Osmocom Packet control Unit (PCU): Network-side GPRS (RLC/MAC); BTS- or BSC-colocated https://osmocom.org/projects/osmopcu
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
osmo-pcu/src/tbf_dl_ass_fsm.c

283 lines
8.3 KiB

/* tbf_dl_ass_fsm.c
*
* Copyright (C) 2021 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <unistd.h>
#include <talloc.h>
#include <osmocom/core/bitvec.h>
#include <tbf_dl_ass_fsm.h>
#include <gprs_rlcmac.h>
#include <gprs_debug.h>
#include <gprs_ms.h>
#include <encoding.h>
#include <bts.h>
#include <tbf.h>
#include <tbf_dl.h>
#define X(s) (1 << (s))
const struct osmo_tdef_state_timeout tbf_dl_ass_fsm_timeouts[32] = {
[TBF_DL_ASS_NONE] = {},
[TBF_DL_ASS_SEND_ASS] = {},
[TBF_DL_ASS_WAIT_ACK] = {},
};
const struct value_string tbf_dl_ass_fsm_event_names[] = {
{ TBF_DL_ASS_EV_SCHED_ASS, "SCHED_ASS" },
{ TBF_DL_ASS_EV_CREATE_RLCMAC_MSG, "CREATE_RLCMAC_MSG" },
{ TBF_DL_ASS_EV_RX_ASS_CTRL_ACK, "RX_ASS_CTRL_ACK" },
{ TBF_DL_ASS_EV_ASS_POLL_TIMEOUT, "ASS_POLL_TIMEOUT" },
{ 0, NULL }
};
struct msgb *create_packet_dl_assign(const struct tbf_dl_ass_fsm_ctx *ctx,
const struct tbf_dl_ass_ev_create_rlcmac_msg_ctx *d)
{
struct msgb *msg;
struct gprs_rlcmac_dl_tbf *new_dl_tbf = NULL;
RlcMacDownlink_t *mac_control_block = NULL;
struct GprsMs *ms = tbf_ms(ctx->tbf);
const int poll_ass_dl = 1;
unsigned int rrbp = 0;
uint32_t new_poll_fn = 0;
int rc;
bool old_tfi_is_valid = tbf_is_tfi_assigned(ctx->tbf);
/* We only use this function in control TS (PACCH) so that MS can always answer the poll */
OSMO_ASSERT(tbf_is_control_ts(ctx->tbf, d->ts));
rc = tbf_check_polling(ctx->tbf, d->fn, d->ts, &new_poll_fn, &rrbp);
if (rc < 0)
return NULL;
new_dl_tbf = ms_dl_tbf(ms);
if (!new_dl_tbf) {
LOGPTBF(ctx->tbf, LOGL_ERROR,
"We have a schedule for downlink assignment, but there is no downlink TBF\n");
tbf_dl_ass_fsm_state_chg(ctx->fi, TBF_DL_ASS_NONE);
return NULL;
}
if (old_tfi_is_valid && ms_tlli(ms) == GSM_RESERVED_TMSI) {
LOGPTBF(ctx->tbf, LOGL_ERROR,
"The old TFI is not assigned and there is no TLLI. New TBF %s\n",
tbf_name((struct gprs_rlcmac_tbf *)new_dl_tbf));
tbf_dl_ass_fsm_state_chg(ctx->fi, TBF_DL_ASS_NONE);
return NULL;
}
msg = msgb_alloc(GSM_MACBLOCK_LEN, "rlcmac_dl_ass");
if (!msg)
return NULL;
/* Initialize a bit vector that uses allocated msgb as the data buffer. */
struct bitvec bv = {
.data = msgb_put(msg, GSM_MACBLOCK_LEN),
.data_len = GSM_MACBLOCK_LEN,
};
bitvec_unhex(&bv, DUMMY_VEC);
if (ctx->tbf != (struct gprs_rlcmac_tbf *)new_dl_tbf)
LOGPTBF(ctx->tbf, LOGL_INFO, "start Packet Downlink Assignment (PACCH) for %s\n",
tbf_name((const struct gprs_rlcmac_tbf *)new_dl_tbf));
else
LOGPTBF(ctx->tbf, LOGL_INFO, "start Packet Downlink Assignment (PACCH)\n");
mac_control_block = (RlcMacDownlink_t *)talloc_zero(ctx->tbf, RlcMacDownlink_t);
write_packet_downlink_assignment(mac_control_block, old_tfi_is_valid,
tbf_tfi(ctx->tbf), (tbf_direction(ctx->tbf) == GPRS_RLCMAC_DL_TBF),
new_dl_tbf, poll_ass_dl, rrbp,
bts_get_ms_pwr_alpha(ms->bts), the_pcu->vty.gamma, -1, 0,
tbf_is_egprs_enabled(ctx->tbf), tbf_state(ctx->tbf) == TBF_ST_WAIT_RELEASE);
LOGP(DTBF, LOGL_DEBUG, "+++++++++++++++++++++++++ TX : Packet Downlink Assignment +++++++++++++++++++++++++\n");
rc = encode_gsm_rlcmac_downlink(&bv, mac_control_block);
if (rc < 0) {
LOGP(DTBF, LOGL_ERROR, "Encoding of Packet Downlink Ass failed (%d)\n", rc);
goto free_ret;
}
LOGP(DTBF, LOGL_DEBUG, "------------------------- TX : Packet Downlink Assignment -------------------------\n");
bts_do_rate_ctr_inc(ms->bts, CTR_PKT_DL_ASSIGNMENT);
tbf_set_polling(ctx->tbf, new_poll_fn, d->ts, PDCH_ULC_POLL_DL_ASS);
LOGPTBFDL(ctx->tbf, LOGL_INFO, "Scheduled DL Assignment polling on PACCH (FN=%d, TS=%d)\n",
new_poll_fn, d->ts);
talloc_free(mac_control_block);
return msg;
free_ret:
talloc_free(mac_control_block);
msgb_free(msg);
return NULL;
}
static void st_none_on_enter(struct osmo_fsm_inst *fi, uint32_t prev_state)
{
}
static void st_none(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
switch (event) {
case TBF_DL_ASS_EV_SCHED_ASS:
tbf_dl_ass_fsm_state_chg(fi, TBF_DL_ASS_SEND_ASS);
break;
default:
OSMO_ASSERT(0);
}
}
static void st_send_ass(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
struct tbf_dl_ass_fsm_ctx *ctx = (struct tbf_dl_ass_fsm_ctx *)fi->priv;
struct tbf_dl_ass_ev_create_rlcmac_msg_ctx *data_ctx;
switch (event) {
case TBF_DL_ASS_EV_CREATE_RLCMAC_MSG:
data_ctx = (struct tbf_dl_ass_ev_create_rlcmac_msg_ctx *)data;
data_ctx->msg = create_packet_dl_assign(ctx, data_ctx);
if (!data_ctx->msg)
return;
tbf_dl_ass_fsm_state_chg(fi, TBF_DL_ASS_WAIT_ACK);
break;
default:
OSMO_ASSERT(0);
}
}
static void st_wait_ack(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
struct tbf_dl_ass_fsm_ctx *ctx = (struct tbf_dl_ass_fsm_ctx *)fi->priv;
switch (event) {
case TBF_DL_ASS_EV_RX_ASS_CTRL_ACK:
tbf_dl_ass_fsm_state_chg(fi, TBF_DL_ASS_NONE);
break;
case TBF_DL_ASS_EV_ASS_POLL_TIMEOUT:
LOGPTBF(ctx->tbf, LOGL_NOTICE,
"Timeout for polling PACKET CONTROL ACK for PACKET DOWNLINK ASSIGNMENT: %s\n",
tbf_rlcmac_diag(ctx->tbf));
/* Reschedule Pkt Dl Ass */
tbf_dl_ass_fsm_state_chg(fi, TBF_DL_ASS_SEND_ASS);
break;
default:
OSMO_ASSERT(0);
}
}
static int tbf_dl_ass_fsm_timer_cb(struct osmo_fsm_inst *fi)
{
struct tbf_dl_ass_fsm_ctx *ctx = (struct tbf_dl_ass_fsm_ctx *)fi->priv;
switch (fi->T) {
case -2000:
tbf_free(ctx->tbf);
break;
default:
OSMO_ASSERT(0);
}
return 0;
}
static struct osmo_fsm_state tbf_dl_ass_fsm_states[] = {
[TBF_DL_ASS_NONE] = {
.in_event_mask =
X(TBF_DL_ASS_EV_SCHED_ASS),
.out_state_mask =
X(TBF_DL_ASS_SEND_ASS),
.name = "NONE",
.action = st_none,
.onenter = st_none_on_enter,
},
[TBF_DL_ASS_SEND_ASS] = {
.in_event_mask = X(TBF_DL_ASS_EV_CREATE_RLCMAC_MSG),
.out_state_mask =
X(TBF_DL_ASS_WAIT_ACK) |
X(TBF_DL_ASS_NONE),
.name = "SEND_ASS",
.action = st_send_ass,
},
[TBF_DL_ASS_WAIT_ACK] = {
.in_event_mask =
X(TBF_DL_ASS_EV_RX_ASS_CTRL_ACK) |
X(TBF_DL_ASS_EV_ASS_POLL_TIMEOUT),
.out_state_mask =
X(TBF_DL_ASS_NONE) |
X(TBF_DL_ASS_SEND_ASS),
.name = "WAIT_ACK",
.action = st_wait_ack,
},
};
struct osmo_fsm tbf_dl_ass_fsm = {
.name = "DL_ASS_TBF",
.states = tbf_dl_ass_fsm_states,
.num_states = ARRAY_SIZE(tbf_dl_ass_fsm_states),
.timer_cb = tbf_dl_ass_fsm_timer_cb,
.log_subsys = DTBF,
.event_names = tbf_dl_ass_fsm_event_names,
};
static __attribute__((constructor)) void tbf_dl_ass_fsm_init(void)
{
OSMO_ASSERT(osmo_fsm_register(&tbf_dl_ass_fsm) == 0);
}
struct msgb *tbf_dl_ass_create_rlcmac_msg(const struct gprs_rlcmac_tbf* tbf, uint32_t fn, uint8_t ts)
{
int rc;
struct tbf_dl_ass_ev_create_rlcmac_msg_ctx data_ctx = {
.fn = fn,
.ts = ts,
.msg = NULL,
};
rc = osmo_fsm_inst_dispatch(tbf_dl_ass_fi(tbf), TBF_DL_ASS_EV_CREATE_RLCMAC_MSG, &data_ctx);
if (rc != 0 || !data_ctx.msg)
return NULL;
return data_ctx.msg;
}
bool tbf_dl_ass_rts(const struct gprs_rlcmac_tbf *tbf)
{
struct osmo_fsm_inst *fi = tbf_dl_ass_fi(tbf);
if (fi->state != TBF_DL_ASS_SEND_ASS)
return false;
if (tbf_ul_ass_fi(tbf)->state == TBF_UL_ASS_WAIT_ACK) {
LOGPTBF(tbf, LOGL_DEBUG,
"Polling is already scheduled, so we must wait for the uplink assignment...\n");
return false;
}
/* on uplink TBF we get the downlink TBF to be assigned. */
if (tbf_direction(tbf) == GPRS_RLCMAC_UL_TBF) {
const struct gprs_rlcmac_ul_tbf *ul_tbf = (const struct gprs_rlcmac_ul_tbf *)tbf;
/* be sure to check first, if contention resolution is done,
* otherwise we cannot send the assignment yet (3GPP TS 44.060 sec 7.1.3.1) */
if (!ul_tbf_contention_resolution_done(ul_tbf)) {
LOGPTBF(tbf, LOGL_DEBUG,
"Cannot assign DL TBF now, because contention resolution is not finished.\n");
return false;
}
}
return true;
}