/* tbf_fsm.c * * Copyright (C) 2021 by sysmocom - s.f.m.c. GmbH * Author: Pau Espin Pedrol * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include #include #include #include #include #include #include #include #define X(s) (1 << (s)) const struct osmo_tdef_state_timeout tbf_fsm_timeouts[32] = { [TBF_ST_NEW] = {}, [TBF_ST_ASSIGN] = { }, [TBF_ST_FLOW] = { }, [TBF_ST_FINISHED] = {}, [TBF_ST_WAIT_RELEASE] = {}, [TBF_ST_RELEASING] = {}, }; const struct value_string tbf_fsm_event_names[] = { { TBF_EV_ASSIGN_ADD_CCCH, "ASSIGN_ADD_CCCH" }, { TBF_EV_ASSIGN_ADD_PACCH, "ASSIGN_ADD_PACCH" }, { TBF_EV_ASSIGN_ACK_PACCH, "ASSIGN_ACK_PACCH" }, { TBF_EV_ASSIGN_READY_CCCH, "ASSIGN_READY_CCCH" }, { TBF_EV_ASSIGN_PCUIF_CNF, "ASSIGN_PCUIF_CNF" }, { TBF_EV_DL_ACKNACK_MISS, "DL_ACKNACK_MISS" }, { TBF_EV_LAST_DL_DATA_SENT, "LAST_DL_DATA_SENT" }, { TBF_EV_LAST_UL_DATA_RECVD, "LAST_UL_DATA_RECVD" }, { TBF_EV_FINAL_ACK_RECVD, "FINAL_ACK_RECVD" }, { TBF_EV_FINAL_UL_ACK_CONFIRMED, "FINAL_UL_ACK_CONFIRMED" }, { TBF_EV_MAX_N3101 , "MAX_N3101" }, { TBF_EV_MAX_N3103 , "MAX_N3103" }, { TBF_EV_MAX_N3105 , "MAX_N3105" }, { 0, NULL } }; static void mod_ass_type(struct tbf_fsm_ctx *ctx, uint8_t t, bool set) { const char *ch = "UNKNOWN"; bool prev_set = ctx->state_flags & (1 << t); switch (t) { case GPRS_RLCMAC_FLAG_CCCH: ch = "CCCH"; break; case GPRS_RLCMAC_FLAG_PACCH: ch = "PACCH"; break; default: LOGPTBF(ctx->tbf, LOGL_ERROR, "attempted to %sset unexpected ass. type %d - FIXME!\n", set ? "" : "un", t); return; } if (set && prev_set) { LOGPTBF(ctx->tbf, LOGL_ERROR, "attempted to set ass. type %s which is already set.\n", ch); } else if (!set && !prev_set) { return; } LOGPTBF(ctx->tbf, LOGL_INFO, "%sset ass. type %s [prev CCCH:%u, PACCH:%u]\n", set ? "" : "un", ch, !!(ctx->state_flags & (1 << GPRS_RLCMAC_FLAG_CCCH)), !!(ctx->state_flags & (1 << GPRS_RLCMAC_FLAG_PACCH))); if (set) { ctx->state_flags |= (1 << t); } else { ctx->state_flags &= GPRS_RLCMAC_FLAG_TO_MASK; /* keep to flags */ ctx->state_flags &= ~(1 << t); } } static void st_new(struct osmo_fsm_inst *fi, uint32_t event, void *data) { struct tbf_fsm_ctx *ctx = (struct tbf_fsm_ctx *)fi->priv; switch (event) { case TBF_EV_ASSIGN_ADD_CCCH: mod_ass_type(ctx, GPRS_RLCMAC_FLAG_CCCH, true); tbf_fsm_state_chg(fi, tbf_direction(ctx->tbf) == GPRS_RLCMAC_DL_TBF ? TBF_ST_ASSIGN : TBF_ST_FLOW); break; case TBF_EV_ASSIGN_ADD_PACCH: mod_ass_type(ctx, GPRS_RLCMAC_FLAG_PACCH, true); tbf_fsm_state_chg(fi, TBF_ST_ASSIGN); break; default: OSMO_ASSERT(0); } } static void st_assign_on_enter(struct osmo_fsm_inst *fi, uint32_t prev_state) { struct tbf_fsm_ctx *ctx = (struct tbf_fsm_ctx *)fi->priv; unsigned long val; unsigned int sec, micro; /* If assignment for this TBF is happening on PACCH, that means the * actual Assignment procedure (tx/rx) is happening on another TBF (eg * Ul TBF vs DL TBF). Hence we add a security timer here to free it in * case the other TBF doesn't succeed in informing (assigning) the MS * about this TBF, or simply because the scheduler takes too long to * schedule it. This timer can probably be dropped once we make the * other TBF always signal us assignment failure (we already get * assignment success through TBF_EV_ASSIGN_ACK_PACCH) */ if (ctx->state_flags & (1 << GPRS_RLCMAC_FLAG_PACCH)) { fi->T = -2001; val = osmo_tdef_get(the_pcu->T_defs, fi->T, OSMO_TDEF_MS, -1); sec = val / 1000; micro = (val % 1000) * 1000; LOGPTBF(ctx->tbf, LOGL_DEBUG, "Starting timer X2001 [assignment (PACCH)] with %u sec. %u microsec\n", sec, micro); osmo_timer_schedule(&fi->timer, sec, micro); } else if (tbf_direction(ctx->tbf) == GPRS_RLCMAC_DL_TBF) { /* GPRS_RLCMAC_FLAG_CCCH is set, so here we submitted an DL Ass through PCUIF on CCCH */ } } static void st_assign(struct osmo_fsm_inst *fi, uint32_t event, void *data) { struct tbf_fsm_ctx *ctx = (struct tbf_fsm_ctx *)fi->priv; unsigned long val; unsigned int sec, micro; switch (event) { case TBF_EV_ASSIGN_ADD_CCCH: mod_ass_type(ctx, GPRS_RLCMAC_FLAG_CCCH, true); break; case TBF_EV_ASSIGN_ADD_PACCH: mod_ass_type(ctx, GPRS_RLCMAC_FLAG_PACCH, true); break; case TBF_EV_ASSIGN_ACK_PACCH: tbf_assign_control_ts(ctx->tbf); if (ctx->state_flags & (1 << GPRS_RLCMAC_FLAG_CCCH)) { /* We now know that the PACCH really existed */ LOGPTBF(ctx->tbf, LOGL_INFO, "The TBF has been confirmed on the PACCH, " "changed type from CCCH to PACCH\n"); mod_ass_type(ctx, GPRS_RLCMAC_FLAG_CCCH, false); mod_ass_type(ctx, GPRS_RLCMAC_FLAG_PACCH, true); } tbf_fsm_state_chg(fi, TBF_ST_FLOW); break; case TBF_EV_ASSIGN_PCUIF_CNF: /* BTS informs us it sent Imm Ass for DL TBF over CCCH. We now * have to wait for X2002 to trigger (meaning MS is already * listening on PDCH) in order to move to FLOW state and start * transmitting data to it. When X2002 triggers (see cb timer * end of the file) it will send TBF_EV_ASSIGN_READY_CCCH back * to us here. */ OSMO_ASSERT(tbf_direction(ctx->tbf) == GPRS_RLCMAC_DL_TBF); fi->T = -2002; val = osmo_tdef_get(the_pcu->T_defs, fi->T, OSMO_TDEF_MS, -1); sec = val / 1000; micro = (val % 1000) * 1000; LOGPTBF(ctx->tbf, LOGL_DEBUG, "Starting timer X2002 [assignment (AGCH)] with %u sec. %u microsec\n", sec, micro); osmo_timer_schedule(&fi->timer, sec, micro); break; case TBF_EV_ASSIGN_READY_CCCH: /* change state to FLOW, so scheduler will start transmission */ tbf_fsm_state_chg(fi, TBF_ST_FLOW); break; case TBF_EV_MAX_N3105: /* We are going to release, so abort any Pkt Ul Ass pending to be scheduled: */ osmo_fsm_inst_dispatch(tbf_ul_ass_fi(ctx->tbf), TBF_UL_ASS_EV_ABORT, NULL); ctx->T_release = 3195; tbf_fsm_state_chg(fi, TBF_ST_RELEASING); break; default: OSMO_ASSERT(0); } } static void st_flow(struct osmo_fsm_inst *fi, uint32_t event, void *data) { struct tbf_fsm_ctx *ctx = (struct tbf_fsm_ctx *)fi->priv; switch (event) { case TBF_EV_DL_ACKNACK_MISS: /* DL TBF: we missed a DL ACK/NACK. If we started assignment * over CCCH and never received any DL ACK/NACK yet, it means we * don't even know if the MS successfuly received the Imm Ass on * CCCH and hence is listening on PDCH. Let's better refrain * from continuing and start assignment on CCCH again */ if ((ctx->state_flags & (1 << GPRS_RLCMAC_FLAG_CCCH)) && !(ctx->state_flags & (1 << GPRS_RLCMAC_FLAG_DL_ACK))) { struct GprsMs *ms = tbf_ms(ctx->tbf); const char *imsi = ms_imsi(ms); uint16_t pgroup; LOGPTBF(ctx->tbf, LOGL_DEBUG, "Re-send downlink assignment on PCH (IMSI=%s)\n", imsi); tbf_fsm_state_chg(fi, TBF_ST_ASSIGN); /* send immediate assignment */ if ((pgroup = imsi2paging_group(imsi)) > 999) LOGPTBF(ctx->tbf, LOGL_ERROR, "IMSI to paging group failed! (%s)\n", imsi); bts_snd_dl_ass(ms->bts, ctx->tbf, pgroup); } break; case TBF_EV_LAST_DL_DATA_SENT: case TBF_EV_LAST_UL_DATA_RECVD: /* All data has been sent or received, change state to FINISHED */ tbf_fsm_state_chg(fi, TBF_ST_FINISHED); break; case TBF_EV_FINAL_ACK_RECVD: /* We received Final Ack (DL ACK/NACK) from MS. move to WAIT_RELEASE, we wait there for release or re-use the TBF in case we receive more DL data to tx */ tbf_fsm_state_chg(fi, TBF_ST_WAIT_RELEASE); break; case TBF_EV_MAX_N3101: ctx->T_release = 3169; tbf_fsm_state_chg(fi, TBF_ST_RELEASING); break; case TBF_EV_MAX_N3105: ctx->T_release = 3195; tbf_fsm_state_chg(fi, TBF_ST_RELEASING); break; default: OSMO_ASSERT(0); } } static void st_finished(struct osmo_fsm_inst *fi, uint32_t event, void *data) { struct tbf_fsm_ctx *ctx = (struct tbf_fsm_ctx *)fi->priv; switch (event) { case TBF_EV_DL_ACKNACK_MISS: break; case TBF_EV_FINAL_ACK_RECVD: /* We received Final Ack (DL ACK/NACK) from MS. move to WAIT_RELEASE, we wait there for release or re-use the TBF in case we receive more DL data to tx */ tbf_fsm_state_chg(fi, TBF_ST_WAIT_RELEASE); break; case TBF_EV_FINAL_UL_ACK_CONFIRMED: /* UL TBF ACKed our transmitted UL ACK/NACK with final Ack * Indicator set to '1' t. We can free the TBF right away. */ tbf_free(ctx->tbf); break; case TBF_EV_MAX_N3103: ctx->T_release = 3169; tbf_fsm_state_chg(fi, TBF_ST_RELEASING); break; case TBF_EV_MAX_N3105: ctx->T_release = 3195; tbf_fsm_state_chg(fi, TBF_ST_RELEASING); break; default: OSMO_ASSERT(0); } } static void st_wait_release_on_enter(struct osmo_fsm_inst *fi, uint32_t prev_state) { struct tbf_fsm_ctx *ctx = (struct tbf_fsm_ctx *)fi->priv; unsigned long val_s, val_ms, val_us; OSMO_ASSERT(tbf_direction(ctx->tbf) == GPRS_RLCMAC_DL_TBF); fi->T = 3193; val_ms = osmo_tdef_get(tbf_ms(ctx->tbf)->bts->T_defs_bts, fi->T, OSMO_TDEF_MS, -1); val_s = val_ms / 1000; val_us = (val_ms % 1000) * 1000; LOGPTBF(ctx->tbf, LOGL_DEBUG, "starting timer T%u with %lu sec. %lu microsec\n", fi->T, val_s, val_us); osmo_timer_schedule(&fi->timer, val_s, val_us); mod_ass_type(ctx, GPRS_RLCMAC_FLAG_CCCH, false); } static void st_wait_release(struct osmo_fsm_inst *fi, uint32_t event, void *data) { struct tbf_fsm_ctx *ctx = (struct tbf_fsm_ctx *)fi->priv; switch (event) { case TBF_EV_FINAL_ACK_RECVD: /* ignore, duplicate ACK, we already know about since we are in WAIT_RELEASE */ break; case TBF_EV_MAX_N3101: ctx->T_release = 3169; tbf_fsm_state_chg(fi, TBF_ST_RELEASING); break; case TBF_EV_MAX_N3105: ctx->T_release = 3195; tbf_fsm_state_chg(fi, TBF_ST_RELEASING); break; default: OSMO_ASSERT(0); } } static void st_releasing_on_enter(struct osmo_fsm_inst *fi, uint32_t prev_state) { struct tbf_fsm_ctx *ctx = (struct tbf_fsm_ctx *)fi->priv; unsigned long val; if (!ctx->T_release) return; /* In general we should end up here with an assigned timer in ctx->T_release. Possible values are: * T3195: Wait for reuse of TFI(s) when there is no response from the MS * (radio failure or cell change) for this TBF/MBMS radio bearer. * T3169: Wait for reuse of USF and TFI(s) after the MS uplink assignment for this TBF is invalid. */ val = osmo_tdef_get(tbf_ms(ctx->tbf)->bts->T_defs_bts, ctx->T_release, OSMO_TDEF_S, -1); fi->T = ctx->T_release; LOGPTBF(ctx->tbf, LOGL_DEBUG, "starting timer T%u with %lu sec. %u microsec\n", ctx->T_release, val, 0); osmo_timer_schedule(&fi->timer, val, 0); } static void st_releasing(struct osmo_fsm_inst *fi, uint32_t event, void *data) { switch (event) { case TBF_EV_DL_ACKNACK_MISS: /* Ignore, we don't care about missed DL ACK/NACK poll timeouts * anymore, we are already releasing the TBF */ break; default: OSMO_ASSERT(0); } } static void handle_timeout_X2002(struct tbf_fsm_ctx *ctx) { struct gprs_rlcmac_dl_tbf *dl_tbf = as_dl_tbf(ctx->tbf); /* X2002 is used only for DL TBF */ OSMO_ASSERT(dl_tbf); if (ctx->fi->state == TBF_ST_ASSIGN) { tbf_assign_control_ts(ctx->tbf); if (!tbf_can_upgrade_to_multislot(ctx->tbf)) { /* change state to FLOW, so scheduler * will start transmission */ osmo_fsm_inst_dispatch(ctx->fi, TBF_EV_ASSIGN_READY_CCCH, NULL); return; } /* This tbf can be upgraded to use multiple DL * timeslots and now that there is already one * slot assigned send another DL assignment via * PDCH. */ /* keep to flags */ ctx->state_flags &= GPRS_RLCMAC_FLAG_TO_MASK; tbf_update(ctx->tbf); tbf_dl_trigger_ass(dl_tbf, ctx->tbf); } else LOGPTBF(ctx->tbf, LOGL_NOTICE, "Continue flow after IMM.ASS confirm\n"); } static int tbf_fsm_timer_cb(struct osmo_fsm_inst *fi) { struct tbf_fsm_ctx *ctx = (struct tbf_fsm_ctx *)fi->priv; switch (fi->T) { case -2002: handle_timeout_X2002(ctx); break; case -2001: LOGPTBF(ctx->tbf, LOGL_NOTICE, "releasing due to PACCH assignment timeout.\n"); /* fall-through */ case 3169: case 3193: case 3195: tbf_free(ctx->tbf); break; default: OSMO_ASSERT(0); } return 0; } static struct osmo_fsm_state tbf_fsm_states[] = { [TBF_ST_NEW] = { .in_event_mask = X(TBF_EV_ASSIGN_ADD_CCCH) | X(TBF_EV_ASSIGN_ADD_PACCH), .out_state_mask = X(TBF_ST_ASSIGN) | X(TBF_ST_FLOW) | X(TBF_ST_RELEASING), .name = "NEW", .action = st_new, }, [TBF_ST_ASSIGN] = { .in_event_mask = X(TBF_EV_ASSIGN_ADD_CCCH) | X(TBF_EV_ASSIGN_ADD_PACCH) | X(TBF_EV_ASSIGN_ACK_PACCH) | X(TBF_EV_ASSIGN_PCUIF_CNF) | X(TBF_EV_ASSIGN_READY_CCCH) | X(TBF_EV_MAX_N3105), .out_state_mask = X(TBF_ST_FLOW) | X(TBF_ST_FINISHED) | X(TBF_ST_RELEASING), .name = "ASSIGN", .action = st_assign, .onenter = st_assign_on_enter, }, [TBF_ST_FLOW] = { .in_event_mask = X(TBF_EV_DL_ACKNACK_MISS) | X(TBF_EV_LAST_DL_DATA_SENT) | X(TBF_EV_LAST_UL_DATA_RECVD) | X(TBF_EV_FINAL_ACK_RECVD) | X(TBF_EV_MAX_N3101) | X(TBF_EV_MAX_N3105), .out_state_mask = X(TBF_ST_ASSIGN) | X(TBF_ST_FINISHED) | X(TBF_ST_WAIT_RELEASE) | X(TBF_ST_RELEASING), .name = "FLOW", .action = st_flow, }, [TBF_ST_FINISHED] = { .in_event_mask = X(TBF_EV_DL_ACKNACK_MISS) | X(TBF_EV_FINAL_ACK_RECVD) | X(TBF_EV_FINAL_UL_ACK_CONFIRMED) | X(TBF_EV_MAX_N3103) | X(TBF_EV_MAX_N3105), .out_state_mask = X(TBF_ST_WAIT_RELEASE) | X(TBF_ST_RELEASING), .name = "FINISHED", .action = st_finished, }, [TBF_ST_WAIT_RELEASE] = { .in_event_mask = X(TBF_EV_FINAL_ACK_RECVD) | X(TBF_EV_MAX_N3101) | X(TBF_EV_MAX_N3105), .out_state_mask = X(TBF_ST_RELEASING), .name = "WAIT_RELEASE", .action = st_wait_release, .onenter = st_wait_release_on_enter, }, [TBF_ST_RELEASING] = { .in_event_mask = X(TBF_EV_DL_ACKNACK_MISS), .out_state_mask = 0, .name = "RELEASING", .action = st_releasing, .onenter = st_releasing_on_enter, }, }; struct osmo_fsm tbf_fsm = { .name = "TBF", .states = tbf_fsm_states, .num_states = ARRAY_SIZE(tbf_fsm_states), .timer_cb = tbf_fsm_timer_cb, .log_subsys = DTBF, .event_names = tbf_fsm_event_names, }; static __attribute__((constructor)) void tbf_fsm_init(void) { OSMO_ASSERT(osmo_fsm_register(&tbf_fsm) == 0); }