396 lines
11 KiB
C
396 lines
11 KiB
C
/* Paging helper and manager.... */
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/* (C) 2009 by Holger Hans Peter Freyther <zecke@selfish.org>
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* All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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/*
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* Relevant specs:
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* 12.21:
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* - 9.4.12 for CCCH Local Threshold
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*
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* 05.58:
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* - 8.5.2 CCCH Load indication
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* - 9.3.15 Paging Load
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*
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* Approach:
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* - Send paging command to subscriber
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* - On Channel Request we will remember the reason
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* - After the ACK we will request the identity
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* - Then we will send assign the gsm_subscriber and
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* - and call a callback
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <assert.h>
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#include <openbsc/paging.h>
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#include <osmocore/talloc.h>
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#include <openbsc/debug.h>
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#include <openbsc/signal.h>
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#include <openbsc/abis_rsl.h>
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#include <openbsc/gsm_data.h>
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#include <openbsc/chan_alloc.h>
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#include <openbsc/bsc_api.h>
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void *tall_paging_ctx;
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#define PAGING_TIMER 0, 500000
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static unsigned int calculate_group(struct gsm_bts *bts, struct gsm_subscriber *subscr)
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{
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int ccch_conf;
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int bs_cc_chans;
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int blocks;
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unsigned int group;
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ccch_conf = bts->si_common.chan_desc.ccch_conf;
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bs_cc_chans = rsl_ccch_conf_to_bs_cc_chans(ccch_conf);
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/* code word + 2, as 2 channels equals 0x0 */
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blocks = rsl_number_of_paging_subchannels(bts);
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group = get_paging_group(str_to_imsi(subscr->imsi),
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bs_cc_chans, blocks);
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return group;
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}
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/*
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* Kill one paging request update the internal list...
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*/
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static void paging_remove_request(struct gsm_bts_paging_state *paging_bts,
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struct gsm_paging_request *to_be_deleted)
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{
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bsc_del_timer(&to_be_deleted->T3113);
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llist_del(&to_be_deleted->entry);
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subscr_put(to_be_deleted->subscr);
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talloc_free(to_be_deleted);
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}
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static void page_ms(struct gsm_paging_request *request)
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{
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u_int8_t mi[128];
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unsigned int mi_len;
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unsigned int page_group;
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LOGP(DPAG, LOGL_INFO, "Going to send paging commands: imsi: '%s' tmsi: '0x%x'\n",
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request->subscr->imsi, request->subscr->tmsi);
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if (request->subscr->tmsi == GSM_RESERVED_TMSI)
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mi_len = gsm48_generate_mid_from_imsi(mi, request->subscr->imsi);
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else
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mi_len = gsm48_generate_mid_from_tmsi(mi, request->subscr->tmsi);
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page_group = calculate_group(request->bts, request->subscr);
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gsm0808_page(request->bts, page_group, mi_len, mi, request->chan_type);
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}
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static void paging_schedule_if_needed(struct gsm_bts_paging_state *paging_bts)
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{
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if (llist_empty(&paging_bts->pending_requests))
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return;
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if (!bsc_timer_pending(&paging_bts->work_timer))
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bsc_schedule_timer(&paging_bts->work_timer, PAGING_TIMER);
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}
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static void paging_handle_pending_requests(struct gsm_bts_paging_state *paging_bts);
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static void paging_give_credit(void *data)
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{
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struct gsm_bts_paging_state *paging_bts = data;
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LOGP(DPAG, LOGL_NOTICE, "No slots available on bts nr %d\n", paging_bts->bts->nr);
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paging_bts->available_slots = 20;
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paging_handle_pending_requests(paging_bts);
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}
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static int can_send_pag_req(struct gsm_bts *bts, int rsl_type)
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{
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struct pchan_load pl;
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int count;
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memset(&pl, 0, sizeof(pl));
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bts_chan_load(&pl, bts);
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switch (rsl_type) {
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case RSL_CHANNEED_TCH_F:
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case RSL_CHANNEED_TCH_ForH:
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goto count_tch;
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break;
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case RSL_CHANNEED_SDCCH:
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goto count_sdcch;
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break;
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case RSL_CHANNEED_ANY:
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default:
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if (bts->network->pag_any_tch)
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goto count_tch;
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else
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goto count_sdcch;
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break;
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}
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return 0;
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/* could available SDCCH */
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count_sdcch:
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count = 0;
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count += pl.pchan[GSM_PCHAN_SDCCH8_SACCH8C].total
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- pl.pchan[GSM_PCHAN_SDCCH8_SACCH8C].used;
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count += pl.pchan[GSM_PCHAN_CCCH_SDCCH4].total
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- pl.pchan[GSM_PCHAN_CCCH_SDCCH4].used;
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return bts->paging.free_chans_need > count;
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count_tch:
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count = 0;
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count += pl.pchan[GSM_PCHAN_TCH_F].total
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- pl.pchan[GSM_PCHAN_TCH_F].used;
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if (bts->network->neci)
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count += pl.pchan[GSM_PCHAN_TCH_H].total
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- pl.pchan[GSM_PCHAN_TCH_H].used;
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return bts->paging.free_chans_need > count;
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}
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/*
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* This is kicked by the periodic PAGING LOAD Indicator
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* coming from abis_rsl.c
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*
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* We attempt to iterate once over the list of items but
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* only upto available_slots.
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*/
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static void paging_handle_pending_requests(struct gsm_bts_paging_state *paging_bts)
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{
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struct gsm_paging_request *request = NULL;
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/*
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* Determine if the pending_requests list is empty and
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* return then.
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*/
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if (llist_empty(&paging_bts->pending_requests)) {
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/* since the list is empty, no need to reschedule the timer */
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return;
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}
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/*
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* In case the BTS does not provide us with load indication and we
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* ran out of slots, call an autofill routine. It might be that the
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* BTS did not like our paging messages and then we have counted down
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* to zero and we do not get any messages.
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*/
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if (paging_bts->available_slots == 0) {
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paging_bts->credit_timer.cb = paging_give_credit;
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paging_bts->credit_timer.data = paging_bts;
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bsc_schedule_timer(&paging_bts->credit_timer, 5, 0);
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return;
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}
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request = llist_entry(paging_bts->pending_requests.next,
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struct gsm_paging_request, entry);
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/* we need to determine the number of free channels */
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if (paging_bts->free_chans_need != -1) {
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if (can_send_pag_req(request->bts, request->chan_type) != 0)
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goto skip_paging;
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}
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/* handle the paging request now */
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page_ms(request);
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paging_bts->available_slots--;
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request->attempts++;
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/* take the current and add it to the back */
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llist_del(&request->entry);
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llist_add_tail(&request->entry, &paging_bts->pending_requests);
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skip_paging:
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bsc_schedule_timer(&paging_bts->work_timer, PAGING_TIMER);
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}
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static void paging_worker(void *data)
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{
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struct gsm_bts_paging_state *paging_bts = data;
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paging_handle_pending_requests(paging_bts);
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}
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void paging_init(struct gsm_bts *bts)
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{
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bts->paging.bts = bts;
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INIT_LLIST_HEAD(&bts->paging.pending_requests);
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bts->paging.work_timer.cb = paging_worker;
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bts->paging.work_timer.data = &bts->paging;
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/* Large number, until we get a proper message */
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bts->paging.available_slots = 20;
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}
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static int paging_pending_request(struct gsm_bts_paging_state *bts,
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struct gsm_subscriber *subscr) {
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struct gsm_paging_request *req;
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llist_for_each_entry(req, &bts->pending_requests, entry) {
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if (subscr == req->subscr)
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return 1;
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}
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return 0;
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}
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static void paging_T3113_expired(void *data)
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{
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struct gsm_paging_request *req = (struct gsm_paging_request *)data;
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void *cbfn_param;
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gsm_cbfn *cbfn;
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int msg;
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LOGP(DPAG, LOGL_INFO, "T3113 expired for request %p (%s)\n",
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req, req->subscr->imsi);
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/* must be destroyed before calling cbfn, to prevent double free */
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counter_inc(req->bts->network->stats.paging.expired);
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cbfn_param = req->cbfn_param;
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cbfn = req->cbfn;
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/* did we ever manage to page the subscriber */
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msg = req->attempts > 0 ? GSM_PAGING_EXPIRED : GSM_PAGING_BUSY;
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/* destroy it now. Do not access req afterwards */
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paging_remove_request(&req->bts->paging, req);
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if (cbfn)
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cbfn(GSM_HOOK_RR_PAGING, msg, NULL, NULL,
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cbfn_param);
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}
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static int _paging_request(struct gsm_bts *bts, struct gsm_subscriber *subscr,
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int type, gsm_cbfn *cbfn, void *data)
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{
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struct gsm_bts_paging_state *bts_entry = &bts->paging;
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struct gsm_paging_request *req;
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if (paging_pending_request(bts_entry, subscr)) {
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LOGP(DPAG, LOGL_INFO, "Paging request already pending for %s\n", subscr->imsi);
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return -EEXIST;
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}
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LOGP(DPAG, LOGL_DEBUG, "Start paging of subscriber %llu on bts %d.\n",
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subscr->id, bts->nr);
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req = talloc_zero(tall_paging_ctx, struct gsm_paging_request);
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req->subscr = subscr_get(subscr);
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req->bts = bts;
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req->chan_type = type;
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req->cbfn = cbfn;
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req->cbfn_param = data;
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req->T3113.cb = paging_T3113_expired;
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req->T3113.data = req;
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bsc_schedule_timer(&req->T3113, bts->network->T3113, 0);
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llist_add_tail(&req->entry, &bts_entry->pending_requests);
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paging_schedule_if_needed(bts_entry);
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return 0;
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}
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int paging_request(struct gsm_network *network, struct gsm_subscriber *subscr,
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int type, gsm_cbfn *cbfn, void *data)
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{
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struct gsm_bts *bts = NULL;
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int num_pages = 0;
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counter_inc(network->stats.paging.attempted);
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/* start paging subscriber on all BTS within Location Area */
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do {
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int rc;
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bts = gsm_bts_by_lac(network, subscr->lac, bts);
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if (!bts)
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break;
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/* skip all currently inactive TRX */
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if (!trx_is_usable(bts->c0))
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continue;
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num_pages++;
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/* Trigger paging, pass any error to caller */
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rc = _paging_request(bts, subscr, type, cbfn, data);
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if (rc < 0)
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return rc;
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} while (1);
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if (num_pages == 0)
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counter_inc(network->stats.paging.detached);
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return num_pages;
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}
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/* we consciously ignore the type of the request here */
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static void _paging_request_stop(struct gsm_bts *bts, struct gsm_subscriber *subscr,
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struct gsm_subscriber_connection *conn,
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struct msgb *msg)
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{
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struct gsm_bts_paging_state *bts_entry = &bts->paging;
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struct gsm_paging_request *req, *req2;
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llist_for_each_entry_safe(req, req2, &bts_entry->pending_requests,
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entry) {
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if (req->subscr == subscr) {
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if (conn && req->cbfn) {
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LOGP(DPAG, LOGL_DEBUG, "Stop paging on bts %d, calling cbfn.\n", bts->nr);
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req->cbfn(GSM_HOOK_RR_PAGING, GSM_PAGING_SUCCEEDED,
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msg, conn, req->cbfn_param);
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} else
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LOGP(DPAG, LOGL_DEBUG, "Stop paging on bts %d silently.\n", bts->nr);
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paging_remove_request(&bts->paging, req);
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break;
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}
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}
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}
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/* Stop paging on all other bts' */
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void paging_request_stop(struct gsm_bts *_bts, struct gsm_subscriber *subscr,
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struct gsm_subscriber_connection *conn,
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struct msgb *msg)
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{
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struct gsm_bts *bts = NULL;
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if (_bts)
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_paging_request_stop(_bts, subscr, conn, msg);
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do {
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/*
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* FIXME: Don't use the lac of the subscriber...
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* as it might have magically changed the lac.. use the
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* location area of the _bts as reconfiguration of the
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* network is probably happening less often.
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*/
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bts = gsm_bts_by_lac(subscr->net, subscr->lac, bts);
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if (!bts)
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break;
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/* Stop paging */
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if (bts != _bts)
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_paging_request_stop(bts, subscr, NULL, NULL);
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} while (1);
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}
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void paging_update_buffer_space(struct gsm_bts *bts, u_int16_t free_slots)
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{
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bsc_del_timer(&bts->paging.credit_timer);
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bts->paging.available_slots = free_slots;
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paging_schedule_if_needed(&bts->paging);
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}
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