| /* tbf_ul_fsm.c |
| * |
| * Copyright (C) 2021-2022 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de> |
| * Author: Pau Espin Pedrol <pespin@sysmocom.de> |
| * |
| * 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. |
| */ |
| |
| #include <unistd.h> |
| |
| #include <talloc.h> |
| |
| #include <tbf_fsm.h> |
| #include <gprs_rlcmac.h> |
| #include <gprs_debug.h> |
| #include <gprs_ms.h> |
| #include <encoding.h> |
| #include <bts.h> |
| |
| #include <bts_pch_timer.h> |
| |
| #define X(s) (1 << (s)) |
| |
| static const struct osmo_tdef_state_timeout tbf_ul_fsm_timeouts[32] = { |
| [TBF_ST_NEW] = {}, |
| [TBF_ST_ASSIGN] = {}, |
| [TBF_ST_FLOW] = {}, |
| [TBF_ST_FINISHED] = {}, |
| [TBF_ST_RELEASING] = { .T = 3169 }, |
| }; |
| |
| /* Transition to a state, using the T timer defined in tbf_fsm_timeouts. |
| * The actual timeout value is in turn obtained from conn->T_defs. |
| * Assumes local variable fi exists. */ |
| #define tbf_ul_fsm_state_chg(fi, NEXT_STATE) \ |
| osmo_tdef_fsm_inst_state_chg(fi, NEXT_STATE, \ |
| tbf_ul_fsm_timeouts, \ |
| tbf_ms(((struct tbf_dl_fsm_ctx *)(fi->priv))->tbf)->bts->T_defs_bts, \ |
| -1) |
| |
| static void mod_ass_type(struct tbf_ul_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: |
| OSMO_ASSERT(0); |
| } |
| |
| LOGPTBFUL(ctx->ul_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 && prev_set) { |
| LOGPTBFUL(ctx->ul_tbf, LOGL_ERROR, |
| "Attempted to set ass. type %s which is already set\n", ch); |
| return; |
| } |
| |
| if (!set && !prev_set) |
| return; |
| |
| if (set) |
| ctx->state_flags |= (1 << t); |
| else |
| ctx->state_flags &= ~(1 << t); |
| } |
| |
| |
| static void st_new(struct osmo_fsm_inst *fi, uint32_t event, void *data) |
| { |
| struct tbf_ul_fsm_ctx *ctx = (struct tbf_ul_fsm_ctx *)fi->priv; |
| switch (event) { |
| case TBF_EV_ASSIGN_ADD_CCCH: |
| mod_ass_type(ctx, GPRS_RLCMAC_FLAG_CCCH, true); |
| tbf_ul_fsm_state_chg(fi, TBF_ST_FLOW); |
| ul_tbf_contention_resolution_start(ctx->ul_tbf); |
| break; |
| case TBF_EV_ASSIGN_ADD_PACCH: |
| mod_ass_type(ctx, GPRS_RLCMAC_FLAG_PACCH, true); |
| tbf_ul_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_ul_fsm_ctx *ctx = (struct tbf_ul_fsm_ctx *)fi->priv; |
| struct GprsMs *ms = tbf_ms(ctx->tbf); |
| 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 = 3168; |
| val = osmo_tdef_get(ms->bts->T_defs_bts, fi->T, OSMO_TDEF_MS, -1); |
| val *= 4; /* 4 PKT RES REQ retransmit */ |
| sec = val / 1000; |
| micro = (val % 1000) * 1000; |
| LOGPTBFUL(ctx->ul_tbf, LOGL_DEBUG, |
| "Starting timer T3168 [UL TBF Ass (PACCH)] with %u sec. %u microsec\n", |
| sec, micro); |
| osmo_timer_schedule(&fi->timer, sec, micro); |
| } |
| } |
| |
| static void st_assign(struct osmo_fsm_inst *fi, uint32_t event, void *data) |
| { |
| struct tbf_ul_fsm_ctx *ctx = (struct tbf_ul_fsm_ctx *)fi->priv; |
| |
| 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 */ |
| LOGPTBFUL(ctx->ul_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_ul_fsm_state_chg(fi, TBF_ST_FLOW); |
| break; |
| default: |
| OSMO_ASSERT(0); |
| } |
| } |
| |
| static void st_flow(struct osmo_fsm_inst *fi, uint32_t event, void *data) |
| { |
| struct tbf_ul_fsm_ctx *ctx = (struct tbf_ul_fsm_ctx *)fi->priv; |
| struct GprsMs *ms = tbf_ms(ctx->tbf); |
| struct gprs_rlcmac_dl_tbf *dl_tbf = NULL; |
| |
| switch (event) { |
| case TBF_EV_FIRST_UL_DATA_RECVD: |
| /* TS 44.060 7a.2.1.1: "The contention resolution is completed on |
| * the network side when the network receives an RLC data block that |
| * comprises the TLLI value that identifies the mobile station and the |
| * TFI value associated with the TBF." */ |
| bts_pch_timer_stop(ms->bts, ms); |
| /* We may still have some DL-TBF waiting for assignment in PCH, |
| * which clearly won't happen since the MS is on PDCH now. Get rid |
| * of it, it will be re-assigned on PACCH when contention |
| * resolution at the MS side is done (1st UL ACK/NACK sent) */ |
| if ((dl_tbf = ms_dl_tbf(ms))) { |
| /* Get rid of previous finished UL TBF before providing a new one */ |
| LOGPTBFDL(dl_tbf, LOGL_NOTICE, |
| "Got first UL data while DL-TBF pending, killing it\n"); |
| tbf_free(dl_tbf_as_tbf(dl_tbf)); |
| dl_tbf = NULL; |
| } |
| break; |
| case TBF_EV_CONTENTION_RESOLUTION_MS_SUCCESS: |
| ul_tbf_contention_resolution_success(tbf_as_ul_tbf(ctx->tbf)); |
| break; |
| case TBF_EV_LAST_UL_DATA_RECVD: |
| /* All data has been sent or received, change state to FINISHED */ |
| tbf_ul_fsm_state_chg(fi, TBF_ST_FINISHED); |
| break; |
| case TBF_EV_MAX_N3101: |
| tbf_ul_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_ul_fsm_ctx *ctx = (struct tbf_ul_fsm_ctx *)fi->priv; |
| struct GprsMs *ms; |
| bool new_ul_tbf_requested; |
| |
| switch (event) { |
| case TBF_EV_CONTENTION_RESOLUTION_MS_SUCCESS: |
| /* UL TBF: If MS only sends 1 RLCMAC UL block, it can be that we |
| * end up in FINISHED state before sending the first UL ACK/NACK */ |
| ul_tbf_contention_resolution_success(tbf_as_ul_tbf(ctx->tbf)); |
| break; |
| case TBF_EV_FINAL_UL_ACK_CONFIRMED: |
| new_ul_tbf_requested = (bool)data; |
| /* Ref the MS, otherwise it may be freed after ul_tbf is |
| * detached when sending event below. */ |
| ms = tbf_ms(ctx->tbf); |
| ms_ref(ms, __func__); |
| /* UL TBF ACKed our transmitted UL ACK/NACK with final Ack |
| * Indicator set to '1'. We can free the TBF right away, the MS |
| * also just released its TBF on its side. */ |
| LOGPTBFUL(tbf_as_ul_tbf(ctx->tbf), LOGL_DEBUG, "[UPLINK] END\n"); |
| tbf_free(ctx->tbf); |
| /* Here fi, ctx and ctx->tbf are already freed! */ |
| /* TS 44.060 9.3.3.3.2: There might be LLC packets waiting in |
| * the queue but the DL TBF assignment might have been delayed |
| * because there was no way to reach the MS (because ul_tbf was |
| * in packet-active mode with FINISHED state). If MS is going |
| * back to packet-idle mode then we can assign the DL TBF on PCH |
| * now. */ |
| if (!new_ul_tbf_requested && ms_need_dl_tbf(ms)) |
| ms_new_dl_tbf_assigned_on_pch(ms); |
| ms_unref(ms, __func__); |
| break; |
| case TBF_EV_MAX_N3103: |
| tbf_ul_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) |
| { |
| /* T3169 has been set entering this state: Wait for reuse of USF and |
| * TFI(s) after the MS uplink assignment for this TBF is invalid. Upon |
| * timeout, the timer_cb does tbf_free(). |
| */ |
| } |
| |
| static void st_releasing(struct osmo_fsm_inst *fi, uint32_t event, void *data) |
| { |
| switch (event) { |
| default: |
| OSMO_ASSERT(0); |
| } |
| } |
| |
| static int tbf_ul_fsm_timer_cb(struct osmo_fsm_inst *fi) |
| { |
| struct tbf_ul_fsm_ctx *ctx = (struct tbf_ul_fsm_ctx *)fi->priv; |
| switch (fi->T) { |
| case 3168: |
| LOGPTBFUL(ctx->ul_tbf, LOGL_NOTICE, "Releasing due to UL TBF PACCH assignment timeout\n"); |
| /* fall-through */ |
| case 3169: |
| tbf_free(ctx->tbf); |
| break; |
| default: |
| OSMO_ASSERT(0); |
| } |
| return 0; |
| } |
| |
| static struct osmo_fsm_state tbf_ul_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), |
| .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), |
| .out_state_mask = |
| X(TBF_ST_FLOW) | |
| X(TBF_ST_FINISHED), |
| .name = "ASSIGN", |
| .action = st_assign, |
| .onenter = st_assign_on_enter, |
| }, |
| [TBF_ST_FLOW] = { |
| .in_event_mask = |
| X(TBF_EV_FIRST_UL_DATA_RECVD) | |
| X(TBF_EV_CONTENTION_RESOLUTION_MS_SUCCESS) | |
| X(TBF_EV_LAST_UL_DATA_RECVD) | |
| X(TBF_EV_MAX_N3101), |
| .out_state_mask = |
| X(TBF_ST_ASSIGN) | |
| X(TBF_ST_FINISHED) | |
| X(TBF_ST_RELEASING), |
| .name = "FLOW", |
| .action = st_flow, |
| }, |
| [TBF_ST_FINISHED] = { |
| .in_event_mask = |
| X(TBF_EV_CONTENTION_RESOLUTION_MS_SUCCESS) | |
| X(TBF_EV_FINAL_UL_ACK_CONFIRMED) | |
| X(TBF_EV_MAX_N3103), |
| .out_state_mask = |
| X(TBF_ST_RELEASING), |
| .name = "FINISHED", |
| .action = st_finished, |
| }, |
| [TBF_ST_RELEASING] = { |
| .in_event_mask = 0, |
| .out_state_mask = 0, |
| .name = "RELEASING", |
| .action = st_releasing, |
| .onenter = st_releasing_on_enter, |
| }, |
| }; |
| |
| struct osmo_fsm tbf_ul_fsm = { |
| .name = "UL_TBF", |
| .states = tbf_ul_fsm_states, |
| .num_states = ARRAY_SIZE(tbf_ul_fsm_states), |
| .timer_cb = tbf_ul_fsm_timer_cb, |
| .log_subsys = DTBFUL, |
| .event_names = tbf_fsm_event_names, |
| }; |
| |
| static __attribute__((constructor)) void tbf_ul_fsm_init(void) |
| { |
| OSMO_ASSERT(osmo_fsm_register(&tbf_ul_fsm) == 0); |
| } |