/* Copyright (C) 2015-2021 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 "detect.h"

#include "pkt-var.h"

#include "conf.h"

#include "threads.h"

#include "threadvars.h"

#include "tm-threads.h"

#include "util-print.h"

#include "util-unittest.h"

#include "util-buffer.h"

#include "util-debug.h"

#include "app-layer.h"

#include "app-layer-parser.h"

#include "app-layer-dnp3.h"

#include "app-layer-dnp3-objects.h"

#include "detect-dnp3.h"

#include "output.h"

#include "output-json.h"

#include "output-json-dnp3.h"

#include "output-json-dnp3-objects.h"

typedef struct LogDNP3FileCtx_ {

    uint32_t    flags;

    uint8_t     include_object_data;

    OutputJsonCtx *eve_ctx;

} LogDNP3FileCtx;

typedef struct LogDNP3LogThread_ {

    LogDNP3FileCtx *dnp3log_ctx;

    OutputJsonThreadCtx *ctx;

} LogDNP3LogThread;

static void JsonDNP3LogLinkControl(SCJsonBuilder *js, uint8_t lc)

{

    SCJbSetBool(js, "dir", DNP3_LINK_DIR(lc));

    SCJbSetBool(js, "pri", DNP3_LINK_PRI(lc));

    SCJbSetBool(js, "fcb", DNP3_LINK_FCB(lc));

    SCJbSetBool(js, "fcv", DNP3_LINK_FCV(lc));

    SCJbSetUint(js, "function_code", DNP3_LINK_FC(lc));

}

static void JsonDNP3LogIin(SCJsonBuilder *js, uint16_t iin)

{

    if (iin) {

        SCJbOpenArray(js, "indicators");

        int mapping = 0;

        do {

            if (iin & DNP3IndicatorsMap[mapping].value) {

                SCJbAppendString(js, DNP3IndicatorsMap[mapping].name);

            }

            mapping++;

        } while (DNP3IndicatorsMap[mapping].name != NULL);

        SCJbClose(js);

    }

}

static void JsonDNP3LogApplicationControl(SCJsonBuilder *js, uint8_t ac)

{

    SCJbSetBool(js, "fir", DNP3_APP_FIR(ac));

    SCJbSetBool(js, "fin", DNP3_APP_FIN(ac));

    SCJbSetBool(js, "con", DNP3_APP_CON(ac));

    SCJbSetBool(js, "uns", DNP3_APP_UNS(ac));

    SCJbSetUint(js, "sequence", DNP3_APP_SEQ(ac));

}

/**

 * \brief Log the items (points) for an object.

 *

 * TODO: Autogenerate this function based on object definitions.

 */

static void JsonDNP3LogObjectItems(SCJsonBuilder *js, DNP3Object *object)

{

    DNP3Point *item;

    TAILQ_FOREACH(item, object->points, next) {

        SCJbStartObject(js);

        SCJbSetUint(js, "prefix", item->prefix);

        SCJbSetUint(js, "index", item->index);

        if (DNP3PrefixIsSize(object->prefix_code)) {

            SCJbSetUint(js, "size", item->size);

        }

        OutputJsonDNP3SetItem(js, object, item);

        SCJbClose(js);

    }

}

/**

 * \brief Log the application layer objects.

 *

 * \param objects A list of DNP3 objects.

 * \param jb A SCJsonBuilder instance with an open array.

 */

static void JsonDNP3LogObjects(SCJsonBuilder *js, DNP3ObjectList *objects)

{

    DNP3Object *object;

    TAILQ_FOREACH(object, objects, next) {

        SCJbStartObject(js);

        SCJbSetUint(js, "group", object->group);

        SCJbSetUint(js, "variation", object->variation);

        SCJbSetUint(js, "qualifier", object->qualifier);

        SCJbSetUint(js, "prefix_code", object->prefix_code);

        SCJbSetUint(js, "range_code", object->range_code);

        SCJbSetUint(js, "start", object->start);

        SCJbSetUint(js, "stop", object->stop);

        SCJbSetUint(js, "count", object->count);

        if (object->points != NULL && !TAILQ_EMPTY(object->points)) {

            SCJbOpenArray(js, "points");

            JsonDNP3LogObjectItems(js, object);

            SCJbClose(js);

        }

        SCJbClose(js);

    }

}

static void JsonDNP3LogRequest(SCJsonBuilder *js, DNP3Transaction *dnp3tx)

{

    JB_SET_STRING(js, "type", "request");

    SCJbOpenObject(js, "control");

    JsonDNP3LogLinkControl(js, dnp3tx->lh.control);

    SCJbClose(js);

    SCJbSetUint(js, "src", DNP3_SWAP16(dnp3tx->lh.src));

    SCJbSetUint(js, "dst", DNP3_SWAP16(dnp3tx->lh.dst));

    SCJbOpenObject(js, "application");

    SCJbOpenObject(js, "control");

    JsonDNP3LogApplicationControl(js, dnp3tx->ah.control);

    SCJbClose(js);

    SCJbSetUint(js, "function_code", dnp3tx->ah.function_code);

    if (!TAILQ_EMPTY(&dnp3tx->objects)) {

        SCJbOpenArray(js, "objects");

        JsonDNP3LogObjects(js, &dnp3tx->objects);

        SCJbClose(js);

    }

    SCJbSetBool(js, "complete", dnp3tx->complete);

    /* Close application. */

    SCJbClose(js);

}

static void JsonDNP3LogResponse(SCJsonBuilder *js, DNP3Transaction *dnp3tx)

{

    if (dnp3tx->ah.function_code == DNP3_APP_FC_UNSOLICITED_RESP) {

        JB_SET_STRING(js, "type", "unsolicited_response");

    } else {

        JB_SET_STRING(js, "type", "response");

    }

    SCJbOpenObject(js, "control");

    JsonDNP3LogLinkControl(js, dnp3tx->lh.control);

    SCJbClose(js);

    SCJbSetUint(js, "src", DNP3_SWAP16(dnp3tx->lh.src));

    SCJbSetUint(js, "dst", DNP3_SWAP16(dnp3tx->lh.dst));

    SCJbOpenObject(js, "application");

    SCJbOpenObject(js, "control");

    JsonDNP3LogApplicationControl(js, dnp3tx->ah.control);

    SCJbClose(js);

    SCJbSetUint(js, "function_code", dnp3tx->ah.function_code);

    if (!TAILQ_EMPTY(&dnp3tx->objects)) {

        SCJbOpenArray(js, "objects");

        JsonDNP3LogObjects(js, &dnp3tx->objects);

        SCJbClose(js);

    }

    SCJbSetBool(js, "complete", dnp3tx->complete);

    /* Close application. */

    SCJbClose(js);

    SCJbOpenObject(js, "iin");

    JsonDNP3LogIin(js, (uint16_t)(dnp3tx->iin.iin1 << 8 | dnp3tx->iin.iin2));

    SCJbClose(js);

}

bool AlertJsonDnp3(void *vtx, SCJsonBuilder *js)

{

    DNP3Transaction *tx = (DNP3Transaction *)vtx;

    if (tx->done && tx->buffer == NULL) {

        /* Carrier TX for app-layer event, don't log. */

        return false;

    }

    bool logged = false;

    SCJbOpenObject(js, "dnp3");

    if (tx->is_request && tx->done) {

        SCJbOpenObject(js, "request");

        JsonDNP3LogRequest(js, tx);

        SCJbClose(js);

        logged = true;

    }

    if (!tx->is_request && tx->done) {

        SCJbOpenObject(js, "response");

        JsonDNP3LogResponse(js, tx);

        SCJbClose(js);

        logged = true;

    }

    SCJbClose(js);

    return logged;

}

static int JsonDNP3LoggerToServer(ThreadVars *tv, void *thread_data,

    const Packet *p, Flow *f, void *state, void *vtx, uint64_t tx_id)

{

    SCEnter();

    LogDNP3LogThread *thread = (LogDNP3LogThread *)thread_data;

    DNP3Transaction *tx = vtx;

    SCJsonBuilder *js =

            CreateEveHeader(p, LOG_DIR_FLOW, "dnp3", NULL, thread->dnp3log_ctx->eve_ctx);

    if (unlikely(js == NULL)) {

        return TM_ECODE_OK;

    }

    SCJbOpenObject(js, "dnp3");

    JsonDNP3LogRequest(js, tx);

    SCJbClose(js);

    OutputJsonBuilderBuffer(tv, p, p->flow, js, thread->ctx);

    SCJbFree(js);

    SCReturnInt(TM_ECODE_OK);

}

static int JsonDNP3LoggerToClient(ThreadVars *tv, void *thread_data,

    const Packet *p, Flow *f, void *state, void *vtx, uint64_t tx_id)

{

    SCEnter();

    LogDNP3LogThread *thread = (LogDNP3LogThread *)thread_data;

    DNP3Transaction *tx = vtx;

    SCJsonBuilder *js =

            CreateEveHeader(p, LOG_DIR_FLOW, "dnp3", NULL, thread->dnp3log_ctx->eve_ctx);

    if (unlikely(js == NULL)) {

        return TM_ECODE_OK;

    }

    SCJbOpenObject(js, "dnp3");

    JsonDNP3LogResponse(js, tx);

    SCJbClose(js);

    OutputJsonBuilderBuffer(tv, p, p->flow, js, thread->ctx);

    SCJbFree(js);

    SCReturnInt(TM_ECODE_OK);

}

static int JsonDNP3Logger(ThreadVars *tv, void *thread_data, const Packet *p, Flow *f, void *state,

        void *vtx, uint64_t tx_id)

{

    SCEnter();

    DNP3Transaction *tx = vtx;

    if (tx->done && tx->buffer == NULL) {

        /* Carrier TX for app-layer event, don't log. */

        SCReturnInt(TM_ECODE_OK);

    }

    if (tx->is_request && tx->done) {

        JsonDNP3LoggerToServer(tv, thread_data, p, f, state, vtx, tx_id);

    } else if (!tx->is_request && tx->done) {

        JsonDNP3LoggerToClient(tv, thread_data, p, f, state, vtx, tx_id);

    }

    SCReturnInt(TM_ECODE_OK);

}

static void OutputDNP3LogDeInitCtxSub(OutputCtx *output_ctx)

{

    SCLogDebug("cleaning up sub output_ctx %p", output_ctx);

    LogDNP3FileCtx *dnp3log_ctx = (LogDNP3FileCtx *)output_ctx->data;

    SCFree(dnp3log_ctx);

    SCFree(output_ctx);

}

static OutputInitResult OutputDNP3LogInitSub(SCConfNode *conf, OutputCtx *parent_ctx)

{

    OutputInitResult result = { NULL, false };

    OutputJsonCtx *json_ctx = parent_ctx->data;

    LogDNP3FileCtx *dnp3log_ctx = SCCalloc(1, sizeof(*dnp3log_ctx));

    if (unlikely(dnp3log_ctx == NULL)) {

        return result;

    }

    dnp3log_ctx->eve_ctx = json_ctx;

    OutputCtx *output_ctx = SCCalloc(1, sizeof(*output_ctx));

    if (unlikely(output_ctx == NULL)) {

        SCFree(dnp3log_ctx);

        return result;

    }

    output_ctx->data = dnp3log_ctx;

    output_ctx->DeInit = OutputDNP3LogDeInitCtxSub;

    SCLogInfo("DNP3 log sub-module initialized.");

    SCAppLayerParserRegisterLogger(IPPROTO_TCP, ALPROTO_DNP3);

    result.ctx = output_ctx;

    result.ok = true;

    return result;

}

static TmEcode JsonDNP3LogThreadInit(ThreadVars *t, const void *initdata, void **data)

{

    LogDNP3LogThread *thread = SCCalloc(1, sizeof(*thread));

    if (unlikely(thread == NULL)) {

        return TM_ECODE_FAILED;

    }

    if (initdata == NULL) {

        SCLogDebug("Error getting context for DNP3.  \"initdata\" is NULL.");

        goto error_exit;

    }

    thread->dnp3log_ctx = ((OutputCtx *)initdata)->data;

    thread->ctx = CreateEveThreadCtx(t, thread->dnp3log_ctx->eve_ctx);

    if (thread->ctx == NULL) {

        goto error_exit;

    }

    *data = (void *)thread;

    return TM_ECODE_OK;

error_exit:

    SCFree(thread);

    return TM_ECODE_FAILED;

}

static TmEcode JsonDNP3LogThreadDeinit(ThreadVars *t, void *data)

{

    LogDNP3LogThread *thread = (LogDNP3LogThread *)data;

    if (thread == NULL) {

        return TM_ECODE_OK;

    }

    FreeEveThreadCtx(thread->ctx);

    SCFree(thread);

    return TM_ECODE_OK;

}

void JsonDNP3LogRegister(void)

{

    OutputRegisterTxSubModule(LOGGER_JSON_TX, "eve-log", "JsonDNP3Log", "eve-log.dnp3",

            OutputDNP3LogInitSub, ALPROTO_DNP3, JsonDNP3Logger, JsonDNP3LogThreadInit,

            JsonDNP3LogThreadDeinit);

}