274 lines
7.8 KiB
C
274 lines
7.8 KiB
C
/* tbf_ul_ack_fsm.c
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*
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* Copyright (C) 2021 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
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* Author: Pau Espin Pedrol <pespin@sysmocom.de>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <unistd.h>
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#include <talloc.h>
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#include <osmocom/core/bitvec.h>
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#include <tbf_ul_ack_fsm.h>
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#include <gprs_rlcmac.h>
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#include <gprs_debug.h>
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#include <gprs_ms.h>
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#include <encoding.h>
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#include <bts.h>
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#include <tbf.h>
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#include <tbf_ul.h>
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#include <tbf_ul_ack_fsm.h>
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#define X(s) (1 << (s))
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static const struct osmo_tdef_state_timeout tbf_ul_ack_fsm_timeouts[32] = {
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[TBF_UL_ACK_ST_NONE] = {},
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[TBF_UL_ACK_ST_SCHED_UL_ACK] = {},
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[TBF_UL_ACK_ST_WAIT_ACK] = {},
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};
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static const struct value_string tbf_ul_ack_fsm_event_names[] = {
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{ TBF_UL_ACK_EV_SCHED_ACK, "SCHED_ACK" },
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{ TBF_UL_ACK_EV_CREATE_RLCMAC_MSG, "CREATE_RLCMAC_MSG" },
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{ TBF_UL_ACK_EV_RX_CTRL_ACK, "RX_CTRL_ACK" },
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{ TBF_UL_ACK_EV_POLL_TIMEOUT, "POLL_TIMEOUT" },
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{ 0, NULL }
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};
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/* Transition to a state, using the T timer defined in tbf_ul_ack_fsm_timeouts.
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* The actual timeout value is in turn obtained from conn->T_defs.
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* Assumes local variable fi exists. */
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#define tbf_ul_ack_fsm_state_chg(fi, NEXT_STATE) \
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osmo_tdef_fsm_inst_state_chg(fi, NEXT_STATE, \
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tbf_ul_ack_fsm_timeouts, \
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the_pcu->T_defs, \
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-1)
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static struct msgb *create_ul_ack_nack(const struct tbf_ul_ack_fsm_ctx *ctx,
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const struct tbf_ul_ack_ev_create_rlcmac_msg_ctx *d,
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bool final)
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{
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struct msgb *msg;
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int rc;
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unsigned int rrbp = 0;
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uint32_t new_poll_fn = 0;
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struct gprs_rlcmac_ul_tbf *tbf = ctx->tbf;
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struct GprsMs *ms = tbf_ms(ul_tbf_as_tbf(tbf));
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if (final) {
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rc = tbf_check_polling(ul_tbf_as_tbf(tbf), d->pdch, d->fn, &new_poll_fn, &rrbp);
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if (rc < 0)
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return NULL;
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}
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msg = msgb_alloc(23, "rlcmac_ul_ack");
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if (!msg)
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return NULL;
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struct bitvec *ack_vec = bitvec_alloc(23, tbf);
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if (!ack_vec) {
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msgb_free(msg);
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return NULL;
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}
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bitvec_unhex(ack_vec, DUMMY_VEC);
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write_packet_uplink_ack(ack_vec, ctx->tbf, final, rrbp);
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bitvec_pack(ack_vec, msgb_put(msg, 23));
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bitvec_free(ack_vec);
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/* TS 44.060 7a.2.1.1: "The contention resolution is completed on
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* the network side when the network receives an RLC data block that
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* comprises the TLLI value that identifies the mobile station and the
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* TFI value associated with the TBF." (see TBF_EV_FIRST_UL_DATA_RECVD).
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*
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* However, it's handier for us to mark contention resolution success here
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* since upon rx UL ACK is the time at which MS realizes contention resolution
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* succeeds:
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* TS 44.060 7.1.2.3: "The contention resolution is successfully completed
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* on the mobile station side when the mobile station receives a
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* PACKET UPLINK ACK/NACK"
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*/
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if (ms_tlli(ms) != GSM_RESERVED_TMSI && !ul_tbf_contention_resolution_done(ctx->tbf))
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osmo_fsm_inst_dispatch(tbf_state_fi(ul_tbf_as_tbf(ctx->tbf)), TBF_EV_CONTENTION_RESOLUTION_MS_SUCCESS, NULL);
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if (final) {
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tbf_set_polling(ul_tbf_as_tbf(tbf), d->pdch, new_poll_fn, PDCH_ULC_POLL_UL_ACK);
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LOGPTBFUL(tbf, LOGL_DEBUG,
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"Scheduled UL Acknowledgement polling on PACCH (FN=%d, TS=%d)\n",
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new_poll_fn, d->pdch->ts_no);
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}
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return msg;
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}
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static void st_none(struct osmo_fsm_inst *fi, uint32_t event, void *data)
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{
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switch (event) {
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case TBF_UL_ACK_EV_SCHED_ACK:
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tbf_ul_ack_fsm_state_chg(fi, TBF_UL_ACK_ST_SCHED_UL_ACK);
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break;
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default:
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OSMO_ASSERT(0);
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}
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}
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static void st_sched_ul_ack(struct osmo_fsm_inst *fi, uint32_t event, void *data)
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{
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struct tbf_ul_ack_fsm_ctx *ctx = (struct tbf_ul_ack_fsm_ctx *)fi->priv;
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struct gprs_rlcmac_ul_tbf *tbf = ctx->tbf;
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struct tbf_ul_ack_ev_create_rlcmac_msg_ctx *data_ctx;
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bool final;
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switch (event) {
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case TBF_UL_ACK_EV_SCHED_ACK:
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LOGPTBFUL(tbf, LOGL_DEBUG,
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"Sending Ack/Nack already scheduled, no need to re-schedule\n");
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break;
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case TBF_UL_ACK_EV_CREATE_RLCMAC_MSG:
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data_ctx = (struct tbf_ul_ack_ev_create_rlcmac_msg_ctx *)data;
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final = tbf_state(ul_tbf_as_tbf(tbf)) == TBF_ST_FINISHED;
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data_ctx->msg = create_ul_ack_nack(ctx, data_ctx, final);
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if (!data_ctx->msg)
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return;
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if (final) /* poll set */
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tbf_ul_ack_fsm_state_chg(fi, TBF_UL_ACK_ST_WAIT_ACK);
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else
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tbf_ul_ack_fsm_state_chg(fi, TBF_UL_ACK_ST_NONE);
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break;
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default:
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OSMO_ASSERT(0);
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}
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}
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static void st_wait_ctrl_ack(struct osmo_fsm_inst *fi, uint32_t event, void *data)
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{
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struct tbf_ul_ack_fsm_ctx *ctx = (struct tbf_ul_ack_fsm_ctx *)fi->priv;
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struct gprs_rlcmac_ul_tbf *tbf = ctx->tbf;
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switch (event) {
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case TBF_UL_ACK_EV_SCHED_ACK:
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/* ignore, we are in the middle of waiting for a response */
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break;
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case TBF_UL_ACK_EV_RX_CTRL_ACK:
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tbf_ul_ack_fsm_state_chg(fi, TBF_UL_ACK_ST_NONE);
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break;
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case TBF_UL_ACK_EV_POLL_TIMEOUT:
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LOGPTBFUL(tbf, LOGL_NOTICE,
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"Timeout for polling PACKET CONTROL ACK for PACKET UPLINK ACK: %s\n",
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tbf_rlcmac_diag(ul_tbf_as_tbf(tbf)));
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/* Reschedule Ul Ack/NAck */
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tbf_ul_ack_fsm_state_chg(fi, TBF_UL_ACK_ST_SCHED_UL_ACK);
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break;
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default:
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OSMO_ASSERT(0);
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}
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}
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static int tbf_ul_ack_fsm_timer_cb(struct osmo_fsm_inst *fi)
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{
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switch (fi->T) {
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default:
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OSMO_ASSERT(0);
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}
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return 0;
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}
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static struct osmo_fsm_state tbf_ul_ack_fsm_states[] = {
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[TBF_UL_ACK_ST_NONE] = {
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.in_event_mask =
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X(TBF_UL_ACK_EV_SCHED_ACK),
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.out_state_mask =
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X(TBF_UL_ACK_ST_SCHED_UL_ACK),
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.name = "NONE",
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.action = st_none,
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},
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[TBF_UL_ACK_ST_SCHED_UL_ACK] = {
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.in_event_mask =
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X(TBF_UL_ACK_EV_SCHED_ACK) |
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X(TBF_UL_ACK_EV_CREATE_RLCMAC_MSG),
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.out_state_mask =
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X(TBF_UL_ACK_ST_NONE) |
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X(TBF_UL_ACK_ST_WAIT_ACK),
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.name = "SCHED_UL_ACK",
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.action = st_sched_ul_ack,
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},
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[TBF_UL_ACK_ST_WAIT_ACK] = {
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.in_event_mask =
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X(TBF_UL_ACK_EV_SCHED_ACK) |
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X(TBF_UL_ACK_EV_RX_CTRL_ACK) |
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X(TBF_UL_ACK_EV_POLL_TIMEOUT),
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.out_state_mask =
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X(TBF_UL_ACK_ST_NONE) |
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X(TBF_UL_ACK_ST_SCHED_UL_ACK),
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.name = "WAIT_ACK",
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.action = st_wait_ctrl_ack,
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},
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};
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struct osmo_fsm tbf_ul_ack_fsm = {
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.name = "UL_ACK_TBF",
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.states = tbf_ul_ack_fsm_states,
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.num_states = ARRAY_SIZE(tbf_ul_ack_fsm_states),
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.timer_cb = tbf_ul_ack_fsm_timer_cb,
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.log_subsys = DTBFUL,
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.event_names = tbf_ul_ack_fsm_event_names,
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};
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static __attribute__((constructor)) void tbf_ul_ack_fsm_init(void)
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{
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OSMO_ASSERT(osmo_fsm_register(&tbf_ul_ack_fsm) == 0);
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}
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struct msgb *tbf_ul_ack_create_rlcmac_msg(const struct gprs_rlcmac_ul_tbf *ul_tbf,
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const struct gprs_rlcmac_pdch *pdch,
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uint32_t fn)
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{
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int rc;
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struct tbf_ul_ack_ev_create_rlcmac_msg_ctx data_ctx = {
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.pdch = pdch,
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.fn = fn,
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.msg = NULL,
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};
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rc = osmo_fsm_inst_dispatch(tbf_ul_ack_fi(ul_tbf), TBF_UL_ACK_EV_CREATE_RLCMAC_MSG, &data_ctx);
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if (rc != 0 || !data_ctx.msg)
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return NULL;
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return data_ctx.msg;
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}
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bool tbf_ul_ack_rts(const struct gprs_rlcmac_ul_tbf *ul_tbf, const struct gprs_rlcmac_pdch *pdch)
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{
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struct osmo_fsm_inst *fi;
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if (!tbf_is_control_ts(ul_tbf_as_tbf_const(ul_tbf), pdch))
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return false;
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fi = tbf_ul_ack_fi(ul_tbf);
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return fi->state == TBF_UL_ACK_ST_SCHED_UL_ACK;
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}
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/* Did we already send the Final ACK and we are waiting for its confirmation (CTRL ACK) ? */
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bool tbf_ul_ack_waiting_cnf_final_ack(const struct gprs_rlcmac_ul_tbf *ul_tbf)
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{
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struct osmo_fsm_inst *fi = tbf_ul_ack_fi(ul_tbf);
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return fi->state == TBF_UL_ACK_ST_WAIT_ACK;
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}
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bool tbf_ul_ack_exp_ctrl_ack(const struct gprs_rlcmac_ul_tbf *ul_tbf, uint32_t fn, uint8_t ts)
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{
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struct osmo_fsm_inst *fi = tbf_ul_ack_fi(ul_tbf);
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return fi->state == TBF_UL_ACK_ST_WAIT_ACK;
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/* FIXME: validate FN and TS match: && ctx->poll_fn = fn && ctx->poll_ts == ts */
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}
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