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Diffstat (limited to 'lib/dns/include/dns/cache.h')
| -rw-r--r-- | lib/dns/include/dns/cache.h | 253 |
1 files changed, 253 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..7b37235 --- /dev/null +++ b/lib/dns/include/dns/cache.h @@ -0,0 +1,253 @@ +/* + * Copyright (C) 2004-2007 Internet Systems Consortium, Inc. ("ISC") + * Copyright (C) 1999-2001 Internet Software Consortium. + * + * Permission to use, copy, modify, and/or 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 1.26 2007/06/19 23:47:16 tbox Exp $ */ + +#ifndef DNS_CACHE_H +#define DNS_CACHE_H 1 + +/***** + ***** 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 <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: + * + *\li 'mctx' 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 '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_setfilename(dns_cache_t *cache, 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: + *\li #ISC_R_SUCCESS + *\li #ISC_R_NOMEMORY + *\li 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: + *\li 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: + * + *\li #ISC_R_SUCCESS + * \li 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: + *\li 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: + * + *\li #ISC_R_SUCCESS + * \li 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: + *\li #ISC_R_SUCCESS + *\li #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: + *\li 'cache' to be valid. + *\li 'name' to be valid. + * + * Returns: + *\li #ISC_R_SUCCESS + *\li #ISC_R_NOMEMORY + *\li other error returns. + */ + +ISC_LANG_ENDDECLS + +#endif /* DNS_CACHE_H */ |