Holger Hans Peter Freyther | 7127b02 | 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> |
| 23 | |
| 24 | #include <osmocom/core/msgb.h> |
| 25 | #include <osmocom/gprs/gprs_ns.h> |
| 26 | |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 27 | #include <osmocom/gsm/protocol/gsm_04_08.h> |
| 28 | |
Holger Hans Peter Freyther | 7127b02 | 2014-08-04 11:52:52 +0200 | [diff] [blame] | 29 | #include <string.h> |
| 30 | |
| 31 | /* FIXME: this needs to go to libosmocore/msgb.c */ |
| 32 | struct msgb *gprs_msgb_copy(const struct msgb *msg, const char *name) |
| 33 | { |
| 34 | struct libgb_msgb_cb *old_cb, *new_cb; |
| 35 | struct msgb *new_msg; |
| 36 | |
| 37 | new_msg = msgb_alloc(msg->data_len, name); |
| 38 | if (!new_msg) |
| 39 | return NULL; |
| 40 | |
| 41 | /* copy data */ |
| 42 | memcpy(new_msg->_data, msg->_data, new_msg->data_len); |
| 43 | |
| 44 | /* copy header */ |
| 45 | new_msg->len = msg->len; |
| 46 | new_msg->data += msg->data - msg->_data; |
| 47 | new_msg->head += msg->head - msg->_data; |
| 48 | new_msg->tail += msg->tail - msg->_data; |
| 49 | |
Jacob Erlbeck | 7e31f84 | 2014-09-22 18:50:08 +0200 | [diff] [blame] | 50 | if (msg->l1h) |
| 51 | new_msg->l1h = new_msg->_data + (msg->l1h - msg->_data); |
| 52 | if (msg->l2h) |
| 53 | new_msg->l2h = new_msg->_data + (msg->l2h - msg->_data); |
| 54 | if (msg->l3h) |
| 55 | new_msg->l3h = new_msg->_data + (msg->l3h - msg->_data); |
| 56 | if (msg->l4h) |
| 57 | new_msg->l4h = new_msg->_data + (msg->l4h - msg->_data); |
Holger Hans Peter Freyther | 7127b02 | 2014-08-04 11:52:52 +0200 | [diff] [blame] | 58 | |
| 59 | /* copy GB specific data */ |
| 60 | old_cb = LIBGB_MSGB_CB(msg); |
| 61 | new_cb = LIBGB_MSGB_CB(new_msg); |
| 62 | |
Jacob Erlbeck | 7e31f84 | 2014-09-22 18:50:08 +0200 | [diff] [blame] | 63 | if (old_cb->bssgph) |
| 64 | new_cb->bssgph = new_msg->_data + (old_cb->bssgph - msg->_data); |
| 65 | if (old_cb->llch) |
| 66 | new_cb->llch = new_msg->_data + (old_cb->llch - msg->_data); |
Holger Hans Peter Freyther | 7127b02 | 2014-08-04 11:52:52 +0200 | [diff] [blame] | 67 | |
| 68 | /* bssgp_cell_id is a pointer into the old msgb, so we need to make |
| 69 | * it a pointer into the new msgb */ |
Jacob Erlbeck | 7e31f84 | 2014-09-22 18:50:08 +0200 | [diff] [blame] | 70 | if (old_cb->bssgp_cell_id) |
| 71 | new_cb->bssgp_cell_id = new_msg->_data + |
| 72 | (old_cb->bssgp_cell_id - msg->_data); |
Holger Hans Peter Freyther | 7127b02 | 2014-08-04 11:52:52 +0200 | [diff] [blame] | 73 | new_cb->nsei = old_cb->nsei; |
| 74 | new_cb->bvci = old_cb->bvci; |
| 75 | new_cb->tlli = old_cb->tlli; |
| 76 | |
| 77 | return new_msg; |
| 78 | } |
| 79 | |
| 80 | /* TODO: Move this to libosmocore/msgb.c */ |
| 81 | int gprs_msgb_resize_area(struct msgb *msg, uint8_t *area, |
| 82 | size_t old_size, size_t new_size) |
| 83 | { |
| 84 | int rc; |
| 85 | uint8_t *rest = area + old_size; |
| 86 | int rest_len = msg->len - old_size - (area - msg->data); |
| 87 | int delta_size = (int)new_size - (int)old_size; |
| 88 | |
| 89 | if (delta_size == 0) |
| 90 | return 0; |
| 91 | |
| 92 | if (delta_size > 0) { |
| 93 | rc = msgb_trim(msg, msg->len + delta_size); |
| 94 | if (rc < 0) |
| 95 | return rc; |
| 96 | } |
| 97 | |
| 98 | memmove(area + new_size, area + old_size, rest_len); |
| 99 | |
| 100 | if (msg->l1h >= rest) |
| 101 | msg->l1h += delta_size; |
| 102 | if (msg->l2h >= rest) |
| 103 | msg->l2h += delta_size; |
| 104 | if (msg->l3h >= rest) |
| 105 | msg->l3h += delta_size; |
| 106 | if (msg->l4h >= rest) |
| 107 | msg->l4h += delta_size; |
| 108 | |
| 109 | if (delta_size < 0) |
| 110 | msgb_trim(msg, msg->len + delta_size); |
| 111 | |
| 112 | return 0; |
| 113 | } |
| 114 | |
| 115 | /* TODO: Move these conversion functions to a utils file. */ |
Holger Hans Peter Freyther | ce1b22e | 2014-08-04 14:22:13 +0200 | [diff] [blame] | 116 | /** |
| 117 | * out_str needs to have rest_chars amount of bytes or 1 whatever is bigger. |
| 118 | */ |
Holger Hans Peter Freyther | 7127b02 | 2014-08-04 11:52:52 +0200 | [diff] [blame] | 119 | char * gprs_apn_to_str(char *out_str, const uint8_t *apn_enc, size_t rest_chars) |
| 120 | { |
| 121 | char *str = out_str; |
| 122 | |
| 123 | while (rest_chars > 0 && apn_enc[0]) { |
| 124 | size_t label_size = apn_enc[0]; |
| 125 | if (label_size + 1 > rest_chars) |
| 126 | return NULL; |
| 127 | |
| 128 | memmove(str, apn_enc + 1, label_size); |
| 129 | str += label_size; |
| 130 | rest_chars -= label_size + 1; |
| 131 | apn_enc += label_size + 1; |
| 132 | |
| 133 | if (rest_chars) |
| 134 | *(str++) = '.'; |
| 135 | } |
| 136 | str[0] = '\0'; |
| 137 | |
| 138 | return out_str; |
| 139 | } |
| 140 | |
Holger Hans Peter Freyther | ce1b22e | 2014-08-04 14:22:13 +0200 | [diff] [blame] | 141 | int gprs_str_to_apn(uint8_t *apn_enc, size_t max_len, const char *str) |
Holger Hans Peter Freyther | 7127b02 | 2014-08-04 11:52:52 +0200 | [diff] [blame] | 142 | { |
Holger Hans Peter Freyther | ce1b22e | 2014-08-04 14:22:13 +0200 | [diff] [blame] | 143 | uint8_t *last_len_field; |
| 144 | int len; |
| 145 | |
| 146 | /* Can we even write the length field to the output? */ |
| 147 | if (max_len == 0) |
| 148 | return -1; |
| 149 | |
| 150 | /* Remember where we need to put the length once we know it */ |
| 151 | last_len_field = apn_enc; |
| 152 | len = 1; |
Holger Hans Peter Freyther | 7127b02 | 2014-08-04 11:52:52 +0200 | [diff] [blame] | 153 | apn_enc += 1; |
| 154 | |
| 155 | while (str[0]) { |
Holger Hans Peter Freyther | ce1b22e | 2014-08-04 14:22:13 +0200 | [diff] [blame] | 156 | if (len >= max_len) |
| 157 | return -1; |
| 158 | |
Holger Hans Peter Freyther | 7127b02 | 2014-08-04 11:52:52 +0200 | [diff] [blame] | 159 | if (str[0] == '.') { |
| 160 | *last_len_field = (apn_enc - last_len_field) - 1; |
| 161 | last_len_field = apn_enc; |
| 162 | } else { |
| 163 | *apn_enc = str[0]; |
| 164 | } |
| 165 | apn_enc += 1; |
| 166 | str += 1; |
| 167 | len += 1; |
Holger Hans Peter Freyther | 7127b02 | 2014-08-04 11:52:52 +0200 | [diff] [blame] | 168 | } |
| 169 | |
| 170 | *last_len_field = (apn_enc - last_len_field) - 1; |
| 171 | |
| 172 | return len; |
| 173 | } |
| 174 | |
Jacob Erlbeck | 9114bee | 2014-08-19 12:21:01 +0200 | [diff] [blame] | 175 | /* GSM 04.08, 10.5.1.4 */ |
| 176 | int gprs_is_mi_tmsi(const uint8_t *value, size_t value_len) |
| 177 | { |
| 178 | if (value_len != GSM48_TMSI_LEN) |
| 179 | return 0; |
| 180 | |
| 181 | if (!value || (value[0] & GSM_MI_TYPE_MASK) != GSM_MI_TYPE_TMSI) |
| 182 | return 0; |
| 183 | |
| 184 | return 1; |
| 185 | } |
| 186 | |
| 187 | /* GSM 04.08, 10.5.1.4 */ |
| 188 | int gprs_is_mi_imsi(const uint8_t *value, size_t value_len) |
| 189 | { |
| 190 | if (value_len == 0) |
| 191 | return 0; |
| 192 | |
| 193 | if (!value || (value[0] & GSM_MI_TYPE_MASK) != GSM_MI_TYPE_IMSI) |
| 194 | return 0; |
| 195 | |
| 196 | return 1; |
| 197 | } |
| 198 | |
| 199 | int gprs_parse_mi_tmsi(const uint8_t *value, size_t value_len, uint32_t *tmsi) |
| 200 | { |
| 201 | uint32_t tmsi_be; |
| 202 | |
| 203 | if (!gprs_is_mi_tmsi(value, value_len)) |
| 204 | return 0; |
| 205 | |
| 206 | memcpy(&tmsi_be, value + 1, sizeof(tmsi_be)); |
| 207 | |
| 208 | *tmsi = ntohl(tmsi_be); |
| 209 | return 1; |
| 210 | } |
| 211 | |
Jacob Erlbeck | 4938917 | 2014-10-02 16:14:47 +0200 | [diff] [blame] | 212 | void gprs_parse_tmsi(const uint8_t *value, uint32_t *tmsi) |
| 213 | { |
| 214 | uint32_t tmsi_be; |
| 215 | |
| 216 | memcpy(&tmsi_be, value, sizeof(tmsi_be)); |
| 217 | |
| 218 | *tmsi = ntohl(tmsi_be); |
| 219 | } |
Jacob Erlbeck | dcfd456 | 2014-12-11 11:01:46 +0100 | [diff] [blame] | 220 | |
| 221 | /* TODO: Move shift functions to libosmocore */ |
| 222 | |
| 223 | int gprs_shift_v_fixed(uint8_t **data, size_t *data_len, |
| 224 | size_t len, uint8_t **value) |
| 225 | { |
| 226 | if (len > *data_len) |
| 227 | goto fail; |
| 228 | |
| 229 | if (value) |
| 230 | *value = *data; |
| 231 | |
| 232 | *data += len; |
| 233 | *data_len -= len; |
| 234 | |
| 235 | return len; |
| 236 | |
| 237 | fail: |
| 238 | *data += *data_len; |
| 239 | *data_len = 0; |
| 240 | return -1; |
| 241 | } |
| 242 | |
| 243 | int gprs_match_tv_fixed(uint8_t **data, size_t *data_len, |
| 244 | uint8_t tag, size_t len, |
| 245 | uint8_t **value) |
| 246 | { |
| 247 | size_t ie_len; |
| 248 | |
| 249 | if (*data_len == 0) |
| 250 | goto fail; |
| 251 | |
| 252 | if ((*data)[0] != tag) |
| 253 | return 0; |
| 254 | |
| 255 | if (len > *data_len - 1) |
| 256 | goto fail; |
| 257 | |
| 258 | if (value) |
| 259 | *value = *data + 1; |
| 260 | |
| 261 | ie_len = len + 1; |
| 262 | *data += ie_len; |
| 263 | *data_len -= ie_len; |
| 264 | |
| 265 | return ie_len; |
| 266 | |
| 267 | fail: |
| 268 | *data += *data_len; |
| 269 | *data_len = 0; |
| 270 | return -1; |
| 271 | } |
| 272 | |
| 273 | int gprs_match_tlv(uint8_t **data, size_t *data_len, |
Jacob Erlbeck | 697a534 | 2014-12-11 12:05:29 +0100 | [diff] [blame] | 274 | uint8_t expected_tag, uint8_t **value, size_t *value_len) |
| 275 | { |
| 276 | int rc; |
| 277 | uint8_t tag; |
| 278 | uint8_t *old_data = *data; |
| 279 | size_t old_data_len = *data_len; |
| 280 | |
| 281 | rc = gprs_shift_tlv(data, data_len, &tag, value, value_len); |
| 282 | |
| 283 | if (rc > 0 && tag != expected_tag) { |
| 284 | *data = old_data; |
| 285 | *data_len = old_data_len; |
| 286 | return 0; |
| 287 | } |
| 288 | |
| 289 | return rc; |
| 290 | } |
| 291 | |
| 292 | int gprs_shift_tlv(uint8_t **data, size_t *data_len, |
| 293 | uint8_t *tag, uint8_t **value, size_t *value_len) |
Jacob Erlbeck | dcfd456 | 2014-12-11 11:01:46 +0100 | [diff] [blame] | 294 | { |
| 295 | size_t len; |
| 296 | size_t ie_len; |
| 297 | |
| 298 | if (*data_len < 2) |
| 299 | goto fail; |
| 300 | |
Jacob Erlbeck | dcfd456 | 2014-12-11 11:01:46 +0100 | [diff] [blame] | 301 | len = (*data)[1]; |
| 302 | if (len > *data_len - 2) |
| 303 | goto fail; |
| 304 | |
Jacob Erlbeck | 697a534 | 2014-12-11 12:05:29 +0100 | [diff] [blame] | 305 | if (tag) |
| 306 | *tag = (*data)[0]; |
Jacob Erlbeck | dcfd456 | 2014-12-11 11:01:46 +0100 | [diff] [blame] | 307 | if (value) |
| 308 | *value = *data + 2; |
| 309 | if (value_len) |
| 310 | *value_len = len; |
| 311 | |
| 312 | ie_len = len + 2; |
| 313 | |
| 314 | *data += ie_len; |
| 315 | *data_len -= ie_len; |
| 316 | |
| 317 | return ie_len; |
| 318 | |
| 319 | fail: |
| 320 | *data += *data_len; |
| 321 | *data_len = 0; |
| 322 | return -1; |
| 323 | } |
| 324 | |
| 325 | int gprs_shift_lv(uint8_t **data, size_t *data_len, |
| 326 | uint8_t **value, size_t *value_len) |
| 327 | { |
| 328 | size_t len; |
| 329 | size_t ie_len; |
| 330 | |
| 331 | if (*data_len < 1) |
| 332 | goto fail; |
| 333 | |
| 334 | len = (*data)[0]; |
| 335 | if (len > *data_len - 1) |
| 336 | goto fail; |
| 337 | |
| 338 | if (value) |
| 339 | *value = *data + 1; |
| 340 | if (value_len) |
| 341 | *value_len = len; |
| 342 | |
| 343 | ie_len = len + 1; |
| 344 | *data += ie_len; |
| 345 | *data_len -= ie_len; |
| 346 | |
| 347 | return ie_len; |
| 348 | |
| 349 | fail: |
| 350 | *data += *data_len; |
| 351 | *data_len = 0; |
| 352 | return -1; |
| 353 | } |
| 354 | |