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net: Allow binding of unspecified address without address existance
[dragonfly.git] / lib / libusb / libusb20_desc.c
bloba25b9e34df3c1f6509b6da26cb745091513f127e
1 /* $FreeBSD: head/lib/libusb/libusb20_desc.c 248236 2013-03-13 12:23:14Z hselasky $ */
2 /*-
3 * Copyright (c) 2008 Hans Petter Selasky. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #ifdef LIBUSB_GLOBAL_INCLUDE_FILE
28 #include LIBUSB_GLOBAL_INCLUDE_FILE
29 #else
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include <time.h>
34 #include <sys/param.h>
35 #include <sys/queue.h>
36 #endif
37
38 #include "libusb20.h"
39 #include "libusb20_desc.h"
40 #include "libusb20_int.h"
41
42 static const uint32_t libusb20_me_encode_empty[2]; /* dummy */
43
44 LIBUSB20_MAKE_STRUCT_FORMAT(LIBUSB20_DEVICE_DESC);
45 LIBUSB20_MAKE_STRUCT_FORMAT(LIBUSB20_ENDPOINT_DESC);
46 LIBUSB20_MAKE_STRUCT_FORMAT(LIBUSB20_INTERFACE_DESC);
47 LIBUSB20_MAKE_STRUCT_FORMAT(LIBUSB20_CONFIG_DESC);
48 LIBUSB20_MAKE_STRUCT_FORMAT(LIBUSB20_CONTROL_SETUP);
49 LIBUSB20_MAKE_STRUCT_FORMAT(LIBUSB20_SS_ENDPT_COMP_DESC);
50 LIBUSB20_MAKE_STRUCT_FORMAT(LIBUSB20_USB_20_DEVCAP_DESC);
51 LIBUSB20_MAKE_STRUCT_FORMAT(LIBUSB20_SS_USB_DEVCAP_DESC);
52 LIBUSB20_MAKE_STRUCT_FORMAT(LIBUSB20_BOS_DESCRIPTOR);
53
54 /*------------------------------------------------------------------------*
55 * libusb20_parse_config_desc
56 *
57 * Return values:
58 * NULL: Out of memory.
59 * Else: A valid config structure pointer which must be passed to "free()"
60 *------------------------------------------------------------------------*/
61 struct libusb20_config *
62 libusb20_parse_config_desc(const void *config_desc)
63 {
64 struct libusb20_config *lub_config;
65 struct libusb20_interface *lub_interface;
66 struct libusb20_interface *lub_alt_interface;
67 struct libusb20_interface *last_if;
68 struct libusb20_endpoint *lub_endpoint;
69 struct libusb20_endpoint *last_ep;
70
71 struct libusb20_me_struct pcdesc;
72 const uint8_t *ptr;
73 uint32_t size;
74 uint16_t niface_no_alt;
75 uint16_t niface;
76 uint16_t nendpoint;
77 uint16_t iface_no;
78
79 ptr = config_desc;
80 if (ptr[1] != LIBUSB20_DT_CONFIG) {
81 return (NULL); /* not config descriptor */
82 }
83 /*
84 * The first "bInterfaceNumber" should never have the value 0xff.
85 * Then it is corrupt.
86 */
87 niface_no_alt = 0;
88 nendpoint = 0;
89 niface = 0;
90 iface_no = 0xFFFF;
91 ptr = NULL;
92
93 /* get "wTotalLength" and setup "pcdesc" */
94 pcdesc.ptr = LIBUSB20_ADD_BYTES(config_desc, 0);
95 pcdesc.len =
96 ((const uint8_t *)config_desc)[2] |
97 (((const uint8_t *)config_desc)[3] << 8);
98 pcdesc.type = LIBUSB20_ME_IS_RAW;
99
100 /* descriptor pre-scan */
101 while ((ptr = libusb20_desc_foreach(&pcdesc, ptr))) {
102 if (ptr[1] == LIBUSB20_DT_ENDPOINT) {
103 nendpoint++;
104 } else if ((ptr[1] == LIBUSB20_DT_INTERFACE) && (ptr[0] >= 4)) {
105 niface++;
106 /* check "bInterfaceNumber" */
107 if (ptr[2] != iface_no) {
108 iface_no = ptr[2];
109 niface_no_alt++;
110 }
111 }
112 }
113
114 /* sanity checking */
115 if (niface >= 256) {
116 return (NULL); /* corrupt */
117 }
118 if (nendpoint >= 256) {
119 return (NULL); /* corrupt */
120 }
121 size = sizeof(*lub_config) +
122 (niface * sizeof(*lub_interface)) +
123 (nendpoint * sizeof(*lub_endpoint)) +
124 pcdesc.len;
125
126 lub_config = malloc(size);
127 if (lub_config == NULL) {
128 return (NULL); /* out of memory */
129 }
130 /* make sure memory is initialised */
131 memset(lub_config, 0, size);
132
133 lub_interface = (void *)(lub_config + 1);
134 lub_alt_interface = (void *)(lub_interface + niface_no_alt);
135 lub_endpoint = (void *)(lub_interface + niface);
136
137 /*
138 * Make a copy of the config descriptor, so that the caller can free
139 * the inital config descriptor pointer!
140 */
141 ptr = (void *)(lub_endpoint + nendpoint);
142 memcpy(LIBUSB20_ADD_BYTES(ptr, 0), config_desc, pcdesc.len);
143 pcdesc.ptr = LIBUSB20_ADD_BYTES(ptr, 0);
144 config_desc = LIBUSB20_ADD_BYTES(ptr, 0);
145
146 /* init config structure */
147
148 ptr = config_desc;
149
150 LIBUSB20_INIT(LIBUSB20_CONFIG_DESC, &lub_config->desc);
151
152 if (libusb20_me_decode(ptr, ptr[0], &lub_config->desc)) {
153 /* ignore */
154 }
155 lub_config->num_interface = 0;
156 lub_config->interface = lub_interface;
157 lub_config->extra.ptr = LIBUSB20_ADD_BYTES(ptr, ptr[0]);
158 lub_config->extra.len = -ptr[0];
159 lub_config->extra.type = LIBUSB20_ME_IS_RAW;
160
161 /* reset states */
162 niface = 0;
163 iface_no = 0xFFFF;
164 ptr = NULL;
165 lub_interface--;
166 lub_endpoint--;
167 last_if = NULL;
168 last_ep = NULL;
169
170 /* descriptor pre-scan */
171 while ((ptr = libusb20_desc_foreach(&pcdesc, ptr))) {
172 if (ptr[1] == LIBUSB20_DT_ENDPOINT) {
173 if (last_if) {
174 lub_endpoint++;
175 last_ep = lub_endpoint;
176 last_if->num_endpoints++;
177
178 LIBUSB20_INIT(LIBUSB20_ENDPOINT_DESC, &last_ep->desc);
179
180 if (libusb20_me_decode(ptr, ptr[0], &last_ep->desc)) {
181 /* ignore */
182 }
183 last_ep->extra.ptr = LIBUSB20_ADD_BYTES(ptr, ptr[0]);
184 last_ep->extra.len = 0;
185 last_ep->extra.type = LIBUSB20_ME_IS_RAW;
186 } else {
187 lub_config->extra.len += ptr[0];
188 }
189
190 } else if ((ptr[1] == LIBUSB20_DT_INTERFACE) && (ptr[0] >= 4)) {
191 if (ptr[2] != iface_no) {
192 /* new interface */
193 iface_no = ptr[2];
194 lub_interface++;
195 lub_config->num_interface++;
196 last_if = lub_interface;
197 niface++;
198 } else {
199 /* one more alternate setting */
200 lub_interface->num_altsetting++;
201 last_if = lub_alt_interface;
202 lub_alt_interface++;
203 }
204
205 LIBUSB20_INIT(LIBUSB20_INTERFACE_DESC, &last_if->desc);
206
207 if (libusb20_me_decode(ptr, ptr[0], &last_if->desc)) {
208 /* ignore */
209 }
210 /*
211 * Sometimes USB devices have corrupt interface
212 * descriptors and we need to overwrite the provided
213 * interface number!
214 */
215 last_if->desc.bInterfaceNumber = niface - 1;
216 last_if->extra.ptr = LIBUSB20_ADD_BYTES(ptr, ptr[0]);
217 last_if->extra.len = 0;
218 last_if->extra.type = LIBUSB20_ME_IS_RAW;
219 last_if->endpoints = lub_endpoint + 1;
220 last_if->altsetting = lub_alt_interface;
221 last_if->num_altsetting = 0;
222 last_if->num_endpoints = 0;
223 last_ep = NULL;
224 } else {
225 /* unknown descriptor */
226 if (last_if) {
227 if (last_ep) {
228 last_ep->extra.len += ptr[0];
229 } else {
230 last_if->extra.len += ptr[0];
231 }
232 } else {
233 lub_config->extra.len += ptr[0];
234 }
235 }
236 }
237 return (lub_config);
238 }
239
240 /*------------------------------------------------------------------------*
241 * libusb20_desc_foreach
242 *
243 * Safe traversal of USB descriptors.
244 *
245 * Return values:
246 * NULL: End of descriptors
247 * Else: Pointer to next descriptor
248 *------------------------------------------------------------------------*/
249 const uint8_t *
250 libusb20_desc_foreach(const struct libusb20_me_struct *pdesc,
251 const uint8_t *psubdesc)
252 {
253 const uint8_t *start;
254 const uint8_t *end;
255 const uint8_t *desc_next;
256
257 /* be NULL safe */
258 if (pdesc == NULL)
259 return (NULL);
260
261 start = (const uint8_t *)pdesc->ptr;
262 end = LIBUSB20_ADD_BYTES(start, pdesc->len);
263
264 /* get start of next descriptor */
265 if (psubdesc == NULL)
266 psubdesc = start;
267 else
268 psubdesc = psubdesc + psubdesc[0];
269
270 /* check that the next USB descriptor is within the range */
271 if ((psubdesc < start) || (psubdesc >= end))
272 return (NULL); /* out of range, or EOD */
273
274 /* check start of the second next USB descriptor, if any */
275 desc_next = psubdesc + psubdesc[0];
276 if ((desc_next < start) || (desc_next > end))
277 return (NULL); /* out of range */
278
279 /* check minimum descriptor length */
280 if (psubdesc[0] < 3)
281 return (NULL); /* too short descriptor */
282
283 return (psubdesc); /* return start of next descriptor */
284 }
285
286 /*------------------------------------------------------------------------*
287 * libusb20_me_get_1 - safety wrapper to read out one byte
288 *------------------------------------------------------------------------*/
289 uint8_t
290 libusb20_me_get_1(const struct libusb20_me_struct *ie, uint16_t offset)
291 {
292 if (offset < ie->len) {
293 return (*((uint8_t *)LIBUSB20_ADD_BYTES(ie->ptr, offset)));
294 }
295 return (0);
296 }
297
298 /*------------------------------------------------------------------------*
299 * libusb20_me_get_2 - safety wrapper to read out one word
300 *------------------------------------------------------------------------*/
301 uint16_t
302 libusb20_me_get_2(const struct libusb20_me_struct *ie, uint16_t offset)
303 {
304 return (libusb20_me_get_1(ie, offset) |
305 (libusb20_me_get_1(ie, offset + 1) << 8));
306 }
307
308 /*------------------------------------------------------------------------*
309 * libusb20_me_encode - encode a message structure
310 *
311 * Description of parameters:
312 * "len" - maximum length of output buffer
313 * "ptr" - pointer to output buffer. If NULL, no data will be written
314 * "pd" - source structure
315 *
316 * Return values:
317 * 0..65535 - Number of bytes used, limited by the "len" input parameter.
318 *------------------------------------------------------------------------*/
319 uint16_t
320 libusb20_me_encode(void *ptr, uint16_t len, const void *pd)
321 {
322 const uint8_t *pf; /* pointer to format data */
323 uint8_t *buf; /* pointer to output buffer */
324
325 uint32_t pd_offset; /* decoded structure offset */
326 uint16_t len_old; /* old length */
327 uint16_t pd_count; /* decoded element count */
328 uint8_t me; /* message element */
329
330 /* initialise */
331
332 len_old = len;
333 buf = ptr;
334 pd_offset = sizeof(void *);
335 pf = (*((struct libusb20_me_format *const *)pd))->format;
336
337 /* scan */
338
339 while (1) {
340
341 /* get information element */
342
343 me = (pf[0]) & LIBUSB20_ME_MASK;
344 pd_count = pf[1] | (pf[2] << 8);
345 pf += 3;
346
347 /* encode the message element */
348
349 switch (me) {
350 case LIBUSB20_ME_INT8:
351 while (pd_count--) {
352 uint8_t temp;
353
354 if (len < 1) /* overflow */
355 goto done;
356 if (buf) {
357 temp = *((const uint8_t *)
358 LIBUSB20_ADD_BYTES(pd, pd_offset));
359 buf[0] = temp;
360 buf += 1;
361 }
362 pd_offset += 1;
363 len -= 1;
364 }
365 break;
366
367 case LIBUSB20_ME_INT16:
368 pd_offset = -((-pd_offset) & ~1); /* align */
369 while (pd_count--) {
370 uint16_t temp;
371
372 if (len < 2) /* overflow */
373 goto done;
374
375 if (buf) {
376 temp = *((const uint16_t *)
377 LIBUSB20_ADD_BYTES(pd, pd_offset));
378 buf[1] = (temp >> 8) & 0xFF;
379 buf[0] = temp & 0xFF;
380 buf += 2;
381 }
382 pd_offset += 2;
383 len -= 2;
384 }
385 break;
386
387 case LIBUSB20_ME_INT32:
388 pd_offset = -((-pd_offset) & ~3); /* align */
389 while (pd_count--) {
390 uint32_t temp;
391
392 if (len < 4) /* overflow */
393 goto done;
394 if (buf) {
395 temp = *((const uint32_t *)
396 LIBUSB20_ADD_BYTES(pd, pd_offset));
397 buf[3] = (temp >> 24) & 0xFF;
398 buf[2] = (temp >> 16) & 0xFF;
399 buf[1] = (temp >> 8) & 0xFF;
400 buf[0] = temp & 0xFF;
401 buf += 4;
402 }
403 pd_offset += 4;
404 len -= 4;
405 }
406 break;
407
408 case LIBUSB20_ME_INT64:
409 pd_offset = -((-pd_offset) & ~7); /* align */
410 while (pd_count--) {
411 uint64_t temp;
412
413 if (len < 8) /* overflow */
414 goto done;
415 if (buf) {
416
417 temp = *((const uint64_t *)
418 LIBUSB20_ADD_BYTES(pd, pd_offset));
419 buf[7] = (temp >> 56) & 0xFF;
420 buf[6] = (temp >> 48) & 0xFF;
421 buf[5] = (temp >> 40) & 0xFF;
422 buf[4] = (temp >> 32) & 0xFF;
423 buf[3] = (temp >> 24) & 0xFF;
424 buf[2] = (temp >> 16) & 0xFF;
425 buf[1] = (temp >> 8) & 0xFF;
426 buf[0] = temp & 0xFF;
427 buf += 8;
428 }
429 pd_offset += 8;
430 len -= 8;
431 }
432 break;
433
434 case LIBUSB20_ME_STRUCT:
435 pd_offset = -rounddown2(-pd_offset, LIBUSB20_ME_STRUCT_ALIGN); /* align */
436 while (pd_count--) {
437 void *src_ptr;
438 uint16_t src_len;
439 struct libusb20_me_struct *ps;
440
441 ps = LIBUSB20_ADD_BYTES(pd, pd_offset);
442
443 switch (ps->type) {
444 case LIBUSB20_ME_IS_RAW:
445 src_len = ps->len;
446 src_ptr = ps->ptr;
447 break;
448
449 case LIBUSB20_ME_IS_ENCODED:
450 if (ps->len == 0) {
451 /*
452 * Length is encoded
453 * in the data itself
454 * and should be
455 * correct:
456 */
457 ps->len = 0xFFFF;
458 }
459 src_len = libusb20_me_get_1(pd, 0);
460 src_ptr = LIBUSB20_ADD_BYTES(ps->ptr, 1);
461 if (src_len == 0xFF) {
462 /* length is escaped */
463 src_len = libusb20_me_get_2(pd, 1);
464 src_ptr =
465 LIBUSB20_ADD_BYTES(ps->ptr, 3);
466 }
467 break;
468
469 case LIBUSB20_ME_IS_DECODED:
470 /* reserve 3 length bytes */
471 src_len = libusb20_me_encode(NULL,
472 0xFFFF - 3, ps->ptr);
473 src_ptr = NULL;
474 break;
475
476 default: /* empty structure */
477 src_len = 0;
478 src_ptr = NULL;
479 break;
480 }
481
482 if (src_len > 0xFE) {
483 if (src_len > (0xFFFF - 3))
484 /* overflow */
485 goto done;
486
487 if (len < (src_len + 3))
488 /* overflow */
489 goto done;
490
491 if (buf) {
492 buf[0] = 0xFF;
493 buf[1] = (src_len & 0xFF);
494 buf[2] = (src_len >> 8) & 0xFF;
495 buf += 3;
496 }
497 len -= (src_len + 3);
498 } else {
499 if (len < (src_len + 1))
500 /* overflow */
501 goto done;
502
503 if (buf) {
504 buf[0] = (src_len & 0xFF);
505 buf += 1;
506 }
507 len -= (src_len + 1);
508 }
509
510 /* check for buffer and non-zero length */
511
512 if (buf && src_len) {
513 if (ps->type == LIBUSB20_ME_IS_DECODED) {
514 /*
515 * Repeat encode
516 * procedure - we have
517 * room for the
518 * complete structure:
519 */
520 uint16_t dummy;
521
522 dummy = libusb20_me_encode(buf,
523 0xFFFF - 3, ps->ptr);
524 } else {
525 bcopy(src_ptr, buf, src_len);
526 }
527 buf += src_len;
528 }
529 pd_offset += sizeof(struct libusb20_me_struct);
530 }
531 break;
532
533 default:
534 goto done;
535 }
536 }
537 done:
538 return (len_old - len);
539 }
540
541 /*------------------------------------------------------------------------*
542 * libusb20_me_decode - decode a message into a decoded structure
543 *
544 * Description of parameters:
545 * "ptr" - message pointer
546 * "len" - message length
547 * "pd" - pointer to decoded structure
548 *
549 * Returns:
550 * "0..65535" - number of bytes decoded, limited by "len"
551 *------------------------------------------------------------------------*/
552 uint16_t
553 libusb20_me_decode(const void *ptr, uint16_t len, void *pd)
554 {
555 const uint8_t *pf; /* pointer to format data */
556 const uint8_t *buf; /* pointer to input buffer */
557
558 uint32_t pd_offset; /* decoded structure offset */
559 uint16_t len_old; /* old length */
560 uint16_t pd_count; /* decoded element count */
561 uint8_t me; /* message element */
562
563 /* initialise */
564
565 len_old = len;
566 buf = ptr;
567 pd_offset = sizeof(void *);
568 pf = (*((struct libusb20_me_format **)pd))->format;
569
570 /* scan */
571
572 while (1) {
573
574 /* get information element */
575
576 me = (pf[0]) & LIBUSB20_ME_MASK;
577 pd_count = pf[1] | (pf[2] << 8);
578 pf += 3;
579
580 /* decode the message element by type */
581
582 switch (me) {
583 case LIBUSB20_ME_INT8:
584 while (pd_count--) {
585 uint8_t temp;
586
587 if (len < 1) {
588 len = 0;
589 temp = 0;
590 } else {
591 len -= 1;
592 temp = buf[0];
593 buf++;
594 }
595 *((uint8_t *)LIBUSB20_ADD_BYTES(pd,
596 pd_offset)) = temp;
597 pd_offset += 1;
598 }
599 break;
600
601 case LIBUSB20_ME_INT16:
602 pd_offset = -((-pd_offset) & ~1); /* align */
603 while (pd_count--) {
604 uint16_t temp;
605
606 if (len < 2) {
607 len = 0;
608 temp = 0;
609 } else {
610 len -= 2;
611 temp = buf[1] << 8;
612 temp |= buf[0];
613 buf += 2;
614 }
615 *((uint16_t *)LIBUSB20_ADD_BYTES(pd,
616 pd_offset)) = temp;
617 pd_offset += 2;
618 }
619 break;
620
621 case LIBUSB20_ME_INT32:
622 pd_offset = -((-pd_offset) & ~3); /* align */
623 while (pd_count--) {
624 uint32_t temp;
625
626 if (len < 4) {
627 len = 0;
628 temp = 0;
629 } else {
630 len -= 4;
631 temp = buf[3] << 24;
632 temp |= buf[2] << 16;
633 temp |= buf[1] << 8;
634 temp |= buf[0];
635 buf += 4;
636 }
637
638 *((uint32_t *)LIBUSB20_ADD_BYTES(pd,
639 pd_offset)) = temp;
640 pd_offset += 4;
641 }
642 break;
643
644 case LIBUSB20_ME_INT64:
645 pd_offset = -((-pd_offset) & ~7); /* align */
646 while (pd_count--) {
647 uint64_t temp;
648
649 if (len < 8) {
650 len = 0;
651 temp = 0;
652 } else {
653 len -= 8;
654 temp = ((uint64_t)buf[7]) << 56;
655 temp |= ((uint64_t)buf[6]) << 48;
656 temp |= ((uint64_t)buf[5]) << 40;
657 temp |= ((uint64_t)buf[4]) << 32;
658 temp |= buf[3] << 24;
659 temp |= buf[2] << 16;
660 temp |= buf[1] << 8;
661 temp |= buf[0];
662 buf += 8;
663 }
664
665 *((uint64_t *)LIBUSB20_ADD_BYTES(pd,
666 pd_offset)) = temp;
667 pd_offset += 8;
668 }
669 break;
670
671 case LIBUSB20_ME_STRUCT:
672 pd_offset = -rounddown2(-pd_offset, LIBUSB20_ME_STRUCT_ALIGN); /* align */
673 while (pd_count--) {
674 uint16_t temp;
675 uint16_t dummy;
676 struct libusb20_me_struct *ps;
677
678 ps = LIBUSB20_ADD_BYTES(pd, pd_offset);
679
680 if (ps->type == LIBUSB20_ME_IS_ENCODED) {
681 /*
682 * Pre-store a de-constified
683 * pointer to the raw
684 * structure:
685 */
686 ps->ptr = LIBUSB20_ADD_BYTES(buf, 0);
687
688 /*
689 * Get the correct number of
690 * length bytes:
691 */
692 if (len != 0) {
693 if (buf[0] == 0xFF) {
694 ps->len = 3;
695 } else {
696 ps->len = 1;
697 }
698 } else {
699 ps->len = 0;
700 }
701 }
702 /* get the structure length */
703
704 if (len != 0) {
705 if (buf[0] == 0xFF) {
706 if (len < 3) {
707 len = 0;
708 temp = 0;
709 } else {
710 len -= 3;
711 temp = buf[1] |
712 (buf[2] << 8);
713 buf += 3;
714 }
715 } else {
716 len -= 1;
717 temp = buf[0];
718 buf += 1;
719 }
720 } else {
721 len = 0;
722 temp = 0;
723 }
724 /* check for invalid length */
725
726 if (temp > len) {
727 len = 0;
728 temp = 0;
729 }
730 /* check wanted structure type */
731
732 switch (ps->type) {
733 case LIBUSB20_ME_IS_ENCODED:
734 /* check for zero length */
735 if (temp == 0) {
736 /*
737 * The pointer must
738 * be valid:
739 */
740 ps->ptr = LIBUSB20_ADD_BYTES(
741 libusb20_me_encode_empty, 0);
742 ps->len = 1;
743 } else {
744 ps->len += temp;
745 }
746 break;
747
748 case LIBUSB20_ME_IS_RAW:
749 /* update length and pointer */
750 ps->len = temp;
751 ps->ptr = LIBUSB20_ADD_BYTES(buf, 0);
752 break;
753
754 case LIBUSB20_ME_IS_EMPTY:
755 case LIBUSB20_ME_IS_DECODED:
756 /* check for non-zero length */
757 if (temp != 0) {
758 /* update type */
759 ps->type = LIBUSB20_ME_IS_DECODED;
760 ps->len = 0;
761 /*
762 * Recursivly decode
763 * the next structure
764 */
765 dummy = libusb20_me_decode(buf,
766 temp, ps->ptr);
767 } else {
768 /* update type */
769 ps->type = LIBUSB20_ME_IS_EMPTY;
770 ps->len = 0;
771 }
772 break;
773
774 default:
775 /*
776 * nothing to do - should
777 * not happen
778 */
779 ps->ptr = NULL;
780 ps->len = 0;
781 break;
782 }
783 buf += temp;
784 len -= temp;
785 pd_offset += sizeof(struct libusb20_me_struct);
786 }
787 break;
788
789 default:
790 goto done;
791 }
792 }
793 done:
794 return (len_old - len);
795 }
DragonFly BSD