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gstreamer/sys/dvb/camutils.c
Edward Hervey d049eadd50 camutils: Fix PMT message construction 
The size of the message ended up being bigger than its content.
That cause some CA modules to just hang.
2012-05-23 09:40:33 +02:00

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/*
* camutils.c -
* Copyright (C) 2007 Alessandro Decina
*
* Authors:
* Alessandro Decina <alessandro@nnva.org>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/* FIXME 0.11: suppress warnings for deprecated API such as GStaticRecMutex
* with newer GLib versions (>= 2.31.0) */
#define GLIB_DISABLE_DEPRECATION_WARNINGS
#include <gst/gst.h>
#include <string.h>
#include "cam.h"
#include "camutils.h"
#define GST_CAT_DEFAULT cam_debug_cat
/* From the spec:
* length_field() {
* size_indicator
* if (size_indicator == 0)
* length_value
* else if (size_indicator == 1) {
* length_field_size
* for (i=0; i<length_field_size; i++) {
* length_value_byte
* }
* }
* }
*/
guint8
cam_calc_length_field_size (guint length)
{
guint field_len;
if (length < G_MAXUINT8)
field_len = 1;
else if (length <= G_MAXUINT16)
field_len = 3;
else if (length <= (1 << 24) - 1)
field_len = 4;
else
field_len = 5;
return field_len;
}
/* write a length_field */
guint8
cam_write_length_field (guint8 * buff, guint length)
{
guint8 field_len = cam_calc_length_field_size (length);
if (buff) {
switch (field_len) {
case 1:
buff[0] = length;
break;
case 2:
g_return_val_if_reached (0);
break;
case 3:
buff[0] = TPDU_HEADER_SIZE_INDICATOR | (field_len - 1);
buff[1] = length >> 8;
buff[2] = length & 0xFF;
break;
case 4:
buff[0] = TPDU_HEADER_SIZE_INDICATOR | (field_len - 1);
buff[1] = length >> 16;
buff[2] = (length >> 8) & 0xFF;
buff[3] = length & 0xFF;
break;
case 5:
buff[0] = TPDU_HEADER_SIZE_INDICATOR | (field_len - 1);
buff[1] = length >> 24;
buff[2] = (length >> 16) & 0xFF;
buff[3] = (length >> 8) & 0xFF;
buff[4] = length & 0xFF;
break;
default:
g_return_val_if_reached (0);
}
}
return field_len;
}
/* read a length_field */
guint8
cam_read_length_field (guint8 * buff, guint * length)
{
guint i;
guint field_len;
guint8 len;
if (buff[0] <= G_MAXINT8) {
field_len = 1;
len = buff[0];
} else {
field_len = buff[0] & ~TPDU_HEADER_SIZE_INDICATOR;
if (field_len > 4) {
GST_ERROR ("length_field length exceeds 4 bytes: %d", field_len);
field_len = 0;
len = 0;
} else {
len = 0;
for (i = 0; i < field_len; ++i)
len = (len << 8) | *++buff;
/* count the size indicator byte */
field_len += 1;
}
}
if (length)
*length = len;
return field_len;
}
/*
* ca_pmt () {
* ca_pmt_tag 24 uimsbf
* length_field()
* ca_pmt_list_management 8 uimsbf
* program_number 16 uimsbf
* reserved 2 bslbf
* version_number 5 uimsbf
* current_next_indicator 1 bslbf
* reserved 4 bslbf
* program_info_length 12 uimsbf
* if (program_info_length != 0) {
* ca_pmt_cmd_id at program level 8 uimsbf
* for (i=0; i<n; i++) {
* CA_descriptor() programme level
* }
* }
* for (i=0; i<n; i++) {
* stream_type 8 uimsbf
* reserved 3 bslbf
* elementary_PID elementary stream PID 13 uimsbf
* reserved 4 bslbf
* ES_info_length 12 uimsbf
* if (ES_info_length != 0) {
* ca_pmt_cmd_id at ES level 8 uimsbf
* for (i=0; i<n; i++) {
* CA_descriptor() elementary stream level
* }
* }
* }
* }
*/
static guint
get_ca_descriptors_length (GValueArray * descriptors)
{
guint i;
guint len = 0;
GValue *value;
GString *desc;
if (descriptors != NULL) {
for (i = 0; i < descriptors->n_values; ++i) {
value = g_value_array_get_nth (descriptors, i);
desc = (GString *) g_value_get_boxed (value);
if (desc->str[0] == 0x09)
len += desc->len;
}
}
return len;
}
static guint8 *
write_ca_descriptors (guint8 * body, GValueArray * descriptors)
{
guint i;
GValue *value;
GString *desc;
if (descriptors != NULL) {
for (i = 0; i < descriptors->n_values; ++i) {
value = g_value_array_get_nth (descriptors, i);
desc = (GString *) g_value_get_boxed (value);
if (desc->str[0] == 0x09) {
memcpy (body, desc->str, desc->len);
body += desc->len;
}
}
}
return body;
}
guint8 *
cam_build_ca_pmt (GstStructure * pmt, guint8 list_management, guint8 cmd_id,
guint * size)
{
guint body_size = 0;
guint8 *buffer;
guint8 *body;
GList *lengths = NULL;
guint len = 0;
const GValue *streams;
guint program_number;
guint version_number;
guint i;
const GValue *value;
GstStructure *stream;
GValueArray *program_descriptors = NULL;
GValueArray *stream_descriptors = NULL;
gst_structure_get_uint (pmt, "program-number", &program_number);
gst_structure_get_uint (pmt, "version-number", &version_number);
streams = gst_structure_get_value (pmt, "streams");
value = gst_structure_get_value (pmt, "descriptors");
if (value != NULL) {
program_descriptors = g_value_get_boxed (value);
/* get the length of program level CA_descriptor()s */
len = get_ca_descriptors_length (program_descriptors);
if (len > 0)
/* add one byte for the program level cmd_id */
len += 1;
}
lengths = g_list_append (lengths, GINT_TO_POINTER (len));
body_size += 6 + len;
/* get the length of stream level CA_descriptor()s */
if (streams != NULL) {
for (i = 0; i < gst_value_list_get_size (streams); ++i) {
value = gst_value_list_get_value (streams, i);
stream = g_value_get_boxed (value);
value = gst_structure_get_value (stream, "descriptors");
len = 0;
if (value != NULL) {
stream_descriptors = g_value_get_boxed (value);
len = get_ca_descriptors_length (stream_descriptors);
if (len > 0)
/* one byte for the stream level cmd_id */
len += 1;
}
lengths = g_list_append (lengths, GINT_TO_POINTER (len));
body_size += 5 + len;
}
}
GST_DEBUG ("Body Size %d", body_size);
buffer = g_malloc0 (body_size);
body = buffer;
/* ca_pmt_list_management 8 uimsbf */
*body++ = list_management;
/* program_number 16 uimsbf */
GST_WRITE_UINT16_BE (body, program_number);
body += 2;
/* reserved 2
* version_number 5
* current_next_indicator 1
*/
*body++ = (version_number << 1) | 0x01;
/* Reserved 4
* program_info_length 12
*/
len = GPOINTER_TO_INT (lengths->data);
lengths = g_list_delete_link (lengths, lengths);
GST_WRITE_UINT16_BE (body, len);
body += 2;
if (len != 0) {
*body++ = cmd_id;
body = write_ca_descriptors (body, program_descriptors);
}
for (i = 0; i < gst_value_list_get_size (streams); ++i) {
guint stream_type;
guint stream_pid;
value = gst_value_list_get_value (streams, i);
stream = g_value_get_boxed (value);
gst_structure_get_uint (stream, "stream-type", &stream_type);
gst_structure_get_uint (stream, "pid", &stream_pid);
value = gst_structure_get_value (stream, "descriptors");
*body++ = stream_type;
GST_WRITE_UINT16_BE (body, stream_pid);
body += 2;
len = GPOINTER_TO_INT (lengths->data);
lengths = g_list_delete_link (lengths, lengths);
GST_WRITE_UINT16_BE (body, len);
body += 2;
if (len != 0) {
*body++ = cmd_id;
stream_descriptors = g_value_get_boxed (value);
body = write_ca_descriptors (body, stream_descriptors);
}
}
*size = body_size;
return buffer;
}
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