sub_agent.c

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/*
 * $Id$
 *
 * SNMPStats Module 
 * Copyright (C) 2006 SOMA Networks, INC.
 * Written by: Jeffrey Magder (jmagder@somanetworks.com)
 *
 * This file is part of Kamailio, a free SIP server.
 *
 * Kamailio 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
 *
 * Kamailio 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA
 *
 * History:
 * --------
 * 2006-11-23 initial version (jmagder)
 */

#include <sys/types.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>

#include "sub_agent.h"

/* Bring in the NetSNMP headers */
#include <net-snmp/net-snmp-config.h>
#include <net-snmp/net-snmp-includes.h>
#include <net-snmp/agent/net-snmp-agent-includes.h>

/* Bring in the initialization functions for all scalars */
#include "snmpSIPCommonObjects.h"
#include "snmpSIPServerObjects.h"
#include "snmpObjects.h"

/* Bring in the initialization functions for all tables */
#include "snmpSIPPortTable.h"
#include "snmpSIPMethodSupportedTable.h"
#include "snmpSIPStatusCodesTable.h"
#include "snmpSIPRegUserTable.h"
#include "snmpSIPContactTable.h"
#include "snmpSIPRegUserLookupTable.h"
#include "snmpMIBNotifications.h"

#include "../../dprint.h"
#include "../../cfg/cfg_struct.h"

static int keep_running;

static void sigterm_handler(int signal) 
{
        /* Just exit.  The master agent will clean everything up for us */
        exit(0);
}

static int initialize_agentx(void) 
{
        /* We register with a master agent */
        register_with_master_agent(AGENT_PROCESS_NAME);
        
        /* Initialize all scalars, and let the master agent know we want to
         * handle all OID's pertaining to these scalars. */
        init_openserSIPCommonObjects();
        init_openserSIPServerObjects();
        init_openserObjects();

        /* Initialiaze all the tables, and let the master agent know we want to
         * handle all the OID's pertaining to these tables */
        init_openserSIPPortTable();
        init_openserSIPMethodSupportedTable();
        init_openserSIPStatusCodesTable();
        init_openserSIPRegUserTable();
        init_openserSIPContactTable();
        init_openserSIPRegUserLookupTable();

        /* In case we recevie a request to stop (kill -TERM or kill -INT) */
        keep_running = 1;

        while(keep_running) {
                /* update the local config framework structures */
                cfg_update();

                agent_check_and_process(1); /* 0 == don't block */
        }

        snmp_shutdown(AGENT_PROCESS_NAME);
        SOCK_CLEANUP;
        exit (0);

        return 0;
}

void agentx_child(int rank)
{
        struct sigaction new_sigterm_handler;
        struct sigaction default_handlers;
        struct sigaction sigpipe_handler;

        /* Setup a SIGTERM handler */
        sigfillset(&new_sigterm_handler.sa_mask);
        new_sigterm_handler.sa_flags   = 0;
        new_sigterm_handler.sa_handler = sigterm_handler;
        sigaction(SIGTERM, &new_sigterm_handler, NULL);

        /* We don't want OpenSER's normal handlers doing anything when
         * we die.  As far as OpenSER knows this process never existed.
         * So override all signal handlers to the OS default. */
        sigemptyset(&default_handlers.sa_mask);
        default_handlers.sa_flags = 0;
        default_handlers.sa_handler = SIG_DFL;

        sigaction(SIGCHLD, &default_handlers, NULL);
        sigaction(SIGINT,  &default_handlers, NULL);
        sigaction(SIGHUP,  &default_handlers, NULL);
        sigaction(SIGUSR1, &default_handlers, NULL);
        sigaction(SIGUSR2, &default_handlers, NULL);

        /* It is possible that the master agent will unregister us if we
         * take too long to respond to an SNMP request.  This would
         * happen if a large number of users/contacts have been
         * registered between snmp requests to the user/contact tables.
         * In this situation we may try to write to a closed socket when
         * we are done processing, resulting in a SIGPIPE.  This doesn't
         * need to be fatal however, because we can re-establish our
         * connection.  Therefore we set ourselves up to ignore the
         * SIGPIPE. */
        sigpipe_handler.sa_flags = SA_RESTART;
        sigpipe_handler.sa_handler = SIG_IGN;

        sigaction(SIGPIPE, &sigpipe_handler, NULL);

        initialize_agentx();
}



void register_with_master_agent(char *name_to_register_under) 
{
        /* Set ourselves up as an AgentX Client. */
        netsnmp_ds_set_boolean(NETSNMP_DS_APPLICATION_ID, NETSNMP_DS_AGENT_ROLE, 1);

        /* Initialize TCP if necessary.  (Its here for WIN32) compatibility. */
        SOCK_STARTUP;

        /* Read in our configuration file to determine master agent ping times
         * what port communication is to take place over, etc. */
        init_agent("snmpstats");

        /* Use a name we can register our agent under. */
        init_snmp(name_to_register_under);
}