/* Copyright (C) 2020 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.

 */

/**

 * \file

 *

 * \author Sascha Steinbiss <sascha@steinbiss.name>

 */

#include "suricata-common.h"

#include "conf.h"

#include "detect.h"

#include "detect-parse.h"

#include "detect-engine.h"

#include "detect-engine-content-inspection.h"

#include "detect-mqtt-qos.h"

#include "util-byte.h"

#include "util-unittest.h"

#include "rust.h"

static int mqtt_qos_id = 0;

static int DetectMQTTQosMatch(DetectEngineThreadCtx *det_ctx,

                               Flow *f, uint8_t flags, void *state,

                               void *txv, const Signature *s,

                               const SigMatchCtx *ctx);

static int DetectMQTTQosSetup (DetectEngineCtx *, Signature *, const char *);

void MQTTQosRegisterTests(void);

void DetectMQTTQosFree(DetectEngineCtx *de_ctx, void *);

/**

 * \brief Registration function for mqtt.qos: keyword

 */

void DetectMQTTQosRegister (void)

{

    sigmatch_table[DETECT_AL_MQTT_QOS].name = "mqtt.qos";

    sigmatch_table[DETECT_AL_MQTT_QOS].desc = "match MQTT fixed header QOS level";

    sigmatch_table[DETECT_AL_MQTT_QOS].url = "/rules/mqtt-keywords.html#mqtt-qos";

    sigmatch_table[DETECT_AL_MQTT_QOS].AppLayerTxMatch = DetectMQTTQosMatch;

    sigmatch_table[DETECT_AL_MQTT_QOS].Setup = DetectMQTTQosSetup;

    sigmatch_table[DETECT_AL_MQTT_QOS].Free  = DetectMQTTQosFree;

#ifdef UNITTESTS

    sigmatch_table[DETECT_AL_MQTT_QOS].RegisterTests = MQTTQosRegisterTests;

#endif

    DetectAppLayerInspectEngineRegister2(

            "mqtt.qos", ALPROTO_MQTT, SIG_FLAG_TOSERVER, 1, DetectEngineInspectGenericList, NULL);

    mqtt_qos_id = DetectBufferTypeGetByName("mqtt.qos");

}

/**

 * \internal

 * \brief Function to match fixed header QOS field of an MQTT Tx

 *

 * \param det_ctx Pointer to the pattern matcher thread.

 * \param f       Pointer to the current flow.

 * \param flags   Flags.

 * \param state   App layer state.

 * \param txv     Pointer to the transaction.

 * \param s       Pointer to the Signature.

 * \param ctx     Pointer to the sigmatch that we will cast into uint8_t.

 *

 * \retval 0 no match.

 * \retval 1 match.

 */

static int DetectMQTTQosMatch(DetectEngineThreadCtx *det_ctx,

                               Flow *f, uint8_t flags, void *state,

                               void *txv, const Signature *s,

                               const SigMatchCtx *ctx)

{

    const uint8_t *de = (const uint8_t *)ctx;

    if (!de)

        return 0;

    return rs_mqtt_tx_has_qos(txv, *de);

}

/**

 * \internal

 * \brief This function is used to parse options passed via mqtt.qos: keyword

 *

 * \param rawstr Pointer to the user provided options

 *

 * \retval de pointer to DetectMQTTQosData on success

 * \retval NULL on failure

 */

static uint8_t *DetectMQTTQosParse(const char *rawstr)

{

    uint8_t *de = NULL;

    int ret = 0;

    uint8_t val;

    ret = StringParseU8RangeCheck(&val, 10, 0, rawstr, 0, 2);

    if (ret <= 0) {

        SCLogError("invalid MQTT QOS level: %s", rawstr);

        return NULL;

    }

    de = SCMalloc(sizeof(uint8_t));

    if (unlikely(de == NULL))

        return NULL;

    *de = val;

    return de;

}

/**

 * \internal

 * \brief this function is used to add the parsed sigmatch  into the current signature

 *

 * \param de_ctx pointer to the Detection Engine Context

 * \param s pointer to the Current Signature

 * \param rawstr pointer to the user provided options

 *

 * \retval 0 on Success

 * \retval -1 on Failure

 */

static int DetectMQTTQosSetup(DetectEngineCtx *de_ctx, Signature *s, const char *rawstr)

{

    uint8_t *de = NULL;

    SigMatch *sm = NULL;

    if (DetectSignatureSetAppProto(s, ALPROTO_MQTT) < 0)

        return -1;

    de = DetectMQTTQosParse(rawstr);

    if (de == NULL)

        goto error;

    sm = SigMatchAlloc();

    if (sm == NULL)

        goto error;

    sm->type = DETECT_AL_MQTT_QOS;

    sm->ctx = (SigMatchCtx *)de;

    SigMatchAppendSMToList(s, sm, mqtt_qos_id);

    return 0;

error:

    if (de != NULL)

        SCFree(de);

    if (sm != NULL)

        SCFree(sm);

    return -1;

}

/**

 * \internal

 * \brief this function will free memory associated with DetectMQTTQosData

 *

 * \param de pointer to DetectMQTTQosData

 */

void DetectMQTTQosFree(DetectEngineCtx *de_ctx, void *de_ptr)

{

    if (de_ptr != NULL)

        SCFree(de_ptr);

}

/*

 * ONLY TESTS BELOW THIS COMMENT

 */

#ifdef UNITTESTS

/**

 * \test MQTTQosTestParse01 is a test for a valid value

 *

 *  \retval 1 on success

 *  \retval 0 on failure

 */

static int MQTTQosTestParse01 (void)

{

    uint8_t *de = NULL;

    de = DetectMQTTQosParse("0");

    FAIL_IF_NULL(de);

    FAIL_IF_NOT(*de == 0);

    DetectMQTTQosFree(NULL, de);

    de = DetectMQTTQosParse("   0");

    FAIL_IF_NULL(de);

    FAIL_IF_NOT(*de == 0);

    DetectMQTTQosFree(NULL, de);

    de = DetectMQTTQosParse("1");

    FAIL_IF_NULL(de);

    FAIL_IF_NOT(*de == 1);

    DetectMQTTQosFree(NULL, de);

    de = DetectMQTTQosParse("2");

    FAIL_IF_NULL(de);

    FAIL_IF_NOT(*de == 2);

    DetectMQTTQosFree(NULL, de);

    PASS;

}

/**

 * \test MQTTQosTestParse02 is a test for an invalid value

 *

 *  \retval 1 on success

 *  \retval 0 on failure

 */

static int MQTTQosTestParse02 (void)

{

    uint8_t *de = NULL;

    de = DetectMQTTQosParse("3");

    if (de) {

        DetectMQTTQosFree(NULL, de);

        FAIL;

    }

    PASS;

}

/**

 * \test MQTTQosTestParse04 is a test for an invalid value

 *

 *  \retval 1 on success

 *  \retval 0 on failure

 */

static int MQTTQosTestParse03 (void)

{

    uint8_t *de = NULL;

    de = DetectMQTTQosParse("12");

    if (de) {

        DetectMQTTQosFree(NULL, de);

        FAIL;

    }

    PASS;

}

#endif /* UNITTESTS */

/**

 * \brief this function registers unit tests for MQTTQos

 */

void MQTTQosRegisterTests(void)

{

#ifdef UNITTESTS

    UtRegisterTest("MQTTQosTestParse01", MQTTQosTestParse01);

    UtRegisterTest("MQTTQosTestParse02", MQTTQosTestParse02);

    UtRegisterTest("MQTTQosTestParse03", MQTTQosTestParse03);

#endif /* UNITTESTS */

}