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Diffstat (limited to 'lib/dns/include/dns/cache.h')
| -rw-r--r-- | lib/dns/include/dns/cache.h | 302 |
1 files changed, 302 insertions, 0 deletions
diff --git a/lib/dns/include/dns/cache.h b/lib/dns/include/dns/cache.h new file mode 100644 index 0000000..8fc9657 --- /dev/null +++ b/lib/dns/include/dns/cache.h @@ -0,0 +1,302 @@ +/* + * Copyright (C) Internet Systems Consortium, Inc. ("ISC") + * + * SPDX-License-Identifier: MPL-2.0 + * + * 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. + */ + +#pragma once + +/***** +***** Module Info +*****/ + +/*! \file dns/cache.h + * \brief + * Defines dns_cache_t, the cache object. + * + * Notes: + *\li A cache object contains DNS data of a single class. + * Multiple classes will be handled by creating multiple + * views, each with a different class and its own cache. + * + * MP: + *\li See notes at the individual functions. + * + * Reliability: + * + * Resources: + * + * Security: + * + * Standards: + */ + +/*** + *** Imports + ***/ + +#include <stdbool.h> + +#include <isc/lang.h> +#include <isc/stats.h> +#include <isc/stdtime.h> + +#include <dns/types.h> + +ISC_LANG_BEGINDECLS + +/*** + *** Functions + ***/ +isc_result_t +dns_cache_create(isc_mem_t *cmctx, isc_mem_t *hmctx, isc_taskmgr_t *taskmgr, + isc_timermgr_t *timermgr, dns_rdataclass_t rdclass, + const char *cachename, const char *db_type, + unsigned int db_argc, char **db_argv, dns_cache_t **cachep); +/*%< + * Create a new DNS cache. + * + * dns_cache_create2() will create a named cache. + * + * dns_cache_create3() will create a named cache using two separate memory + * contexts, one for cache data which can be cleaned and a separate one for + * memory allocated for the heap (which can grow without an upper limit and + * has no mechanism for shrinking). + * + * dns_cache_create() is a backward compatible version that internally + * specifies an empty cache name and a single memory context. + * + * Requires: + * + *\li 'cmctx' (and 'hmctx' if applicable) is a valid memory context. + * + *\li 'taskmgr' is a valid task manager and 'timermgr' is a valid timer + * manager, or both are NULL. If NULL, no periodic cleaning of the + * cache will take place. + * + *\li 'cachename' is a valid string. This must not be NULL. + * + *\li 'cachep' is a valid pointer, and *cachep == NULL + * + * Ensures: + * + *\li '*cachep' is attached to the newly created cache + * + * Returns: + * + *\li #ISC_R_SUCCESS + *\li #ISC_R_NOMEMORY + */ + +void +dns_cache_attach(dns_cache_t *cache, dns_cache_t **targetp); +/*%< + * Attach *targetp to cache. + * + * Requires: + * + *\li 'cache' is a valid cache. + * + *\li 'targetp' points to a NULL dns_cache_t *. + * + * Ensures: + * + *\li *targetp is attached to cache. + */ + +void +dns_cache_detach(dns_cache_t **cachep); +/*%< + * Detach *cachep from its cache. + * + * Requires: + * + *\li 'cachep' points to a valid cache. + * + * Ensures: + * + *\li *cachep is NULL. + * + *\li If '*cachep' is the last reference to the cache, + * all resources used by the cache will be freed + */ + +void +dns_cache_attachdb(dns_cache_t *cache, dns_db_t **dbp); +/*%< + * Attach *dbp to the cache's database. + * + * Notes: + * + *\li This may be used to get a reference to the database for + * the purpose of cache lookups (XXX currently it is also + * the way to add data to the cache, but having a + * separate dns_cache_add() interface instead would allow + * more control over memory usage). + * The caller should call dns_db_detach() on the reference + * when it is no longer needed. + * + * Requires: + * + *\li 'cache' is a valid cache. + * + *\li 'dbp' points to a NULL dns_db *. + * + * Ensures: + * + *\li *dbp is attached to the database. + */ + +isc_result_t +dns_cache_clean(dns_cache_t *cache, isc_stdtime_t now); +/*%< + * Force immediate cleaning of the cache, freeing all rdatasets + * whose TTL has expired as of 'now' and that have no pending + * references. + */ + +const char * +dns_cache_getname(dns_cache_t *cache); +/*%< + * Get the cache name. + */ + +void +dns_cache_setcachesize(dns_cache_t *cache, size_t size); +/*%< + * Set the maximum cache size. 0 means unlimited. + */ + +size_t +dns_cache_getcachesize(dns_cache_t *cache); +/*%< + * Get the maximum cache size. + */ + +void +dns_cache_setservestalettl(dns_cache_t *cache, dns_ttl_t ttl); +/*%< + * Sets the maximum length of time that cached answers may be retained + * past their normal TTL. Default value for the library is 0, disabling + * the use of stale data. + * + * Requires: + *\li 'cache' to be valid. + */ + +dns_ttl_t +dns_cache_getservestalettl(dns_cache_t *cache); +/*%< + * Gets the maximum length of time that cached answers may be kept past + * normal expiry. + * + * Requires: + *\li 'cache' to be valid. + */ + +void +dns_cache_setservestalerefresh(dns_cache_t *cache, dns_ttl_t interval); +/*%< + * Sets the length of time to wait before attempting to refresh a rrset + * if a previous attempt in doing so has failed. + * During this time window if stale rrset are available in cache they + * will be directly returned to client. + * + * Requires: + *\li 'cache' to be valid. + */ + +dns_ttl_t +dns_cache_getservestalerefresh(dns_cache_t *cache); +/*%< + * Gets the 'stale-refresh-time' value, set by a previous call to + * 'dns_cache_setservestalerefresh'. + * + * Requires: + *\li 'cache' to be valid. + */ + +isc_result_t +dns_cache_flush(dns_cache_t *cache); +/*%< + * Flushes all data from the cache. + * + * Returns: + *\li #ISC_R_SUCCESS + *\li #ISC_R_NOMEMORY + */ + +isc_result_t +dns_cache_flushnode(dns_cache_t *cache, const dns_name_t *name, bool tree); +/* + * Flush a given name from the cache. If 'tree' is true, then + * also flush all names under 'name'. + * + * Requires: + *\li 'cache' to be valid. + *\li 'name' to be valid. + * + * Returns: + *\li #ISC_R_SUCCESS + *\li #ISC_R_NOMEMORY + *\li other error returns. + */ + +isc_result_t +dns_cache_flushname(dns_cache_t *cache, const dns_name_t *name); +/* + * Flush a given name from the cache. Equivalent to + * dns_cache_flushpartial(cache, name, false). + * + * Requires: + *\li 'cache' to be valid. + *\li 'name' to be valid. + * + * Returns: + *\li #ISC_R_SUCCESS + *\li #ISC_R_NOMEMORY + *\li other error returns. + */ + +isc_stats_t * +dns_cache_getstats(dns_cache_t *cache); +/* + * Return a pointer to the stats collection object for 'cache' + */ + +void +dns_cache_dumpstats(dns_cache_t *cache, FILE *fp); +/* + * Dump cache statistics and status in text to 'fp' + */ + +void +dns_cache_updatestats(dns_cache_t *cache, isc_result_t result); +/* + * Update cache statistics based on result code in 'result' + */ + +#ifdef HAVE_LIBXML2 +int +dns_cache_renderxml(dns_cache_t *cache, void *writer0); +/* + * Render cache statistics and status in XML for 'writer'. + */ +#endif /* HAVE_LIBXML2 */ + +#ifdef HAVE_JSON_C +isc_result_t +dns_cache_renderjson(dns_cache_t *cache, void *cstats0); +/* + * Render cache statistics and status in JSON + */ +#endif /* HAVE_JSON_C */ + +ISC_LANG_ENDDECLS |