cache.h revision ec5347e2c775f027573ce5648b910361aa926c01
297be3708069ef31814d6d75c0d71a50a78feb03Mark Andrews * Copyright (C) 2004-2006 Internet Systems Consortium, Inc. ("ISC")
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * Copyright (C) 1999-2001 Internet Software Consortium.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * Permission to use, copy, modify, and/or distribute this software for any
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * purpose with or without fee is hereby granted, provided that the above
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * copyright notice and this permission notice appear in all copies.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * PERFORMANCE OF THIS SOFTWARE.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews/* $Id: cache.h,v 1.25 2007/06/18 23:47:42 tbox Exp $ */
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews ***** Module Info
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * Defines dns_cache_t, the cache object.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li A cache object contains DNS data of a single class.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * Multiple classes will be handled by creating multiple
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * views, each with a different class and its own cache.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li See notes at the individual functions.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * Reliability:
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * Resources:
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * Standards:
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *** Functions
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrewsdns_cache_create(isc_mem_t *mctx, isc_taskmgr_t *taskmgr,
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews isc_timermgr_t *timermgr, dns_rdataclass_t rdclass,
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews const char *db_type, unsigned int db_argc, char **db_argv,
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * Create a new DNS cache.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li 'mctx' is a valid memory context
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li 'taskmgr' is a valid task manager and 'timermgr' is a valid timer
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * manager, or both are NULL. If NULL, no periodic cleaning of the
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * cache will take place.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li 'cachep' is a valid pointer, and *cachep == NULL
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li '*cachep' is attached to the newly created cache
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li #ISC_R_SUCCESS
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li #ISC_R_NOMEMORY
b3cbb2f1ad021349e89807f3492df6e4e679cd56Mark Andrewsdns_cache_attach(dns_cache_t *cache, dns_cache_t **targetp);
b3cbb2f1ad021349e89807f3492df6e4e679cd56Mark Andrews * Attach *targetp to cache.
b3cbb2f1ad021349e89807f3492df6e4e679cd56Mark Andrews *\li 'cache' is a valid cache.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li 'targetp' points to a NULL dns_cache_t *.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li *targetp is attached to cache.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * Detach *cachep from its cache.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li 'cachep' points to a valid cache.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li *cachep is NULL.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li If '*cachep' is the last reference to the cache,
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * all resources used by the cache will be freed
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrewsdns_cache_attachdb(dns_cache_t *cache, dns_db_t **dbp);
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * Attach *dbp to the cache's database.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li This may be used to get a reference to the database for
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * the purpose of cache lookups (XXX currently it is also
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * the way to add data to the cache, but having a
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * separate dns_cache_add() interface instead would allow
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * more control over memory usage).
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * The caller should call dns_db_detach() on the reference
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * when it is no longer needed.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li 'cache' is a valid cache.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li 'dbp' points to a NULL dns_db *.
8dc5d5e460da15b2481893687cad7e5b72d0314aAutomatic Updater *\li *dbp is attached to the database.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrewsdns_cache_setfilename(dns_cache_t *cache, const char *filename);
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * If 'filename' is non-NULL, make the cache persistent.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * The cache's data will be stored in the given file.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * If 'filename' is NULL, make the cache non-persistent.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * Files that are no longer used are not unlinked automatically.
a1b05dea35aa30b152a47115e18bbe679d3fcf19Mark Andrews *\li #ISC_R_SUCCESS
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li #ISC_R_NOMEMORY
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li Various file-related failures
d71e2e0c61df16ff37c9934c371a4a60c08974f7Mark Andrews * If the cache has a file name, load the cache contents from the file.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * Previous cache contents are not discarded.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * If no file name has been set, do nothing and return success.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li Multiple simultaneous attempts to load or dump the cache
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * will be serialized with respect to one another, but
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * the cache may be read and updated while the dump is
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * in progress. Updates performed during loading
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * may or may not be preserved, and reads may return
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * either the old or the newly loaded data.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li #ISC_R_SUCCESS
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * \li Various failures depending on the database implementation type
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * If the cache has a file name, write the cache contents to disk,
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * overwriting any preexisting file. If no file name has been set,
f6da30bb5447c23d880b09f601441e70c5313557Mark Andrews * do nothing and return success.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li Multiple simultaneous attempts to load or dump the cache
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * will be serialized with respect to one another, but
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * the cache may be read and updated while the dump is
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * in progress. Updates performed during the dump may
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * or may not be reflected in the dumped file.
d71e2e0c61df16ff37c9934c371a4a60c08974f7Mark Andrews *\li #ISC_R_SUCCESS
8c9957e63274e6ea44d182703116307b1a65dabbMark Andrews * \li Various failures depending on the database implementation type
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrewsdns_cache_clean(dns_cache_t *cache, isc_stdtime_t now);
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * Force immediate cleaning of the cache, freeing all rdatasets
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * whose TTL has expired as of 'now' and that have no pending
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * references.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrewsdns_cache_setcleaninginterval(dns_cache_t *cache, unsigned int interval);
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * Set the periodic cache cleaning interval to 'interval' seconds.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrewsdns_cache_setcachesize(dns_cache_t *cache, isc_uint32_t size);
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * Set the maximum cache size. 0 means unlimited.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * Flushes all data from the cache.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li #ISC_R_SUCCESS
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li #ISC_R_NOMEMORY
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrewsdns_cache_flushname(dns_cache_t *cache, dns_name_t *name);
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews * Flushes a given name from the cache.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li 'cache' to be valid.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li 'name' to be valid.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li #ISC_R_SUCCESS
8dc5d5e460da15b2481893687cad7e5b72d0314aAutomatic Updater *\li #ISC_R_NOMEMORY
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews *\li other error returns.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews#endif /* DNS_CACHE_H */