/* * Copyright (C) 2004-2006 Internet Systems Consortium, Inc. ("ISC") * Copyright (C) 1999-2003 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. */ /* $ISC: cache.c,v 1.57.18.16 2006/08/01 01:06:48 marka Exp $ */ /*! \file */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define CACHE_MAGIC ISC_MAGIC('$', '$', '$', '$') #define VALID_CACHE(cache) ISC_MAGIC_VALID(cache, CACHE_MAGIC) /*! * Control incremental cleaning. * DNS_CACHE_MINSIZE is how many bytes is the floor for dns_cache_setcachesize(). * See also DNS_CACHE_CLEANERINCREMENT */ #define DNS_CACHE_MINSIZE 2097152 /*%< Bytes. 2097152 = 2 MB */ /*! * Control incremental cleaning. * CLEANERINCREMENT is how many nodes are examined in one pass. * See also DNS_CACHE_MINSIZE */ #define DNS_CACHE_CLEANERINCREMENT 1000U /*%< Number of nodes. */ /*** *** Types ***/ /* * A cache_cleaner_t encapsulsates the state of the periodic * cache cleaning. */ typedef struct cache_cleaner cache_cleaner_t; typedef enum { cleaner_s_idle, /*%< Waiting for cleaning-interval to expire. */ cleaner_s_busy, /*%< Currently cleaning. */ cleaner_s_done /*%< Freed enough memory after being overmem. */ } cleaner_state_t; /* * Convenience macros for comprehensive assertion checking. */ #define CLEANER_IDLE(c) ((c)->state == cleaner_s_idle && \ (c)->resched_event != NULL) #define CLEANER_BUSY(c) ((c)->state == cleaner_s_busy && \ (c)->iterator != NULL && \ (c)->resched_event == NULL) /*% * Accesses to a cache cleaner object are synchronized through * task/event serialization, or locked from the cache object. */ struct cache_cleaner { isc_mutex_t lock; /*%< * Locks overmem_event, overmem. Note: never allocate memory * while holding this lock - that could lead to deadlock since * the lock is take by water() which is called from the memory * allocator. */ dns_cache_t *cache; isc_task_t *task; unsigned int cleaning_interval; /*% The cleaning-interval from named.conf, in seconds. */ isc_timer_t *cleaning_timer; isc_event_t *resched_event; /*% Sent by cleaner task to itself to reschedule */ isc_event_t *overmem_event; dns_dbiterator_t *iterator; unsigned int increment; /*% Number of names to clean in one increment */ cleaner_state_t state; /*% Idle/Busy. */ isc_boolean_t overmem; /*% The cache is in an overmem state. */ isc_boolean_t replaceiterator; }; /*% * The actual cache object. */ struct dns_cache { /* Unlocked. */ unsigned int magic; isc_mutex_t lock; isc_mutex_t filelock; isc_mem_t *mctx; /* Locked by 'lock'. */ int references; int live_tasks; dns_rdataclass_t rdclass; dns_db_t *db; cache_cleaner_t cleaner; char *db_type; int db_argc; char **db_argv; /* Locked by 'filelock'. */ char * filename; /* Access to the on-disk cache file is also locked by 'filelock'. */ }; /*** *** Functions ***/ static isc_result_t cache_cleaner_init(dns_cache_t *cache, isc_taskmgr_t *taskmgr, isc_timermgr_t *timermgr, cache_cleaner_t *cleaner); static void cleaning_timer_action(isc_task_t *task, isc_event_t *event); static void incremental_cleaning_action(isc_task_t *task, isc_event_t *event); static void cleaner_shutdown_action(isc_task_t *task, isc_event_t *event); static void overmem_cleaning_action(isc_task_t *task, isc_event_t *event); /*% * Work out how many nodes can be cleaned in the time between two * requests to the nameserver. Smooth the resulting number and use * it as a estimate for the number of nodes to be cleaned in the next * iteration. */ static void adjust_increment(cache_cleaner_t *cleaner, unsigned int remaining, isc_time_t *start) { isc_time_t end; isc_uint64_t usecs; isc_uint64_t new; unsigned int pps = dns_pps; unsigned int interval; unsigned int names; /* * Tune for minumum of 100 packets per second (pps). */ if (pps < 100) pps = 100; isc_time_now(&end); interval = 1000000 / pps; /* Interval between packets in usecs. */ if (interval == 0) interval = 1; INSIST(cleaner->increment >= remaining); names = cleaner->increment - remaining; usecs = isc_time_microdiff(&end, start); isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_CACHE, ISC_LOG_DEBUG(1), "adjust_increment interval=%u " "names=%u usec=%" ISC_PLATFORM_QUADFORMAT "u", interval, names, usecs); if (usecs == 0) { /* * If we cleaned all the nodes in unmeasurable time * double the number of nodes to be cleaned next time. */ if (names == cleaner->increment) { cleaner->increment *= 2; if (cleaner->increment > DNS_CACHE_CLEANERINCREMENT) cleaner->increment = DNS_CACHE_CLEANERINCREMENT; isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_CACHE, ISC_LOG_DEBUG(1), "%p:new cleaner->increment = %u\n", cleaner, cleaner->increment); } return; } new = (names * interval); new /= (usecs * 2); if (new == 0) new = 1; /* Smooth */ new = (new + cleaner->increment * 7) / 8; if (new > DNS_CACHE_CLEANERINCREMENT) new = DNS_CACHE_CLEANERINCREMENT; cleaner->increment = (unsigned int)new; isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_CACHE, ISC_LOG_DEBUG(1), "%p:new cleaner->increment = %u\n", cleaner, cleaner->increment); } static inline isc_result_t cache_create_db(dns_cache_t *cache, dns_db_t **db) { return (dns_db_create(cache->mctx, cache->db_type, dns_rootname, dns_dbtype_cache, cache->rdclass, cache->db_argc, cache->db_argv, db)); } 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) { isc_result_t result; dns_cache_t *cache; int i; REQUIRE(cachep != NULL); REQUIRE(*cachep == NULL); REQUIRE(mctx != NULL); cache = isc_mem_get(mctx, sizeof(*cache)); if (cache == NULL) return (ISC_R_NOMEMORY); cache->mctx = NULL; isc_mem_attach(mctx, &cache->mctx); result = isc_mutex_init(&cache->lock); if (result != ISC_R_SUCCESS) goto cleanup_mem; result = isc_mutex_init(&cache->filelock); if (result != ISC_R_SUCCESS) goto cleanup_lock; cache->references = 1; cache->live_tasks = 0; cache->rdclass = rdclass; cache->db_type = isc_mem_strdup(mctx, db_type); if (cache->db_type == NULL) { result = ISC_R_NOMEMORY; goto cleanup_filelock; } cache->db_argc = db_argc; if (cache->db_argc == 0) cache->db_argv = NULL; else { cache->db_argv = isc_mem_get(mctx, cache->db_argc * sizeof(char *)); if (cache->db_argv == NULL) { result = ISC_R_NOMEMORY; goto cleanup_dbtype; } for (i = 0; i < cache->db_argc; i++) cache->db_argv[i] = NULL; for (i = 0; i < cache->db_argc; i++) { cache->db_argv[i] = isc_mem_strdup(mctx, db_argv[i]); if (cache->db_argv[i] == NULL) { result = ISC_R_NOMEMORY; goto cleanup_dbargv; } } } cache->db = NULL; result = cache_create_db(cache, &cache->db); if (result != ISC_R_SUCCESS) goto cleanup_dbargv; cache->filename = NULL; cache->magic = CACHE_MAGIC; result = cache_cleaner_init(cache, taskmgr, timermgr, &cache->cleaner); if (result != ISC_R_SUCCESS) goto cleanup_db; *cachep = cache; return (ISC_R_SUCCESS); cleanup_db: dns_db_detach(&cache->db); cleanup_dbargv: for (i = 0; i < cache->db_argc; i++) if (cache->db_argv[i] != NULL) isc_mem_free(mctx, cache->db_argv[i]); if (cache->db_argv != NULL) isc_mem_put(mctx, cache->db_argv, cache->db_argc * sizeof(char *)); cleanup_dbtype: isc_mem_free(mctx, cache->db_type); cleanup_filelock: DESTROYLOCK(&cache->filelock); cleanup_lock: DESTROYLOCK(&cache->lock); cleanup_mem: isc_mem_put(mctx, cache, sizeof(*cache)); isc_mem_detach(&mctx); return (result); } static void cache_free(dns_cache_t *cache) { isc_mem_t *mctx; int i; REQUIRE(VALID_CACHE(cache)); REQUIRE(cache->references == 0); isc_mem_setwater(cache->mctx, NULL, NULL, 0, 0); if (cache->cleaner.task != NULL) isc_task_detach(&cache->cleaner.task); if (cache->cleaner.overmem_event != NULL) isc_event_free(&cache->cleaner.overmem_event); if (cache->cleaner.resched_event != NULL) isc_event_free(&cache->cleaner.resched_event); if (cache->cleaner.iterator != NULL) dns_dbiterator_destroy(&cache->cleaner.iterator); DESTROYLOCK(&cache->cleaner.lock); if (cache->filename) { isc_mem_free(cache->mctx, cache->filename); cache->filename = NULL; } if (cache->db != NULL) dns_db_detach(&cache->db); if (cache->db_argv != NULL) { for (i = 0; i < cache->db_argc; i++) if (cache->db_argv[i] != NULL) isc_mem_free(cache->mctx, cache->db_argv[i]); isc_mem_put(cache->mctx, cache->db_argv, cache->db_argc * sizeof(char *)); } if (cache->db_type != NULL) isc_mem_free(cache->mctx, cache->db_type); DESTROYLOCK(&cache->lock); DESTROYLOCK(&cache->filelock); cache->magic = 0; mctx = cache->mctx; isc_mem_put(cache->mctx, cache, sizeof(*cache)); isc_mem_detach(&mctx); } void dns_cache_attach(dns_cache_t *cache, dns_cache_t **targetp) { REQUIRE(VALID_CACHE(cache)); REQUIRE(targetp != NULL && *targetp == NULL); LOCK(&cache->lock); cache->references++; UNLOCK(&cache->lock); *targetp = cache; } void dns_cache_detach(dns_cache_t **cachep) { dns_cache_t *cache; isc_boolean_t free_cache = ISC_FALSE; REQUIRE(cachep != NULL); cache = *cachep; REQUIRE(VALID_CACHE(cache)); LOCK(&cache->lock); REQUIRE(cache->references > 0); cache->references--; if (cache->references == 0) { cache->cleaner.overmem = ISC_FALSE; free_cache = ISC_TRUE; } *cachep = NULL; if (free_cache) { /* * When the cache is shut down, dump it to a file if one is * specified. */ isc_result_t result = dns_cache_dump(cache); if (result != ISC_R_SUCCESS) isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_CACHE, ISC_LOG_WARNING, "error dumping cache: %s ", isc_result_totext(result)); /* * If the cleaner task exists, let it free the cache. */ if (cache->live_tasks > 0) { isc_task_shutdown(cache->cleaner.task); free_cache = ISC_FALSE; } } UNLOCK(&cache->lock); if (free_cache) cache_free(cache); } void dns_cache_attachdb(dns_cache_t *cache, dns_db_t **dbp) { REQUIRE(VALID_CACHE(cache)); REQUIRE(dbp != NULL && *dbp == NULL); REQUIRE(cache->db != NULL); LOCK(&cache->lock); dns_db_attach(cache->db, dbp); UNLOCK(&cache->lock); } isc_result_t dns_cache_setfilename(dns_cache_t *cache, const char *filename) { char *newname; REQUIRE(VALID_CACHE(cache)); REQUIRE(filename != NULL); newname = isc_mem_strdup(cache->mctx, filename); if (newname == NULL) return (ISC_R_NOMEMORY); LOCK(&cache->filelock); if (cache->filename) isc_mem_free(cache->mctx, cache->filename); cache->filename = newname; UNLOCK(&cache->filelock); return (ISC_R_SUCCESS); } isc_result_t dns_cache_load(dns_cache_t *cache) { isc_result_t result; REQUIRE(VALID_CACHE(cache)); if (cache->filename == NULL) return (ISC_R_SUCCESS); LOCK(&cache->filelock); result = dns_db_load(cache->db, cache->filename); UNLOCK(&cache->filelock); return (result); } isc_result_t dns_cache_dump(dns_cache_t *cache) { isc_result_t result; REQUIRE(VALID_CACHE(cache)); if (cache->filename == NULL) return (ISC_R_SUCCESS); LOCK(&cache->filelock); result = dns_master_dump(cache->mctx, cache->db, NULL, &dns_master_style_cache, cache->filename); UNLOCK(&cache->filelock); return (result); } void dns_cache_setcleaninginterval(dns_cache_t *cache, unsigned int t) { isc_interval_t interval; isc_result_t result; LOCK(&cache->lock); /* * It may be the case that the cache has already shut down. * If so, it has no timer. */ if (cache->cleaner.cleaning_timer == NULL) goto unlock; cache->cleaner.cleaning_interval = t; if (t == 0) { result = isc_timer_reset(cache->cleaner.cleaning_timer, isc_timertype_inactive, NULL, NULL, ISC_TRUE); } else { isc_interval_set(&interval, cache->cleaner.cleaning_interval, 0); result = isc_timer_reset(cache->cleaner.cleaning_timer, isc_timertype_ticker, NULL, &interval, ISC_FALSE); } if (result != ISC_R_SUCCESS) isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_CACHE, ISC_LOG_WARNING, "could not set cache cleaning interval: %s", isc_result_totext(result)); unlock: UNLOCK(&cache->lock); } /* * Initialize the cache cleaner object at *cleaner. * Space for the object must be allocated by the caller. */ static isc_result_t cache_cleaner_init(dns_cache_t *cache, isc_taskmgr_t *taskmgr, isc_timermgr_t *timermgr, cache_cleaner_t *cleaner) { isc_result_t result; result = isc_mutex_init(&cleaner->lock); if (result != ISC_R_SUCCESS) goto fail; cleaner->increment = DNS_CACHE_CLEANERINCREMENT; cleaner->state = cleaner_s_idle; cleaner->cache = cache; cleaner->iterator = NULL; cleaner->overmem = ISC_FALSE; cleaner->replaceiterator = ISC_FALSE; cleaner->task = NULL; cleaner->cleaning_timer = NULL; cleaner->resched_event = NULL; cleaner->overmem_event = NULL; result = dns_db_createiterator(cleaner->cache->db, ISC_FALSE, &cleaner->iterator); if (result != ISC_R_SUCCESS) goto cleanup; if (taskmgr != NULL && timermgr != NULL) { result = isc_task_create(taskmgr, 1, &cleaner->task); if (result != ISC_R_SUCCESS) { UNEXPECTED_ERROR(__FILE__, __LINE__, "isc_task_create() failed: %s", dns_result_totext(result)); result = ISC_R_UNEXPECTED; goto cleanup; } cleaner->cache->live_tasks++; isc_task_setname(cleaner->task, "cachecleaner", cleaner); result = isc_task_onshutdown(cleaner->task, cleaner_shutdown_action, cache); if (result != ISC_R_SUCCESS) { UNEXPECTED_ERROR(__FILE__, __LINE__, "cache cleaner: " "isc_task_onshutdown() failed: %s", dns_result_totext(result)); goto cleanup; } cleaner->cleaning_interval = 0; /* Initially turned off. */ result = isc_timer_create(timermgr, isc_timertype_inactive, NULL, NULL, cleaner->task, cleaning_timer_action, cleaner, &cleaner->cleaning_timer); if (result != ISC_R_SUCCESS) { UNEXPECTED_ERROR(__FILE__, __LINE__, "isc_timer_create() failed: %s", dns_result_totext(result)); result = ISC_R_UNEXPECTED; goto cleanup; } cleaner->resched_event = isc_event_allocate(cache->mctx, cleaner, DNS_EVENT_CACHECLEAN, incremental_cleaning_action, cleaner, sizeof(isc_event_t)); if (cleaner->resched_event == NULL) { result = ISC_R_NOMEMORY; goto cleanup; } cleaner->overmem_event = isc_event_allocate(cache->mctx, cleaner, DNS_EVENT_CACHEOVERMEM, overmem_cleaning_action, cleaner, sizeof(isc_event_t)); if (cleaner->overmem_event == NULL) { result = ISC_R_NOMEMORY; goto cleanup; } } return (ISC_R_SUCCESS); cleanup: if (cleaner->overmem_event != NULL) isc_event_free(&cleaner->overmem_event); if (cleaner->resched_event != NULL) isc_event_free(&cleaner->resched_event); if (cleaner->cleaning_timer != NULL) isc_timer_detach(&cleaner->cleaning_timer); if (cleaner->task != NULL) isc_task_detach(&cleaner->task); if (cleaner->iterator != NULL) dns_dbiterator_destroy(&cleaner->iterator); DESTROYLOCK(&cleaner->lock); fail: return (result); } static void begin_cleaning(cache_cleaner_t *cleaner) { isc_result_t result = ISC_R_SUCCESS; REQUIRE(CLEANER_IDLE(cleaner)); /* * Create an iterator, if it does not already exist, and * position it at the beginning of the cache. */ if (cleaner->iterator == NULL) result = dns_db_createiterator(cleaner->cache->db, ISC_FALSE, &cleaner->iterator); if (result != ISC_R_SUCCESS) isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_CACHE, ISC_LOG_WARNING, "cache cleaner could not create " "iterator: %s", isc_result_totext(result)); else { dns_dbiterator_setcleanmode(cleaner->iterator, ISC_TRUE); result = dns_dbiterator_first(cleaner->iterator); } if (result != ISC_R_SUCCESS) { /* * If the result is ISC_R_NOMORE, the database is empty, * so there is nothing to be cleaned. */ if (result != ISC_R_NOMORE && cleaner->iterator != NULL) { UNEXPECTED_ERROR(__FILE__, __LINE__, "cache cleaner: " "dns_dbiterator_first() failed: %s", dns_result_totext(result)); dns_dbiterator_destroy(&cleaner->iterator); } else if (cleaner->iterator != NULL) { result = dns_dbiterator_pause(cleaner->iterator); RUNTIME_CHECK(result == ISC_R_SUCCESS); } } else { /* * Pause the iterator to free its lock. */ result = dns_dbiterator_pause(cleaner->iterator); RUNTIME_CHECK(result == ISC_R_SUCCESS); isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_CACHE, ISC_LOG_DEBUG(1), "begin cache cleaning, mem inuse %lu", (unsigned long)isc_mem_inuse(cleaner->cache->mctx)); cleaner->state = cleaner_s_busy; isc_task_send(cleaner->task, &cleaner->resched_event); } return; } static void end_cleaning(cache_cleaner_t *cleaner, isc_event_t *event) { isc_result_t result; REQUIRE(CLEANER_BUSY(cleaner)); REQUIRE(event != NULL); result = dns_dbiterator_pause(cleaner->iterator); if (result != ISC_R_SUCCESS) dns_dbiterator_destroy(&cleaner->iterator); dns_cache_setcleaninginterval(cleaner->cache, cleaner->cleaning_interval); isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_CACHE, ISC_LOG_DEBUG(1), "end cache cleaning, mem inuse %lu", (unsigned long)isc_mem_inuse(cleaner->cache->mctx)); cleaner->state = cleaner_s_idle; cleaner->resched_event = event; } /* * This is run once for every cache-cleaning-interval as defined in named.conf. */ static void cleaning_timer_action(isc_task_t *task, isc_event_t *event) { cache_cleaner_t *cleaner = event->ev_arg; UNUSED(task); INSIST(task == cleaner->task); INSIST(event->ev_type == ISC_TIMEREVENT_TICK); isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_CACHE, ISC_LOG_DEBUG(1), "cache cleaning timer fired, " "cleaner state = %d", cleaner->state); if (cleaner->state == cleaner_s_idle) begin_cleaning(cleaner); isc_event_free(&event); } /* * This is called when the cache either surpasses its upper limit * or shrinks beyond its lower limit. */ static void overmem_cleaning_action(isc_task_t *task, isc_event_t *event) { cache_cleaner_t *cleaner = event->ev_arg; isc_boolean_t want_cleaning = ISC_FALSE; UNUSED(task); INSIST(task == cleaner->task); INSIST(event->ev_type == DNS_EVENT_CACHEOVERMEM); INSIST(cleaner->overmem_event == NULL); isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_CACHE, ISC_LOG_DEBUG(1), "overmem_cleaning_action called, " "overmem = %d, state = %d", cleaner->overmem, cleaner->state); LOCK(&cleaner->lock); if (cleaner->overmem) { if (cleaner->state == cleaner_s_idle) want_cleaning = ISC_TRUE; } else { if (cleaner->state == cleaner_s_busy) /* * end_cleaning() can't be called here because * then both cleaner->overmem_event and * cleaner->resched_event will point to this * event. Set the state to done, and then * when the incremental_cleaning_action() event * is posted, it will handle the end_cleaning. */ cleaner->state = cleaner_s_done; } cleaner->overmem_event = event; UNLOCK(&cleaner->lock); if (want_cleaning) begin_cleaning(cleaner); } /* * Do incremental cleaning. */ static void incremental_cleaning_action(isc_task_t *task, isc_event_t *event) { cache_cleaner_t *cleaner = event->ev_arg; isc_result_t result; unsigned int n_names; isc_time_t start; UNUSED(task); INSIST(task == cleaner->task); INSIST(event->ev_type == DNS_EVENT_CACHECLEAN); if (cleaner->state == cleaner_s_done) { cleaner->state = cleaner_s_busy; end_cleaning(cleaner, event); LOCK(&cleaner->cache->lock); LOCK(&cleaner->lock); if (cleaner->replaceiterator) { dns_dbiterator_destroy(&cleaner->iterator); (void) dns_db_createiterator(cleaner->cache->db, ISC_FALSE, &cleaner->iterator); cleaner->replaceiterator = ISC_FALSE; } UNLOCK(&cleaner->lock); UNLOCK(&cleaner->cache->lock); return; } INSIST(CLEANER_BUSY(cleaner)); n_names = cleaner->increment; REQUIRE(DNS_DBITERATOR_VALID(cleaner->iterator)); isc_time_now(&start); while (n_names-- > 0) { dns_dbnode_t *node = NULL; result = dns_dbiterator_current(cleaner->iterator, &node, NULL); if (result != ISC_R_SUCCESS) { UNEXPECTED_ERROR(__FILE__, __LINE__, "cache cleaner: dns_dbiterator_current() " "failed: %s", dns_result_totext(result)); adjust_increment(cleaner, n_names, &start); end_cleaning(cleaner, event); return; } /* * The node was not needed, but was required by * dns_dbiterator_current(). Give up its reference. */ dns_db_detachnode(cleaner->cache->db, &node); /* * Step to the next node. */ result = dns_dbiterator_next(cleaner->iterator); if (result != ISC_R_SUCCESS) { /* * Either the end was reached (ISC_R_NOMORE) or * some error was signaled. If the cache is still * overmem and no error was encountered, * keep trying to clean it, otherwise stop cleaning. */ if (result != ISC_R_NOMORE) UNEXPECTED_ERROR(__FILE__, __LINE__, "cache cleaner: " "dns_dbiterator_next() " "failed: %s", dns_result_totext(result)); else if (cleaner->overmem) { result = dns_dbiterator_first(cleaner-> iterator); if (result == ISC_R_SUCCESS) { isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_CACHE, ISC_LOG_DEBUG(1), "cache cleaner: " "still overmem, " "reset and try again"); continue; } } adjust_increment(cleaner, n_names, &start); end_cleaning(cleaner, event); return; } } adjust_increment(cleaner, 0U, &start); /* * We have successfully performed a cleaning increment but have * not gone through the entire cache. Free the iterator locks * and reschedule another batch. If it fails, just try to continue * anyway. */ result = dns_dbiterator_pause(cleaner->iterator); RUNTIME_CHECK(result == ISC_R_SUCCESS); isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_CACHE, ISC_LOG_DEBUG(1), "cache cleaner: checked %u nodes, " "mem inuse %lu, sleeping", cleaner->increment, (unsigned long)isc_mem_inuse(cleaner->cache->mctx)); isc_task_send(task, &event); INSIST(CLEANER_BUSY(cleaner)); return; } /* * Do immediate cleaning. */ isc_result_t dns_cache_clean(dns_cache_t *cache, isc_stdtime_t now) { isc_result_t result; dns_dbiterator_t *iterator = NULL; REQUIRE(VALID_CACHE(cache)); result = dns_db_createiterator(cache->db, ISC_FALSE, &iterator); if (result != ISC_R_SUCCESS) return result; result = dns_dbiterator_first(iterator); while (result == ISC_R_SUCCESS) { dns_dbnode_t *node = NULL; result = dns_dbiterator_current(iterator, &node, (dns_name_t *)NULL); if (result != ISC_R_SUCCESS) break; /* * Check TTLs, mark expired rdatasets stale. */ result = dns_db_expirenode(cache->db, node, now); if (result != ISC_R_SUCCESS) { UNEXPECTED_ERROR(__FILE__, __LINE__, "cache cleaner: dns_db_expirenode() " "failed: %s", dns_result_totext(result)); /* * Continue anyway. */ } /* * This is where the actual freeing takes place. */ dns_db_detachnode(cache->db, &node); result = dns_dbiterator_next(iterator); } dns_dbiterator_destroy(&iterator); if (result == ISC_R_NOMORE) result = ISC_R_SUCCESS; return (result); } static void water(void *arg, int mark) { dns_cache_t *cache = arg; isc_boolean_t overmem = ISC_TF(mark == ISC_MEM_HIWATER); REQUIRE(VALID_CACHE(cache)); LOCK(&cache->cleaner.lock); dns_db_overmem(cache->db, overmem); cache->cleaner.overmem = overmem; if (cache->cleaner.overmem_event != NULL) isc_task_send(cache->cleaner.task, &cache->cleaner.overmem_event); UNLOCK(&cache->cleaner.lock); } void dns_cache_setcachesize(dns_cache_t *cache, isc_uint32_t size) { isc_uint32_t lowater; isc_uint32_t hiwater; REQUIRE(VALID_CACHE(cache)); /* * Impose a minumum cache size; pathological things happen if there * is too little room. */ if (size != 0 && size < DNS_CACHE_MINSIZE) size = DNS_CACHE_MINSIZE; hiwater = size - (size >> 3); /* Approximately 7/8ths. */ lowater = size - (size >> 2); /* Approximately 3/4ths. */ /* * If the cache was overmem and cleaning, but now with the new limits * it is no longer in an overmem condition, then the next * isc_mem_put for cache memory will do the right thing and trigger * water(). */ if (size == 0 || hiwater == 0 || lowater == 0) /* * Disable cache memory limiting. */ isc_mem_setwater(cache->mctx, water, cache, 0, 0); else /* * Establish new cache memory limits (either for the first * time, or replacing other limits). */ isc_mem_setwater(cache->mctx, water, cache, hiwater, lowater); } /* * The cleaner task is shutting down; do the necessary cleanup. */ static void cleaner_shutdown_action(isc_task_t *task, isc_event_t *event) { dns_cache_t *cache = event->ev_arg; isc_boolean_t should_free = ISC_FALSE; UNUSED(task); INSIST(task == cache->cleaner.task); INSIST(event->ev_type == ISC_TASKEVENT_SHUTDOWN); if (CLEANER_BUSY(&cache->cleaner)) end_cleaning(&cache->cleaner, event); else isc_event_free(&event); LOCK(&cache->lock); cache->live_tasks--; INSIST(cache->live_tasks == 0); if (cache->references == 0) should_free = ISC_TRUE; /* * By detaching the timer in the context of its task, * we are guaranteed that there will be no further timer * events. */ if (cache->cleaner.cleaning_timer != NULL) isc_timer_detach(&cache->cleaner.cleaning_timer); /* Make sure we don't reschedule anymore. */ (void)isc_task_purge(task, NULL, DNS_EVENT_CACHECLEAN, NULL); UNLOCK(&cache->lock); if (should_free) cache_free(cache); } isc_result_t dns_cache_flush(dns_cache_t *cache) { dns_db_t *db = NULL; isc_result_t result; result = cache_create_db(cache, &db); if (result != ISC_R_SUCCESS) return (result); LOCK(&cache->lock); LOCK(&cache->cleaner.lock); if (cache->cleaner.state == cleaner_s_idle) { if (cache->cleaner.iterator != NULL) dns_dbiterator_destroy(&cache->cleaner.iterator); (void) dns_db_createiterator(db, ISC_FALSE, &cache->cleaner.iterator); } else { if (cache->cleaner.state == cleaner_s_busy) cache->cleaner.state = cleaner_s_done; cache->cleaner.replaceiterator = ISC_TRUE; } dns_db_detach(&cache->db); cache->db = db; UNLOCK(&cache->cleaner.lock); UNLOCK(&cache->lock); return (ISC_R_SUCCESS); } isc_result_t dns_cache_flushname(dns_cache_t *cache, dns_name_t *name) { isc_result_t result; dns_rdatasetiter_t *iter = NULL; dns_dbnode_t *node = NULL; dns_db_t *db = NULL; LOCK(&cache->lock); if (cache->db != NULL) dns_db_attach(cache->db, &db); UNLOCK(&cache->lock); if (db == NULL) return (ISC_R_SUCCESS); result = dns_db_findnode(cache->db, name, ISC_FALSE, &node); if (result == ISC_R_NOTFOUND) { result = ISC_R_SUCCESS; goto cleanup_db; } if (result != ISC_R_SUCCESS) goto cleanup_db; result = dns_db_allrdatasets(cache->db, node, NULL, (isc_stdtime_t)0, &iter); if (result != ISC_R_SUCCESS) goto cleanup_node; for (result = dns_rdatasetiter_first(iter); result == ISC_R_SUCCESS; result = dns_rdatasetiter_next(iter)) { dns_rdataset_t rdataset; dns_rdataset_init(&rdataset); dns_rdatasetiter_current(iter, &rdataset); result = dns_db_deleterdataset(cache->db, node, NULL, rdataset.type, rdataset.covers); dns_rdataset_disassociate(&rdataset); if (result != ISC_R_SUCCESS && result != DNS_R_UNCHANGED) break; } if (result == ISC_R_NOMORE) result = ISC_R_SUCCESS; dns_rdatasetiter_destroy(&iter); cleanup_node: dns_db_detachnode(cache->db, &node); cleanup_db: dns_db_detach(&db); return (result); }