libosmo-gprs/src/rlcmac/tbf_ul_fsm.c

/* TBF as per 3GPP TS 44.064 */
/*
 * (C) 2023 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
 *
 * All Rights Reserved
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation; either version 3 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include <talloc.h>
#include <osmocom/core/tdef.h>
#include <osmocom/core/fsm.h>

#include <osmocom/gprs/rlcmac/tbf_ul_fsm.h>
#include <osmocom/gprs/rlcmac/tbf_ul.h>
#include <osmocom/gprs/rlcmac/gre.h>

#define X(s) (1 << (s))

static const struct value_string tbf_ul_fsm_event_names[] = {
	{ GPRS_RLCMAC_TBF_UL_EV_UL_ASS_START,		 "UL_ASS_START" },
	{ GPRS_RLCMAC_TBF_UL_EV_UL_ASS_COMPL,		"UL_ASS_COMPL" },
	{ GPRS_RLCMAC_TBF_UL_EV_LAST_UL_DATA_SENT,	"LAST_UL_DATA_SENT" },
	{ GPRS_RLCMAC_TBF_UL_EV_FINAL_ACK_RECVD,	"FINAL_ACK_RECVD" },
	{ 0, NULL }
};

static const struct osmo_tdef_state_timeout tbf_ul_fsm_timeouts[32] = {
	[GPRS_RLCMAC_TBF_UL_ST_NEW] = { },
	[GPRS_RLCMAC_TBF_UL_ST_WAIT_ASSIGN] = { },
	[GPRS_RLCMAC_TBF_UL_ST_FLOW] = { },
	[GPRS_RLCMAC_TBF_UL_ST_FINISHED] = { },
};

/* 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, \
				     g_ctx->T_defs, \
				     -1)

static uint8_t ul_tbf_ul_slotmask(struct gprs_rlcmac_ul_tbf *ul_tbf)
{
	uint8_t i;
	uint8_t ul_slotmask = 0;

	for (i = 0; i < 8; i++) {
		if (ul_tbf->cur_alloc.ts[i].allocated)
			ul_slotmask |= (1 << i);
	}

	return ul_slotmask;
}

static int configure_ul_tbf(struct gprs_rlcmac_tbf_ul_fsm_ctx *ctx)
{
	struct osmo_gprs_rlcmac_prim *rlcmac_prim;
	uint8_t ul_slotmask = ul_tbf_ul_slotmask(ctx->ul_tbf);

	LOGPFSML(ctx->fi, LOGL_INFO, "Send L1CTL-CF_UL_TBF.req ul_slotmask=0x%02x\n", ul_slotmask);
	rlcmac_prim = gprs_rlcmac_prim_alloc_l1ctl_cfg_ul_tbf_req(ctx->tbf->nr, ul_slotmask);
	return gprs_rlcmac_prim_call_down_cb(rlcmac_prim);
}

static void st_new(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
	//struct gprs_rlcmac_tbf_ul_fsm_ctx *ctx = (struct gprs_rlcmac_tbf_ul_fsm_ctx *)fi->priv;
	switch (event) {
	case GPRS_RLCMAC_TBF_UL_EV_UL_ASS_START:
		tbf_ul_fsm_state_chg(fi, GPRS_RLCMAC_TBF_UL_ST_WAIT_ASSIGN);
		break;
	default:
		OSMO_ASSERT(0);
	}
}

static void st_wait_assign(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
	struct gprs_rlcmac_tbf_ul_fsm_ctx *ctx = (struct gprs_rlcmac_tbf_ul_fsm_ctx *)fi->priv;
	switch (event) {
	case GPRS_RLCMAC_TBF_UL_EV_UL_ASS_COMPL:
		/* Configure UL TBF on the lower MAC side: */
		configure_ul_tbf(ctx);
		tbf_ul_fsm_state_chg(fi, GPRS_RLCMAC_TBF_UL_ST_FLOW);
		break;
	default:
		OSMO_ASSERT(0);
	}
}

static void st_flow(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
	//struct gprs_rlcmac_tbf_ul_fsm_ctx *ctx = (struct gprs_rlcmac_tbf_ul_fsm_ctx *)fi->priv;
	switch (event) {
	case GPRS_RLCMAC_TBF_UL_EV_LAST_UL_DATA_SENT:
		tbf_ul_fsm_state_chg(fi, GPRS_RLCMAC_TBF_UL_ST_FINISHED);
		break;
	default:
		OSMO_ASSERT(0);
	}
}

static void st_finished(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
	//struct gprs_rlcmac_tbf_ul_fsm_ctx *ctx = (struct gprs_rlcmac_tbf_ul_fsm_ctx *)fi->priv;
	switch (event) {
	case GPRS_RLCMAC_TBF_UL_EV_FINAL_ACK_RECVD:
		break;
	default:
		OSMO_ASSERT(0);
	}
}

static struct osmo_fsm_state tbf_ul_fsm_states[] = {
	[GPRS_RLCMAC_TBF_UL_ST_NEW] = {
		.in_event_mask =
			X(GPRS_RLCMAC_TBF_UL_EV_UL_ASS_START),
		.out_state_mask =
			X(GPRS_RLCMAC_TBF_UL_ST_WAIT_ASSIGN) |
			X(GPRS_RLCMAC_TBF_UL_ST_FLOW),
		.name = "NEW",
		.action = st_new,
	},
	[GPRS_RLCMAC_TBF_UL_ST_WAIT_ASSIGN] = {
		.in_event_mask =
			X(GPRS_RLCMAC_TBF_UL_EV_UL_ASS_COMPL),
		.out_state_mask =
			X(GPRS_RLCMAC_TBF_UL_ST_FLOW),
		.name = "ASSIGN",
		.action = st_wait_assign,
	},
	[GPRS_RLCMAC_TBF_UL_ST_FLOW] = {
		.in_event_mask =
			X(GPRS_RLCMAC_TBF_UL_EV_LAST_UL_DATA_SENT),
		.out_state_mask =
			X(GPRS_RLCMAC_TBF_UL_ST_FINISHED),
		.name = "FLOW",
		.action = st_flow,
	},
	[GPRS_RLCMAC_TBF_UL_ST_FINISHED] = {
		.in_event_mask =
			X(GPRS_RLCMAC_TBF_UL_EV_FINAL_ACK_RECVD),
		.out_state_mask =
			X(GPRS_RLCMAC_TBF_UL_ST_WAIT_ASSIGN),
		.name = "FINISHED",
		.action = st_finished,
	},
};

static int tbf_ul_fsm_timer_cb(struct osmo_fsm_inst *fi)
{
	struct gprs_rlcmac_tbf_ul_fsm_ctx *ctx = (struct gprs_rlcmac_tbf_ul_fsm_ctx *)fi->priv;
	switch (fi->T) {
	case -2001:
		LOGPTBFUL(ctx->ul_tbf, LOGL_NOTICE, "releasing due to PACCH assignment timeout.\n");
		/* fall-through */
	case 3169:
	case 3195:
		gprs_rlcmac_ul_tbf_free(ctx->ul_tbf);
		break;
	default:
		OSMO_ASSERT(0);
	}
	return 0;
}

static 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 = DLGLOBAL, /* updated dynamically through gprs_rlcmac_tbf_ul_fsm_set_log_cat() */
	.event_names = tbf_ul_fsm_event_names,
};

int gprs_rlcmac_tbf_ul_fsm_init(void)
{
	return osmo_fsm_register(&tbf_ul_fsm);
}

void gprs_rlcmac_tbf_ul_fsm_set_log_cat(int logcat)
{
	tbf_ul_fsm.log_subsys = logcat;
}

int gprs_rlcmac_tbf_ul_fsm_constructor(struct gprs_rlcmac_ul_tbf *ul_tbf)
{
	struct gprs_rlcmac_tbf_ul_fsm_ctx *ctx = &ul_tbf->state_fsm;
	ctx->ul_tbf = ul_tbf;
	ctx->fi = osmo_fsm_inst_alloc(&tbf_ul_fsm, ul_tbf, ctx, LOGL_INFO, NULL);
	if (!ctx->fi)
		return -ENODATA;

	return 0;
}

void gprs_rlcmac_tbf_ul_fsm_destructor(struct gprs_rlcmac_ul_tbf *ul_tbf)
{
	struct gprs_rlcmac_tbf_ul_fsm_ctx *ctx = &ul_tbf->state_fsm;
	osmo_fsm_inst_free(ctx->fi);
	ctx->fi = NULL;
}

enum gprs_rlcmac_tbf_ul_fsm_states gprs_rlcmac_tbf_ul_state(const struct gprs_rlcmac_ul_tbf *ul_tbf)
{
	const struct gprs_rlcmac_tbf_ul_fsm_ctx *ctx = &ul_tbf->state_fsm;
	return ctx->fi->state;
}