diff options
Diffstat (limited to 'openbsc/src/libbsc/acc_ramp.c')
| -rw-r--r-- | openbsc/src/libbsc/acc_ramp.c | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/openbsc/src/libbsc/acc_ramp.c b/openbsc/src/libbsc/acc_ramp.c new file mode 100644 index 000000000..08810b5b8 --- /dev/null +++ b/openbsc/src/libbsc/acc_ramp.c @@ -0,0 +1,236 @@ +/* (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 <openbsc/debug.h> +#include <openbsc/acc_ramp.h> +#include <openbsc/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); + 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); + 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); +} + |