471 lines
14 KiB
C
471 lines
14 KiB
C
/* tbf_dl_fsm.c
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*
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* Copyright (C) 2021-2022 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 <tbf_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 <bts_pch_timer.h>
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#define X(s) (1 << (s))
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static const struct osmo_tdef_state_timeout tbf_dl_fsm_timeouts[32] = {
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[TBF_ST_NEW] = {},
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[TBF_ST_ASSIGN] = { },
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[TBF_ST_FLOW] = { },
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[TBF_ST_FINISHED] = {},
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[TBF_ST_WAIT_RELEASE] = {},
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[TBF_ST_RELEASING] = {},
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};
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/* Transition to a state, using the T timer defined in tbf_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_dl_fsm_state_chg(fi, NEXT_STATE) \
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osmo_tdef_fsm_inst_state_chg(fi, NEXT_STATE, \
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tbf_dl_fsm_timeouts, \
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the_pcu->T_defs, \
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-1)
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static void mod_ass_type(struct tbf_dl_fsm_ctx *ctx, uint8_t t, bool set)
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{
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const char *ch = "UNKNOWN";
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bool prev_set = ctx->state_flags & (1 << t);
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switch (t) {
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case GPRS_RLCMAC_FLAG_CCCH:
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ch = "CCCH";
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break;
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case GPRS_RLCMAC_FLAG_PACCH:
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ch = "PACCH";
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break;
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default:
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LOGPTBFDL(ctx->dl_tbf, LOGL_ERROR,
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"attempted to %sset unexpected ass. type %d - FIXME!\n",
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set ? "" : "un", t);
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return;
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}
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if (set && prev_set)
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LOGPTBFDL(ctx->dl_tbf, LOGL_ERROR,
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"attempted to set ass. type %s which is already set.\n", ch);
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else if (!set && !prev_set)
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return;
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LOGPTBFDL(ctx->dl_tbf, LOGL_INFO, "%sset ass. type %s [prev CCCH:%u, PACCH:%u]\n",
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set ? "" : "un", ch,
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!!(ctx->state_flags & (1 << GPRS_RLCMAC_FLAG_CCCH)),
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!!(ctx->state_flags & (1 << GPRS_RLCMAC_FLAG_PACCH)));
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if (set) {
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ctx->state_flags |= (1 << t);
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} else {
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ctx->state_flags &= GPRS_RLCMAC_FLAG_TO_MASK; /* keep to flags */
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ctx->state_flags &= ~(1 << t);
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}
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}
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static void st_new(struct osmo_fsm_inst *fi, uint32_t event, void *data)
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{
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struct tbf_dl_fsm_ctx *ctx = (struct tbf_dl_fsm_ctx *)fi->priv;
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switch (event) {
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case TBF_EV_ASSIGN_ADD_CCCH:
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mod_ass_type(ctx, GPRS_RLCMAC_FLAG_CCCH, true);
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tbf_dl_fsm_state_chg(fi, TBF_ST_ASSIGN);
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break;
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case TBF_EV_ASSIGN_ADD_PACCH:
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mod_ass_type(ctx, GPRS_RLCMAC_FLAG_PACCH, true);
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tbf_dl_fsm_state_chg(fi, TBF_ST_ASSIGN);
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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_assign_on_enter(struct osmo_fsm_inst *fi, uint32_t prev_state)
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{
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struct tbf_dl_fsm_ctx *ctx = (struct tbf_dl_fsm_ctx *)fi->priv;
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unsigned long val;
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unsigned int sec, micro;
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/* If assignment for this TBF is happening on PACCH, that means the
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* actual Assignment procedure (tx/rx) is happening on another TBF (eg
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* Ul TBF vs DL TBF). Hence we add a security timer here to free it in
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* case the other TBF doesn't succeed in informing (assigning) the MS
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* about this TBF, or simply because the scheduler takes too long to
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* schedule it. This timer can probably be dropped once we make the
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* other TBF always signal us assignment failure (we already get
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* assignment success through TBF_EV_ASSIGN_ACK_PACCH) */
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if (ctx->state_flags & (1 << GPRS_RLCMAC_FLAG_PACCH)) {
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fi->T = -2001;
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val = osmo_tdef_get(the_pcu->T_defs, fi->T, OSMO_TDEF_MS, -1);
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sec = val / 1000;
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micro = (val % 1000) * 1000;
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LOGPTBFDL(ctx->dl_tbf, LOGL_DEBUG,
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"Starting timer X2001 [assignment (PACCH)] with %u sec. %u microsec\n",
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sec, micro);
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osmo_timer_schedule(&fi->timer, sec, micro);
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} else {
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/* GPRS_RLCMAC_FLAG_CCCH is set, so here we submitted an DL Ass
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* through PCUIF on CCCH */
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}
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}
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static void st_assign(struct osmo_fsm_inst *fi, uint32_t event, void *data)
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{
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struct tbf_dl_fsm_ctx *ctx = (struct tbf_dl_fsm_ctx *)fi->priv;
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unsigned long val;
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unsigned int sec, micro;
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switch (event) {
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case TBF_EV_ASSIGN_ADD_CCCH:
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mod_ass_type(ctx, GPRS_RLCMAC_FLAG_CCCH, true);
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break;
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case TBF_EV_ASSIGN_ADD_PACCH:
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mod_ass_type(ctx, GPRS_RLCMAC_FLAG_PACCH, true);
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break;
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case TBF_EV_ASSIGN_ACK_PACCH:
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tbf_assign_control_ts(ctx->tbf);
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if (ctx->state_flags & (1 << GPRS_RLCMAC_FLAG_CCCH)) {
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/* We now know that the PACCH really existed */
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LOGPTBFDL(ctx->dl_tbf, LOGL_INFO,
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"The TBF has been confirmed on the PACCH, "
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"changed type from CCCH to PACCH\n");
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mod_ass_type(ctx, GPRS_RLCMAC_FLAG_CCCH, false);
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mod_ass_type(ctx, GPRS_RLCMAC_FLAG_PACCH, true);
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}
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tbf_dl_fsm_state_chg(fi, TBF_ST_FLOW);
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break;
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case TBF_EV_ASSIGN_PCUIF_CNF:
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/* BTS informs us it sent Imm Ass for DL TBF over CCCH. We now
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* have to wait for X2002 to trigger (meaning MS is already
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* listening on PDCH) in order to move to FLOW state and start
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* transmitting data to it. When X2002 triggers (see cb timer
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* end of the file) it will send TBF_EV_ASSIGN_READY_CCCH back
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* to us here.
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*/
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if (!(ctx->state_flags & (1 << GPRS_RLCMAC_FLAG_CCCH))) {
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/* This can happen if we initiated a CCCH DlAss from an
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* older TBF object (same TLLI) towards BTS, and the DL-TBF
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* was recreated and is now trying to be assigned throguh
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* PACCH.
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*/
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LOGPTBFDL(ctx->dl_tbf, LOGL_INFO,
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"Ignoring event ASSIGN_PCUIF_CNF from BTS "
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"(CCCH was not requested on current assignment)\n");
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break;
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}
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fi->T = -2002;
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val = osmo_tdef_get(the_pcu->T_defs, fi->T, OSMO_TDEF_MS, -1);
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sec = val / 1000;
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micro = (val % 1000) * 1000;
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LOGPTBFDL(ctx->dl_tbf, LOGL_DEBUG,
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"Starting timer X2002 [assignment (AGCH)] with %u sec. %u microsec\n",
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sec, micro);
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osmo_timer_schedule(&fi->timer, sec, micro);
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break;
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case TBF_EV_ASSIGN_READY_CCCH:
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/* change state to FLOW, so scheduler will start transmission */
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tbf_dl_fsm_state_chg(fi, TBF_ST_FLOW);
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break;
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case TBF_EV_MAX_N3105:
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/* We are going to release, so abort any Pkt Ul Ass pending to be scheduled: */
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osmo_fsm_inst_dispatch(tbf_ul_ass_fi(ctx->tbf), TBF_UL_ASS_EV_ABORT, NULL);
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ctx->T_release = 3195;
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tbf_dl_fsm_state_chg(fi, TBF_ST_RELEASING);
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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_flow(struct osmo_fsm_inst *fi, uint32_t event, void *data)
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{
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struct tbf_dl_fsm_ctx *ctx = (struct tbf_dl_fsm_ctx *)fi->priv;
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switch (event) {
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case TBF_EV_DL_ACKNACK_MISS:
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/* DL TBF: we missed a DL ACK/NACK. If we started assignment
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* over CCCH and never received any DL ACK/NACK yet, it means we
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* don't even know if the MS successfully received the Imm Ass on
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* CCCH and hence is listening on PDCH. Let's better refrain
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* from continuing and start assignment on CCCH again */
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if ((ctx->state_flags & (1 << GPRS_RLCMAC_FLAG_CCCH))
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&& !(ctx->state_flags & (1 << GPRS_RLCMAC_FLAG_DL_ACK))) {
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struct GprsMs *ms = tbf_ms(ctx->tbf);
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LOGPTBFDL(ctx->dl_tbf, LOGL_DEBUG,
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"Re-send downlink assignment on PCH (IMSI=%s)\n",
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ms_imsi_is_valid(ms) ? ms_imsi(ms) : "");
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tbf_dl_fsm_state_chg(fi, TBF_ST_ASSIGN);
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/* send immediate assignment */
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bts_snd_dl_ass(ms->bts, ctx->dl_tbf);
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}
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break;
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case TBF_EV_LAST_DL_DATA_SENT:
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/* All data has been sent or received, change state to FINISHED */
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tbf_dl_fsm_state_chg(fi, TBF_ST_FINISHED);
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break;
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case TBF_EV_FINAL_ACK_RECVD:
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/* We received Final Ack (DL ACK/NACK) from MS. move to
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* WAIT_RELEASE, we wait there for release or re-use the TBF in
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* case we receive more DL data to tx */
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tbf_dl_fsm_state_chg(fi, TBF_ST_WAIT_RELEASE);
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break;
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case TBF_EV_MAX_N3105:
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ctx->T_release = 3195;
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tbf_dl_fsm_state_chg(fi, TBF_ST_RELEASING);
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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_finished(struct osmo_fsm_inst *fi, uint32_t event, void *data)
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{
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struct tbf_dl_fsm_ctx *ctx = (struct tbf_dl_fsm_ctx *)fi->priv;
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switch (event) {
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case TBF_EV_DL_ACKNACK_MISS:
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OSMO_ASSERT(tbf_direction(ctx->tbf) == GPRS_RLCMAC_DL_TBF);
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break;
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case TBF_EV_FINAL_ACK_RECVD:
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/* We received Final Ack (DL ACK/NACK) from MS. move to
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* WAIT_RELEASE, we wait there for release or re-use the TBF in
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* case we receive more DL data to tx */
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tbf_dl_fsm_state_chg(fi, TBF_ST_WAIT_RELEASE);
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break;
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case TBF_EV_MAX_N3105:
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ctx->T_release = 3195;
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tbf_dl_fsm_state_chg(fi, TBF_ST_RELEASING);
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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_release_on_enter(struct osmo_fsm_inst *fi, uint32_t prev_state)
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{
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struct tbf_dl_fsm_ctx *ctx = (struct tbf_dl_fsm_ctx *)fi->priv;
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unsigned long val_s, val_ms, val_us;
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fi->T = 3193;
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val_ms = osmo_tdef_get(tbf_ms(ctx->tbf)->bts->T_defs_bts, fi->T, OSMO_TDEF_MS, -1);
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val_s = val_ms / 1000;
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val_us = (val_ms % 1000) * 1000;
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LOGPTBFDL(ctx->dl_tbf, LOGL_DEBUG, "starting timer T%u with %lu sec. %lu microsec\n",
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fi->T, val_s, val_us);
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osmo_timer_schedule(&fi->timer, val_s, val_us);
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mod_ass_type(ctx, GPRS_RLCMAC_FLAG_CCCH, false);
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}
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static void st_wait_release(struct osmo_fsm_inst *fi, uint32_t event, void *data)
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{
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struct tbf_dl_fsm_ctx *ctx = (struct tbf_dl_fsm_ctx *)fi->priv;
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switch (event) {
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case TBF_EV_FINAL_ACK_RECVD:
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/* ignore, duplicate ACK, we already know about since we are in WAIT_RELEASE */
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break;
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case TBF_EV_MAX_N3105:
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ctx->T_release = 3195;
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tbf_dl_fsm_state_chg(fi, TBF_ST_RELEASING);
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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_releasing_on_enter(struct osmo_fsm_inst *fi, uint32_t prev_state)
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{
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struct tbf_dl_fsm_ctx *ctx = (struct tbf_dl_fsm_ctx *)fi->priv;
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unsigned long val;
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if (!ctx->T_release)
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return;
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/* In general we should end up here with an assigned timer in ctx->T_release. Possible values are:
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* T3195: Wait for reuse of TFI(s) when there is no response from the MS
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* (radio failure or cell change) for this TBF/MBMS radio bearer.
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* T3169: Wait for reuse of USF and TFI(s) after the MS uplink assignment for this TBF is invalid.
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*/
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val = osmo_tdef_get(tbf_ms(ctx->tbf)->bts->T_defs_bts, ctx->T_release, OSMO_TDEF_S, -1);
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fi->T = ctx->T_release;
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LOGPTBFDL(ctx->dl_tbf, LOGL_DEBUG, "starting timer T%u with %lu sec. %u microsec\n",
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ctx->T_release, val, 0);
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osmo_timer_schedule(&fi->timer, val, 0);
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}
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static void st_releasing(struct osmo_fsm_inst *fi, uint32_t event, void *data)
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{
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struct tbf_dl_fsm_ctx *ctx = (struct tbf_dl_fsm_ctx *)fi->priv;
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switch (event) {
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case TBF_EV_DL_ACKNACK_MISS:
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OSMO_ASSERT(tbf_direction(ctx->tbf) == GPRS_RLCMAC_DL_TBF);
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/* Ignore, we don't care about missed DL ACK/NACK poll timeouts
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* anymore, we are already releasing the TBF */
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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 handle_timeout_X2002(struct osmo_fsm_inst *fi)
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{
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struct tbf_dl_fsm_ctx *ctx = (struct tbf_dl_fsm_ctx *)fi->priv;
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int rc;
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if (fi->state != TBF_ST_ASSIGN) {
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LOGPTBFDL(ctx->dl_tbf, LOGL_NOTICE, "Continue flow after IMM.ASS confirm\n");
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return;
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}
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/* state TBF_ST_ASSIGN: */
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tbf_assign_control_ts(ctx->tbf);
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if (!tbf_can_upgrade_to_multislot(ctx->tbf)) {
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/* change state to FLOW, so scheduler will start transmission */
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osmo_fsm_inst_dispatch(fi, TBF_EV_ASSIGN_READY_CCCH, NULL);
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return;
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}
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/* This tbf can be upgraded to use multiple DL timeslots and now that there is already
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* one slot assigned send another DL assignment via PDCH.
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*/
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/* keep TO flags */
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ctx->state_flags &= GPRS_RLCMAC_FLAG_TO_MASK;
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rc = dl_tbf_upgrade_to_multislot(ctx->dl_tbf);
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if (rc < 0)
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tbf_free(ctx->tbf);
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}
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static int tbf_dl_fsm_timer_cb(struct osmo_fsm_inst *fi)
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{
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struct tbf_dl_fsm_ctx *ctx = (struct tbf_dl_fsm_ctx *)fi->priv;
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switch (fi->T) {
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case -2002:
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handle_timeout_X2002(fi);
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break;
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case -2001:
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LOGPTBFDL(ctx->dl_tbf, LOGL_NOTICE, "releasing due to PACCH assignment timeout.\n");
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/* fall-through */
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case 3169:
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case 3193:
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case 3195:
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tbf_free(ctx->tbf);
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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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return 0;
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}
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static struct osmo_fsm_state tbf_dl_fsm_states[] = {
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[TBF_ST_NEW] = {
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.in_event_mask =
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X(TBF_EV_ASSIGN_ADD_CCCH) |
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X(TBF_EV_ASSIGN_ADD_PACCH),
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.out_state_mask =
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X(TBF_ST_ASSIGN) |
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X(TBF_ST_RELEASING),
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.name = "NEW",
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.action = st_new,
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},
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[TBF_ST_ASSIGN] = {
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.in_event_mask =
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X(TBF_EV_ASSIGN_ADD_CCCH) |
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X(TBF_EV_ASSIGN_ADD_PACCH) |
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X(TBF_EV_ASSIGN_ACK_PACCH) |
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X(TBF_EV_ASSIGN_PCUIF_CNF) |
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X(TBF_EV_ASSIGN_READY_CCCH) |
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X(TBF_EV_MAX_N3105),
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.out_state_mask =
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X(TBF_ST_FLOW) |
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X(TBF_ST_FINISHED) |
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X(TBF_ST_RELEASING),
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.name = "ASSIGN",
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.action = st_assign,
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.onenter = st_assign_on_enter,
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},
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[TBF_ST_FLOW] = {
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.in_event_mask =
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X(TBF_EV_DL_ACKNACK_MISS) |
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X(TBF_EV_LAST_DL_DATA_SENT) |
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X(TBF_EV_FINAL_ACK_RECVD) |
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X(TBF_EV_MAX_N3105),
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.out_state_mask =
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X(TBF_ST_ASSIGN) |
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X(TBF_ST_FINISHED) |
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X(TBF_ST_WAIT_RELEASE) |
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X(TBF_ST_RELEASING),
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.name = "FLOW",
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.action = st_flow,
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},
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[TBF_ST_FINISHED] = {
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.in_event_mask =
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|
X(TBF_EV_DL_ACKNACK_MISS) |
|
|
X(TBF_EV_FINAL_ACK_RECVD) |
|
|
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_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_dl_fsm = {
|
|
.name = "DL_TBF",
|
|
.states = tbf_dl_fsm_states,
|
|
.num_states = ARRAY_SIZE(tbf_dl_fsm_states),
|
|
.timer_cb = tbf_dl_fsm_timer_cb,
|
|
.log_subsys = DTBFDL,
|
|
.event_names = tbf_fsm_event_names,
|
|
};
|
|
|
|
static __attribute__((constructor)) void tbf_dl_fsm_init(void)
|
|
{
|
|
OSMO_ASSERT(osmo_fsm_register(&tbf_dl_fsm) == 0);
|
|
}
|