/* * 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 ***/ /* Add -DDNS_CACHE_TRACE=1 to CFLAGS for detailed reference tracing */ #include #include #include #include #include #include ISC_LANG_BEGINDECLS /*** *** Functions ***/ #if DNS_CACHE_TRACE #define dns_cache_ref(ptr) dns_cache__ref(ptr, __func__, __FILE__, __LINE__) #define dns_cache_unref(ptr) dns_cache__unref(ptr, __func__, __FILE__, __LINE__) #define dns_cache_attach(ptr, ptrp) \ dns_cache__attach(ptr, ptrp, __func__, __FILE__, __LINE__) #define dns_cache_detach(ptrp) \ dns_cache__detach(ptrp, __func__, __FILE__, __LINE__) ISC_REFCOUNT_TRACE_DECL(dns_cache); #else ISC_REFCOUNT_DECL(dns_cache); #endif isc_result_t dns_cache_create(isc_loopmgr_t *loopmgr, dns_rdataclass_t rdclass, const char *cachename, isc_mem_t *mctx, dns_cache_t **cachep); /*%< * Create a new DNS cache. * * dns_cache_create() will create a named cache (based on dns_rbtdb). * * Requires: * *\li 'loopmgr' is a valid loop manager. * *\li 'cachename' is a valid string. This must not be NULL. *\li 'mctx' is a valid memory context. * *\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_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. */ 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 the data for node 'name' from the cache. * * If 'tree' is true, then also flush all nodes under 'name'. (Note that * flushing of a tree only works for names below the root. To flush the * entire tree, use dns_cache_flush().) * * Requires: *\li 'cache' to be valid. *\li 'name' to be valid. *\li if 'tree' is true, then 'name' is not root. * * 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' */ void dns_cache_setmaxrrperset(dns_cache_t *cache, uint32_t value); /*%< * Set the maximum resource records per RRSet that can be cached. */ void dns_cache_setmaxtypepername(dns_cache_t *cache, uint32_t value); /*%< * Set the maximum resource record types per owner name that can be cached. */ #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