/* Copyright (C) 2022 Open Information Security Foundation

 *

 * You can copy, redistribute or modify this Program under the terms of

 * the GNU General Public License version 2 as published by the Free

 * Software Foundation.

 *

 * This program 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

 * version 2 along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

 * 02110-1301, USA.

 */

#include "suricata-common.h"

#include "rust.h"

#include "detect-snmp-usm.h"

#include "detect-engine.h"

#include "detect-engine-mpm.h"

#include "detect-engine-prefilter.h"

#include "detect-parse.h"

static int g_buffer_id = 0;

static int DetectSNMPUsmSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)

{

    if (DetectBufferSetActiveList(de_ctx, s, g_buffer_id) < 0)

        return -1;

    if (DetectSignatureSetAppProto(s, ALPROTO_SNMP) != 0)

        return -1;

    return 0;

}

static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,

        const DetectEngineTransforms *transforms, Flow *f, const uint8_t flow_flags, void *txv,

        const int list_id)

{

    InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);

    if (buffer->inspect == NULL) {

        uint32_t data_len = 0;

        const uint8_t *data = NULL;

        rs_snmp_tx_get_usm(txv, &data, &data_len);

        if (data == NULL || data_len == 0) {

            return NULL;

        }

        InspectionBufferSetup(det_ctx, list_id, buffer, data, data_len);

        InspectionBufferApplyTransforms(buffer, transforms);

    }

    return buffer;

}

void DetectSNMPUsmRegister(void)

{

    sigmatch_table[DETECT_AL_SNMP_USM].name = "snmp.usm";

    sigmatch_table[DETECT_AL_SNMP_USM].desc = "SNMP content modifier to match on the SNMP usm";

    sigmatch_table[DETECT_AL_SNMP_USM].Setup = DetectSNMPUsmSetup;

    sigmatch_table[DETECT_AL_SNMP_USM].flags |= SIGMATCH_NOOPT | SIGMATCH_INFO_STICKY_BUFFER;

    /* register inspect engines */

    DetectAppLayerInspectEngineRegister2("snmp.usm", ALPROTO_SNMP, SIG_FLAG_TOSERVER, 0,

            DetectEngineInspectBufferGeneric, GetData);

    DetectAppLayerMpmRegister2("snmp.usm", SIG_FLAG_TOSERVER, 2, PrefilterGenericMpmRegister,

            GetData, ALPROTO_SNMP, 0);

    DetectAppLayerInspectEngineRegister2("snmp.usm", ALPROTO_SNMP, SIG_FLAG_TOCLIENT, 0,

            DetectEngineInspectBufferGeneric, GetData);

    DetectAppLayerMpmRegister2("snmp.usm", SIG_FLAG_TOCLIENT, 2, PrefilterGenericMpmRegister,

            GetData, ALPROTO_SNMP, 0);

    DetectBufferTypeSetDescriptionByName("snmp.usm", "SNMP USM");

    g_buffer_id = DetectBufferTypeGetByName("snmp.usm");

}