res_snmp.c

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/*
 * Copyright (C) 2006 Voop as
 * Thorsten Lockert <tholo@voop.as>
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */
 
/*! \file
 *
 * \brief SNMP Agent / SubAgent support for Asterisk
 *
 * \author Thorsten Lockert <tholo@voop.as>
 *
 * Uses the Net-SNMP libraries available at
 *   http://net-snmp.sourceforge.net/
 */
 
/*! \li \ref res_snmp.c uses the configuration file \ref res_snmp.conf
 * \addtogroup configuration_file Configuration Files
 */
 
/*!
 * \page res_snmp.conf res_snmp.conf
 * \verbinclude res_snmp.conf.sample
 */
 
/*** MODULEINFO
    <depend>netsnmp</depend>
    <support_level>extended</support_level>
 ***/
 
#include "asterisk.h"
 
#include "asterisk/channel.h"
#include "asterisk/module.h"
 
#include "snmp/agent.h"
 
#define MODULE_DESCRIPTION  "SNMP [Sub]Agent for Asterisk"
 
int res_snmp_agentx_subagent;
int res_snmp_dont_stop;
static int res_snmp_enabled;
 
static pthread_t thread = AST_PTHREADT_NULL;
 
/*!
 * \brief Load res_snmp.conf config file
 * \return 1 on load, 0 file does not exist
*/
static int load_config(void)
{
    struct ast_variable *var;
    struct ast_config *cfg;
    struct ast_flags config_flags = { 0 };
    char *cat;
 
    res_snmp_enabled = 0;
    res_snmp_agentx_subagent = 1;
    cfg = ast_config_load("res_snmp.conf", config_flags);
    if (cfg == CONFIG_STATUS_FILEMISSING || cfg == CONFIG_STATUS_FILEINVALID) {
        ast_log(LOG_WARNING, "Could not load res_snmp.conf\n");
        return 0;
    }
    cat = ast_category_browse(cfg, NULL);
    while (cat) {
        var = ast_variable_browse(cfg, cat);
 
        if (strcasecmp(cat, "general") == 0) {
            while (var) {
                if (strcasecmp(var->name, "subagent") == 0) {
                    if (ast_true(var->value))
                        res_snmp_agentx_subagent = 1;
                    else if (ast_false(var->value))
                        res_snmp_agentx_subagent = 0;
                    else {
                        ast_log(LOG_ERROR, "Value '%s' does not evaluate to true or false.\n", var->value);
                        ast_config_destroy(cfg);
                        return 1;
                    }
                } else if (strcasecmp(var->name, "enabled") == 0) {
                    res_snmp_enabled = ast_true(var->value);
                } else {
                    ast_log(LOG_ERROR, "Unrecognized variable '%s' in category '%s'\n", var->name, cat);
                    ast_config_destroy(cfg);
                    return 1;
                }
                var = var->next;
            }
        } else {
            ast_log(LOG_ERROR, "Unrecognized category '%s'\n", cat);
            ast_config_destroy(cfg);
            return 1;
        }
 
        cat = ast_category_browse(cfg, cat);
    }
    ast_config_destroy(cfg);
    return 1;
}
 
/*!
 * \brief Load the module
 *
 * Module loading including tests for configuration or dependencies.
 * This function can return AST_MODULE_LOAD_FAILURE, AST_MODULE_LOAD_DECLINE,
 * or AST_MODULE_LOAD_SUCCESS. If a dependency or environment variable fails
 * tests return AST_MODULE_LOAD_FAILURE. If the module can not load the
 * configuration file or other non-critical problem return
 * AST_MODULE_LOAD_DECLINE. On success return AST_MODULE_LOAD_SUCCESS.
 */
static int load_module(void)
{
    if(!load_config())
        return AST_MODULE_LOAD_DECLINE;
 
    ast_verb(1, "Loading [Sub]Agent Module\n");
 
    res_snmp_dont_stop = 1;
    if (res_snmp_enabled)
        return ast_pthread_create_background(&thread, NULL, agent_thread, NULL);
    else
        return 0;
}
 
static int unload_module(void)
{
    ast_verb(1, "Unloading [Sub]Agent Module\n");
 
    res_snmp_dont_stop = 0;
    return ((thread != AST_PTHREADT_NULL) ? pthread_join(thread, NULL) : 0);
}
 
AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_DEFAULT, "SNMP [Sub]Agent for Asterisk",
    .support_level = AST_MODULE_SUPPORT_EXTENDED,
    .load = load_module,
    .unload = unload_module,
);