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connection.c
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connection.c
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/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
*/
/**
* @file connection.c
* @brief Handle pools of connections (threads, sockets, etc.)
* @note This API must be used by all modules in the public distribution that
* maintain pools of connections.
*
* @copyright 2012 The FreeRADIUS server project
* @copyright 2012 Alan DeKok <aland@deployingradius.com>
*/
RCSID("$Id$")
#include <freeradius-devel/radiusd.h>
#include <freeradius-devel/modpriv.h>
#include <freeradius-devel/rad_assert.h>
typedef struct fr_connection fr_connection_t;
static int fr_connection_pool_check(fr_connection_pool_t *pool);
#ifndef NDEBUG
#ifdef HAVE_PTHREAD_H
/* #define PTHREAD_DEBUG (1) */
#endif
#endif
/** An individual connection within the connection pool
*
* Defines connection counters, timestamps, and holds a pointer to the
* connection handle itself.
*
* @see fr_connection_pool_t
*/
struct fr_connection {
fr_connection_t *prev; //!< Previous connection in list.
fr_connection_t *next; //!< Next connection in list.
time_t created; //!< Time connection was created.
time_t last_used; //!< Last time the connection was
//!< reserved.
uint32_t num_uses; //!< Number of times the connection
//!< has been reserved.
uint64_t number; //!< Unique ID assigned when the
//!< connection is created, these will
//!< monotonically increase over the
//!< lifetime of the connection pool.
void *connection; //!< Pointer to whatever the module
//!< uses for a connection handle.
bool in_use; //!< Whether the connection is currently
//!< reserved.
#ifdef PTHREAD_DEBUG
pthread_t pthread_id; //!< When 'in_use == true'
#endif
};
/** A connection pool
*
* Defines the configuration of the connection pool, all the counters and
* timestamps related to the connection pool, the mutex that stops multiple
* threads leaving the pool in an inconsistent state, and the callbacks
* required to open, close and check the status of connections within the pool.
*
* @see fr_connection
*/
struct fr_connection_pool_t {
uint32_t start; //!< Number of initial connections
uint32_t min; //!< Minimum number of concurrent
//!< connections to keep open.
uint32_t max; //!< Maximum number of concurrent
//!< connections to allow.
uint32_t spare; //!< Number of spare connections to try
uint32_t pending; //!< Number of pending open connections
uint32_t retry_delay; //!< seconds to delay re-open
//!< after a failed open.
uint32_t cleanup_interval; //!< Initial timer for how
//!< often we sweep the pool
//!< for free connections.
//!< (0 is infinite).
int delay_interval; //!< When we next do a
//!< cleanup. Initialized to
//!< cleanup_interval, and increase
//!< from there based on the delay.
int next_delay; //!< The next delay time.
//!< cleanup. Initialized to
//!< cleanup_interval, and decays
//!< from there.
uint64_t max_uses; //!< Maximum number of times a
//!< connection can be used before being
//!< closed.
uint32_t lifetime; //!< How long a connection can be open
//!< before being closed (irrespective
//!< of whether it's idle or not).
uint32_t idle_timeout; //!< How long a connection can be idle
//!< before being closed.
bool spread; //!< If true requests will be spread
//!< across all connections, instead of
//!< re-using the most recently used
//!< connections first.
time_t last_checked; //!< Last time we pruned the connection
//!< pool.
time_t last_spawned; //!< Last time we spawned a connection.
time_t last_failed; //!< Last time we tried to spawn a
//!< a connection but failed.
time_t last_throttled; //!< Last time we refused to spawn a
//!< connection because the last
//!< connection failed, or we were
//!< already spawning a connection.
time_t last_at_max; //!< Last time we hit the maximum number
//!< of allowed connections.
uint32_t max_pending; //!< Max number of connections to open
uint64_t count; //!< Number of connections spawned over
//!< the lifetime of the pool.
uint32_t num; //!< Number of connections in the pool.
uint32_t active; //!< Number of currently reserved connections.
fr_connection_t *head; //!< Start of the connection list.
fr_connection_t *tail; //!< End of the connection list.
#ifdef HAVE_PTHREAD_H
pthread_mutex_t mutex; //!< Mutex used to keep consistent state
//!< when making modifications in
//!< threaded mode.
#endif
CONF_SECTION *cs; //!< Configuration section holding
//!< the section of parsed config file
//!< that relates to this pool.
void *opaque; //!< Pointer to context data that will
//!< be passed to callbacks.
char const *log_prefix; //!< Log prefix to prepend to all log
//!< messages created by the connection
//!< pool code.
char const *trigger_prefix; //!< Prefix to prepend to
//!< names of all triggers
//!< fired by the connection
//!< pool code.
fr_connection_create_t create; //!< Function used to create new
//!< connections.
fr_connection_alive_t alive; //!< Function used to check status
//!< of connections.
};
#ifndef HAVE_PTHREAD_H
#define pthread_mutex_lock(_x)
#define pthread_mutex_unlock(_x)
#endif
static const CONF_PARSER connection_config[] = {
{ "start", FR_CONF_OFFSET(PW_TYPE_INTEGER, fr_connection_pool_t, start), "5" },
{ "min", FR_CONF_OFFSET(PW_TYPE_INTEGER, fr_connection_pool_t, min), "5" },
{ "max", FR_CONF_OFFSET(PW_TYPE_INTEGER, fr_connection_pool_t, max), "10" },
{ "spare", FR_CONF_OFFSET(PW_TYPE_INTEGER, fr_connection_pool_t, spare), "3" },
{ "uses", FR_CONF_OFFSET(PW_TYPE_INTEGER64, fr_connection_pool_t, max_uses), "0" },
{ "lifetime", FR_CONF_OFFSET(PW_TYPE_INTEGER, fr_connection_pool_t, lifetime), "0" },
{ "cleanup_delay", FR_CONF_OFFSET(PW_TYPE_INTEGER, fr_connection_pool_t, cleanup_interval), NULL},
{ "cleanup_interval", FR_CONF_OFFSET(PW_TYPE_INTEGER, fr_connection_pool_t, cleanup_interval), "30" },
{ "idle_timeout", FR_CONF_OFFSET(PW_TYPE_INTEGER, fr_connection_pool_t, idle_timeout), "60" },
{ "retry_delay", FR_CONF_OFFSET(PW_TYPE_INTEGER, fr_connection_pool_t, retry_delay), "1" },
{ "spread", FR_CONF_OFFSET(PW_TYPE_BOOLEAN, fr_connection_pool_t, spread), "no" },
{ NULL, -1, 0, NULL, NULL }
};
/** Removes a connection from the connection list
*
* @note Must be called with the mutex held.
*
* @param[in,out] pool to modify.
* @param[in] this Connection to delete.
*/
static void fr_connection_unlink(fr_connection_pool_t *pool,
fr_connection_t *this)
{
if (this->prev) {
rad_assert(pool->head != this);
this->prev->next = this->next;
} else {
rad_assert(pool->head == this);
pool->head = this->next;
}
if (this->next) {
rad_assert(pool->tail != this);
this->next->prev = this->prev;
} else {
rad_assert(pool->tail == this);
pool->tail = this->prev;
}
this->prev = this->next = NULL;
}
/** Adds a connection to the head of the connection list
*
* @note Must be called with the mutex held.
*
* @param[in,out] pool to modify.
* @param[in] this Connection to add.
*/
static void fr_connection_link_head(fr_connection_pool_t *pool,
fr_connection_t *this)
{
rad_assert(pool != NULL);
rad_assert(this != NULL);
rad_assert(pool->head != this);
rad_assert(pool->tail != this);
if (pool->head) {
pool->head->prev = this;
}
this->next = pool->head;
this->prev = NULL;
pool->head = this;
if (!pool->tail) {
rad_assert(this->next == NULL);
pool->tail = this;
} else {
rad_assert(this->next != NULL);
}
}
/** Adds a connection to the tail of the connection list
*
* @note Must be called with the mutex held.
*
* @param[in,out] pool to modify.
* @param[in] this Connection to add.
*/
static void fr_connection_link_tail(fr_connection_pool_t *pool,
fr_connection_t *this)
{
rad_assert(pool != NULL);
rad_assert(this != NULL);
rad_assert(pool->head != this);
rad_assert(pool->tail != this);
if (pool->tail) {
pool->tail->next = this;
}
this->prev = pool->tail;
this->next = NULL;
pool->tail = this;
if (!pool->head) {
rad_assert(this->prev == NULL);
pool->head = this;
} else {
rad_assert(this->prev != NULL);
}
}
/** Send a connection pool trigger.
*
* @param[in] pool to send trigger for.
* @param[in] name_suffix trigger name suffix.
*/
static void fr_connection_exec_trigger(fr_connection_pool_t *pool,
char const *name_suffix)
{
char name[64];
rad_assert(pool != NULL);
rad_assert(name_suffix != NULL);
snprintf(name, sizeof(name), "%s%s", pool->trigger_prefix, name_suffix);
exec_trigger(NULL, pool->cs, name, true);
}
/** Spawns a new connection
*
* Spawns a new connection using the create callback, and returns it for
* adding to the connection list.
*
* @note Will call the 'open' trigger.
* @note Must be called with the mutex free.
*
* @param[in] pool to modify.
* @param[in] now Current time.
* @param[in] in_use whether the new connection should be "in_use" or not
* @return the new connection struct or NULL on error.
*/
static fr_connection_t *fr_connection_spawn(fr_connection_pool_t *pool,
time_t now, bool in_use)
{
uint64_t number;
uint32_t max_pending;
TALLOC_CTX *ctx;
fr_connection_t *this;
void *conn;
rad_assert(pool != NULL);
/*
* If we have NO connections, and we've previously failed
* opening connections, don't open multiple connections until
* we successfully open at least one.
*/
if ((pool->num == 0) && pool->pending && pool->last_failed) {
return NULL;
}
pthread_mutex_lock(&pool->mutex);
rad_assert(pool->num <= pool->max);
/*
* Don't spawn too many connections at the same time.
*/
if ((pool->num + pool->pending) >= pool->max) {
pthread_mutex_unlock(&pool->mutex);
ERROR("%s: Cannot open new connection, already at max", pool->log_prefix);
return NULL;
}
/*
* If the last attempt failed, wait a bit before
* retrying.
*/
if (pool->last_failed && ((pool->last_failed + pool->retry_delay) > now)) {
bool complain = false;
if (pool->last_throttled != now) {
complain = true;
pool->last_throttled = now;
}
pthread_mutex_unlock(&pool->mutex);
if (!RATE_LIMIT_ENABLED || complain) {
ERROR("%s: Last connection attempt failed, waiting %d seconds before retrying",
pool->log_prefix, pool->retry_delay);
}
return NULL;
}
/*
* We limit the rate of new connections after a failed attempt.
*/
if (pool->pending > pool->max_pending) {
pthread_mutex_unlock(&pool->mutex);
RATE_LIMIT(WARN("%s: Cannot open a new connection due to rate limit after failure",
pool->log_prefix));
return NULL;
}
pool->pending++;
number = pool->count++;
/*
* Unlock the mutex while we try to open a new
* connection. If there are issues with the back-end,
* opening a new connection may take a LONG time. In
* that case, we want the other connections to continue
* to be used.
*/
pthread_mutex_unlock(&pool->mutex);
/*
* The true value for max_pending is the smaller of
* free connection slots, or pool->max_pending.
*/
max_pending = (pool->max - pool->num);
if (pool->max_pending < max_pending) max_pending = pool->max_pending;
INFO("%s: Opening additional connection (%" PRIu64 "), %u of %u pending slots used",
pool->log_prefix, number, pool->pending, max_pending);
/*
* Allocate a new top level ctx for the create callback
* to hang its memory off of.
*/
ctx = talloc_init("fr_connection_ctx");
if (!ctx) return NULL;
/*
* This may take a long time, which prevents other
* threads from releasing connections. We don't care
* about other threads opening new connections, as we
* already have no free connections.
*/
conn = pool->create(ctx, pool->opaque);
if (!conn) {
ERROR("%s: Opening connection failed (%" PRIu64 ")", pool->log_prefix, number);
pool->last_failed = now;
pthread_mutex_lock(&pool->mutex);
pool->max_pending = 1;
pool->pending--;
pthread_mutex_unlock(&pool->mutex);
return NULL;
}
/*
* And lock the mutex again while we link the new
* connection back into the pool.
*/
pthread_mutex_lock(&pool->mutex);
this = talloc_zero(pool, fr_connection_t);
if (!this) {
pthread_mutex_unlock(&pool->mutex);
return NULL;
}
fr_link_talloc_ctx_free(this, ctx);
this->created = now;
this->connection = conn;
this->in_use = in_use;
this->number = number;
this->last_used = now;
fr_connection_link_head(pool, this);
pool->num++;
rad_assert(pool->pending > 0);
pool->pending--;
/*
* We've successfully opened one more connection. Allow
* more connections to open in parallel.
*/
if (pool->max_pending < pool->max) pool->max_pending++;
pool->last_spawned = time(NULL);
pool->delay_interval = pool->cleanup_interval;
pool->next_delay = pool->cleanup_interval;
pool->last_failed = 0;
pthread_mutex_unlock(&pool->mutex);
fr_connection_exec_trigger(pool, "open");
return this;
}
/** Close an existing connection.
*
* Removes the connection from the list, calls the delete callback to close
* the connection, then frees memory allocated to the connection.
*
* @note Will call the 'close' trigger.
* @note Must be called with the mutex held.
*
* @param[in,out] pool to modify.
* @param[in,out] this Connection to delete.
*/
static void fr_connection_close(fr_connection_pool_t *pool,
fr_connection_t *this)
{
/*
* If it's in use, release it.
*/
if (this->in_use) {
#ifdef PTHREAD_DEBUG
pthread_t pthread_id = pthread_self();
rad_assert(pthread_equal(this->pthread_id, pthread_id) != 0);
#endif
this->in_use = false;
rad_assert(pool->active != 0);
pool->active--;
}
fr_connection_exec_trigger(pool, "close");
fr_connection_unlink(pool, this);
rad_assert(pool->num > 0);
pool->num--;
talloc_free(this);
}
/** Find a connection handle in the connection list
*
* Walks over the list of connections searching for a specified connection
* handle and returns the first connection that contains that pointer.
*
* @note Will lock mutex and only release mutex if connection handle
* is not found, so will usually return will mutex held.
* @note Must be called with the mutex free.
*
* @param[in] pool to search in.
* @param[in] conn handle to search for.
* @return the connection containing the specified handle, or NULL if non is
* found.
*/
static fr_connection_t *fr_connection_find(fr_connection_pool_t *pool, void *conn)
{
fr_connection_t *this;
if (!pool || !conn) return NULL;
pthread_mutex_lock(&pool->mutex);
/*
* FIXME: This loop could be avoided if we passed a 'void
* **connection' instead. We could use "offsetof" in
* order to find top of the parent structure.
*/
for (this = pool->head; this != NULL; this = this->next) {
if (this->connection == conn) {
#ifdef PTHREAD_DEBUG
pthread_t pthread_id;
pthread_id = pthread_self();
rad_assert(pthread_equal(this->pthread_id, pthread_id) != 0);
#endif
rad_assert(this->in_use == true);
return this;
}
}
pthread_mutex_unlock(&pool->mutex);
return NULL;
}
/** Delete a connection from the connection pool.
*
* Resolves the connection handle to a connection, then (if found)
* closes, unlinks and frees that connection.
*
* @note Must be called with the mutex free.
*
* @param[in,out] pool Connection pool to modify.
* @param[in] conn to delete.
* @return 0 if the connection could not be found, else 1.
*/
int fr_connection_del(fr_connection_pool_t *pool, void *conn)
{
fr_connection_t *this;
this = fr_connection_find(pool, conn);
if (!this) return 0;
INFO("%s: Deleting connection (%" PRIu64 ")", pool->log_prefix, this->number);
fr_connection_close(pool, this);
fr_connection_pool_check(pool);
return 1;
}
/** Delete a connection pool
*
* Closes, unlinks and frees all connections in the connection pool, then frees
* all memory used by the connection pool.
*
* @note Will call the 'stop' trigger.
* @note Must be called with the mutex free.
*
* @param[in,out] pool to delete.
*/
void fr_connection_pool_delete(fr_connection_pool_t *pool)
{
fr_connection_t *this;
if (!pool) return;
DEBUG("%s: Removing connection pool", pool->log_prefix);
pthread_mutex_lock(&pool->mutex);
/*
* Don't loop over the list. Just keep removing the head
* until they're all gone.
*/
while ((this = pool->head) != NULL) {
INFO("%s: Closing connection (%" PRIu64 ")", pool->log_prefix, this->number);
fr_connection_close(pool, this);
}
fr_connection_exec_trigger(pool, "stop");
rad_assert(pool->head == NULL);
rad_assert(pool->tail == NULL);
rad_assert(pool->num == 0);
talloc_free(pool);
}
/** Initialise a module specific connection pool
*
* @see fr_connection_pool_init
*
* @param[in] module section.
* @param[in] opaque data pointer to pass to callbacks.
* @param[in] c Callback to create new connections.
* @param[in] a Callback to check the status of connections.
* @param[in] log_prefix override, if NULL will be set automatically from the module CONF_SECTION.
* @return A new connection pool or NULL on error.
*/
fr_connection_pool_t *fr_connection_pool_module_init(CONF_SECTION *module,
void *opaque,
fr_connection_create_t c,
fr_connection_alive_t a,
char const *log_prefix)
{
CONF_SECTION *cs, *mycs;
char buff[128];
char trigger_prefix[64];
fr_connection_pool_t *pool;
char const *cs_name1, *cs_name2;
int ret;
#define CONNECTION_POOL_CF_KEY "connection_pool"
#define parent_name(_x) cf_section_name(cf_item_parent(cf_section_to_item(_x)))
cs_name1 = cf_section_name1(module);
cs_name2 = cf_section_name2(module);
if (!cs_name2) cs_name2 = cs_name1;
snprintf(trigger_prefix, sizeof(trigger_prefix), "modules.%s.", cs_name1);
if (!log_prefix) {
snprintf(buff, sizeof(buff), "rlm_%s (%s)", cs_name1, cs_name2);
log_prefix = buff;
}
/*
* Get sibling's pool config section
*/
ret = find_module_sibling_section(&cs, module, "pool");
switch (ret) {
case -1:
return NULL;
case 1:
DEBUG4("%s: Using pool section from \"%s\"", log_prefix, parent_name(cs));
break;
case 0:
DEBUG4("%s: Using local pool section", log_prefix);
break;
}
/*
* Get our pool config section
*/
mycs = cf_section_sub_find(module, "pool");
if (!mycs) {
DEBUG4("%s: Adding pool section to config item \"%s\" to store pool references", log_prefix,
cf_section_name(module));
mycs = cf_section_alloc(module, "pool", NULL);
cf_section_add(module, mycs);
}
/*
* Sibling didn't have a pool config section
* Use our own local pool.
*/
if (!cs) {
DEBUG4("%s: \"%s.pool\" section not found, using \"%s.pool\"", log_prefix,
parent_name(cs), parent_name(mycs));
cs = mycs;
}
/*
* If fr_connection_pool_init has already been called
* for this config section, reuse the previous instance.
*
* This allows modules to pass in the config sections
* they would like to use the connection pool from.
*/
pool = cf_data_find(cs, CONNECTION_POOL_CF_KEY);
if (!pool) {
DEBUG4("%s: No pool reference found for config item \"%s.pool\"", log_prefix, parent_name(cs));
pool = fr_connection_pool_init(module, cs, opaque, c, a, log_prefix, trigger_prefix);
if (!pool) return NULL;
DEBUG4("%s: Adding pool reference %p to config item \"%s.pool\"", log_prefix, pool, parent_name(cs));
cf_data_add(cs, CONNECTION_POOL_CF_KEY, pool, NULL);
return pool;
}
DEBUG4("%s: Found pool reference %p in config item \"%s.pool\"", log_prefix, pool, parent_name(cs));
/*
* We're reusing pool data add it to our local config
* section. This allows other modules to transitively
* re-use a pool through this module.
*/
if (mycs != cs) {
DEBUG4("%s: Copying pool reference %p from config item \"%s.pool\" to config item \"%s.pool\"",
log_prefix, pool, parent_name(cs), parent_name(mycs));
cf_data_add(mycs, CONNECTION_POOL_CF_KEY, pool, NULL);
}
return pool;
}
/** Create a new connection pool
*
* Allocates structures used by the connection pool, initialises the various
* configuration options and counters, and sets the callback functions.
*
* Will also spawn the number of connections specified by the 'start'
* configuration options.
*
* @note Will call the 'start' trigger.
*
* @param[in] parent section.
* @param[in] cs pool section.
* @param[in] opaque data pointer to pass to callbacks.
* @param[in] c Callback to create new connections.
* @param[in] a Callback to check the status of connections.
* @param[in] log_prefix prefix to prepend to all log messages.
* @param[in] trigger_prefix prefix to prepend to all trigger names.
* @return A new connection pool or NULL on error.
*/
fr_connection_pool_t *fr_connection_pool_init(CONF_SECTION *parent,
CONF_SECTION *cs,
void *opaque,
fr_connection_create_t c,
fr_connection_alive_t a,
char const *log_prefix,
char const *trigger_prefix)
{
uint32_t i;
fr_connection_pool_t *pool;
fr_connection_t *this;
time_t now;
if (!parent || !cs || !opaque || !c) return NULL;
now = time(NULL);
/*
* Pool is allocated in the NULL context as
* threads are likely to allocate memory
* beneath the pool.
*/
pool = talloc_zero(NULL, fr_connection_pool_t);
if (!pool) return NULL;
/*
* Ensure the pool is freed at the same time
* as its parent.
*/
if (fr_link_talloc_ctx_free(cs, pool) < 0) {
talloc_free(pool);
return NULL;
}
pool->cs = cs;
pool->opaque = opaque;
pool->create = c;
pool->alive = a;
pool->head = pool->tail = NULL;
pool->log_prefix = log_prefix ? talloc_typed_strdup(pool, log_prefix) : "core";
pool->trigger_prefix = trigger_prefix ?
talloc_typed_strdup(pool, trigger_prefix) : "";
#ifdef HAVE_PTHREAD_H
pthread_mutex_init(&pool->mutex, NULL);
#endif
DEBUG("%s: Initialising connection pool", pool->log_prefix);
if (cf_section_parse(cs, pool, connection_config) < 0) goto error;
/*
* Some simple limits
*/
if (pool->max == 0) {
cf_log_err_cs(cs, "Cannot set 'max' to zero");
goto error;
}
pool->max_pending = pool->max; /* can open all connections now */
if (pool->min > pool->max) {
cf_log_err_cs(cs, "Cannot set 'min' to more than 'max'");
goto error;
}
FR_INTEGER_BOUND_CHECK("max", pool->max, <=, 1024);
FR_INTEGER_BOUND_CHECK("start", pool->start, <=, pool->max);
FR_INTEGER_BOUND_CHECK("spare", pool->spare, <=, (pool->max - pool->min));
if (pool->lifetime > 0) {
FR_INTEGER_COND_CHECK("idle_timeout", pool->idle_timeout, (pool->idle_timeout <= pool->lifetime), 0);
}
if (pool->idle_timeout > 0) {
FR_INTEGER_BOUND_CHECK("cleanup_interval", pool->cleanup_interval, <=, pool->idle_timeout);
}
/*
* Don't open any connections. Instead, force the limits
* to only 1 connection.
*
*/
if (check_config) {
pool->start = pool->min = pool->max = 1;
return pool;
}
/*
* Create all of the connections, unless the admin says
* not to.
*/
for (i = 0; i < pool->start; i++) {
this = fr_connection_spawn(pool, now, false);
if (!this) {
error:
fr_connection_pool_delete(pool);
return NULL;
}
}
fr_connection_exec_trigger(pool, "start");
return pool;
}
/** Check whether a connection needs to be removed from the pool
*
* Will verify that the connection is within idle_timeout, max_uses, and
* lifetime values. If it is not, the connection will be closed.
*
* @note Will only close connections not in use.
* @note Must be called with the mutex held.
*
* @param[in,out] pool to modify.
* @param[in,out] this Connection to manage.
* @param[in] now Current time.
* @return 0 if the connection was closed, otherwise 1.
*/
static int fr_connection_manage(fr_connection_pool_t *pool,
fr_connection_t *this,
time_t now)
{
rad_assert(pool != NULL);
rad_assert(this != NULL);
/*
* Don't terminated in-use connections
*/
if (this->in_use) return 1;
if ((pool->max_uses > 0) &&
(this->num_uses >= pool->max_uses)) {
DEBUG("%s: Closing expired connection (%" PRIu64 "): Hit max_uses limit", pool->log_prefix,
this->number);
do_delete:
if (pool->num <= pool->min) {
RATE_LIMIT(WARN("%s: You probably need to lower \"min\"", pool->log_prefix));
}
fr_connection_close(pool, this);
return 0;
}
if ((pool->lifetime > 0) &&
((this->created + pool->lifetime) < now)) {
DEBUG("%s: Closing expired connection (%" PRIu64 "): Hit lifetime limit",
pool->log_prefix, this->number);
goto do_delete;
}
if ((pool->idle_timeout > 0) &&
((this->last_used + pool->idle_timeout) < now)) {
INFO("%s: Closing connection (%" PRIu64 "): Hit idle_timeout, was idle for %u seconds",
pool->log_prefix, this->number, (int) (now - this->last_used));
goto do_delete;
}
return 1;
}
/** Check whether any connections need to be removed from the pool
*
* Maintains the number of connections in the pool as per the configuration
* parameters for the connection pool.
*
* @note Will only run checks the first time it's called in a given second,
* to throttle connection spawning/closing.
* @note Will only close connections not in use.
* @note Must be called with the mutex held, will release mutex before
* returning.
*
* @param[in,out] pool to manage.
* @return 1
*/
static int fr_connection_pool_check(fr_connection_pool_t *pool)
{
uint32_t spawn, idle, extra;
time_t now = time(NULL);
fr_connection_t *this, *next;
if (pool->last_checked == now) {
pthread_mutex_unlock(&pool->mutex);
return 1;
}
/*
* Some idle connections are OK, if they're within the
* configured "spare" range. Any extra connections
* outside of that range can be closed.
*/
idle = pool->num - pool->active;
if (idle <= pool->spare) {
extra = 0;
} else {
extra = idle - pool->spare;
}
/*
* The other end can close connections. If so, we'll
* have fewer than "min". When that happens, open more
* connections to enforce "min".
*/
if ((pool->num + pool->pending) <= pool->min) {
spawn = pool->min - (pool->num + pool->pending);
extra = 0;
/*
* If we're about to create more than "max",
* don't create more.
*/
} else if ((pool->num + pool->pending) >= pool->max) {
/*
* Ensure we don't spawn more connections. If
* there are extra idle connections, we can
* delete all of them.
*/
spawn = 0;
/* leave extra alone from above */
/*
* min < num < max
*
* AND we don't have enough idle connections.
* Open some more.
*/
} else if (idle <= pool->spare) {
/*
* Not enough spare connections. Spawn a few.
* But cap the pool size at "max"
*/
spawn = pool->spare - idle;
extra = 0;
if ((pool->num + pool->pending + spawn) > pool->max) {
spawn = pool->max - (pool->num + pool->pending);
}
/*
* min < num < max
*
* We have more than enough idle connections, AND
* some are pending. Don't open or close any.
*/
} else if (pool->pending) {
spawn = 0;
extra = 0;
/*
* We have too many idle connections, but closing
* some would take us below "min", so we only
* close enough to take us to "min".
*/
} else if ((pool->min + extra) >= pool->num) {
spawn = 0;
extra = pool->num - pool->min;
} else {
/*
* Closing the "extra" connections won't take us
* below "min". It's therefore safe to close
* them all.
*/
spawn = 0;