2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License as published by
4 * the Free Software Foundation; either version 2 of the License, or
5 * (at your option) any later version.
7 * This program is distributed in the hope that it will be useful,
8 * but WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 * GNU General Public License for more details.
12 * You should have received a copy of the GNU General Public License
13 * along with this program; if not, write to the Free Software
14 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
19 * @brief Handle pools of connections (threads, sockets, etc.)
20 * @note This API must be used by all modules in the public distribution that
21 * maintain pools of connections.
23 * @copyright 2012 The FreeRADIUS server project
24 * @copyright 2012 Alan DeKok <aland@deployingradius.com>
28 #include <freeradius-devel/radiusd.h>
29 #include <freeradius-devel/rad_assert.h>
31 typedef struct fr_connection fr_connection_t;
33 static int fr_connection_pool_check(fr_connection_pool_t *pool);
35 extern bool check_config;
39 /* #define PTHREAD_DEBUG (1) */
43 /** An individual connection within the connection pool
45 * Defines connection counters, timestamps, and holds a pointer to the
46 * connection handle itself.
48 * @see fr_connection_pool_t
50 struct fr_connection {
51 fr_connection_t *prev; //!< Previous connection in list.
52 fr_connection_t *next; //!< Next connection in list.
54 time_t created; //!< Time connection was created.
55 time_t last_used; //!< Last time the connection was
58 uint32_t num_uses; //!< Number of times the connection
59 //!< has been reserved.
60 uint64_t number; //!< Unique ID assigned when the
61 //!< connection is created, these will
62 //!< monotonically increase over the
63 //!< lifetime of the connection pool.
64 void *connection; //!< Pointer to whatever the module
65 //!< uses for a connection handle.
66 bool in_use; //!< Whether the connection is currently
69 pthread_t pthread_id; //!< When 'in_use == true'
75 * Defines the configuration of the connection pool, all the counters and
76 * timestamps related to the connection pool, the mutex that stops multiple
77 * threads leaving the pool in an inconsistent state, and the callbacks
78 * required to open, close and check the status of connections within the pool.
82 struct fr_connection_pool_t {
83 uint32_t start; //!< Number of initial connections
84 uint32_t min; //!< Minimum number of concurrent
85 //!< connections to keep open.
86 uint32_t max; //!< Maximum number of concurrent
87 //!< connections to allow.
88 uint32_t spare; //!< Number of spare connections to try
89 int retry_delay; //!< seconds to delay re-open
90 //!< after a failed open.
91 uint32_t cleanup_interval; //!< Initial timer for how
92 //!< often we sweep the pool
93 //!< for free connections.
95 int delay_interval; //!< When we next do a
96 //!< cleanup. Initialized to
97 //!< cleanup_interval, and increase
98 //!< from there based on the delay.
99 int next_delay; //!< The next delay time.
100 //!< cleanup. Initialized to
101 //!< cleanup_interval, and decays
103 uint32_t max_uses; //!< Maximum number of times a
104 //!< connection can be used before being
106 uint32_t lifetime; //!< How long a connection can be open
107 //!< before being closed (irrespective
108 //!< of whether it's idle or not).
109 uint32_t idle_timeout; //!< How long a connection can be idle
110 //!< before being closed.
112 bool trigger; //!< If true execute connection triggers
113 //!< associated with the connection
116 bool spread; //!< If true requests will be spread
117 //!< across all connections, instead of
118 //!< re-using the most recently used
119 //!< connections first.
121 time_t last_checked; //!< Last time we pruned the connection
123 time_t last_spawned; //!< Last time we spawned a connection.
124 time_t last_failed; //!< Last time we tried to spawn a
125 //!< a connection but failed.
126 time_t last_throttled; //!< Last time we refused to spawn a
127 //!< connection because the last
128 //!< connection failed, or we were
129 //!< already spawning a connection.
130 time_t last_at_max; //!< Last time we hit the maximum number
131 //!< of allowed connections.
133 uint64_t count; //!< Number of connections spawned over
134 //!< the lifetime of the pool.
135 uint32_t num; //!< Number of connections in the pool.
136 int active; //!< Number of currently reserved
139 fr_connection_t *head; //!< Start of the connection list.
140 fr_connection_t *tail; //!< End of the connection list.
142 bool spawning; //!< Whether we are currently attempting
143 //!< to spawn a new connection.
145 #ifdef HAVE_PTHREAD_H
146 pthread_mutex_t mutex; //!< Mutex used to keep consistent state
147 //!< when making modifications in
151 CONF_SECTION *cs; //!< Configuration section holding
152 //!< the section of parsed config file
153 //!< that relates to this pool.
154 void *ctx; //!< Pointer to context data that will
155 //!< be passed to callbacks.
157 char *log_prefix; //!< Log prefix to prepend to all log
158 //!< messages created by the connection
161 fr_connection_create_t create; //!< Function used to create new
163 fr_connection_alive_t alive; //!< Function used to check status
165 fr_connection_delete_t delete; //!< Function used to close existing
169 #define LOG_PREFIX "rlm_%s (%s)"
170 #ifndef HAVE_PTHREAD_H
171 #define pthread_mutex_lock(_x)
172 #define pthread_mutex_unlock(_x)
175 static const CONF_PARSER connection_config[] = {
176 { "start", FR_CONF_OFFSET(PW_TYPE_INTEGER, fr_connection_pool_t, start), "5" },
177 { "min", PW_TYPE_INTEGER, offsetof(fr_connection_pool_t, min),
179 { "max", PW_TYPE_INTEGER, offsetof(fr_connection_pool_t, max),
181 { "spare", PW_TYPE_INTEGER, offsetof(fr_connection_pool_t, spare),
183 { "uses", PW_TYPE_INTEGER, offsetof(fr_connection_pool_t, max_uses),
185 { "lifetime", PW_TYPE_INTEGER, offsetof(fr_connection_pool_t, lifetime),
187 { "cleanup_delay", PW_TYPE_INTEGER, offsetof(fr_connection_pool_t, cleanup_interval),
189 { "cleanup_interval", PW_TYPE_INTEGER, offsetof(fr_connection_pool_t, cleanup_interval),
191 { "idle_timeout", PW_TYPE_INTEGER, offsetof(fr_connection_pool_t, idle_timeout),
193 { "retry_delay", PW_TYPE_INTEGER, offsetof(fr_connection_pool_t, retry_delay),
195 { "spread", PW_TYPE_BOOLEAN, offsetof(fr_connection_pool_t, spread),
197 { NULL, -1, 0, NULL, NULL }
200 /** Removes a connection from the connection list
202 * @note Must be called with the mutex held.
204 * @param[in,out] pool to modify.
205 * @param[in] this Connection to delete.
207 static void fr_connection_unlink(fr_connection_pool_t *pool,
208 fr_connection_t *this)
211 rad_assert(pool->head != this);
212 this->prev->next = this->next;
214 rad_assert(pool->head == this);
215 pool->head = this->next;
218 rad_assert(pool->tail != this);
219 this->next->prev = this->prev;
221 rad_assert(pool->tail == this);
222 pool->tail = this->prev;
225 this->prev = this->next = NULL;
228 /** Adds a connection to the head of the connection list
230 * @note Must be called with the mutex held.
232 * @param[in,out] pool to modify.
233 * @param[in] this Connection to add.
235 static void fr_connection_link_head(fr_connection_pool_t *pool,
236 fr_connection_t *this)
238 rad_assert(pool != NULL);
239 rad_assert(this != NULL);
240 rad_assert(pool->head != this);
241 rad_assert(pool->tail != this);
244 pool->head->prev = this;
247 this->next = pool->head;
251 rad_assert(this->next == NULL);
254 rad_assert(this->next != NULL);
258 /** Adds a connection to the tail of the connection list
260 * @note Must be called with the mutex held.
262 * @param[in,out] pool to modify.
263 * @param[in] this Connection to add.
265 static void fr_connection_link_tail(fr_connection_pool_t *pool,
266 fr_connection_t *this)
268 rad_assert(pool != NULL);
269 rad_assert(this != NULL);
270 rad_assert(pool->head != this);
271 rad_assert(pool->tail != this);
274 pool->tail->next = this;
276 this->prev = pool->tail;
280 rad_assert(this->prev == NULL);
283 rad_assert(this->prev != NULL);
288 /** Spawns a new connection
290 * Spawns a new connection using the create callback, and returns it for
291 * adding to the connection list.
293 * @note Will call the 'open' trigger.
294 * @note Must be called with the mutex free.
296 * @param[in] pool to modify.
297 * @param[in] now Current time.
298 * @param[in] in_use whether the new connection should be "in_use" or not
299 * @return the new connection struct or NULL on error.
301 static fr_connection_t *fr_connection_spawn(fr_connection_pool_t *pool,
302 time_t now, bool in_use)
304 fr_connection_t *this;
307 rad_assert(pool != NULL);
310 * Prevent all threads from blocking if the resource
311 * were managing connections for appears to be unavailable.
313 if ((pool->num == 0) && pool->spawning) {
317 pthread_mutex_lock(&pool->mutex);
318 rad_assert(pool->num <= pool->max);
321 * Don't spawn multiple connections at the same time.
323 if (pool->spawning) {
324 pthread_mutex_unlock(&pool->mutex);
326 ERROR("%s: Cannot open new connection, "
327 "connection spawning already in "
328 "progress", pool->log_prefix);
333 * If the last attempt failed, wait a bit before
336 if (pool->last_failed && ((pool->last_failed + pool->retry_delay) > now)) {
337 bool complain = false;
339 if (pool->last_throttled != now) {
342 pool->last_throttled = now;
345 pthread_mutex_unlock(&pool->mutex);
347 if (!RATE_LIMIT_ENABLED || complain) {
348 ERROR("%s: Last connection attempt failed, waiting %d seconds before retrying",
349 pool->log_prefix, pool->retry_delay);
355 pool->spawning = true;
358 * Unlock the mutex while we try to open a new
359 * connection. If there are issues with the back-end,
360 * opening a new connection may take a LONG time. In
361 * that case, we want the other connections to continue
364 pthread_mutex_unlock(&pool->mutex);
366 INFO("%s: Opening additional connection (%" PRIu64 ")", pool->log_prefix, pool->count);
369 * This may take a long time, which prevents other
370 * threads from releasing connections. We don't care
371 * about other threads opening new connections, as we
372 * already have no free connections.
374 conn = pool->create(pool->ctx);
376 ERROR("%s: Opening connection failed (%" PRIu64 ")", pool->log_prefix, pool->count);
378 pool->last_failed = now;
379 pool->spawning = false; /* atomic, so no lock is needed */
384 * And lock the mutex again while we link the new
385 * connection back into the pool.
387 pthread_mutex_lock(&pool->mutex);
389 this = talloc_zero(pool, fr_connection_t);
391 pthread_mutex_unlock(&pool->mutex);
396 this->connection = conn;
397 this->in_use = in_use;
399 this->number = pool->count++;
400 this->last_used = now;
401 fr_connection_link_head(pool, this);
403 pool->spawning = false;
404 pool->last_spawned = time(NULL);
405 pool->delay_interval = pool->cleanup_interval;
406 pool->next_delay = pool->cleanup_interval;
407 pool->last_failed = 0;
409 pthread_mutex_unlock(&pool->mutex);
411 if (pool->trigger) exec_trigger(NULL, pool->cs, "open", true);
416 /** Close an existing connection.
418 * Removes the connection from the list, calls the delete callback to close
419 * the connection, then frees memory allocated to the connection.
421 * @note Will call the 'close' trigger.
422 * @note Must be called with the mutex held.
424 * @param[in,out] pool to modify.
425 * @param[in,out] this Connection to delete.
428 static void fr_connection_close(fr_connection_pool_t *pool,
429 fr_connection_t *this)
432 * If it's in use, release it.
436 pthread_t pthread_id = pthread_self();
437 rad_assert(pthread_equal(this->pthread_id, pthread_id) != 0);
439 this->in_use = false;
441 rad_assert(pool->active > 0);
445 if (pool->trigger) exec_trigger(NULL, pool->cs, "close", true);
447 fr_connection_unlink(pool, this);
448 pool->delete(pool->ctx, this->connection);
449 rad_assert(pool->num > 0);
454 /** Find a connection handle in the connection list
456 * Walks over the list of connections searching for a specified connection
457 * handle and returns the first connection that contains that pointer.
459 * @note Will lock mutex and only release mutex if connection handle
460 * is not found, so will usually return will mutex held.
461 * @note Must be called with the mutex free.
463 * @param[in] pool to search in.
464 * @param[in] conn handle to search for.
465 * @return the connection containing the specified handle, or NULL if non is
468 static fr_connection_t *fr_connection_find(fr_connection_pool_t *pool, void *conn)
470 fr_connection_t *this;
472 if (!pool || !conn) return NULL;
474 pthread_mutex_lock(&pool->mutex);
477 * FIXME: This loop could be avoided if we passed a 'void
478 * **connection' instead. We could use "offsetof" in
479 * order to find top of the parent structure.
481 for (this = pool->head; this != NULL; this = this->next) {
482 if (this->connection == conn) {
484 pthread_t pthread_id;
486 pthread_id = pthread_self();
487 rad_assert(pthread_equal(this->pthread_id, pthread_id) != 0);
490 rad_assert(this->in_use == true);
495 pthread_mutex_unlock(&pool->mutex);
499 /** Delete a connection from the connection pool.
501 * Resolves the connection handle to a connection, then (if found)
502 * closes, unlinks and frees that connection.
504 * @note Must be called with the mutex free.
506 * @param[in,out] pool Connection pool to modify.
507 * @param[in] conn to delete.
508 * @return 0 if the connection could not be found, else 1.
510 int fr_connection_del(fr_connection_pool_t *pool, void *conn)
512 fr_connection_t *this;
514 this = fr_connection_find(pool, conn);
517 INFO("%s: Deleting connection (%" PRIu64 ")", pool->log_prefix, this->number);
519 fr_connection_close(pool, this);
520 fr_connection_pool_check(pool);
524 /** Delete a connection pool
526 * Closes, unlinks and frees all connections in the connection pool, then frees
527 * all memory used by the connection pool.
529 * @note Will call the 'stop' trigger.
530 * @note Must be called with the mutex free.
532 * @param[in,out] pool to delete.
534 void fr_connection_pool_delete(fr_connection_pool_t *pool)
536 fr_connection_t *this, *next;
540 DEBUG("%s: Removing connection pool", pool->log_prefix);
542 pthread_mutex_lock(&pool->mutex);
544 for (this = pool->head; this != NULL; this = next) {
547 INFO("%s: Closing connection (%" PRIu64 ")", pool->log_prefix, this->number);
549 fr_connection_close(pool, this);
552 if (pool->trigger) exec_trigger(NULL, pool->cs, "stop", true);
554 rad_assert(pool->head == NULL);
555 rad_assert(pool->tail == NULL);
556 rad_assert(pool->num == 0);
561 /** Create a new connection pool
563 * Allocates structures used by the connection pool, initialises the various
564 * configuration options and counters, and sets the callback functions.
566 * Will also spawn the number of connections specified by the 'start'
567 * configuration options.
569 * @note Will call the 'start' trigger.
571 * @param[in] parent configuration section containing a 'pool' subsection.
572 * @param[in] ctx pointer to pass to callbacks.
573 * @param[in] c Callback to create new connections.
574 * @param[in] a Callback to check the status of connections.
575 * @param[in] d Callback to delete connections.
576 * @param[in] prefix to prepend to all log message, if NULL will create prefix
577 * from parent conf section names.
578 * @return A new connection pool or NULL on error.
580 fr_connection_pool_t *fr_connection_pool_init(CONF_SECTION *parent,
582 fr_connection_create_t c,
583 fr_connection_alive_t a,
584 fr_connection_delete_t d,
588 fr_connection_pool_t *pool;
589 fr_connection_t *this;
590 CONF_SECTION *modules;
592 char const *cs_name1, *cs_name2;
593 time_t now = time(NULL);
595 if (!parent || !ctx || !c || !d) return NULL;
597 cs = cf_section_sub_find(parent, "pool");
598 if (!cs) cs = cf_section_sub_find(parent, "limit");
601 pool = talloc_zero(cs, fr_connection_pool_t);
603 pool = talloc_zero(parent, fr_connection_pool_t);
605 if (!pool) return NULL;
613 pool->head = pool->tail = NULL;
615 #ifdef HAVE_PTHREAD_H
616 pthread_mutex_init(&pool->mutex, NULL);
620 modules = cf_item_parent(cf_sectiontoitem(parent));
622 cs_name1 = cf_section_name1(modules);
623 if (cs_name1 && (strcmp(cs_name1, "modules") == 0)) {
624 cs_name1 = cf_section_name1(parent);
625 cs_name2 = cf_section_name2(parent);
630 pool->log_prefix = talloc_typed_asprintf(pool, LOG_PREFIX, cs_name1,
633 } else { /* not a module configuration */
634 cs_name1 = cf_section_name1(parent);
636 pool->log_prefix = talloc_typed_strdup(pool, cs_name1);
639 pool->log_prefix = talloc_typed_strdup(pool, prefix);
642 DEBUG("%s: Initialising connection pool", pool->log_prefix);
645 if (cf_section_parse(cs, pool, connection_config) < 0) {
649 if (cf_section_sub_find(cs, "trigger")) pool->trigger = true;
655 pool->cleanup_interval = 30;
656 pool->idle_timeout = 60;
662 if (pool->max == 0) {
663 cf_log_err_cs(cs, "Cannot set 'max' to zero");
666 if (pool->min > pool->max) {
667 cf_log_err_cs(cs, "Cannot set 'min' to more than 'max'");
671 if (pool->max > 1024) pool->max = 1024;
672 if (pool->start > pool->max) pool->start = pool->max;
673 if (pool->spare > (pool->max - pool->min)) {
674 pool->spare = pool->max - pool->min;
676 if ((pool->lifetime > 0) && (pool->idle_timeout > pool->lifetime)) {
677 pool->idle_timeout = 0;
680 if ((pool->idle_timeout > 0) && (pool->cleanup_interval > pool->idle_timeout)) {
681 pool->cleanup_interval = pool->idle_timeout;
685 * Don't open any connections. Instead, force the limits
686 * to only 1 connection.
690 pool->start = pool->min = pool->max = 1;
695 * Create all of the connections, unless the admin says
698 for (i = 0; i < pool->start; i++) {
699 this = fr_connection_spawn(pool, now, false);
702 fr_connection_pool_delete(pool);
707 if (pool->trigger) exec_trigger(NULL, pool->cs, "start", true);
713 /** Check whether a connection needs to be removed from the pool
715 * Will verify that the connection is within idle_timeout, max_uses, and
716 * lifetime values. If it is not, the connection will be closed.
718 * @note Will only close connections not in use.
719 * @note Must be called with the mutex held.
721 * @param[in,out] pool to modify.
722 * @param[in,out] this Connection to manage.
723 * @param[in] now Current time.
724 * @return 0 if the connection was closed, otherwise 1.
726 static int fr_connection_manage(fr_connection_pool_t *pool,
727 fr_connection_t *this,
730 rad_assert(pool != NULL);
731 rad_assert(this != NULL);
734 * Don't terminated in-use connections
736 if (this->in_use) return 1;
738 if ((pool->max_uses > 0) &&
739 (this->num_uses >= pool->max_uses)) {
740 DEBUG("%s: Closing expired connection (%" PRIu64 "): Hit max_uses limit", pool->log_prefix,
743 if (pool->num <= pool->min) {
744 RATE_LIMIT(WARN("%s: You probably need to lower \"min\"", pool->log_prefix));
746 fr_connection_close(pool, this);
750 if ((pool->lifetime > 0) &&
751 ((this->created + pool->lifetime) < now)) {
752 DEBUG("%s: Closing expired connection (%" PRIu64 ")", pool->log_prefix, this->number);
756 if ((pool->idle_timeout > 0) &&
757 ((this->last_used + pool->idle_timeout) < now)) {
758 INFO("%s: Closing connection (%" PRIu64 "): Hit idle_timeout, was idle for %u seconds",
759 pool->log_prefix, this->number, (int) (now - this->last_used));
767 /** Check whether any connections needs to be removed from the pool
769 * Maintains the number of connections in the pool as per the configuration
770 * parameters for the connection pool.
772 * @note Will only run checks the first time it's called in a given second,
773 * to throttle connection spawning/closing.
774 * @note Will only close connections not in use.
775 * @note Must be called with the mutex held, will release mutex before
778 * @param[in,out] pool to manage.
781 static int fr_connection_pool_check(fr_connection_pool_t *pool)
783 uint32_t spawn, idle, extra;
784 time_t now = time(NULL);
785 fr_connection_t *this, *next;
787 if (pool->last_checked == now) {
788 pthread_mutex_unlock(&pool->mutex);
793 * Some idle connections are OK, if they're within the
794 * configured "spare" range. Any extra connections
795 * outside of that range can be closed.
797 idle = pool->num - pool->active;
798 if (idle <= pool->spare) {
801 extra = idle - pool->spare;
805 * The other end can close connections. If so, we'll
806 * have fewer than "min". When that happens, open more
807 * connections to enforce "min".
809 if (pool->num <= pool->min) {
810 if (pool->spawning) {
813 spawn = pool->min - pool->num;
817 } else if (pool->num >= pool->max) {
819 * Ensure we don't spawn more connections. If
820 * there are extra idle connections, we can
821 * delete all of them.
824 /* leave extra alone from above */
826 } else if (idle <= pool->spare) {
828 * Not enough spare connections. Spawn a few.
829 * But cap the pool size at "max"
831 spawn = pool->spare - idle;
834 if ((pool->num + spawn) > pool->max) {
835 spawn = pool->max - pool->num;
838 } else if ((pool->min + extra) >= pool->num) {
840 * If closing the extra connections would take us
841 * below "min", then don't do that. Cap the
842 * spare connections at the ones which will take
843 * us exactly to "min".
846 extra = pool->num - pool->min;
850 * Closing the "extra" connections won't take us
851 * below "min". It's therefore safe to close
855 /* leave extra alone from above */
859 pthread_mutex_unlock(&pool->mutex);
860 fr_connection_spawn(pool, now, false); /* ignore return code */
861 pthread_mutex_lock(&pool->mutex);
865 * We haven't spawned connections in a while, and there
866 * are too many spare ones. Close the one which has been
867 * unused for the longest.
869 if (extra && (now >= (pool->last_spawned + pool->delay_interval))) {
870 fr_connection_t *found;
873 for (this = pool->tail; this != NULL; this = this->prev) {
874 if (this->in_use) continue;
877 (this->last_used < found->last_used)) {
882 rad_assert(found != NULL);
884 INFO("%s: Closing connection (%" PRIu64 "), from %d unused connections", pool->log_prefix,
885 found->number, extra);
886 fr_connection_close(pool, found);
889 * Decrease the delay for the next time we clean
892 pool->next_delay >>= 1;
893 if (pool->next_delay == 0) pool->next_delay = 1;
894 pool->delay_interval += pool->next_delay;
898 * Pass over all of the connections in the pool, limiting
899 * lifetime, idle time, max requests, etc.
901 for (this = pool->head; this != NULL; this = next) {
903 fr_connection_manage(pool, this, now);
906 pool->last_checked = now;
907 pthread_mutex_unlock(&pool->mutex);
912 /** Get a connection from the connection pool
914 * @param[in,out] pool to reserve the connection from.
915 * @param[in] spawn whether to spawn a new connection
916 * @return a pointer to the connection handle, or NULL on error.
918 static void *fr_connection_get_internal(fr_connection_pool_t *pool, int spawn)
921 fr_connection_t *this, *next;
923 if (!pool) return NULL;
925 pthread_mutex_lock(&pool->mutex);
928 for (this = pool->head; this != NULL; this = next) {
931 if (!this->in_use) goto do_return;
934 if (pool->num == pool->max) {
935 bool complain = false;
938 * Rate-limit complaints.
940 if (pool->last_at_max != now) {
942 pool->last_at_max = now;
945 pthread_mutex_unlock(&pool->mutex);
947 if (!RATE_LIMIT_ENABLED || complain) {
948 ERROR("%s: No connections available and at max connection limit", pool->log_prefix);
954 pthread_mutex_unlock(&pool->mutex);
956 if (!spawn) return NULL;
958 this = fr_connection_spawn(pool, now, true); /* MY connection! */
959 if (!this) return NULL;
960 pthread_mutex_lock(&pool->mutex);
965 this->last_used = now;
969 this->pthread_id = pthread_self();
971 pthread_mutex_unlock(&pool->mutex);
973 DEBUG("%s: Reserved connection (%" PRIu64 ")", pool->log_prefix, this->number);
975 return this->connection;
979 /** Reserve a connection in the connection pool
981 * Will attempt to find an unused connection in the connection pool, if one is
982 * found, will mark it as in in use increment the number of active connections
983 * and return the connection handle.
985 * If no free connections are found will attempt to spawn a new one, conditional
986 * on a connection spawning not already being in progress, and not being at the
987 * 'max' connection limit.
989 * @note fr_connection_release must be called once the caller has finished
990 * using the connection.
992 * @see fr_connection_release
993 * @param[in,out] pool to reserve the connection from.
994 * @return a pointer to the connection handle, or NULL on error.
996 void *fr_connection_get(fr_connection_pool_t *pool)
998 return fr_connection_get_internal(pool, true);
1001 /** Get the number of connections currently in the pool
1003 * @param pool to count connections for.
1004 * @return the number of connections in the pool
1006 int fr_connection_get_num(fr_connection_pool_t *pool)
1011 /** Release a connection
1013 * Will mark a connection as unused and decrement the number of active
1016 * @see fr_connection_get
1017 * @param[in,out] pool to release the connection in.
1018 * @param[in,out] conn to release.
1020 void fr_connection_release(fr_connection_pool_t *pool, void *conn)
1022 fr_connection_t *this;
1024 this = fr_connection_find(pool, conn);
1027 this->in_use = false;
1030 * Determines whether the last used connection gets
1035 * Put it at the tail of the list, so
1036 * that it will get re-used last.
1038 if (this != pool->tail) {
1039 fr_connection_unlink(pool, this);
1040 fr_connection_link_tail(pool, this);
1044 * Put it at the head of the list, so
1045 * that it will get re-used quickly.
1047 if (this != pool->head) {
1048 fr_connection_unlink(pool, this);
1049 fr_connection_link_head(pool, this);
1053 rad_assert(pool->active > 0);
1056 DEBUG("%s: Released connection (%" PRIu64 ")", pool->log_prefix, this->number);
1059 * We mirror the "spawn on get" functionality by having
1060 * "delete on release". If there are too many spare
1061 * connections, go manage the pool && clean some up.
1063 fr_connection_pool_check(pool);
1066 /** Reconnect a suspected inviable connection
1068 * This should be called by the module if it suspects that a connection is
1069 * not viable (e.g. the server has closed it).
1071 * Will attempt to create a new connection handle using the create callback,
1072 * and if this is successful the new handle will be assigned to the existing
1075 * If this is not successful, the connection will be removed from the pool.
1077 * When implementing a module that uses the connection pool API, it is advisable
1078 * to pass a pointer to the pointer to the handle (void **conn)
1079 * to all functions which may call reconnect. This is so that if a new handle
1080 * is created and returned, the handle pointer can be updated up the callstack,
1081 * and a function higher up the stack doesn't attempt to use a now invalid
1082 * connection handle.
1084 * @warning After calling reconnect the caller *MUST NOT* attempt to use
1085 * the old handle in any other operations, as its memory will have been freed.
1087 * @see fr_connection_get
1088 * @param[in,out] pool to reconnect the connection in.
1089 * @param[in,out] conn to reconnect.
1090 * @return new connection handle if successful else NULL.
1092 void *fr_connection_reconnect(fr_connection_pool_t *pool, void *conn)
1095 fr_connection_t *this;
1096 uint64_t conn_number;
1098 if (!pool || !conn) return NULL;
1100 this = fr_connection_find(pool, conn);
1101 if (!this) return NULL;
1104 * The pool is now locked.
1106 conn_number = this->number;
1108 DEBUG("%s: Reconnecting (%" PRIu64 ")", pool->log_prefix, conn_number);
1110 new_conn = pool->create(pool->ctx);
1113 * We can't create a new connection, so close
1116 fr_connection_close(pool, this);
1119 * Maybe there's a connection which is unused and
1120 * available. If so, return it.
1122 pthread_mutex_unlock(&pool->mutex);
1123 new_conn = fr_connection_get_internal(pool, false);
1124 if (new_conn) return new_conn;
1126 RATE_LIMIT(ERROR("%s: Failed to reconnect (%" PRIu64 "), no free connections are available", pool->log_prefix,
1131 if (pool->trigger) exec_trigger(NULL, pool->cs, "close", true);
1132 pool->delete(pool->ctx, conn);
1133 this->connection = new_conn;
1134 pthread_mutex_unlock(&pool->mutex);