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wireshark/epan/dissectors/packet-mpeg-sect.c

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/* 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
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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 along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/prefs.h>
#include <epan/crc32-tvb.h>
#include <epan/expert.h>
#include "packet-mpeg-sect.h"
void proto_register_mpeg_sect(void);
static int proto_mpeg_sect = -1;
static int hf_mpeg_sect_table_id = -1;
static int hf_mpeg_sect_syntax_indicator = -1;
static int hf_mpeg_sect_reserved = -1;
static int hf_mpeg_sect_length = -1;
static int hf_mpeg_sect_crc = -1;
static int hf_mpeg_sect_crc_status = -1;
static gint ett_mpeg_sect = -1;
static expert_field ei_mpeg_sect_crc = EI_INIT;
static dissector_table_t mpeg_sect_tid_dissector_table;
static gboolean mpeg_sect_check_crc = FALSE;
/* 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 = 0x4E,
TID_EIT_OTHER,
TID_TDT = 0x70,
TID_RST,
TID_ST,
TID_TOT
};
/* 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, "Event Information Table (EIT), actual TS" },
{ TID_EIT_OTHER, "Event Information Table (EIT), 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_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 }
};
/* 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 */
gint
packet_mpeg_sect_mjd_to_utc_time(tvbuff_t *tvb, gint offset, nstime_t *utc_time)
{
gint bcd_time_offset; /* start offset of the bcd time in the tvbuff */
guint8 hour, min, sec;
if (!utc_time)
return -1;
nstime_set_zero(utc_time);
utc_time->secs = (tvb_get_ntohs(tvb, offset) - 40587) * 86400;
bcd_time_offset = offset+2;
hour = MPEG_SECT_BCD44_TO_DEC(tvb_get_guint8(tvb, bcd_time_offset));
min = MPEG_SECT_BCD44_TO_DEC(tvb_get_guint8(tvb, bcd_time_offset+1));
sec = MPEG_SECT_BCD44_TO_DEC(tvb_get_guint8(tvb, bcd_time_offset+2));
if (hour>23 || min>59 || sec>59)
return -1;
utc_time->secs += hour*3600 + min*60 + sec;
return 5;
}
guint
packet_mpeg_sect_header(tvbuff_t *tvb, guint offset,
proto_tree *tree, guint *sect_len, gboolean *ssi)
{
return packet_mpeg_sect_header_extra(tvb, offset, tree, sect_len,
NULL, ssi, NULL);
}
guint
packet_mpeg_sect_header_extra(tvbuff_t *tvb, guint offset, proto_tree *tree,
guint *sect_len, guint *reserved, gboolean *ssi,
proto_item **items)
{
guint tmp;
guint len = 0;
proto_item *pi[PACKET_MPEG_SECT_PI__SIZE];
gint 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;
}
guint
packet_mpeg_sect_crc(tvbuff_t *tvb, packet_info *pinfo,
proto_tree *tree, guint start, guint 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_)
{
gint tvb_len;
gint offset = 0;
guint section_length = 0;
gboolean syntax_indicator = FALSE;
guint8 table_id;
proto_item *ti;
proto_tree *mpeg_sect_tree;
/* the incoming tvb contains only one section, no additional data */
tvb_len = (gint)tvb_reported_length(tvb);
if (tvb_len<MPEG_SECT_MIN_LEN || tvb_len>MPEG_SECT_MAX_LEN)
return 0;
table_id = tvb_get_guint8(tvb, offset);
/* 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 gint *ett[] = {
&ett_mpeg_sect
};
static ei_register_info ei[] = {
{ &ei_mpeg_sect_crc, { "mpeg_sect.crc.invalid", PI_CHECKSUM, PI_WARN, "Invalid CRC", EXPFILL }},
};
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, DISSECTOR_TABLE_NOT_ALLOW_DUPLICATE);
}
/*
* Editor modelines - http://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:
*/
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