dvb_demux.c

linux-2.6.15.6

/*
 * dvb_demux.c - DVB kernel demux API
 *
 * Copyright (C) 2000-2001 Ralph  Metzler <[e-mail]>
 *		       & Marcus Metzler <[e-mail]>
 *			 for convergence integrated media GmbH
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1
 * 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 Lesser General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 */

#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/module.h>
#include <linux/poll.h>
#include <linux/string.h>
#include <linux/crc32.h>
#include <asm/uaccess.h>

#include "dvb_demux.h"

#define NOBUFS
/*
** #define DVB_DEMUX_SECTION_LOSS_LOG to monitor payload loss in the syslog
*/
// #define DVB_DEMUX_SECTION_LOSS_LOG

/******************************************************************************
 * static inlined helper functions
 ******************************************************************************/

static inline u16 section_length(const u8 *buf)
{
	return 3 + ((buf[1] & 0x0f) << 8) + buf[2];
}

static inline u16 ts_pid(const u8 *buf)
{
	return ((buf[1] & 0x1f) << 8) + buf[2];
}

static inline u8 payload(const u8 *tsp)
{
	if (!(tsp[3] & 0x10))	// no payload?
		return 0;

	if (tsp[3] & 0x20) {	// adaptation field?
		if (tsp[4] > 183)	// corrupted data?
			return 0;
		else
			return 184 - 1 - tsp[4];
	}

	return 184;
}

static u32 dvb_dmx_crc32(struct dvb_demux_feed *f, const u8 *src, size_t len)
{
	return (f->feed.sec.crc_val = crc32_be(f->feed.sec.crc_val, src, len));
}

static void dvb_dmx_memcopy(struct dvb_demux_feed *f, u8 *d, const u8 *s,
			    size_t len)
{
	memcpy(d, s, len);
}

/******************************************************************************
 * Software filter functions
 ******************************************************************************/

static inline int dvb_dmx_swfilter_payload(struct dvb_demux_feed *feed,
					   const u8 *buf)
{
	int count = payload(buf);
	int p;
	//int ccok;
	//u8 cc;

	if (count == 0)
		return -1;

	p = 188 - count;

	/*
	cc = buf[3] & 0x0f;
	ccok = ((feed->cc + 1) & 0x0f) == cc;
	feed->cc = cc;
	if (!ccok)
		printk("missed packet!\n");
	*/

	if (buf[1] & 0x40)	// PUSI ?
		feed->peslen = 0xfffa;

	feed->peslen += count;

	return feed->cb.ts(&buf[p], count, NULL, 0, &feed->feed.ts, DMX_OK);
}

static int dvb_dmx_swfilter_sectionfilter(struct dvb_demux_feed *feed,
					  struct dvb_demux_filter *f)
{
	u8 neq = 0;
	int i;

	for (i = 0; i < DVB_DEMUX_MASK_MAX; i++) {
		u8 xor = f->filter.filter_value[i] ^ feed->feed.sec.secbuf[i];

		if (f->maskandmode[i] & xor)
			return 0;

		neq |= f->maskandnotmode[i] & xor;
	}

	if (f->doneq && !neq)
		return 0;

	return feed->cb.sec(feed->feed.sec.secbuf, feed->feed.sec.seclen,
			    NULL, 0, &f->filter, DMX_OK);
}

static inline int dvb_dmx_swfilter_section_feed(struct dvb_demux_feed *feed)
{
	struct dvb_demux *demux = feed->demux;
	struct dvb_demux_filter *f = feed->filter;
	struct dmx_section_feed *sec = &feed->feed.sec;
	int section_syntax_indicator;

	if (!sec->is_filtering)
		return 0;

	if (!f)
		return 0;

	if (sec->check_crc) {
		section_syntax_indicator = ((sec->secbuf[1] & 0x80) != 0);
		if (section_syntax_indicator &&
		    demux->check_crc32(feed, sec->secbuf, sec->seclen))
			return -1;
	}

	do {
		if (dvb_dmx_swfilter_sectionfilter(feed, f) < 0)
			return -1;
	} while ((f = f->next) && sec->is_filtering);

	sec->seclen = 0;

	return 0;
}

static void dvb_dmx_swfilter_section_new(struct dvb_demux_feed *feed)
{
	struct dmx_section_feed *sec = &feed->feed.sec;

#ifdef DVB_DEMUX_SECTION_LOSS_LOG
	if (sec->secbufp < sec->tsfeedp) {
		int i, n = sec->tsfeedp - sec->secbufp;

		/*
		 * Section padding is done with 0xff bytes entirely.
		 * Due to speed reasons, we won't check all of them
		 * but just first and last.
		 */
		if (sec->secbuf[0] != 0xff || sec->secbuf[n - 1] != 0xff) {
			printk("dvb_demux.c section ts padding loss: %d/%d\n",
			       n, sec->tsfeedp);
			printk("dvb_demux.c pad data:");
			for (i = 0; i < n; i++)
				printk(" %02x", sec->secbuf[i]);
			printk("\n");
		}
	}
#endif

	sec->tsfeedp = sec->secbufp = sec->seclen = 0;
	sec->secbuf = sec->secbuf_base;
}

/*
 * Losless Section Demux 1.4.1 by Emard
 * Valsecchi Patrick:
 *  - middle of section A  (no PUSI)
 *  - end of section A and start of section B
 *    (with PUSI pointing to the start of the second section)
 *
 *  In this case, without feed->pusi_seen you'll receive a garbage section
 *  consisting of the end of section A. Basically because tsfeedp
 *  is incemented and the use=0 condition is not raised
 *  when the second packet arrives.
 *
 * Fix:
 * when demux is started, let feed->pusi_seen = 0 to
 * prevent initial feeding of garbage from the end of
 * previous section. When you for the first time see PUSI=1
 * then set feed->pusi_seen = 1
 */
static int dvb_dmx_swfilter_section_copy_dump(struct dvb_demux_feed *feed,
					      const u8 *buf, u8 len)
{
	struct dvb_demux *demux = feed->demux;
	struct dmx_section_feed *sec = &feed->feed.sec;
	u16 limit, seclen, n;

	if (sec->tsfeedp >= DMX_MAX_SECFEED_SIZE)
		return 0;

	if (sec->tsfeedp + len > DMX_MAX_SECFEED_SIZE) {
#ifdef DVB_DEMUX_SECTION_LOSS_LOG
		printk("dvb_demux.c section buffer full loss: %d/%d\n",
		       sec->tsfeedp + len - DMX_MAX_SECFEED_SIZE,
		       DMX_MAX_SECFEED_SIZE);
#endif
		len = DMX_MAX_SECFEED_SIZE - sec->tsfeedp;
	}

	if (len <= 0)
		return 0;

	demux->memcopy(feed, sec->secbuf_base + sec->tsfeedp, buf, len);
	sec->tsfeedp += len;

	/*
	 * Dump all the sections we can find in the data (Emard)
	 */
	limit = sec->tsfeedp;
	if (limit > DMX_MAX_SECFEED_SIZE)
		return -1;	/* internal error should never happen */

	/* to be sure always set secbuf */
	sec->secbuf = sec->secbuf_base + sec->secbufp;

	for (n = 0; sec->secbufp + 2 < limit; n++) {
		seclen = section_length(sec->secbuf);
		if (seclen <= 0 || seclen > DMX_MAX_SECTION_SIZE
		    || seclen + sec->secbufp > limit)
			return 0;
		sec->seclen = seclen;
		sec->crc_val = ~0;
		/* dump [secbuf .. secbuf+seclen) */
		if (feed->pusi_seen)
			dvb_dmx_swfilter_section_feed(feed);
#ifdef DVB_DEMUX_SECTION_LOSS_LOG
		else
			printk("dvb_demux.c pusi not seen, discarding section data\n");
#endif
		sec->secbufp += seclen;	/* secbufp and secbuf moving together is */
		sec->secbuf += seclen;	/* redundant but saves pointer arithmetic */
	}

	return 0;
}

static int dvb_dmx_swfilter_section_packet(struct dvb_demux_feed *feed,
					   const u8 *buf)
{
	u8 p, count;
	int ccok, dc_i = 0;
	u8 cc;

	count = payload(buf);

	if (count == 0)		/* count == 0 if no payload or out of range */
		return -1;

	p = 188 - count;	/* payload start */

	cc = buf[3] & 0x0f;
	ccok = ((feed->cc + 1) & 0x0f) == cc;
	feed->cc = cc;

	if (buf[3] & 0x20) {
		/* adaption field present, check for discontinuity_indicator */
		if ((buf[4] > 0) && (buf[5] & 0x80))
			dc_i = 1;
	}

	if (!ccok || dc_i) {
#ifdef DVB_DEMUX_SECTION_LOSS_LOG
		printk("dvb_demux.c discontinuity detected %d bytes lost\n",
		       count);
		/*
		 * those bytes under sume circumstances will again be reported
		 * in the following dvb_dmx_swfilter_section_new
		 */
#endif
		/*
		 * Discontinuity detected. Reset pusi_seen = 0 to
		 * stop feeding of suspicious data until next PUSI=1 arrives
		 */
		feed->pusi_seen = 0;
		dvb_dmx_swfilter_section_new(feed);
	}

	if (buf[1] & 0x40) {
		/* PUSI=1 (is set), section boundary is here */
		if (count > 1 && buf[p] < count) {
			const u8 *before = &buf[p + 1];
			u8 before_len = buf[p];
			const u8 *after = &before[before_len];
			u8 after_len = count - 1 - before_len;

			dvb_dmx_swfilter_section_copy_dump(feed, before,
							   before_len);
			/* before start of new section, set pusi_seen = 1 */
			feed->pusi_seen = 1;
			dvb_dmx_swfilter_section_new(feed);
			dvb_dmx_swfilter_section_copy_dump(feed, after,
							   after_len);
		}
#ifdef DVB_DEMUX_SECTION_LOSS_LOG
		else if (count > 0)
			printk("dvb_demux.c PUSI=1 but %d bytes lost\n", count);
#endif
	} else {
		/* PUSI=0 (is not set), no section boundary */
		dvb_dmx_swfilter_section_copy_dump(feed, &buf[p], count);
	}

	return 0;
}

static inline void dvb_dmx_swfilter_packet_type(struct dvb_demux_feed *feed,
						const u8 *buf)
{
	switch (feed->type) {
	case DMX_TYPE_TS:
		if (!feed->feed.ts.is_filtering)
			break;
		if (feed->ts_type & TS_PACKET) {
			if (feed->ts_type & TS_PAYLOAD_ONLY)
				dvb_dmx_swfilter_payload(feed, buf);
			else
				feed->cb.ts(buf, 188, NULL, 0, &feed->feed.ts,
					    DMX_OK);
		}
		if (feed->ts_type & TS_DECODER)
			if (feed->demux->write_to_decoder)
				feed->demux->write_to_decoder(feed, buf, 188);
		break;

	case DMX_TYPE_SEC:
		if (!feed->feed.sec.is_filtering)
			break;
		if (dvb_dmx_swfilter_section_packet(feed, buf) < 0)
			feed->feed.sec.seclen = feed->feed.sec.secbufp = 0;
		break;

	default:
		break;
	}
}

#define DVR_FEED(f)							\
	(((f)->type == DMX_TYPE_TS) &&					\
	((f)->feed.ts.is_filtering) &&					\
	(((f)->ts_type & (TS_PACKET|TS_PAYLOAD_ONLY)) == TS_PACKET))

static void dvb_dmx_swfilter_packet(struct dvb_demux *demux, const u8 *buf)
{
	struct dvb_demux_feed *feed;
	struct list_head *pos, *head = &demux->feed_list;
	u16 pid = ts_pid(buf);
	int dvr_done = 0;

	list_for_each(pos, head) {
		feed = list_entry(pos, struct dvb_demux_feed, list_head);

		if ((feed->pid != pid) && (feed->pid != 0x2000))
			continue;

		/* copy each packet only once to the dvr device, even
		 * if a PID is in multiple filters (e.g. video + PCR) */
		if ((DVR_FEED(feed)) && (dvr_done++))
			continue;

		if (feed->pid == pid) {
			dvb_dmx_swfilter_packet_type(feed, buf);
			if (DVR_FEED(feed))
				continue;
		}

		if (feed->pid == 0x2000)
			feed->cb.ts(buf, 188, NULL, 0, &feed->feed.ts, DMX_OK);
	}
}

void dvb_dmx_swfilter_packets(struct dvb_demux *demux, const u8 *buf,
			      size_t count)
{
	spin_lock(&demux->lock);

	while (count--) {
		if (buf[0] == 0x47)
			dvb_dmx_swfilter_packet(demux, buf);
		buf += 188;
	}

	spin_unlock(&demux->lock);
}

EXPORT_SYMBOL(dvb_dmx_swfilter_packets);

void dvb_dmx_swfilter(struct dvb_demux *demux, const u8 *buf, size_t count)
{
	int p = 0, i, j;

	spin_lock(&demux->lock);

	if (demux->tsbufp) {
		i = demux->tsbufp;
		j = 188 - i;
		if (count < j) {
			memcpy(&demux->tsbuf[i], buf, count);
			demux->tsbufp += count;
			goto bailout;
		}
		memcpy(&demux->tsbuf[i], buf, j);
		if (demux->tsbuf[0] == 0x47)
			dvb_dmx_swfilter_packet(demux, demux->tsbuf);
		demux->tsbufp = 0;
		p += j;
	}

	while (p < count) {
		if (buf[p] == 0x47) {
			if (count - p >= 188) {
				dvb_dmx_swfilter_packet(demux, &buf[p]);
				p += 188;
			} else {
				i = count - p;
				memcpy(demux->tsbuf, &buf[p], i);
				demux->tsbufp = i;
				goto bailout;
			}
		} else
			p++;
	}

bailout:
	spin_unlock(&demux->lock);
}

EXPORT_SYMBOL(dvb_dmx_swfilter);

void dvb_dmx_swfilter_204(struct dvb_demux *demux, const u8 *buf, size_t count)
{
	int p = 0, i, j;
	u8 tmppack[188];

	spin_lock(&demux->lock);

	if (demux->tsbufp) {
		i = demux->tsbufp;
		j = 204 - i;
		if (count < j) {
			memcpy(&demux->tsbuf[i], buf, count);
			demux->tsbufp += count;
			goto bailout;
		}
		memcpy(&demux->tsbuf[i], buf, j);
		if ((demux->tsbuf[0] == 0x47) | (demux->tsbuf[0] == 0xB8)) {
			memcpy(tmppack, demux->tsbuf, 188);
			if (tmppack[0] == 0xB8)
				tmppack[0] = 0x47;
			dvb_dmx_swfilter_packet(demux, tmppack);
		}
		demux->tsbufp = 0;
		p += j;
	}

	while (p < count) {
		if ((buf[p] == 0x47) | (buf[p] == 0xB8)) {
			if (count - p >= 204) {
				memcpy(tmppack, &buf[p], 188);
				if (tmppack[0] == 0xB8)
					tmppack[0] = 0x47;
				dvb_dmx_swfilter_packet(demux, tmppack);
				p += 204;
			} else {
				i = count - p;
				memcpy(demux->tsbuf, &buf[p], i);
				demux->tsbufp = i;
				goto bailout;
			}
		} else {
			p++;
		}
	}

bailout:
	spin_unlock(&demux->lock);
}

EXPORT_SYMBOL(dvb_dmx_swfilter_204);

static struct dvb_demux_filter *dvb_dmx_filter_alloc(struct dvb_demux *demux)
{
	int i;

	for (i = 0; i < demux->filternum; i++)
		if (demux->filter[i].state == DMX_STATE_FREE)
			break;

	if (i == demux->filternum)
		return NULL;

	demux->filter[i].state = DMX_STATE_ALLOCATED;

	return &demux->filter[i];
}

static struct dvb_demux_feed *dvb_dmx_feed_alloc(struct dvb_demux *demux)
{
	int i;

	for (i = 0; i < demux->feednum; i++)
		if (demux->feed[i].state == DMX_STATE_FREE)
			break;

	if (i == demux->feednum)
		return NULL;

	demux->feed[i].state = DMX_STATE_ALLOCATED;

	return &demux->feed[i];
}

static int dvb_demux_feed_find(struct dvb_demux_feed *feed)
{
	struct dvb_demux_feed *entry;

	list_for_each_entry(entry, &feed->demux->feed_list, list_head)
		if (entry == feed)
			return 1;

	return 0;
}

static void dvb_demux_feed_add(struct dvb_demux_feed *feed)
{
	spin_lock_irq(&feed->demux->lock);
	if (dvb_demux_feed_find(feed)) {
		printk(KERN_ERR "%s: feed already in list (type=%x state=%x pid=%x)\n",
		       __FUNCTION__, feed->type, feed->state, feed->pid);
		goto out;
	}

	list_add(&feed->list_head, &feed->demux->feed_list);
out:
	spin_unlock_irq(&feed->demux->lock);
}

static void dvb_demux_feed_del(struct dvb_demux_feed *feed)
{
	spin_lock_irq(&feed->demux->lock);
	if (!(dvb_demux_feed_find(feed))) {
		printk(KERN_ERR "%s: feed not in list (type=%x state=%x pid=%x)\n",
		       __FUNCTION__, feed->type, feed->state, feed->pid);
		goto out;
	}

	list_del(&feed->list_head);
out:
	spin_unlock_irq(&feed->demux->lock);
}

static int dmx_ts_feed_set(struct dmx_ts_feed *ts_feed, u16 pid, int ts_type,
			   enum dmx_ts_pes pes_type,
			   size_t circular_buffer_size, struct timespec timeout)
{
	struct dvb_demux_feed *feed = (struct dvb_demux_feed *)ts_feed;
	struct dvb_demux *demux = feed->demux;

	if (pid > DMX_MAX_PID)
		return -EINVAL;

	if (down_interruptible(&demux->mutex))
		return -ERESTARTSYS;

	if (ts_type & TS_DECODER) {
		if (pes_type >= DMX_TS_PES_OTHER) {
			up(&demux->mutex);
			return -EINVAL;
		}

		if (demux->pesfilter[pes_type] &&
		    demux->pesfilter[pes_type] != feed) {
			up(&demux->mutex);
			return -EINVAL;
		}

		demux->pesfilter[pes_type] = feed;
		demux->pids[pes_type] = pid;
	}

	dvb_demux_feed_add(feed);

	feed->pid = pid;
	feed->buffer_size = circular_buffer_size;
	feed->timeout = timeout;
	feed->ts_type = ts_type;
	feed->pes_type = pes_type;