usb_hid.c revision 195967 
1/*	$NetBSD: hid.c,v 1.17 2001/11/13 06:24:53 lukem Exp $	*/
2
3
4#include <sys/cdefs.h>
5__FBSDID("$FreeBSD: head/sys/dev/usb/usb_hid.c 195967 2009-07-30 00:17:08Z alfred $");
6/*-
7 * Copyright (c) 1998 The NetBSD Foundation, Inc.
8 * All rights reserved.
9 *
10 * This code is derived from software contributed to The NetBSD Foundation
11 * by Lennart Augustsson (lennart@augustsson.net) at
12 * Carlstedt Research & Technology.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
16 * are met:
17 * 1. Redistributions of source code must retain the above copyright
18 *    notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 *    notice, this list of conditions and the following disclaimer in the
21 *    documentation and/or other materials provided with the distribution.
22 * 3. All advertising materials mentioning features or use of this software
23 *    must display the following acknowledgement:
24 *        This product includes software developed by the NetBSD
25 *        Foundation, Inc. and its contributors.
26 * 4. Neither the name of The NetBSD Foundation nor the names of its
27 *    contributors may be used to endorse or promote products derived
28 *    from this software without specific prior written permission.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
31 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
32 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
33 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
34 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
35 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
36 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
37 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
38 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
39 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
40 * POSSIBILITY OF SUCH DAMAGE.
41 */
42
43#include <sys/stdint.h>
44#include <sys/stddef.h>
45#include <sys/param.h>
46#include <sys/queue.h>
47#include <sys/types.h>
48#include <sys/systm.h>
49#include <sys/kernel.h>
50#include <sys/bus.h>
51#include <sys/linker_set.h>
52#include <sys/module.h>
53#include <sys/lock.h>
54#include <sys/mutex.h>
55#include <sys/condvar.h>
56#include <sys/sysctl.h>
57#include <sys/sx.h>
58#include <sys/unistd.h>
59#include <sys/callout.h>
60#include <sys/malloc.h>
61#include <sys/priv.h>
62
63#include <dev/usb/usb.h>
64#include <dev/usb/usbdi.h>
65#include <dev/usb/usbdi_util.h>
66#include <dev/usb/usbhid.h>
67
68#define	USB_DEBUG_VAR usb_debug
69
70#include <dev/usb/usb_core.h>
71#include <dev/usb/usb_debug.h>
72#include <dev/usb/usb_process.h>
73#include <dev/usb/usb_device.h>
74#include <dev/usb/usb_request.h>
75
76static void hid_clear_local(struct hid_item *);
77static uint8_t hid_get_byte(struct hid_data *s, const uint16_t wSize);
78
79#define	MAXUSAGE 64
80#define	MAXPUSH 4
81#define	MAXID 16
82
83struct hid_pos_data {
84	int32_t rid;
85	uint32_t pos;
86};
87
88struct hid_data {
89	const uint8_t *start;
90	const uint8_t *end;
91	const uint8_t *p;
92	struct hid_item cur[MAXPUSH];
93	struct hid_pos_data last_pos[MAXID];
94	int32_t	usages_min[MAXUSAGE];
95	int32_t	usages_max[MAXUSAGE];
96	int32_t usage_last;	/* last seen usage */
97	uint32_t loc_size;	/* last seen size */
98	uint32_t loc_count;	/* last seen count */
99	uint8_t	kindset;	/* we have 5 kinds so 8 bits are enough */
100	uint8_t	pushlevel;	/* current pushlevel */
101	uint8_t	ncount;		/* end usage item count */
102	uint8_t icount;		/* current usage item count */
103	uint8_t	nusage;		/* end "usages_min/max" index */
104	uint8_t	iusage;		/* current "usages_min/max" index */
105	uint8_t ousage;		/* current "usages_min/max" offset */
106	uint8_t	susage;		/* usage set flags */
107};
108
109/*------------------------------------------------------------------------*
110 *	hid_clear_local
111 *------------------------------------------------------------------------*/
112static void
113hid_clear_local(struct hid_item *c)
114{
115
116	c->loc.count = 0;
117	c->loc.size = 0;
118	c->usage = 0;
119	c->usage_minimum = 0;
120	c->usage_maximum = 0;
121	c->designator_index = 0;
122	c->designator_minimum = 0;
123	c->designator_maximum = 0;
124	c->string_index = 0;
125	c->string_minimum = 0;
126	c->string_maximum = 0;
127	c->set_delimiter = 0;
128}
129
130static void
131hid_switch_rid(struct hid_data *s, struct hid_item *c, int32_t next_rID)
132{
133	uint8_t i;
134
135	/* check for same report ID - optimise */
136
137	if (c->report_ID == next_rID)
138		return;
139
140	/* save current position for current rID */
141
142	if (c->report_ID == 0) {
143		i = 0;
144	} else {
145		for (i = 1; i != MAXID; i++) {
146			if (s->last_pos[i].rid == c->report_ID)
147				break;
148			if (s->last_pos[i].rid == 0)
149				break;
150		}
151	}
152	if (i != MAXID) {
153		s->last_pos[i].rid = c->report_ID;
154		s->last_pos[i].pos = c->loc.pos;
155	}
156
157	/* store next report ID */
158
159	c->report_ID = next_rID;
160
161	/* lookup last position for next rID */
162
163	if (next_rID == 0) {
164		i = 0;
165	} else {
166		for (i = 1; i != MAXID; i++) {
167			if (s->last_pos[i].rid == next_rID)
168				break;
169			if (s->last_pos[i].rid == 0)
170				break;
171		}
172	}
173	if (i != MAXID) {
174		s->last_pos[i].rid = next_rID;
175		c->loc.pos = s->last_pos[i].pos;
176	} else {
177		DPRINTF("Out of RID entries, position is set to zero!\n");
178		c->loc.pos = 0;
179	}
180}
181
182/*------------------------------------------------------------------------*
183 *	hid_start_parse
184 *------------------------------------------------------------------------*/
185struct hid_data *
186hid_start_parse(const void *d, usb_size_t len, int kindset)
187{
188	struct hid_data *s;
189
190	if ((kindset-1) & kindset) {
191		DPRINTFN(0, "Only one bit can be "
192		    "set in the kindset\n");
193		return (NULL);
194	}
195
196	s = malloc(sizeof *s, M_TEMP, M_WAITOK | M_ZERO);
197	s->start = s->p = d;
198	s->end = ((const uint8_t *)d) + len;
199	s->kindset = kindset;
200	return (s);
201}
202
203/*------------------------------------------------------------------------*
204 *	hid_end_parse
205 *------------------------------------------------------------------------*/
206void
207hid_end_parse(struct hid_data *s)
208{
209	if (s == NULL)
210		return;
211
212	free(s, M_TEMP);
213}
214
215/*------------------------------------------------------------------------*
216 *	get byte from HID descriptor
217 *------------------------------------------------------------------------*/
218static uint8_t
219hid_get_byte(struct hid_data *s, const uint16_t wSize)
220{
221	const uint8_t *ptr;
222	uint8_t retval;
223
224	ptr = s->p;
225
226	/* check if end is reached */
227	if (ptr == s->end)
228		return (0);
229
230	/* read out a byte */
231	retval = *ptr;
232
233	/* check if data pointer can be advanced by "wSize" bytes */
234	if ((s->end - ptr) < wSize)
235		ptr = s->end;
236	else
237		ptr += wSize;
238
239	/* update pointer */
240	s->p = ptr;
241
242	return (retval);
243}
244
245/*------------------------------------------------------------------------*
246 *	hid_get_item
247 *------------------------------------------------------------------------*/
248int
249hid_get_item(struct hid_data *s, struct hid_item *h)
250{
251	struct hid_item *c;
252	unsigned int bTag, bType, bSize;
253	uint32_t oldpos;
254	int32_t mask;
255	int32_t dval;
256
257	if (s == NULL)
258		return (0);
259
260	c = &s->cur[s->pushlevel];
261
262 top:
263	/* check if there is an array of items */
264	if (s->icount < s->ncount) {
265		/* get current usage */
266		if (s->iusage < s->nusage) {
267			dval = s->usages_min[s->iusage] + s->ousage;
268			c->usage = dval;
269			s->usage_last = dval;
270			if (dval == s->usages_max[s->iusage]) {
271				s->iusage ++;
272				s->ousage = 0;
273			} else {
274				s->ousage ++;
275			}
276		} else {
277			DPRINTFN(1, "Using last usage\n");
278			dval = s->usage_last;
279		}
280		s->icount ++;
281		/*
282		 * Only copy HID item, increment position and return
283		 * if correct kindset!
284		 */
285		if (s->kindset & (1 << c->kind)) {
286			*h = *c;
287			DPRINTFN(1, "%u,%u,%u\n", h->loc.pos,
288			    h->loc.size, h->loc.count);
289			c->loc.pos += c->loc.size * c->loc.count;
290			return (1);
291		}
292	}
293
294	/* reset state variables */
295	s->icount = 0;
296	s->ncount = 0;
297	s->iusage = 0;
298	s->nusage = 0;
299	s->susage = 0;
300	s->ousage = 0;
301	hid_clear_local(c);
302
303	/* get next item */
304	while (s->p != s->end) {
305
306		bSize = hid_get_byte(s, 1);
307		if (bSize == 0xfe) {
308			/* long item */
309			bSize = hid_get_byte(s, 1);
310			bSize |= hid_get_byte(s, 1) << 8;
311			bTag = hid_get_byte(s, 1);
312			bType = 0xff;	/* XXX what should it be */
313		} else {
314			/* short item */
315			bTag = bSize >> 4;
316			bType = (bSize >> 2) & 3;
317			bSize &= 3;
318			if (bSize == 3)
319				bSize = 4;
320		}
321		switch (bSize) {
322		case 0:
323			dval = 0;
324			mask = 0;
325			break;
326		case 1:
327			dval = (int8_t)hid_get_byte(s, 1);
328			mask = 0xFF;
329			break;
330		case 2:
331			dval = hid_get_byte(s, 1);
332			dval |= hid_get_byte(s, 1) << 8;
333			dval = (int16_t)dval;
334			mask = 0xFFFF;
335			break;
336		case 4:
337			dval = hid_get_byte(s, 1);
338			dval |= hid_get_byte(s, 1) << 8;
339			dval |= hid_get_byte(s, 1) << 16;
340			dval |= hid_get_byte(s, 1) << 24;
341			mask = 0xFFFFFFFF;
342			break;
343		default:
344			dval = hid_get_byte(s, bSize);
345			DPRINTFN(0, "bad length %u (data=0x%02x)\n",
346			    bSize, dval);
347			continue;
348		}
349
350		switch (bType) {
351		case 0:		/* Main */
352			switch (bTag) {
353			case 8:	/* Input */
354				c->kind = hid_input;
355				c->flags = dval;
356		ret:
357				c->loc.count = s->loc_count;
358				c->loc.size = s->loc_size;
359
360				if (c->flags & HIO_VARIABLE) {
361					/* range check usage count */
362					if (c->loc.count > 255) {
363						DPRINTFN(0, "Number of "
364						    "items truncated to 255\n");
365						s->ncount = 255;
366					} else
367						s->ncount = c->loc.count;
368
369					/*
370					 * The "top" loop will return
371					 * one and one item:
372					 */
373					c->loc.count = 1;
374				} else {
375					s->ncount = 1;
376				}
377				goto top;
378
379			case 9:	/* Output */
380				c->kind = hid_output;
381				c->flags = dval;
382				goto ret;
383			case 10:	/* Collection */
384				c->kind = hid_collection;
385				c->collection = dval;
386				c->collevel++;
387				c->usage = s->usage_last;
388				*h = *c;
389				return (1);
390			case 11:	/* Feature */
391				c->kind = hid_feature;
392				c->flags = dval;
393				goto ret;
394			case 12:	/* End collection */
395				c->kind = hid_endcollection;
396				if (c->collevel == 0) {
397					DPRINTFN(0, "invalid end collection\n");
398					return (0);
399				}
400				c->collevel--;
401				*h = *c;
402				return (1);
403			default:
404				DPRINTFN(0, "Main bTag=%d\n", bTag);
405				break;
406			}
407			break;
408		case 1:		/* Global */
409			switch (bTag) {
410			case 0:
411				c->_usage_page = dval << 16;
412				break;
413			case 1:
414				c->logical_minimum = dval;
415				break;
416			case 2:
417				c->logical_maximum = dval;
418				break;
419			case 3:
420				c->physical_minimum = dval;
421				break;
422			case 4:
423				c->physical_maximum = dval;
424				break;
425			case 5:
426				c->unit_exponent = dval;
427				break;
428			case 6:
429				c->unit = dval;
430				break;
431			case 7:
432				/* mask because value is unsigned */
433				s->loc_size = dval & mask;
434				break;
435			case 8:
436				hid_switch_rid(s, c, dval);
437				break;
438			case 9:
439				/* mask because value is unsigned */
440				s->loc_count = dval & mask;
441				break;
442			case 10:	/* Push */
443				s->pushlevel ++;
444				if (s->pushlevel < MAXPUSH) {
445					s->cur[s->pushlevel] = *c;
446					/* store size and count */
447					c->loc.size = s->loc_size;
448					c->loc.count = s->loc_count;
449					/* update current item pointer */
450					c = &s->cur[s->pushlevel];
451				} else {
452					DPRINTFN(0, "Cannot push "
453					    "item @ %d!\n", s->pushlevel);
454				}
455				break;
456			case 11:	/* Pop */
457				s->pushlevel --;
458				if (s->pushlevel < MAXPUSH) {
459					/* preserve position */
460					oldpos = c->loc.pos;
461					c = &s->cur[s->pushlevel];
462					/* restore size and count */
463					s->loc_size = c->loc.size;
464					s->loc_count = c->loc.count;
465					/* set default item location */
466					c->loc.pos = oldpos;
467					c->loc.size = 0;
468					c->loc.count = 0;
469				} else {
470					DPRINTFN(0, "Cannot pop "
471					    "item @ %d!\n", s->pushlevel);
472				}
473				break;
474			default:
475				DPRINTFN(0, "Global bTag=%d\n", bTag);
476				break;
477			}
478			break;
479		case 2:		/* Local */
480			switch (bTag) {
481			case 0:
482				if (bSize != 4)
483					dval = (dval & mask) | c->_usage_page;
484
485				/* set last usage, in case of a collection */
486				s->usage_last = dval;
487
488				if (s->nusage < MAXUSAGE) {
489					s->usages_min[s->nusage] = dval;
490					s->usages_max[s->nusage] = dval;
491					s->nusage ++;
492				} else {
493					DPRINTFN(0, "max usage reached!\n");
494				}
495
496				/* clear any pending usage sets */
497				s->susage = 0;
498				break;
499			case 1:
500				s->susage |= 1;
501
502				if (bSize != 4)
503					dval = (dval & mask) | c->_usage_page;
504				c->usage_minimum = dval;
505
506				goto check_set;
507			case 2:
508				s->susage |= 2;
509
510				if (bSize != 4)
511					dval = (dval & mask) | c->_usage_page;
512				c->usage_maximum = dval;
513
514			check_set:
515				if (s->susage != 3)
516					break;
517
518				/* sanity check */
519				if ((s->nusage < MAXUSAGE) &&
520				    (c->usage_minimum <= c->usage_maximum)) {
521					/* add usage range */
522					s->usages_min[s->nusage] =
523					    c->usage_minimum;
524					s->usages_max[s->nusage] =
525					    c->usage_maximum;
526					s->nusage ++;
527				} else {
528					DPRINTFN(0, "Usage set dropped!\n");
529				}
530				s->susage = 0;
531				break;
532			case 3:
533				c->designator_index = dval;
534				break;
535			case 4:
536				c->designator_minimum = dval;
537				break;
538			case 5:
539				c->designator_maximum = dval;
540				break;
541			case 7:
542				c->string_index = dval;
543				break;
544			case 8:
545				c->string_minimum = dval;
546				break;
547			case 9:
548				c->string_maximum = dval;
549				break;
550			case 10:
551				c->set_delimiter = dval;
552				break;
553			default:
554				DPRINTFN(0, "Local bTag=%d\n", bTag);
555				break;
556			}
557			break;
558		default:
559			DPRINTFN(0, "default bType=%d\n", bType);
560			break;
561		}
562	}
563	return (0);
564}
565
566/*------------------------------------------------------------------------*
567 *	hid_report_size
568 *------------------------------------------------------------------------*/
569int
570hid_report_size(const void *buf, usb_size_t len, enum hid_kind k, uint8_t *id)
571{
572	struct hid_data *d;
573	struct hid_item h;
574	uint32_t temp;
575	uint32_t hpos;
576	uint32_t lpos;
577	uint8_t any_id;
578
579	any_id = 0;
580	hpos = 0;
581	lpos = 0xFFFFFFFF;
582
583	for (d = hid_start_parse(buf, len, 1 << k); hid_get_item(d, &h);) {
584		if (h.kind == k) {
585			/* check for ID-byte presense */
586			if ((h.report_ID != 0) && !any_id) {
587				if (id != NULL)
588					*id = h.report_ID;
589				any_id = 1;
590			}
591			/* compute minimum */
592			if (lpos > h.loc.pos)
593				lpos = h.loc.pos;
594			/* compute end position */
595			temp = h.loc.pos + (h.loc.size * h.loc.count);
596			/* compute maximum */
597			if (hpos < temp)
598				hpos = temp;
599		}
600	}
601	hid_end_parse(d);
602
603	/* safety check - can happen in case of currupt descriptors */
604	if (lpos > hpos)
605		temp = 0;
606	else
607		temp = hpos - lpos;
608
609	/* check for ID byte */
610	if (any_id)
611		temp += 8;
612	else if (id != NULL)
613		*id = 0;
614
615	/* return length in bytes rounded up */
616	return ((temp + 7) / 8);
617}
618
619/*------------------------------------------------------------------------*
620 *	hid_locate
621 *------------------------------------------------------------------------*/
622int
623hid_locate(const void *desc, usb_size_t size, uint32_t u, enum hid_kind k,
624    uint8_t index, struct hid_location *loc, uint32_t *flags, uint8_t *id)
625{
626	struct hid_data *d;
627	struct hid_item h;
628
629	for (d = hid_start_parse(desc, size, 1 << k); hid_get_item(d, &h);) {
630		if (h.kind == k && !(h.flags & HIO_CONST) && h.usage == u) {
631			if (index--)
632				continue;
633			if (loc != NULL)
634				*loc = h.loc;
635			if (flags != NULL)
636				*flags = h.flags;
637			if (id != NULL)
638				*id = h.report_ID;
639			hid_end_parse(d);
640			return (1);
641		}
642	}
643	if (loc != NULL)
644		loc->size = 0;
645	if (flags != NULL)
646		*flags = 0;
647	if (id != NULL)
648		*id = 0;
649	hid_end_parse(d);
650	return (0);
651}
652
653/*------------------------------------------------------------------------*
654 *	hid_get_data
655 *------------------------------------------------------------------------*/
656uint32_t
657hid_get_data(const uint8_t *buf, usb_size_t len, struct hid_location *loc)
658{
659	uint32_t hpos = loc->pos;
660	uint32_t hsize = loc->size;
661	uint32_t data;
662	uint32_t rpos;
663	uint8_t n;
664
665	DPRINTFN(11, "hid_get_data: loc %d/%d\n", hpos, hsize);
666
667	/* Range check and limit */
668	if (hsize == 0)
669		return (0);
670	if (hsize > 32)
671		hsize = 32;
672
673	/* Get data in a safe way */
674	data = 0;
675	rpos = (hpos / 8);
676	n = (hsize + 7) / 8;
677	rpos += n;
678	while (n--) {
679		rpos--;
680		if (rpos < len)
681			data |= buf[rpos] << (8 * n);
682	}
683
684	/* Correctly shift down data */
685	data = (data >> (hpos % 8));
686
687	/* Mask and sign extend in one */
688	n = 32 - hsize;
689	data = ((int32_t)data << n) >> n;
690
691	DPRINTFN(11, "hid_get_data: loc %d/%d = %lu\n",
692	    loc->pos, loc->size, (long)data);
693	return (data);
694}
695
696/*------------------------------------------------------------------------*
697 *	hid_is_collection
698 *------------------------------------------------------------------------*/
699int
700hid_is_collection(const void *desc, usb_size_t size, uint32_t usage)
701{
702	struct hid_data *hd;
703	struct hid_item hi;
704	int err;
705
706	hd = hid_start_parse(desc, size, hid_input);
707	if (hd == NULL)
708		return (0);
709
710	while ((err = hid_get_item(hd, &hi))) {
711		 if (hi.kind == hid_collection &&
712		     hi.usage == usage)
713			break;
714	}
715	hid_end_parse(hd);
716	return (err);
717}
718
719/*------------------------------------------------------------------------*
720 *	hid_get_descriptor_from_usb
721 *
722 * This function will search for a HID descriptor between two USB
723 * interface descriptors.
724 *
725 * Return values:
726 * NULL: No more HID descriptors.
727 * Else: Pointer to HID descriptor.
728 *------------------------------------------------------------------------*/
729struct usb_hid_descriptor *
730hid_get_descriptor_from_usb(struct usb_config_descriptor *cd,
731    struct usb_interface_descriptor *id)
732{
733	struct usb_descriptor *desc = (void *)id;
734
735	if (desc == NULL) {
736		return (NULL);
737	}
738	while ((desc = usb_desc_foreach(cd, desc))) {
739		if ((desc->bDescriptorType == UDESC_HID) &&
740		    (desc->bLength >= USB_HID_DESCRIPTOR_SIZE(0))) {
741			return (void *)desc;
742		}
743		if (desc->bDescriptorType == UDESC_INTERFACE) {
744			break;
745		}
746	}
747	return (NULL);
748}
749
750/*------------------------------------------------------------------------*
751 *	usbd_req_get_hid_desc
752 *
753 * This function will read out an USB report descriptor from the USB
754 * device.
755 *
756 * Return values:
757 * NULL: Failure.
758 * Else: Success. The pointer should eventually be passed to free().
759 *------------------------------------------------------------------------*/
760usb_error_t
761usbd_req_get_hid_desc(struct usb_device *udev, struct mtx *mtx,
762    void **descp, uint16_t *sizep,
763    struct malloc_type *mem, uint8_t iface_index)
764{
765	struct usb_interface *iface = usbd_get_iface(udev, iface_index);
766	struct usb_hid_descriptor *hid;
767	usb_error_t err;
768
769	if ((iface == NULL) || (iface->idesc == NULL)) {
770		return (USB_ERR_INVAL);
771	}
772	hid = hid_get_descriptor_from_usb
773	    (usbd_get_config_descriptor(udev), iface->idesc);
774
775	if (hid == NULL) {
776		return (USB_ERR_IOERROR);
777	}
778	*sizep = UGETW(hid->descrs[0].wDescriptorLength);
779	if (*sizep == 0) {
780		return (USB_ERR_IOERROR);
781	}
782	if (mtx)
783		mtx_unlock(mtx);
784
785	*descp = malloc(*sizep, mem, M_ZERO | M_WAITOK);
786
787	if (mtx)
788		mtx_lock(mtx);
789
790	if (*descp == NULL) {
791		return (USB_ERR_NOMEM);
792	}
793	err = usbd_req_get_report_descriptor
794	    (udev, mtx, *descp, *sizep, iface_index);
795
796	if (err) {
797		free(*descp, mem);
798		*descp = NULL;
799		return (err);
800	}
801	return (USB_ERR_NORMAL_COMPLETION);
802}
803