/*      $OpenBSD: application_internal.c,v 1.14 2025/12/24 13:36:38 martijn Exp $       */

/*
 * Copyright (c) 2023 Martijn van Duren <martijn@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/tree.h>
#include <sys/types.h>

#include <stddef.h>

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

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

struct appl_internal_object {
        struct ber_oid                   oid;
        struct ber_element *            (*get)(struct ber_oid *);
        /* No getnext means the object is scalar */
        struct ber_element *            (*getnext)(int8_t, struct ber_oid *);

        int32_t                          intval;
        char                            *stringval;

        RB_ENTRY(appl_internal_object)   entry;
};

void appl_internal_region(struct ber_oid *);
void appl_internal_object(struct ber_oid *,
    struct ber_element *(*)(struct ber_oid *),
    struct ber_element *(*)(int8_t, struct ber_oid *));
void appl_internal_get(struct appl_backend *, int32_t, int32_t, const char *,
    struct appl_varbind *);
void appl_internal_getnext(struct appl_backend *, int32_t, int32_t,
    const char *, struct appl_varbind *);
struct ber_element *appl_internal_snmp(struct ber_oid *);
struct ber_element *appl_internal_engine(struct ber_oid *);
struct ber_element *appl_internal_usmstats(struct ber_oid *);
struct ber_element *appl_internal_system(struct ber_oid *);
struct ber_element *appl_internal_get_int(struct ber_oid *);
struct ber_element *appl_internal_get_string(struct ber_oid *);
struct appl_internal_object *appl_internal_object_parent(struct ber_oid *);
int appl_internal_object_cmp(struct appl_internal_object *,
    struct appl_internal_object *);

struct appl_backend_functions appl_internal_functions = {
        .ab_get = appl_internal_get,
        .ab_getnext = appl_internal_getnext,
        .ab_getbulk = NULL, /* getbulk is too complex */
};

struct appl_backend appl_internal = {
        .ab_name = "internal",
        .ab_cookie = NULL,
        .ab_retries = 0,
        .ab_range = 1,
        .ab_fn = &appl_internal_functions
};

struct appl_backend appl_config = {
        .ab_name = "config",
        .ab_cookie = NULL,
        .ab_retries = 0,
        .ab_range = 1,
        .ab_fn = &appl_internal_functions
};

static RB_HEAD(appl_internal_objects, appl_internal_object)
    appl_internal_objects = RB_INITIALIZER(&appl_internal_objects),
    appl_internal_objects_conf = RB_INITIALIZER(&appl_internal_objects_conf);
RB_PROTOTYPE_STATIC(appl_internal_objects, appl_internal_object, entry,
    appl_internal_object_cmp);

void
appl_internal_init(void)
{
        struct appl_internal_object *obj;
        struct ber_oid oid;

        appl_internal_region(&OID(MIB_system));
        appl_internal_object(&OID(MIB_sysDescr), appl_internal_system, NULL);
        appl_internal_object(&OID(MIB_sysOID), appl_internal_system, NULL);
        appl_internal_object(&OID(MIB_sysUpTime), appl_internal_system, NULL);
        appl_internal_object(&OID(MIB_sysContact), appl_internal_system, NULL);
        appl_internal_object(&OID(MIB_sysName), appl_internal_system, NULL);
        appl_internal_object(&OID(MIB_sysLocation), appl_internal_system, NULL);
        appl_internal_object(&OID(MIB_sysServices), appl_internal_system, NULL);
        appl_internal_object(&OID(MIB_sysORLastChange), appl_sysorlastchange,
            NULL);

        appl_internal_object(&OID(MIB_sysORID), appl_sysortable,
            appl_sysortable_getnext);
        appl_internal_object(&OID(MIB_sysORDescr), appl_sysortable,
            appl_sysortable_getnext);
        appl_internal_object(&OID(MIB_sysORUpTime), appl_sysortable,
            appl_sysortable_getnext);

        appl_internal_region(&OID(MIB_snmp));
        appl_internal_object(&OID(MIB_snmpInPkts), appl_internal_snmp, NULL);
        appl_internal_object(&OID(MIB_snmpOutPkts), appl_internal_snmp, NULL);
        appl_internal_object(&OID(MIB_snmpInBadVersions), appl_internal_snmp,
           NULL);
        appl_internal_object(&OID(MIB_snmpInBadCommunityNames),
           appl_internal_snmp, NULL);
        appl_internal_object(&OID(MIB_snmpInBadCommunityUses),
           appl_internal_snmp, NULL);
        appl_internal_object(&OID(MIB_snmpInASNParseErrs), appl_internal_snmp,
            NULL);
        appl_internal_object(&OID(MIB_snmpInTooBigs), appl_internal_snmp, NULL);
        appl_internal_object(&OID(MIB_snmpInNoSuchNames), appl_internal_snmp,
            NULL);
        appl_internal_object(&OID(MIB_snmpInBadValues), appl_internal_snmp,
            NULL);
        appl_internal_object(&OID(MIB_snmpInReadOnlys), appl_internal_snmp,
            NULL);
        appl_internal_object(&OID(MIB_snmpInGenErrs), appl_internal_snmp, NULL);
        appl_internal_object(&OID(MIB_snmpInTotalReqVars), appl_internal_snmp,
            NULL);
        appl_internal_object(&OID(MIB_snmpInTotalSetVars), appl_internal_snmp,
            NULL);
        appl_internal_object(&OID(MIB_snmpInGetRequests), appl_internal_snmp,
            NULL);
        appl_internal_object(&OID(MIB_snmpInGetNexts), appl_internal_snmp,
            NULL);
        appl_internal_object(&OID(MIB_snmpInSetRequests), appl_internal_snmp,
            NULL);
        appl_internal_object(&OID(MIB_snmpInGetResponses), appl_internal_snmp,
            NULL);
        appl_internal_object(&OID(MIB_snmpInTraps), appl_internal_snmp, NULL);
        appl_internal_object(&OID(MIB_snmpOutTooBigs), appl_internal_snmp,
            NULL);
        appl_internal_object(&OID(MIB_snmpOutNoSuchNames), appl_internal_snmp,
            NULL);
        appl_internal_object(&OID(MIB_snmpOutBadValues), appl_internal_snmp,
            NULL);
        appl_internal_object(&OID(MIB_snmpOutGenErrs), appl_internal_snmp,
            NULL);
        appl_internal_object(&OID(MIB_snmpOutGetRequests), appl_internal_snmp,
            NULL);
        appl_internal_object(&OID(MIB_snmpOutGetNexts), appl_internal_snmp,
            NULL);
        appl_internal_object(&OID(MIB_snmpOutSetRequests), appl_internal_snmp,
            NULL);
        appl_internal_object(&OID(MIB_snmpOutGetResponses), appl_internal_snmp,
            NULL);
        appl_internal_object(&OID(MIB_snmpOutTraps), appl_internal_snmp, NULL);
        appl_internal_object(&OID(MIB_snmpEnableAuthenTraps),
            appl_internal_snmp, NULL);
        appl_internal_object(&OID(MIB_snmpSilentDrops), appl_internal_snmp,
            NULL);
        appl_internal_object(&OID(MIB_snmpProxyDrops), appl_internal_snmp,
            NULL);

        appl_internal_region(&OID(MIB_snmpV2));
        appl_internal_object(&OID(MIB_snmpEngineID), appl_internal_engine,
            NULL);
        appl_internal_object(&OID(MIB_snmpEngineBoots), appl_internal_engine,
            NULL);
        appl_internal_object(&OID(MIB_snmpEngineTime), appl_internal_engine,
            NULL);
        appl_internal_object(&OID(MIB_snmpEngineMaxMsgSize),
            appl_internal_engine, NULL);

        appl_internal_object(&OID(MIB_snmpUnavailableContexts),
            appl_targetmib, NULL);
        appl_internal_object(&OID(MIB_snmpUnknownContexts),
            appl_targetmib, NULL);

        appl_internal_object(&OID(MIB_usmStatsUnsupportedSecLevels),
            appl_internal_usmstats, NULL);
        appl_internal_object(&OID(MIB_usmStatsNotInTimeWindow),
            appl_internal_usmstats, NULL);
        appl_internal_object(&OID(MIB_usmStatsUnknownUserNames),
            appl_internal_usmstats, NULL);
        appl_internal_object(&OID(MIB_usmStatsUnknownEngineId),
            appl_internal_usmstats, NULL);
        appl_internal_object(&OID(MIB_usmStatsWrongDigests),
            appl_internal_usmstats, NULL);
        appl_internal_object(&OID(MIB_usmStatsDecryptionErrors),
            appl_internal_usmstats, NULL);

        while ((obj = RB_MIN(appl_internal_objects,
            &appl_internal_objects_conf)) != NULL) {
                RB_REMOVE(appl_internal_objects,
                    &appl_internal_objects_conf, obj);
                oid = obj->oid;
                oid.bo_id[oid.bo_n++] = 0;
                if (appl_register(NULL, 150, 1, &oid,
                    1, 1, 0, 0, &appl_config) != APPL_ERROR_NOERROR) {
                        free(obj->stringval);
                        free(obj);
                } else
                        RB_INSERT(appl_internal_objects, &appl_internal_objects,
                            obj);
        }
}

void
appl_internal_shutdown(void)
{
        struct appl_internal_object *object;

        while ((object = RB_ROOT(&appl_internal_objects)) != NULL) {
                RB_REMOVE(appl_internal_objects, &appl_internal_objects,
                    object);
                free(object->stringval);
                free(object);
        }

        appl_close(&appl_internal);
        appl_close(&appl_config);
}

void
appl_internal_region(struct ber_oid *oid)
{
        enum appl_error error;
        char oidbuf[1024];

        error = appl_register(NULL, 150, 1, oid, 0, 1, 0, 0, &appl_internal);
        /*
         * Ignore requestDenied, duplicateRegistration, and unsupportedContext
         */
        if (error == APPL_ERROR_PROCESSINGERROR ||
            error == APPL_ERROR_PARSEERROR)
                fatalx("internal: Failed to register %s", mib_oid2string(oid,
                    oidbuf, sizeof(oidbuf), snmpd_env->sc_oidfmt));
}

void
appl_internal_object(struct ber_oid *oid,
    struct ber_element *(*get)(struct ber_oid *),
    struct ber_element *(*getnext)(int8_t, struct ber_oid *))
{
        struct appl_internal_object *obj;
        char buf[1024];

        if ((obj = calloc(1, sizeof(*obj))) == NULL)
                fatal(NULL);
        obj->oid = *oid;
        obj->get = get;
        obj->getnext = getnext;
        obj->stringval = NULL;

        if (RB_INSERT(appl_internal_objects,
            &appl_internal_objects, obj) != NULL)
                fatalx("%s: %s already registered", __func__,
                    mib_oid2string(oid, buf, sizeof(buf),
                    snmpd_env->sc_oidfmt));
}

const char *
appl_internal_object_int(struct ber_oid *oid, int32_t val)
{
        struct appl_internal_object *obj;

        if ((obj = calloc(1, sizeof(*obj))) == NULL)
                return strerror(errno);
        obj->oid = *oid;
        obj->get = appl_internal_get_int;
        obj->getnext = NULL;
        obj->intval = val;
        obj->stringval = NULL;

        if (RB_INSERT(appl_internal_objects,
            &appl_internal_objects_conf, obj) != NULL) {
                free(obj);
                return "OID already defined";
        }
        return NULL;
}

const char *
appl_internal_object_string(struct ber_oid *oid, char *val)
{
        struct appl_internal_object *obj;

        if ((obj = calloc(1, sizeof(*obj))) == NULL)
                return strerror(errno);
        obj->oid = *oid;
        obj->get = appl_internal_get_string;
        obj->getnext = NULL;
        obj->stringval = val;

        if (RB_INSERT(appl_internal_objects,
            &appl_internal_objects_conf, obj) != NULL) {
                free(obj);
                return "OID already defined";
        }
        return NULL;
}

void
appl_internal_get(struct appl_backend *backend, __unused int32_t transactionid,
    int32_t requestid, __unused const char *ctx, struct appl_varbind *vblist)
{
        struct ber_oid oid;
        struct appl_internal_object *object;
        struct appl_varbind *vb, *resp;
        size_t i;
        int r;

        for (i = 0, vb = vblist; vb != NULL; vb = vb->av_next, i++)
                continue;

        if ((resp = calloc(i, sizeof(*resp))) == NULL) {
                log_warn("%s", backend->ab_name);
                appl_response(backend, requestid, APPL_ERROR_GENERR, 1, vblist);
                return;
        }

        for (i = 0, vb = vblist; vb != NULL; vb = vb->av_next, i++) {
                resp[i].av_oid = vb->av_oid;
                if ((object = appl_internal_object_parent(&vb->av_oid)) == NULL)
                        resp[i].av_value =
                            appl_exception(APPL_EXC_NOSUCHOBJECT);
                else {
                        oid = object->oid;
                        /* Add 0 element for scalar */
                        if (object->getnext == NULL)
                                oid.bo_id[oid.bo_n++] = 0;
                        r = ober_oid_cmp(&vb->av_oid, &oid);
                        if ((r == 0 && object->getnext == NULL) ||
                            (r == 2 && object->getnext != NULL))
                                resp[i].av_value = object->get(&resp[i].av_oid);
                        else
                                resp[i].av_value =
                                    appl_exception(APPL_EXC_NOSUCHINSTANCE);
                }
                if (resp[i].av_value == NULL) {
                        log_warnx("%s: Failed to get value", backend->ab_name);
                        goto fail;
                }
                resp[i].av_next = &resp[i + 1];
        }
        resp[i - 1].av_next = NULL;

        appl_response(backend, requestid, APPL_ERROR_NOERROR, 0, resp);

        free(resp);
        return;

 fail:
        for (vb = resp; vb != NULL; vb = vb->av_next)
                ober_free_elements(vb->av_value);
        free(resp);
        appl_response(backend, requestid, APPL_ERROR_GENERR, i + 1, vblist);
}

void
appl_internal_getnext(struct appl_backend *backend,
    __unused int32_t transactionid, int32_t requestid, __unused const char *ctx,
    struct appl_varbind *vblist)
{
        struct ber_oid oid;
        struct appl_internal_object *object, search;
        struct appl_varbind *vb, *resp;
        size_t i;
        int r;
        int8_t include;

        for (i = 0, vb = vblist; vb != NULL; vb = vb->av_next, i++)
                continue;

        if ((resp = calloc(i, sizeof(*resp))) == NULL) {
                log_warn("%s", backend->ab_name);
                appl_response(backend, requestid, APPL_ERROR_GENERR, 1, vblist);
                return;
        }

        for (i = 0, vb = vblist; vb != NULL; vb = vb->av_next, i++) {
                resp[i].av_oid = vb->av_oid;
                object = appl_internal_object_parent(&vb->av_oid);
                if (object == NULL) {
                        search.oid = vb->av_oid;
                        object = RB_NFIND(appl_internal_objects,
                            &appl_internal_objects, &search);
                }

                include = vb->av_include;
                for (; object != NULL; object = RB_NEXT(appl_internal_objects,
                    &appl_internal_objects, object), include = 1) {
                        if (object->getnext == NULL) {
                                oid = object->oid;
                                oid.bo_id[oid.bo_n++] = 0;
                                r = ober_oid_cmp(&resp[i].av_oid, &oid);
                                if (r > 0 || (r == 0 && !include))
                                        continue;
                                resp[i].av_oid = oid;
                                resp[i].av_value = object->get(&oid);
                                break;
                        }
                        /* non-scalar */
                        if (ober_oid_cmp(&object->oid, &resp[i].av_oid) > 0) {
                                include = 1;
                                resp[i].av_oid = object->oid;
                        }

                        resp[i].av_value =
                            object->getnext(include, &resp[i].av_oid);
                        if (resp[i].av_value == NULL ||
                            resp[i].av_value->be_class != BER_CLASS_CONTEXT)
                                break;
                        /* endOfMibView */
                        ober_free_elements(resp[i].av_value);
                        resp[i].av_value = NULL;
                }
                if (ober_oid_cmp(&resp[i].av_oid, &vb->av_oid_end) >= 0 ||
                    object == NULL) {
                        resp[i].av_oid = vb->av_oid;
                        ober_free_elements(resp[i].av_value);
                        resp[i].av_value =
                            appl_exception(APPL_EXC_ENDOFMIBVIEW);
                }
                if (resp[i].av_value == NULL) {
                        log_warnx("%s: Failed to get value", backend->ab_name);
                        goto fail;
                }
                resp[i].av_next = &resp[i + 1];
        }
        resp[i - 1].av_next = NULL;

        appl_response(backend, requestid, APPL_ERROR_NOERROR, 0, resp);

        free(resp);
        return;

 fail:
        for (vb = resp; vb != NULL; vb = vb->av_next)
                ober_free_elements(vb->av_value);
        free(resp);
        appl_response(backend, requestid, APPL_ERROR_GENERR, i + 1, vblist);
}

struct ber_element *
appl_internal_snmp(struct ber_oid *oid)
{
        struct snmp_stats *stats = &snmpd_env->sc_stats;
        struct ber_element *value = NULL;

        if (ober_oid_cmp(oid, &OID(MIB_snmpEnableAuthenTraps, 0)) == 0)
                return ober_add_integer(NULL,
                    stats->snmp_enableauthentraps ? 1 : 2);
        if (ober_oid_cmp(&OID(MIB_snmpInPkts, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_inpkts);
        else if (ober_oid_cmp(&OID(MIB_snmpOutPkts, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_outpkts);
        else if (ober_oid_cmp(&OID(MIB_snmpInBadVersions, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_inbadversions);
        else if (ober_oid_cmp(&OID(MIB_snmpInBadCommunityNames, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_inbadcommunitynames);
        else if (ober_oid_cmp(&OID(MIB_snmpInBadCommunityUses, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_inbadcommunityuses);
        else if (ober_oid_cmp(&OID(MIB_snmpInASNParseErrs, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_inasnparseerrs);
        else if (ober_oid_cmp(&OID(MIB_snmpInTooBigs, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_intoobigs);
        else if (ober_oid_cmp(&OID(MIB_snmpInNoSuchNames, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_innosuchnames);
        else if (ober_oid_cmp(&OID(MIB_snmpInBadValues, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_inbadvalues);
        else if (ober_oid_cmp(&OID(MIB_snmpInReadOnlys, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_inreadonlys);
        else if (ober_oid_cmp(&OID(MIB_snmpInGenErrs, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_ingenerrs);
        else if (ober_oid_cmp(&OID(MIB_snmpInTotalReqVars, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_intotalreqvars);
        else if (ober_oid_cmp(&OID(MIB_snmpInTotalSetVars, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_intotalsetvars);
        else if (ober_oid_cmp(&OID(MIB_snmpInGetRequests, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_ingetrequests);
        else if (ober_oid_cmp(&OID(MIB_snmpInGetNexts, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_ingetnexts);
        else if (ober_oid_cmp(&OID(MIB_snmpInSetRequests, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_insetrequests);
        else if (ober_oid_cmp(&OID(MIB_snmpInGetResponses, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_ingetresponses);
        else if (ober_oid_cmp(&OID(MIB_snmpInTraps, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_intraps);
        else if (ober_oid_cmp(&OID(MIB_snmpOutTooBigs, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_outtoobigs);
        else if (ober_oid_cmp(&OID(MIB_snmpOutNoSuchNames, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_outnosuchnames);
        else if (ober_oid_cmp(&OID(MIB_snmpOutBadValues, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_outbadvalues);
        else if (ober_oid_cmp(&OID(MIB_snmpOutGenErrs, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_outgenerrs);
        else if (ober_oid_cmp(&OID(MIB_snmpOutGetRequests, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_outgetrequests);
        else if (ober_oid_cmp(&OID(MIB_snmpOutGetNexts, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_outgetnexts);
        else if (ober_oid_cmp(&OID(MIB_snmpOutSetRequests, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_outsetrequests);
        else if (ober_oid_cmp(&OID(MIB_snmpOutGetResponses, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_outgetresponses);
        else if (ober_oid_cmp(&OID(MIB_snmpOutTraps, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_outtraps);
        else if (ober_oid_cmp(&OID(MIB_snmpSilentDrops, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_silentdrops);
        else if (ober_oid_cmp(&OID(MIB_snmpProxyDrops, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_proxydrops);

        if (value != NULL)
                ober_set_header(value, BER_CLASS_APPLICATION, SNMP_T_COUNTER32);
        return value;
}

struct ber_element *
appl_internal_engine(struct ber_oid *oid)
{
        if (ober_oid_cmp(&OID(MIB_snmpEngineID, 0), oid) == 0)
                return ober_add_nstring(NULL, snmpd_env->sc_engineid.value,
                    snmpd_env->sc_engineid.length);
        else if (ober_oid_cmp(&OID(MIB_snmpEngineBoots, 0), oid) == 0)
                return ober_add_integer(NULL, snmpd_env->sc_engine_boots);
        else if (ober_oid_cmp(&OID(MIB_snmpEngineTime, 0), oid) == 0)
                return ober_add_integer(NULL, snmpd_engine_time());
        else if (ober_oid_cmp(&OID(MIB_snmpEngineMaxMsgSize, 0), oid) == 0)
                return ober_add_integer(NULL, READ_BUF_SIZE);
        return NULL;
}

struct ber_element *
appl_internal_usmstats(struct ber_oid *oid)
{
        struct snmp_stats *stats = &snmpd_env->sc_stats;
        struct ber_element *value = NULL;

        if (ober_oid_cmp(&OID(MIB_usmStatsUnsupportedSecLevels, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_usmbadseclevel);
        else if (ober_oid_cmp(&OID(MIB_usmStatsNotInTimeWindow, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_usmtimewindow);
        else if (ober_oid_cmp(&OID(MIB_usmStatsUnknownUserNames, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_usmnosuchuser);
        else if (ober_oid_cmp(&OID(MIB_usmStatsUnknownEngineId, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_usmnosuchengine);
        else if (ober_oid_cmp(&OID(MIB_usmStatsWrongDigests, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_usmwrongdigest);
        else if (ober_oid_cmp(&OID(MIB_usmStatsDecryptionErrors, 0), oid) == 0)
                value = ober_add_integer(NULL, stats->snmp_usmdecrypterr);

        if (value != NULL)
                ober_set_header(value, BER_CLASS_APPLICATION, SNMP_T_COUNTER32);

        return value;
}

struct ber_element *
appl_internal_system(struct ber_oid *oid)
{
        struct snmp_system *s = &snmpd_env->sc_system;
        struct ber_element *value = NULL;

        if (ober_oid_cmp(&OID(MIB_sysDescr, 0), oid) == 0)
                return ober_add_string(NULL, s->sys_descr);
        else if (ober_oid_cmp(&OID(MIB_sysOID, 0), oid) == 0)
                return ober_add_oid(NULL, &s->sys_oid);
        else if (ober_oid_cmp(&OID(MIB_sysUpTime, 0), oid) == 0) {
                value = ober_add_integer(NULL, appl_sysuptime(NULL));
                ober_set_header(value, BER_CLASS_APPLICATION, SNMP_T_TIMETICKS);
        } else if (ober_oid_cmp(&OID(MIB_sysContact, 0), oid) == 0)
                return ober_add_string(NULL, s->sys_contact);
        else if (ober_oid_cmp(&OID(MIB_sysName, 0), oid) == 0)
                return ober_add_string(NULL, s->sys_name);
        else if (ober_oid_cmp(&OID(MIB_sysLocation, 0), oid) == 0)
                return ober_add_string(NULL, s->sys_location);
        else if (ober_oid_cmp(&OID(MIB_sysServices, 0), oid) == 0)
                return ober_add_integer(NULL, s->sys_services);
        return value;
}

struct ber_element *
appl_internal_get_int(struct ber_oid *oid)
{
        struct appl_internal_object *obj;

        obj = appl_internal_object_parent(oid);
        return ober_add_integer(NULL, obj->intval);
}

struct ber_element *
appl_internal_get_string(struct ber_oid *oid)
{
        struct appl_internal_object *obj;

        obj = appl_internal_object_parent(oid);
        return ober_add_string(NULL, obj->stringval);
}

struct appl_internal_object *
appl_internal_object_parent(struct ber_oid *oid)
{
        struct appl_internal_object *object, search;

        search.oid = *oid;
        do {
                if ((object = RB_FIND(appl_internal_objects,
                    &appl_internal_objects, &search)) != NULL)
                        return object;
        } while (--search.oid.bo_n > 0);

        return NULL;
}

int
appl_internal_object_cmp(struct appl_internal_object *o1,
    struct appl_internal_object *o2)
{
        return ober_oid_cmp(&o1->oid, &o2->oid);
}

RB_GENERATE_STATIC(appl_internal_objects, appl_internal_object, entry,
    appl_internal_object_cmp);