Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 1 | /**************************************************************************** |
| 2 | * ip_conntrack_helper_h323_asn1.c - BER and PER decoding library for H.323 |
| 3 | * conntrack/NAT module. |
| 4 | * |
Jing Min Zhao | 7582e9d | 2006-05-03 23:19:59 -0700 | [diff] [blame] | 5 | * Copyright (c) 2006 by Jing Min Zhao <zhaojingmin@users.sourceforge.net> |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 6 | * |
| 7 | * This source code is licensed under General Public License version 2. |
| 8 | * |
| 9 | * See ip_conntrack_helper_h323_asn1.h for details. |
| 10 | * |
| 11 | ****************************************************************************/ |
| 12 | |
| 13 | #ifdef __KERNEL__ |
| 14 | #include <linux/kernel.h> |
| 15 | #else |
| 16 | #include <stdio.h> |
| 17 | #endif |
Patrick McHardy | f587de0 | 2006-12-02 22:08:46 -0800 | [diff] [blame] | 18 | #include <linux/netfilter/nf_conntrack_h323_asn1.h> |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 19 | |
| 20 | /* Trace Flag */ |
| 21 | #ifndef H323_TRACE |
| 22 | #define H323_TRACE 0 |
| 23 | #endif |
| 24 | |
| 25 | #if H323_TRACE |
| 26 | #define TAB_SIZE 4 |
| 27 | #define IFTHEN(cond, act) if(cond){act;} |
| 28 | #ifdef __KERNEL__ |
| 29 | #define PRINT printk |
| 30 | #else |
| 31 | #define PRINT printf |
| 32 | #endif |
| 33 | #define FNAME(name) name, |
| 34 | #else |
| 35 | #define IFTHEN(cond, act) |
| 36 | #define PRINT(fmt, args...) |
| 37 | #define FNAME(name) |
| 38 | #endif |
| 39 | |
| 40 | /* ASN.1 Types */ |
| 41 | #define NUL 0 |
| 42 | #define BOOL 1 |
| 43 | #define OID 2 |
| 44 | #define INT 3 |
| 45 | #define ENUM 4 |
| 46 | #define BITSTR 5 |
| 47 | #define NUMSTR 6 |
| 48 | #define NUMDGT 6 |
| 49 | #define TBCDSTR 6 |
| 50 | #define OCTSTR 7 |
| 51 | #define PRTSTR 7 |
| 52 | #define IA5STR 7 |
| 53 | #define GENSTR 7 |
| 54 | #define BMPSTR 8 |
| 55 | #define SEQ 9 |
| 56 | #define SET 9 |
| 57 | #define SEQOF 10 |
| 58 | #define SETOF 10 |
| 59 | #define CHOICE 11 |
| 60 | |
| 61 | /* Constraint Types */ |
| 62 | #define FIXD 0 |
| 63 | /* #define BITS 1-8 */ |
| 64 | #define BYTE 9 |
| 65 | #define WORD 10 |
| 66 | #define CONS 11 |
| 67 | #define SEMI 12 |
| 68 | #define UNCO 13 |
| 69 | |
| 70 | /* ASN.1 Type Attributes */ |
| 71 | #define SKIP 0 |
| 72 | #define STOP 1 |
| 73 | #define DECODE 2 |
| 74 | #define EXT 4 |
| 75 | #define OPEN 8 |
| 76 | #define OPT 16 |
| 77 | |
| 78 | |
| 79 | /* ASN.1 Field Structure */ |
| 80 | typedef struct field_t { |
| 81 | #if H323_TRACE |
| 82 | char *name; |
| 83 | #endif |
| 84 | unsigned char type; |
| 85 | unsigned char sz; |
| 86 | unsigned char lb; |
| 87 | unsigned char ub; |
| 88 | unsigned short attr; |
| 89 | unsigned short offset; |
Jan Engelhardt | 905e3e8 | 2008-01-31 04:50:05 -0800 | [diff] [blame] | 90 | const struct field_t *fields; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 91 | } field_t; |
| 92 | |
| 93 | /* Bit Stream */ |
| 94 | typedef struct { |
| 95 | unsigned char *buf; |
| 96 | unsigned char *beg; |
| 97 | unsigned char *end; |
| 98 | unsigned char *cur; |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 99 | unsigned int bit; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 100 | } bitstr_t; |
| 101 | |
| 102 | /* Tool Functions */ |
Jan Engelhardt | e79ec50 | 2007-12-17 22:44:06 -0800 | [diff] [blame] | 103 | #define INC_BIT(bs) if((++(bs)->bit)>7){(bs)->cur++;(bs)->bit=0;} |
| 104 | #define INC_BITS(bs,b) if(((bs)->bit+=(b))>7){(bs)->cur+=(bs)->bit>>3;(bs)->bit&=7;} |
| 105 | #define BYTE_ALIGN(bs) if((bs)->bit){(bs)->cur++;(bs)->bit=0;} |
| 106 | #define CHECK_BOUND(bs,n) if((bs)->cur+(n)>(bs)->end)return(H323_ERROR_BOUND) |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 107 | static unsigned int get_len(bitstr_t *bs); |
| 108 | static unsigned int get_bit(bitstr_t *bs); |
| 109 | static unsigned int get_bits(bitstr_t *bs, unsigned int b); |
| 110 | static unsigned int get_bitmap(bitstr_t *bs, unsigned int b); |
| 111 | static unsigned int get_uint(bitstr_t *bs, int b); |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 112 | |
| 113 | /* Decoder Functions */ |
Jan Engelhardt | 905e3e8 | 2008-01-31 04:50:05 -0800 | [diff] [blame] | 114 | static int decode_nul(bitstr_t *bs, const struct field_t *f, char *base, int level); |
| 115 | static int decode_bool(bitstr_t *bs, const struct field_t *f, char *base, int level); |
| 116 | static int decode_oid(bitstr_t *bs, const struct field_t *f, char *base, int level); |
| 117 | static int decode_int(bitstr_t *bs, const struct field_t *f, char *base, int level); |
| 118 | static int decode_enum(bitstr_t *bs, const struct field_t *f, char *base, int level); |
| 119 | static int decode_bitstr(bitstr_t *bs, const struct field_t *f, char *base, int level); |
| 120 | static int decode_numstr(bitstr_t *bs, const struct field_t *f, char *base, int level); |
| 121 | static int decode_octstr(bitstr_t *bs, const struct field_t *f, char *base, int level); |
| 122 | static int decode_bmpstr(bitstr_t *bs, const struct field_t *f, char *base, int level); |
| 123 | static int decode_seq(bitstr_t *bs, const struct field_t *f, char *base, int level); |
| 124 | static int decode_seqof(bitstr_t *bs, const struct field_t *f, char *base, int level); |
| 125 | static int decode_choice(bitstr_t *bs, const struct field_t *f, char *base, int level); |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 126 | |
| 127 | /* Decoder Functions Vector */ |
Jan Engelhardt | 905e3e8 | 2008-01-31 04:50:05 -0800 | [diff] [blame] | 128 | typedef int (*decoder_t)(bitstr_t *, const struct field_t *, char *, int); |
Stephen Hemminger | dc64d02 | 2008-01-31 04:09:00 -0800 | [diff] [blame] | 129 | static const decoder_t Decoders[] = { |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 130 | decode_nul, |
| 131 | decode_bool, |
| 132 | decode_oid, |
| 133 | decode_int, |
| 134 | decode_enum, |
| 135 | decode_bitstr, |
| 136 | decode_numstr, |
| 137 | decode_octstr, |
| 138 | decode_bmpstr, |
| 139 | decode_seq, |
| 140 | decode_seqof, |
| 141 | decode_choice, |
| 142 | }; |
| 143 | |
| 144 | /**************************************************************************** |
| 145 | * H.323 Types |
| 146 | ****************************************************************************/ |
Patrick McHardy | f587de0 | 2006-12-02 22:08:46 -0800 | [diff] [blame] | 147 | #include "nf_conntrack_h323_types.c" |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 148 | |
| 149 | /**************************************************************************** |
| 150 | * Functions |
| 151 | ****************************************************************************/ |
| 152 | /* Assume bs is aligned && v < 16384 */ |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 153 | static unsigned int get_len(bitstr_t *bs) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 154 | { |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 155 | unsigned int v; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 156 | |
| 157 | v = *bs->cur++; |
| 158 | |
| 159 | if (v & 0x80) { |
| 160 | v &= 0x3f; |
| 161 | v <<= 8; |
| 162 | v += *bs->cur++; |
| 163 | } |
| 164 | |
| 165 | return v; |
| 166 | } |
| 167 | |
| 168 | /****************************************************************************/ |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 169 | static unsigned int get_bit(bitstr_t *bs) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 170 | { |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 171 | unsigned int b = (*bs->cur) & (0x80 >> bs->bit); |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 172 | |
| 173 | INC_BIT(bs); |
| 174 | |
| 175 | return b; |
| 176 | } |
| 177 | |
| 178 | /****************************************************************************/ |
| 179 | /* Assume b <= 8 */ |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 180 | static unsigned int get_bits(bitstr_t *bs, unsigned int b) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 181 | { |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 182 | unsigned int v, l; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 183 | |
| 184 | v = (*bs->cur) & (0xffU >> bs->bit); |
| 185 | l = b + bs->bit; |
| 186 | |
| 187 | if (l < 8) { |
| 188 | v >>= 8 - l; |
| 189 | bs->bit = l; |
| 190 | } else if (l == 8) { |
| 191 | bs->cur++; |
| 192 | bs->bit = 0; |
| 193 | } else { /* l > 8 */ |
| 194 | |
| 195 | v <<= 8; |
| 196 | v += *(++bs->cur); |
| 197 | v >>= 16 - l; |
| 198 | bs->bit = l - 8; |
| 199 | } |
| 200 | |
| 201 | return v; |
| 202 | } |
| 203 | |
| 204 | /****************************************************************************/ |
| 205 | /* Assume b <= 32 */ |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 206 | static unsigned int get_bitmap(bitstr_t *bs, unsigned int b) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 207 | { |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 208 | unsigned int v, l, shift, bytes; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 209 | |
| 210 | if (!b) |
| 211 | return 0; |
| 212 | |
| 213 | l = bs->bit + b; |
| 214 | |
| 215 | if (l < 8) { |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 216 | v = (unsigned int)(*bs->cur) << (bs->bit + 24); |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 217 | bs->bit = l; |
| 218 | } else if (l == 8) { |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 219 | v = (unsigned int)(*bs->cur++) << (bs->bit + 24); |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 220 | bs->bit = 0; |
| 221 | } else { |
| 222 | for (bytes = l >> 3, shift = 24, v = 0; bytes; |
| 223 | bytes--, shift -= 8) |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 224 | v |= (unsigned int)(*bs->cur++) << shift; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 225 | |
| 226 | if (l < 32) { |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 227 | v |= (unsigned int)(*bs->cur) << shift; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 228 | v <<= bs->bit; |
| 229 | } else if (l > 32) { |
| 230 | v <<= bs->bit; |
| 231 | v |= (*bs->cur) >> (8 - bs->bit); |
| 232 | } |
| 233 | |
| 234 | bs->bit = l & 0x7; |
| 235 | } |
| 236 | |
| 237 | v &= 0xffffffff << (32 - b); |
| 238 | |
| 239 | return v; |
| 240 | } |
| 241 | |
| 242 | /**************************************************************************** |
| 243 | * Assume bs is aligned and sizeof(unsigned int) == 4 |
| 244 | ****************************************************************************/ |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 245 | static unsigned int get_uint(bitstr_t *bs, int b) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 246 | { |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 247 | unsigned int v = 0; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 248 | |
| 249 | switch (b) { |
| 250 | case 4: |
| 251 | v |= *bs->cur++; |
| 252 | v <<= 8; |
| 253 | case 3: |
| 254 | v |= *bs->cur++; |
| 255 | v <<= 8; |
| 256 | case 2: |
| 257 | v |= *bs->cur++; |
| 258 | v <<= 8; |
| 259 | case 1: |
| 260 | v |= *bs->cur++; |
| 261 | break; |
| 262 | } |
| 263 | return v; |
| 264 | } |
| 265 | |
| 266 | /****************************************************************************/ |
Jan Engelhardt | 905e3e8 | 2008-01-31 04:50:05 -0800 | [diff] [blame] | 267 | static int decode_nul(bitstr_t *bs, const struct field_t *f, |
| 268 | char *base, int level) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 269 | { |
| 270 | PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name); |
| 271 | |
| 272 | return H323_ERROR_NONE; |
| 273 | } |
| 274 | |
| 275 | /****************************************************************************/ |
Jan Engelhardt | 905e3e8 | 2008-01-31 04:50:05 -0800 | [diff] [blame] | 276 | static int decode_bool(bitstr_t *bs, const struct field_t *f, |
| 277 | char *base, int level) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 278 | { |
| 279 | PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name); |
| 280 | |
| 281 | INC_BIT(bs); |
| 282 | |
| 283 | CHECK_BOUND(bs, 0); |
| 284 | return H323_ERROR_NONE; |
| 285 | } |
| 286 | |
| 287 | /****************************************************************************/ |
Jan Engelhardt | 905e3e8 | 2008-01-31 04:50:05 -0800 | [diff] [blame] | 288 | static int decode_oid(bitstr_t *bs, const struct field_t *f, |
| 289 | char *base, int level) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 290 | { |
| 291 | int len; |
| 292 | |
| 293 | PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name); |
| 294 | |
| 295 | BYTE_ALIGN(bs); |
| 296 | CHECK_BOUND(bs, 1); |
| 297 | len = *bs->cur++; |
| 298 | bs->cur += len; |
| 299 | |
| 300 | CHECK_BOUND(bs, 0); |
| 301 | return H323_ERROR_NONE; |
| 302 | } |
| 303 | |
| 304 | /****************************************************************************/ |
Jan Engelhardt | 905e3e8 | 2008-01-31 04:50:05 -0800 | [diff] [blame] | 305 | static int decode_int(bitstr_t *bs, const struct field_t *f, |
| 306 | char *base, int level) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 307 | { |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 308 | unsigned int len; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 309 | |
| 310 | PRINT("%*.s%s", level * TAB_SIZE, " ", f->name); |
| 311 | |
| 312 | switch (f->sz) { |
| 313 | case BYTE: /* Range == 256 */ |
| 314 | BYTE_ALIGN(bs); |
| 315 | bs->cur++; |
| 316 | break; |
| 317 | case WORD: /* 257 <= Range <= 64K */ |
| 318 | BYTE_ALIGN(bs); |
| 319 | bs->cur += 2; |
| 320 | break; |
| 321 | case CONS: /* 64K < Range < 4G */ |
| 322 | len = get_bits(bs, 2) + 1; |
| 323 | BYTE_ALIGN(bs); |
| 324 | if (base && (f->attr & DECODE)) { /* timeToLive */ |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 325 | unsigned int v = get_uint(bs, len) + f->lb; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 326 | PRINT(" = %u", v); |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 327 | *((unsigned int *)(base + f->offset)) = v; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 328 | } |
| 329 | bs->cur += len; |
| 330 | break; |
| 331 | case UNCO: |
| 332 | BYTE_ALIGN(bs); |
| 333 | CHECK_BOUND(bs, 2); |
| 334 | len = get_len(bs); |
| 335 | bs->cur += len; |
| 336 | break; |
| 337 | default: /* 2 <= Range <= 255 */ |
| 338 | INC_BITS(bs, f->sz); |
| 339 | break; |
| 340 | } |
| 341 | |
| 342 | PRINT("\n"); |
| 343 | |
| 344 | CHECK_BOUND(bs, 0); |
| 345 | return H323_ERROR_NONE; |
| 346 | } |
| 347 | |
| 348 | /****************************************************************************/ |
Jan Engelhardt | 905e3e8 | 2008-01-31 04:50:05 -0800 | [diff] [blame] | 349 | static int decode_enum(bitstr_t *bs, const struct field_t *f, |
| 350 | char *base, int level) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 351 | { |
| 352 | PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name); |
| 353 | |
| 354 | if ((f->attr & EXT) && get_bit(bs)) { |
| 355 | INC_BITS(bs, 7); |
| 356 | } else { |
| 357 | INC_BITS(bs, f->sz); |
| 358 | } |
| 359 | |
| 360 | CHECK_BOUND(bs, 0); |
| 361 | return H323_ERROR_NONE; |
| 362 | } |
| 363 | |
| 364 | /****************************************************************************/ |
Jan Engelhardt | 905e3e8 | 2008-01-31 04:50:05 -0800 | [diff] [blame] | 365 | static int decode_bitstr(bitstr_t *bs, const struct field_t *f, |
| 366 | char *base, int level) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 367 | { |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 368 | unsigned int len; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 369 | |
| 370 | PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name); |
| 371 | |
| 372 | BYTE_ALIGN(bs); |
| 373 | switch (f->sz) { |
| 374 | case FIXD: /* fixed length > 16 */ |
| 375 | len = f->lb; |
| 376 | break; |
| 377 | case WORD: /* 2-byte length */ |
| 378 | CHECK_BOUND(bs, 2); |
| 379 | len = (*bs->cur++) << 8; |
| 380 | len += (*bs->cur++) + f->lb; |
| 381 | break; |
| 382 | case SEMI: |
| 383 | CHECK_BOUND(bs, 2); |
| 384 | len = get_len(bs); |
| 385 | break; |
| 386 | default: |
| 387 | len = 0; |
| 388 | break; |
| 389 | } |
| 390 | |
| 391 | bs->cur += len >> 3; |
| 392 | bs->bit = len & 7; |
| 393 | |
| 394 | CHECK_BOUND(bs, 0); |
| 395 | return H323_ERROR_NONE; |
| 396 | } |
| 397 | |
| 398 | /****************************************************************************/ |
Jan Engelhardt | 905e3e8 | 2008-01-31 04:50:05 -0800 | [diff] [blame] | 399 | static int decode_numstr(bitstr_t *bs, const struct field_t *f, |
| 400 | char *base, int level) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 401 | { |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 402 | unsigned int len; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 403 | |
| 404 | PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name); |
| 405 | |
| 406 | /* 2 <= Range <= 255 */ |
| 407 | len = get_bits(bs, f->sz) + f->lb; |
| 408 | |
| 409 | BYTE_ALIGN(bs); |
| 410 | INC_BITS(bs, (len << 2)); |
| 411 | |
| 412 | CHECK_BOUND(bs, 0); |
| 413 | return H323_ERROR_NONE; |
| 414 | } |
| 415 | |
| 416 | /****************************************************************************/ |
Jan Engelhardt | 905e3e8 | 2008-01-31 04:50:05 -0800 | [diff] [blame] | 417 | static int decode_octstr(bitstr_t *bs, const struct field_t *f, |
| 418 | char *base, int level) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 419 | { |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 420 | unsigned int len; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 421 | |
| 422 | PRINT("%*.s%s", level * TAB_SIZE, " ", f->name); |
| 423 | |
| 424 | switch (f->sz) { |
| 425 | case FIXD: /* Range == 1 */ |
| 426 | if (f->lb > 2) { |
| 427 | BYTE_ALIGN(bs); |
| 428 | if (base && (f->attr & DECODE)) { |
| 429 | /* The IP Address */ |
| 430 | IFTHEN(f->lb == 4, |
| 431 | PRINT(" = %d.%d.%d.%d:%d", |
| 432 | bs->cur[0], bs->cur[1], |
| 433 | bs->cur[2], bs->cur[3], |
| 434 | bs->cur[4] * 256 + bs->cur[5])); |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 435 | *((unsigned int *)(base + f->offset)) = |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 436 | bs->cur - bs->buf; |
| 437 | } |
| 438 | } |
| 439 | len = f->lb; |
| 440 | break; |
| 441 | case BYTE: /* Range == 256 */ |
| 442 | BYTE_ALIGN(bs); |
| 443 | CHECK_BOUND(bs, 1); |
| 444 | len = (*bs->cur++) + f->lb; |
| 445 | break; |
| 446 | case SEMI: |
| 447 | BYTE_ALIGN(bs); |
| 448 | CHECK_BOUND(bs, 2); |
| 449 | len = get_len(bs) + f->lb; |
| 450 | break; |
| 451 | default: /* 2 <= Range <= 255 */ |
| 452 | len = get_bits(bs, f->sz) + f->lb; |
| 453 | BYTE_ALIGN(bs); |
| 454 | break; |
| 455 | } |
| 456 | |
| 457 | bs->cur += len; |
| 458 | |
| 459 | PRINT("\n"); |
| 460 | |
| 461 | CHECK_BOUND(bs, 0); |
| 462 | return H323_ERROR_NONE; |
| 463 | } |
| 464 | |
| 465 | /****************************************************************************/ |
Jan Engelhardt | 905e3e8 | 2008-01-31 04:50:05 -0800 | [diff] [blame] | 466 | static int decode_bmpstr(bitstr_t *bs, const struct field_t *f, |
| 467 | char *base, int level) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 468 | { |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 469 | unsigned int len; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 470 | |
| 471 | PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name); |
| 472 | |
| 473 | switch (f->sz) { |
| 474 | case BYTE: /* Range == 256 */ |
| 475 | BYTE_ALIGN(bs); |
| 476 | CHECK_BOUND(bs, 1); |
| 477 | len = (*bs->cur++) + f->lb; |
| 478 | break; |
| 479 | default: /* 2 <= Range <= 255 */ |
| 480 | len = get_bits(bs, f->sz) + f->lb; |
| 481 | BYTE_ALIGN(bs); |
| 482 | break; |
| 483 | } |
| 484 | |
| 485 | bs->cur += len << 1; |
| 486 | |
| 487 | CHECK_BOUND(bs, 0); |
| 488 | return H323_ERROR_NONE; |
| 489 | } |
| 490 | |
| 491 | /****************************************************************************/ |
Jan Engelhardt | 905e3e8 | 2008-01-31 04:50:05 -0800 | [diff] [blame] | 492 | static int decode_seq(bitstr_t *bs, const struct field_t *f, |
| 493 | char *base, int level) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 494 | { |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 495 | unsigned int ext, bmp, i, opt, len = 0, bmp2, bmp2_len; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 496 | int err; |
Jan Engelhardt | 905e3e8 | 2008-01-31 04:50:05 -0800 | [diff] [blame] | 497 | const struct field_t *son; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 498 | unsigned char *beg = NULL; |
| 499 | |
| 500 | PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name); |
| 501 | |
| 502 | /* Decode? */ |
| 503 | base = (base && (f->attr & DECODE)) ? base + f->offset : NULL; |
| 504 | |
| 505 | /* Extensible? */ |
| 506 | ext = (f->attr & EXT) ? get_bit(bs) : 0; |
| 507 | |
| 508 | /* Get fields bitmap */ |
| 509 | bmp = get_bitmap(bs, f->sz); |
| 510 | if (base) |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 511 | *(unsigned int *)base = bmp; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 512 | |
| 513 | /* Decode the root components */ |
| 514 | for (i = opt = 0, son = f->fields; i < f->lb; i++, son++) { |
| 515 | if (son->attr & STOP) { |
| 516 | PRINT("%*.s%s\n", (level + 1) * TAB_SIZE, " ", |
| 517 | son->name); |
| 518 | return H323_ERROR_STOP; |
| 519 | } |
| 520 | |
| 521 | if (son->attr & OPT) { /* Optional component */ |
| 522 | if (!((0x80000000U >> (opt++)) & bmp)) /* Not exist */ |
| 523 | continue; |
| 524 | } |
| 525 | |
| 526 | /* Decode */ |
| 527 | if (son->attr & OPEN) { /* Open field */ |
| 528 | CHECK_BOUND(bs, 2); |
| 529 | len = get_len(bs); |
| 530 | CHECK_BOUND(bs, len); |
Jing Min Zhao | 25845b5 | 2007-07-05 17:05:01 -0700 | [diff] [blame] | 531 | if (!base || !(son->attr & DECODE)) { |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 532 | PRINT("%*.s%s\n", (level + 1) * TAB_SIZE, |
| 533 | " ", son->name); |
| 534 | bs->cur += len; |
| 535 | continue; |
| 536 | } |
| 537 | beg = bs->cur; |
| 538 | |
| 539 | /* Decode */ |
| 540 | if ((err = (Decoders[son->type]) (bs, son, base, |
Patrick McHardy | 7185989 | 2006-05-23 15:07:07 -0700 | [diff] [blame] | 541 | level + 1)) < |
| 542 | H323_ERROR_NONE) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 543 | return err; |
| 544 | |
| 545 | bs->cur = beg + len; |
| 546 | bs->bit = 0; |
| 547 | } else if ((err = (Decoders[son->type]) (bs, son, base, |
Patrick McHardy | 7185989 | 2006-05-23 15:07:07 -0700 | [diff] [blame] | 548 | level + 1)) < |
| 549 | H323_ERROR_NONE) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 550 | return err; |
| 551 | } |
| 552 | |
| 553 | /* No extension? */ |
| 554 | if (!ext) |
| 555 | return H323_ERROR_NONE; |
| 556 | |
| 557 | /* Get the extension bitmap */ |
| 558 | bmp2_len = get_bits(bs, 7) + 1; |
| 559 | CHECK_BOUND(bs, (bmp2_len + 7) >> 3); |
| 560 | bmp2 = get_bitmap(bs, bmp2_len); |
| 561 | bmp |= bmp2 >> f->sz; |
| 562 | if (base) |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 563 | *(unsigned int *)base = bmp; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 564 | BYTE_ALIGN(bs); |
| 565 | |
| 566 | /* Decode the extension components */ |
| 567 | for (opt = 0; opt < bmp2_len; opt++, i++, son++) { |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 568 | /* Check Range */ |
| 569 | if (i >= f->ub) { /* Newer Version? */ |
| 570 | CHECK_BOUND(bs, 2); |
| 571 | len = get_len(bs); |
| 572 | CHECK_BOUND(bs, len); |
| 573 | bs->cur += len; |
| 574 | continue; |
| 575 | } |
| 576 | |
Jing Min Zhao | 558585a | 2007-07-07 22:13:17 -0700 | [diff] [blame] | 577 | if (son->attr & STOP) { |
| 578 | PRINT("%*.s%s\n", (level + 1) * TAB_SIZE, " ", |
| 579 | son->name); |
| 580 | return H323_ERROR_STOP; |
| 581 | } |
| 582 | |
| 583 | if (!((0x80000000 >> opt) & bmp2)) /* Not present */ |
| 584 | continue; |
| 585 | |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 586 | CHECK_BOUND(bs, 2); |
| 587 | len = get_len(bs); |
| 588 | CHECK_BOUND(bs, len); |
| 589 | if (!base || !(son->attr & DECODE)) { |
| 590 | PRINT("%*.s%s\n", (level + 1) * TAB_SIZE, " ", |
| 591 | son->name); |
| 592 | bs->cur += len; |
| 593 | continue; |
| 594 | } |
| 595 | beg = bs->cur; |
| 596 | |
| 597 | if ((err = (Decoders[son->type]) (bs, son, base, |
Patrick McHardy | 7185989 | 2006-05-23 15:07:07 -0700 | [diff] [blame] | 598 | level + 1)) < |
| 599 | H323_ERROR_NONE) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 600 | return err; |
| 601 | |
| 602 | bs->cur = beg + len; |
| 603 | bs->bit = 0; |
| 604 | } |
| 605 | return H323_ERROR_NONE; |
| 606 | } |
| 607 | |
| 608 | /****************************************************************************/ |
Jan Engelhardt | 905e3e8 | 2008-01-31 04:50:05 -0800 | [diff] [blame] | 609 | static int decode_seqof(bitstr_t *bs, const struct field_t *f, |
| 610 | char *base, int level) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 611 | { |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 612 | unsigned int count, effective_count = 0, i, len = 0; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 613 | int err; |
Jan Engelhardt | 905e3e8 | 2008-01-31 04:50:05 -0800 | [diff] [blame] | 614 | const struct field_t *son; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 615 | unsigned char *beg = NULL; |
| 616 | |
| 617 | PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name); |
| 618 | |
| 619 | /* Decode? */ |
| 620 | base = (base && (f->attr & DECODE)) ? base + f->offset : NULL; |
| 621 | |
| 622 | /* Decode item count */ |
| 623 | switch (f->sz) { |
| 624 | case BYTE: |
| 625 | BYTE_ALIGN(bs); |
| 626 | CHECK_BOUND(bs, 1); |
| 627 | count = *bs->cur++; |
| 628 | break; |
| 629 | case WORD: |
| 630 | BYTE_ALIGN(bs); |
| 631 | CHECK_BOUND(bs, 2); |
| 632 | count = *bs->cur++; |
| 633 | count <<= 8; |
David Sterba | b4232a2 | 2011-04-04 15:21:02 +0200 | [diff] [blame] | 634 | count += *bs->cur++; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 635 | break; |
| 636 | case SEMI: |
| 637 | BYTE_ALIGN(bs); |
| 638 | CHECK_BOUND(bs, 2); |
| 639 | count = get_len(bs); |
| 640 | break; |
| 641 | default: |
| 642 | count = get_bits(bs, f->sz); |
| 643 | break; |
| 644 | } |
| 645 | count += f->lb; |
| 646 | |
| 647 | /* Write Count */ |
| 648 | if (base) { |
| 649 | effective_count = count > f->ub ? f->ub : count; |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 650 | *(unsigned int *)base = effective_count; |
| 651 | base += sizeof(unsigned int); |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 652 | } |
| 653 | |
| 654 | /* Decode nested field */ |
| 655 | son = f->fields; |
| 656 | if (base) |
| 657 | base -= son->offset; |
| 658 | for (i = 0; i < count; i++) { |
| 659 | if (son->attr & OPEN) { |
| 660 | BYTE_ALIGN(bs); |
| 661 | len = get_len(bs); |
| 662 | CHECK_BOUND(bs, len); |
| 663 | if (!base || !(son->attr & DECODE)) { |
| 664 | PRINT("%*.s%s\n", (level + 1) * TAB_SIZE, |
| 665 | " ", son->name); |
| 666 | bs->cur += len; |
| 667 | continue; |
| 668 | } |
| 669 | beg = bs->cur; |
| 670 | |
| 671 | if ((err = (Decoders[son->type]) (bs, son, |
| 672 | i < |
| 673 | effective_count ? |
| 674 | base : NULL, |
Patrick McHardy | 7185989 | 2006-05-23 15:07:07 -0700 | [diff] [blame] | 675 | level + 1)) < |
| 676 | H323_ERROR_NONE) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 677 | return err; |
| 678 | |
| 679 | bs->cur = beg + len; |
| 680 | bs->bit = 0; |
| 681 | } else |
Patrick McHardy | 7185989 | 2006-05-23 15:07:07 -0700 | [diff] [blame] | 682 | if ((err = (Decoders[son->type]) (bs, son, |
| 683 | i < |
| 684 | effective_count ? |
| 685 | base : NULL, |
| 686 | level + 1)) < |
| 687 | H323_ERROR_NONE) |
| 688 | return err; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 689 | |
| 690 | if (base) |
| 691 | base += son->offset; |
| 692 | } |
| 693 | |
| 694 | return H323_ERROR_NONE; |
| 695 | } |
| 696 | |
| 697 | |
| 698 | /****************************************************************************/ |
Jan Engelhardt | 905e3e8 | 2008-01-31 04:50:05 -0800 | [diff] [blame] | 699 | static int decode_choice(bitstr_t *bs, const struct field_t *f, |
| 700 | char *base, int level) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 701 | { |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 702 | unsigned int type, ext, len = 0; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 703 | int err; |
Jan Engelhardt | 905e3e8 | 2008-01-31 04:50:05 -0800 | [diff] [blame] | 704 | const struct field_t *son; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 705 | unsigned char *beg = NULL; |
| 706 | |
| 707 | PRINT("%*.s%s\n", level * TAB_SIZE, " ", f->name); |
| 708 | |
| 709 | /* Decode? */ |
| 710 | base = (base && (f->attr & DECODE)) ? base + f->offset : NULL; |
| 711 | |
| 712 | /* Decode the choice index number */ |
| 713 | if ((f->attr & EXT) && get_bit(bs)) { |
| 714 | ext = 1; |
| 715 | type = get_bits(bs, 7) + f->lb; |
| 716 | } else { |
| 717 | ext = 0; |
| 718 | type = get_bits(bs, f->sz); |
Jing Min Zhao | 25845b5 | 2007-07-05 17:05:01 -0700 | [diff] [blame] | 719 | if (type >= f->lb) |
| 720 | return H323_ERROR_RANGE; |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 721 | } |
| 722 | |
Patrick McHardy | 4228e2a | 2006-05-03 23:17:11 -0700 | [diff] [blame] | 723 | /* Write Type */ |
| 724 | if (base) |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 725 | *(unsigned int *)base = type; |
Patrick McHardy | 4228e2a | 2006-05-03 23:17:11 -0700 | [diff] [blame] | 726 | |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 727 | /* Check Range */ |
| 728 | if (type >= f->ub) { /* Newer version? */ |
| 729 | BYTE_ALIGN(bs); |
| 730 | len = get_len(bs); |
| 731 | CHECK_BOUND(bs, len); |
| 732 | bs->cur += len; |
| 733 | return H323_ERROR_NONE; |
| 734 | } |
| 735 | |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 736 | /* Transfer to son level */ |
| 737 | son = &f->fields[type]; |
| 738 | if (son->attr & STOP) { |
| 739 | PRINT("%*.s%s\n", (level + 1) * TAB_SIZE, " ", son->name); |
| 740 | return H323_ERROR_STOP; |
| 741 | } |
| 742 | |
| 743 | if (ext || (son->attr & OPEN)) { |
| 744 | BYTE_ALIGN(bs); |
| 745 | len = get_len(bs); |
| 746 | CHECK_BOUND(bs, len); |
| 747 | if (!base || !(son->attr & DECODE)) { |
| 748 | PRINT("%*.s%s\n", (level + 1) * TAB_SIZE, " ", |
| 749 | son->name); |
| 750 | bs->cur += len; |
| 751 | return H323_ERROR_NONE; |
| 752 | } |
| 753 | beg = bs->cur; |
| 754 | |
Patrick McHardy | 7185989 | 2006-05-23 15:07:07 -0700 | [diff] [blame] | 755 | if ((err = (Decoders[son->type]) (bs, son, base, level + 1)) < |
| 756 | H323_ERROR_NONE) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 757 | return err; |
| 758 | |
| 759 | bs->cur = beg + len; |
| 760 | bs->bit = 0; |
Patrick McHardy | 7185989 | 2006-05-23 15:07:07 -0700 | [diff] [blame] | 761 | } else if ((err = (Decoders[son->type]) (bs, son, base, level + 1)) < |
| 762 | H323_ERROR_NONE) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 763 | return err; |
| 764 | |
| 765 | return H323_ERROR_NONE; |
| 766 | } |
| 767 | |
| 768 | /****************************************************************************/ |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 769 | int DecodeRasMessage(unsigned char *buf, size_t sz, RasMessage *ras) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 770 | { |
Jan Engelhardt | 905e3e8 | 2008-01-31 04:50:05 -0800 | [diff] [blame] | 771 | static const struct field_t ras_message = { |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 772 | FNAME("RasMessage") CHOICE, 5, 24, 32, DECODE | EXT, |
| 773 | 0, _RasMessage |
| 774 | }; |
| 775 | bitstr_t bs; |
| 776 | |
| 777 | bs.buf = bs.beg = bs.cur = buf; |
| 778 | bs.end = buf + sz; |
| 779 | bs.bit = 0; |
| 780 | |
| 781 | return decode_choice(&bs, &ras_message, (char *) ras, 0); |
| 782 | } |
| 783 | |
| 784 | /****************************************************************************/ |
| 785 | static int DecodeH323_UserInformation(unsigned char *buf, unsigned char *beg, |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 786 | size_t sz, H323_UserInformation *uuie) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 787 | { |
Jan Engelhardt | 905e3e8 | 2008-01-31 04:50:05 -0800 | [diff] [blame] | 788 | static const struct field_t h323_userinformation = { |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 789 | FNAME("H323-UserInformation") SEQ, 1, 2, 2, DECODE | EXT, |
| 790 | 0, _H323_UserInformation |
| 791 | }; |
| 792 | bitstr_t bs; |
| 793 | |
| 794 | bs.buf = buf; |
| 795 | bs.beg = bs.cur = beg; |
| 796 | bs.end = beg + sz; |
| 797 | bs.bit = 0; |
| 798 | |
| 799 | return decode_seq(&bs, &h323_userinformation, (char *) uuie, 0); |
| 800 | } |
| 801 | |
| 802 | /****************************************************************************/ |
| 803 | int DecodeMultimediaSystemControlMessage(unsigned char *buf, size_t sz, |
| 804 | MultimediaSystemControlMessage * |
| 805 | mscm) |
| 806 | { |
Jan Engelhardt | 905e3e8 | 2008-01-31 04:50:05 -0800 | [diff] [blame] | 807 | static const struct field_t multimediasystemcontrolmessage = { |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 808 | FNAME("MultimediaSystemControlMessage") CHOICE, 2, 4, 4, |
| 809 | DECODE | EXT, 0, _MultimediaSystemControlMessage |
| 810 | }; |
| 811 | bitstr_t bs; |
| 812 | |
| 813 | bs.buf = bs.beg = bs.cur = buf; |
| 814 | bs.end = buf + sz; |
| 815 | bs.bit = 0; |
| 816 | |
| 817 | return decode_choice(&bs, &multimediasystemcontrolmessage, |
| 818 | (char *) mscm, 0); |
| 819 | } |
| 820 | |
| 821 | /****************************************************************************/ |
Jan Engelhardt | 1f807d6 | 2008-01-31 04:43:53 -0800 | [diff] [blame] | 822 | int DecodeQ931(unsigned char *buf, size_t sz, Q931 *q931) |
Jing Min Zhao | 5e35941d | 2006-03-20 23:41:17 -0800 | [diff] [blame] | 823 | { |
| 824 | unsigned char *p = buf; |
| 825 | int len; |
| 826 | |
| 827 | if (!p || sz < 1) |
| 828 | return H323_ERROR_BOUND; |
| 829 | |
| 830 | /* Protocol Discriminator */ |
| 831 | if (*p != 0x08) { |
| 832 | PRINT("Unknown Protocol Discriminator\n"); |
| 833 | return H323_ERROR_RANGE; |
| 834 | } |
| 835 | p++; |
| 836 | sz--; |
| 837 | |
| 838 | /* CallReferenceValue */ |
| 839 | if (sz < 1) |
| 840 | return H323_ERROR_BOUND; |
| 841 | len = *p++; |
| 842 | sz--; |
| 843 | if (sz < len) |
| 844 | return H323_ERROR_BOUND; |
| 845 | p += len; |
| 846 | sz -= len; |
| 847 | |
| 848 | /* Message Type */ |
| 849 | if (sz < 1) |
| 850 | return H323_ERROR_BOUND; |
| 851 | q931->MessageType = *p++; |
| 852 | PRINT("MessageType = %02X\n", q931->MessageType); |
| 853 | if (*p & 0x80) { |
| 854 | p++; |
| 855 | sz--; |
| 856 | } |
| 857 | |
| 858 | /* Decode Information Elements */ |
| 859 | while (sz > 0) { |
| 860 | if (*p == 0x7e) { /* UserUserIE */ |
| 861 | if (sz < 3) |
| 862 | break; |
| 863 | p++; |
| 864 | len = *p++ << 8; |
| 865 | len |= *p++; |
| 866 | sz -= 3; |
| 867 | if (sz < len) |
| 868 | break; |
| 869 | p++; |
| 870 | len--; |
| 871 | return DecodeH323_UserInformation(buf, p, len, |
| 872 | &q931->UUIE); |
| 873 | } |
| 874 | p++; |
| 875 | sz--; |
| 876 | if (sz < 1) |
| 877 | break; |
| 878 | len = *p++; |
| 879 | if (sz < len) |
| 880 | break; |
| 881 | p += len; |
| 882 | sz -= len; |
| 883 | } |
| 884 | |
| 885 | PRINT("Q.931 UUIE not found\n"); |
| 886 | |
| 887 | return H323_ERROR_BOUND; |
| 888 | } |