/* packet-mpeg-sect.c

 * Routines for MPEG2 (ISO/ISO 13818-1) Section dissection

 * Copyright 2012, Guy Martin <gmsoft@tuxicoman.be>

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998 Gerald Combs

 *

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

 */

#include "config.h"

#include "jtckdint.h"

#include <epan/packet.h>

#include <epan/prefs.h>

#include <epan/crc32-tvb.h>

#include <epan/expert.h>

#include <epan/decode_as.h>

#include <epan/proto_data.h>

#include "packet-mpeg-sect.h"

void proto_register_mpeg_sect(void);

static int proto_mpeg_sect;

static int hf_mpeg_sect_table_id;

static int hf_mpeg_sect_syntax_indicator;

static int hf_mpeg_sect_reserved;

static int hf_mpeg_sect_length;

static int hf_mpeg_sect_crc;

static int hf_mpeg_sect_crc_status;

static int ett_mpeg_sect;

static expert_field ei_mpeg_sect_crc;

static dissector_table_t mpeg_sect_tid_dissector_table;

static bool mpeg_sect_check_crc;

/* minimum length of the entire section ==

   bytes from table_id to section_length == 3 bytes */

#define MPEG_SECT_MIN_LEN    3

/* the section_length field is 12 bits, it can add up to 4096 bytes

   after the initial bytes */

#define MPEG_SECT_MAX_LEN    MPEG_SECT_MIN_LEN+4096

#define MPEG_SECT_SYNTAX_INDICATOR_MASK 0x8000

#define MPEG_SECT_RESERVED_MASK         0x7000

#define MPEG_SECT_LENGTH_MASK           0x0FFF

/* From ISO/IEC 13818-1 */

enum {

    TID_PAT,

    TID_CA,

    TID_PMT,

    TID_TS_DESC,

    TID_SCENE_DESC,

    TID_OBJECT_DESC,

    TID_FORBIDEN    = 0xFF

};

/* From ETSI EN 300 468 */

enum {

    TID_NIT       = 0x40,

    TID_NIT_OTHER,

    TID_SDT,

    TID_SDT_OTHER = 0x46,

    TID_BAT       = 0x4A,

    TID_EIT_PF    = 0x4E,

    TID_EIT_PF_OTHER,

    TID_EIT_SC0   = 0x50,

    TID_EIT_SC1,

    TID_EIT_SC2,

    TID_EIT_SC3,

    TID_EIT_SC4,

    TID_EIT_SC5,

    TID_EIT_SC6,

    TID_EIT_SC7,

    TID_EIT_SC8,

    TID_EIT_SC9,

    TID_EIT_SCA,

    TID_EIT_SCB,

    TID_EIT_SCC,

    TID_EIT_SCD,

    TID_EIT_SCE,

    TID_EIT_SCF,

    TID_EIT_SC0_OTH = 0x60,

    TID_EIT_SC1_OTH,

    TID_EIT_SC2_OTH,

    TID_EIT_SC3_OTH,

    TID_EIT_SC4_OTH,

    TID_EIT_SC5_OTH,

    TID_EIT_SC6_OTH,

    TID_EIT_SC7_OTH,

    TID_EIT_SC8_OTH,

    TID_EIT_SC9_OTH,

    TID_EIT_SCA_OTH,

    TID_EIT_SCB_OTH,

    TID_EIT_SCC_OTH,

    TID_EIT_SCD_OTH,

    TID_EIT_SCE_OTH,

    TID_EIT_SCF_OTH,

    TID_TDT       = 0x70,

    TID_RST,

    TID_ST,

    TID_TOT,

    TID_SIT       = 0x7F

};

/* From ETSI EN 301 790 */

enum {

    TID_RMT = 0x41, /* Conflict with TID_NIT_OTHER */

    TID_SCT = 0xA0,

    TID_FCT,

    TID_TCT,

    TID_SPT,

    TID_CMT,

    TID_TBTP,

    TID_PCR,

    TID_TIM = 0xB0

};

/* From ETSI EN 301 192 */

enum {

    TID_DVB_MPE = 0x3E

};

/* From OC-SP-ETV-AM 1.0-IO5 */

enum {

    TID_ETV_EISS = 0xE0,

    TID_ETV_DII  = 0xE3,

    TID_ETV_DDB  = 0xE4

};

/* From ETSI TS 102 899 */

enum {

    TID_AIT = 0x74

};

static const value_string mpeg_sect_table_id_vals[] = {

    { TID_PAT,         "Program Association Table (PAT)" },

    { TID_CA,          "Conditional Access (CA)" },

    { TID_PMT,         "Program Map Table (PMT)" },

    { TID_TS_DESC,     "Transport Stream Description" },

    { TID_SCENE_DESC,  "ISO/IEC 14496 Scene Description" },

    { TID_OBJECT_DESC, "ISO/IEC 14496 Object Description" },

    { TID_NIT,         "Network Information Table (NIT), current network" },

    { TID_NIT_OTHER,   "Network Information Table (NIT), other network" },

    { TID_SDT,         "Service Description Table (SDT), current network" },

    { TID_SDT_OTHER,   "Service Description (SDT), other network" },

    { TID_BAT,         "Bouquet Association Table (BAT)" },

    { TID_EIT_PF,      "Event Information Table (EIT), present/following, actual TS" },

    { TID_EIT_PF_OTHER,"Event Information Table (EIT), present/following, other TS" },

    { TID_EIT_SC0,     "Event Information Table (EIT), schedule 0, actual TS" },

    { TID_EIT_SC1,     "Event Information Table (EIT), schedule 1, actual TS" },

    { TID_EIT_SC2,     "Event Information Table (EIT), schedule 2, actual TS" },

    { TID_EIT_SC3,     "Event Information Table (EIT), schedule 3, actual TS" },

    { TID_EIT_SC4,     "Event Information Table (EIT), schedule 4, actual TS" },

    { TID_EIT_SC5,     "Event Information Table (EIT), schedule 5, actual TS" },

    { TID_EIT_SC6,     "Event Information Table (EIT), schedule 6, actual TS" },

    { TID_EIT_SC7,     "Event Information Table (EIT), schedule 7, actual TS" },

    { TID_EIT_SC8,     "Event Information Table (EIT), schedule 8, actual TS" },

    { TID_EIT_SC9,     "Event Information Table (EIT), schedule 9, actual TS" },

    { TID_EIT_SCA,     "Event Information Table (EIT), schedule A, actual TS" },

    { TID_EIT_SCB,     "Event Information Table (EIT), schedule B, actual TS" },

    { TID_EIT_SCC,     "Event Information Table (EIT), schedule C, actual TS" },

    { TID_EIT_SCD,     "Event Information Table (EIT), schedule D, actual TS" },

    { TID_EIT_SCE,     "Event Information Table (EIT), schedule E, actual TS" },

    { TID_EIT_SCF,     "Event Information Table (EIT), schedule F, actual TS" },

    { TID_EIT_SC0_OTH, "Event Information Table (EIT), schedule 0, other TS" },

    { TID_EIT_SC1_OTH, "Event Information Table (EIT), schedule 1, other TS" },

    { TID_EIT_SC2_OTH, "Event Information Table (EIT), schedule 2, other TS" },

    { TID_EIT_SC3_OTH, "Event Information Table (EIT), schedule 3, other TS" },

    { TID_EIT_SC4_OTH, "Event Information Table (EIT), schedule 4, other TS" },

    { TID_EIT_SC5_OTH, "Event Information Table (EIT), schedule 5, other TS" },

    { TID_EIT_SC6_OTH, "Event Information Table (EIT), schedule 6, other TS" },

    { TID_EIT_SC7_OTH, "Event Information Table (EIT), schedule 7, other TS" },

    { TID_EIT_SC8_OTH, "Event Information Table (EIT), schedule 8, other TS" },

    { TID_EIT_SC9_OTH, "Event Information Table (EIT), schedule 9, other TS" },

    { TID_EIT_SCA_OTH, "Event Information Table (EIT), schedule A, other TS" },

    { TID_EIT_SCB_OTH, "Event Information Table (EIT), schedule B, other TS" },

    { TID_EIT_SCC_OTH, "Event Information Table (EIT), schedule C, other TS" },

    { TID_EIT_SCD_OTH, "Event Information Table (EIT), schedule D, other TS" },

    { TID_EIT_SCE_OTH, "Event Information Table (EIT), schedule E, other TS" },

    { TID_EIT_SCF_OTH, "Event Information Table (EIT), schedule F, other TS" },

    { TID_TDT,         "Time and Date Table (TDT)" },

    { TID_RST,         "Running Status Table (RST)" },

    { TID_ST,          "Stuffing Table (ST)" },

    { TID_TOT,         "Time Offset Table (TOT)" },

    { TID_AIT,         "Application Information Table (AIT)" },

    { TID_SIT,         "Selection Information Table (SIT)" },

    { TID_SCT,         "Superframe Composition Table (SCT)" },

    { TID_FCT,         "Frame Composition Table (FCT)" },

    { TID_TCT,         "Time-Slot Composition Table (TCT)" },

    { TID_SPT,         "Satellite Position Table (SPT)" },

    { TID_CMT,         "Correction Message Table (CMT)" },

    { TID_TBTP,        "Terminal Burst Time Plan (TBTP)" },

    { TID_TIM,         "Terminal Information Message (TIM)" },

    { TID_DVB_MPE,     "DVB MultiProtocol Encapsulation (MPE)" },

    { TID_ETV_EISS,    "ETV Integrated Signaling Stream (EISS)" },

    { TID_ETV_DII,     "ETV Download Info Indication" },

    { TID_ETV_DDB,     "ETV Download Data Block" },

    { TID_FORBIDEN,    "Forbidden" },

    { 0, NULL }

};

static void mpeg_sect_prompt(packet_info *pinfo, char* result)

{

    snprintf(result, MAX_DECODE_AS_PROMPT_LEN, "Table ID %u as",

        GPOINTER_TO_UINT(p_get_proto_data(pinfo->pool, pinfo, proto_mpeg_sect, MPEG_SECT_TID_KEY)));

}

static void *mpeg_sect_value(packet_info *pinfo)

{

    return p_get_proto_data(pinfo->pool, pinfo, proto_mpeg_sect, MPEG_SECT_TID_KEY);

}

/* read a utc_time field in a tvb and write it to the utc_time struct

   the encoding of the field is according to DVB-SI specification, section 5.2.5

   16bit modified julian day (MJD), 24bit 6*4bit BCD digits hhmmss

   return the length in bytes or -1 for error */

int

packet_mpeg_sect_mjd_to_utc_time(tvbuff_t *tvb, int offset, nstime_t *utc_time)

{

    int    bcd_time_offset;     /* start offset of the bcd time in the tvbuff */

    uint8_t hour, min, sec;

    if (!utc_time)

        return -1;

    nstime_set_zero(utc_time);

    /* The 16-bit MJD epoch is November 17, 1858, which is 40587 days

     * before the UN*X epoch. */

    if (ckd_mul(&utc_time->secs, tvb_get_ntohs(tvb, offset) - 40587, 86400)) {

        /* This can overflow with 32-bit time_t. */

        return -1;

    }

    bcd_time_offset = offset+2;

    hour            = MPEG_SECT_BCD44_TO_DEC(tvb_get_uint8(tvb, bcd_time_offset));

    min             = MPEG_SECT_BCD44_TO_DEC(tvb_get_uint8(tvb, bcd_time_offset+1));

    sec             = MPEG_SECT_BCD44_TO_DEC(tvb_get_uint8(tvb, bcd_time_offset+2));

    if (hour>23 || min>59 || sec>59)

        return -1;

    utc_time->secs += hour*3600 + min*60 + sec;

    return 5;

}

unsigned

packet_mpeg_sect_header(tvbuff_t *tvb, unsigned offset,

            proto_tree *tree, unsigned *sect_len, bool *ssi)

{

    return packet_mpeg_sect_header_extra(tvb, offset, tree, sect_len,

                         NULL, ssi, NULL);

}

unsigned

packet_mpeg_sect_header_extra(tvbuff_t *tvb, unsigned offset, proto_tree *tree,

                unsigned *sect_len, unsigned *reserved, bool *ssi,

                proto_item **items)

{

    unsigned    tmp;

    unsigned    len = 0;

    proto_item *pi[PACKET_MPEG_SECT_PI__SIZE];

    int         i;

    for (i = 0; i < PACKET_MPEG_SECT_PI__SIZE; i++) {

        pi[i] = NULL;

    }

    if (tree) {

        pi[PACKET_MPEG_SECT_PI__TABLE_ID] =

            proto_tree_add_item(tree, hf_mpeg_sect_table_id,

                    tvb, offset + len, 1, ENC_BIG_ENDIAN);

    }

    len++;

    if (tree) {

        pi[PACKET_MPEG_SECT_PI__SSI] =

            proto_tree_add_item(tree, hf_mpeg_sect_syntax_indicator,

                    tvb, offset + len, 2, ENC_BIG_ENDIAN);

        pi[PACKET_MPEG_SECT_PI__RESERVED] =

            proto_tree_add_item(tree, hf_mpeg_sect_reserved, tvb,

                    offset + len, 2, ENC_BIG_ENDIAN);

        pi[PACKET_MPEG_SECT_PI__LENGTH] =

            proto_tree_add_item(tree, hf_mpeg_sect_length, tvb,

                    offset + len, 2, ENC_BIG_ENDIAN);

    }

    tmp = tvb_get_ntohs(tvb, offset + len);

    if (sect_len)

        *sect_len = MPEG_SECT_LENGTH_MASK & tmp;

    if (reserved)

        *reserved = (MPEG_SECT_RESERVED_MASK & tmp) >> 12;

    if (ssi)

        *ssi = (MPEG_SECT_SYNTAX_INDICATOR_MASK & tmp);

    if (items) {

        for (i = 0; i < PACKET_MPEG_SECT_PI__SIZE; i++) {

            items[i] = pi[i];

        }

    }

    len += 2;

    return len;

}

unsigned

packet_mpeg_sect_crc(tvbuff_t *tvb, packet_info *pinfo,

             proto_tree *tree, unsigned start, unsigned end)

{

    if (mpeg_sect_check_crc) {

        proto_tree_add_checksum(tree, tvb, end, hf_mpeg_sect_crc, hf_mpeg_sect_crc_status, &ei_mpeg_sect_crc, pinfo, crc32_mpeg2_tvb_offset(tvb, start, end),

                                ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);

    } else {

        proto_tree_add_checksum(tree, tvb, end, hf_mpeg_sect_crc, hf_mpeg_sect_crc_status, &ei_mpeg_sect_crc, pinfo, crc32_mpeg2_tvb_offset(tvb, start, end),

                                ENC_BIG_ENDIAN, PROTO_CHECKSUM_NO_FLAGS);

    }

    return 4;

}

static int

dissect_mpeg_sect(tvbuff_t *tvb, packet_info *pinfo,

        proto_tree *tree, void *data _U_)

{

    int      tvb_len;

    int      offset           = 0;

    unsigned section_length   = 0;

    bool     syntax_indicator = false;

    uint8_t  table_id;

    proto_item *ti;

    proto_tree *mpeg_sect_tree;

    /* the incoming tvb contains only one section, no additional data */

    tvb_len = (int)tvb_reported_length(tvb);

    if (tvb_len<MPEG_SECT_MIN_LEN || tvb_len>MPEG_SECT_MAX_LEN)

        return 0;

    table_id = tvb_get_uint8(tvb, offset);

    p_add_proto_data(pinfo->pool, pinfo, proto_mpeg_sect, MPEG_SECT_TID_KEY, GUINT_TO_POINTER(table_id));

    /* Check if a dissector can parse the current table */

    if (dissector_try_uint(mpeg_sect_tid_dissector_table, table_id, tvb, pinfo, tree))

        return tvb_len;

    /* If no dissector is registered, use the common one */

    col_set_str(pinfo->cinfo, COL_PROTOCOL, "MPEG SECT");

    col_add_fstr(pinfo->cinfo, COL_INFO, "Table ID 0x%02x", table_id);

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

    mpeg_sect_tree = proto_item_add_subtree(ti, ett_mpeg_sect);

    proto_item_append_text(ti, " Table_ID=0x%02x", table_id);

    packet_mpeg_sect_header(tvb, offset, mpeg_sect_tree,

                &section_length, &syntax_indicator);

    if (syntax_indicator)

        packet_mpeg_sect_crc(tvb, pinfo, mpeg_sect_tree, 0, (section_length-1));

    return tvb_len;

}

void

proto_register_mpeg_sect(void)

{

    static hf_register_info hf[] = {

        { &hf_mpeg_sect_table_id, {

            "Table ID", "mpeg_sect.tid",

            FT_UINT8, BASE_HEX, VALS(mpeg_sect_table_id_vals), 0, NULL, HFILL

        } },

        { &hf_mpeg_sect_syntax_indicator, {

            "Syntax indicator", "mpeg_sect.syntax_indicator",

            FT_UINT16, BASE_DEC, NULL, MPEG_SECT_SYNTAX_INDICATOR_MASK, NULL, HFILL

        } },

        { &hf_mpeg_sect_reserved, {

            "Reserved", "mpeg_sect.reserved",

            FT_UINT16, BASE_HEX, NULL, MPEG_SECT_RESERVED_MASK, NULL, HFILL

        } },

        { &hf_mpeg_sect_length, {

            "Length", "mpeg_sect.len",

            FT_UINT16, BASE_DEC, NULL, MPEG_SECT_LENGTH_MASK, NULL, HFILL

        } },

        { &hf_mpeg_sect_crc, {

            "CRC 32", "mpeg_sect.crc",

            FT_UINT32, BASE_HEX, NULL, 0, NULL, HFILL

        } },

        { &hf_mpeg_sect_crc_status, {

            "CRC 32 Status", "mpeg_sect.crc.status",

            FT_UINT8, BASE_NONE, VALS(proto_checksum_vals), 0, NULL, HFILL

        } },

    };

    static int *ett[] = {

        &ett_mpeg_sect

    };

    static ei_register_info ei[] = {

        { &ei_mpeg_sect_crc, { "mpeg_sect.crc.invalid", PI_CHECKSUM, PI_WARN, "Invalid CRC", EXPFILL }},

    };

    /* Decode As handling */

    static build_valid_func mpeg_sect_da_build_value[1] = {mpeg_sect_value};

    static decode_as_value_t mpeg_sect_da_values = {mpeg_sect_prompt, 1, mpeg_sect_da_build_value};

    static decode_as_t mpeg_sect_da = {"mpeg_sect", "mpeg_sect.tid", 1, 0, &mpeg_sect_da_values, NULL, NULL, decode_as_default_populate_list, decode_as_default_reset, decode_as_default_change, NULL, NULL, NULL };

    module_t *mpeg_sect_module;

    expert_module_t* expert_mpeg_sect;

    proto_mpeg_sect = proto_register_protocol("MPEG2 Section", "MPEG SECT", "mpeg_sect");

    register_dissector("mpeg_sect", dissect_mpeg_sect, proto_mpeg_sect);

    proto_register_field_array(proto_mpeg_sect, hf, array_length(hf));

    proto_register_subtree_array(ett, array_length(ett));

    expert_mpeg_sect = expert_register_protocol(proto_mpeg_sect);

    expert_register_field_array(expert_mpeg_sect, ei, array_length(ei));

    mpeg_sect_module = prefs_register_protocol(proto_mpeg_sect, NULL);

    prefs_register_bool_preference(mpeg_sect_module,

        "verify_crc",

        "Verify the section CRC",

        "Whether the section dissector should verify the CRC",

        &mpeg_sect_check_crc);

    mpeg_sect_tid_dissector_table = register_dissector_table("mpeg_sect.tid",

                                 "MPEG SECT Table ID",

                                 proto_mpeg_sect, FT_UINT8, BASE_HEX);

    register_decode_as(&mpeg_sect_da);

}

/*

 * 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:

 */