diff options
Diffstat (limited to 'openbsc/src/paging.c')
-rw-r--r-- | openbsc/src/paging.c | 339 |
1 files changed, 339 insertions, 0 deletions
diff --git a/openbsc/src/paging.c b/openbsc/src/paging.c new file mode 100644 index 000000000..7c3750d66 --- /dev/null +++ b/openbsc/src/paging.c @@ -0,0 +1,339 @@ +/* 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; +} |