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/*
* 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 */