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/* (C) 2018 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
*
* Author: Stefan Sperling <ssperling@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 <strings.h>
#include <errno.h>
#include <stdbool.h>
#include <osmocom/bsc/debug.h>
#include <osmocom/bsc/acc_ramp.h>
#include <osmocom/bsc/gsm_data.h>
/*
* Check if an ACC has been permanently barred for a BTS,
* e.g. with the 'rach access-control-class' VTY command.
*/
static bool acc_is_enabled(struct gsm_bts *bts, unsigned int acc)
{
OSMO_ASSERT(acc >= 0 && acc <= 9);
if (acc == 8 || acc == 9)
return (bts->si_common.rach_control.t2 & (1 << (acc - 8))) == 0;
return (bts->si_common.rach_control.t3 & (1 << (acc))) == 0;
}
static void allow_one_acc(struct acc_ramp *acc_ramp, unsigned int acc)
{
OSMO_ASSERT(acc >= 0 && acc <= 9);
if (acc_ramp->barred_accs & (1 << acc))
LOGP(DRSL, LOGL_DEBUG, "(bts=%d) ACC RAMP: allowing Access Control Class %u\n", acc_ramp->bts->nr, acc);
acc_ramp->barred_accs &= ~(1 << acc);
}
static void barr_one_acc(struct acc_ramp *acc_ramp, unsigned int acc)
{
OSMO_ASSERT(acc >= 0 && acc <= 9);
if ((acc_ramp->barred_accs & (1 << acc)) == 0)
LOGP(DRSL, LOGL_DEBUG, "(bts=%d) ACC RAMP: barring Access Control Class %u\n", acc_ramp->bts->nr, acc);
acc_ramp->barred_accs |= (1 << acc);
}
static void barr_all_enabled_accs(struct acc_ramp *acc_ramp)
{
unsigned int acc;
for (acc = 0; acc < 10; acc++) {
if (acc_is_enabled(acc_ramp->bts, acc))
barr_one_acc(acc_ramp, acc);
}
}
static void allow_all_enabled_accs(struct acc_ramp *acc_ramp)
{
unsigned int acc;
for (acc = 0; acc < 10; acc++) {
if (acc_is_enabled(acc_ramp->bts, acc))
allow_one_acc(acc_ramp, acc);
}
}
static unsigned int get_next_step_interval(struct acc_ramp *acc_ramp)
{
struct gsm_bts *bts = acc_ramp->bts;
uint64_t load;
if (acc_ramp->step_interval_is_fixed)
return acc_ramp->step_interval_sec;
/* Scale the step interval to current channel load average. */
load = (bts->chan_load_avg << 8); /* convert to fixed-point */
acc_ramp->step_interval_sec = ((load * ACC_RAMP_STEP_INTERVAL_MAX) / 100) >> 8;
if (acc_ramp->step_interval_sec < ACC_RAMP_STEP_SIZE_MIN)
acc_ramp->step_interval_sec = ACC_RAMP_STEP_INTERVAL_MIN;
else if (acc_ramp->step_interval_sec > ACC_RAMP_STEP_INTERVAL_MAX)
acc_ramp->step_interval_sec = ACC_RAMP_STEP_INTERVAL_MAX;
LOGP(DRSL, LOGL_DEBUG, "(bts=%d) ACC RAMP: step interval set to %u seconds based on %u%% channel load average\n",
bts->nr, acc_ramp->step_interval_sec, bts->chan_load_avg);
return acc_ramp->step_interval_sec;
}
static void do_acc_ramping_step(void *data)
{
struct acc_ramp *acc_ramp = data;
int i;
/* Shortcut in case we only do one ramping step. */
if (acc_ramp->step_size == ACC_RAMP_STEP_SIZE_MAX) {
allow_all_enabled_accs(acc_ramp);
gsm_bts_set_system_infos(acc_ramp->bts);
return;
}
/* Allow 'step_size' ACCs, starting from ACC0. ACC9 will be allowed last. */
for (i = 0; i < acc_ramp->step_size; i++) {
int idx = ffs(acc_ramp_get_barred_t3(acc_ramp));
if (idx > 0) {
/* One of ACC0-ACC7 is still bared. */
unsigned int acc = idx - 1;
if (acc_is_enabled(acc_ramp->bts, acc))
allow_one_acc(acc_ramp, acc);
} else {
idx = ffs(acc_ramp_get_barred_t2(acc_ramp));
if (idx == 1 || idx == 2) {
/* ACC8 or ACC9 is still barred. */
unsigned int acc = idx - 1 + 8;
if (acc_is_enabled(acc_ramp->bts, acc))
allow_one_acc(acc_ramp, acc);
} else {
/* All ACCs are now allowed. */
break;
}
}
}
gsm_bts_set_system_infos(acc_ramp->bts);
/* If we have not allowed all ACCs yet, schedule another ramping step. */
if (acc_ramp_get_barred_t2(acc_ramp) != 0x00 ||
acc_ramp_get_barred_t3(acc_ramp) != 0x00)
osmo_timer_schedule(&acc_ramp->step_timer, get_next_step_interval(acc_ramp), 0);
}
/*!
* Initialize an acc_ramp data structure.
* Storage for this structure must be provided by the caller.
*
* If ACC ramping is enabled, all ACCs are denied by default.
* A subsequent call to acc_ramp_start() will begin the ramping process.
* If ACC ramping is disabled, all ACCs will be allowed by default,
* and there is no need to do anything else.
*
* \param[in] acc_ramp Pointer to acc_ramp structure to be initialized.
* \param[in] enable Indicates whether ACC ramping should be enabled or disabled.
* \param[in] bts BTS which uses this ACC ramp data structure.
*/
void acc_ramp_init(struct acc_ramp *acc_ramp, bool enable, struct gsm_bts *bts)
{
acc_ramp->bts = bts;
acc_ramp->acc_ramping_enabled = enable;
acc_ramp->step_size = ACC_RAMP_STEP_SIZE_DEFAULT;
acc_ramp->step_interval_sec = ACC_RAMP_STEP_INTERVAL_MIN;
acc_ramp->step_interval_is_fixed = false;
osmo_timer_setup(&acc_ramp->step_timer, do_acc_ramping_step, acc_ramp);
if (acc_ramp->acc_ramping_enabled)
barr_all_enabled_accs(acc_ramp);
else
allow_all_enabled_accs(acc_ramp);
}
/*!
* Change the ramping step size which controls how many ACCs will be allowed per ramping step.
* Returns negative on error (step_size out of range), else zero.
* \param[in] acc_ramp Pointer to acc_ramp structure.
* \param[in] step_size The new step size value.
*/
int acc_ramp_set_step_size(struct acc_ramp *acc_ramp, unsigned int step_size)
{
if (step_size < ACC_RAMP_STEP_SIZE_MIN || step_size > ACC_RAMP_STEP_SIZE_MAX)
return -ERANGE;
acc_ramp->step_size = step_size;
LOGP(DRSL, LOGL_DEBUG, "(bts=%d) ACC RAMP: ramping step size set to %u\n", acc_ramp->bts->nr, step_size);
return 0;
}
/*!
* Change the ramping step interval to a fixed value. Unless this function is called,
* the interval is automatically scaled to the BTS channel load average.
* \param[in] acc_ramp Pointer to acc_ramp structure.
* \param[in] step_interval The new fixed step interval in seconds.
*/
int acc_ramp_set_step_interval(struct acc_ramp *acc_ramp, unsigned int step_interval)
{
if (step_interval < ACC_RAMP_STEP_INTERVAL_MIN || step_interval > ACC_RAMP_STEP_INTERVAL_MAX)
return -ERANGE;
acc_ramp->step_interval_sec = step_interval;
acc_ramp->step_interval_is_fixed = true;
LOGP(DRSL, LOGL_DEBUG, "(bts=%d) ACC RAMP: ramping step interval set to %u seconds\n",
acc_ramp->bts->nr, step_interval);
return 0;
}
/*!
* Clear a previously set fixed ramping step interval, so that the interval
* is again automatically scaled to the BTS channel load average.
* \param[in] acc_ramp Pointer to acc_ramp structure.
*/
void acc_ramp_set_step_interval_dynamic(struct acc_ramp *acc_ramp)
{
acc_ramp->step_interval_is_fixed = false;
LOGP(DRSL, LOGL_DEBUG, "(bts=%d) ACC RAMP: ramping step interval set to 'dynamic'\n",
acc_ramp->bts->nr);
}
/*!
* Begin the ramping process. Perform at least one ramping step to allow 'step_size' ACCs.
* If 'step_size' is ACC_RAMP_STEP_SIZE_MAX, all ACCs will be allowed immediately.
* \param[in] acc_ramp Pointer to acc_ramp structure.
*/
void acc_ramp_start(struct acc_ramp *acc_ramp)
{
/* Abort any previously running ramping process. */
acc_ramp_abort(acc_ramp);
/* Set all availble ACCs to barred and start ramping up. */
barr_all_enabled_accs(acc_ramp);
do_acc_ramping_step(acc_ramp);
}
/*!
* Abort the ramping process. If ramping is disabled or has already finished,
* then this function has no effect.
* \param[in] acc_ramp Pointer to acc_ramp structure.
*/
void acc_ramp_abort(struct acc_ramp *acc_ramp)
{
if (osmo_timer_pending(&acc_ramp->step_timer))
osmo_timer_del(&acc_ramp->step_timer);
}
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