Skip to content

Commit

Permalink
Browse files Browse the repository at this point in the history
descrambler: split buffer to chunks with timestamps 
This allows to remove chunks with no longer valid keys in future.
  • Loading branch information
@perexg
perexg committed Oct 20, 2015
1 parent eec2096 commit f62114a
Show file tree
Hide file tree
Showing 2 changed files with 133 additions and 39 deletions.
4 changes: 3 additions & 1 deletion src/descrambler.h
View file
Expand Up @@ -29,6 +29,7 @@ struct elementary_stream;
struct tvhcsa;
struct mpegts_table;
struct mpegts_mux;
struct th_descrambler_data;

#define DESCRAMBLER_NONE 0
#define DESCRAMBLER_DES 1
Expand Down Expand Up @@ -73,7 +74,8 @@ typedef struct th_descrambler_runtime {
time_t dr_ecm_start[2];
time_t dr_ecm_last_key_time;
time_t dr_last_err;
sbuf_t dr_buf;
TAILQ_HEAD(, th_descrambler_data) dr_queue;
uint32_t dr_queue_total;
tvhlog_limit_t dr_loglimit_key;
uint8_t dr_key_even[16];
uint8_t dr_key_odd[16];
Expand Down
168 changes: 130 additions & 38 deletions src/descrambler/descrambler.c
View file
Expand Up @@ -32,8 +32,94 @@

#define MAX_QUICK_ECM_ENTRIES 100

typedef struct th_descrambler_data {
TAILQ_ENTRY(th_descrambler_data) dd_link;
time_t dd_timestamp;
sbuf_t dd_sbuf;
} th_descrambler_data_t;

TAILQ_HEAD(th_descrambler_queue, th_descrambler_data);

uint16_t *quick_ecm_table = NULL;

/*
*
*/
static void
descrambler_data_destroy(th_descrambler_runtime_t *dr, th_descrambler_data_t *dd)
{
if (dd) {
dr->dr_queue_total -= dd->dd_sbuf.sb_ptr;
TAILQ_REMOVE(&dr->dr_queue, dd, dd_link);
sbuf_free(&dd->dd_sbuf);
free(dd);
}
}

static void
descrambler_data_append(th_descrambler_runtime_t *dr, const uint8_t *tsb, int len)
{
th_descrambler_data_t *dd;

if (len == 0)
return;
dd = TAILQ_LAST(&dr->dr_queue, th_descrambler_queue);
if (dd && dd->dd_timestamp == dispatch_clock &&
(dd->dd_sbuf.sb_data[3] & 0x40) == (tsb[3] & 0x40)) { /* key match */
sbuf_append(&dd->dd_sbuf, tsb, len);
dr->dr_queue_total += len;
return;
}
dd = malloc(sizeof(*dd));
dd->dd_timestamp = dispatch_clock;
sbuf_init(&dd->dd_sbuf);
sbuf_append(&dd->dd_sbuf, tsb, len);
TAILQ_INSERT_TAIL(&dr->dr_queue, dd, dd_link);
dr->dr_queue_total += len;
}

static void
descrambler_data_cut(th_descrambler_runtime_t *dr, int len)
{
th_descrambler_data_t *dd;

while (len > 0 && (dd = TAILQ_FIRST(&dr->dr_queue)) != NULL) {
if (len < dd->dd_sbuf.sb_ptr) {
sbuf_cut(&dd->dd_sbuf, len);
dr->dr_queue_total -= len;
break;
}
len -= dd->dd_sbuf.sb_ptr;
descrambler_data_destroy(dr, dd);
}
}

static int
descrambler_data_key_check(th_descrambler_runtime_t *dr, uint8_t key, int len)
{
th_descrambler_data_t *dd = TAILQ_FIRST(&dr->dr_queue);
int off = 0;

if (dd == NULL)
return 0;
while (off < len) {
if (dd->dd_sbuf.sb_ptr <= off) {
dd = TAILQ_NEXT(dd, dd_link);
if (dd == NULL)
return 0;
len -= off;
off = 0;
}
if ((dd->dd_sbuf.sb_data[off + 3] & 0xc0) != key)
return 0;
off += 188;
}
return 1;
}

/*
*
*/
void
descrambler_init ( void )
{
Expand Down Expand Up @@ -130,7 +216,7 @@ descrambler_service_start ( service_t *t )
((mpegts_service_t *)t)->s_dvb_mux->mm_descrambler_flush = 0;
if (t->s_descramble == NULL) {
t->s_descramble = dr = calloc(1, sizeof(th_descrambler_runtime_t));
sbuf_init(&dr->dr_buf);
TAILQ_INIT(&dr->dr_queue);
dr->dr_key_index = 0xff;
tvhcsa_init(&dr->dr_csa);
}
Expand All @@ -146,6 +232,7 @@ descrambler_service_stop ( service_t *t )
{
th_descrambler_t *td;
th_descrambler_runtime_t *dr = t->s_descramble;
th_descrambler_data_t *dd;
void *p;

#if ENABLE_LINUXDVB_CA
Expand All @@ -161,7 +248,8 @@ descrambler_service_stop ( service_t *t )
free(p);
if (dr) {
tvhcsa_destroy(&dr->dr_csa);
sbuf_free(&dr->dr_buf);
while ((dd = TAILQ_FIRST(&dr->dr_queue)) != NULL)
descrambler_data_destroy(dr, dd);
free(dr);
}
}
Expand Down Expand Up @@ -456,10 +544,12 @@ descrambler_descramble ( service_t *t,
{
th_descrambler_t *td;
th_descrambler_runtime_t *dr = t->s_descramble;
int count, failed, resolved, off, len2, len3, flush_data = 0;
th_descrambler_data_t *dd, *dd_next;
int count, failed, resolved, len2, len3, flush_data = 0;
uint32_t dbuflen;
const uint8_t *tsb2;
uint8_t ki;
sbuf_t *sb;

lock_assert(&t->s_stream_mutex);

Expand All @@ -471,7 +561,7 @@ descrambler_descramble ( service_t *t,
return -1;
}

if (dr->dr_csa.csa_type == DESCRAMBLER_NONE && dr->dr_buf.sb_ptr == 0)
if (dr->dr_csa.csa_type == DESCRAMBLER_NONE && dr->dr_queue_total == 0)
if ((tsb[3] & 0x80) == 0) {
ts_recv_packet2((mpegts_service_t *)t, tsb, len);
return 1;
Expand Down Expand Up @@ -500,36 +590,41 @@ descrambler_descramble ( service_t *t,
}

/* process the queued TS packets */
if (dr->dr_buf.sb_ptr > 0) {
for (tsb2 = dr->dr_buf.sb_data, len2 = dr->dr_buf.sb_ptr;
len2 > 0; tsb2 += len3, len2 -= len3) {
ki = tsb2[3];
if ((ki & 0x80) != 0x00) {
if (key_valid(dr, ki) == 0) {
sbuf_cut(&dr->dr_buf, tsb2 - dr->dr_buf.sb_data);
goto next;
}
if (dr->dr_key_index != (ki & 0x40) &&
dr->dr_key_start + 2 < dispatch_clock) {
tvhtrace("descrambler", "stream key changed to %s for service \"%s\"",
(ki & 0x40) ? "odd" : "even",
((mpegts_service_t *)t)->s_dvb_svcname);
if (key_late(dr, ki)) {
if (ecm_reset(t, dr)) {
sbuf_cut(&dr->dr_buf, tsb2 - dr->dr_buf.sb_data);
flush_data = 1;
goto next;
if (dr->dr_queue_total > 0) {
for (dd = TAILQ_FIRST(&dr->dr_queue); dd; dd = dd_next) {
dd_next = TAILQ_NEXT(dd, dd_link);
sb = &dd->dd_sbuf;
tsb2 = sb->sb_data;
len2 = sb->sb_ptr;
for (; len2 > 0; tsb2 += len3, len2 -= len3) {
ki = tsb2[3];
if ((ki & 0x80) != 0x00) {
if (key_valid(dr, ki) == 0) {
sbuf_cut(sb, tsb2 - sb->sb_data);
goto next;
}
if (dr->dr_key_index != (ki & 0x40) &&
dr->dr_key_start + 2 < dispatch_clock) {
tvhtrace("descrambler", "stream key changed to %s for service \"%s\"",
(ki & 0x40) ? "odd" : "even",
((mpegts_service_t *)t)->s_dvb_svcname);
if (key_late(dr, ki)) {
if (ecm_reset(t, dr)) {
sbuf_cut(sb, tsb2 - sb->sb_data);
flush_data = 1;
goto next;
}
}
key_update(dr, ki);
}
key_update(dr, ki);
}
len3 = mpegts_word_count(tsb2, len2, 0xFF0000C0);
dr->dr_csa.csa_descramble(&dr->dr_csa, (mpegts_service_t *)t, tsb2, len3);
}
len3 = mpegts_word_count(tsb2, len2, 0xFF0000C0);
dr->dr_csa.csa_descramble(&dr->dr_csa, (mpegts_service_t *)t, tsb2, len3);
if (len2 == 0)
service_reset_streaming_status_flags(t, TSS_NO_ACCESS);
descrambler_data_destroy(dr, dd);
}
if (len2 == 0)
service_reset_streaming_status_flags(t, TSS_NO_ACCESS);
sbuf_free(&dr->dr_buf);
}

/* check for key change */
Expand Down Expand Up @@ -570,18 +665,15 @@ descrambler_descramble ( service_t *t,
if ((ki & 0x80) != 0x00) {
if (dr->dr_key_start == 0) {
/* do not use the first TS packet to decide - it may be wrong */
while (dr->dr_buf.sb_ptr > 20 * 188) {
for (off = 0; off < 20 * 188; off += 188)
if ((dr->dr_buf.sb_data[off + 3] & 0xc0) != (ki & 0xc0))
break;
if (off >= 20 * 188) {
while (dr->dr_queue_total > 20 * 188) {
if (descrambler_data_key_check(dr, ki & 0xc0, 20 * 188)) {
tvhtrace("descrambler", "initial stream key set to %s for service \"%s\"",
(ki & 0x40) ? "odd" : "even",
((mpegts_service_t *)t)->s_dvb_svcname);
key_update(dr, ki);
break;
} else {
sbuf_cut(&dr->dr_buf, 188);
descrambler_data_cut(dr, 188);
}
}
} else if (dr->dr_key_index != (ki & 0x40) &&
Expand All @@ -598,8 +690,8 @@ descrambler_descramble ( service_t *t,
* streaming faster.
*/
dbuflen = MAX(300, config.descrambler_buffer);
if (dr->dr_buf.sb_ptr >= dbuflen * 188) {
sbuf_cut(&dr->dr_buf, MAX((dbuflen / 10) * 188, len));
if (dr->dr_queue_total >= dbuflen * 188) {
descrambler_data_cut(dr, MAX((dbuflen / 10) * 188, len));
if (dr->dr_last_err + 10 < dispatch_clock) {
dr->dr_last_err = dispatch_clock;
tvherror("descrambler", "cannot decode packets for service \"%s\"",
Expand All @@ -609,7 +701,7 @@ descrambler_descramble ( service_t *t,
((mpegts_service_t *)t)->s_dvb_svcname);
}
}
sbuf_append(&dr->dr_buf, tsb, len);
descrambler_data_append(dr, tsb, len);
service_set_streaming_status_flags(t, TSS_NO_ACCESS);
}
} else {
Expand Down

0 comments on commit f62114a

Please sign in to comment.