Harald Welte | 468b643 | 2014-09-11 13:05:51 +0800 | [diff] [blame] | 1 | /* (C) 2008-2010 by Harald Welte <laforge@gnumonks.org> |
| 2 | * |
| 3 | * All Rights Reserved |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License as published by |
| 7 | * the Free Software Foundation; either version 2 of the License, or |
| 8 | * (at your option) any later version. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License |
| 16 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 17 | * |
| 18 | */ |
| 19 | |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 20 | #include <stdio.h> |
| 21 | #include <stdint.h> |
Max | dbd3a92 | 2017-01-02 14:10:30 +0100 | [diff] [blame] | 22 | #include <errno.h> |
Pablo Neira Ayuso | 8341934 | 2011-03-22 16:36:13 +0100 | [diff] [blame] | 23 | #include <osmocom/core/utils.h> |
| 24 | #include <osmocom/gsm/tlv.h> |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 25 | |
Harald Welte | 57c7d37 | 2011-08-17 17:50:55 +0200 | [diff] [blame] | 26 | /*! \addtogroup tlv |
| 27 | * @{ |
Harald Welte | 96e2a00 | 2017-06-12 21:44:18 +0200 | [diff] [blame] | 28 | * \brief Osmocom TLV Parser |
| 29 | * |
| 30 | * The Osmocom TLV parser is intended to operate as a low-level C |
| 31 | * implementation without dynamic memory allocations. Basically, it |
| 32 | * iterates over the IE (Information Elements) of the message and fills |
| 33 | * an array of pointers, indexed by the IEI (IE Identifier). The |
| 34 | * parser output is thus an array of pointers to the start of the |
| 35 | * respective IE inside the message. |
| 36 | * |
| 37 | * The TLV parser is configured by a TLV parser definition, which |
| 38 | * determines which if the IEIs for a given protocol are of which |
| 39 | * particular type. Types are e.g. TV (Tag + single byte value), Tag + |
| 40 | * fixed-length value, TLV with 8bit length, TLV with 16bit length, TLV |
| 41 | * with variable-length length field, etc. |
Harald Welte | 57c7d37 | 2011-08-17 17:50:55 +0200 | [diff] [blame] | 42 | */ |
Harald Welte | 96e2a00 | 2017-06-12 21:44:18 +0200 | [diff] [blame] | 43 | |
Katerina Barone-Adesi | c28c6a0 | 2013-02-15 13:27:59 +0100 | [diff] [blame] | 44 | /*! \file tlv_parser.c */ |
Harald Welte | 57c7d37 | 2011-08-17 17:50:55 +0200 | [diff] [blame] | 45 | |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 46 | struct tlv_definition tvlv_att_def; |
Harald Welte | 2fe6847 | 2012-07-14 01:50:33 +0200 | [diff] [blame] | 47 | struct tlv_definition vtvlv_gan_att_def; |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 48 | |
Harald Welte | 57c7d37 | 2011-08-17 17:50:55 +0200 | [diff] [blame] | 49 | /*! \brief Dump pasred TLV structure to stdout */ |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 50 | int tlv_dump(struct tlv_parsed *dec) |
| 51 | { |
| 52 | int i; |
| 53 | |
| 54 | for (i = 0; i <= 0xff; i++) { |
| 55 | if (!dec->lv[i].val) |
| 56 | continue; |
| 57 | printf("T=%02x L=%d\n", i, dec->lv[i].len); |
| 58 | } |
| 59 | return 0; |
| 60 | } |
| 61 | |
Max | dbd3a92 | 2017-01-02 14:10:30 +0100 | [diff] [blame] | 62 | /*! \brief Copy \ref tlv_parsed using given talloc context |
| 63 | * \param[in] tp_orig Parsed TLV structure |
| 64 | * \param[in] ctx Talloc context for allocations |
| 65 | * \returns NULL on errors, \ref tlv_parsed pointer otherwise |
| 66 | */ |
| 67 | struct tlv_parsed *osmo_tlvp_copy(const struct tlv_parsed *tp_orig, void *ctx) |
| 68 | { |
| 69 | struct tlv_parsed *tp_out; |
| 70 | size_t i, len; |
| 71 | |
| 72 | tp_out = talloc_zero(ctx, struct tlv_parsed); |
| 73 | if (!tp_out) |
| 74 | return NULL; |
| 75 | |
| 76 | /* if the original is NULL, return empty tlvp */ |
| 77 | if (!tp_orig) |
| 78 | return tp_out; |
| 79 | |
| 80 | for (i = 0; i < ARRAY_SIZE(tp_orig->lv); i++) { |
| 81 | len = tp_orig->lv[i].len; |
| 82 | tp_out->lv[i].len = len; |
| 83 | if (len && tp_out->lv[i].val) { |
| 84 | tp_out->lv[i].val = talloc_zero_size(tp_out, len); |
| 85 | if (!tp_out->lv[i].val) { |
| 86 | talloc_free(tp_out); |
| 87 | return NULL; |
| 88 | } |
| 89 | memcpy((uint8_t *)tp_out->lv[i].val, tp_orig->lv[i].val, |
| 90 | len); |
| 91 | } |
| 92 | } |
| 93 | |
| 94 | return tp_out; |
| 95 | } |
| 96 | |
| 97 | /*! \brief Merge all \ref tlv_parsed attributes of 'src' into 'dst' |
| 98 | * \param[in] dst Parsed TLV structure to merge into |
| 99 | * \param[in] src Parsed TLV structure to merge from |
| 100 | * \returns 0 on success, negative on error |
| 101 | */ |
| 102 | int osmo_tlvp_merge(struct tlv_parsed *dst, const struct tlv_parsed *src) |
| 103 | { |
| 104 | size_t i, len; |
| 105 | for (i = 0; i < ARRAY_SIZE(dst->lv); i++) { |
| 106 | len = src->lv[i].len; |
| 107 | if (len == 0 || src->lv[i].val == NULL) |
| 108 | continue; |
| 109 | if (dst->lv[i].val) { |
| 110 | talloc_free((uint8_t *) dst->lv[i].val); |
| 111 | dst->lv[i].len = 0; |
| 112 | } |
| 113 | dst->lv[i].val = talloc_zero_size(dst, len); |
| 114 | if (!dst->lv[i].val) |
| 115 | return -ENOMEM; |
| 116 | memcpy((uint8_t *) dst->lv[i].val, src->lv[i].val, len); |
| 117 | } |
| 118 | return 0; |
| 119 | } |
| 120 | |
Harald Welte | 57c7d37 | 2011-08-17 17:50:55 +0200 | [diff] [blame] | 121 | /*! \brief Parse a single TLV encoded IE |
| 122 | * \param[out] o_tag the tag of the IE that was found |
| 123 | * \param[out] o_len length of the IE that was found |
| 124 | * \param[out] o_val pointer to the data of the IE that was found |
| 125 | * \param[in] def structure defining the valid TLV tags / configurations |
| 126 | * \param[in] buf the input data buffer to be parsed |
| 127 | * \param[in] buf_len length of the input data buffer |
| 128 | * \returns number of bytes consumed by the TLV entry / IE parsed |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 129 | */ |
| 130 | int tlv_parse_one(uint8_t *o_tag, uint16_t *o_len, const uint8_t **o_val, |
| 131 | const struct tlv_definition *def, |
| 132 | const uint8_t *buf, int buf_len) |
| 133 | { |
| 134 | uint8_t tag; |
| 135 | int len; |
| 136 | |
| 137 | tag = *buf; |
| 138 | *o_tag = tag; |
| 139 | |
Andreas Eversberg | cd2a74b | 2010-07-12 08:55:14 +0200 | [diff] [blame] | 140 | /* single octet TV IE */ |
| 141 | if (def->def[tag & 0xf0].type == TLV_TYPE_SINGLE_TV) { |
| 142 | *o_tag = tag & 0xf0; |
| 143 | *o_val = buf; |
| 144 | *o_len = 1; |
| 145 | return 1; |
| 146 | } |
| 147 | |
Neels Hofmeyr | 667e83d | 2015-11-02 20:18:11 +0100 | [diff] [blame] | 148 | /* FIXME: use tables for known IEI */ |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 149 | switch (def->def[tag].type) { |
| 150 | case TLV_TYPE_T: |
| 151 | /* GSM TS 04.07 11.2.4: Type 1 TV or Type 2 T */ |
| 152 | *o_val = buf; |
| 153 | *o_len = 0; |
| 154 | len = 1; |
| 155 | break; |
| 156 | case TLV_TYPE_TV: |
| 157 | *o_val = buf+1; |
| 158 | *o_len = 1; |
| 159 | len = 2; |
| 160 | break; |
| 161 | case TLV_TYPE_FIXED: |
| 162 | *o_val = buf+1; |
| 163 | *o_len = def->def[tag].fixed_len; |
| 164 | len = def->def[tag].fixed_len + 1; |
| 165 | break; |
| 166 | case TLV_TYPE_TLV: |
Harald Welte | 2fe6847 | 2012-07-14 01:50:33 +0200 | [diff] [blame] | 167 | tlv: /* GSM TS 04.07 11.2.4: Type 4 TLV */ |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 168 | if (buf + 1 > buf + buf_len) |
| 169 | return -1; |
| 170 | *o_val = buf+2; |
| 171 | *o_len = *(buf+1); |
| 172 | len = *o_len + 2; |
| 173 | if (len > buf_len) |
| 174 | return -2; |
| 175 | break; |
Harald Welte | 2fe6847 | 2012-07-14 01:50:33 +0200 | [diff] [blame] | 176 | case TLV_TYPE_vTvLV_GAN: /* 44.318 / 11.1.4 */ |
| 177 | /* FIXME: variable-length TAG! */ |
| 178 | if (*(buf+1) & 0x80) { |
| 179 | /* like TL16Vbut without highest bit of len */ |
| 180 | if (2 > buf_len) |
| 181 | return -1; |
| 182 | *o_val = buf+3; |
| 183 | *o_len = (*(buf+1) & 0x7F) << 8 | *(buf+2); |
| 184 | len = *o_len + 3; |
| 185 | if (len > buf_len) |
| 186 | return -2; |
| 187 | } else { |
| 188 | /* like TLV */ |
| 189 | goto tlv; |
| 190 | } |
| 191 | break; |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 192 | case TLV_TYPE_TvLV: |
| 193 | if (*(buf+1) & 0x80) { |
| 194 | /* like TLV, but without highest bit of len */ |
| 195 | if (buf + 1 > buf + buf_len) |
| 196 | return -1; |
| 197 | *o_val = buf+2; |
| 198 | *o_len = *(buf+1) & 0x7f; |
| 199 | len = *o_len + 2; |
| 200 | if (len > buf_len) |
| 201 | return -2; |
| 202 | break; |
| 203 | } |
| 204 | /* like TL16V, fallthrough */ |
| 205 | case TLV_TYPE_TL16V: |
| 206 | if (2 > buf_len) |
| 207 | return -1; |
| 208 | *o_val = buf+3; |
| 209 | *o_len = *(buf+1) << 8 | *(buf+2); |
| 210 | len = *o_len + 3; |
| 211 | if (len > buf_len) |
| 212 | return -2; |
| 213 | break; |
| 214 | default: |
| 215 | return -3; |
| 216 | } |
| 217 | |
| 218 | return len; |
| 219 | } |
| 220 | |
Neels Hofmeyr | 667e83d | 2015-11-02 20:18:11 +0100 | [diff] [blame] | 221 | /*! \brief Parse an entire buffer of TLV encoded Information Elements |
Harald Welte | 57c7d37 | 2011-08-17 17:50:55 +0200 | [diff] [blame] | 222 | * \param[out] dec caller-allocated pointer to \ref tlv_parsed |
| 223 | * \param[in] def structure defining the valid TLV tags / configurations |
| 224 | * \param[in] buf the input data buffer to be parsed |
| 225 | * \param[in] buf_len length of the input data buffer |
| 226 | * \param[in] lv_tag an initial LV tag at the start of the buffer |
| 227 | * \param[in] lv_tag2 a second initial LV tag following the \a lv_tag |
| 228 | * \returns number of bytes consumed by the TLV entry / IE parsed |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 229 | */ |
| 230 | int tlv_parse(struct tlv_parsed *dec, const struct tlv_definition *def, |
| 231 | const uint8_t *buf, int buf_len, uint8_t lv_tag, |
| 232 | uint8_t lv_tag2) |
| 233 | { |
| 234 | int ofs = 0, num_parsed = 0; |
| 235 | uint16_t len; |
| 236 | |
| 237 | memset(dec, 0, sizeof(*dec)); |
| 238 | |
| 239 | if (lv_tag) { |
| 240 | if (ofs > buf_len) |
| 241 | return -1; |
| 242 | dec->lv[lv_tag].val = &buf[ofs+1]; |
| 243 | dec->lv[lv_tag].len = buf[ofs]; |
| 244 | len = dec->lv[lv_tag].len + 1; |
| 245 | if (ofs + len > buf_len) |
| 246 | return -2; |
| 247 | num_parsed++; |
| 248 | ofs += len; |
| 249 | } |
| 250 | if (lv_tag2) { |
| 251 | if (ofs > buf_len) |
| 252 | return -1; |
| 253 | dec->lv[lv_tag2].val = &buf[ofs+1]; |
| 254 | dec->lv[lv_tag2].len = buf[ofs]; |
| 255 | len = dec->lv[lv_tag2].len + 1; |
| 256 | if (ofs + len > buf_len) |
| 257 | return -2; |
| 258 | num_parsed++; |
| 259 | ofs += len; |
| 260 | } |
| 261 | |
| 262 | while (ofs < buf_len) { |
| 263 | int rv; |
| 264 | uint8_t tag; |
| 265 | const uint8_t *val; |
| 266 | |
| 267 | rv = tlv_parse_one(&tag, &len, &val, def, |
| 268 | &buf[ofs], buf_len-ofs); |
| 269 | if (rv < 0) |
| 270 | return rv; |
| 271 | dec->lv[tag].val = val; |
| 272 | dec->lv[tag].len = len; |
| 273 | ofs += rv; |
| 274 | num_parsed++; |
| 275 | } |
| 276 | //tlv_dump(dec); |
| 277 | return num_parsed; |
| 278 | } |
| 279 | |
Harald Welte | 96e2a00 | 2017-06-12 21:44:18 +0200 | [diff] [blame] | 280 | /*! \brief take a master (src) tlvdev and fill up all empty slots in 'dst' |
| 281 | * \param dst TLV parser definition that is to be patched |
| 282 | * \param[in] src TLV parser definition whose content is patched into \a dst */ |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 283 | void tlv_def_patch(struct tlv_definition *dst, const struct tlv_definition *src) |
| 284 | { |
| 285 | int i; |
| 286 | |
| 287 | for (i = 0; i < ARRAY_SIZE(dst->def); i++) { |
| 288 | if (src->def[i].type == TLV_TYPE_NONE) |
| 289 | continue; |
| 290 | if (dst->def[i].type == TLV_TYPE_NONE) |
| 291 | dst->def[i] = src->def[i]; |
| 292 | } |
| 293 | } |
| 294 | |
| 295 | static __attribute__((constructor)) void on_dso_load_tlv(void) |
| 296 | { |
| 297 | int i; |
| 298 | for (i = 0; i < ARRAY_SIZE(tvlv_att_def.def); i++) |
| 299 | tvlv_att_def.def[i].type = TLV_TYPE_TvLV; |
Harald Welte | 2fe6847 | 2012-07-14 01:50:33 +0200 | [diff] [blame] | 300 | |
| 301 | for (i = 0; i < ARRAY_SIZE(vtvlv_gan_att_def.def); i++) |
| 302 | vtvlv_gan_att_def.def[i].type = TLV_TYPE_vTvLV_GAN; |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 303 | } |
Harald Welte | 57c7d37 | 2011-08-17 17:50:55 +0200 | [diff] [blame] | 304 | |
Harald Welte | fbd02fa | 2016-04-25 15:19:35 +0200 | [diff] [blame] | 305 | /*! Advance the data pointer, subtract length and assign value pointer |
| 306 | * \param data pointer to the pointer to data |
| 307 | * \param data_len pointer to size_t containing \arg data length |
| 308 | * \param[in] len the length that we expect the fixed IE to hav |
| 309 | * \param[out] value pointer to pointer of value part of IE |
| 310 | * \returns length of IE value; negative in case of error |
| 311 | */ |
| 312 | int osmo_shift_v_fixed(uint8_t **data, size_t *data_len, |
| 313 | size_t len, uint8_t **value) |
| 314 | { |
| 315 | if (len > *data_len) |
| 316 | goto fail; |
| 317 | |
| 318 | if (value) |
| 319 | *value = *data; |
| 320 | |
| 321 | *data += len; |
| 322 | *data_len -= len; |
| 323 | |
| 324 | return len; |
| 325 | |
| 326 | fail: |
| 327 | *data += *data_len; |
| 328 | *data_len = 0; |
| 329 | return -1; |
| 330 | } |
| 331 | |
| 332 | /*! Match tag, check length and assign value pointer |
| 333 | * \param data pointer to the pointer to data |
| 334 | * \param data_len pointer to size_t containing \arg data length |
| 335 | * \param[in] tag the tag (IEI) that we expect at \arg data |
| 336 | * \param[in] len the length that we expect the fixed IE to have |
| 337 | * \param[out] value pointer to pointer of value part of IE |
| 338 | * \returns length of IE value; negative in case of error |
| 339 | */ |
| 340 | int osmo_match_shift_tv_fixed(uint8_t **data, size_t *data_len, |
| 341 | uint8_t tag, size_t len, |
| 342 | uint8_t **value) |
| 343 | { |
| 344 | size_t ie_len; |
| 345 | |
| 346 | if (*data_len == 0) |
| 347 | goto fail; |
| 348 | |
| 349 | if ((*data)[0] != tag) |
| 350 | return 0; |
| 351 | |
| 352 | if (len > *data_len - 1) |
| 353 | goto fail; |
| 354 | |
| 355 | if (value) |
| 356 | *value = *data + 1; |
| 357 | |
| 358 | ie_len = len + 1; |
| 359 | *data += ie_len; |
| 360 | *data_len -= ie_len; |
| 361 | |
| 362 | return ie_len; |
| 363 | |
| 364 | fail: |
| 365 | *data += *data_len; |
| 366 | *data_len = 0; |
| 367 | return -1; |
| 368 | } |
| 369 | |
| 370 | /*! Verify TLV header and advance data / subtract length |
| 371 | * \param data pointer to the pointer to data |
| 372 | * \param data_len pointer to size_t containing \arg data length |
| 373 | * \param[in] expected_tag the tag (IEI) that we expect at \arg data |
| 374 | * \param[out] value pointer to pointer of value part of IE |
| 375 | * \param[out] value_len pointer to length of \arg value |
| 376 | * \returns length of IE value; negative in case of error |
| 377 | */ |
| 378 | int osmo_match_shift_tlv(uint8_t **data, size_t *data_len, |
| 379 | uint8_t expected_tag, uint8_t **value, |
| 380 | size_t *value_len) |
| 381 | { |
| 382 | int rc; |
| 383 | uint8_t tag; |
| 384 | uint8_t *old_data = *data; |
| 385 | size_t old_data_len = *data_len; |
| 386 | |
| 387 | rc = osmo_shift_tlv(data, data_len, &tag, value, value_len); |
| 388 | |
| 389 | if (rc > 0 && tag != expected_tag) { |
| 390 | *data = old_data; |
| 391 | *data_len = old_data_len; |
| 392 | return 0; |
| 393 | } |
| 394 | |
| 395 | return rc; |
| 396 | } |
| 397 | |
| 398 | /*! Extract TLV and advance data pointer + subtract length |
| 399 | * \param data pointer to the pointer to data |
| 400 | * \param data_len pointer to size_t containing \arg data lengt |
| 401 | * \param[out] tag extract the tag (IEI) at start of \arg data |
| 402 | * \param[out] value extracted pointer to value part of TLV |
| 403 | * \param[out] value_len extracted length of \arg value |
| 404 | * \returns number of bytes subtracted |
| 405 | */ |
| 406 | int osmo_shift_tlv(uint8_t **data, size_t *data_len, |
| 407 | uint8_t *tag, uint8_t **value, size_t *value_len) |
| 408 | { |
| 409 | size_t len; |
| 410 | size_t ie_len; |
| 411 | |
| 412 | if (*data_len < 2) |
| 413 | goto fail; |
| 414 | |
| 415 | len = (*data)[1]; |
| 416 | if (len > *data_len - 2) |
| 417 | goto fail; |
| 418 | |
| 419 | if (tag) |
| 420 | *tag = (*data)[0]; |
| 421 | if (value) |
| 422 | *value = *data + 2; |
| 423 | if (value_len) |
| 424 | *value_len = len; |
| 425 | |
| 426 | ie_len = len + 2; |
| 427 | |
| 428 | *data += ie_len; |
| 429 | *data_len -= ie_len; |
| 430 | |
| 431 | return ie_len; |
| 432 | |
| 433 | fail: |
| 434 | *data += *data_len; |
| 435 | *data_len = 0; |
| 436 | return -1; |
| 437 | } |
| 438 | |
| 439 | /*! Extract LV and advance data pointer + subtract length |
| 440 | * \param data pointer to the pointer to data |
| 441 | * \param data_len pointer to size_t containing \arg data lengt |
| 442 | * \param[out] value extracted pointer to value part of TLV |
| 443 | * \param[out] value_len extracted length of \arg value |
| 444 | * \returns number of bytes subtracted |
| 445 | */ |
| 446 | int osmo_shift_lv(uint8_t **data, size_t *data_len, |
| 447 | uint8_t **value, size_t *value_len) |
| 448 | { |
| 449 | size_t len; |
| 450 | size_t ie_len; |
| 451 | |
| 452 | if (*data_len < 1) |
| 453 | goto fail; |
| 454 | |
| 455 | len = (*data)[0]; |
| 456 | if (len > *data_len - 1) |
| 457 | goto fail; |
| 458 | |
| 459 | if (value) |
| 460 | *value = *data + 1; |
| 461 | if (value_len) |
| 462 | *value_len = len; |
| 463 | |
| 464 | ie_len = len + 1; |
| 465 | *data += ie_len; |
| 466 | *data_len -= ie_len; |
| 467 | |
| 468 | return ie_len; |
| 469 | |
| 470 | fail: |
| 471 | *data += *data_len; |
| 472 | *data_len = 0; |
| 473 | return -1; |
| 474 | } |
| 475 | |
Sylvain Munaut | dca7d2c | 2012-04-18 21:53:23 +0200 | [diff] [blame] | 476 | /*! @} */ |