res_snmp.c

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/*
 * Copyright (C) 2006 Voop as
 * Thorsten Lockert <[email protected]>
 *
 * 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 <[email protected]>
 *
 * 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,
);