/* file-dlt.c

 * DLT File Format.

 * By Dr. Lars Voelker <lars.voelker@technica-engineering.de>

 * Copyright 2022-2022 Dr. Lars Voelker

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998 Gerald Combs

 *

 * SPDX-License-Identifier: GPL-2.0-or-later

 *

 * This dissector allows to parse DLT files.

 */

 /*

  * Sources for specification:

  * https://www.autosar.org/fileadmin/standards/R22-11/CP/AUTOSAR_SWS_DiagnosticLogAndTrace.pdf

  * https://www.autosar.org/fileadmin/standards/R22-11/FO/AUTOSAR_PRS_LogAndTraceProtocol.pdf

  * https://github.com/COVESA/dlt-viewer

  */

#include "config.h"

#include <epan/packet.h>

#include <wsutil/array.h>

static int proto_dlt;

static int hf_dlt_file_magic;

static int hf_dlt_file_tstamp_s;

static int hf_dlt_file_tstamp_us;

static int hf_dlt_file_ecuid;

static int hf_dlt_file_header_type;

static int hf_dlt_file_message_counter;

static int hf_dlt_file_length;

static int hf_dlt_file_data;

static int ett_dlt;

static int ett_dlt_item;

void proto_register_file_dlt(void);

void proto_reg_handoff_file_dlt(void);

#define MAGIC_NUMBER_SIZE 4

static const uint8_t dlt_file_magic[MAGIC_NUMBER_SIZE] = { 'D', 'L', 'T', 0x01 };

static int

dissect_dlt(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) {

    volatile int     offset = 0;

    proto_tree      *dlt_tree;

    proto_tree      *item_tree;

    proto_item      *ti;

    proto_item      *ti_item;

    uint32_t         len = 0;

    if (tvb_captured_length(tvb) < 16 || tvb_memeql(tvb, 0, dlt_file_magic, MAGIC_NUMBER_SIZE) != 0) {

        /* does not start with DLT\x1, so this is not DLT it seems */

        return 0;

    }

    ti = proto_tree_add_item(tree, proto_dlt, tvb, offset, -1, ENC_NA);

    dlt_tree = proto_item_add_subtree(ti, ett_dlt);

    int tvb_length = tvb_captured_length(tvb);

    while (offset + 20 <= tvb_length) {

        item_tree = proto_tree_add_subtree_format(dlt_tree, tvb, offset, -1, ett_dlt_item, &ti_item, "DLT Log Line");

        proto_tree_add_item(item_tree, hf_dlt_file_magic, tvb, offset, 4, ENC_ASCII);

        offset += 4;

        uint32_t tstamp_s = 0;

        proto_tree_add_item_ret_uint(item_tree, hf_dlt_file_tstamp_s, tvb, offset, 4, ENC_LITTLE_ENDIAN, &tstamp_s);

        offset += 4;

        uint32_t tstamp_us = 0;

        proto_tree_add_item_ret_uint(item_tree, hf_dlt_file_tstamp_us, tvb, offset, 4, ENC_LITTLE_ENDIAN, &tstamp_us);

        offset += 4;

        const uint8_t *ecuid;

        proto_tree_add_item_ret_string(item_tree, hf_dlt_file_ecuid, tvb, offset, 4, ENC_ASCII | ENC_NA, pinfo->pool, &ecuid);

        offset += 4;

        proto_tree_add_item(item_tree, hf_dlt_file_header_type, tvb, offset, 1, ENC_NA);

        offset += 1;

        unsigned counter = 0;

        proto_tree_add_item_ret_uint(item_tree, hf_dlt_file_message_counter, tvb, offset, 1, ENC_NA, &counter);

        offset += 1;

        proto_tree_add_item_ret_uint(item_tree, hf_dlt_file_length, tvb, offset, 2, ENC_BIG_ENDIAN, &len);

        offset += 2;

        proto_tree_add_item(item_tree, hf_dlt_file_data, tvb, offset, len - 4, ENC_NA);

        offset += (len - 4);

        proto_item_set_end(ti_item, tvb, offset);

        proto_item_append_text(ti_item, " %3u %u.%06u ECU:%s Len:%u", counter, tstamp_s, tstamp_us, ecuid, len);

    }

    return offset;

}

static bool

dissect_dlt_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data) {

    return dissect_dlt(tvb, pinfo, tree, data) > 0;

}

void

proto_register_file_dlt(void) {

    static hf_register_info hf[] = {

        { &hf_dlt_file_magic,

            { "Magic", "file-dlt.magic", FT_STRING, BASE_NONE, NULL, 0x00, NULL, HFILL }},

        { &hf_dlt_file_tstamp_s,

            { "Timestamp s", "file-dlt.timestamp_s", FT_UINT32, BASE_DEC, NULL, 0x00, NULL, HFILL }},

        { &hf_dlt_file_tstamp_us,

            { "Timestamp us", "file-dlt.timestamp_us", FT_UINT32, BASE_DEC, NULL, 0x00, NULL, HFILL }},

        { &hf_dlt_file_ecuid,

            { "ECU ID", "file-dlt.ecu_id", FT_STRING, BASE_NONE, NULL, 0x00, NULL, HFILL }},

        { &hf_dlt_file_header_type,

            { "Header Type", "file-dlt.header_type", FT_UINT8, BASE_HEX, NULL, 0x00, NULL, HFILL }},

        { &hf_dlt_file_message_counter,

            { "Message Counter", "file-dlt.msg_counter", FT_UINT8, BASE_DEC, NULL, 0x00, NULL, HFILL }},

        { &hf_dlt_file_length,

            { "Length", "file-dlt.length", FT_UINT16, BASE_DEC, NULL, 0x00, NULL, HFILL }},

        { &hf_dlt_file_data,

            { "Data", "file-dlt.data", FT_BYTES, BASE_NONE, NULL, 0x00, NULL, HFILL }},

    };

    static int *ett[] = {

        &ett_dlt,

        &ett_dlt_item,

    };

    proto_dlt = proto_register_protocol("DLT File Format", "File-DLT", "file-dlt");

    proto_register_field_array(proto_dlt, hf, array_length(hf));

    proto_register_subtree_array(ett, array_length(ett));

    register_dissector("file-dlt", dissect_dlt, proto_dlt);

}

void

proto_reg_handoff_file_dlt(void) {

    heur_dissector_add("wtap_file", dissect_dlt_heur, "DLT File", "dlt_wtap", proto_dlt, HEURISTIC_ENABLE);

}

/*

 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html

 *

 * Local variables:

 * c-basic-offset: 4

 * tab-width: 8

 * indent-tabs-mode: nil

 * End:

 *

 * vi: set shiftwidth=4 tabstop=8 expandtab:

 * :indentSize=4:tabSize=8:noTabs=true:

 */