Holger Hans Peter Freyther | d11290b | 2013-10-26 17:32:04 +0200 | [diff] [blame] | 1 | /* decoding |
| 2 | * |
| 3 | * Copyright (C) 2012 Ivan Klyuchnikov |
| 4 | * Copyright (C) 2012 Andreas Eversberg <jolly@eversberg.eu> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public License |
| 8 | * as published by the Free Software Foundation; either version 2 |
| 9 | * of the License, or (at your option) any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU General Public License |
| 17 | * along with this program; if not, write to the Free Software |
| 18 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 19 | */ |
| 20 | #include <decoding.h> |
| 21 | #include <rlc.h> |
| 22 | #include <gprs_debug.h> |
| 23 | |
Jacob Erlbeck | 4abc686 | 2015-12-08 15:14:05 +0100 | [diff] [blame] | 24 | extern "C" { |
| 25 | #include <osmocom/core/utils.h> |
Jacob Erlbeck | 3fdcb2b | 2016-01-18 16:51:59 +0100 | [diff] [blame] | 26 | #include <osmocom/core/bitcomp.h> |
Jacob Erlbeck | 4abc686 | 2015-12-08 15:14:05 +0100 | [diff] [blame] | 27 | } |
| 28 | |
Holger Hans Peter Freyther | d11290b | 2013-10-26 17:32:04 +0200 | [diff] [blame] | 29 | #include <arpa/inet.h> |
| 30 | |
| 31 | #include <errno.h> |
| 32 | #include <string.h> |
| 33 | |
Jacob Erlbeck | 4abc686 | 2015-12-08 15:14:05 +0100 | [diff] [blame] | 34 | #define LENGTH_TO_END 255 |
| 35 | /* |
| 36 | * \returns num extensions fields (num frames == offset) on success, |
| 37 | * -errno otherwise. |
| 38 | */ |
| 39 | static int parse_extensions_egprs(const uint8_t *data, unsigned int data_len, |
| 40 | unsigned int *offs, |
| 41 | bool is_last_block, |
| 42 | Decoding::RlcData *chunks, unsigned int chunks_size) |
| 43 | { |
| 44 | const struct rlc_li_field_egprs *li; |
| 45 | uint8_t e; |
| 46 | unsigned int num_chunks = 0; |
Jacob Erlbeck | 4abc686 | 2015-12-08 15:14:05 +0100 | [diff] [blame] | 47 | |
| 48 | e = 0; |
| 49 | while (!e) { |
| 50 | if (*offs > data_len) { |
| 51 | LOGP(DRLCMACUL, LOGL_NOTICE, "UL DATA LI extended, " |
| 52 | "but no more data\n"); |
| 53 | return -EINVAL; |
| 54 | } |
| 55 | |
| 56 | /* get new E */ |
| 57 | li = (struct rlc_li_field_egprs *)&data[*offs]; |
| 58 | e = li->e; |
| 59 | *offs += 1; |
| 60 | |
| 61 | if (!chunks) |
| 62 | continue; |
| 63 | |
| 64 | if (num_chunks == chunks_size) { |
| 65 | LOGP(DRLCMACUL, LOGL_NOTICE, "UL DATA LI extended, " |
| 66 | "but no more chunks possible\n"); |
| 67 | return -ENOSPC; |
| 68 | } |
| 69 | if (li->li == 0 && num_chunks == 0 && li->e == 0) { |
| 70 | /* TS 44.060, table 10.4.14a.1, row 2a */ |
| 71 | chunks[num_chunks].length = 0; |
| 72 | chunks[num_chunks].is_complete = true; |
| 73 | } else if (li->li == 0 && num_chunks == 0 && li->e == 1) { |
| 74 | /* TS 44.060, table 10.4.14a.1, row 4 */ |
Jacob Erlbeck | 4abc686 | 2015-12-08 15:14:05 +0100 | [diff] [blame] | 75 | chunks[num_chunks].length = LENGTH_TO_END; |
| 76 | chunks[num_chunks].is_complete = is_last_block; |
| 77 | } else if (li->li == 127 && li->e == 1) { |
| 78 | /* TS 44.060, table 10.4.14a.1, row 3 & 5 */ |
| 79 | /* only filling bytes left */ |
| 80 | break; |
| 81 | } else if (li->li > 0) { |
| 82 | /* TS 44.060, table 10.4.14a.1, row 1 & 2b */ |
| 83 | chunks[num_chunks].length = li->li; |
| 84 | chunks[num_chunks].is_complete = true; |
| 85 | } else { |
| 86 | LOGP(DRLCMACUL, LOGL_NOTICE, "UL DATA LI contains " |
| 87 | "invalid extension octet: LI=%d, E=%d, count=%d\n", |
| 88 | li->li, li->e, num_chunks); |
| 89 | return -EINVAL; |
| 90 | } |
| 91 | |
| 92 | num_chunks += 1; |
| 93 | |
| 94 | if (e == 1) { |
| 95 | /* There is space after the last chunk, add a final one */ |
| 96 | if (num_chunks == chunks_size) { |
| 97 | LOGP(DRLCMACUL, LOGL_NOTICE, |
| 98 | "UL DATA LI possibly extended, " |
| 99 | "but no more chunks possible\n"); |
| 100 | return -ENOSPC; |
| 101 | } |
| 102 | |
Jacob Erlbeck | 4abc686 | 2015-12-08 15:14:05 +0100 | [diff] [blame] | 103 | chunks[num_chunks].length = LENGTH_TO_END; |
| 104 | chunks[num_chunks].is_complete = is_last_block; |
Jacob Erlbeck | 4abc686 | 2015-12-08 15:14:05 +0100 | [diff] [blame] | 105 | num_chunks += 1; |
| 106 | } |
| 107 | } |
| 108 | |
| 109 | return num_chunks; |
| 110 | } |
| 111 | |
| 112 | static int parse_extensions_gprs(const uint8_t *data, unsigned int data_len, |
| 113 | unsigned int *offs, |
| 114 | bool is_last_block, |
| 115 | Decoding::RlcData *chunks, unsigned int chunks_size) |
| 116 | { |
| 117 | const struct rlc_li_field *li; |
| 118 | uint8_t m, e; |
| 119 | unsigned int num_chunks = 0; |
Jacob Erlbeck | 4abc686 | 2015-12-08 15:14:05 +0100 | [diff] [blame] | 120 | |
| 121 | e = 0; |
| 122 | while (!e) { |
| 123 | if (*offs > data_len) { |
| 124 | LOGP(DRLCMACUL, LOGL_NOTICE, "UL DATA LI extended, " |
| 125 | "but no more data\n"); |
| 126 | return -EINVAL; |
| 127 | } |
| 128 | |
| 129 | /* get new E */ |
| 130 | li = (const struct rlc_li_field *)&data[*offs]; |
| 131 | e = li->e; |
| 132 | m = li->m; |
| 133 | *offs += 1; |
| 134 | |
| 135 | if (li->li == 0) { |
| 136 | /* TS 44.060, 10.4.14, par 6 */ |
| 137 | e = 1; |
| 138 | m = 0; |
| 139 | } |
| 140 | |
| 141 | /* TS 44.060, table 10.4.13.1 */ |
| 142 | if (m == 0 && e == 0) { |
| 143 | LOGP(DRLCMACUL, LOGL_NOTICE, "UL DATA " |
| 144 | "ignored, because M='0' and E='0'.\n"); |
| 145 | return 0; |
| 146 | } |
| 147 | |
| 148 | if (!chunks) |
| 149 | continue; |
| 150 | |
| 151 | if (num_chunks == chunks_size) { |
| 152 | LOGP(DRLCMACUL, LOGL_NOTICE, "UL DATA LI extended, " |
| 153 | "but no more chunks possible\n"); |
| 154 | return -ENOSPC; |
| 155 | } |
| 156 | |
| 157 | if (li->li == 0) |
| 158 | /* e is 1 here */ |
Jacob Erlbeck | 4abc686 | 2015-12-08 15:14:05 +0100 | [diff] [blame] | 159 | chunks[num_chunks].length = LENGTH_TO_END; |
| 160 | else |
| 161 | chunks[num_chunks].length = li->li; |
| 162 | |
| 163 | chunks[num_chunks].is_complete = li->li || is_last_block; |
| 164 | |
Jacob Erlbeck | 4abc686 | 2015-12-08 15:14:05 +0100 | [diff] [blame] | 165 | num_chunks += 1; |
| 166 | |
| 167 | if (e == 1 && m == 1) { |
| 168 | if (num_chunks == chunks_size) { |
| 169 | LOGP(DRLCMACUL, LOGL_NOTICE, "UL DATA LI extended, " |
| 170 | "but no more chunks possible\n"); |
| 171 | return -ENOSPC; |
| 172 | } |
| 173 | /* TS 44.060, 10.4.13.1, row 4 */ |
Jacob Erlbeck | 4abc686 | 2015-12-08 15:14:05 +0100 | [diff] [blame] | 174 | chunks[num_chunks].length = LENGTH_TO_END; |
| 175 | chunks[num_chunks].is_complete = is_last_block; |
| 176 | num_chunks += 1; |
| 177 | } |
| 178 | } |
| 179 | |
| 180 | return num_chunks; |
| 181 | } |
| 182 | |
| 183 | int Decoding::rlc_data_from_ul_data( |
Jacob Erlbeck | f2ba4cb | 2016-01-07 18:59:28 +0100 | [diff] [blame] | 184 | const struct gprs_rlc_data_block_info *rdbi, GprsCodingScheme cs, |
Jacob Erlbeck | 4abc686 | 2015-12-08 15:14:05 +0100 | [diff] [blame] | 185 | const uint8_t *data, RlcData *chunks, unsigned int chunks_size, |
| 186 | uint32_t *tlli) |
| 187 | { |
| 188 | uint8_t e; |
| 189 | unsigned int data_len = rdbi->data_len; |
Jacob Erlbeck | ead5e47 | 2016-01-08 10:14:50 +0100 | [diff] [blame] | 190 | int num_chunks = 0, i; |
Jacob Erlbeck | 4abc686 | 2015-12-08 15:14:05 +0100 | [diff] [blame] | 191 | unsigned int offs = 0; |
| 192 | bool is_last_block = (rdbi->cv == 0); |
| 193 | |
| 194 | if (!chunks) |
| 195 | chunks_size = 0; |
| 196 | |
| 197 | e = rdbi->e; |
| 198 | if (e) { |
| 199 | if (chunks_size > 0) { |
| 200 | chunks[num_chunks].offset = offs; |
| 201 | chunks[num_chunks].length = LENGTH_TO_END; |
| 202 | chunks[num_chunks].is_complete = is_last_block; |
| 203 | num_chunks += 1; |
| 204 | } else if (chunks) { |
| 205 | LOGP(DRLCMACUL, LOGL_NOTICE, "No extension, " |
| 206 | "but no more chunks possible\n"); |
| 207 | return -ENOSPC; |
| 208 | } |
| 209 | } else if (cs.isEgprs()) { |
| 210 | /* if E is not set (LI follows), EGPRS */ |
| 211 | num_chunks = parse_extensions_egprs(data, data_len, &offs, |
| 212 | is_last_block, |
| 213 | chunks, chunks_size); |
| 214 | } else { |
| 215 | /* if E is not set (LI follows), GPRS */ |
| 216 | num_chunks = parse_extensions_gprs(data, data_len, &offs, |
| 217 | is_last_block, |
| 218 | chunks, chunks_size); |
| 219 | } |
| 220 | |
Jacob Erlbeck | ead5e47 | 2016-01-08 10:14:50 +0100 | [diff] [blame] | 221 | if (num_chunks < 0) |
| 222 | return num_chunks; |
| 223 | |
Jacob Erlbeck | 4abc686 | 2015-12-08 15:14:05 +0100 | [diff] [blame] | 224 | /* TLLI */ |
| 225 | if (rdbi->ti) { |
| 226 | uint32_t tlli_enc; |
| 227 | if (offs + 4 > data_len) { |
| 228 | LOGP(DRLCMACUL, LOGL_NOTICE, "UL DATA TLLI out of block " |
| 229 | "border\n"); |
| 230 | return -EINVAL; |
| 231 | } |
| 232 | |
| 233 | memcpy(&tlli_enc, data + offs, sizeof(tlli_enc)); |
| 234 | if (cs.isGprs()) |
| 235 | /* The TLLI is encoded in big endian for GPRS (see |
| 236 | * TS 44.060, figure 10.2.2.1, note) */ |
| 237 | *tlli = be32toh(tlli_enc); |
| 238 | else |
| 239 | /* The TLLI is encoded in little endian for EGPRS (see |
| 240 | * TS 44.060, figure 10.3a.2.1, note 2) */ |
| 241 | *tlli = le32toh(tlli_enc); |
| 242 | |
| 243 | offs += sizeof(tlli_enc); |
| 244 | } else { |
| 245 | *tlli = 0; |
| 246 | } |
| 247 | |
| 248 | /* PFI */ |
| 249 | if (rdbi->pi) { |
| 250 | LOGP(DRLCMACUL, LOGL_ERROR, "ERROR: PFI not supported, " |
| 251 | "please disable in SYSTEM INFORMATION\n"); |
| 252 | return -ENOTSUP; |
| 253 | |
| 254 | /* TODO: Skip all extensions with E=0 (see TS 44.060, 10.4.11 */ |
| 255 | } |
| 256 | |
Jacob Erlbeck | ead5e47 | 2016-01-08 10:14:50 +0100 | [diff] [blame] | 257 | if (chunks_size == 0) |
| 258 | return num_chunks; |
| 259 | |
Jacob Erlbeck | 4abc686 | 2015-12-08 15:14:05 +0100 | [diff] [blame] | 260 | /* LLC */ |
| 261 | for (i = 0; i < num_chunks; i++) { |
| 262 | chunks[i].offset = offs; |
| 263 | if (chunks[i].length == LENGTH_TO_END) { |
| 264 | if (offs == data_len) { |
| 265 | /* There is no place for an additional chunk, |
| 266 | * so drop it (this may happen with EGPRS since |
| 267 | * there is no M flag. */ |
| 268 | num_chunks -= 1; |
| 269 | break;; |
| 270 | } |
| 271 | chunks[i].length = data_len - offs; |
| 272 | } |
| 273 | offs += chunks[i].length; |
| 274 | if (offs > data_len) { |
| 275 | LOGP(DRLCMACUL, LOGL_NOTICE, "UL DATA out of block " |
| 276 | "border, chunk idx: %d, size: %d\n", |
| 277 | i, chunks[i].length); |
| 278 | return -EINVAL; |
| 279 | } |
| 280 | } |
| 281 | |
| 282 | return num_chunks; |
| 283 | } |
Holger Hans Peter Freyther | d11290b | 2013-10-26 17:32:04 +0200 | [diff] [blame] | 284 | |
Holger Hans Peter Freyther | fcbc702 | 2013-10-26 17:38:37 +0200 | [diff] [blame] | 285 | uint8_t Decoding::get_ms_class_by_capability(MS_Radio_Access_capability_t *cap) |
| 286 | { |
| 287 | int i; |
| 288 | |
| 289 | for (i = 0; i < cap->Count_MS_RA_capability_value; i++) { |
| 290 | if (!cap->MS_RA_capability_value[i].u.Content.Exist_Multislot_capability) |
| 291 | continue; |
| 292 | if (!cap->MS_RA_capability_value[i].u.Content.Multislot_capability.Exist_GPRS_multislot_class) |
| 293 | continue; |
| 294 | return cap->MS_RA_capability_value[i].u.Content.Multislot_capability.GPRS_multislot_class; |
| 295 | } |
| 296 | |
| 297 | return 0; |
| 298 | } |
| 299 | |
Jacob Erlbeck | c3c5804 | 2015-09-28 17:55:32 +0200 | [diff] [blame] | 300 | uint8_t Decoding::get_egprs_ms_class_by_capability(MS_Radio_Access_capability_t *cap) |
| 301 | { |
| 302 | int i; |
| 303 | |
| 304 | for (i = 0; i < cap->Count_MS_RA_capability_value; i++) { |
| 305 | if (!cap->MS_RA_capability_value[i].u.Content.Exist_Multislot_capability) |
| 306 | continue; |
| 307 | if (!cap->MS_RA_capability_value[i].u.Content.Multislot_capability.Exist_EGPRS_multislot_class) |
| 308 | continue; |
| 309 | return cap->MS_RA_capability_value[i].u.Content.Multislot_capability.EGPRS_multislot_class; |
| 310 | } |
| 311 | |
| 312 | return 0; |
| 313 | } |
| 314 | |
Holger Hans Peter Freyther | df6b4f5 | 2013-11-24 17:05:48 +0100 | [diff] [blame] | 315 | /** |
| 316 | * show_rbb needs to be an array with 65 elements |
Daniel Willmann | 5e94cd4 | 2013-12-11 20:11:16 +0100 | [diff] [blame] | 317 | * The index of the array is the bit position in the rbb |
| 318 | * (show_rbb[63] relates to BSN ssn-1) |
Holger Hans Peter Freyther | df6b4f5 | 2013-11-24 17:05:48 +0100 | [diff] [blame] | 319 | */ |
| 320 | void Decoding::extract_rbb(const uint8_t *rbb, char *show_rbb) |
| 321 | { |
Daniel Willmann | 5e94cd4 | 2013-12-11 20:11:16 +0100 | [diff] [blame] | 322 | for (int i = 0; i < 64; i++) { |
Holger Hans Peter Freyther | df6b4f5 | 2013-11-24 17:05:48 +0100 | [diff] [blame] | 323 | uint8_t bit; |
| 324 | |
Daniel Willmann | 5e94cd4 | 2013-12-11 20:11:16 +0100 | [diff] [blame] | 325 | bit = !!(rbb[i/8] & (1<<(7-i%8))); |
Daniel Willmann | 6f7cb2c | 2013-12-11 14:25:20 +0100 | [diff] [blame] | 326 | show_rbb[i] = bit ? 'R' : 'I'; |
Holger Hans Peter Freyther | df6b4f5 | 2013-11-24 17:05:48 +0100 | [diff] [blame] | 327 | } |
| 328 | |
| 329 | show_rbb[64] = '\0'; |
| 330 | } |
Jacob Erlbeck | 4abc686 | 2015-12-08 15:14:05 +0100 | [diff] [blame] | 331 | |
Jacob Erlbeck | f2f24b0 | 2016-02-05 13:16:24 +0100 | [diff] [blame] | 332 | void Decoding::extract_rbb(const struct bitvec *rbb, char *show_rbb) |
| 333 | { |
| 334 | unsigned int i; |
| 335 | for (i = 0; i < rbb->cur_bit; i++) { |
| 336 | uint8_t bit; |
| 337 | bit = bitvec_get_bit_pos(rbb, i); |
| 338 | show_rbb[i] = bit == 1 ? 'R' : 'I'; |
| 339 | } |
| 340 | |
| 341 | show_rbb[i] = '\0'; |
| 342 | } |
| 343 | |
Jacob Erlbeck | f2ba4cb | 2016-01-07 18:59:28 +0100 | [diff] [blame] | 344 | int Decoding::rlc_parse_ul_data_header(struct gprs_rlc_data_info *rlc, |
Jacob Erlbeck | 4abc686 | 2015-12-08 15:14:05 +0100 | [diff] [blame] | 345 | const uint8_t *data, GprsCodingScheme cs) |
| 346 | { |
| 347 | const struct gprs_rlc_ul_header_egprs_3 *egprs3; |
| 348 | const struct rlc_ul_header *gprs; |
| 349 | unsigned int e_ti_header; |
| 350 | unsigned int cur_bit = 0; |
| 351 | unsigned int data_len = 0; |
| 352 | |
| 353 | rlc->cs = cs; |
| 354 | |
| 355 | data_len = cs.maxDataBlockBytes(); |
| 356 | |
| 357 | switch(cs.headerTypeData()) { |
| 358 | case GprsCodingScheme::HEADER_GPRS_DATA: |
| 359 | gprs = static_cast<struct rlc_ul_header *> |
| 360 | ((void *)data); |
| 361 | rlc->r = gprs->r; |
| 362 | rlc->si = gprs->si; |
| 363 | rlc->tfi = gprs->tfi; |
| 364 | rlc->cps = 0; |
| 365 | rlc->rsb = 0; |
| 366 | |
| 367 | rlc->num_data_blocks = 1; |
| 368 | rlc->block_info[0].cv = gprs->cv; |
| 369 | rlc->block_info[0].pi = gprs->pi; |
| 370 | rlc->block_info[0].bsn = gprs->bsn; |
| 371 | rlc->block_info[0].e = gprs->e; |
| 372 | rlc->block_info[0].ti = gprs->ti; |
| 373 | rlc->block_info[0].spb = 0; |
| 374 | |
| 375 | cur_bit += 3 * 8; |
| 376 | |
| 377 | rlc->data_offs_bits[0] = cur_bit; |
| 378 | rlc->block_info[0].data_len = data_len; |
| 379 | cur_bit += data_len * 8; |
| 380 | |
| 381 | break; |
| 382 | case GprsCodingScheme::HEADER_EGPRS_DATA_TYPE_3: |
| 383 | egprs3 = static_cast<struct gprs_rlc_ul_header_egprs_3 *> |
| 384 | ((void *)data); |
| 385 | rlc->r = egprs3->r; |
| 386 | rlc->si = egprs3->si; |
| 387 | rlc->tfi = (egprs3->tfi_a << 0) | (egprs3->tfi_b << 2); |
| 388 | rlc->cps = (egprs3->cps_a << 0) | (egprs3->cps_b << 2); |
| 389 | rlc->rsb = egprs3->rsb; |
| 390 | |
| 391 | rlc->num_data_blocks = 1; |
| 392 | rlc->block_info[0].cv = egprs3->cv; |
| 393 | rlc->block_info[0].pi = egprs3->pi; |
| 394 | rlc->block_info[0].spb = egprs3->spb; |
| 395 | rlc->block_info[0].bsn = |
| 396 | (egprs3->bsn1_a << 0) | (egprs3->bsn1_b << 5); |
| 397 | |
| 398 | cur_bit += 3 * 8 + 7; |
| 399 | |
| 400 | e_ti_header = (data[3] + (data[4] << 8)) >> 7; |
| 401 | rlc->block_info[0].e = !!(e_ti_header & 0x01); |
| 402 | rlc->block_info[0].ti = !!(e_ti_header & 0x02); |
| 403 | cur_bit += 2; |
| 404 | |
| 405 | rlc->data_offs_bits[0] = cur_bit; |
| 406 | rlc->block_info[0].data_len = data_len; |
| 407 | cur_bit += data_len * 8; |
| 408 | |
| 409 | break; |
| 410 | |
| 411 | case GprsCodingScheme::HEADER_EGPRS_DATA_TYPE_1: |
| 412 | case GprsCodingScheme::HEADER_EGPRS_DATA_TYPE_2: |
| 413 | /* TODO: Support both header types */ |
| 414 | /* fall through */ |
| 415 | default: |
| 416 | LOGP(DRLCMACDL, LOGL_ERROR, |
| 417 | "Decoding of uplink %s data blocks not yet supported.\n", |
| 418 | cs.name()); |
| 419 | return -ENOTSUP; |
| 420 | }; |
| 421 | |
| 422 | return cur_bit; |
| 423 | } |
| 424 | |
| 425 | /** |
| 426 | * \brief Copy LSB bitstream RLC data block to byte aligned buffer. |
| 427 | * |
| 428 | * Note that the bitstream is encoded in LSB first order, so the two octets |
| 429 | * 654321xx xxxxxx87 contain the octet 87654321 starting at bit position 3 |
| 430 | * (LSB has bit position 1). This is a different order than the one used by |
| 431 | * CSN.1. |
| 432 | * |
| 433 | * \param data_block_idx The block index, 0..1 for header type 1, 0 otherwise |
| 434 | * \param src A pointer to the start of the RLC block (incl. the header) |
| 435 | * \param buffer A data area of a least the size of the RLC block |
| 436 | * \returns the number of bytes copied |
| 437 | */ |
| 438 | unsigned int Decoding::rlc_copy_to_aligned_buffer( |
Jacob Erlbeck | f2ba4cb | 2016-01-07 18:59:28 +0100 | [diff] [blame] | 439 | const struct gprs_rlc_data_info *rlc, |
Jacob Erlbeck | 4abc686 | 2015-12-08 15:14:05 +0100 | [diff] [blame] | 440 | unsigned int data_block_idx, |
| 441 | const uint8_t *src, uint8_t *buffer) |
| 442 | { |
| 443 | unsigned int hdr_bytes; |
| 444 | unsigned int extra_bits; |
| 445 | unsigned int i; |
| 446 | |
| 447 | uint8_t c, last_c; |
| 448 | uint8_t *dst; |
Jacob Erlbeck | f2ba4cb | 2016-01-07 18:59:28 +0100 | [diff] [blame] | 449 | const struct gprs_rlc_data_block_info *rdbi; |
Jacob Erlbeck | 4abc686 | 2015-12-08 15:14:05 +0100 | [diff] [blame] | 450 | |
| 451 | OSMO_ASSERT(data_block_idx < rlc->num_data_blocks); |
| 452 | rdbi = &rlc->block_info[data_block_idx]; |
| 453 | |
| 454 | hdr_bytes = rlc->data_offs_bits[data_block_idx] >> 3; |
| 455 | extra_bits = (rlc->data_offs_bits[data_block_idx] & 7); |
| 456 | |
| 457 | if (extra_bits == 0) { |
| 458 | /* It is aligned already */ |
| 459 | memmove(buffer, src + hdr_bytes, rdbi->data_len); |
| 460 | return rdbi->data_len; |
| 461 | } |
| 462 | |
| 463 | dst = buffer; |
| 464 | src = src + hdr_bytes; |
| 465 | last_c = *(src++); |
| 466 | |
| 467 | for (i = 0; i < rdbi->data_len; i++) { |
| 468 | c = src[i]; |
| 469 | *(dst++) = (last_c >> extra_bits) | (c << (8 - extra_bits)); |
| 470 | last_c = c; |
| 471 | } |
| 472 | |
| 473 | return rdbi->data_len; |
| 474 | } |
| 475 | |
| 476 | /** |
| 477 | * \brief Get a pointer to byte aligned RLC data. |
| 478 | * |
| 479 | * Since the RLC data may not be byte aligned to the RLC block data such that a |
| 480 | * single RLC data byte is spread over two RLC block bytes, this function |
| 481 | * eventually uses the provided buffer as data storage. |
| 482 | * |
| 483 | * \param src A pointer to the start of the RLC block (incl. the header) |
| 484 | * \param buffer A data area of a least the size of the RLC block |
| 485 | * \returns A pointer to the RLC data start within src if it is aligned, and |
| 486 | * buffer otherwise. |
| 487 | */ |
| 488 | const uint8_t *Decoding::rlc_get_data_aligned( |
Jacob Erlbeck | f2ba4cb | 2016-01-07 18:59:28 +0100 | [diff] [blame] | 489 | const struct gprs_rlc_data_info *rlc, |
Jacob Erlbeck | 4abc686 | 2015-12-08 15:14:05 +0100 | [diff] [blame] | 490 | unsigned int data_block_idx, |
| 491 | const uint8_t *src, uint8_t *buffer) |
| 492 | { |
| 493 | unsigned int hdr_bytes; |
| 494 | unsigned int extra_bits; |
| 495 | |
| 496 | OSMO_ASSERT(data_block_idx < ARRAY_SIZE(rlc->data_offs_bits)); |
| 497 | |
| 498 | hdr_bytes = rlc->data_offs_bits[data_block_idx] >> 3; |
| 499 | extra_bits = (rlc->data_offs_bits[data_block_idx] & 7); |
| 500 | |
| 501 | if (extra_bits == 0) |
| 502 | /* It is aligned already, return a pointer that refers to the |
| 503 | * original data. */ |
| 504 | return src + hdr_bytes; |
| 505 | |
| 506 | Decoding::rlc_copy_to_aligned_buffer(rlc, data_block_idx, src, buffer); |
| 507 | return buffer; |
| 508 | } |
Jacob Erlbeck | ae9c575 | 2016-01-13 13:55:44 +0100 | [diff] [blame] | 509 | |
| 510 | static int handle_final_ack(bitvec *bits, int *bsn_begin, int *bsn_end, |
| 511 | gprs_rlc_dl_window *window) |
| 512 | { |
| 513 | int num_blocks, i; |
| 514 | |
| 515 | num_blocks = window->mod_sns(window->v_s() - window->v_a()); |
| 516 | for (i = 0; i < num_blocks; i++) |
| 517 | bitvec_set_bit(bits, ONE); |
| 518 | |
| 519 | *bsn_begin = window->v_a(); |
| 520 | *bsn_end = window->mod_sns(*bsn_begin + num_blocks); |
| 521 | return num_blocks; |
| 522 | } |
| 523 | |
| 524 | int Decoding::decode_egprs_acknack_bits(const EGPRS_AckNack_Desc_t *desc, |
| 525 | bitvec *bits, int *bsn_begin, int *bsn_end, gprs_rlc_dl_window *window) |
| 526 | { |
| 527 | int urbb_len = desc->URBB_LENGTH; |
| 528 | int crbb_len = 0; |
| 529 | int num_blocks = 0; |
| 530 | struct bitvec urbb; |
| 531 | int i; |
| 532 | bool have_bitmap; |
| 533 | int implicitly_acked_blocks; |
| 534 | int ssn = desc->STARTING_SEQUENCE_NUMBER; |
Jacob Erlbeck | 2bef4db | 2016-01-20 14:33:11 +0100 | [diff] [blame] | 535 | int rc; |
Jacob Erlbeck | ae9c575 | 2016-01-13 13:55:44 +0100 | [diff] [blame] | 536 | |
| 537 | if (desc->FINAL_ACK_INDICATION) |
| 538 | return handle_final_ack(bits, bsn_begin, bsn_end, window); |
| 539 | |
| 540 | if (desc->Exist_CRBB) |
| 541 | crbb_len = desc->CRBB_LENGTH; |
| 542 | |
| 543 | have_bitmap = (urbb_len + crbb_len) > 0; |
| 544 | |
| 545 | /* |
| 546 | * bow & bitmap present: |
| 547 | * V(A)-> [ 11111...11111 0 SSN-> BBBBB...BBBBB ] (SSN+Nbits) .... V(S) |
| 548 | * bow & not bitmap present: |
| 549 | * V(A)-> [ 11111...11111 ] . SSN .... V(S) |
| 550 | * not bow & bitmap present: |
| 551 | * V(A)-> ... [ 0 SSN-> BBBBB...BBBBB ](SSN+N) .... V(S) |
| 552 | * not bow & not bitmap present: |
| 553 | * V(A)-> ... [] . SSN .... V(S) |
| 554 | */ |
| 555 | |
| 556 | if (desc->BEGINNING_OF_WINDOW) { |
| 557 | implicitly_acked_blocks = window->mod_sns(ssn - 1 - window->v_a()); |
| 558 | |
| 559 | for (i = 0; i < implicitly_acked_blocks; i++) |
| 560 | bitvec_set_bit(bits, ONE); |
| 561 | |
| 562 | num_blocks += implicitly_acked_blocks; |
| 563 | } |
| 564 | |
Jacob Erlbeck | 3fdcb2b | 2016-01-18 16:51:59 +0100 | [diff] [blame] | 565 | if (!have_bitmap) |
| 566 | goto aborted; |
Jacob Erlbeck | ae9c575 | 2016-01-13 13:55:44 +0100 | [diff] [blame] | 567 | |
Jacob Erlbeck | 3fdcb2b | 2016-01-18 16:51:59 +0100 | [diff] [blame] | 568 | /* next bit refers to V(Q) and thus is always zero (and not |
| 569 | * transmitted) */ |
| 570 | bitvec_set_bit(bits, ZERO); |
| 571 | num_blocks += 1; |
Jacob Erlbeck | ae9c575 | 2016-01-13 13:55:44 +0100 | [diff] [blame] | 572 | |
Jacob Erlbeck | 3fdcb2b | 2016-01-18 16:51:59 +0100 | [diff] [blame] | 573 | if (crbb_len > 0) { |
| 574 | int old_len = bits->cur_bit; |
Jacob Erlbeck | 3fdcb2b | 2016-01-18 16:51:59 +0100 | [diff] [blame] | 575 | struct bitvec crbb; |
Jacob Erlbeck | 3fdcb2b | 2016-01-18 16:51:59 +0100 | [diff] [blame] | 576 | |
| 577 | crbb.data = (uint8_t *)desc->CRBB; |
| 578 | crbb.data_len = sizeof(desc->CRBB); |
| 579 | crbb.cur_bit = desc->CRBB_LENGTH; |
| 580 | |
| 581 | rc = osmo_t4_decode(&crbb, desc->CRBB_STARTING_COLOR_CODE, |
| 582 | bits); |
| 583 | |
| 584 | if (rc < 0) { |
| 585 | LOGP(DRLCMACUL, LOGL_NOTICE, |
| 586 | "Failed to decode CRBB: " |
| 587 | "length %d, data '%s'\n", |
| 588 | desc->CRBB_LENGTH, |
| 589 | osmo_hexdump(crbb.data, crbb.data_len)); |
| 590 | /* We don't know the SSN offset for the URBB, |
| 591 | * return what we have so far and assume the |
| 592 | * bitmap has stopped here */ |
| 593 | goto aborted; |
Jacob Erlbeck | ae9c575 | 2016-01-13 13:55:44 +0100 | [diff] [blame] | 594 | } |
| 595 | |
Jacob Erlbeck | 3fdcb2b | 2016-01-18 16:51:59 +0100 | [diff] [blame] | 596 | LOGP(DRLCMACDL, LOGL_DEBUG, |
| 597 | "CRBB len: %d, decoded len: %d, cc: %d, crbb: '%s'\n", |
| 598 | desc->CRBB_LENGTH, bits->cur_bit - old_len, |
| 599 | desc->CRBB_STARTING_COLOR_CODE, |
| 600 | osmo_hexdump( |
| 601 | desc->CRBB, (desc->CRBB_LENGTH + 7)/8) |
| 602 | ); |
Jacob Erlbeck | ae9c575 | 2016-01-13 13:55:44 +0100 | [diff] [blame] | 603 | |
Jacob Erlbeck | 3fdcb2b | 2016-01-18 16:51:59 +0100 | [diff] [blame] | 604 | num_blocks += (bits->cur_bit - old_len); |
Jacob Erlbeck | ae9c575 | 2016-01-13 13:55:44 +0100 | [diff] [blame] | 605 | } |
| 606 | |
Jacob Erlbeck | 3fdcb2b | 2016-01-18 16:51:59 +0100 | [diff] [blame] | 607 | urbb.cur_bit = 0; |
| 608 | urbb.data = (uint8_t *)desc->URBB; |
| 609 | urbb.data_len = sizeof(desc->URBB); |
| 610 | |
| 611 | for (i = urbb_len; i > 0; i--) { |
| 612 | /* |
| 613 | * Set bit at the appropriate position (see 3GPP TS |
| 614 | * 44.060 12.3.1) |
| 615 | */ |
| 616 | int is_ack = bitvec_get_bit_pos(&urbb, i-1); |
| 617 | bitvec_set_bit(bits, is_ack == 1 ? ONE : ZERO); |
| 618 | } |
| 619 | num_blocks += urbb_len; |
| 620 | |
| 621 | aborted: |
Jacob Erlbeck | ae9c575 | 2016-01-13 13:55:44 +0100 | [diff] [blame] | 622 | *bsn_begin = window->v_a(); |
| 623 | *bsn_end = window->mod_sns(*bsn_begin + num_blocks); |
| 624 | |
| 625 | return num_blocks; |
| 626 | } |
Jacob Erlbeck | 192bf33 | 2016-02-05 13:10:29 +0100 | [diff] [blame] | 627 | |
| 628 | int Decoding::decode_gprs_acknack_bits(const Ack_Nack_Description_t *desc, |
| 629 | bitvec *bits, int *bsn_begin, int *bsn_end, gprs_rlc_dl_window *window) |
| 630 | { |
| 631 | int urbb_len = RLC_GPRS_WS; |
| 632 | int num_blocks; |
| 633 | struct bitvec urbb; |
| 634 | |
| 635 | if (desc->FINAL_ACK_INDICATION) |
| 636 | return handle_final_ack(bits, bsn_begin, bsn_end, window); |
| 637 | |
| 638 | *bsn_begin = window->v_a(); |
| 639 | *bsn_end = desc->STARTING_SEQUENCE_NUMBER; |
| 640 | |
| 641 | num_blocks = window->mod_sns(*bsn_end - *bsn_begin); |
| 642 | |
| 643 | if (num_blocks < 0 || num_blocks > urbb_len) { |
| 644 | *bsn_end = *bsn_begin; |
| 645 | LOGP(DRLCMACUL, LOGL_NOTICE, |
| 646 | "Invalid GPRS Ack/Nack window %d:%d (length %d)\n", |
| 647 | *bsn_begin, *bsn_end, num_blocks); |
| 648 | return -EINVAL; |
| 649 | } |
| 650 | |
| 651 | urbb.cur_bit = 0; |
| 652 | urbb.data = (uint8_t *)desc->RECEIVED_BLOCK_BITMAP; |
| 653 | urbb.data_len = sizeof(desc->RECEIVED_BLOCK_BITMAP); |
| 654 | |
| 655 | /* |
| 656 | * TS 44.060, 12.3: |
| 657 | * BSN = (SSN - bit_number) modulo 128, for bit_number = 1 to 64. |
| 658 | * The BSN values represented range from (SSN - 1) mod 128 to (SSN - 64) mod 128. |
| 659 | * |
| 660 | * We are only interested in the range from V(A) to SSN-1 which is |
| 661 | * num_blocks large. The RBB is laid out as |
| 662 | * [SSN-1] [SSN-2] ... [V(A)] ... [SSN-64] |
| 663 | * so we want to start with [V(A)] and go backwards until we reach |
| 664 | * [SSN-1] to get the needed BSNs in an increasing order. Note that |
| 665 | * the bit numbers are counted from the end of the buffer. |
| 666 | */ |
| 667 | for (int i = num_blocks; i > 0; i--) { |
| 668 | int is_ack = bitvec_get_bit_pos(&urbb, urbb_len - i); |
| 669 | bitvec_set_bit(bits, is_ack == 1 ? ONE : ZERO); |
| 670 | } |
| 671 | |
| 672 | return num_blocks; |
| 673 | } |