| /* Paging helper and manager.... */ |
| /* (C) 2009 by Holger Hans Peter Freyther <zecke@selfish.org> |
| * All Rights Reserved |
| * |
| * 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., |
| * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| */ |
| |
| /* |
| * Relevant specs: |
| * 12.21: |
| * - 9.4.12 for CCCH Local Threshold |
| * |
| * 05.58: |
| * - 8.5.2 CCCH Load indication |
| * - 9.3.15 Paging Load |
| * |
| * Approach: |
| * - Send paging command to subscriber |
| * - On Channel Request we will remember the reason |
| * - After the ACK we will request the identity |
| * - Then we will send assign the gsm_subscriber and |
| * - and call a callback |
| */ |
| |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <assert.h> |
| |
| #include <openbsc/paging.h> |
| #include <osmocore/talloc.h> |
| #include <openbsc/debug.h> |
| #include <openbsc/signal.h> |
| #include <openbsc/abis_rsl.h> |
| #include <openbsc/gsm_data.h> |
| |
| void *tall_paging_ctx; |
| |
| static unsigned int calculate_group(struct gsm_bts *bts, struct gsm_subscriber *subscr) |
| { |
| int ccch_conf; |
| int bs_cc_chans; |
| int blocks; |
| unsigned int group; |
| |
| ccch_conf = bts->si_common.chan_desc.ccch_conf; |
| bs_cc_chans = rsl_ccch_conf_to_bs_cc_chans(ccch_conf); |
| /* code word + 2, as 2 channels equals 0x0 */ |
| blocks = rsl_number_of_paging_subchannels(bts); |
| group = get_paging_group(str_to_imsi(subscr->imsi), |
| bs_cc_chans, blocks); |
| return group; |
| } |
| |
| /* |
| * Kill one paging request update the internal list... |
| */ |
| static void paging_remove_request(struct gsm_bts_paging_state *paging_bts, |
| struct gsm_paging_request *to_be_deleted) |
| { |
| /* Update the last_request if that is necessary */ |
| if (to_be_deleted == paging_bts->last_request) { |
| paging_bts->last_request = |
| (struct gsm_paging_request *)paging_bts->last_request->entry.next; |
| if (&to_be_deleted->entry == &paging_bts->pending_requests) |
| paging_bts->last_request = NULL; |
| } |
| |
| bsc_del_timer(&to_be_deleted->T3113); |
| llist_del(&to_be_deleted->entry); |
| subscr_put(to_be_deleted->subscr); |
| talloc_free(to_be_deleted); |
| } |
| |
| static void page_ms(struct gsm_paging_request *request) |
| { |
| u_int8_t mi[128]; |
| unsigned int mi_len; |
| unsigned int page_group; |
| |
| DEBUGP(DPAG, "Going to send paging commands: imsi: '%s' tmsi: '0x%x'\n", |
| request->subscr->imsi, request->subscr->tmsi); |
| |
| if (request->subscr->tmsi == GSM_RESERVED_TMSI) |
| mi_len = gsm48_generate_mid_from_imsi(mi, request->subscr->imsi); |
| else |
| mi_len = gsm48_generate_mid_from_tmsi(mi, request->subscr->tmsi); |
| |
| page_group = calculate_group(request->bts, request->subscr); |
| rsl_paging_cmd(request->bts, page_group, mi_len, mi, |
| request->chan_type); |
| } |
| |
| static void paging_move_to_next(struct gsm_bts_paging_state *paging_bts) |
| { |
| paging_bts->last_request = |
| (struct gsm_paging_request *)paging_bts->last_request->entry.next; |
| if (&paging_bts->last_request->entry == &paging_bts->pending_requests) |
| paging_bts->last_request = NULL; |
| } |
| |
| /* |
| * This is kicked by the periodic PAGING LOAD Indicator |
| * coming from abis_rsl.c |
| * |
| * We attempt to iterate once over the list of items but |
| * only upto available_slots. |
| */ |
| static void paging_handle_pending_requests(struct gsm_bts_paging_state *paging_bts) |
| { |
| struct gsm_paging_request *initial_request = NULL; |
| struct gsm_paging_request *current_request = NULL; |
| |
| /* |
| * Determine if the pending_requests list is empty and |
| * return then. |
| */ |
| if (llist_empty(&paging_bts->pending_requests)) { |
| paging_bts->last_request = NULL; |
| /* since the list is empty, no need to reschedule the timer */ |
| return; |
| } |
| |
| if (!paging_bts->last_request) |
| paging_bts->last_request = |
| (struct gsm_paging_request *)paging_bts->pending_requests.next; |
| |
| assert(paging_bts->last_request); |
| initial_request = paging_bts->last_request; |
| current_request = initial_request; |
| |
| do { |
| /* handle the paging request now */ |
| page_ms(current_request); |
| paging_bts->available_slots--; |
| |
| /* |
| * move to the next item. We might wrap around |
| * this means last_request will be NULL and we just |
| * call paging_page_to_next again. It it guranteed |
| * that the list is not empty. |
| */ |
| paging_move_to_next(paging_bts); |
| if (!paging_bts->last_request) |
| paging_bts->last_request = |
| (struct gsm_paging_request *)paging_bts->pending_requests.next; |
| current_request = paging_bts->last_request; |
| } while (paging_bts->available_slots > 0 |
| && initial_request != current_request); |
| |
| bsc_schedule_timer(&paging_bts->work_timer, 1, 0); |
| } |
| |
| static void paging_worker(void *data) |
| { |
| struct gsm_bts_paging_state *paging_bts = data; |
| |
| paging_handle_pending_requests(paging_bts); |
| } |
| |
| void paging_init(struct gsm_bts *bts) |
| { |
| bts->paging.bts = bts; |
| INIT_LLIST_HEAD(&bts->paging.pending_requests); |
| bts->paging.work_timer.cb = paging_worker; |
| bts->paging.work_timer.data = &bts->paging; |
| |
| /* Large number, until we get a proper message */ |
| bts->paging.available_slots = 100; |
| } |
| |
| static int paging_pending_request(struct gsm_bts_paging_state *bts, |
| struct gsm_subscriber *subscr) { |
| struct gsm_paging_request *req; |
| |
| llist_for_each_entry(req, &bts->pending_requests, entry) { |
| if (subscr == req->subscr) |
| return 1; |
| } |
| |
| return 0; |
| } |
| |
| static void paging_T3113_expired(void *data) |
| { |
| struct gsm_paging_request *req = (struct gsm_paging_request *)data; |
| struct paging_signal_data sig_data; |
| void *cbfn_param; |
| gsm_cbfn *cbfn; |
| |
| DEBUGP(DPAG, "T3113 expired for request %p (%s)\n", |
| req, req->subscr->imsi); |
| |
| sig_data.subscr = req->subscr; |
| sig_data.bts = req->bts; |
| sig_data.lchan = NULL; |
| |
| /* must be destroyed before calling cbfn, to prevent double free */ |
| cbfn_param = req->cbfn_param; |
| cbfn = req->cbfn; |
| paging_remove_request(&req->bts->paging, req); |
| |
| counter_inc(req->bts->network->stats.paging.expired); |
| |
| dispatch_signal(SS_PAGING, S_PAGING_EXPIRED, &sig_data); |
| if (cbfn) |
| cbfn(GSM_HOOK_RR_PAGING, GSM_PAGING_EXPIRED, NULL, NULL, |
| cbfn_param); |
| } |
| |
| static int _paging_request(struct gsm_bts *bts, struct gsm_subscriber *subscr, |
| int type, gsm_cbfn *cbfn, void *data) |
| { |
| struct gsm_bts_paging_state *bts_entry = &bts->paging; |
| struct gsm_paging_request *req; |
| |
| if (paging_pending_request(bts_entry, subscr)) { |
| DEBUGP(DPAG, "Paging request already pending\n"); |
| return -EEXIST; |
| } |
| |
| DEBUGP(DPAG, "Start paging of subscriber %llu on bts %d.\n", |
| subscr->id, bts->nr); |
| req = talloc_zero(tall_paging_ctx, struct gsm_paging_request); |
| req->subscr = subscr_get(subscr); |
| req->bts = bts; |
| req->chan_type = type; |
| req->cbfn = cbfn; |
| req->cbfn_param = data; |
| req->T3113.cb = paging_T3113_expired; |
| req->T3113.data = req; |
| bsc_schedule_timer(&req->T3113, bts->network->T3113, 0); |
| llist_add_tail(&req->entry, &bts_entry->pending_requests); |
| |
| if (!bsc_timer_pending(&bts_entry->work_timer)) |
| bsc_schedule_timer(&bts_entry->work_timer, 1, 0); |
| |
| return 0; |
| } |
| |
| int paging_request(struct gsm_network *network, struct gsm_subscriber *subscr, |
| int type, gsm_cbfn *cbfn, void *data) |
| { |
| struct gsm_bts *bts = NULL; |
| int num_pages = 0; |
| |
| counter_inc(network->stats.paging.attempted); |
| |
| /* start paging subscriber on all BTS within Location Area */ |
| do { |
| int rc; |
| |
| bts = gsm_bts_by_lac(network, subscr->lac, bts); |
| if (!bts) |
| break; |
| |
| /* skip all currently inactive TRX */ |
| if (!trx_is_usable(bts->c0)) |
| continue; |
| |
| num_pages++; |
| |
| /* Trigger paging, pass any error to caller */ |
| rc = _paging_request(bts, subscr, type, cbfn, data); |
| if (rc < 0) |
| return rc; |
| } while (1); |
| |
| if (num_pages == 0) |
| counter_inc(network->stats.paging.detached); |
| |
| return num_pages; |
| } |
| |
| |
| /* we consciously ignore the type of the request here */ |
| static void _paging_request_stop(struct gsm_bts *bts, struct gsm_subscriber *subscr, |
| struct gsm_lchan *lchan) |
| { |
| struct gsm_bts_paging_state *bts_entry = &bts->paging; |
| struct gsm_paging_request *req, *req2; |
| |
| llist_for_each_entry_safe(req, req2, &bts_entry->pending_requests, |
| entry) { |
| if (req->subscr == subscr) { |
| if (lchan && req->cbfn) { |
| DEBUGP(DPAG, "Stop paging on bts %d, calling cbfn.\n", bts->nr); |
| req->cbfn(GSM_HOOK_RR_PAGING, GSM_PAGING_SUCCEEDED, |
| NULL, lchan, req->cbfn_param); |
| } else |
| DEBUGP(DPAG, "Stop paging on bts %d silently.\n", bts->nr); |
| paging_remove_request(&bts->paging, req); |
| break; |
| } |
| } |
| } |
| |
| /* Stop paging on all other bts' */ |
| void paging_request_stop(struct gsm_bts *_bts, struct gsm_subscriber *subscr, |
| struct gsm_lchan *lchan) |
| { |
| struct gsm_bts *bts = NULL; |
| |
| if (_bts) |
| _paging_request_stop(_bts, subscr, lchan); |
| |
| do { |
| /* |
| * FIXME: Don't use the lac of the subscriber... |
| * as it might have magically changed the lac.. use the |
| * location area of the _bts as reconfiguration of the |
| * network is probably happening less often. |
| */ |
| bts = gsm_bts_by_lac(subscr->net, subscr->lac, bts); |
| if (!bts) |
| break; |
| |
| /* Stop paging */ |
| if (bts != _bts) |
| _paging_request_stop(bts, subscr, NULL); |
| } while (1); |
| } |
| |
| void paging_update_buffer_space(struct gsm_bts *bts, u_int16_t free_slots) |
| { |
| bts->paging.available_slots = free_slots; |
| } |