Jacob Erlbeck | ef8e30a | 2014-12-11 16:54:14 +0100 | [diff] [blame] | 1 | /* GPRS Subscriber Update Protocol message encoder/decoder */ |
| 2 | |
| 3 | /* |
| 4 | * (C) 2014 by Sysmocom s.f.m.c. GmbH |
Holger Hans Peter Freyther | 0466274 | 2015-04-22 23:09:41 -0400 | [diff] [blame] | 5 | * (C) 2015 by Holger Hans Peter Freyther |
Jacob Erlbeck | ef8e30a | 2014-12-11 16:54:14 +0100 | [diff] [blame] | 6 | * All Rights Reserved |
| 7 | * |
| 8 | * Author: Jacob Erlbeck |
| 9 | * |
| 10 | * This program is free software; you can redistribute it and/or modify |
| 11 | * it under the terms of the GNU Affero General Public License as published by |
| 12 | * the Free Software Foundation; either version 3 of the License, or |
| 13 | * (at your option) any later version. |
| 14 | * |
| 15 | * This program is distributed in the hope that it will be useful, |
| 16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 18 | * GNU Affero General Public License for more details. |
| 19 | * |
| 20 | * You should have received a copy of the GNU Affero General Public License |
| 21 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 22 | * |
| 23 | */ |
| 24 | |
| 25 | #include <openbsc/gprs_gsup_messages.h> |
| 26 | |
| 27 | #include <openbsc/debug.h> |
| 28 | #include <openbsc/gprs_utils.h> |
| 29 | |
| 30 | #include <osmocom/gsm/tlv.h> |
| 31 | #include <osmocom/core/msgb.h> |
| 32 | |
| 33 | #include <stdint.h> |
| 34 | |
| 35 | |
| 36 | static uint64_t decode_big_endian(const uint8_t *data, size_t data_len) |
| 37 | { |
| 38 | uint64_t value = 0; |
| 39 | |
| 40 | while (data_len > 0) { |
| 41 | value = (value << 8) + *data; |
| 42 | data += 1; |
| 43 | data_len -= 1; |
| 44 | } |
| 45 | |
| 46 | return value; |
| 47 | } |
| 48 | |
| 49 | static uint8_t *encode_big_endian(uint64_t value, size_t data_len) |
| 50 | { |
| 51 | static uint8_t buf[sizeof(uint64_t)]; |
| 52 | int idx; |
| 53 | |
| 54 | OSMO_ASSERT(data_len <= ARRAY_SIZE(buf)); |
| 55 | |
| 56 | for (idx = data_len - 1; idx >= 0; idx--) { |
| 57 | buf[idx] = (uint8_t)value; |
| 58 | value = value >> 8; |
| 59 | } |
| 60 | |
| 61 | return buf; |
| 62 | } |
| 63 | |
| 64 | static int decode_pdp_info(uint8_t *data, size_t data_len, |
| 65 | struct gprs_gsup_pdp_info *pdp_info) |
| 66 | { |
| 67 | int rc; |
| 68 | uint8_t tag; |
| 69 | uint8_t *value; |
| 70 | size_t value_len; |
| 71 | |
| 72 | /* specific parts */ |
| 73 | while (data_len > 0) { |
| 74 | enum gprs_gsup_iei iei; |
| 75 | |
| 76 | rc = gprs_shift_tlv(&data, &data_len, &tag, &value, &value_len); |
| 77 | if (rc < 0) |
Jacob Erlbeck | 092bbc8 | 2015-01-05 18:57:32 +0100 | [diff] [blame] | 78 | return -GMM_CAUSE_PROTO_ERR_UNSPEC; |
Jacob Erlbeck | ef8e30a | 2014-12-11 16:54:14 +0100 | [diff] [blame] | 79 | |
| 80 | iei = tag; |
| 81 | |
| 82 | switch (iei) { |
| 83 | case GPRS_GSUP_PDP_CONTEXT_ID_IE: |
| 84 | pdp_info->context_id = decode_big_endian(value, value_len); |
| 85 | break; |
| 86 | |
| 87 | case GPRS_GSUP_PDP_TYPE_IE: |
| 88 | pdp_info->pdp_type = |
| 89 | decode_big_endian(value, value_len) & 0x0fff; |
| 90 | break; |
| 91 | |
| 92 | case GPRS_GSUP_ACCESS_POINT_NAME_IE: |
| 93 | pdp_info->apn_enc = value; |
| 94 | pdp_info->apn_enc_len = value_len; |
| 95 | break; |
| 96 | |
Holger Hans Peter Freyther | 2944e21 | 2015-04-23 09:13:01 -0400 | [diff] [blame] | 97 | case GPRS_GSUP_PDP_QOS_IE: |
| 98 | pdp_info->qos_enc = value; |
| 99 | pdp_info->qos_enc_len = value_len; |
| 100 | break; |
| 101 | |
Jacob Erlbeck | ef8e30a | 2014-12-11 16:54:14 +0100 | [diff] [blame] | 102 | default: |
| 103 | LOGP(DGPRS, LOGL_ERROR, |
| 104 | "GSUP IE type %d not expected in PDP info\n", iei); |
| 105 | continue; |
| 106 | } |
| 107 | } |
| 108 | |
| 109 | return 0; |
| 110 | } |
| 111 | |
| 112 | static int decode_auth_info(uint8_t *data, size_t data_len, |
| 113 | struct gsm_auth_tuple *auth_tuple) |
| 114 | { |
| 115 | int rc; |
| 116 | uint8_t tag; |
| 117 | uint8_t *value; |
| 118 | size_t value_len; |
| 119 | enum gprs_gsup_iei iei; |
| 120 | |
| 121 | /* specific parts */ |
| 122 | while (data_len > 0) { |
| 123 | rc = gprs_shift_tlv(&data, &data_len, &tag, &value, &value_len); |
| 124 | if (rc < 0) |
Jacob Erlbeck | 092bbc8 | 2015-01-05 18:57:32 +0100 | [diff] [blame] | 125 | return -GMM_CAUSE_PROTO_ERR_UNSPEC; |
Jacob Erlbeck | ef8e30a | 2014-12-11 16:54:14 +0100 | [diff] [blame] | 126 | |
| 127 | iei = tag; |
| 128 | |
| 129 | switch (iei) { |
| 130 | case GPRS_GSUP_RAND_IE: |
| 131 | if (value_len != sizeof(auth_tuple->rand)) |
| 132 | goto parse_error; |
| 133 | |
| 134 | memcpy(auth_tuple->rand, value, value_len); |
| 135 | break; |
| 136 | |
| 137 | case GPRS_GSUP_SRES_IE: |
| 138 | if (value_len != sizeof(auth_tuple->sres)) |
| 139 | goto parse_error; |
| 140 | |
| 141 | memcpy(auth_tuple->sres, value, value_len); |
| 142 | break; |
| 143 | |
| 144 | case GPRS_GSUP_KC_IE: |
| 145 | if (value_len != sizeof(auth_tuple->kc)) |
| 146 | goto parse_error; |
| 147 | |
| 148 | memcpy(auth_tuple->kc, value, value_len); |
| 149 | break; |
| 150 | |
| 151 | default: |
| 152 | LOGP(DGPRS, LOGL_ERROR, |
| 153 | "GSUP IE type %d not expected in PDP info\n", iei); |
| 154 | continue; |
| 155 | } |
| 156 | } |
| 157 | |
| 158 | return 0; |
| 159 | |
| 160 | parse_error: |
| 161 | LOGP(DGPRS, LOGL_ERROR, |
Holger Hans Peter Freyther | 844f4b8 | 2015-04-23 11:55:23 -0400 | [diff] [blame] | 162 | "GSUP IE type %d, length %zu invalid in PDP info\n", iei, value_len); |
Jacob Erlbeck | ef8e30a | 2014-12-11 16:54:14 +0100 | [diff] [blame] | 163 | |
| 164 | return -1; |
| 165 | } |
| 166 | |
| 167 | int gprs_gsup_decode(const uint8_t *const_data, size_t data_len, |
| 168 | struct gprs_gsup_message *gsup_msg) |
| 169 | { |
| 170 | int rc; |
| 171 | uint8_t tag; |
| 172 | /* the shift/match functions expect non-const pointers, but we'll |
| 173 | * either copy the data or cast pointers back to const before returning |
| 174 | * them |
| 175 | */ |
| 176 | uint8_t *data = (uint8_t *)const_data; |
| 177 | uint8_t *value; |
| 178 | size_t value_len; |
| 179 | static const struct gprs_gsup_pdp_info empty_pdp_info = {0}; |
| 180 | static const struct gsm_auth_tuple empty_auth_info = {0}; |
Jacob Erlbeck | 6aa8b45 | 2015-01-12 13:54:39 +0100 | [diff] [blame] | 181 | static const struct gprs_gsup_message empty_gsup_message = {0}; |
| 182 | |
| 183 | *gsup_msg = empty_gsup_message; |
Jacob Erlbeck | ef8e30a | 2014-12-11 16:54:14 +0100 | [diff] [blame] | 184 | |
| 185 | /* generic part */ |
Jacob Erlbeck | e27bc6c | 2015-01-12 13:23:05 +0100 | [diff] [blame] | 186 | rc = gprs_shift_v_fixed(&data, &data_len, 1, &value); |
| 187 | if (rc < 0) |
| 188 | return -GMM_CAUSE_INV_MAND_INFO; |
| 189 | |
Jacob Erlbeck | ef8e30a | 2014-12-11 16:54:14 +0100 | [diff] [blame] | 190 | gsup_msg->message_type = decode_big_endian(value, 1); |
| 191 | |
| 192 | rc = gprs_match_tlv(&data, &data_len, GPRS_GSUP_IMSI_IE, |
| 193 | &value, &value_len); |
| 194 | |
| 195 | if (rc <= 0) |
| 196 | return -GMM_CAUSE_INV_MAND_INFO; |
| 197 | |
| 198 | if (value_len * 2 + 1 > sizeof(gsup_msg->imsi)) |
| 199 | return -GMM_CAUSE_INV_MAND_INFO; |
| 200 | |
| 201 | /* Note that gsm48_decode_bcd_number expects the number of encoded IMSI |
| 202 | * octets in the first octet. By coincidence (the TLV encoding) the byte |
| 203 | * before the value part already contains this length so we can use it |
| 204 | * here. |
| 205 | */ |
| 206 | OSMO_ASSERT(value[-1] == value_len); |
| 207 | gsm48_decode_bcd_number(gsup_msg->imsi, sizeof(gsup_msg->imsi), |
| 208 | value - 1, 0); |
| 209 | |
Jacob Erlbeck | ef8e30a | 2014-12-11 16:54:14 +0100 | [diff] [blame] | 210 | /* specific parts */ |
| 211 | while (data_len > 0) { |
| 212 | enum gprs_gsup_iei iei; |
| 213 | struct gprs_gsup_pdp_info pdp_info; |
| 214 | struct gsm_auth_tuple auth_info; |
| 215 | |
| 216 | rc = gprs_shift_tlv(&data, &data_len, &tag, &value, &value_len); |
| 217 | if (rc < 0) |
| 218 | return -GMM_CAUSE_PROTO_ERR_UNSPEC; |
| 219 | |
| 220 | iei = tag; |
| 221 | |
| 222 | switch (iei) { |
| 223 | case GPRS_GSUP_IMSI_IE: |
| 224 | case GPRS_GSUP_PDP_TYPE_IE: |
| 225 | case GPRS_GSUP_ACCESS_POINT_NAME_IE: |
| 226 | case GPRS_GSUP_RAND_IE: |
| 227 | case GPRS_GSUP_SRES_IE: |
| 228 | case GPRS_GSUP_KC_IE: |
| 229 | LOGP(DGPRS, LOGL_NOTICE, |
| 230 | "GSUP IE type %d not expected (ignored)\n", iei); |
| 231 | continue; |
| 232 | |
| 233 | case GPRS_GSUP_CAUSE_IE: |
| 234 | gsup_msg->cause = decode_big_endian(value, value_len); |
| 235 | break; |
| 236 | |
| 237 | case GPRS_GSUP_CANCEL_TYPE_IE: |
| 238 | gsup_msg->cancel_type = |
| 239 | decode_big_endian(value, value_len) + 1; |
| 240 | break; |
| 241 | |
| 242 | case GPRS_GSUP_PDP_INFO_COMPL_IE: |
| 243 | gsup_msg->pdp_info_compl = 1; |
| 244 | break; |
| 245 | |
Jacob Erlbeck | cd1b055 | 2015-01-15 11:50:08 +0100 | [diff] [blame] | 246 | case GPRS_GSUP_FREEZE_PTMSI_IE: |
| 247 | gsup_msg->freeze_ptmsi = 1; |
| 248 | break; |
| 249 | |
Jacob Erlbeck | ef8e30a | 2014-12-11 16:54:14 +0100 | [diff] [blame] | 250 | case GPRS_GSUP_PDP_CONTEXT_ID_IE: |
| 251 | /* When these IE appear in the top-level part of the |
| 252 | * message, they are used by Delete Subscr Info to delete |
| 253 | * single entries. We don't have an extra list for |
| 254 | * these but use the PDP info list instead */ |
| 255 | |
| 256 | /* fall through */ |
| 257 | |
| 258 | case GPRS_GSUP_PDP_INFO_IE: |
| 259 | if (gsup_msg->num_pdp_infos >= GPRS_GSUP_MAX_NUM_PDP_INFO) { |
| 260 | LOGP(DGPRS, LOGL_ERROR, |
| 261 | "GSUP IE type %d (PDP_INFO) max exceeded\n", |
| 262 | iei); |
| 263 | return -GMM_CAUSE_COND_IE_ERR; |
| 264 | } |
| 265 | |
Jacob Erlbeck | 6aa8b45 | 2015-01-12 13:54:39 +0100 | [diff] [blame] | 266 | pdp_info = empty_pdp_info; |
Jacob Erlbeck | ef8e30a | 2014-12-11 16:54:14 +0100 | [diff] [blame] | 267 | |
| 268 | if (iei == GPRS_GSUP_PDP_INFO_IE) { |
| 269 | rc = decode_pdp_info(value, value_len, &pdp_info); |
| 270 | if (rc < 0) |
| 271 | return rc; |
| 272 | pdp_info.have_info = 1; |
| 273 | } else { |
| 274 | pdp_info.context_id = |
| 275 | decode_big_endian(value, value_len); |
| 276 | } |
| 277 | |
| 278 | gsup_msg->pdp_infos[gsup_msg->num_pdp_infos++] = |
| 279 | pdp_info; |
| 280 | break; |
| 281 | |
| 282 | case GPRS_GSUP_AUTH_TUPLE_IE: |
| 283 | if (gsup_msg->num_auth_tuples >= GPRS_GSUP_MAX_NUM_AUTH_INFO) { |
| 284 | LOGP(DGPRS, LOGL_ERROR, |
| 285 | "GSUP IE type %d (AUTH_INFO) max exceeded\n", |
| 286 | iei); |
| 287 | return -GMM_CAUSE_INV_MAND_INFO; |
| 288 | } |
| 289 | |
Jacob Erlbeck | 6aa8b45 | 2015-01-12 13:54:39 +0100 | [diff] [blame] | 290 | auth_info = empty_auth_info; |
Jacob Erlbeck | ef8e30a | 2014-12-11 16:54:14 +0100 | [diff] [blame] | 291 | auth_info.key_seq = gsup_msg->num_auth_tuples; |
| 292 | |
| 293 | rc = decode_auth_info(value, value_len, &auth_info); |
| 294 | if (rc < 0) |
| 295 | return rc; |
| 296 | |
| 297 | gsup_msg->auth_tuples[gsup_msg->num_auth_tuples++] = |
| 298 | auth_info; |
| 299 | break; |
Holger Hans Peter Freyther | 0466274 | 2015-04-22 23:09:41 -0400 | [diff] [blame] | 300 | |
| 301 | case GPRS_GSUP_MSISDN_IE: |
| 302 | gsup_msg->msisdn_enc = value; |
| 303 | gsup_msg->msisdn_enc_len = value_len; |
| 304 | break; |
| 305 | |
Jacob Erlbeck | ef8e30a | 2014-12-11 16:54:14 +0100 | [diff] [blame] | 306 | default: |
| 307 | LOGP(DGPRS, LOGL_NOTICE, |
| 308 | "GSUP IE type %d unknown\n", iei); |
| 309 | continue; |
| 310 | } |
| 311 | } |
| 312 | |
| 313 | return 0; |
| 314 | } |
| 315 | |
| 316 | static void encode_pdp_info(struct msgb *msg, enum gprs_gsup_iei iei, |
| 317 | const struct gprs_gsup_pdp_info *pdp_info) |
| 318 | { |
| 319 | uint8_t *len_field; |
| 320 | size_t old_len; |
| 321 | uint8_t u8; |
| 322 | |
| 323 | len_field = msgb_tlv_put(msg, iei, 0, NULL) - 1; |
| 324 | old_len = msgb_length(msg); |
| 325 | |
| 326 | u8 = pdp_info->context_id; |
| 327 | msgb_tlv_put(msg, GPRS_GSUP_PDP_CONTEXT_ID_IE, sizeof(u8), &u8); |
| 328 | |
| 329 | if (pdp_info->pdp_type) { |
| 330 | msgb_tlv_put(msg, GPRS_GSUP_PDP_TYPE_IE, |
| 331 | GPRS_GSUP_PDP_TYPE_SIZE, |
| 332 | encode_big_endian(pdp_info->pdp_type | 0xf000, |
| 333 | GPRS_GSUP_PDP_TYPE_SIZE)); |
| 334 | } |
| 335 | |
| 336 | if (pdp_info->apn_enc) { |
| 337 | msgb_tlv_put(msg, GPRS_GSUP_ACCESS_POINT_NAME_IE, |
| 338 | pdp_info->apn_enc_len, pdp_info->apn_enc); |
| 339 | } |
| 340 | |
Holger Hans Peter Freyther | 2944e21 | 2015-04-23 09:13:01 -0400 | [diff] [blame] | 341 | if (pdp_info->qos_enc) { |
| 342 | msgb_tlv_put(msg, GPRS_GSUP_PDP_QOS_IE, |
| 343 | pdp_info->qos_enc_len, pdp_info->qos_enc); |
| 344 | } |
| 345 | |
Jacob Erlbeck | ef8e30a | 2014-12-11 16:54:14 +0100 | [diff] [blame] | 346 | /* Update length field */ |
| 347 | *len_field = msgb_length(msg) - old_len; |
| 348 | } |
| 349 | |
| 350 | static void encode_auth_info(struct msgb *msg, enum gprs_gsup_iei iei, |
| 351 | const struct gsm_auth_tuple *auth_tuple) |
| 352 | { |
| 353 | uint8_t *len_field; |
| 354 | size_t old_len; |
| 355 | |
| 356 | len_field = msgb_tlv_put(msg, iei, 0, NULL) - 1; |
| 357 | old_len = msgb_length(msg); |
| 358 | |
| 359 | msgb_tlv_put(msg, GPRS_GSUP_RAND_IE, |
| 360 | sizeof(auth_tuple->rand), auth_tuple->rand); |
| 361 | |
| 362 | msgb_tlv_put(msg, GPRS_GSUP_SRES_IE, |
| 363 | sizeof(auth_tuple->sres), auth_tuple->sres); |
| 364 | |
| 365 | msgb_tlv_put(msg, GPRS_GSUP_KC_IE, |
| 366 | sizeof(auth_tuple->kc), auth_tuple->kc); |
| 367 | |
| 368 | /* Update length field */ |
| 369 | *len_field = msgb_length(msg) - old_len; |
| 370 | } |
| 371 | |
| 372 | void gprs_gsup_encode(struct msgb *msg, const struct gprs_gsup_message *gsup_msg) |
| 373 | { |
| 374 | uint8_t u8; |
| 375 | int idx; |
| 376 | uint8_t bcd_buf[GSM48_MI_SIZE] = {0}; |
| 377 | size_t bcd_len; |
| 378 | |
| 379 | /* generic part */ |
| 380 | OSMO_ASSERT(gsup_msg->message_type); |
| 381 | msgb_v_put(msg, gsup_msg->message_type); |
| 382 | |
| 383 | bcd_len = gsm48_encode_bcd_number(bcd_buf, sizeof(bcd_buf), 0, |
| 384 | gsup_msg->imsi); |
| 385 | |
| 386 | OSMO_ASSERT(bcd_len > 1); |
| 387 | |
| 388 | /* Note that gsm48_encode_bcd_number puts the length into the first |
| 389 | * octet. Since msgb_tlv_put will add this length byte, we'll have to |
| 390 | * skip it */ |
| 391 | msgb_tlv_put(msg, GPRS_GSUP_IMSI_IE, bcd_len - 1, &bcd_buf[1]); |
| 392 | |
| 393 | /* specific parts */ |
Holger Hans Peter Freyther | 0466274 | 2015-04-22 23:09:41 -0400 | [diff] [blame] | 394 | if (gsup_msg->msisdn_enc) |
| 395 | msgb_tlv_put(msg, GPRS_GSUP_MSISDN_IE, |
| 396 | gsup_msg->msisdn_enc_len, gsup_msg->msisdn_enc); |
| 397 | |
Jacob Erlbeck | ef8e30a | 2014-12-11 16:54:14 +0100 | [diff] [blame] | 398 | if ((u8 = gsup_msg->cause)) |
| 399 | msgb_tlv_put(msg, GPRS_GSUP_CAUSE_IE, sizeof(u8), &u8); |
| 400 | |
| 401 | if ((u8 = gsup_msg->cancel_type)) { |
| 402 | u8 -= 1; |
| 403 | msgb_tlv_put(msg, GPRS_GSUP_CANCEL_TYPE_IE, sizeof(u8), &u8); |
| 404 | } |
| 405 | |
| 406 | if (gsup_msg->pdp_info_compl) |
| 407 | msgb_tlv_put(msg, GPRS_GSUP_PDP_INFO_COMPL_IE, 0, &u8); |
| 408 | |
Jacob Erlbeck | cd1b055 | 2015-01-15 11:50:08 +0100 | [diff] [blame] | 409 | if (gsup_msg->freeze_ptmsi) |
| 410 | msgb_tlv_put(msg, GPRS_GSUP_FREEZE_PTMSI_IE, 0, &u8); |
| 411 | |
Jacob Erlbeck | ef8e30a | 2014-12-11 16:54:14 +0100 | [diff] [blame] | 412 | for (idx = 0; idx < gsup_msg->num_pdp_infos; idx++) { |
| 413 | const struct gprs_gsup_pdp_info *pdp_info; |
| 414 | |
| 415 | pdp_info = &gsup_msg->pdp_infos[idx]; |
| 416 | |
| 417 | if (pdp_info->context_id == 0) |
| 418 | continue; |
| 419 | |
| 420 | if (pdp_info->have_info) { |
| 421 | encode_pdp_info(msg, GPRS_GSUP_PDP_INFO_IE, pdp_info); |
| 422 | } else { |
| 423 | u8 = pdp_info->context_id; |
| 424 | msgb_tlv_put(msg, GPRS_GSUP_PDP_CONTEXT_ID_IE, |
| 425 | sizeof(u8), &u8); |
| 426 | } |
| 427 | } |
| 428 | |
| 429 | for (idx = 0; idx < gsup_msg->num_auth_tuples; idx++) { |
| 430 | const struct gsm_auth_tuple *auth_info; |
| 431 | |
| 432 | auth_info = &gsup_msg->auth_tuples[idx]; |
| 433 | |
| 434 | if (auth_info->key_seq == GSM_KEY_SEQ_INVAL) |
| 435 | continue; |
| 436 | |
| 437 | encode_auth_info(msg, GPRS_GSUP_AUTH_TUPLE_IE, auth_info); |
| 438 | } |
| 439 | } |