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10#ifdef __KERNEL__
11#include <linux/kernel.h>
12#else
13#include <stdio.h>
14#endif
15#include <linux/netfilter/nf_conntrack_h323_asn1.h>
16
17
18#ifndef H323_TRACE
19#define H323_TRACE 0
20#endif
21
22#if H323_TRACE
23#define TAB_SIZE 4
24#define IFTHEN(cond, act) if(cond){act;}
25#ifdef __KERNEL__
26#define PRINT printk
27#else
28#define PRINT printf
29#endif
30#define FNAME(name) name,
31#else
32#define IFTHEN(cond, act)
33#define PRINT(fmt, args...)
34#define FNAME(name)
35#endif
36
37
38#define NUL 0
39#define BOOL 1
40#define OID 2
41#define INT 3
42#define ENUM 4
43#define BITSTR 5
44#define NUMSTR 6
45#define NUMDGT 6
46#define TBCDSTR 6
47#define OCTSTR 7
48#define PRTSTR 7
49#define IA5STR 7
50#define GENSTR 7
51#define BMPSTR 8
52#define SEQ 9
53#define SET 9
54#define SEQOF 10
55#define SETOF 10
56#define CHOICE 11
57
58
59#define FIXD 0
60
61#define BYTE 9
62#define WORD 10
63#define CONS 11
64#define SEMI 12
65#define UNCO 13
66
67
68#define SKIP 0
69#define STOP 1
70#define DECODE 2
71#define EXT 4
72#define OPEN 8
73#define OPT 16
74
75
76
77typedef struct field_t {
78#if H323_TRACE
79 char *name;
80#endif
81 unsigned char type;
82 unsigned char sz;
83 unsigned char lb;
84 unsigned char ub;
85 unsigned short attr;
86 unsigned short offset;
87 const struct field_t *fields;
88} field_t;
89
90
91struct bitstr {
92 unsigned char *buf;
93 unsigned char *beg;
94 unsigned char *end;
95 unsigned char *cur;
96 unsigned int bit;
97};
98
99
100#define INC_BIT(bs) if((++(bs)->bit)>7){(bs)->cur++;(bs)->bit=0;}
101#define INC_BITS(bs,b) if(((bs)->bit+=(b))>7){(bs)->cur+=(bs)->bit>>3;(bs)->bit&=7;}
102#define BYTE_ALIGN(bs) if((bs)->bit){(bs)->cur++;(bs)->bit=0;}
103static unsigned int get_len(struct bitstr *bs);
104static unsigned int get_bit(struct bitstr *bs);
105static unsigned int get_bits(struct bitstr *bs, unsigned int b);
106static unsigned int get_bitmap(struct bitstr *bs, unsigned int b);
107static unsigned int get_uint(struct bitstr *bs, int b);
108
109
110static int decode_nul(struct bitstr *bs, const struct field_t *f, char *base, int level);
111static int decode_bool(struct bitstr *bs, const struct field_t *f, char *base, int level);
112static int decode_oid(struct bitstr *bs, const struct field_t *f, char *base, int level);
113static int decode_int(struct bitstr *bs, const struct field_t *f, char *base, int level);
114static int decode_enum(struct bitstr *bs, const struct field_t *f, char *base, int level);
115static int decode_bitstr(struct bitstr *bs, const struct field_t *f, char *base, int level);
116static int decode_numstr(struct bitstr *bs, const struct field_t *f, char *base, int level);
117static int decode_octstr(struct bitstr *bs, const struct field_t *f, char *base, int level);
118static int decode_bmpstr(struct bitstr *bs, const struct field_t *f, char *base, int level);
119static int decode_seq(struct bitstr *bs, const struct field_t *f, char *base, int level);
120static int decode_seqof(struct bitstr *bs, const struct field_t *f, char *base, int level);
121static int decode_choice(struct bitstr *bs, const struct field_t *f, char *base, int level);
122
123
124typedef int (*decoder_t)(struct bitstr *, const struct field_t *, char *, int);
125static const decoder_t Decoders[] = {
126 decode_nul,
127 decode_bool,
128 decode_oid,
129 decode_int,
130 decode_enum,
131 decode_bitstr,
132 decode_numstr,
133 decode_octstr,
134 decode_bmpstr,
135 decode_seq,
136 decode_seqof,
137 decode_choice,
138};
139
140
141
142
143#include "nf_conntrack_h323_types.c"
144
145
146
147
148
149
150static unsigned int get_len(struct bitstr *bs)
151{
152 unsigned int v;
153
154 v = *bs->cur++;
155
156 if (v & 0x80) {
157 v &= 0x3f;
158 v <<= 8;
159 v += *bs->cur++;
160 }
161
162 return v;
163}
164
165static int nf_h323_error_boundary(struct bitstr *bs, size_t bytes, size_t bits)
166{
167 bits += bs->bit;
168 bytes += bits / BITS_PER_BYTE;
169 if (bits % BITS_PER_BYTE > 0)
170 bytes++;
171
172 if (bs->cur + bytes > bs->end)
173 return 1;
174
175 return 0;
176}
177
178static unsigned int get_bit(struct bitstr *bs)
179{
180 unsigned int b = (*bs->cur) & (0x80 >> bs->bit);
181
182 INC_BIT(bs);
183
184 return b;
185}
186
187
188static unsigned int get_bits(struct bitstr *bs, unsigned int b)
189{
190 unsigned int v, l;
191
192 v = (*bs->cur) & (0xffU >> bs->bit);
193 l = b + bs->bit;
194
195 if (l < 8) {
196 v >>= 8 - l;
197 bs->bit = l;
198 } else if (l == 8) {
199 bs->cur++;
200 bs->bit = 0;
201 } else {
202
203 v <<= 8;
204 v += *(++bs->cur);
205 v >>= 16 - l;
206 bs->bit = l - 8;
207 }
208
209 return v;
210}
211
212
213static unsigned int get_bitmap(struct bitstr *bs, unsigned int b)
214{
215 unsigned int v, l, shift, bytes;
216
217 if (!b)
218 return 0;
219
220 l = bs->bit + b;
221
222 if (l < 8) {
223 v = (unsigned int)(*bs->cur) << (bs->bit + 24);
224 bs->bit = l;
225 } else if (l == 8) {
226 v = (unsigned int)(*bs->cur++) << (bs->bit + 24);
227 bs->bit = 0;
228 } else {
229 for (bytes = l >> 3, shift = 24, v = 0; bytes;
230 bytes--, shift -= 8)
231 v |= (unsigned int)(*bs->cur++) << shift;
232
233 if (l < 32) {
234 v |= (unsigned int)(*bs->cur) << shift;
235 v <<= bs->bit;
236 } else if (l > 32) {
237 v <<= bs->bit;
238 v |= (*bs->cur) >> (8 - bs->bit);
239 }
240
241 bs->bit = l & 0x7;
242 }
243
244 v &= 0xffffffff << (32 - b);
245
246 return v;
247}
248
249
250
251
252static unsigned int get_uint(struct bitstr *bs, int b)
253{
254 unsigned int v = 0;
255
256 switch (b) {
257 case 4:
258 v |= *bs->cur++;
259 v <<= 8;
260 fallthrough;
261 case 3:
262 v |= *bs->cur++;
263 v <<= 8;
264 fallthrough;
265 case 2:
266 v |= *bs->cur++;
267 v <<= 8;
268 fallthrough;
269 case 1:
270 v |= *bs->cur++;
271 break;
272 }
273 return v;
274}
275
276static int decode_nul(struct bitstr *bs, const struct field_t *f,
277 char *base, int level)
278{
279 PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name);
280
281 return H323_ERROR_NONE;
282}
283
284static int decode_bool(struct bitstr *bs, const struct field_t *f,
285 char *base, int level)
286{
287 PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name);
288
289 INC_BIT(bs);
290 if (nf_h323_error_boundary(bs, 0, 0))
291 return H323_ERROR_BOUND;
292 return H323_ERROR_NONE;
293}
294
295static int decode_oid(struct bitstr *bs, const struct field_t *f,
296 char *base, int level)
297{
298 int len;
299
300 PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name);
301
302 BYTE_ALIGN(bs);
303 if (nf_h323_error_boundary(bs, 1, 0))
304 return H323_ERROR_BOUND;
305
306 len = *bs->cur++;
307 bs->cur += len;
308 if (nf_h323_error_boundary(bs, 0, 0))
309 return H323_ERROR_BOUND;
310
311 return H323_ERROR_NONE;
312}
313
314static int decode_int(struct bitstr *bs, const struct field_t *f,
315 char *base, int level)
316{
317 unsigned int len;
318
319 PRINT("%*.s%s", level * TAB_SIZE, " ", f->name);
320
321 switch (f->sz) {
322 case BYTE:
323 BYTE_ALIGN(bs);
324 bs->cur++;
325 break;
326 case WORD:
327 BYTE_ALIGN(bs);
328 bs->cur += 2;
329 break;
330 case CONS:
331 if (nf_h323_error_boundary(bs, 0, 2))
332 return H323_ERROR_BOUND;
333 len = get_bits(bs, 2) + 1;
334 BYTE_ALIGN(bs);
335 if (base && (f->attr & DECODE)) {
336 unsigned int v = get_uint(bs, len) + f->lb;
337 PRINT(" = %u", v);
338 *((unsigned int *)(base + f->offset)) = v;
339 }
340 bs->cur += len;
341 break;
342 case UNCO:
343 BYTE_ALIGN(bs);
344 if (nf_h323_error_boundary(bs, 2, 0))
345 return H323_ERROR_BOUND;
346 len = get_len(bs);
347 bs->cur += len;
348 break;
349 default:
350 INC_BITS(bs, f->sz);
351 break;
352 }
353
354 PRINT("\n");
355
356 if (nf_h323_error_boundary(bs, 0, 0))
357 return H323_ERROR_BOUND;
358 return H323_ERROR_NONE;
359}
360
361static int decode_enum(struct bitstr *bs, const struct field_t *f,
362 char *base, int level)
363{
364 PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name);
365
366 if ((f->attr & EXT) && get_bit(bs)) {
367 INC_BITS(bs, 7);
368 } else {
369 INC_BITS(bs, f->sz);
370 }
371
372 if (nf_h323_error_boundary(bs, 0, 0))
373 return H323_ERROR_BOUND;
374 return H323_ERROR_NONE;
375}
376
377static int decode_bitstr(struct bitstr *bs, const struct field_t *f,
378 char *base, int level)
379{
380 unsigned int len;
381
382 PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name);
383
384 BYTE_ALIGN(bs);
385 switch (f->sz) {
386 case FIXD:
387 len = f->lb;
388 break;
389 case WORD:
390 if (nf_h323_error_boundary(bs, 2, 0))
391 return H323_ERROR_BOUND;
392 len = (*bs->cur++) << 8;
393 len += (*bs->cur++) + f->lb;
394 break;
395 case SEMI:
396 if (nf_h323_error_boundary(bs, 2, 0))
397 return H323_ERROR_BOUND;
398 len = get_len(bs);
399 break;
400 default:
401 len = 0;
402 break;
403 }
404
405 bs->cur += len >> 3;
406 bs->bit = len & 7;
407
408 if (nf_h323_error_boundary(bs, 0, 0))
409 return H323_ERROR_BOUND;
410 return H323_ERROR_NONE;
411}
412
413static int decode_numstr(struct bitstr *bs, const struct field_t *f,
414 char *base, int level)
415{
416 unsigned int len;
417
418 PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name);
419
420
421 if (nf_h323_error_boundary(bs, 0, f->sz))
422 return H323_ERROR_BOUND;
423 len = get_bits(bs, f->sz) + f->lb;
424
425 BYTE_ALIGN(bs);
426 INC_BITS(bs, (len << 2));
427
428 if (nf_h323_error_boundary(bs, 0, 0))
429 return H323_ERROR_BOUND;
430 return H323_ERROR_NONE;
431}
432
433static int decode_octstr(struct bitstr *bs, const struct field_t *f,
434 char *base, int level)
435{
436 unsigned int len;
437
438 PRINT("%*.s%s", level * TAB_SIZE, " ", f->name);
439
440 switch (f->sz) {
441 case FIXD:
442 if (f->lb > 2) {
443 BYTE_ALIGN(bs);
444 if (base && (f->attr & DECODE)) {
445
446 IFTHEN(f->lb == 4,
447 PRINT(" = %d.%d.%d.%d:%d",
448 bs->cur[0], bs->cur[1],
449 bs->cur[2], bs->cur[3],
450 bs->cur[4] * 256 + bs->cur[5]));
451 *((unsigned int *)(base + f->offset)) =
452 bs->cur - bs->buf;
453 }
454 }
455 len = f->lb;
456 break;
457 case BYTE:
458 BYTE_ALIGN(bs);
459 if (nf_h323_error_boundary(bs, 1, 0))
460 return H323_ERROR_BOUND;
461 len = (*bs->cur++) + f->lb;
462 break;
463 case SEMI:
464 BYTE_ALIGN(bs);
465 if (nf_h323_error_boundary(bs, 2, 0))
466 return H323_ERROR_BOUND;
467 len = get_len(bs) + f->lb;
468 break;
469 default:
470 if (nf_h323_error_boundary(bs, 0, f->sz))
471 return H323_ERROR_BOUND;
472 len = get_bits(bs, f->sz) + f->lb;
473 BYTE_ALIGN(bs);
474 break;
475 }
476
477 bs->cur += len;
478
479 PRINT("\n");
480
481 if (nf_h323_error_boundary(bs, 0, 0))
482 return H323_ERROR_BOUND;
483 return H323_ERROR_NONE;
484}
485
486static int decode_bmpstr(struct bitstr *bs, const struct field_t *f,
487 char *base, int level)
488{
489 unsigned int len;
490
491 PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name);
492
493 switch (f->sz) {
494 case BYTE:
495 BYTE_ALIGN(bs);
496 if (nf_h323_error_boundary(bs, 1, 0))
497 return H323_ERROR_BOUND;
498 len = (*bs->cur++) + f->lb;
499 break;
500 default:
501 if (nf_h323_error_boundary(bs, 0, f->sz))
502 return H323_ERROR_BOUND;
503 len = get_bits(bs, f->sz) + f->lb;
504 BYTE_ALIGN(bs);
505 break;
506 }
507
508 bs->cur += len << 1;
509
510 if (nf_h323_error_boundary(bs, 0, 0))
511 return H323_ERROR_BOUND;
512 return H323_ERROR_NONE;
513}
514
515static int decode_seq(struct bitstr *bs, const struct field_t *f,
516 char *base, int level)
517{
518 unsigned int ext, bmp, i, opt, len = 0, bmp2, bmp2_len;
519 int err;
520 const struct field_t *son;
521 unsigned char *beg = NULL;
522
523 PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name);
524
525
526 base = (base && (f->attr & DECODE)) ? base + f->offset : NULL;
527
528
529 if (nf_h323_error_boundary(bs, 0, 1))
530 return H323_ERROR_BOUND;
531 ext = (f->attr & EXT) ? get_bit(bs) : 0;
532
533
534 if (nf_h323_error_boundary(bs, 0, f->sz))
535 return H323_ERROR_BOUND;
536 bmp = get_bitmap(bs, f->sz);
537 if (base)
538 *(unsigned int *)base = bmp;
539
540
541 for (i = opt = 0, son = f->fields; i < f->lb; i++, son++) {
542 if (son->attr & STOP) {
543 PRINT("%*.s%s\n", (level + 1) * TAB_SIZE, " ",
544 son->name);
545 return H323_ERROR_STOP;
546 }
547
548 if (son->attr & OPT) {
549 if (!((0x80000000U >> (opt++)) & bmp))
550 continue;
551 }
552
553
554 if (son->attr & OPEN) {
555 if (nf_h323_error_boundary(bs, 2, 0))
556 return H323_ERROR_BOUND;
557 len = get_len(bs);
558 if (nf_h323_error_boundary(bs, len, 0))
559 return H323_ERROR_BOUND;
560 if (!base || !(son->attr & DECODE)) {
561 PRINT("%*.s%s\n", (level + 1) * TAB_SIZE,
562 " ", son->name);
563 bs->cur += len;
564 continue;
565 }
566 beg = bs->cur;
567
568
569 if ((err = (Decoders[son->type]) (bs, son, base,
570 level + 1)) <
571 H323_ERROR_NONE)
572 return err;
573
574 bs->cur = beg + len;
575 bs->bit = 0;
576 } else if ((err = (Decoders[son->type]) (bs, son, base,
577 level + 1)) <
578 H323_ERROR_NONE)
579 return err;
580 }
581
582
583 if (!ext)
584 return H323_ERROR_NONE;
585
586
587 if (nf_h323_error_boundary(bs, 0, 7))
588 return H323_ERROR_BOUND;
589 bmp2_len = get_bits(bs, 7) + 1;
590 if (nf_h323_error_boundary(bs, 0, bmp2_len))
591 return H323_ERROR_BOUND;
592 bmp2 = get_bitmap(bs, bmp2_len);
593 bmp |= bmp2 >> f->sz;
594 if (base)
595 *(unsigned int *)base = bmp;
596 BYTE_ALIGN(bs);
597
598
599 for (opt = 0; opt < bmp2_len; opt++, i++, son++) {
600
601 if (i >= f->ub) {
602 if (nf_h323_error_boundary(bs, 2, 0))
603 return H323_ERROR_BOUND;
604 len = get_len(bs);
605 if (nf_h323_error_boundary(bs, len, 0))
606 return H323_ERROR_BOUND;
607 bs->cur += len;
608 continue;
609 }
610
611 if (son->attr & STOP) {
612 PRINT("%*.s%s\n", (level + 1) * TAB_SIZE, " ",
613 son->name);
614 return H323_ERROR_STOP;
615 }
616
617 if (!((0x80000000 >> opt) & bmp2))
618 continue;
619
620 if (nf_h323_error_boundary(bs, 2, 0))
621 return H323_ERROR_BOUND;
622 len = get_len(bs);
623 if (nf_h323_error_boundary(bs, len, 0))
624 return H323_ERROR_BOUND;
625 if (!base || !(son->attr & DECODE)) {
626 PRINT("%*.s%s\n", (level + 1) * TAB_SIZE, " ",
627 son->name);
628 bs->cur += len;
629 continue;
630 }
631 beg = bs->cur;
632
633 if ((err = (Decoders[son->type]) (bs, son, base,
634 level + 1)) <
635 H323_ERROR_NONE)
636 return err;
637
638 bs->cur = beg + len;
639 bs->bit = 0;
640 }
641 return H323_ERROR_NONE;
642}
643
644static int decode_seqof(struct bitstr *bs, const struct field_t *f,
645 char *base, int level)
646{
647 unsigned int count, effective_count = 0, i, len = 0;
648 int err;
649 const struct field_t *son;
650 unsigned char *beg = NULL;
651
652 PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name);
653
654
655 base = (base && (f->attr & DECODE)) ? base + f->offset : NULL;
656
657
658 switch (f->sz) {
659 case BYTE:
660 BYTE_ALIGN(bs);
661 if (nf_h323_error_boundary(bs, 1, 0))
662 return H323_ERROR_BOUND;
663 count = *bs->cur++;
664 break;
665 case WORD:
666 BYTE_ALIGN(bs);
667 if (nf_h323_error_boundary(bs, 2, 0))
668 return H323_ERROR_BOUND;
669 count = *bs->cur++;
670 count <<= 8;
671 count += *bs->cur++;
672 break;
673 case SEMI:
674 BYTE_ALIGN(bs);
675 if (nf_h323_error_boundary(bs, 2, 0))
676 return H323_ERROR_BOUND;
677 count = get_len(bs);
678 break;
679 default:
680 if (nf_h323_error_boundary(bs, 0, f->sz))
681 return H323_ERROR_BOUND;
682 count = get_bits(bs, f->sz);
683 break;
684 }
685 count += f->lb;
686
687
688 if (base) {
689 effective_count = count > f->ub ? f->ub : count;
690 *(unsigned int *)base = effective_count;
691 base += sizeof(unsigned int);
692 }
693
694
695 son = f->fields;
696 if (base)
697 base -= son->offset;
698 for (i = 0; i < count; i++) {
699 if (son->attr & OPEN) {
700 BYTE_ALIGN(bs);
701 if (nf_h323_error_boundary(bs, 2, 0))
702 return H323_ERROR_BOUND;
703 len = get_len(bs);
704 if (nf_h323_error_boundary(bs, len, 0))
705 return H323_ERROR_BOUND;
706 if (!base || !(son->attr & DECODE)) {
707 PRINT("%*.s%s\n", (level + 1) * TAB_SIZE,
708 " ", son->name);
709 bs->cur += len;
710 continue;
711 }
712 beg = bs->cur;
713
714 if ((err = (Decoders[son->type]) (bs, son,
715 i <
716 effective_count ?
717 base : NULL,
718 level + 1)) <
719 H323_ERROR_NONE)
720 return err;
721
722 bs->cur = beg + len;
723 bs->bit = 0;
724 } else
725 if ((err = (Decoders[son->type]) (bs, son,
726 i <
727 effective_count ?
728 base : NULL,
729 level + 1)) <
730 H323_ERROR_NONE)
731 return err;
732
733 if (base)
734 base += son->offset;
735 }
736
737 return H323_ERROR_NONE;
738}
739
740static int decode_choice(struct bitstr *bs, const struct field_t *f,
741 char *base, int level)
742{
743 unsigned int type, ext, len = 0;
744 int err;
745 const struct field_t *son;
746 unsigned char *beg = NULL;
747
748 PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name);
749
750
751 base = (base && (f->attr & DECODE)) ? base + f->offset : NULL;
752
753
754 if (nf_h323_error_boundary(bs, 0, 1))
755 return H323_ERROR_BOUND;
756 if ((f->attr & EXT) && get_bit(bs)) {
757 ext = 1;
758 if (nf_h323_error_boundary(bs, 0, 7))
759 return H323_ERROR_BOUND;
760 type = get_bits(bs, 7) + f->lb;
761 } else {
762 ext = 0;
763 if (nf_h323_error_boundary(bs, 0, f->sz))
764 return H323_ERROR_BOUND;
765 type = get_bits(bs, f->sz);
766 if (type >= f->lb)
767 return H323_ERROR_RANGE;
768 }
769
770
771 if (base)
772 *(unsigned int *)base = type;
773
774
775 if (type >= f->ub) {
776 BYTE_ALIGN(bs);
777 if (nf_h323_error_boundary(bs, 2, 0))
778 return H323_ERROR_BOUND;
779 len = get_len(bs);
780 if (nf_h323_error_boundary(bs, len, 0))
781 return H323_ERROR_BOUND;
782 bs->cur += len;
783 return H323_ERROR_NONE;
784 }
785
786
787 son = &f->fields[type];
788 if (son->attr & STOP) {
789 PRINT("%*.s%s\n", (level + 1) * TAB_SIZE, " ", son->name);
790 return H323_ERROR_STOP;
791 }
792
793 if (ext || (son->attr & OPEN)) {
794 BYTE_ALIGN(bs);
795 if (nf_h323_error_boundary(bs, len, 0))
796 return H323_ERROR_BOUND;
797 len = get_len(bs);
798 if (nf_h323_error_boundary(bs, len, 0))
799 return H323_ERROR_BOUND;
800 if (!base || !(son->attr & DECODE)) {
801 PRINT("%*.s%s\n", (level + 1) * TAB_SIZE, " ",
802 son->name);
803 bs->cur += len;
804 return H323_ERROR_NONE;
805 }
806 beg = bs->cur;
807
808 if ((err = (Decoders[son->type]) (bs, son, base, level + 1)) <
809 H323_ERROR_NONE)
810 return err;
811
812 bs->cur = beg + len;
813 bs->bit = 0;
814 } else if ((err = (Decoders[son->type]) (bs, son, base, level + 1)) <
815 H323_ERROR_NONE)
816 return err;
817
818 return H323_ERROR_NONE;
819}
820
821int DecodeRasMessage(unsigned char *buf, size_t sz, RasMessage *ras)
822{
823 static const struct field_t ras_message = {
824 FNAME("RasMessage") CHOICE, 5, 24, 32, DECODE | EXT,
825 0, _RasMessage
826 };
827 struct bitstr bs;
828
829 bs.buf = bs.beg = bs.cur = buf;
830 bs.end = buf + sz;
831 bs.bit = 0;
832
833 return decode_choice(&bs, &ras_message, (char *) ras, 0);
834}
835
836static int DecodeH323_UserInformation(unsigned char *buf, unsigned char *beg,
837 size_t sz, H323_UserInformation *uuie)
838{
839 static const struct field_t h323_userinformation = {
840 FNAME("H323-UserInformation") SEQ, 1, 2, 2, DECODE | EXT,
841 0, _H323_UserInformation
842 };
843 struct bitstr bs;
844
845 bs.buf = buf;
846 bs.beg = bs.cur = beg;
847 bs.end = beg + sz;
848 bs.bit = 0;
849
850 return decode_seq(&bs, &h323_userinformation, (char *) uuie, 0);
851}
852
853int DecodeMultimediaSystemControlMessage(unsigned char *buf, size_t sz,
854 MultimediaSystemControlMessage *
855 mscm)
856{
857 static const struct field_t multimediasystemcontrolmessage = {
858 FNAME("MultimediaSystemControlMessage") CHOICE, 2, 4, 4,
859 DECODE | EXT, 0, _MultimediaSystemControlMessage
860 };
861 struct bitstr bs;
862
863 bs.buf = bs.beg = bs.cur = buf;
864 bs.end = buf + sz;
865 bs.bit = 0;
866
867 return decode_choice(&bs, &multimediasystemcontrolmessage,
868 (char *) mscm, 0);
869}
870
871int DecodeQ931(unsigned char *buf, size_t sz, Q931 *q931)
872{
873 unsigned char *p = buf;
874 int len;
875
876 if (!p || sz < 1)
877 return H323_ERROR_BOUND;
878
879
880 if (*p != 0x08) {
881 PRINT("Unknown Protocol Discriminator\n");
882 return H323_ERROR_RANGE;
883 }
884 p++;
885 sz--;
886
887
888 if (sz < 1)
889 return H323_ERROR_BOUND;
890 len = *p++;
891 sz--;
892 if (sz < len)
893 return H323_ERROR_BOUND;
894 p += len;
895 sz -= len;
896
897
898 if (sz < 2)
899 return H323_ERROR_BOUND;
900 q931->MessageType = *p++;
901 sz--;
902 PRINT("MessageType = %02X\n", q931->MessageType);
903 if (*p & 0x80) {
904 p++;
905 sz--;
906 }
907
908
909 while (sz > 0) {
910 if (*p == 0x7e) {
911 if (sz < 3)
912 break;
913 p++;
914 len = *p++ << 8;
915 len |= *p++;
916 sz -= 3;
917 if (sz < len)
918 break;
919 p++;
920 len--;
921 return DecodeH323_UserInformation(buf, p, len,
922 &q931->UUIE);
923 }
924 p++;
925 sz--;
926 if (sz < 1)
927 break;
928 len = *p++;
929 sz--;
930 if (sz < len)
931 break;
932 p += len;
933 sz -= len;
934 }
935
936 PRINT("Q.931 UUIE not found\n");
937
938 return H323_ERROR_BOUND;
939}
940
