Stefan Sperling | 6442e43 | 2018-02-06 14:44:54 +0100 | [diff] [blame] | 1 | /* (C) 2018 by sysmocom s.f.m.c. GmbH <info@sysmocom.de> |
| 2 | * |
| 3 | * Author: Stefan Sperling <ssperling@sysmocom.de> |
| 4 | * |
| 5 | * All Rights Reserved |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU Affero General Public License as published by |
| 9 | * the Free Software Foundation; either version 3 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU Affero General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU Affero General Public License |
| 18 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 19 | * |
| 20 | */ |
| 21 | |
| 22 | #include <strings.h> |
| 23 | #include <errno.h> |
| 24 | #include <stdbool.h> |
| 25 | |
| 26 | #include <osmocom/bsc/debug.h> |
| 27 | #include <osmocom/bsc/acc_ramp.h> |
| 28 | #include <osmocom/bsc/gsm_data.h> |
| 29 | |
| 30 | /* |
| 31 | * Check if an ACC has been permanently barred for a BTS, |
| 32 | * e.g. with the 'rach access-control-class' VTY command. |
| 33 | */ |
| 34 | static bool acc_is_enabled(struct gsm_bts *bts, unsigned int acc) |
| 35 | { |
| 36 | OSMO_ASSERT(acc >= 0 && acc <= 9); |
| 37 | if (acc == 8 || acc == 9) |
| 38 | return (bts->si_common.rach_control.t2 & (1 << (acc - 8))) == 0; |
| 39 | return (bts->si_common.rach_control.t3 & (1 << (acc))) == 0; |
| 40 | } |
| 41 | |
| 42 | static void allow_one_acc(struct acc_ramp *acc_ramp, unsigned int acc) |
| 43 | { |
| 44 | OSMO_ASSERT(acc >= 0 && acc <= 9); |
| 45 | LOGP(DRSL, LOGL_DEBUG, "(bts=%d) ACC RAMP: allowing Access Control Class %u\n", acc_ramp->bts->nr, acc); |
| 46 | acc_ramp->barred_accs &= ~(1 << acc); |
| 47 | } |
| 48 | |
| 49 | static void barr_one_acc(struct acc_ramp *acc_ramp, unsigned int acc) |
| 50 | { |
| 51 | OSMO_ASSERT(acc >= 0 && acc <= 9); |
| 52 | LOGP(DRSL, LOGL_DEBUG, "(bts=%d) ACC RAMP: barring Access Control Class %u\n", acc_ramp->bts->nr, acc); |
| 53 | acc_ramp->barred_accs |= (1 << acc); |
| 54 | } |
| 55 | |
| 56 | static void barr_all_enabled_accs(struct acc_ramp *acc_ramp) |
| 57 | { |
| 58 | unsigned int acc; |
| 59 | for (acc = 0; acc < 10; acc++) { |
| 60 | if (acc_is_enabled(acc_ramp->bts, acc)) |
| 61 | barr_one_acc(acc_ramp, acc); |
| 62 | } |
| 63 | } |
| 64 | |
| 65 | static void allow_all_enabled_accs(struct acc_ramp *acc_ramp) |
| 66 | { |
| 67 | unsigned int acc; |
| 68 | for (acc = 0; acc < 10; acc++) { |
| 69 | if (acc_is_enabled(acc_ramp->bts, acc)) |
| 70 | allow_one_acc(acc_ramp, acc); |
| 71 | } |
| 72 | } |
| 73 | |
| 74 | static unsigned int get_next_step_interval(struct acc_ramp *acc_ramp) |
| 75 | { |
| 76 | struct gsm_bts *bts = acc_ramp->bts; |
| 77 | uint64_t load; |
| 78 | |
| 79 | if (acc_ramp->step_interval_is_fixed) |
| 80 | return acc_ramp->step_interval_sec; |
| 81 | |
| 82 | /* Scale the step interval to current channel load average. */ |
| 83 | load = (bts->chan_load_avg << 8); /* convert to fixed-point */ |
| 84 | acc_ramp->step_interval_sec = ((load * ACC_RAMP_STEP_INTERVAL_MAX) / 100) >> 8; |
| 85 | if (acc_ramp->step_interval_sec < ACC_RAMP_STEP_SIZE_MIN) |
| 86 | acc_ramp->step_interval_sec = ACC_RAMP_STEP_INTERVAL_MIN; |
| 87 | else if (acc_ramp->step_interval_sec > ACC_RAMP_STEP_INTERVAL_MAX) |
| 88 | acc_ramp->step_interval_sec = ACC_RAMP_STEP_INTERVAL_MAX; |
| 89 | |
| 90 | LOGP(DRSL, LOGL_DEBUG, "(bts=%d) ACC RAMP: step interval set to %u seconds based on %u%% channel load average\n", |
| 91 | bts->nr, acc_ramp->step_interval_sec, bts->chan_load_avg); |
| 92 | return acc_ramp->step_interval_sec; |
| 93 | } |
| 94 | |
| 95 | static void do_acc_ramping_step(void *data) |
| 96 | { |
| 97 | struct acc_ramp *acc_ramp = data; |
| 98 | int i; |
| 99 | |
| 100 | /* Shortcut in case we only do one ramping step. */ |
| 101 | if (acc_ramp->step_size == ACC_RAMP_STEP_SIZE_MAX) { |
| 102 | allow_all_enabled_accs(acc_ramp); |
| 103 | gsm_bts_set_system_infos(acc_ramp->bts); |
| 104 | return; |
| 105 | } |
| 106 | |
| 107 | /* Allow 'step_size' ACCs, starting from ACC0. ACC9 will be allowed last. */ |
| 108 | for (i = 0; i < acc_ramp->step_size; i++) { |
| 109 | int idx = ffs(acc_ramp_get_barred_t3(acc_ramp)); |
| 110 | if (idx > 0) { |
| 111 | /* One of ACC0-ACC7 is still bared. */ |
| 112 | unsigned int acc = idx - 1; |
| 113 | if (acc_is_enabled(acc_ramp->bts, acc)) |
| 114 | allow_one_acc(acc_ramp, acc); |
| 115 | } else { |
| 116 | idx = ffs(acc_ramp_get_barred_t2(acc_ramp)); |
| 117 | if (idx == 1 || idx == 2) { |
| 118 | /* ACC8 or ACC9 is still barred. */ |
| 119 | unsigned int acc = idx - 1 + 8; |
| 120 | if (acc_is_enabled(acc_ramp->bts, acc)) |
| 121 | allow_one_acc(acc_ramp, acc); |
| 122 | } else { |
| 123 | /* All ACCs are now allowed. */ |
| 124 | break; |
| 125 | } |
| 126 | } |
| 127 | } |
| 128 | |
| 129 | gsm_bts_set_system_infos(acc_ramp->bts); |
| 130 | |
| 131 | /* If we have not allowed all ACCs yet, schedule another ramping step. */ |
| 132 | if (acc_ramp_get_barred_t2(acc_ramp) != 0x00 || |
| 133 | acc_ramp_get_barred_t3(acc_ramp) != 0x00) |
| 134 | osmo_timer_schedule(&acc_ramp->step_timer, get_next_step_interval(acc_ramp), 0); |
| 135 | } |
| 136 | |
| 137 | /*! |
| 138 | * Initialize an acc_ramp data structure. |
| 139 | * Storage for this structure must be provided by the caller. |
| 140 | * |
| 141 | * If ACC ramping is enabled, all ACCs are denied by default. |
| 142 | * A subsequent call to acc_ramp_start() will begin the ramping process. |
| 143 | * If ACC ramping is disabled, all ACCs will be allowed by default, |
| 144 | * and there is no need to do anything else. |
| 145 | * |
| 146 | * \param[in] acc_ramp Pointer to acc_ramp structure to be initialized. |
| 147 | * \param[in] enable Indicates whether ACC ramping should be enabled or disabled. |
| 148 | * \param[in] bts BTS which uses this ACC ramp data structure. |
| 149 | */ |
| 150 | void acc_ramp_init(struct acc_ramp *acc_ramp, bool enable, struct gsm_bts *bts) |
| 151 | { |
| 152 | acc_ramp->bts = bts; |
| 153 | acc_ramp->acc_ramping_enabled = enable; |
| 154 | acc_ramp->step_size = ACC_RAMP_STEP_SIZE_DEFAULT; |
| 155 | acc_ramp->step_interval_sec = ACC_RAMP_STEP_INTERVAL_MIN; |
| 156 | acc_ramp->step_interval_is_fixed = false; |
| 157 | osmo_timer_setup(&acc_ramp->step_timer, do_acc_ramping_step, acc_ramp); |
| 158 | |
| 159 | if (acc_ramp->acc_ramping_enabled) |
| 160 | barr_all_enabled_accs(acc_ramp); |
| 161 | else |
| 162 | allow_all_enabled_accs(acc_ramp); |
| 163 | } |
| 164 | |
| 165 | /*! |
| 166 | * Change the ramping step size which controls how many ACCs will be allowed per ramping step. |
| 167 | * Returns negative on error (step_size out of range), else zero. |
| 168 | * \param[in] acc_ramp Pointer to acc_ramp structure. |
| 169 | * \param[in] step_size The new step size value. |
| 170 | */ |
| 171 | int acc_ramp_set_step_size(struct acc_ramp *acc_ramp, unsigned int step_size) |
| 172 | { |
| 173 | if (step_size < ACC_RAMP_STEP_SIZE_MIN || step_size > ACC_RAMP_STEP_SIZE_MAX) |
| 174 | return -ERANGE; |
| 175 | |
| 176 | acc_ramp->step_size = step_size; |
| 177 | LOGP(DRSL, LOGL_DEBUG, "(bts=%d) ACC RAMP: ramping step size set to %u\n", acc_ramp->bts->nr, step_size); |
| 178 | return 0; |
| 179 | } |
| 180 | |
| 181 | /*! |
| 182 | * Change the ramping step interval to a fixed value. Unless this function is called, |
| 183 | * the interval is automatically scaled to the BTS channel load average. |
| 184 | * \param[in] acc_ramp Pointer to acc_ramp structure. |
| 185 | * \param[in] step_interval The new fixed step interval in seconds. |
| 186 | */ |
| 187 | int acc_ramp_set_step_interval(struct acc_ramp *acc_ramp, unsigned int step_interval) |
| 188 | { |
| 189 | if (step_interval < ACC_RAMP_STEP_INTERVAL_MIN || step_interval > ACC_RAMP_STEP_INTERVAL_MAX) |
| 190 | return -ERANGE; |
| 191 | |
| 192 | acc_ramp->step_interval_sec = step_interval; |
| 193 | acc_ramp->step_interval_is_fixed = true; |
| 194 | LOGP(DRSL, LOGL_DEBUG, "(bts=%d) ACC RAMP: ramping step interval set to %u seconds\n", |
| 195 | acc_ramp->bts->nr, step_interval); |
| 196 | return 0; |
| 197 | } |
| 198 | |
| 199 | /*! |
| 200 | * Clear a previously set fixed ramping step interval, so that the interval |
| 201 | * is again automatically scaled to the BTS channel load average. |
| 202 | * \param[in] acc_ramp Pointer to acc_ramp structure. |
| 203 | */ |
| 204 | void acc_ramp_set_step_interval_dynamic(struct acc_ramp *acc_ramp) |
| 205 | { |
| 206 | acc_ramp->step_interval_is_fixed = false; |
| 207 | LOGP(DRSL, LOGL_DEBUG, "(bts=%d) ACC RAMP: ramping step interval set to 'dynamic'\n", |
| 208 | acc_ramp->bts->nr); |
| 209 | } |
| 210 | |
| 211 | /*! |
| 212 | * Begin the ramping process. Perform at least one ramping step to allow 'step_size' ACCs. |
| 213 | * If 'step_size' is ACC_RAMP_STEP_SIZE_MAX, all ACCs will be allowed immediately. |
| 214 | * \param[in] acc_ramp Pointer to acc_ramp structure. |
| 215 | */ |
| 216 | void acc_ramp_start(struct acc_ramp *acc_ramp) |
| 217 | { |
| 218 | /* Abort any previously running ramping process. */ |
| 219 | acc_ramp_abort(acc_ramp); |
| 220 | |
| 221 | /* Set all availble ACCs to barred and start ramping up. */ |
| 222 | barr_all_enabled_accs(acc_ramp); |
| 223 | do_acc_ramping_step(acc_ramp); |
| 224 | } |
| 225 | |
| 226 | /*! |
| 227 | * Abort the ramping process. If ramping is disabled or has already finished, |
| 228 | * then this function has no effect. |
| 229 | * \param[in] acc_ramp Pointer to acc_ramp structure. |
| 230 | */ |
| 231 | void acc_ramp_abort(struct acc_ramp *acc_ramp) |
| 232 | { |
| 233 | if (osmo_timer_pending(&acc_ramp->step_timer)) |
| 234 | osmo_timer_del(&acc_ramp->step_timer); |
| 235 | } |