epan/dissectors/packet-mpeg-sect.c

   1 /* packet-mpeg-sect.c
   2  * Routines for MPEG2 (ISO/ISO 13818-1) Section dissection
   3  * Copyright 2012, Guy Martin <gmsoft@tuxicoman.be>
   4  *
   5  * Wireshark - Network traffic analyzer
   6  * By Gerald Combs <gerald@wireshark.org>
   7  * Copyright 1998 Gerald Combs
   8  *
   9  * SPDX-License-Identifier: GPL-2.0-or-later
  10  */
  11
  12 #include "config.h"
  13
  14 #include <epan/packet.h>
  15 #include <epan/prefs.h>
  16 #include <epan/crc32-tvb.h>
  17 #include <epan/expert.h>
  18 #include <epan/decode_as.h>
  19 #include <epan/proto_data.h>
  20 #include "packet-mpeg-sect.h"
  21
  22 void proto_register_mpeg_sect(void);
  23
  24 static int proto_mpeg_sect;
  25 static int hf_mpeg_sect_table_id;
  26 static int hf_mpeg_sect_syntax_indicator;
  27 static int hf_mpeg_sect_reserved;
  28 static int hf_mpeg_sect_length;
  29 static int hf_mpeg_sect_crc;
  30 static int hf_mpeg_sect_crc_status;
  31
  32 static int ett_mpeg_sect;
  33
  34 static expert_field ei_mpeg_sect_crc;
  35
  36 static dissector_table_t mpeg_sect_tid_dissector_table;
  37
  38 static bool mpeg_sect_check_crc;
  39
  40 /* minimum length of the entire section ==
  41    bytes from table_id to section_length == 3 bytes */
  42 #define MPEG_SECT_MIN_LEN    3
  43 /* the section_length field is 12 bits, it can add up to 4096 bytes
  44    after the initial bytes */
  45 #define MPEG_SECT_MAX_LEN    MPEG_SECT_MIN_LEN+4096
  46
  47
  48 #define MPEG_SECT_SYNTAX_INDICATOR_MASK 0x8000
  49 #define MPEG_SECT_RESERVED_MASK         0x7000
  50 #define MPEG_SECT_LENGTH_MASK           0x0FFF
  51
  52 /* From ISO/IEC 13818-1 */
  53 enum {
  54     TID_PAT,
  55     TID_CA,
  56     TID_PMT,
  57     TID_TS_DESC,
  58     TID_SCENE_DESC,
  59     TID_OBJECT_DESC,
  60     TID_FORBIDEN    = 0xFF
  61 };
  62
  63 /* From ETSI EN 300 468 */
  64 enum {
  65     TID_NIT       = 0x40,
  66     TID_NIT_OTHER,
  67     TID_SDT,
  68     TID_SDT_OTHER = 0x46,
  69     TID_BAT       = 0x4A,
  70     TID_EIT_PF    = 0x4E,
  71     TID_EIT_PF_OTHER,
  72     TID_EIT_SC0   = 0x50,
  73     TID_EIT_SC1,
  74     TID_EIT_SC2,
  75     TID_EIT_SC3,
  76     TID_EIT_SC4,
  77     TID_EIT_SC5,
  78     TID_EIT_SC6,
  79     TID_EIT_SC7,
  80     TID_EIT_SC8,
  81     TID_EIT_SC9,
  82     TID_EIT_SCA,
  83     TID_EIT_SCB,
  84     TID_EIT_SCC,
  85     TID_EIT_SCD,
  86     TID_EIT_SCE,
  87     TID_EIT_SCF,
  88     TID_EIT_SC0_OTH = 0x60,
  89     TID_EIT_SC1_OTH,
  90     TID_EIT_SC2_OTH,
  91     TID_EIT_SC3_OTH,
  92     TID_EIT_SC4_OTH,
  93     TID_EIT_SC5_OTH,
  94     TID_EIT_SC6_OTH,
  95     TID_EIT_SC7_OTH,
  96     TID_EIT_SC8_OTH,
  97     TID_EIT_SC9_OTH,
  98     TID_EIT_SCA_OTH,
  99     TID_EIT_SCB_OTH,
 100     TID_EIT_SCC_OTH,
 101     TID_EIT_SCD_OTH,
 102     TID_EIT_SCE_OTH,
 103     TID_EIT_SCF_OTH,
 104     TID_TDT       = 0x70,
 105     TID_RST,
 106     TID_ST,
 107     TID_TOT,
 108     TID_SIT       = 0x7F
 109 };
 110
 111 /* From ETSI EN 301 790 */
 112 enum {
 113     TID_RMT = 0x41, /* Conflict with TID_NIT_OTHER */
 114     TID_SCT = 0xA0,
 115     TID_FCT,
 116     TID_TCT,
 117     TID_SPT,
 118     TID_CMT,
 119     TID_TBTP,
 120     TID_PCR,
 121     TID_TIM = 0xB0
 122 };
 123
 124 /* From ETSI EN 301 192 */
 125 enum {
 126     TID_DVB_MPE = 0x3E
 127 };
 128
 129 /* From OC-SP-ETV-AM 1.0-IO5 */
 130 enum {
 131     TID_ETV_EISS = 0xE0,
 132     TID_ETV_DII  = 0xE3,
 133     TID_ETV_DDB  = 0xE4
 134 };
 135
 136 /* From ETSI TS 102 899 */
 137 enum {
 138     TID_AIT = 0x74
 139 };
 140
 141
 142 static const value_string mpeg_sect_table_id_vals[] = {
 143
 144     { TID_PAT,         "Program Association Table (PAT)" },
 145     { TID_CA,          "Conditional Access (CA)" },
 146     { TID_PMT,         "Program Map Table (PMT)" },
 147     { TID_TS_DESC,     "Transport Stream Description" },
 148     { TID_SCENE_DESC,  "ISO/IEC 14496 Scene Description" },
 149     { TID_OBJECT_DESC, "ISO/IEC 14496 Object Description" },
 150     { TID_NIT,         "Network Information Table (NIT), current network" },
 151     { TID_NIT_OTHER,   "Network Information Table (NIT), other network" },
 152     { TID_SDT,         "Service Description Table (SDT), current network" },
 153     { TID_SDT_OTHER,   "Service Description (SDT), other network" },
 154     { TID_BAT,         "Bouquet Association Table (BAT)" },
 155     { TID_EIT_PF,      "Event Information Table (EIT), present/following, actual TS" },
 156     { TID_EIT_PF_OTHER,"Event Information Table (EIT), present/following, other TS" },
 157     { TID_EIT_SC0,     "Event Information Table (EIT), schedule 0, actual TS" },
 158     { TID_EIT_SC1,     "Event Information Table (EIT), schedule 1, actual TS" },
 159     { TID_EIT_SC2,     "Event Information Table (EIT), schedule 2, actual TS" },
 160     { TID_EIT_SC3,     "Event Information Table (EIT), schedule 3, actual TS" },
 161     { TID_EIT_SC4,     "Event Information Table (EIT), schedule 4, actual TS" },
 162     { TID_EIT_SC5,     "Event Information Table (EIT), schedule 5, actual TS" },
 163     { TID_EIT_SC6,     "Event Information Table (EIT), schedule 6, actual TS" },
 164     { TID_EIT_SC7,     "Event Information Table (EIT), schedule 7, actual TS" },
 165     { TID_EIT_SC8,     "Event Information Table (EIT), schedule 8, actual TS" },
 166     { TID_EIT_SC9,     "Event Information Table (EIT), schedule 9, actual TS" },
 167     { TID_EIT_SCA,     "Event Information Table (EIT), schedule A, actual TS" },
 168     { TID_EIT_SCB,     "Event Information Table (EIT), schedule B, actual TS" },
 169     { TID_EIT_SCC,     "Event Information Table (EIT), schedule C, actual TS" },
 170     { TID_EIT_SCD,     "Event Information Table (EIT), schedule D, actual TS" },
 171     { TID_EIT_SCE,     "Event Information Table (EIT), schedule E, actual TS" },
 172     { TID_EIT_SCF,     "Event Information Table (EIT), schedule F, actual TS" },
 173     { TID_EIT_SC0_OTH, "Event Information Table (EIT), schedule 0, other TS" },
 174     { TID_EIT_SC1_OTH, "Event Information Table (EIT), schedule 1, other TS" },
 175     { TID_EIT_SC2_OTH, "Event Information Table (EIT), schedule 2, other TS" },
 176     { TID_EIT_SC3_OTH, "Event Information Table (EIT), schedule 3, other TS" },
 177     { TID_EIT_SC4_OTH, "Event Information Table (EIT), schedule 4, other TS" },
 178     { TID_EIT_SC5_OTH, "Event Information Table (EIT), schedule 5, other TS" },
 179     { TID_EIT_SC6_OTH, "Event Information Table (EIT), schedule 6, other TS" },
 180     { TID_EIT_SC7_OTH, "Event Information Table (EIT), schedule 7, other TS" },
 181     { TID_EIT_SC8_OTH, "Event Information Table (EIT), schedule 8, other TS" },
 182     { TID_EIT_SC9_OTH, "Event Information Table (EIT), schedule 9, other TS" },
 183     { TID_EIT_SCA_OTH, "Event Information Table (EIT), schedule A, other TS" },
 184     { TID_EIT_SCB_OTH, "Event Information Table (EIT), schedule B, other TS" },
 185     { TID_EIT_SCC_OTH, "Event Information Table (EIT), schedule C, other TS" },
 186     { TID_EIT_SCD_OTH, "Event Information Table (EIT), schedule D, other TS" },
 187     { TID_EIT_SCE_OTH, "Event Information Table (EIT), schedule E, other TS" },
 188     { TID_EIT_SCF_OTH, "Event Information Table (EIT), schedule F, other TS" },
 189     { TID_TDT,         "Time and Date Table (TDT)" },
 190     { TID_RST,         "Running Status Table (RST)" },
 191     { TID_ST,          "Stuffing Table (ST)" },
 192     { TID_TOT,         "Time Offset Table (TOT)" },
 193     { TID_AIT,         "Application Information Table (AIT)" },
 194     { TID_SIT,         "Selection Information Table (SIT)" },
 195     { TID_SCT,         "Superframe Composition Table (SCT)" },
 196     { TID_FCT,         "Frame Composition Table (FCT)" },
 197     { TID_TCT,         "Time-Slot Composition Table (TCT)" },
 198     { TID_SPT,         "Satellite Position Table (SPT)" },
 199     { TID_CMT,         "Correction Message Table (CMT)" },
 200     { TID_TBTP,        "Terminal Burst Time Plan (TBTP)" },
 201     { TID_TIM,         "Terminal Information Message (TIM)" },
 202     { TID_DVB_MPE,     "DVB MultiProtocol Encapsulation (MPE)" },
 203     { TID_ETV_EISS,    "ETV Integrated Signaling Stream (EISS)" },
 204     { TID_ETV_DII,     "ETV Download Info Indication" },
 205     { TID_ETV_DDB,     "ETV Download Data Block" },
 206     { TID_FORBIDEN,    "Forbidden" },
 207     { 0, NULL }
 208 };
 209
 210 static void mpeg_sect_prompt(packet_info *pinfo, char* result)
 211 {
 212     snprintf(result, MAX_DECODE_AS_PROMPT_LEN, "Table ID %u as",
 213         GPOINTER_TO_UINT(p_get_proto_data(pinfo->pool, pinfo, proto_mpeg_sect, MPEG_SECT_TID_KEY)));
 214 }
 215
 216 static void *mpeg_sect_value(packet_info *pinfo)
 217 {
 218     return p_get_proto_data(pinfo->pool, pinfo, proto_mpeg_sect, MPEG_SECT_TID_KEY);
 219 }
 220
 221 /* read a utc_time field in a tvb and write it to the utc_time struct
 222    the encoding of the field is according to DVB-SI specification, section 5.2.5
 223    16bit modified julian day (MJD), 24bit 6*4bit BCD digits hhmmss
 224    return the length in bytes or -1 for error */
 225 int
 226 packet_mpeg_sect_mjd_to_utc_time(tvbuff_t *tvb, int offset, nstime_t *utc_time)
 227 {
 228     int    bcd_time_offset;     /* start offset of the bcd time in the tvbuff */
 229     uint8_t hour, min, sec;
 230
 231     if (!utc_time)
 232         return -1;
 233
 234     nstime_set_zero(utc_time);
 235     utc_time->secs  = (tvb_get_ntohs(tvb, offset) - 40587) * 86400;
 236     bcd_time_offset = offset+2;
 237     hour            = MPEG_SECT_BCD44_TO_DEC(tvb_get_uint8(tvb, bcd_time_offset));
 238     min             = MPEG_SECT_BCD44_TO_DEC(tvb_get_uint8(tvb, bcd_time_offset+1));
 239     sec             = MPEG_SECT_BCD44_TO_DEC(tvb_get_uint8(tvb, bcd_time_offset+2));
 240     if (hour>23 || min>59 || sec>59)
 241         return -1;
 242
 243     utc_time->secs += hour*3600 + min*60 + sec;
 244     return 5;
 245 }
 246
 247 unsigned
 248 packet_mpeg_sect_header(tvbuff_t *tvb, unsigned offset,
 249             proto_tree *tree, unsigned *sect_len, bool *ssi)
 250 {
 251     return packet_mpeg_sect_header_extra(tvb, offset, tree, sect_len,
 252                          NULL, ssi, NULL);
 253 }
 254
 255 unsigned
 256 packet_mpeg_sect_header_extra(tvbuff_t *tvb, unsigned offset, proto_tree *tree,
 257                 unsigned *sect_len, unsigned *reserved, bool *ssi,
 258                 proto_item **items)
 259 {
 260     unsigned    tmp;
 261     unsigned    len = 0;
 262     proto_item *pi[PACKET_MPEG_SECT_PI__SIZE];
 263     int         i;
 264
 265     for (i = 0; i < PACKET_MPEG_SECT_PI__SIZE; i++) {
 266         pi[i] = NULL;
 267     }
 268
 269     if (tree) {
 270         pi[PACKET_MPEG_SECT_PI__TABLE_ID] =
 271             proto_tree_add_item(tree, hf_mpeg_sect_table_id,
 272                     tvb, offset + len, 1, ENC_BIG_ENDIAN);
 273     }
 274
 275     len++;
 276
 277     if (tree) {
 278         pi[PACKET_MPEG_SECT_PI__SSI] =
 279             proto_tree_add_item(tree, hf_mpeg_sect_syntax_indicator,
 280                     tvb, offset + len, 2, ENC_BIG_ENDIAN);
 281
 282         pi[PACKET_MPEG_SECT_PI__RESERVED] =
 283             proto_tree_add_item(tree, hf_mpeg_sect_reserved, tvb,
 284                     offset + len, 2, ENC_BIG_ENDIAN);
 285
 286         pi[PACKET_MPEG_SECT_PI__LENGTH] =
 287             proto_tree_add_item(tree, hf_mpeg_sect_length, tvb,
 288                     offset + len, 2, ENC_BIG_ENDIAN);
 289     }
 290
 291     tmp = tvb_get_ntohs(tvb, offset + len);
 292
 293     if (sect_len)
 294         *sect_len = MPEG_SECT_LENGTH_MASK & tmp;
 295
 296     if (reserved)
 297         *reserved = (MPEG_SECT_RESERVED_MASK & tmp) >> 12;
 298
 299     if (ssi)
 300         *ssi = (MPEG_SECT_SYNTAX_INDICATOR_MASK & tmp);
 301
 302     if (items) {
 303         for (i = 0; i < PACKET_MPEG_SECT_PI__SIZE; i++) {
 304             items[i] = pi[i];
 305         }
 306     }
 307
 308     len += 2;
 309
 310     return len;
 311 }
 312
 313
 314 unsigned
 315 packet_mpeg_sect_crc(tvbuff_t *tvb, packet_info *pinfo,
 316              proto_tree *tree, unsigned start, unsigned end)
 317 {
 318     if (mpeg_sect_check_crc) {
 319         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),
 320                                 ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
 321     } else {
 322         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),
 323                                 ENC_BIG_ENDIAN, PROTO_CHECKSUM_NO_FLAGS);
 324     }
 325
 326     return 4;
 327 }
 328
 329
 330 static int
 331 dissect_mpeg_sect(tvbuff_t *tvb, packet_info *pinfo,
 332         proto_tree *tree, void *data _U_)
 333 {
 334     int      tvb_len;
 335     int      offset           = 0;
 336     unsigned section_length   = 0;
 337     bool     syntax_indicator = false;
 338     uint8_t  table_id;
 339
 340     proto_item *ti;
 341     proto_tree *mpeg_sect_tree;
 342
 343     /* the incoming tvb contains only one section, no additional data */
 344
 345     tvb_len = (int)tvb_reported_length(tvb);
 346     if (tvb_len<MPEG_SECT_MIN_LEN || tvb_len>MPEG_SECT_MAX_LEN)
 347         return 0;
 348
 349     table_id = tvb_get_uint8(tvb, offset);
 350     p_add_proto_data(pinfo->pool, pinfo, proto_mpeg_sect, MPEG_SECT_TID_KEY, GUINT_TO_POINTER(table_id));
 351
 352     /* Check if a dissector can parse the current table */
 353     if (dissector_try_uint(mpeg_sect_tid_dissector_table, table_id, tvb, pinfo, tree))
 354         return tvb_len;
 355
 356     /* If no dissector is registered, use the common one */
 357     col_set_str(pinfo->cinfo, COL_PROTOCOL, "MPEG SECT");
 358     col_add_fstr(pinfo->cinfo, COL_INFO, "Table ID 0x%02x", table_id);
 359
 360     ti = proto_tree_add_item(tree, proto_mpeg_sect, tvb, offset, -1, ENC_NA);
 361     mpeg_sect_tree = proto_item_add_subtree(ti, ett_mpeg_sect);
 362
 363     proto_item_append_text(ti, " Table_ID=0x%02x", table_id);
 364
 365     packet_mpeg_sect_header(tvb, offset, mpeg_sect_tree,
 366                 &section_length, &syntax_indicator);
 367
 368     if (syntax_indicator)
 369         packet_mpeg_sect_crc(tvb, pinfo, mpeg_sect_tree, 0, (section_length-1));
 370
 371     return tvb_len;
 372 }
 373
 374
 375 void
 376 proto_register_mpeg_sect(void)
 377 {
 378     static hf_register_info hf[] = {
 379         { &hf_mpeg_sect_table_id, {
 380             "Table ID", "mpeg_sect.tid",
 381             FT_UINT8, BASE_HEX, VALS(mpeg_sect_table_id_vals), 0, NULL, HFILL
 382         } },
 383
 384         { &hf_mpeg_sect_syntax_indicator, {
 385             "Syntax indicator", "mpeg_sect.syntax_indicator",
 386             FT_UINT16, BASE_DEC, NULL, MPEG_SECT_SYNTAX_INDICATOR_MASK, NULL, HFILL
 387         } },
 388
 389         { &hf_mpeg_sect_reserved, {
 390             "Reserved", "mpeg_sect.reserved",
 391             FT_UINT16, BASE_HEX, NULL, MPEG_SECT_RESERVED_MASK, NULL, HFILL
 392         } },
 393
 394         { &hf_mpeg_sect_length, {
 395             "Length", "mpeg_sect.len",
 396             FT_UINT16, BASE_DEC, NULL, MPEG_SECT_LENGTH_MASK, NULL, HFILL
 397         } },
 398
 399         { &hf_mpeg_sect_crc, {
 400             "CRC 32", "mpeg_sect.crc",
 401             FT_UINT32, BASE_HEX, NULL, 0, NULL, HFILL
 402         } },
 403
 404         { &hf_mpeg_sect_crc_status, {
 405             "CRC 32 Status", "mpeg_sect.crc.status",
 406             FT_UINT8, BASE_NONE, VALS(proto_checksum_vals), 0, NULL, HFILL
 407         } },
 408
 409     };
 410
 411     static int *ett[] = {
 412         &ett_mpeg_sect
 413     };
 414
 415     static ei_register_info ei[] = {
 416         { &ei_mpeg_sect_crc, { "mpeg_sect.crc.invalid", PI_CHECKSUM, PI_WARN, "Invalid CRC", EXPFILL }},
 417     };
 418
 419     /* Decode As handling */
 420     static build_valid_func mpeg_sect_da_build_value[1] = {mpeg_sect_value};
 421     static decode_as_value_t mpeg_sect_da_values = {mpeg_sect_prompt, 1, mpeg_sect_da_build_value};
 422     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};
 423
 424     module_t *mpeg_sect_module;
 425     expert_module_t* expert_mpeg_sect;
 426
 427     proto_mpeg_sect = proto_register_protocol("MPEG2 Section", "MPEG SECT", "mpeg_sect");
 428     register_dissector("mpeg_sect", dissect_mpeg_sect, proto_mpeg_sect);
 429
 430     proto_register_field_array(proto_mpeg_sect, hf, array_length(hf));
 431     proto_register_subtree_array(ett, array_length(ett));
 432     expert_mpeg_sect = expert_register_protocol(proto_mpeg_sect);
 433     expert_register_field_array(expert_mpeg_sect, ei, array_length(ei));
 434
 435     mpeg_sect_module = prefs_register_protocol(proto_mpeg_sect, NULL);
 436
 437     prefs_register_bool_preference(mpeg_sect_module,
 438         "verify_crc",
 439         "Verify the section CRC",
 440         "Whether the section dissector should verify the CRC",
 441         &mpeg_sect_check_crc);
 442
 443     mpeg_sect_tid_dissector_table = register_dissector_table("mpeg_sect.tid",
 444                                  "MPEG SECT Table ID",
 445                                  proto_mpeg_sect, FT_UINT8, BASE_HEX);
 446
 447     register_decode_as(&mpeg_sect_da);
 448 }
 449
 450 /*
 451  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 452  *
 453  * Local variables:
 454  * c-basic-offset: 4
 455  * tab-width: 8
 456  * indent-tabs-mode: nil
 457  * End:
 458  *
 459  * vi: set shiftwidth=4 tabstop=8 expandtab:
 460  * :indentSize=4:tabSize=8:noTabs=true:
 461  */