/* * Copyright (C) 2004, 2006 Internet Systems Consortium, Inc. ("ISC") * Copyright (C) 1999-2001 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 ISC DISCLAIMS ALL WARRANTIES WITH * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY * AND FITNESS. IN NO EVENT SHALL ISC 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. */ /* $Id: cache.h,v 1.17.12.5 2006/03/02 00:37:20 marka Exp $ */ #ifndef DNS_CACHE_H #define DNS_CACHE_H 1 /***** ***** Module Info *****/ /* * cache * * Defines dns_cache_t, the cache object. * * Notes: * 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: * See notes at the individual functions. * * Reliability: * * Resources: * * Security: * * Standards: */ /*** *** Imports ***/ #include <isc/lang.h> #include <isc/stdtime.h> #include <dns/types.h> ISC_LANG_BEGINDECLS /*** *** Functions ***/ isc_result_t dns_cache_create(isc_mem_t *mctx, isc_taskmgr_t *taskmgr, isc_timermgr_t *timermgr, dns_rdataclass_t rdclass, const char *db_type, unsigned int db_argc, char **db_argv, dns_cache_t **cachep); /* * Create a new DNS cache. * * Requires: * * 'mctx' is a valid memory context * * '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. * * 'cachep' is a valid pointer, and *cachep == NULL * * Ensures: * * '*cachep' is attached to the newly created cache * * Returns: * * ISC_R_SUCCESS * ISC_R_NOMEMORY */ void dns_cache_attach(dns_cache_t *cache, dns_cache_t **targetp); /* * Attach *targetp to cache. * * Requires: * * 'cache' is a valid cache. * * 'targetp' points to a NULL dns_cache_t *. * * Ensures: * * *targetp is attached to cache. */ void dns_cache_detach(dns_cache_t **cachep); /* * Detach *cachep from its cache. * * Requires: * * 'cachep' points to a valid cache. * * Ensures: * * *cachep is NULL. * * 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: * * 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: * * 'cache' is a valid cache. * * 'dbp' points to a NULL dns_db *. * * Ensures: * * *dbp is attached to the database. */ isc_result_t dns_cache_setfilename(dns_cache_t *cahce, const char *filename); /* * If 'filename' is non-NULL, make the cache persistent. * The cache's data will be stored in the given file. * If 'filename' is NULL, make the cache non-persistent. * Files that are no longer used are not unlinked automatically. * * Returns: * ISC_R_SUCCESS * ISC_R_NOMEMORY * Various file-related failures */ isc_result_t dns_cache_load(dns_cache_t *cache); /* * If the cache has a file name, load the cache contents from the file. * Previous cache contents are not discarded. * If no file name has been set, do nothing and return success. * * MT: * Multiple simultaneous attempts to load or dump the cache * will be serialized with respect to one another, but * the cache may be read and updated while the dump is * in progress. Updates performed during loading * may or may not be preserved, and reads may return * either the old or the newly loaded data. * * Returns: * * ISC_R_SUCCESS * Various failures depending on the database implementation type */ isc_result_t dns_cache_dump(dns_cache_t *cache); /* * If the cache has a file name, write the cache contents to disk, * overwriting any preexisting file. If no file name has been set, * do nothing and return success. * * MT: * Multiple simultaneous attempts to load or dump the cache * will be serialized with respect to one another, but * the cache may be read and updated while the dump is * in progress. Updates performed during the dump may * or may not be reflected in the dumped file. * * Returns: * * ISC_R_SUCCESS * Various failures depending on the database implementation type */ 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. */ void dns_cache_setcleaninginterval(dns_cache_t *cache, unsigned int interval); /* * Set the periodic cache cleaning interval to 'interval' seconds. */ void dns_cache_setcachesize(dns_cache_t *cache, isc_uint32_t size); /* * Set the maximum cache size. 0 means unlimited. */ isc_result_t dns_cache_flush(dns_cache_t *cache); /* * Flushes all data from the cache. * * Returns: * ISC_R_SUCCESS * ISC_R_NOMEMORY */ isc_result_t dns_cache_flushname(dns_cache_t *cache, dns_name_t *name); /* * Flushes a given name from the cache. * * Requires: * 'cache' to be valid. * 'name' to be valid. * * Returns: * ISC_R_SUCCESS * ISC_R_NOMEMORY * other error returns. */ ISC_LANG_ENDDECLS #endif /* DNS_CACHE_H */