rlm_cache_memcached.c

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/*
 *   This program is 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
 */
 
/**
 * $Id: b9fb5b8da9f05817f693eb843b0fbf621e446d5b $
 * @file rlm_cache_memcached.c
 * @brief memcached based cache.
 *
 * @copyright 2014 The FreeRADIUS server project
 */
 
#define LOG_PREFIX "cache - memcached"
 
#include <libmemcached/memcached.h>
 
#include <freeradius-devel/server/base.h>
#include <freeradius-devel/server/module_rlm.h>
#include <freeradius-devel/util/debug.h>
#include <freeradius-devel/util/value.h>
 
#include "../../rlm_cache.h"
#include "../../serialize.h"
 
typedef struct {
        memcached_st *handle;
} rlm_cache_memcached_handle_t;
 
typedef struct {
        char const              *options;       //!< Connection options
        fr_pool_t       *pool;
} rlm_cache_memcached_t;
 
static const conf_parser_t driver_config[] = {
        { FR_CONF_OFFSET("options", rlm_cache_memcached_t, options), .dflt = "--SERVER=localhost" },
        CONF_PARSER_TERMINATOR
};
 
/** Free a connection handle
 *
 * @param mandle to free.
 */
static int _mod_conn_free(rlm_cache_memcached_handle_t *mandle)
{
        if (mandle->handle) memcached_free(mandle->handle);
 
        return 0;
}
 
/** Create a new memcached handle
 *
 */
static void *mod_conn_create(TALLOC_CTX *ctx, void *instance, fr_time_delta_t timeout)
{
        rlm_cache_memcached_t           *driver = instance;
        rlm_cache_memcached_handle_t    *mandle;
 
        memcached_st                    *sandle;
        memcached_return_t              ret;
 
        sandle = memcached(driver->options, talloc_array_length(driver->options) -1);
        if (!sandle) {
                ERROR("Failed creating memcached connection");
 
                return NULL;
        }
 
        ret = memcached_behavior_set(sandle, MEMCACHED_BEHAVIOR_CONNECT_TIMEOUT, fr_time_delta_to_msec(timeout));
        if (ret != MEMCACHED_SUCCESS) {
                ERROR("%s: %s", memcached_strerror(sandle, ret), memcached_last_error_message(sandle));
        error:
                memcached_free(sandle);
                return NULL;
        }
 
        ret = memcached_version(sandle);
        if (ret != MEMCACHED_SUCCESS) {
                ERROR("%s: %s", memcached_strerror(sandle, ret), memcached_last_error_message(sandle));
                goto error;
        }
 
        mandle = talloc_zero(ctx, rlm_cache_memcached_handle_t);
        mandle->handle = sandle;
        talloc_set_destructor(mandle, _mod_conn_free);
 
        return mandle;
}
 
/** Create a new rlm_cache_memcached instance
 *
 * @param[in] mctx              Data required for instantiation.
 * @return
 *      - 0 on success.
 *      - -1 on failure.
 */
static int mod_instantiate(module_inst_ctx_t const *mctx)
{
        rlm_cache_memcached_t           *driver = talloc_get_type_abort(mctx->mi->data, rlm_cache_memcached_t);
        CONF_SECTION                    *conf = mctx->mi->conf;
        memcached_return_t              ret;
        char                            buffer[256];
        rlm_cache_config_t const        *config = talloc_get_type_abort(mctx->mi->parent->data, rlm_cache_config_t);
 
        fr_assert(config);
 
        snprintf(buffer, sizeof(buffer), "rlm_cache (%s)", mctx->mi->parent->name);
 
        ret = libmemcached_check_configuration(driver->options, talloc_array_length(driver->options) -1,
                                               buffer, sizeof(buffer));
        if (ret != MEMCACHED_SUCCESS) {
                ERROR("%s", buffer);
                return -1;
        }
 
        driver->pool = module_rlm_connection_pool_init(conf, driver, mod_conn_create, NULL,
                                                   buffer, "modules.rlm_cache.pool", NULL);
        if (!driver->pool) return -1;
 
        talloc_link_ctx(driver, driver->pool);  /* Ensure pool is freed */
 
        if (config->max_entries > 0) {
                ERROR("max_entries is not supported by this driver");
                return -1;
        }
        return 0;
}
 
static int mod_load(void)
{
        INFO("%s", memcached_lib_version());
        return 0;
}
 
/** Locate a cache entry in memcached
 *
 * @copydetails cache_entry_free_t
 */
static void cache_entry_free(rlm_cache_entry_t *c)
{
        talloc_free(c);
}
 
/** Locate a cache entry in memcached
 *
 * @copydetails cache_entry_find_t
 */
static cache_status_t cache_entry_find(rlm_cache_entry_t **out,
                                       UNUSED rlm_cache_config_t const *config, UNUSED void *instance,
                                       request_t *request, void *handle, fr_value_box_t const *key)
{
        rlm_cache_memcached_handle_t *mandle = handle;
 
        memcached_return_t      mret;
        size_t                  len;
        int                     ret;
        uint32_t                flags;
 
        char                    *from_store;
 
        rlm_cache_entry_t       *c;
 
        from_store = memcached_get(mandle->handle, (char const *)key->vb_strvalue, key->vb_length, &len, &flags, &mret);
        if (!from_store) {
                if (mret == MEMCACHED_NOTFOUND) return CACHE_MISS;
 
                RERROR("Failed retrieving entry: %s: %s", memcached_strerror(mandle->handle, mret),
                       memcached_last_error_message(mandle->handle));
 
                return CACHE_ERROR;
        }
        RDEBUG2("Retrieved %zu bytes from memcached", len);
        RDEBUG2("%s", from_store);
 
        MEM(c = talloc_zero(NULL, rlm_cache_entry_t));
        ret = cache_deserialize(c, request->dict, from_store, len);
        free(from_store);
        if (ret < 0) {
                RPERROR("Invalid entry");
        error:
                talloc_free(c);
                return CACHE_ERROR;
        }
        if (unlikely(fr_value_box_copy(c, &c->key, key) < 0)) {
                RERROR("Failed copying key");
                goto error;
        }
 
        *out = c;
 
        return CACHE_OK;
}
 
/** Insert a new entry into the data store
 *
 * @copydetails cache_entry_insert_t
 */
static cache_status_t cache_entry_insert(UNUSED rlm_cache_config_t const *config, UNUSED void *instance,
                                         request_t *request, void *handle, const rlm_cache_entry_t *c)
{
        rlm_cache_memcached_handle_t *mandle = handle;
 
        memcached_return_t ret;
 
        TALLOC_CTX *pool;
        char *to_store;
 
        pool = talloc_pool(NULL, 1024);
        if (!pool) return CACHE_ERROR;
 
        if (cache_serialize(pool, &to_store, c) < 0) {
                talloc_free(pool);
 
                return CACHE_ERROR;
        }
 
        ret = memcached_set(mandle->handle, (char const *)c->key.vb_strvalue, c->key.vb_length,
                            to_store ? to_store : "",
                            to_store ? talloc_array_length(to_store) - 1 : 0, fr_unix_time_to_sec(c->expires), 0);
        talloc_free(pool);
        if (ret != MEMCACHED_SUCCESS) {
                RERROR("Failed storing entry: %s: %s", memcached_strerror(mandle->handle, ret),
                       memcached_last_error_message(mandle->handle));
 
                return CACHE_ERROR;
        }
 
        return CACHE_OK;
}
 
/** Call delete the cache entry from memcached
 *
 * @copydetails cache_entry_expire_t
 */
static cache_status_t cache_entry_expire(UNUSED rlm_cache_config_t const *config, UNUSED void *instance,
                                         request_t *request, void *handle, fr_value_box_t const *key)
{
        rlm_cache_memcached_handle_t *mandle = handle;
 
        memcached_return_t ret;
 
        ret = memcached_delete(mandle->handle, (char const *)key->vb_strvalue, key->vb_length, 0);
        switch (ret) {
        case MEMCACHED_SUCCESS:
                return CACHE_OK;
 
        case MEMCACHED_DATA_DOES_NOT_EXIST:
                return CACHE_MISS;
 
        default:
                RERROR("Failed deleting entry: %s", memcached_last_error_message(mandle->handle));
                return CACHE_ERROR;
        }
}
 
/** Get a memcached handle
 *
 * @copydetails cache_acquire_t
 */
static int mod_conn_get(void **handle, UNUSED rlm_cache_config_t const *config, void *instance,
                        request_t *request)
{
        rlm_cache_memcached_t *driver = instance;
        rlm_cache_handle_t *mandle;
 
        *handle = NULL;
 
        mandle = fr_pool_connection_get(driver->pool, request);
        if (!mandle) {
                *handle = NULL;
                return -1;
        }
        *handle = mandle;
 
        return 0;
}
 
/** Release a memcached handle
 *
 * @copydetails cache_release_t
 */
static void mod_conn_release(UNUSED rlm_cache_config_t const *config, void *instance,
                             request_t *request, rlm_cache_handle_t *handle)
{
        rlm_cache_memcached_t *driver = instance;
 
        fr_pool_connection_release(driver->pool, request, handle);
}
 
/** Reconnect a memcached handle
 *
 * @copydetails cache_reconnect_t
 */
static int mod_conn_reconnect(void **handle, UNUSED rlm_cache_config_t const *config, void *instance,
                              request_t *request)
{
        rlm_cache_memcached_t *driver = instance;
        rlm_cache_handle_t *mandle;
 
        mandle = fr_pool_connection_reconnect(driver->pool, request, *handle);
        if (!mandle) {
                *handle = NULL;
                return -1;
        }
        *handle = mandle;
 
        return 0;
}
 
extern rlm_cache_driver_t rlm_cache_memcached;
rlm_cache_driver_t rlm_cache_memcached = {
        .common = {
                .magic          = MODULE_MAGIC_INIT,
                .name           = "cache_memcached",
                .inst_size      = sizeof(rlm_cache_memcached_t),
                .config         = driver_config,
 
                .onload         = mod_load,
                .instantiate    = mod_instantiate
        },
 
        .free           = cache_entry_free,
 
        .find           = cache_entry_find,
        .insert         = cache_entry_insert,
        .expire         = cache_entry_expire,
 
        .acquire        = mod_conn_get,
        .release        = mod_conn_release,
        .reconnect      = mod_conn_reconnect
};