() on them to generate the complete name. An empty name * can be detected when dns_name_countlabels == 0, and is printed by * dns_name_totext()/dns_name_format() as "@", consistent with RFC1035's * definition of "@" as the current origin. * * dns_rbtnodechain_current is similar to the _first, _last, _prev and _next * functions but additionally can provide the node to which the chain points. */ /*% * The number of level blocks to allocate at a time. Currently the maximum * number of levels is allocated directly in the structure, but future * revisions of this code might have a static initial block with dynamic * growth. Allocating space for 256 levels when the tree is almost never that * deep is wasteful, but it's not clear that it matters, since the waste is * only 2MB for 1000 concurrently active chains on a system with 64-bit * pointers. */ #define DNS_RBT_LEVELBLOCK 254 typedef struct dns_rbtnodechain { unsigned int magic; isc_mem_t * mctx; /*% * The terminal node of the chain. It is not in levels[]. * This is ostensibly private ... but in a pinch it could be * used tell that the chain points nowhere without needing to * call dns_rbtnodechain_current(). */ dns_rbtnode_t * end; /*% * The maximum number of labels in a name is 128; bitstrings mean * a conceptually very large number (which I have not bothered to * compute) of logical levels because splitting can potentially occur * at each bit. However, DNSSEC restricts the number of "logical" * labels in a name to 255, meaning only 254 pointers are needed * in the worst case. */ dns_rbtnode_t * levels[DNS_RBT_LEVELBLOCK]; /*% * level_count indicates how deep the chain points into the * tree of trees, and is the index into the levels[] array. * Thus, levels[level_count - 1] is the last level node stored. * A chain that points to the top level of the tree of trees has * a level_count of 0, the first level has a level_count of 1, and * so on. */ unsigned int level_count; /*% * level_matches tells how many levels matched above the node * returned by dns_rbt_findnode(). A match (partial or exact) found * in the first level thus results in level_matches being set to 1. * This is used by the rbtdb to set the start point for a recursive * search of superdomains until the RR it is looking for is found. */ unsigned int level_matches; } dns_rbtnodechain_t; /***** ***** Public interfaces. *****/ isc_result_t dns_rbt_create(isc_mem_t *mctx, dns_rbtdeleter_t deleter, void *deleter_arg, dns_rbt_t **rbtp); /*%< * Initialize a red-black tree of trees. * * Notes: *\li The deleter argument, if non-null, points to a function that is * responsible for cleaning up any memory associated with the data * pointer of a node when the node is deleted. It is passed the * deleted node's data pointer as its first argument and deleter_arg * as its second argument. * * Requires: * \li mctx is a pointer to a valid memory context. *\li rbtp != NULL && *rbtp == NULL *\li arg == NULL iff deleter == NULL * * Ensures: *\li If result is ISC_R_SUCCESS: * *rbtp points to a valid red-black tree manager * *\li If result is failure: * *rbtp does not point to a valid red-black tree manager. * * Returns: *\li #ISC_R_SUCCESS Success *\li #ISC_R_NOMEMORY Resource limit: Out of Memory */ isc_result_t dns_rbt_addname(dns_rbt_t *rbt, dns_name_t *name, void *data); /*%< * Add 'name' to the tree of trees, associated with 'data'. * * Notes: *\li 'data' is never required to be non-NULL, but specifying it * when the name is added is faster than searching for 'name' * again and then setting the data pointer. The lack of a data pointer * for a node also has other ramifications regarding whether * dns_rbt_findname considers a node to exist, or dns_rbt_deletename * joins nodes. * * Requires: *\li rbt is a valid rbt manager. *\li dns_name_isabsolute(name) == TRUE * * Ensures: *\li 'name' is not altered in any way. * *\li Any external references to nodes in the tree are unaffected by * node splits that are necessary to insert the new name. * *\li If result is #ISC_R_SUCCESS: * 'name' is findable in the red/black tree of trees in O(log N). * The data pointer of the node for 'name' is set to 'data'. * *\li If result is #ISC_R_EXISTS or #ISC_R_NOSPACE: * The tree of trees is unaltered. * *\li If result is #ISC_R_NOMEMORY: * No guarantees. * * Returns: *\li #ISC_R_SUCCESS Success *\li #ISC_R_EXISTS The name already exists with associated data. *\li #ISC_R_NOSPACE The name had more logical labels than are allowed. *\li #ISC_R_NOMEMORY Resource Limit: Out of Memory */ isc_result_t dns_rbt_addnode(dns_rbt_t *rbt, dns_name_t *name, dns_rbtnode_t **nodep); /*%< * Just like dns_rbt_addname, but returns the address of the node. * * Requires: *\li rbt is a valid rbt structure. *\li dns_name_isabsolute(name) == TRUE *\li nodep != NULL && *nodep == NULL * * Ensures: *\li 'name' is not altered in any way. * *\li Any external references to nodes in the tree are unaffected by * node splits that are necessary to insert the new name. * *\li If result is ISC_R_SUCCESS: * 'name' is findable in the red/black tree of trees in O(log N). * *nodep is the node that was added for 'name'. * *\li If result is ISC_R_EXISTS: * The tree of trees is unaltered. * *nodep is the existing node for 'name'. * *\li If result is ISC_R_NOMEMORY: * No guarantees. * * Returns: *\li #ISC_R_SUCCESS Success *\li #ISC_R_EXISTS The name already exists, possibly without data. *\li #ISC_R_NOMEMORY Resource Limit: Out of Memory */ isc_result_t dns_rbt_findname(dns_rbt_t *rbt, const dns_name_t *name, unsigned int options, dns_name_t *foundname, void **data); /*%< * Get the data pointer associated with 'name'. * * Notes: *\li When #DNS_RBTFIND_NOEXACT is set, the closest matching superdomain is * returned (also subject to #DNS_RBTFIND_EMPTYDATA), even when there is * an exact match in the tree. * *\li A node that has no data is considered not to exist for this function, * unless the #DNS_RBTFIND_EMPTYDATA option is set. * * Requires: *\li rbt is a valid rbt manager. *\li dns_name_isabsolute(name) == TRUE *\li data != NULL && *data == NULL * * Ensures: *\li 'name' and the tree are not altered in any way. * *\li If result is ISC_R_SUCCESS: * *data is the data associated with 'name'. * *\li If result is DNS_R_PARTIALMATCH: * *data is the data associated with the deepest superdomain * of 'name' which has data. * *\li If result is ISC_R_NOTFOUND: * Neither the name nor a superdomain was found with data. * * Returns: *\li #ISC_R_SUCCESS Success *\li #DNS_R_PARTIALMATCH Superdomain found with data *\li #ISC_R_NOTFOUND No match *\li #ISC_R_NOSPACE Concatenating nodes to form foundname failed */ isc_result_t dns_rbt_findnode(dns_rbt_t *rbt, const 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); /*%< * Find the node for 'name'. * * Notes: *\li A node that has no data is considered not to exist for this function, * unless the DNS_RBTFIND_EMPTYDATA option is set. This applies to both * exact matches and partial matches. * *\li If the chain parameter is non-NULL, then the path through the tree * to the DNSSEC predecessor of the searched for name is maintained, * unless the DNS_RBTFIND_NOPREDECESSOR or DNS_RBTFIND_NOEXACT option * is used. (For more details on those options, see below.) * *\li If there is no predecessor, then the chain will point to nowhere, as * indicated by chain->end being NULL or dns_rbtnodechain_current * returning ISC_R_NOTFOUND. Note that in a normal Internet DNS RBT * there will always be a predecessor for all names except the root * name, because '.' will exist and '.' is the predecessor of * everything. But you can certainly construct a trivial tree and a * search for it that has no predecessor. * *\li Within the chain structure, the 'levels' member of the structure holds * the root node of each level except the first. * *\li The 'level_count' of the chain indicates how deep the chain to the * predecessor name is, as an index into the 'levels[]' array. It does * not count name elements, per se, but only levels of the tree of trees, * the distinction arising because multiple labels from a name can be * stored on only one level. It is also does not include the level * that has the node, since that level is not stored in levels[]. * *\li The chain's 'level_matches' is not directly related to the predecessor. * It is the number of levels above the level of the found 'node', * regardless of whether it was a partial match or exact match. When * the node is found in the top level tree, or no node is found at all, * level_matches is 0. * *\li When DNS_RBTFIND_NOEXACT is set, the closest matching superdomain is * returned (also subject to DNS_RBTFIND_EMPTYDATA), even when * there is an exact match in the tree. In this case, the chain * will not point to the DNSSEC predecessor, but will instead point * to the exact match, if there was any. Thus the preceding paragraphs * should have "exact match" substituted for "predecessor" to describe * how the various elements of the chain are set. This was done to * ensure that the chain's state was sane, and to prevent problems that * occurred when running the predecessor location code under conditions * it was not designed for. It is not clear *where* the chain should * point when DNS_RBTFIND_NOEXACT is set, so if you end up using a chain * with this option because you want a particular node, let us know * where you want the chain pointed, so this can be made more firm. * * Requires: *\li rbt is a valid rbt manager. *\li dns_name_isabsolute(name) == TRUE. *\li node != NULL && *node == NULL. *\li #DNS_RBTFIND_NOEXACT and DNS_RBTFIND_NOPREDECESSOR are mutually * exclusive. * * Ensures: *\li 'name' and the tree are not altered in any way. * *\li If result is ISC_R_SUCCESS: *\verbatim * *node is the terminal node for 'name'. * 'foundname' and 'name' represent the same name (though not * the same memory). * 'chain' points to the DNSSEC predecessor, if any, of 'name'. * * chain->level_matches and chain->level_count are equal. *\endverbatim * * If result is DNS_R_PARTIALMATCH: *\verbatim * *node is the data associated with the deepest superdomain * of 'name' which has data. * * 'foundname' is the name of deepest superdomain (which has * data, unless the DNS_RBTFIND_EMPTYDATA option is set). * * 'chain' points to the DNSSEC predecessor, if any, of 'name'. *\endverbatim * *\li If result is ISC_R_NOTFOUND: *\verbatim * Neither the name nor a superdomain was found. *node is NULL. * * 'chain' points to the DNSSEC predecessor, if any, of 'name'. * * chain->level_matches is 0. *\endverbatim * * Returns: *\li #ISC_R_SUCCESS Success *\li #DNS_R_PARTIALMATCH Superdomain found with data *\li #ISC_R_NOTFOUND No match, or superdomain with no data *\li #ISC_R_NOSPACE Concatenating nodes to form foundname failed */ isc_result_t dns_rbt_deletename(dns_rbt_t *rbt, dns_name_t *name, bool recurse); /*%< * Delete 'name' from the tree of trees. * * Notes: *\li When 'name' is removed, if recurse is true then all of its * subnames are removed too. * * Requires: *\li rbt is a valid rbt manager. *\li dns_name_isabsolute(name) == TRUE * * Ensures: *\li 'name' is not altered in any way. * *\li Does NOT ensure that any external references to nodes in the tree * are unaffected by node joins. * *\li If result is ISC_R_SUCCESS: * 'name' does not appear in the tree with data; however, * the node for the name might still exist which can be * found with dns_rbt_findnode (but not dns_rbt_findname). * *\li If result is ISC_R_NOTFOUND: * 'name' does not appear in the tree with data, because * it did not appear in the tree before the function was called. * *\li If result is something else: * See result codes for dns_rbt_findnode (if it fails, the * node is not deleted) or dns_rbt_deletenode (if it fails, * the node is deleted, but the tree is not optimized when * it could have been). * * Returns: *\li #ISC_R_SUCCESS Success *\li #ISC_R_NOTFOUND No match *\li something_else Any return code from dns_rbt_findnode except * DNS_R_PARTIALMATCH (which causes ISC_R_NOTFOUND * to be returned instead), and any code from * dns_rbt_deletenode. */ isc_result_t dns_rbt_deletenode(dns_rbt_t *rbt, dns_rbtnode_t *node, bool recurse); /*%< * Delete 'node' from the tree of trees. * * Notes: *\li When 'node' is removed, if recurse is true then all nodes * in levels down from it are removed too. * * Requires: *\li rbt is a valid rbt manager. *\li node != NULL. * * Ensures: *\li Does NOT ensure that any external references to nodes in the tree * are unaffected by node joins. * *\li If result is ISC_R_SUCCESS: * 'node' does not appear in the tree with data; however, * the node might still exist if it serves as a pointer to * a lower tree level as long as 'recurse' was false, hence * the node could can be found with dns_rbt_findnode when * that function's empty_data_ok parameter is true. * *\li If result is ISC_R_NOMEMORY or ISC_R_NOSPACE: * The node was deleted, but the tree structure was not * optimized. * * Returns: *\li #ISC_R_SUCCESS Success *\li #ISC_R_NOMEMORY Resource Limit: Out of Memory when joining nodes. *\li #ISC_R_NOSPACE dns_name_concatenate failed when joining nodes. */ void dns_rbt_namefromnode(dns_rbtnode_t *node, dns_name_t *name); /*%< * Convert the sequence of labels stored at 'node' into a 'name'. * * Notes: *\li This function does not return the full name, from the root, but * just the labels at the indicated node. * *\li The name data pointed to by 'name' is the information stored * in the node, not a copy. Altering the data at this pointer * will likely cause grief. * * Requires: * \li name->offsets == NULL * * Ensures: * \li 'name' is DNS_NAMEATTR_READONLY. * * \li 'name' will point directly to the labels stored after the * dns_rbtnode_t struct. * * \li 'name' will have offsets that also point to the information stored * as part of the node. */ isc_result_t dns_rbt_fullnamefromnode(dns_rbtnode_t *node, dns_name_t *name); /*%< * Like dns_rbt_namefromnode, but returns the full name from the root. * * Notes: * \li Unlike dns_rbt_namefromnode, the name will not point directly * to node data. Rather, dns_name_concatenate will be used to copy * the name data from each node into the 'name' argument. * * Requires: * \li name != NULL * \li name has a dedicated buffer. * * Returns: * \li ISC_R_SUCCESS * \li ISC_R_NOSPACE (possible via dns_name_concatenate) * \li DNS_R_NAMETOOLONG (possible via dns_name_concatenate) */ char * dns_rbt_formatnodename(dns_rbtnode_t *node, char *printname, unsigned int size); /*%< * Format the full name of a node for printing, using dns_name_format(). * * Notes: * \li 'size' is the length of the printname buffer. This should be * DNS_NAME_FORMATSIZE or larger. * * Requires: * \li node and printname are not NULL. * * Returns: * \li The 'printname' pointer. */ unsigned int dns_rbt_nodecount(dns_rbt_t *rbt); /*%< * Obtain the number of nodes in the tree of trees. * * Requires: * \li rbt is a valid rbt manager. */ size_t dns_rbt_hashsize(dns_rbt_t *rbt); /*%< * Obtain the current number of buckets in the 'rbt' hash table. * * Requires: * \li rbt is a valid rbt manager. */ void dns_rbt_destroy(dns_rbt_t **rbtp); isc_result_t dns_rbt_destroy2(dns_rbt_t **rbtp, unsigned int quantum); /*%< * Stop working with a red-black tree of trees. * If 'quantum' is zero then the entire tree will be destroyed. * If 'quantum' is non zero then up to 'quantum' nodes will be destroyed * allowing the rbt to be incrementally destroyed by repeated calls to * dns_rbt_destroy2(). Once dns_rbt_destroy2() has been called no other * operations than dns_rbt_destroy()/dns_rbt_destroy2() should be * performed on the tree of trees. * * Requires: * \li *rbt is a valid rbt manager. * * Ensures on ISC_R_SUCCESS: * \li All space allocated by the RBT library has been returned. * * \li *rbt is invalidated as an rbt manager. * * Returns: * \li ISC_R_SUCCESS * \li ISC_R_QUOTA if 'quantum' nodes have been destroyed. */ off_t dns_rbt_serialize_align(off_t target); /*%< * Align the provided integer to a pointer-size boundary. * This should be used if, during serialization of data to a will-be * mmap()ed file, a pointer alignment is needed for some data. */ isc_result_t dns_rbt_serialize_tree(FILE *file, dns_rbt_t *rbt, dns_rbtdatawriter_t datawriter, void *writer_arg, off_t *offset); /*%< * Write out the RBT structure and its data to a file. * * Notes: * \li The file must be an actual file which allows seek() calls, so it cannot * be a stream. Returns ISC_R_INVALIDFILE if not. */ isc_result_t dns_rbt_deserialize_tree(void *base_address, size_t filesize, off_t header_offset, isc_mem_t *mctx, dns_rbtdeleter_t deleter, void *deleter_arg, dns_rbtdatafixer_t datafixer, void *fixer_arg, dns_rbtnode_t **originp, dns_rbt_t **rbtp); /*%< * Read a RBT structure and its data from a file. * * If 'originp' is not NULL, then it is pointed to the root node of the RBT. * * Notes: * \li The file must be an actual file which allows seek() calls, so it cannot * be a stream. This condition is not checked in the code. */ void dns_rbt_printtext(dns_rbt_t *rbt, void (*data_printer)(FILE *, void *), FILE *f); /*%< * Print an ASCII representation of the internal structure of the red-black * tree of trees to the passed stream. * * data_printer is a callback function that is called to print the data * in a node. It should print it to the passed FILE stream. * * Notes: * \li The name stored at each node, along with the node's color, is printed. * Then the down pointer, left and right pointers are displayed * recursively in turn. NULL down pointers are silently omitted; * NULL left and right pointers are printed. */ void dns_rbt_printdot(dns_rbt_t *rbt, bool show_pointers, FILE *f); /*%< * Print a GraphViz dot representation of the internal structure of the * red-black tree of trees to the passed stream. * * If show_pointers is TRUE, pointers are also included in the generated * graph. * * Notes: * \li The name stored at each node, along with the node's color is displayed. * Then the down pointer, left and right pointers are displayed * recursively in turn. NULL left, right and down pointers are * silently omitted. */ void dns_rbt_printnodeinfo(dns_rbtnode_t *n, FILE *f); /*%< * Print out various information about a node * * Requires: *\li 'n' is a valid pointer. * *\li 'f' points to a valid open FILE structure that allows writing. */ size_t dns__rbt_getheight(dns_rbt_t *rbt); /*%< * Return the maximum height of sub-root nodes found in the red-black * forest. * * The height of a node is defined as the number of nodes in the longest * path from the node to a leaf. For each subtree in the forest, this * function determines the height of its root node. Then it returns the * maximum such height in the forest. * * Note: This function exists for testing purposes. Non-test code must * not use it. * * Requires: * \li rbt is a valid rbt manager. */ bool dns__rbt_checkproperties(dns_rbt_t *rbt); /*%< * Check red-black properties of the forest. * * Note: This function exists for testing purposes. Non-test code must * not use it. * * Requires: * \li rbt is a valid rbt manager. */ size_t dns__rbtnode_getdistance(dns_rbtnode_t *node); /*%< * Return the distance (in nodes) from the node to its upper node of its * subtree. The root node has a distance of 1. A child of the root node * has a distance of 2. */ /***** ***** Chain Functions *****/ void dns_rbtnodechain_init(dns_rbtnodechain_t *chain, isc_mem_t *mctx); /*%< * Initialize 'chain'. * * Requires: *\li 'chain' is a valid pointer. * *\li 'mctx' is a valid memory context. * * Ensures: *\li 'chain' is suitable for use. */ void dns_rbtnodechain_reset(dns_rbtnodechain_t *chain); /*%< * Free any dynamic storage associated with 'chain', and then reinitialize * 'chain'. * * Requires: *\li 'chain' is a valid pointer. * * Ensures: *\li 'chain' is suitable for use, and uses no dynamic storage. */ void dns_rbtnodechain_invalidate(dns_rbtnodechain_t *chain); /*%< * Free any dynamic storage associated with 'chain', and then invalidates it. * * Notes: *\li Future calls to any dns_rbtnodechain_ function will need to call * dns_rbtnodechain_init on the chain first (except, of course, * dns_rbtnodechain_init itself). * * Requires: *\li 'chain' is a valid chain. * * Ensures: *\li 'chain' is no longer suitable for use, and uses no dynamic storage. */ isc_result_t dns_rbtnodechain_current(dns_rbtnodechain_t *chain, dns_name_t *name, dns_name_t *origin, dns_rbtnode_t **node); /*%< * Provide the name, origin and node to which the chain is currently pointed. * * Notes: *\li The tree need not have be locked against additions for the chain * to remain valid, however there are no guarantees if any deletion * has been made since the chain was established. * * Requires: *\li 'chain' is a valid chain. * * Ensures: *\li 'node', if non-NULL, is the node to which the chain was pointed * by dns_rbt_findnode, dns_rbtnodechain_first or dns_rbtnodechain_last. * If none were called for the chain since it was initialized or reset, * or if the was no predecessor to the name searched for with * dns_rbt_findnode, then '*node' is NULL and ISC_R_NOTFOUND is returned. * *\li 'name', if non-NULL, is the name stored at the terminal level of * the chain. This is typically a single label, like the "www" of * "www.isc.org", but need not be so. At the root of the tree of trees, * if the node is "." then 'name' is ".", otherwise it is relative to ".". * (Minimalist and atypical case: if the tree has just the name * "isc.org." then the root node's stored name is "isc.org." but 'name' * will be "isc.org".) * *\li 'origin', if non-NULL, is the sequence of labels in the levels * above the terminal level, such as "isc.org." in the above example. * 'origin' is always "." for the root node. * * * Returns: *\li #ISC_R_SUCCESS name, origin & node were successfully set. *\li #ISC_R_NOTFOUND The chain does not point to any node. *\li <something_else> Any error return from dns_name_concatenate. */ isc_result_t dns_rbtnodechain_first(dns_rbtnodechain_t *chain, dns_rbt_t *rbt, dns_name_t *name, dns_name_t *origin); /*%< * Set the chain to the lexically first node in the tree of trees. * * Notes: *\li By the definition of ordering for DNS names, the root of the tree of * trees is the very first node, since everything else in the megatree * uses it as a common suffix. * * Requires: *\li 'chain' is a valid chain. *\li 'rbt' is a valid rbt manager. * * Ensures: *\li The chain points to the very first node of the tree. * *\li 'name' and 'origin', if non-NULL, are set as described for * dns_rbtnodechain_current. Thus 'origin' will always be ".". * * Returns: *\li #DNS_R_NEWORIGIN The name & origin were successfully set. *\li <something_else> Any error result from dns_rbtnodechain_current. */ isc_result_t dns_rbtnodechain_last(dns_rbtnodechain_t *chain, dns_rbt_t *rbt, dns_name_t *name, dns_name_t *origin); /*%< * Set the chain to the lexically last node in the tree of trees. * * Requires: *\li 'chain' is a valid chain. *\li 'rbt' is a valid rbt manager. * * Ensures: *\li The chain points to the very last node of the tree. * *\li 'name' and 'origin', if non-NULL, are set as described for * dns_rbtnodechain_current. * * Returns: *\li #DNS_R_NEWORIGIN The name & origin were successfully set. *\li #ISC_R_NOMEMORY Resource Limit: Out of Memory building chain. *\li <something_else> Any error result from dns_name_concatenate. */ isc_result_t dns_rbtnodechain_prev(dns_rbtnodechain_t *chain, dns_name_t *name, dns_name_t *origin); /*%< * Adjusts chain to point the DNSSEC predecessor of the name to which it * is currently pointed. * * Requires: *\li 'chain' is a valid chain. *\li 'chain' has been pointed somewhere in the tree with dns_rbt_findnode, * dns_rbtnodechain_first or dns_rbtnodechain_last -- and remember that * dns_rbt_findnode is not guaranteed to point the chain somewhere, * since there may have been no predecessor to the searched for name. * * Ensures: *\li The chain is pointed to the predecessor of its current target. * *\li 'name' and 'origin', if non-NULL, are set as described for * dns_rbtnodechain_current. * *\li 'origin' is only if a new origin was found. * * Returns: *\li #ISC_R_SUCCESS The predecessor was found and 'name' was set. *\li #DNS_R_NEWORIGIN The predecessor was found with a different * origin and 'name' and 'origin' were set. *\li #ISC_R_NOMORE There was no predecessor. *\li <something_else> Any error result from dns_rbtnodechain_current. */ isc_result_t dns_rbtnodechain_next(dns_rbtnodechain_t *chain, dns_name_t *name, dns_name_t *origin); /*%< * Adjusts chain to point the DNSSEC successor of the name to which it * is currently pointed. * * Requires: *\li 'chain' is a valid chain. *\li 'chain' has been pointed somewhere in the tree with dns_rbt_findnode, * dns_rbtnodechain_first or dns_rbtnodechain_last -- and remember that * dns_rbt_findnode is not guaranteed to point the chain somewhere, * since there may have been no predecessor to the searched for name. * * Ensures: *\li The chain is pointed to the successor of its current target. * *\li 'name' and 'origin', if non-NULL, are set as described for * dns_rbtnodechain_current. * *\li 'origin' is only if a new origin was found. * * Returns: *\li #ISC_R_SUCCESS The successor was found and 'name' was set. *\li #DNS_R_NEWORIGIN The successor was found with a different * origin and 'name' and 'origin' were set. *\li #ISC_R_NOMORE There was no successor. *\li <something_else> Any error result from dns_name_concatenate. */ isc_result_t dns_rbtnodechain_down(dns_rbtnodechain_t *chain, dns_name_t *name, dns_name_t *origin); /*%< * Descend down if possible. */ isc_result_t dns_rbtnodechain_nextflat(dns_rbtnodechain_t *chain, dns_name_t *name); /*%< * Find the next node at the current depth in DNSSEC order. */ /* * Wrapper macros for manipulating the rbtnode reference counter: * Since we selectively use isc_refcount_t for the reference counter of * a rbtnode, operations on the counter depend on the actual type of it. * The following macros provide a common interface to these operations, * hiding the back-end. The usage is the same as that of isc_refcount_xxx(). */ #ifdef DNS_RBT_USEISCREFCOUNT #define dns_rbtnode_refinit(node, n) \ do { \ isc_refcount_init(&(node)->references, (n)); \ } while (0) #define dns_rbtnode_refdestroy(node) \ do { \ isc_refcount_destroy(&(node)->references); \ } while (0) #define dns_rbtnode_refcurrent(node) \ isc_refcount_current(&(node)->references) #define dns_rbtnode_refincrement0(node, refs) \ do { \ isc_refcount_increment0(&(node)->references, (refs)); \ } while (0) #define dns_rbtnode_refincrement(node, refs) \ do { \ isc_refcount_increment(&(node)->references, (refs)); \ } while (0) #define dns_rbtnode_refdecrement(node, refs) \ do { \ isc_refcount_decrement(&(node)->references, (refs)); \ } while (0) #else /* DNS_RBT_USEISCREFCOUNT */ #define dns_rbtnode_refinit(node, n) ((node)->references = (n)) #define dns_rbtnode_refdestroy(node) ISC_REQUIRE((node)->references == 0) #define dns_rbtnode_refcurrent(node) ((node)->references) #if (__STDC_VERSION__ + 0) >= 199901L || defined __GNUC__ static inline void dns_rbtnode_refincrement0(dns_rbtnode_t *node, unsigned int *refs) { node->references++; if (refs != NULL) *refs = node->references; } static inline void dns_rbtnode_refincrement(dns_rbtnode_t *node, unsigned int *refs) { ISC_REQUIRE(node->references > 0); node->references++; if (refs != NULL) *refs = node->references; } static inline void dns_rbtnode_refdecrement(dns_rbtnode_t *node, unsigned int *refs) { ISC_REQUIRE(node->references > 0); node->references--; if (refs != NULL) *refs = node->references; } #else #define dns_rbtnode_refincrement0(node, refs) \ do { \ unsigned int *_tmp = (unsigned int *)(refs); \ (node)->references++; \ if ((_tmp) != NULL) \ (*_tmp) = (node)->references; \ } while (0) #define dns_rbtnode_refincrement(node, refs) \ do { \ ISC_REQUIRE((node)->references > 0); \ (node)->references++; \ if ((refs) != NULL) \ (*refs) = (node)->references; \ } while (0) #define dns_rbtnode_refdecrement(node, refs) \ do { \ ISC_REQUIRE((node)->references > 0); \ (node)->references--; \ if ((refs) != NULL) \ (*refs) = (node)->references; \ } while (0) #endif #endif /* DNS_RBT_USEISCREFCOUNT */ void dns_rbtnode_nodename(dns_rbtnode_t *node, dns_name_t *name); dns_rbtnode_t * dns_rbt_root(dns_rbt_t *rbt); ISC_LANG_ENDDECLS #endif /* DNS_RBT_H */
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