Pau Espin Pedrol | 343c0ee | 2022-11-17 19:55:08 +0100 | [diff] [blame] | 1 | /* tbf_ul_fsm.c |
| 2 | * |
| 3 | * Copyright (C) 2021-2022 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de> |
| 4 | * Author: Pau Espin Pedrol <pespin@sysmocom.de> |
| 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 | |
| 17 | #include <unistd.h> |
| 18 | |
| 19 | #include <talloc.h> |
| 20 | |
| 21 | #include <tbf_fsm.h> |
| 22 | #include <gprs_rlcmac.h> |
| 23 | #include <gprs_debug.h> |
| 24 | #include <gprs_ms.h> |
| 25 | #include <encoding.h> |
| 26 | #include <bts.h> |
| 27 | |
| 28 | #include <bts_pch_timer.h> |
| 29 | |
| 30 | #define X(s) (1 << (s)) |
| 31 | |
Pau Espin Pedrol | 76ef666 | 2023-01-27 13:19:55 +0100 | [diff] [blame] | 32 | static const struct osmo_tdef_state_timeout tbf_ul_fsm_timeouts[32] = { |
Pau Espin Pedrol | 343c0ee | 2022-11-17 19:55:08 +0100 | [diff] [blame] | 33 | [TBF_ST_NEW] = {}, |
| 34 | [TBF_ST_ASSIGN] = { }, |
| 35 | [TBF_ST_FLOW] = { }, |
| 36 | [TBF_ST_FINISHED] = {}, |
| 37 | [TBF_ST_RELEASING] = {}, |
| 38 | }; |
| 39 | |
| 40 | /* Transition to a state, using the T timer defined in tbf_fsm_timeouts. |
| 41 | * The actual timeout value is in turn obtained from conn->T_defs. |
| 42 | * Assumes local variable fi exists. */ |
| 43 | #define tbf_ul_fsm_state_chg(fi, NEXT_STATE) \ |
| 44 | osmo_tdef_fsm_inst_state_chg(fi, NEXT_STATE, \ |
| 45 | tbf_ul_fsm_timeouts, \ |
| 46 | the_pcu->T_defs, \ |
| 47 | -1) |
| 48 | |
| 49 | static void mod_ass_type(struct tbf_ul_fsm_ctx *ctx, uint8_t t, bool set) |
| 50 | { |
| 51 | const char *ch = "UNKNOWN"; |
| 52 | bool prev_set = ctx->state_flags & (1 << t); |
| 53 | |
| 54 | switch (t) { |
| 55 | case GPRS_RLCMAC_FLAG_CCCH: |
| 56 | ch = "CCCH"; |
| 57 | break; |
| 58 | case GPRS_RLCMAC_FLAG_PACCH: |
| 59 | ch = "PACCH"; |
| 60 | break; |
| 61 | default: |
Pau Espin Pedrol | cdc762a | 2022-12-12 19:58:37 +0100 | [diff] [blame] | 62 | LOGPTBFUL(ctx->ul_tbf, LOGL_ERROR, |
| 63 | "attempted to %sset unexpected ass. type %d - FIXME!\n", |
| 64 | set ? "" : "un", t); |
Pau Espin Pedrol | 343c0ee | 2022-11-17 19:55:08 +0100 | [diff] [blame] | 65 | return; |
| 66 | } |
| 67 | |
| 68 | if (set && prev_set) |
Pau Espin Pedrol | cdc762a | 2022-12-12 19:58:37 +0100 | [diff] [blame] | 69 | LOGPTBFUL(ctx->ul_tbf, LOGL_ERROR, |
| 70 | "attempted to set ass. type %s which is already set.\n", ch); |
Pau Espin Pedrol | 343c0ee | 2022-11-17 19:55:08 +0100 | [diff] [blame] | 71 | else if (!set && !prev_set) |
| 72 | return; |
| 73 | |
Pau Espin Pedrol | cdc762a | 2022-12-12 19:58:37 +0100 | [diff] [blame] | 74 | LOGPTBFUL(ctx->ul_tbf, LOGL_INFO, "%sset ass. type %s [prev CCCH:%u, PACCH:%u]\n", |
| 75 | set ? "" : "un", ch, |
| 76 | !!(ctx->state_flags & (1 << GPRS_RLCMAC_FLAG_CCCH)), |
| 77 | !!(ctx->state_flags & (1 << GPRS_RLCMAC_FLAG_PACCH))); |
Pau Espin Pedrol | 343c0ee | 2022-11-17 19:55:08 +0100 | [diff] [blame] | 78 | |
| 79 | if (set) { |
| 80 | ctx->state_flags |= (1 << t); |
| 81 | } else { |
| 82 | ctx->state_flags &= GPRS_RLCMAC_FLAG_TO_MASK; /* keep to flags */ |
| 83 | ctx->state_flags &= ~(1 << t); |
| 84 | } |
| 85 | } |
| 86 | |
| 87 | |
| 88 | static void st_new(struct osmo_fsm_inst *fi, uint32_t event, void *data) |
| 89 | { |
| 90 | struct tbf_ul_fsm_ctx *ctx = (struct tbf_ul_fsm_ctx *)fi->priv; |
| 91 | switch (event) { |
| 92 | case TBF_EV_ASSIGN_ADD_CCCH: |
| 93 | mod_ass_type(ctx, GPRS_RLCMAC_FLAG_CCCH, true); |
| 94 | tbf_ul_fsm_state_chg(fi, TBF_ST_FLOW); |
Pau Espin Pedrol | cdc762a | 2022-12-12 19:58:37 +0100 | [diff] [blame] | 95 | ul_tbf_contention_resolution_start(ctx->ul_tbf); |
Pau Espin Pedrol | 343c0ee | 2022-11-17 19:55:08 +0100 | [diff] [blame] | 96 | break; |
| 97 | case TBF_EV_ASSIGN_ADD_PACCH: |
| 98 | mod_ass_type(ctx, GPRS_RLCMAC_FLAG_PACCH, true); |
| 99 | tbf_ul_fsm_state_chg(fi, TBF_ST_ASSIGN); |
| 100 | break; |
| 101 | default: |
| 102 | OSMO_ASSERT(0); |
| 103 | } |
| 104 | } |
| 105 | |
| 106 | static void st_assign_on_enter(struct osmo_fsm_inst *fi, uint32_t prev_state) |
| 107 | { |
| 108 | struct tbf_ul_fsm_ctx *ctx = (struct tbf_ul_fsm_ctx *)fi->priv; |
| 109 | unsigned long val; |
| 110 | unsigned int sec, micro; |
| 111 | |
| 112 | /* If assignment for this TBF is happening on PACCH, that means the |
| 113 | * actual Assignment procedure (tx/rx) is happening on another TBF (eg |
| 114 | * Ul TBF vs DL TBF). Hence we add a security timer here to free it in |
| 115 | * case the other TBF doesn't succeed in informing (assigning) the MS |
| 116 | * about this TBF, or simply because the scheduler takes too long to |
| 117 | * schedule it. This timer can probably be dropped once we make the |
| 118 | * other TBF always signal us assignment failure (we already get |
| 119 | * assignment success through TBF_EV_ASSIGN_ACK_PACCH) */ |
| 120 | if (ctx->state_flags & (1 << GPRS_RLCMAC_FLAG_PACCH)) { |
| 121 | fi->T = -2001; |
| 122 | val = osmo_tdef_get(the_pcu->T_defs, fi->T, OSMO_TDEF_MS, -1); |
| 123 | sec = val / 1000; |
| 124 | micro = (val % 1000) * 1000; |
Pau Espin Pedrol | cdc762a | 2022-12-12 19:58:37 +0100 | [diff] [blame] | 125 | LOGPTBFUL(ctx->ul_tbf, LOGL_DEBUG, |
| 126 | "Starting timer X2001 [assignment (PACCH)] with %u sec. %u microsec\n", |
| 127 | sec, micro); |
Pau Espin Pedrol | 343c0ee | 2022-11-17 19:55:08 +0100 | [diff] [blame] | 128 | osmo_timer_schedule(&fi->timer, sec, micro); |
| 129 | } |
| 130 | } |
| 131 | |
| 132 | static void st_assign(struct osmo_fsm_inst *fi, uint32_t event, void *data) |
| 133 | { |
| 134 | struct tbf_ul_fsm_ctx *ctx = (struct tbf_ul_fsm_ctx *)fi->priv; |
| 135 | |
| 136 | switch (event) { |
| 137 | case TBF_EV_ASSIGN_ADD_CCCH: |
| 138 | mod_ass_type(ctx, GPRS_RLCMAC_FLAG_CCCH, true); |
| 139 | break; |
| 140 | case TBF_EV_ASSIGN_ADD_PACCH: |
| 141 | mod_ass_type(ctx, GPRS_RLCMAC_FLAG_PACCH, true); |
| 142 | break; |
| 143 | case TBF_EV_ASSIGN_ACK_PACCH: |
| 144 | tbf_assign_control_ts(ctx->tbf); |
| 145 | if (ctx->state_flags & (1 << GPRS_RLCMAC_FLAG_CCCH)) { |
| 146 | /* We now know that the PACCH really existed */ |
Pau Espin Pedrol | cdc762a | 2022-12-12 19:58:37 +0100 | [diff] [blame] | 147 | LOGPTBFUL(ctx->ul_tbf, LOGL_INFO, |
| 148 | "The TBF has been confirmed on the PACCH, " |
| 149 | "changed type from CCCH to PACCH\n"); |
Pau Espin Pedrol | 343c0ee | 2022-11-17 19:55:08 +0100 | [diff] [blame] | 150 | mod_ass_type(ctx, GPRS_RLCMAC_FLAG_CCCH, false); |
| 151 | mod_ass_type(ctx, GPRS_RLCMAC_FLAG_PACCH, true); |
| 152 | } |
| 153 | tbf_ul_fsm_state_chg(fi, TBF_ST_FLOW); |
| 154 | break; |
| 155 | case TBF_EV_MAX_N3105: |
| 156 | /* We are going to release, so abort any Pkt Ul Ass pending to be scheduled: */ |
| 157 | osmo_fsm_inst_dispatch(tbf_ul_ass_fi(ctx->tbf), TBF_UL_ASS_EV_ABORT, NULL); |
| 158 | ctx->T_release = 3195; |
| 159 | tbf_ul_fsm_state_chg(fi, TBF_ST_RELEASING); |
| 160 | break; |
| 161 | default: |
| 162 | OSMO_ASSERT(0); |
| 163 | } |
| 164 | } |
| 165 | |
| 166 | static void st_flow(struct osmo_fsm_inst *fi, uint32_t event, void *data) |
| 167 | { |
| 168 | struct tbf_ul_fsm_ctx *ctx = (struct tbf_ul_fsm_ctx *)fi->priv; |
| 169 | struct GprsMs *ms = tbf_ms(ctx->tbf); |
| 170 | struct gprs_rlcmac_dl_tbf *dl_tbf = NULL; |
| 171 | |
| 172 | switch (event) { |
| 173 | case TBF_EV_FIRST_UL_DATA_RECVD: |
| 174 | OSMO_ASSERT(tbf_direction(ctx->tbf) == GPRS_RLCMAC_UL_TBF); |
| 175 | /* TS 44.060 7a.2.1.1: "The contention resolution is completed on |
| 176 | * the network side when the network receives an RLC data block that |
| 177 | * comprises the TLLI value that identifies the mobile station and the |
| 178 | * TFI value associated with the TBF." */ |
| 179 | bts_pch_timer_stop(ms->bts, ms); |
| 180 | /* We may still have some DL-TBF waiting for assignment in PCH, |
| 181 | * which clearly won't happen since the MS is on PDCH now. Get rid |
| 182 | * of it, it will be re-assigned on PACCH when contention |
| 183 | * resolution at the MS side is done (1st UL ACK/NACK sent) */ |
| 184 | if ((dl_tbf = ms_dl_tbf(ms))) { |
| 185 | /* Get rid of previous finished UL TBF before providing a new one */ |
| 186 | LOGPTBFDL(dl_tbf, LOGL_NOTICE, |
| 187 | "Got first UL data while DL-TBF pending, killing it\n"); |
| 188 | tbf_free(dl_tbf_as_tbf(dl_tbf)); |
| 189 | dl_tbf = NULL; |
| 190 | } |
| 191 | break; |
| 192 | case TBF_EV_CONTENTION_RESOLUTION_MS_SUCCESS: |
| 193 | ul_tbf_contention_resolution_success(tbf_as_ul_tbf(ctx->tbf)); |
| 194 | break; |
| 195 | case TBF_EV_LAST_UL_DATA_RECVD: |
| 196 | /* All data has been sent or received, change state to FINISHED */ |
| 197 | tbf_ul_fsm_state_chg(fi, TBF_ST_FINISHED); |
| 198 | break; |
| 199 | case TBF_EV_MAX_N3101: |
| 200 | ctx->T_release = 3169; |
| 201 | tbf_ul_fsm_state_chg(fi, TBF_ST_RELEASING); |
| 202 | break; |
| 203 | case TBF_EV_MAX_N3105: |
| 204 | ctx->T_release = 3195; |
| 205 | tbf_ul_fsm_state_chg(fi, TBF_ST_RELEASING); |
| 206 | break; |
| 207 | default: |
| 208 | OSMO_ASSERT(0); |
| 209 | } |
| 210 | } |
| 211 | |
| 212 | static void st_finished(struct osmo_fsm_inst *fi, uint32_t event, void *data) |
| 213 | { |
| 214 | struct tbf_ul_fsm_ctx *ctx = (struct tbf_ul_fsm_ctx *)fi->priv; |
| 215 | struct GprsMs *ms; |
| 216 | bool new_ul_tbf_requested; |
| 217 | |
| 218 | switch (event) { |
| 219 | case TBF_EV_CONTENTION_RESOLUTION_MS_SUCCESS: |
| 220 | /* UL TBF: If MS only sends 1 RLCMAC UL block, it can be that we |
| 221 | * end up in FINISHED state before sending the first UL ACK/NACK */ |
| 222 | ul_tbf_contention_resolution_success(tbf_as_ul_tbf(ctx->tbf)); |
| 223 | break; |
| 224 | case TBF_EV_FINAL_UL_ACK_CONFIRMED: |
| 225 | OSMO_ASSERT(tbf_direction(ctx->tbf) == GPRS_RLCMAC_UL_TBF); |
| 226 | new_ul_tbf_requested = (bool)data; |
| 227 | /* Ref the MS, otherwise it may be freed after ul_tbf is |
| 228 | * detached when sending event below. */ |
| 229 | ms = tbf_ms(ctx->tbf); |
| 230 | ms_ref(ms); |
| 231 | /* UL TBF ACKed our transmitted UL ACK/NACK with final Ack |
| 232 | * Indicator set to '1'. We can free the TBF right away, the MS |
| 233 | * also just released its TBF on its side. */ |
| 234 | LOGPTBFUL(tbf_as_ul_tbf(ctx->tbf), LOGL_DEBUG, "[UPLINK] END\n"); |
| 235 | tbf_free(ctx->tbf); |
| 236 | /* Here fi, ctx and ctx->tbf are already freed! */ |
| 237 | /* TS 44.060 9.3.3.3.2: There might be LLC packets waiting in |
| 238 | * the queue but the DL TBF assignment might have been delayed |
| 239 | * because there was no way to reach the MS (because ul_tbf was |
| 240 | * in packet-active mode with FINISHED state). If MS is going |
| 241 | * back to packet-idle mode then we can assign the DL TBF on PCH |
| 242 | * now. */ |
| 243 | if (!new_ul_tbf_requested && ms_need_dl_tbf(ms)) |
| 244 | ms_new_dl_tbf_assigned_on_pch(ms); |
| 245 | ms_unref(ms); |
| 246 | break; |
| 247 | case TBF_EV_MAX_N3103: |
| 248 | ctx->T_release = 3169; |
| 249 | tbf_ul_fsm_state_chg(fi, TBF_ST_RELEASING); |
| 250 | break; |
| 251 | case TBF_EV_MAX_N3105: |
| 252 | ctx->T_release = 3195; |
| 253 | tbf_ul_fsm_state_chg(fi, TBF_ST_RELEASING); |
| 254 | break; |
| 255 | default: |
| 256 | OSMO_ASSERT(0); |
| 257 | } |
| 258 | } |
| 259 | |
| 260 | static void st_releasing_on_enter(struct osmo_fsm_inst *fi, uint32_t prev_state) |
| 261 | { |
| 262 | struct tbf_ul_fsm_ctx *ctx = (struct tbf_ul_fsm_ctx *)fi->priv; |
| 263 | unsigned long val; |
| 264 | |
| 265 | if (!ctx->T_release) |
| 266 | return; |
| 267 | |
| 268 | /* In general we should end up here with an assigned timer in ctx->T_release. Possible values are: |
| 269 | * T3195: Wait for reuse of TFI(s) when there is no response from the MS |
| 270 | * (radio failure or cell change) for this TBF/MBMS radio bearer. |
| 271 | * T3169: Wait for reuse of USF and TFI(s) after the MS uplink assignment for this TBF is invalid. |
| 272 | */ |
| 273 | val = osmo_tdef_get(tbf_ms(ctx->tbf)->bts->T_defs_bts, ctx->T_release, OSMO_TDEF_S, -1); |
| 274 | fi->T = ctx->T_release; |
Pau Espin Pedrol | cdc762a | 2022-12-12 19:58:37 +0100 | [diff] [blame] | 275 | LOGPTBFUL(ctx->ul_tbf, LOGL_DEBUG, "starting timer T%u with %lu sec. %u microsec\n", |
| 276 | ctx->T_release, val, 0); |
Pau Espin Pedrol | 343c0ee | 2022-11-17 19:55:08 +0100 | [diff] [blame] | 277 | osmo_timer_schedule(&fi->timer, val, 0); |
| 278 | } |
| 279 | |
| 280 | static void st_releasing(struct osmo_fsm_inst *fi, uint32_t event, void *data) |
| 281 | { |
Pau Espin Pedrol | 02d4b2a | 2023-03-07 17:57:05 +0100 | [diff] [blame] | 282 | switch (event) { |
| 283 | case TBF_EV_MAX_N3105: |
| 284 | /* This may be received here if the TBF had several polls |
| 285 | * allocated concurrently and several failed each increasing N3105 |
| 286 | * over MAX_N3015. We are already releasing, ignore.*/ |
| 287 | break; |
| 288 | default: |
| 289 | OSMO_ASSERT(0); |
| 290 | } |
Pau Espin Pedrol | 343c0ee | 2022-11-17 19:55:08 +0100 | [diff] [blame] | 291 | } |
| 292 | |
| 293 | static int tbf_ul_fsm_timer_cb(struct osmo_fsm_inst *fi) |
| 294 | { |
| 295 | struct tbf_ul_fsm_ctx *ctx = (struct tbf_ul_fsm_ctx *)fi->priv; |
| 296 | switch (fi->T) { |
| 297 | case -2001: |
Pau Espin Pedrol | cdc762a | 2022-12-12 19:58:37 +0100 | [diff] [blame] | 298 | LOGPTBFUL(ctx->ul_tbf, LOGL_NOTICE, "releasing due to PACCH assignment timeout.\n"); |
Pau Espin Pedrol | 343c0ee | 2022-11-17 19:55:08 +0100 | [diff] [blame] | 299 | /* fall-through */ |
| 300 | case 3169: |
| 301 | case 3195: |
| 302 | tbf_free(ctx->tbf); |
| 303 | break; |
| 304 | default: |
| 305 | OSMO_ASSERT(0); |
| 306 | } |
| 307 | return 0; |
| 308 | } |
| 309 | |
| 310 | static struct osmo_fsm_state tbf_ul_fsm_states[] = { |
| 311 | [TBF_ST_NEW] = { |
| 312 | .in_event_mask = |
| 313 | X(TBF_EV_ASSIGN_ADD_CCCH) | |
| 314 | X(TBF_EV_ASSIGN_ADD_PACCH), |
| 315 | .out_state_mask = |
| 316 | X(TBF_ST_ASSIGN) | |
| 317 | X(TBF_ST_FLOW) | |
| 318 | X(TBF_ST_RELEASING), |
| 319 | .name = "NEW", |
| 320 | .action = st_new, |
| 321 | }, |
| 322 | [TBF_ST_ASSIGN] = { |
| 323 | .in_event_mask = |
| 324 | X(TBF_EV_ASSIGN_ADD_CCCH) | |
| 325 | X(TBF_EV_ASSIGN_ADD_PACCH) | |
| 326 | X(TBF_EV_ASSIGN_ACK_PACCH) | |
| 327 | X(TBF_EV_MAX_N3105), |
| 328 | .out_state_mask = |
| 329 | X(TBF_ST_FLOW) | |
| 330 | X(TBF_ST_FINISHED) | |
| 331 | X(TBF_ST_RELEASING), |
| 332 | .name = "ASSIGN", |
| 333 | .action = st_assign, |
| 334 | .onenter = st_assign_on_enter, |
| 335 | }, |
| 336 | [TBF_ST_FLOW] = { |
| 337 | .in_event_mask = |
| 338 | X(TBF_EV_FIRST_UL_DATA_RECVD) | |
| 339 | X(TBF_EV_CONTENTION_RESOLUTION_MS_SUCCESS) | |
| 340 | X(TBF_EV_LAST_UL_DATA_RECVD) | |
| 341 | X(TBF_EV_MAX_N3101) | |
| 342 | X(TBF_EV_MAX_N3105), |
| 343 | .out_state_mask = |
| 344 | X(TBF_ST_ASSIGN) | |
| 345 | X(TBF_ST_FINISHED) | |
| 346 | X(TBF_ST_RELEASING), |
| 347 | .name = "FLOW", |
| 348 | .action = st_flow, |
| 349 | }, |
| 350 | [TBF_ST_FINISHED] = { |
| 351 | .in_event_mask = |
| 352 | X(TBF_EV_CONTENTION_RESOLUTION_MS_SUCCESS) | |
| 353 | X(TBF_EV_FINAL_UL_ACK_CONFIRMED) | |
| 354 | X(TBF_EV_MAX_N3103) | |
| 355 | X(TBF_EV_MAX_N3105), |
| 356 | .out_state_mask = |
| 357 | X(TBF_ST_RELEASING), |
| 358 | .name = "FINISHED", |
| 359 | .action = st_finished, |
| 360 | }, |
| 361 | [TBF_ST_RELEASING] = { |
Pau Espin Pedrol | 02d4b2a | 2023-03-07 17:57:05 +0100 | [diff] [blame] | 362 | .in_event_mask = |
| 363 | X(TBF_EV_MAX_N3105), |
Pau Espin Pedrol | 343c0ee | 2022-11-17 19:55:08 +0100 | [diff] [blame] | 364 | .out_state_mask = |
| 365 | 0, |
| 366 | .name = "RELEASING", |
| 367 | .action = st_releasing, |
| 368 | .onenter = st_releasing_on_enter, |
| 369 | }, |
| 370 | }; |
| 371 | |
| 372 | struct osmo_fsm tbf_ul_fsm = { |
| 373 | .name = "UL_TBF", |
| 374 | .states = tbf_ul_fsm_states, |
| 375 | .num_states = ARRAY_SIZE(tbf_ul_fsm_states), |
| 376 | .timer_cb = tbf_ul_fsm_timer_cb, |
| 377 | .log_subsys = DTBFUL, |
| 378 | .event_names = tbf_fsm_event_names, |
| 379 | }; |
| 380 | |
| 381 | static __attribute__((constructor)) void tbf_ul_fsm_init(void) |
| 382 | { |
| 383 | OSMO_ASSERT(osmo_fsm_register(&tbf_ul_fsm) == 0); |
| 384 | } |