rlm_sqlcounter.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: e4e75b347d9fe195b8e689f1205986d82395d9d0 $
 * @file rlm_sqlcounter.c
 * @brief Tracks data usage and other counters using SQL.
 *
 * @copyright 2001,2006 The FreeRADIUS server project
 * @copyright 2001 Alan DeKok (aland@freeradius.org)
 */
RCSID("$Id: e4e75b347d9fe195b8e689f1205986d82395d9d0 $")
 
#define LOG_PREFIX "sqlcounter"
 
#include <rlm_sql.h>
#include <freeradius-devel/server/base.h>
#include <freeradius-devel/server/module_rlm.h>
#include <freeradius-devel/util/debug.h>
#include <freeradius-devel/util/dict.h>
#include <freeradius-devel/unlang/function.h>
 
#include <ctype.h>
 
/*
 *      Note: When your counter spans more than 1 period (ie 3 months
 *      or 2 weeks), this module probably does NOT do what you want! It
 *      calculates the range of dates to count across by first calculating
 *      the End of the Current period and then subtracting the number of
 *      periods you specify from that to determine the beginning of the
 *      range.
 *
 *      For example, if you specify a 3 month counter and today is June 15th,
 *      the end of the current period is June 30. Subtracting 3 months from
 *      that gives April 1st. So, the counter will sum radacct entries from
 *      April 1st to June 30. Then, next month, it will sum entries from
 *      May 1st to July 31st.
 *
 *      To fix this behavior, we need to add some way of storing the Next
 *      Reset Time.
 */
 
/*
 *      Define a structure for our module configuration.
 *
 *      These variables do not need to be in a structure, but it's
 *      a lot cleaner to do so, and a pointer to the structure can
 *      be used as the instance handle.
 */
typedef struct {
        tmpl_t  *start_attr;            //!< &control.${.:instance}-Start
        tmpl_t  *end_attr;              //!< &control.${.:instance}-End
 
        tmpl_t  *counter_attr;          //!< Daily-Session-Time.
        tmpl_t  *limit_attr;            //!< Max-Daily-Session.
        tmpl_t  *key;                   //!< User-Name
 
        char const      *sql_name;      //!< Instance of SQL module to use, usually just 'sql'.
        char const      *query;         //!< SQL query to retrieve current session time.
        char const      *reset;         //!< Daily, weekly, monthly, never or user defined.
        bool            auto_extend;    //!< If the remaining allowance is sufficient to reach the next
                                        ///< period allow for that in setting the reply attribute.
        bool            utc;            //!< Use UTC time.
 
        fr_time_t       reset_time;
        fr_time_t       last_reset;
} rlm_sqlcounter_t;
 
static const conf_parser_t module_config[] = {
        { FR_CONF_OFFSET_FLAGS("sql_module_instance", CONF_FLAG_REQUIRED, rlm_sqlcounter_t, sql_name) },
 
 
        { FR_CONF_OFFSET_FLAGS("query", CONF_FLAG_XLAT | CONF_FLAG_REQUIRED, rlm_sqlcounter_t, query) },
        { FR_CONF_OFFSET_FLAGS("reset", CONF_FLAG_REQUIRED, rlm_sqlcounter_t, reset) },
        { FR_CONF_OFFSET_FLAGS("auto_extend", CONF_FLAG_OK_MISSING, rlm_sqlcounter_t, auto_extend) },
        { FR_CONF_OFFSET_FLAGS("utc", CONF_FLAG_OK_MISSING, rlm_sqlcounter_t, utc) },
 
        { FR_CONF_OFFSET_FLAGS("key", CONF_FLAG_NOT_EMPTY, rlm_sqlcounter_t, key), .dflt = "%{%{Stripped-User-Name} || %{User-Name}}", .quote = T_DOUBLE_QUOTED_STRING },
 
        { FR_CONF_OFFSET_FLAGS("reset_period_start_name", CONF_FLAG_ATTRIBUTE, rlm_sqlcounter_t, start_attr),
          .dflt = "&control.${.:instance}-Reset-Start", .quote = T_BARE_WORD },
        { FR_CONF_OFFSET_FLAGS("reset_period_end_name", CONF_FLAG_ATTRIBUTE, rlm_sqlcounter_t, end_attr),
          .dflt = "&control.${.:instance}-Reset-End", .quote = T_BARE_WORD },
 
        /* Attribute to write counter value to*/
        { FR_CONF_OFFSET_FLAGS("counter_name", CONF_FLAG_ATTRIBUTE | CONF_FLAG_REQUIRED, rlm_sqlcounter_t, counter_attr) },
        { FR_CONF_OFFSET_FLAGS("check_name", CONF_FLAG_ATTRIBUTE | CONF_FLAG_REQUIRED, rlm_sqlcounter_t, limit_attr) },
 
        CONF_PARSER_TERMINATOR
};
 
typedef struct {
        xlat_exp_head_t *query_xlat;            //!< Tokenized xlat to run query.
        tmpl_t          *reply_attr;            //!< Attribute to write timeout to.
        tmpl_t          *reply_msg_attr;        //!< Attribute to write reply message to.
} sqlcounter_call_env_t;
 
static fr_dict_t const *dict_freeradius;
 
extern fr_dict_autoload_t rlm_sqlcounter_dict[];
fr_dict_autoload_t rlm_sqlcounter_dict[] = {
        { .out = &dict_freeradius, .proto = "freeradius" },
        { NULL }
};
 
static int find_next_reset(rlm_sqlcounter_t *inst, fr_time_t now)
{
        int             ret = 0;
        size_t          len;
        unsigned int    num = 1;
        char            last = '\0';
        struct tm       *tm, s_tm;
        time_t          time_s = fr_time_to_sec(now);
 
        if (inst->utc) {
                tm = gmtime_r(&time_s, &s_tm);
        } else {
                tm = localtime_r(&time_s, &s_tm);
        }
        tm->tm_sec = tm->tm_min = 0;
 
        fr_assert(inst->reset != NULL);
 
        if (isdigit((uint8_t) inst->reset[0])){
                len = strlen(inst->reset);
                if (len == 0)
                        return -1;
                last = inst->reset[len - 1];
                if (!isalpha((uint8_t) last))
                        last = 'd';
                num = atoi(inst->reset);
                DEBUG3("num=%d, last=%c",num,last);
        }
        if (strcmp(inst->reset, "hourly") == 0 || last == 'h') {
                /*
                 *  Round up to the next nearest hour.
                 */
                tm->tm_hour += num;
                inst->reset_time = fr_time_from_sec(inst->utc ? timegm(tm) : mktime(tm));
        } else if (strcmp(inst->reset, "daily") == 0 || last == 'd') {
                /*
                 *  Round up to the next nearest day.
                 */
                tm->tm_hour = 0;
                tm->tm_mday += num;
                inst->reset_time = fr_time_from_sec(inst->utc ? timegm(tm) : mktime(tm));
        } else if (strcmp(inst->reset, "weekly") == 0 || last == 'w') {
                /*
                 *  Round up to the next nearest week.
                 */
                tm->tm_hour = 0;
                tm->tm_mday += (7 - tm->tm_wday) +(7*(num-1));
                inst->reset_time = fr_time_from_sec(inst->utc ? timegm(tm) : mktime(tm));
        } else if (strcmp(inst->reset, "monthly") == 0 || last == 'm') {
                tm->tm_hour = 0;
                tm->tm_mday = 1;
                tm->tm_mon += num;
                inst->reset_time = fr_time_from_sec(inst->utc ? timegm(tm) : mktime(tm));
        } else if (strcmp(inst->reset, "never") == 0) {
                inst->reset_time = fr_time_wrap(0);
        } else {
                return -1;
        }
 
        DEBUG2("Current Time: %pV, Next reset %pV", fr_box_time(now), fr_box_time(inst->reset_time));
 
        return ret;
}
 
 
/*  I don't believe that this routine handles Daylight Saving Time adjustments
    properly.  Any suggestions?
*/
static int find_prev_reset(rlm_sqlcounter_t *inst, fr_time_t now)
{
        int             ret = 0;
        size_t          len;
        unsigned        int num = 1;
        char            last = '\0';
        struct          tm *tm, s_tm;
        time_t          time_s = fr_time_to_sec(now);
 
        if (inst->utc) {
                tm = gmtime_r(&time_s, &s_tm);
        } else {
                tm = localtime_r(&time_s, &s_tm);
        }
        tm->tm_sec = tm->tm_min = 0;
 
        fr_assert(inst->reset != NULL);
 
        if (isdigit((uint8_t) inst->reset[0])){
                len = strlen(inst->reset);
                if (len == 0)
                        return -1;
                last = inst->reset[len - 1];
                if (!isalpha((uint8_t) last))
                        last = 'd';
                num = atoi(inst->reset);
                DEBUG3("num=%d, last=%c", num, last);
        }
        if (strcmp(inst->reset, "hourly") == 0 || last == 'h') {
                /*
                 *  Round down to the prev nearest hour.
                 */
                tm->tm_hour -= num - 1;
                inst->last_reset = fr_time_from_sec(inst->utc ? timegm(tm) : mktime(tm));
        } else if (strcmp(inst->reset, "daily") == 0 || last == 'd') {
                /*
                 *  Round down to the prev nearest day.
                 */
                tm->tm_hour = 0;
                tm->tm_mday -= num - 1;
                inst->last_reset = fr_time_from_sec(inst->utc ? timegm(tm) : mktime(tm));
        } else if (strcmp(inst->reset, "weekly") == 0 || last == 'w') {
                /*
                 *  Round down to the prev nearest week.
                 */
                tm->tm_hour = 0;
                tm->tm_mday -= tm->tm_wday +(7*(num-1));
                inst->last_reset = fr_time_from_sec(inst->utc ? timegm(tm) : mktime(tm));
        } else if (strcmp(inst->reset, "monthly") == 0 || last == 'm') {
                tm->tm_hour = 0;
                tm->tm_mday = 1;
                tm->tm_mon -= num - 1;
                inst->last_reset = fr_time_from_sec(inst->utc ? timegm(tm) : mktime(tm));
        } else if (strcmp(inst->reset, "never") == 0) {
                inst->reset_time = fr_time_wrap(0);
        } else {
                return -1;
        }
 
        DEBUG2("Current Time: %pV, Prev reset %pV", fr_box_time(now), fr_box_time(inst->last_reset));
 
        return ret;
}
 
typedef struct {
        bool                    last_success;
        fr_value_box_list_t     result;
        rlm_sqlcounter_t        *inst;
        sqlcounter_call_env_t   *env;
        fr_pair_t               *limit;
} sqlcounter_rctx_t;
 
/** Handle the result of calling the SQL query to retrieve the `counter` value.
 *
 * Create / update the `counter` attribute in the control list
 * If `counter` > `limit`, optionally populate a reply message and return RLM_MODULE_REJECT.
 * Otherwise, optionally populate a reply attribute with the value of `limit` - `counter` and return RLM_MODULE_UPDATED.
 * If no reply attribute is set, return RLM_MODULE_OK.
 */
static unlang_action_t mod_authorize_resume(rlm_rcode_t *p_result, UNUSED int *priority, request_t *request, void *uctx)
{
        sqlcounter_rctx_t       *rctx = talloc_get_type_abort(uctx, sqlcounter_rctx_t);
        rlm_sqlcounter_t        *inst = rctx->inst;
        sqlcounter_call_env_t   *env = rctx->env;
        fr_value_box_t          *sql_result = fr_value_box_list_pop_head(&rctx->result);
        uint64_t                counter, res;
        fr_pair_t               *vp, *limit = rctx->limit;
        int                     ret;
        char                    msg[128];
 
        if (!sql_result || (sscanf(sql_result->vb_strvalue, "%" PRIu64, &counter) != 1)) {
                RDEBUG2("No integer found in result string \"%pV\".  May be first session, setting counter to 0",
                        sql_result);
                counter = 0;
        }
 
        /*
         *      Add the counter to the control list
         */
        MEM(pair_update_control(&vp, tmpl_attr_tail_da(inst->counter_attr)) >= 0);
        vp->vp_uint64 = counter;
 
        /*
         *      Check if check item > counter
         */
        if (limit->vp_uint64 <= counter) {
                if (env->reply_msg_attr) {
                        /* User is denied access, send back a reply message */
                        snprintf(msg, sizeof(msg), "Your maximum %s usage has been reached", inst->reset);
 
                        MEM(pair_update_reply(&vp, tmpl_attr_tail_da(env->reply_msg_attr)) >= 0);
                        fr_pair_value_strdup(vp, msg, false);
                }
 
                REDEBUG2("Maximum %s usage reached", inst->reset);
                REDEBUG2("Rejecting user, %s value (%" PRIu64 ") is less than counter value (%" PRIu64 ")",
                         inst->limit_attr->name, limit->vp_uint64, counter);
 
                RETURN_MODULE_REJECT;
        }
 
        res = limit->vp_uint64 - counter;
        RDEBUG2("Allowing user, %s value (%" PRIu64 ") is greater than counter value (%" PRIu64 ")",
                inst->limit_attr->name, limit->vp_uint64, counter);
 
        /*
         *      We are assuming that simultaneous-use=1. But
         *      even if that does not happen then our user
         *      could login at max for 2*max-usage-time Is
         *      that acceptable?
         */
        if (env->reply_attr) {
                fr_value_box_t  vb;
 
                /*
                 *      If we are near a reset then add the next
                 *      limit, so that the user will not need to login
                 *      again.  Do this only if auto_extend is set.
                 */
                if (inst->auto_extend &&
                    fr_time_gt(inst->reset_time, fr_time_wrap(0)) &&
                    ((int64_t)res >= fr_time_delta_to_sec(fr_time_sub(inst->reset_time, request->packet->timestamp)))) {
                        fr_time_delta_t to_reset = fr_time_sub(inst->reset_time, request->packet->timestamp);
 
                        RDEBUG2("Time remaining (%pV) is greater than time to reset (%" PRIu64 "s).  "
                                "Adding %pV to reply value",
                                fr_box_time_delta(to_reset), res, fr_box_time_delta(to_reset));
                        res = fr_time_delta_to_sec(to_reset) + limit->vp_uint64;
                }
 
                fr_value_box_init(&vb, FR_TYPE_UINT64, NULL, false);
                vb.vb_uint64 = res;
 
                /*
                 *      Limit the reply attribute to the minimum of the existing value, or this new one.
                 */
                ret = tmpl_find_or_add_vp(&vp, request, env->reply_attr);
                switch (ret) {
                case 1:         /* new */
                        break;
 
                case 0:         /* found */
                {
                        fr_value_box_t  existing;
                        fr_value_box_cast(NULL, &existing, FR_TYPE_UINT64, NULL, &vp->data);
                        if (fr_value_box_cmp(&vb, &existing) == 1) {
                                RDEBUG2("Leaving existing %s value of %pV" , env->reply_attr->name,
                                        &vp->data);
                                RETURN_MODULE_OK;
                        }
                }
                        break;
 
                case -1:        /* alloc failed */
                        REDEBUG("Error allocating attribute %s", env->reply_attr->name);
                        RETURN_MODULE_FAIL;
 
                default:        /* request or list unavailable */
                        RDEBUG2("List or request context not available for %s, skipping...", env->reply_attr->name);
                        RETURN_MODULE_OK;
                }
 
                fr_value_box_cast(vp, &vp->data, vp->data.type, NULL, &vb);
 
                RDEBUG2("%pP", vp);
 
                RETURN_MODULE_UPDATED;
        }
 
        RETURN_MODULE_OK;
}
 
/** Check the value of a `counter` retrieved from an SQL query with a `limit`
 *
 * Module specific attributes containing the start / end times are created / updated,
 * the query is tokenized as an xlat call to the relevant SQL module and then
 * pushed on the stack for evaluation.
 */
static unlang_action_t CC_HINT(nonnull) mod_authorize(rlm_rcode_t *p_result, module_ctx_t const *mctx, request_t *request)
{
        rlm_sqlcounter_t        *inst = talloc_get_type_abort(mctx->mi->data, rlm_sqlcounter_t);
        sqlcounter_call_env_t   *env = talloc_get_type_abort(mctx->env_data, sqlcounter_call_env_t);
        fr_pair_t               *limit, *vp;
        sqlcounter_rctx_t       *rctx;
 
        /*
         *      Before doing anything else, see if we have to reset
         *      the counters.
         */
        if (fr_time_neq(inst->reset_time, fr_time_wrap(0)) &&
            (fr_time_lteq(inst->reset_time, request->packet->timestamp))) {
                /*
                 *      Re-set the next time and prev_time for this counters range
                 */
                inst->last_reset = inst->reset_time;
                find_next_reset(inst, request->packet->timestamp);
        }
 
        if (tmpl_find_vp(&limit, request, inst->limit_attr) < 0) {
                RWDEBUG2("Couldn't find %s, doing nothing...", inst->limit_attr->name);
                RETURN_MODULE_NOOP;
        }
 
        /*
         *      Populate start and end attributes for use in query expansion
         */
        if (tmpl_find_or_add_vp(&vp, request, inst->start_attr) < 0) {
                REDEBUG("Couldn't create %s", inst->start_attr->name);
                RETURN_MODULE_FAIL;
        }
        vp->vp_uint64 = fr_time_to_sec(inst->last_reset);
 
        if (tmpl_find_or_add_vp(&vp, request, inst->end_attr) < 0) {
                REDEBUG2("Couldn't create %s", inst->end_attr->name);
                RETURN_MODULE_FAIL;
        }
        vp->vp_uint64 = fr_time_to_sec(inst->reset_time);
 
        MEM(rctx = talloc(unlang_interpret_frame_talloc_ctx(request), sqlcounter_rctx_t));
        *rctx = (sqlcounter_rctx_t) {
                .inst = inst,
                .env = env,
                .limit = limit
        };
 
        if (unlang_function_push(request, NULL, mod_authorize_resume, NULL, 0, UNLANG_SUB_FRAME, rctx) < 0) {
        error:
                talloc_free(rctx);
                RETURN_MODULE_FAIL;
        }
 
        fr_value_box_list_init(&rctx->result);
        if (unlang_xlat_push(rctx, &rctx->last_success, &rctx->result, request, env->query_xlat, UNLANG_SUB_FRAME) < 0) goto error;
 
        return UNLANG_ACTION_PUSHED_CHILD;
}
 
/** Custom call_env parser to tokenize the SQL query xlat used for counter retrieval
 */
static int call_env_query_parse(TALLOC_CTX *ctx, void *out, tmpl_rules_t const *t_rules, CONF_ITEM *ci,
                                call_env_ctx_t const *cec, UNUSED call_env_parser_t const *rule)
{
        rlm_sqlcounter_t const  *inst = talloc_get_type_abort_const(cec->mi->data, rlm_sqlcounter_t);
        CONF_PAIR const         *to_parse = cf_item_to_pair(ci);
        char                    *query;
        xlat_exp_head_t         *ex;
 
        query = talloc_asprintf(NULL, "%%%s(\"%s\")", inst->sql_name, cf_pair_value(to_parse));
 
        if (xlat_tokenize(ctx, &ex,
                  &FR_SBUFF_IN(query, talloc_array_length(query)),
                  &(fr_sbuff_parse_rules_t){
                        .escapes = &(fr_sbuff_unescape_rules_t) {
                                .name = "xlat",
                                .chr = '\\',
                                .subs = {
                                        ['%'] = '%',
                                        ['\\'] = '\\',
                                },
                  }}, t_rules, 0) < 0) {
                talloc_free(query);
                return -1;
        }
        talloc_free(query);
 
        if (xlat_needs_resolving(ex) &&
            (xlat_resolve(ex, &(xlat_res_rules_t){ .allow_unresolved = false }) < 0)) {
                talloc_free(ex);
                return -1;
        }
 
        *(void**)out = ex;
        return 0;
}
 
static const call_env_method_t sqlcounter_call_env = {
        FR_CALL_ENV_METHOD_OUT(sqlcounter_call_env_t),
        .env = (call_env_parser_t[]){
                { FR_CALL_ENV_PARSE_ONLY_OFFSET("query", FR_TYPE_VOID, CALL_ENV_FLAG_REQUIRED | CALL_ENV_FLAG_PARSE_ONLY, sqlcounter_call_env_t, query_xlat),
                  .pair.func = call_env_query_parse },
                { FR_CALL_ENV_PARSE_ONLY_OFFSET("reply_name", FR_TYPE_VOID, CALL_ENV_FLAG_PARSE_ONLY, sqlcounter_call_env_t, reply_attr) },
                { FR_CALL_ENV_PARSE_ONLY_OFFSET("reply_message_name", FR_TYPE_VOID, CALL_ENV_FLAG_PARSE_ONLY, sqlcounter_call_env_t, reply_msg_attr) },
                CALL_ENV_TERMINATOR
        }
};
 
 
/*
 *      Do any per-module initialization that is separate to each
 *      configured instance of the module.  e.g. set up connections
 *      to external databases, read configuration files, set up
 *      dictionary entries, etc.
 *
 *      If configuration information is given in the config section
 *      that must be referenced in later calls, store a handle to it
 *      in *instance otherwise put a null pointer there.
 */
static int mod_instantiate(module_inst_ctx_t const *mctx)
{
        rlm_sqlcounter_t        *inst = talloc_get_type_abort(mctx->mi->data, rlm_sqlcounter_t);
        CONF_SECTION            *conf = mctx->mi->conf;
        module_instance_t const *sql_inst;
        fr_assert(inst->query && *inst->query);
 
        sql_inst = module_rlm_static_by_name(NULL, inst->sql_name);
        if (!sql_inst) {
                cf_log_err(conf, "Module \"%s\" not found", inst->sql_name);
                return -1;
        }
 
        if (!talloc_get_type(sql_inst->data, rlm_sql_t)) {
                cf_log_err(conf, "\"%s\" is not an instance of rlm_sql", inst->sql_name);
                return -1;
        }
 
        inst->reset_time = fr_time_wrap(0);
 
        if (find_next_reset(inst, fr_time()) == -1) {
                cf_log_err(conf, "Invalid reset '%s'", inst->reset);
                return -1;
        }
 
        /*
         *  Discover the beginning of the current time period.
         */
        inst->last_reset = fr_time_wrap(0);
 
        if (find_prev_reset(inst, fr_time()) < 0) {
                cf_log_err(conf, "Invalid reset '%s'", inst->reset);
                return -1;
        }
 
        return 0;
}
 
static inline int attr_check(CONF_SECTION *conf, tmpl_t *tmpl, char const *name, fr_dict_attr_flags_t *flags)
{
        if (tmpl_is_attr_unresolved(tmpl) && !fr_dict_attr_by_name(NULL, fr_dict_root(dict_freeradius), tmpl_attr_tail_unresolved(tmpl))) {
                if (fr_dict_attr_add_name_only(fr_dict_unconst(dict_freeradius), fr_dict_root(dict_freeradius),
                                               tmpl_attr_tail_unresolved(tmpl), FR_TYPE_UINT64, flags) < 0) {
                        cf_log_perr(conf, "Failed defining %s attribute", name);
                        return -1;
                }
        } else if (tmpl_is_attr(tmpl)) {
                if (tmpl_attr_tail_da(tmpl)->type != FR_TYPE_UINT64) {
                        cf_log_err(conf, "%s attribute %s must be uint64", name, tmpl_attr_tail_da(tmpl)->name);
                        return -1;
                }
        }
 
        return 0;
}
 
static int mod_bootstrap(module_inst_ctx_t const *mctx)
{
        rlm_sqlcounter_t const  *inst = talloc_get_type_abort(mctx->mi->data, rlm_sqlcounter_t);
        CONF_SECTION            *conf = mctx->mi->conf;
        fr_dict_attr_flags_t    flags = { .internal = 1, .length = 8, .name_only = 1 };
 
        if (unlikely(attr_check(conf, inst->start_attr, "reset_period_start", &flags) < 0)) return -1;
        if (unlikely(attr_check(conf, inst->end_attr, "reset_period_end", &flags) < 0)) return -1;
        if (unlikely(attr_check(conf, inst->counter_attr, "counter", &flags) < 0)) return -1;
        if (unlikely(attr_check(conf, inst->limit_attr, "check", &flags) < 0)) return -1;
 
        return 0;
}
 
/*
 *      The module name should be the only globally exported symbol.
 *      That is, everything else should be 'static'.
 *
 *      If the module needs to temporarily modify it's instantiation
 *      data, the type should be changed to MODULE_TYPE_THREAD_UNSAFE.
 *      The server will then take care of ensuring that the module
 *      is single-threaded.
 */
extern module_rlm_t rlm_sqlcounter;
module_rlm_t rlm_sqlcounter = {
        .common = {
                .magic          = MODULE_MAGIC_INIT,
                .name           = "sqlcounter",
                .inst_size      = sizeof(rlm_sqlcounter_t),
                .config         = module_config,
                .bootstrap      = mod_bootstrap,
                .instantiate    = mod_instantiate,
        },
        .method_group = {
                .bindings = (module_method_binding_t[]){
                        { .section = SECTION_NAME(CF_IDENT_ANY, CF_IDENT_ANY), .method = mod_authorize, .method_env = &sqlcounter_call_env },
                        MODULE_BINDING_TERMINATOR
                }
        }
};