Holger Hans Peter Freyther | 8ac3a72 | 2014-08-04 11:52:52 +0200 | [diff] [blame] | 1 | /* GPRS utility functions */ |
| 2 | |
| 3 | /* (C) 2010 by Harald Welte <laforge@gnumonks.org> |
| 4 | * (C) 2010-2014 by On-Waves |
| 5 | * (C) 2013 by Holger Hans Peter Freyther |
| 6 | * All Rights Reserved |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU Affero General Public License as published by |
| 10 | * the Free Software Foundation; either version 3 of the License, or |
| 11 | * (at your option) any later version. |
| 12 | * |
| 13 | * This program is distributed in the hope that it will be useful, |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | * GNU Affero General Public License for more details. |
| 17 | * |
| 18 | * You should have received a copy of the GNU Affero General Public License |
| 19 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 20 | * |
| 21 | */ |
| 22 | #include <openbsc/gprs_utils.h> |
Jacob Erlbeck | c9a7ba3 | 2015-01-19 08:27:34 +0100 | [diff] [blame] | 23 | #include <openbsc/gsm_04_08_gprs.h> |
Holger Hans Peter Freyther | 8ac3a72 | 2014-08-04 11:52:52 +0200 | [diff] [blame] | 24 | |
| 25 | #include <osmocom/core/msgb.h> |
| 26 | #include <osmocom/gprs/gprs_ns.h> |
| 27 | |
Jacob Erlbeck | cf11e93 | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 28 | #include <osmocom/gsm/protocol/gsm_04_08.h> |
| 29 | |
Holger Hans Peter Freyther | 8ac3a72 | 2014-08-04 11:52:52 +0200 | [diff] [blame] | 30 | #include <string.h> |
| 31 | |
| 32 | /* FIXME: this needs to go to libosmocore/msgb.c */ |
| 33 | struct msgb *gprs_msgb_copy(const struct msgb *msg, const char *name) |
| 34 | { |
| 35 | struct libgb_msgb_cb *old_cb, *new_cb; |
| 36 | struct msgb *new_msg; |
| 37 | |
| 38 | new_msg = msgb_alloc(msg->data_len, name); |
| 39 | if (!new_msg) |
| 40 | return NULL; |
| 41 | |
| 42 | /* copy data */ |
| 43 | memcpy(new_msg->_data, msg->_data, new_msg->data_len); |
| 44 | |
| 45 | /* copy header */ |
| 46 | new_msg->len = msg->len; |
| 47 | new_msg->data += msg->data - msg->_data; |
| 48 | new_msg->head += msg->head - msg->_data; |
| 49 | new_msg->tail += msg->tail - msg->_data; |
| 50 | |
Jacob Erlbeck | 7557561 | 2014-09-22 18:50:08 +0200 | [diff] [blame] | 51 | if (msg->l1h) |
| 52 | new_msg->l1h = new_msg->_data + (msg->l1h - msg->_data); |
| 53 | if (msg->l2h) |
| 54 | new_msg->l2h = new_msg->_data + (msg->l2h - msg->_data); |
| 55 | if (msg->l3h) |
| 56 | new_msg->l3h = new_msg->_data + (msg->l3h - msg->_data); |
| 57 | if (msg->l4h) |
| 58 | new_msg->l4h = new_msg->_data + (msg->l4h - msg->_data); |
Holger Hans Peter Freyther | 8ac3a72 | 2014-08-04 11:52:52 +0200 | [diff] [blame] | 59 | |
| 60 | /* copy GB specific data */ |
| 61 | old_cb = LIBGB_MSGB_CB(msg); |
| 62 | new_cb = LIBGB_MSGB_CB(new_msg); |
| 63 | |
Jacob Erlbeck | 7557561 | 2014-09-22 18:50:08 +0200 | [diff] [blame] | 64 | if (old_cb->bssgph) |
| 65 | new_cb->bssgph = new_msg->_data + (old_cb->bssgph - msg->_data); |
| 66 | if (old_cb->llch) |
| 67 | new_cb->llch = new_msg->_data + (old_cb->llch - msg->_data); |
Holger Hans Peter Freyther | 8ac3a72 | 2014-08-04 11:52:52 +0200 | [diff] [blame] | 68 | |
| 69 | /* bssgp_cell_id is a pointer into the old msgb, so we need to make |
| 70 | * it a pointer into the new msgb */ |
Jacob Erlbeck | 7557561 | 2014-09-22 18:50:08 +0200 | [diff] [blame] | 71 | if (old_cb->bssgp_cell_id) |
| 72 | new_cb->bssgp_cell_id = new_msg->_data + |
| 73 | (old_cb->bssgp_cell_id - msg->_data); |
Holger Hans Peter Freyther | 8ac3a72 | 2014-08-04 11:52:52 +0200 | [diff] [blame] | 74 | new_cb->nsei = old_cb->nsei; |
| 75 | new_cb->bvci = old_cb->bvci; |
| 76 | new_cb->tlli = old_cb->tlli; |
| 77 | |
| 78 | return new_msg; |
| 79 | } |
| 80 | |
| 81 | /* TODO: Move this to libosmocore/msgb.c */ |
| 82 | int gprs_msgb_resize_area(struct msgb *msg, uint8_t *area, |
| 83 | size_t old_size, size_t new_size) |
| 84 | { |
| 85 | int rc; |
| 86 | uint8_t *rest = area + old_size; |
| 87 | int rest_len = msg->len - old_size - (area - msg->data); |
| 88 | int delta_size = (int)new_size - (int)old_size; |
| 89 | |
| 90 | if (delta_size == 0) |
| 91 | return 0; |
| 92 | |
| 93 | if (delta_size > 0) { |
| 94 | rc = msgb_trim(msg, msg->len + delta_size); |
| 95 | if (rc < 0) |
| 96 | return rc; |
| 97 | } |
| 98 | |
| 99 | memmove(area + new_size, area + old_size, rest_len); |
| 100 | |
| 101 | if (msg->l1h >= rest) |
| 102 | msg->l1h += delta_size; |
| 103 | if (msg->l2h >= rest) |
| 104 | msg->l2h += delta_size; |
| 105 | if (msg->l3h >= rest) |
| 106 | msg->l3h += delta_size; |
| 107 | if (msg->l4h >= rest) |
| 108 | msg->l4h += delta_size; |
| 109 | |
| 110 | if (delta_size < 0) |
| 111 | msgb_trim(msg, msg->len + delta_size); |
| 112 | |
| 113 | return 0; |
| 114 | } |
| 115 | |
| 116 | /* TODO: Move these conversion functions to a utils file. */ |
Holger Hans Peter Freyther | 2d10ad1 | 2014-08-04 14:22:13 +0200 | [diff] [blame] | 117 | /** |
| 118 | * out_str needs to have rest_chars amount of bytes or 1 whatever is bigger. |
| 119 | */ |
Holger Hans Peter Freyther | 8ac3a72 | 2014-08-04 11:52:52 +0200 | [diff] [blame] | 120 | char * gprs_apn_to_str(char *out_str, const uint8_t *apn_enc, size_t rest_chars) |
| 121 | { |
| 122 | char *str = out_str; |
| 123 | |
| 124 | while (rest_chars > 0 && apn_enc[0]) { |
| 125 | size_t label_size = apn_enc[0]; |
| 126 | if (label_size + 1 > rest_chars) |
| 127 | return NULL; |
| 128 | |
| 129 | memmove(str, apn_enc + 1, label_size); |
| 130 | str += label_size; |
| 131 | rest_chars -= label_size + 1; |
| 132 | apn_enc += label_size + 1; |
| 133 | |
| 134 | if (rest_chars) |
| 135 | *(str++) = '.'; |
| 136 | } |
| 137 | str[0] = '\0'; |
| 138 | |
| 139 | return out_str; |
| 140 | } |
| 141 | |
Holger Hans Peter Freyther | 2d10ad1 | 2014-08-04 14:22:13 +0200 | [diff] [blame] | 142 | int gprs_str_to_apn(uint8_t *apn_enc, size_t max_len, const char *str) |
Holger Hans Peter Freyther | 8ac3a72 | 2014-08-04 11:52:52 +0200 | [diff] [blame] | 143 | { |
Holger Hans Peter Freyther | 2d10ad1 | 2014-08-04 14:22:13 +0200 | [diff] [blame] | 144 | uint8_t *last_len_field; |
| 145 | int len; |
| 146 | |
| 147 | /* Can we even write the length field to the output? */ |
| 148 | if (max_len == 0) |
| 149 | return -1; |
| 150 | |
| 151 | /* Remember where we need to put the length once we know it */ |
| 152 | last_len_field = apn_enc; |
| 153 | len = 1; |
Holger Hans Peter Freyther | 8ac3a72 | 2014-08-04 11:52:52 +0200 | [diff] [blame] | 154 | apn_enc += 1; |
| 155 | |
| 156 | while (str[0]) { |
Holger Hans Peter Freyther | 2d10ad1 | 2014-08-04 14:22:13 +0200 | [diff] [blame] | 157 | if (len >= max_len) |
| 158 | return -1; |
| 159 | |
Holger Hans Peter Freyther | 8ac3a72 | 2014-08-04 11:52:52 +0200 | [diff] [blame] | 160 | if (str[0] == '.') { |
| 161 | *last_len_field = (apn_enc - last_len_field) - 1; |
| 162 | last_len_field = apn_enc; |
| 163 | } else { |
| 164 | *apn_enc = str[0]; |
| 165 | } |
| 166 | apn_enc += 1; |
| 167 | str += 1; |
| 168 | len += 1; |
Holger Hans Peter Freyther | 8ac3a72 | 2014-08-04 11:52:52 +0200 | [diff] [blame] | 169 | } |
| 170 | |
| 171 | *last_len_field = (apn_enc - last_len_field) - 1; |
| 172 | |
| 173 | return len; |
| 174 | } |
| 175 | |
Jacob Erlbeck | c9a7ba3 | 2015-01-19 08:27:34 +0100 | [diff] [blame] | 176 | /* GSM 04.08, 10.5.7.3 GPRS Timer */ |
| 177 | int gprs_tmr_to_secs(uint8_t tmr) |
| 178 | { |
| 179 | switch (tmr & GPRS_TMR_UNIT_MASK) { |
| 180 | case GPRS_TMR_2SECONDS: |
| 181 | return 2 * (tmr & GPRS_TMR_FACT_MASK); |
| 182 | default: |
| 183 | case GPRS_TMR_MINUTE: |
| 184 | return 60 * (tmr & GPRS_TMR_FACT_MASK); |
| 185 | case GPRS_TMR_6MINUTE: |
| 186 | return 360 * (tmr & GPRS_TMR_FACT_MASK); |
| 187 | case GPRS_TMR_DEACTIVATED: |
| 188 | return -1; |
| 189 | } |
| 190 | } |
| 191 | |
| 192 | /* This functions returns a tmr value such that |
| 193 | * - f is monotonic |
| 194 | * - f(s) <= s |
| 195 | * - f(s) == s if a tmr exists with s = gprs_tmr_to_secs(tmr) |
| 196 | * - the best possible resolution is used |
| 197 | * where |
| 198 | * f(s) = gprs_tmr_to_secs(gprs_secs_to_tmr_floor(s)) |
| 199 | */ |
| 200 | uint8_t gprs_secs_to_tmr_floor(int secs) |
| 201 | { |
| 202 | if (secs < 0) |
| 203 | return GPRS_TMR_DEACTIVATED; |
| 204 | if (secs < 2 * 32) |
| 205 | return GPRS_TMR_2SECONDS | (secs / 2); |
| 206 | if (secs < 60 * 2) |
| 207 | /* Ensure monotonicity */ |
| 208 | return GPRS_TMR_2SECONDS | GPRS_TMR_FACT_MASK; |
| 209 | if (secs < 60 * 32) |
| 210 | return GPRS_TMR_MINUTE | (secs / 60); |
| 211 | if (secs < 360 * 6) |
| 212 | /* Ensure monotonicity */ |
| 213 | return GPRS_TMR_MINUTE | GPRS_TMR_FACT_MASK; |
| 214 | if (secs < 360 * 32) |
| 215 | return GPRS_TMR_6MINUTE | (secs / 360); |
| 216 | |
| 217 | return GPRS_TMR_6MINUTE | GPRS_TMR_FACT_MASK; |
| 218 | } |
| 219 | |
Jacob Erlbeck | cf11e93 | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 220 | /* GSM 04.08, 10.5.1.4 */ |
| 221 | int gprs_is_mi_tmsi(const uint8_t *value, size_t value_len) |
| 222 | { |
| 223 | if (value_len != GSM48_TMSI_LEN) |
| 224 | return 0; |
| 225 | |
| 226 | if (!value || (value[0] & GSM_MI_TYPE_MASK) != GSM_MI_TYPE_TMSI) |
| 227 | return 0; |
| 228 | |
| 229 | return 1; |
| 230 | } |
| 231 | |
| 232 | /* GSM 04.08, 10.5.1.4 */ |
| 233 | int gprs_is_mi_imsi(const uint8_t *value, size_t value_len) |
| 234 | { |
| 235 | if (value_len == 0) |
| 236 | return 0; |
| 237 | |
| 238 | if (!value || (value[0] & GSM_MI_TYPE_MASK) != GSM_MI_TYPE_IMSI) |
| 239 | return 0; |
| 240 | |
| 241 | return 1; |
| 242 | } |
| 243 | |
| 244 | int gprs_parse_mi_tmsi(const uint8_t *value, size_t value_len, uint32_t *tmsi) |
| 245 | { |
| 246 | uint32_t tmsi_be; |
| 247 | |
| 248 | if (!gprs_is_mi_tmsi(value, value_len)) |
| 249 | return 0; |
| 250 | |
| 251 | memcpy(&tmsi_be, value + 1, sizeof(tmsi_be)); |
| 252 | |
| 253 | *tmsi = ntohl(tmsi_be); |
| 254 | return 1; |
| 255 | } |
| 256 | |
Jacob Erlbeck | 17608c6 | 2014-10-02 16:14:47 +0200 | [diff] [blame] | 257 | void gprs_parse_tmsi(const uint8_t *value, uint32_t *tmsi) |
| 258 | { |
| 259 | uint32_t tmsi_be; |
| 260 | |
| 261 | memcpy(&tmsi_be, value, sizeof(tmsi_be)); |
| 262 | |
| 263 | *tmsi = ntohl(tmsi_be); |
| 264 | } |
Jacob Erlbeck | dce4501 | 2014-12-11 11:01:46 +0100 | [diff] [blame] | 265 | |
| 266 | /* TODO: Move shift functions to libosmocore */ |
| 267 | |
| 268 | int gprs_shift_v_fixed(uint8_t **data, size_t *data_len, |
| 269 | size_t len, uint8_t **value) |
| 270 | { |
| 271 | if (len > *data_len) |
| 272 | goto fail; |
| 273 | |
| 274 | if (value) |
| 275 | *value = *data; |
| 276 | |
| 277 | *data += len; |
| 278 | *data_len -= len; |
| 279 | |
| 280 | return len; |
| 281 | |
| 282 | fail: |
| 283 | *data += *data_len; |
| 284 | *data_len = 0; |
| 285 | return -1; |
| 286 | } |
| 287 | |
| 288 | int gprs_match_tv_fixed(uint8_t **data, size_t *data_len, |
| 289 | uint8_t tag, size_t len, |
| 290 | uint8_t **value) |
| 291 | { |
| 292 | size_t ie_len; |
| 293 | |
| 294 | if (*data_len == 0) |
| 295 | goto fail; |
| 296 | |
| 297 | if ((*data)[0] != tag) |
| 298 | return 0; |
| 299 | |
| 300 | if (len > *data_len - 1) |
| 301 | goto fail; |
| 302 | |
| 303 | if (value) |
| 304 | *value = *data + 1; |
| 305 | |
| 306 | ie_len = len + 1; |
| 307 | *data += ie_len; |
| 308 | *data_len -= ie_len; |
| 309 | |
| 310 | return ie_len; |
| 311 | |
| 312 | fail: |
| 313 | *data += *data_len; |
| 314 | *data_len = 0; |
| 315 | return -1; |
| 316 | } |
| 317 | |
| 318 | int gprs_match_tlv(uint8_t **data, size_t *data_len, |
Jacob Erlbeck | 96b81da | 2014-12-11 12:05:29 +0100 | [diff] [blame] | 319 | uint8_t expected_tag, uint8_t **value, size_t *value_len) |
| 320 | { |
| 321 | int rc; |
| 322 | uint8_t tag; |
| 323 | uint8_t *old_data = *data; |
| 324 | size_t old_data_len = *data_len; |
| 325 | |
| 326 | rc = gprs_shift_tlv(data, data_len, &tag, value, value_len); |
| 327 | |
| 328 | if (rc > 0 && tag != expected_tag) { |
| 329 | *data = old_data; |
| 330 | *data_len = old_data_len; |
| 331 | return 0; |
| 332 | } |
| 333 | |
| 334 | return rc; |
| 335 | } |
| 336 | |
| 337 | int gprs_shift_tlv(uint8_t **data, size_t *data_len, |
| 338 | uint8_t *tag, uint8_t **value, size_t *value_len) |
Jacob Erlbeck | dce4501 | 2014-12-11 11:01:46 +0100 | [diff] [blame] | 339 | { |
| 340 | size_t len; |
| 341 | size_t ie_len; |
| 342 | |
| 343 | if (*data_len < 2) |
| 344 | goto fail; |
| 345 | |
Jacob Erlbeck | dce4501 | 2014-12-11 11:01:46 +0100 | [diff] [blame] | 346 | len = (*data)[1]; |
| 347 | if (len > *data_len - 2) |
| 348 | goto fail; |
| 349 | |
Jacob Erlbeck | 96b81da | 2014-12-11 12:05:29 +0100 | [diff] [blame] | 350 | if (tag) |
| 351 | *tag = (*data)[0]; |
Jacob Erlbeck | dce4501 | 2014-12-11 11:01:46 +0100 | [diff] [blame] | 352 | if (value) |
| 353 | *value = *data + 2; |
| 354 | if (value_len) |
| 355 | *value_len = len; |
| 356 | |
| 357 | ie_len = len + 2; |
| 358 | |
| 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 | int gprs_shift_lv(uint8_t **data, size_t *data_len, |
| 371 | uint8_t **value, size_t *value_len) |
| 372 | { |
| 373 | size_t len; |
| 374 | size_t ie_len; |
| 375 | |
| 376 | if (*data_len < 1) |
| 377 | goto fail; |
| 378 | |
| 379 | len = (*data)[0]; |
| 380 | if (len > *data_len - 1) |
| 381 | goto fail; |
| 382 | |
| 383 | if (value) |
| 384 | *value = *data + 1; |
| 385 | if (value_len) |
| 386 | *value_len = len; |
| 387 | |
| 388 | ie_len = len + 1; |
| 389 | *data += ie_len; |
| 390 | *data_len -= ie_len; |
| 391 | |
| 392 | return ie_len; |
| 393 | |
| 394 | fail: |
| 395 | *data += *data_len; |
| 396 | *data_len = 0; |
| 397 | return -1; |
| 398 | } |
| 399 | |