| /* (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/>. |
| * |
| */ |
| |
| #pragma once |
| |
| #include <stdbool.h> |
| #include <stdint.h> |
| |
| #include <osmocom/core/timer.h> |
| #include <osmocom/gsm/protocol/gsm_04_08.h> |
| |
| /*! |
| * Access control class (ACC) ramping is used to slowly make the cell available to |
| * an increasing number of MS. This avoids overload at startup time in cases where |
| * a lot of MS would discover the new cell and try to connect to it all at once. |
| */ |
| |
| #define ACC_RAMP_STEP_SIZE_MIN 1 /* allow at most 1 new ACC per ramp step */ |
| #define ACC_RAMP_STEP_SIZE_DEFAULT ACC_RAMP_STEP_SIZE_MIN |
| #define ACC_RAMP_STEP_SIZE_MAX 10 /* allow all ACC in one step (effectively disables ramping) */ |
| |
| #define ACC_RAMP_STEP_INTERVAL_MIN 30 /* 30 seconds */ |
| #define ACC_RAMP_STEP_INTERVAL_MAX 600 /* 10 minutes */ |
| |
| /*! |
| * Data structure used to manage ACC ramping. Please avoid setting or reading fields |
| * in this structure directly. Use the accessor functions below instead. |
| */ |
| struct acc_ramp { |
| struct gsm_bts *bts; /*!< backpointer to BTS using this ACC ramp */ |
| |
| bool acc_ramping_enabled; /*!< whether ACC ramping is enabled */ |
| |
| /*! |
| * Bitmask which keeps track of access control classes that are currently denied |
| * access. The function acc_ramp_apply() uses this mask to modulate bits from |
| * octets 2 and 3 in RACH Control Parameters (see 3GPP 44.018 10.5.2.29). |
| * Ramping is only concerned with ACCs 0-9. While any of the bits 0-9 is set, |
| * the corresponding ACC is barred. |
| * ACCs 11-15 should always be allowed, and ACC 10 denies emergency calls for |
| * all ACCs from 0-9 inclusive; these ACCs are ignored in this implementation. |
| */ |
| uint16_t barred_accs; |
| |
| /*! |
| * This controls the maximum number of ACCs to allow per ramping step (1 - 10). |
| * The compile-time default value is ACC_RAMP_STEP_SIZE_DEFAULT. |
| * This value can be changed by VTY configuration. |
| * A value of ACC_RAMP_STEP_SIZE_MAX effectively disables ramping. |
| */ |
| unsigned int step_size; |
| |
| /*! |
| * Ramping step interval in seconds. |
| * This value depends on the current BTS channel load average, unless |
| * it has been overriden by VTY configuration. |
| */ |
| unsigned int step_interval_sec; |
| bool step_interval_is_fixed; |
| struct osmo_timer_list step_timer; |
| }; |
| |
| /*! |
| * Return true if ACC ramping is currently enabled, else false. |
| * \param[in] acc_ramp Pointer to acc_ramp structure. |
| */ |
| static inline bool acc_ramp_is_enabled(struct acc_ramp *acc_ramp) |
| { |
| return acc_ramp->acc_ramping_enabled; |
| } |
| |
| /*! |
| * Return the current ACC ramp step size. |
| * \param[in] acc_ramp Pointer to acc_ramp structure. |
| */ |
| static inline unsigned int acc_ramp_get_step_size(struct acc_ramp *acc_ramp) |
| { |
| return acc_ramp->step_size; |
| } |
| |
| /*! |
| * Return the current ACC ramp step interval (in seconds) |
| * \param[in] acc_ramp Pointer to acc_ramp structure. |
| */ |
| static inline unsigned int acc_ramp_get_step_interval(struct acc_ramp *acc_ramp) |
| { |
| return acc_ramp->step_interval_sec; |
| } |
| |
| /*! |
| * If the step interval is dynamic, return true, else return false. |
| * \param[in] acc_ramp Pointer to acc_ramp structure. |
| */ |
| static inline bool acc_ramp_step_interval_is_dynamic(struct acc_ramp *acc_ramp) |
| { |
| return !(acc_ramp->step_interval_is_fixed); |
| } |
| |
| /*! |
| * Return bitmasks which correspond to access control classes that are currently |
| * denied access. Ramping is only concerned with those bits which control access |
| * for ACCs 0-9, and any of the other bits will always be set to zero in these masks, i.e. |
| * it is safe to OR these bitmasks with the corresponding fields in struct gsm48_rach_control. |
| * \param[in] acc_ramp Pointer to acc_ramp structure. |
| */ |
| static inline uint8_t acc_ramp_get_barred_t2(struct acc_ramp *acc_ramp) |
| { |
| return ((acc_ramp->barred_accs >> 8) & 0x03); |
| }; |
| static inline uint8_t acc_ramp_get_barred_t3(struct acc_ramp *acc_ramp) |
| { |
| return (acc_ramp->barred_accs & 0xff); |
| } |
| |
| /*! |
| * Potentially mark certain Access Control Classes (ACCs) as barred in accordance to ACC ramping. |
| * \param[in] rach_control RACH control parameters in which barred ACCs will be configured. |
| * \param[in] acc_ramp Pointer to acc_ramp structure. |
| */ |
| static inline void acc_ramp_apply(struct gsm48_rach_control *rach_control, struct acc_ramp *acc_ramp) |
| { |
| rach_control->t2 |= acc_ramp_get_barred_t2(acc_ramp); |
| rach_control->t3 |= acc_ramp_get_barred_t3(acc_ramp); |
| } |
| |
| void acc_ramp_init(struct acc_ramp *acc_ramp, bool enable, struct gsm_bts *bts); |
| int acc_ramp_set_step_size(struct acc_ramp *acc_ramp, unsigned int step_size); |
| int acc_ramp_set_step_interval(struct acc_ramp *acc_ramp, unsigned int step_interval); |
| void acc_ramp_set_step_interval_dynamic(struct acc_ramp *acc_ramp); |
| void acc_ramp_start(struct acc_ramp *acc_ramp); |
| void acc_ramp_abort(struct acc_ramp *acc_ramp); |