Pau Espin Pedrol | ea8dbdd | 2021-07-29 18:39:16 +0200 | [diff] [blame] | 1 | /* tbf_ul_ack_fsm.c |
| 2 | * |
| 3 | * Copyright (C) 2021 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. |
Pau Espin Pedrol | ea8dbdd | 2021-07-29 18:39:16 +0200 | [diff] [blame] | 15 | */ |
| 16 | |
| 17 | #include <unistd.h> |
| 18 | |
| 19 | #include <talloc.h> |
| 20 | |
| 21 | #include <osmocom/core/bitvec.h> |
| 22 | |
| 23 | #include <tbf_ul_ack_fsm.h> |
| 24 | #include <gprs_rlcmac.h> |
| 25 | #include <gprs_debug.h> |
| 26 | #include <gprs_ms.h> |
| 27 | #include <encoding.h> |
| 28 | #include <bts.h> |
| 29 | #include <tbf.h> |
| 30 | #include <tbf_ul.h> |
| 31 | |
| 32 | #include <tbf_ul_ack_fsm.h> |
| 33 | |
| 34 | #define X(s) (1 << (s)) |
| 35 | |
| 36 | const struct osmo_tdef_state_timeout tbf_ul_ack_fsm_timeouts[32] = { |
| 37 | [TBF_UL_ACK_ST_NONE] = {}, |
| 38 | [TBF_UL_ACK_ST_SCHED_UL_ACK] = {}, |
| 39 | [TBF_UL_ACK_ST_WAIT_ACK] = {}, |
| 40 | }; |
| 41 | |
| 42 | const struct value_string tbf_ul_ack_fsm_event_names[] = { |
| 43 | { TBF_UL_ACK_EV_SCHED_ACK, "SCHED_ACK" }, |
| 44 | { TBF_UL_ACK_EV_CREATE_RLCMAC_MSG, "CREATE_RLCMAC_MSG" }, |
| 45 | { TBF_UL_ACK_EV_RX_CTRL_ACK, "RX_CTRL_ACK" }, |
| 46 | { TBF_UL_ACK_EV_POLL_TIMEOUT, "POLL_TIMEOUT" }, |
| 47 | { 0, NULL } |
| 48 | }; |
| 49 | |
| 50 | static struct msgb *create_ul_ack_nack(const struct tbf_ul_ack_fsm_ctx *ctx, |
| 51 | const struct tbf_ul_ack_ev_create_rlcmac_msg_ctx *d, |
| 52 | bool final) |
| 53 | { |
| 54 | struct msgb *msg; |
| 55 | int rc; |
| 56 | unsigned int rrbp = 0; |
| 57 | uint32_t new_poll_fn = 0; |
| 58 | struct gprs_rlcmac_tbf *tbf = (struct gprs_rlcmac_tbf *)ctx->tbf; |
| 59 | struct GprsMs *ms = tbf_ms(tbf); |
| 60 | |
| 61 | if (final) { |
| 62 | rc = tbf_check_polling(tbf, d->fn, d->ts, &new_poll_fn, &rrbp); |
| 63 | if (rc < 0) |
| 64 | return NULL; |
| 65 | } |
| 66 | |
| 67 | msg = msgb_alloc(23, "rlcmac_ul_ack"); |
| 68 | if (!msg) |
| 69 | return NULL; |
| 70 | struct bitvec *ack_vec = bitvec_alloc(23, tbf); |
| 71 | if (!ack_vec) { |
| 72 | msgb_free(msg); |
| 73 | return NULL; |
| 74 | } |
| 75 | bitvec_unhex(ack_vec, DUMMY_VEC); |
| 76 | write_packet_uplink_ack(ack_vec, ctx->tbf, final, rrbp); |
| 77 | bitvec_pack(ack_vec, msgb_put(msg, 23)); |
| 78 | bitvec_free(ack_vec); |
| 79 | |
| 80 | /* TS 44.060 7a.2.1.1: "The contention resolution is completed on |
| 81 | * the network side when the network receives an RLC data block that |
| 82 | * comprises the TLLI value that identifies the mobile station and the |
| 83 | * TFI value associated with the TBF." |
| 84 | * However, it's handier for us to mark contention resolution success |
| 85 | * here since according to spec upon rx UL ACK is the time at which MS |
| 86 | * realizes contention resolution succeeds. */ |
| 87 | if (ms_tlli(ms) != GSM_RESERVED_TMSI) |
| 88 | ul_tbf_contention_resolution_success(ctx->tbf); |
| 89 | |
Pau Espin Pedrol | a161bf4 | 2021-07-30 13:42:06 +0200 | [diff] [blame] | 90 | if (final) { |
Pau Espin Pedrol | ea8dbdd | 2021-07-29 18:39:16 +0200 | [diff] [blame] | 91 | tbf_set_polling(tbf, new_poll_fn, d->ts, PDCH_ULC_POLL_UL_ACK); |
Pau Espin Pedrol | a161bf4 | 2021-07-30 13:42:06 +0200 | [diff] [blame] | 92 | LOGPTBFUL(tbf, LOGL_DEBUG, |
| 93 | "Scheduled UL Acknowledgement polling on PACCH (FN=%d, TS=%d)\n", |
| 94 | new_poll_fn, d->ts); |
| 95 | } |
Pau Espin Pedrol | ea8dbdd | 2021-07-29 18:39:16 +0200 | [diff] [blame] | 96 | |
| 97 | return msg; |
| 98 | } |
| 99 | |
| 100 | static void st_none(struct osmo_fsm_inst *fi, uint32_t event, void *data) |
| 101 | { |
| 102 | switch (event) { |
| 103 | case TBF_UL_ACK_EV_SCHED_ACK: |
| 104 | tbf_ul_ack_fsm_state_chg(fi, TBF_UL_ACK_ST_SCHED_UL_ACK); |
| 105 | break; |
| 106 | default: |
| 107 | OSMO_ASSERT(0); |
| 108 | } |
| 109 | } |
| 110 | |
| 111 | static void st_sched_ul_ack(struct osmo_fsm_inst *fi, uint32_t event, void *data) |
| 112 | { |
| 113 | struct tbf_ul_ack_fsm_ctx *ctx = (struct tbf_ul_ack_fsm_ctx *)fi->priv; |
| 114 | struct gprs_rlcmac_tbf *tbf = (struct gprs_rlcmac_tbf *)ctx->tbf; |
| 115 | struct tbf_ul_ack_ev_create_rlcmac_msg_ctx *data_ctx; |
| 116 | bool final; |
| 117 | |
| 118 | switch (event) { |
| 119 | case TBF_UL_ACK_EV_SCHED_ACK: |
| 120 | LOGPTBFUL(tbf, LOGL_DEBUG, |
| 121 | "Sending Ack/Nack already scheduled, no need to re-schedule\n"); |
| 122 | break; |
| 123 | case TBF_UL_ACK_EV_CREATE_RLCMAC_MSG: |
| 124 | data_ctx = (struct tbf_ul_ack_ev_create_rlcmac_msg_ctx *)data; |
| 125 | final = tbf_state(tbf) == TBF_ST_FINISHED; |
| 126 | data_ctx->msg = create_ul_ack_nack(ctx, data_ctx, final); |
| 127 | if (!data_ctx->msg) |
| 128 | return; |
| 129 | if (final) /* poll set */ |
| 130 | tbf_ul_ack_fsm_state_chg(fi, TBF_UL_ACK_ST_WAIT_ACK); |
| 131 | else |
| 132 | tbf_ul_ack_fsm_state_chg(fi, TBF_UL_ACK_ST_NONE); |
| 133 | break; |
| 134 | default: |
| 135 | OSMO_ASSERT(0); |
| 136 | } |
| 137 | } |
| 138 | |
| 139 | static void st_wait_ctrl_ack(struct osmo_fsm_inst *fi, uint32_t event, void *data) |
| 140 | { |
| 141 | struct tbf_ul_ack_fsm_ctx *ctx = (struct tbf_ul_ack_fsm_ctx *)fi->priv; |
| 142 | struct gprs_rlcmac_tbf *tbf = (struct gprs_rlcmac_tbf *)ctx->tbf; |
| 143 | |
| 144 | switch (event) { |
| 145 | case TBF_UL_ACK_EV_SCHED_ACK: |
| 146 | /* ignore, we are in the middle of waiting for a response */ |
| 147 | break; |
| 148 | case TBF_UL_ACK_EV_RX_CTRL_ACK: |
| 149 | tbf_ul_ack_fsm_state_chg(fi, TBF_UL_ACK_ST_NONE); |
| 150 | break; |
| 151 | case TBF_UL_ACK_EV_POLL_TIMEOUT: |
| 152 | LOGPTBF(tbf, LOGL_NOTICE, |
| 153 | "Timeout for polling PACKET CONTROL ACK for PACKET UPLINK ACK: %s\n", |
| 154 | tbf_rlcmac_diag(tbf)); |
| 155 | /* Reschedule Ul Ack/NAck */ |
| 156 | tbf_ul_ack_fsm_state_chg(fi, TBF_UL_ACK_ST_SCHED_UL_ACK); |
| 157 | break; |
| 158 | default: |
| 159 | OSMO_ASSERT(0); |
| 160 | } |
| 161 | } |
| 162 | |
| 163 | static int tbf_ul_ack_fsm_timer_cb(struct osmo_fsm_inst *fi) |
| 164 | { |
| 165 | switch (fi->T) { |
| 166 | default: |
| 167 | OSMO_ASSERT(0); |
| 168 | } |
| 169 | return 0; |
| 170 | } |
| 171 | |
| 172 | static struct osmo_fsm_state tbf_ul_ack_fsm_states[] = { |
| 173 | [TBF_UL_ACK_ST_NONE] = { |
| 174 | .in_event_mask = |
| 175 | X(TBF_UL_ACK_EV_SCHED_ACK), |
| 176 | .out_state_mask = |
| 177 | X(TBF_UL_ACK_ST_SCHED_UL_ACK), |
| 178 | .name = "NONE", |
| 179 | .action = st_none, |
| 180 | }, |
| 181 | [TBF_UL_ACK_ST_SCHED_UL_ACK] = { |
| 182 | .in_event_mask = |
| 183 | X(TBF_UL_ACK_EV_SCHED_ACK) | |
| 184 | X(TBF_UL_ACK_EV_CREATE_RLCMAC_MSG), |
| 185 | .out_state_mask = |
| 186 | X(TBF_UL_ACK_ST_NONE) | |
| 187 | X(TBF_UL_ACK_ST_WAIT_ACK), |
| 188 | .name = "SCHED_UL_ACK", |
| 189 | .action = st_sched_ul_ack, |
| 190 | }, |
| 191 | [TBF_UL_ACK_ST_WAIT_ACK] = { |
| 192 | .in_event_mask = |
| 193 | X(TBF_UL_ACK_EV_SCHED_ACK) | |
| 194 | X(TBF_UL_ACK_EV_RX_CTRL_ACK) | |
| 195 | X(TBF_UL_ACK_EV_POLL_TIMEOUT), |
| 196 | .out_state_mask = |
| 197 | X(TBF_UL_ACK_ST_NONE) | |
| 198 | X(TBF_UL_ACK_ST_SCHED_UL_ACK), |
| 199 | .name = "WAIT_ACK", |
| 200 | .action = st_wait_ctrl_ack, |
| 201 | }, |
| 202 | }; |
| 203 | |
| 204 | struct osmo_fsm tbf_ul_ack_fsm = { |
| 205 | .name = "UL_ACK_TBF", |
| 206 | .states = tbf_ul_ack_fsm_states, |
| 207 | .num_states = ARRAY_SIZE(tbf_ul_ack_fsm_states), |
| 208 | .timer_cb = tbf_ul_ack_fsm_timer_cb, |
| 209 | .log_subsys = DTBFUL, |
| 210 | .event_names = tbf_ul_ack_fsm_event_names, |
| 211 | }; |
| 212 | |
| 213 | static __attribute__((constructor)) void tbf_ul_ack_fsm_init(void) |
| 214 | { |
| 215 | OSMO_ASSERT(osmo_fsm_register(&tbf_ul_ack_fsm) == 0); |
| 216 | } |
| 217 | |
| 218 | |
| 219 | struct msgb *tbf_ul_ack_create_rlcmac_msg(const struct gprs_rlcmac_tbf *tbf, uint32_t fn, uint8_t ts) |
| 220 | { |
| 221 | int rc; |
| 222 | struct tbf_ul_ack_ev_create_rlcmac_msg_ctx data_ctx = { |
| 223 | .fn = fn, |
| 224 | .ts = ts, |
| 225 | .msg = NULL, |
| 226 | }; |
| 227 | OSMO_ASSERT(tbf_direction(tbf) == GPRS_RLCMAC_UL_TBF); |
| 228 | |
| 229 | rc = osmo_fsm_inst_dispatch(tbf_ul_ack_fi((const struct gprs_rlcmac_ul_tbf *)tbf), TBF_UL_ACK_EV_CREATE_RLCMAC_MSG, &data_ctx); |
| 230 | if (rc != 0 || !data_ctx.msg) |
| 231 | return NULL; |
| 232 | return data_ctx.msg; |
| 233 | } |
| 234 | |
| 235 | bool tbf_ul_ack_rts(const struct gprs_rlcmac_tbf *tbf) |
| 236 | { |
| 237 | struct osmo_fsm_inst *fi = tbf_ul_ack_fi((const struct gprs_rlcmac_ul_tbf *)tbf); |
| 238 | return fi->state == TBF_UL_ACK_ST_SCHED_UL_ACK; |
| 239 | } |
| 240 | |
| 241 | /* Did we already send the Final ACK and we are waiting for its confirmation (CTRL ACK) ? */ |
| 242 | bool tbf_ul_ack_waiting_cnf_final_ack(const struct gprs_rlcmac_tbf* tbf) |
| 243 | { |
| 244 | OSMO_ASSERT(tbf_direction(tbf) == GPRS_RLCMAC_UL_TBF); |
| 245 | struct osmo_fsm_inst *fi = tbf_ul_ack_fi((const struct gprs_rlcmac_ul_tbf *)tbf); |
| 246 | return fi->state == TBF_UL_ACK_ST_WAIT_ACK; |
| 247 | } |
| 248 | |
| 249 | bool tbf_ul_ack_exp_ctrl_ack(const struct gprs_rlcmac_tbf *tbf, uint32_t fn, uint8_t ts) |
| 250 | { |
| 251 | struct osmo_fsm_inst *fi = tbf_ul_ack_fi((const struct gprs_rlcmac_ul_tbf *)tbf); |
| 252 | return fi->state == TBF_UL_ACK_ST_WAIT_ACK; |
| 253 | /* FIXME: validate FN and TS match: && ctx->poll_fn = fn && ctx->poll_ts == ts */ |
| 254 | } |