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-rw-r--r--lib/dns/cache.c1154
1 files changed, 1154 insertions, 0 deletions
diff --git a/lib/dns/cache.c b/lib/dns/cache.c
new file mode 100644
index 0000000..011dbf7
--- /dev/null
+++ b/lib/dns/cache.c
@@ -0,0 +1,1154 @@
+/*
+ * 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.
+ */
+
+/* $Id: cache.c,v 1.57.18.16 2006/08/01 01:06:48 marka Exp $ */
+
+/*! \file */
+
+#include <config.h>
+
+#include <isc/mem.h>
+#include <isc/task.h>
+#include <isc/time.h>
+#include <isc/timer.h>
+#include <isc/util.h>
+
+#include <dns/cache.h>
+#include <dns/db.h>
+#include <dns/dbiterator.h>
+#include <dns/events.h>
+#include <dns/lib.h>
+#include <dns/log.h>
+#include <dns/masterdump.h>
+#include <dns/rdata.h>
+#include <dns/rdataset.h>
+#include <dns/rdatasetiter.h>
+#include <dns/result.h>
+
+#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);
+}
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