/*      $OpenBSD: trap.c,v 1.45 2025/12/24 13:36:38 martijn Exp $       */

/*
 * Copyright (c) 2008 Reyk Floeter <reyk@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/queue.h>
#include <sys/socket.h>

#include <ber.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#include "application.h"
#include "log.h"
#include "mib.h"
#include "snmp.h"
#include "snmpd.h"

void
trap_init(void)
{
        /*
         * Send a coldStart to notify that the daemon has been
         * started and re-initialized.
         */
        trap_send(&OID(MIB_coldStart), NULL);
}

int
trap_send(struct ber_oid *oid, struct ber_element *elm)
{
        struct trap_address     *tr;
        struct ber_element      *vblist, *trap;
        struct                   ber_oid uptime = OID(MIB_sysUpTime, 0);
        struct                   ber_oid trapoid = OID(MIB_snmpTrapOID, 0);
        char                     ostr[SNMP_MAX_OID_STRLEN];
        struct snmp_message     *msg;
        int                      r;

        if (TAILQ_EMPTY(&snmpd_env->sc_trapreceivers))
                return (0);

        mib_oid2string(oid, ostr, sizeof(ostr), snmpd_env->sc_oidfmt);
        log_debug("trap_send: oid %s", ostr);

        /* Add mandatory varbind elements */
        trap = ober_add_sequence(NULL);
        vblist = ober_printf_elements(trap, "{Odt}{OO}",
            &uptime, appl_sysuptime(NULL),
            BER_CLASS_APPLICATION, SNMP_T_TIMETICKS,
            &trapoid, oid);
        if (elm != NULL)
                ober_link_elements(vblist, elm);

        TAILQ_FOREACH(tr, &snmpd_env->sc_trapreceivers, entry) {
                if (tr->ta_oid.bo_n) {
                        /* The trap receiver may want only a specified MIB */
                        r = ober_oid_cmp(oid, &tr->ta_oid);
                        if (r != 0 && r != 2)
                                continue;
                }

                if ((msg = calloc(1, sizeof(*msg))) == NULL)
                        fatal("malloc");
                msg->sm_sock = snmpd_socket_af(&tr->ta_ss, SOCK_DGRAM);
                if (msg->sm_sock == -1) {
                        log_warn("socket");
                        free(msg);
                        continue;
                }
                memcpy(&(msg->sm_ss), &(tr->ta_ss), sizeof(msg->sm_ss));
                msg->sm_slen = tr->ta_ss.ss_len;
                if (tr->ta_sslocal.ss_family != 0) {
                        memcpy(&(msg->sm_local_ss), &(tr->ta_sslocal),
                            sizeof(msg->sm_local_ss));
                        msg->sm_local_slen = tr->ta_sslocal.ss_len;
                }
                msg->sm_version = tr->ta_version;
                msg->sm_pdutype = SNMP_C_TRAPV2;
                ober_set_application(&msg->sm_ber, smi_application);
                msg->sm_request = arc4random();
                if ((msg->sm_varbindresp = ober_dup(trap->be_sub)) == NULL)
                        fatal("malloc");

                switch (msg->sm_version) {
                case SNMP_V2:
                        (void)strlcpy(msg->sm_community, tr->ta_community,
                            sizeof(msg->sm_community));
                        break;
                case SNMP_V3:
                        msg->sm_msgid = msg->sm_request & INT32_MAX;
                        msg->sm_max_msg_size = READ_BUF_SIZE;
                        msg->sm_flags = tr->ta_seclevel != -1 ?
                            tr->ta_seclevel : snmpd_env->sc_min_seclevel;
                        msg->sm_secmodel = SNMP_SEC_USM;
                        msg->sm_engine_time = snmpd_engine_time();
                        msg->sm_engine_boots = snmpd_env->sc_engine_boots;
                        msg->sm_ctxengineid = snmpd_env->sc_engineid;
                        (void)strlcpy(msg->sm_username, tr->ta_usmusername,
                            sizeof(msg->sm_username));
                        msg->sm_user = tr->ta_usmuser;
                        arc4random_buf(msg->sm_salt, sizeof(msg->sm_salt));
                        break;
                }

                snmpe_response(msg);
        }
        ober_free_elements(trap);

        return 0;
}