| /* Paging helper and manager.... */ |
| /* (C) 2009,2013 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 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/>. |
| * |
| */ |
| |
| /* |
| * 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 <osmocom/core/talloc.h> |
| #include <osmocom/core/tdef.h> |
| #include <osmocom/gsm/gsm48.h> |
| #include <osmocom/gsm/gsm0502.h> |
| |
| #include <osmocom/bsc/bsc_subscriber.h> |
| #include <osmocom/bsc/paging.h> |
| #include <osmocom/bsc/debug.h> |
| #include <osmocom/bsc/signal.h> |
| #include <osmocom/bsc/abis_rsl.h> |
| #include <osmocom/bsc/gsm_data.h> |
| #include <osmocom/bsc/chan_alloc.h> |
| #include <osmocom/bsc/gsm_08_08.h> |
| #include <osmocom/bsc/gsm_04_08_rr.h> |
| #include <osmocom/bsc/bsc_subscr_conn_fsm.h> |
| #include <osmocom/bsc/bts.h> |
| |
| void *tall_paging_ctx = NULL; |
| |
| #define PAGING_TIMER 0, 500000 |
| |
| /* |
| * 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) |
| { |
| osmo_timer_del(&to_be_deleted->T3113); |
| llist_del(&to_be_deleted->entry); |
| bsc_subscr_put(to_be_deleted->bsub); |
| talloc_free(to_be_deleted); |
| } |
| |
| static void page_ms(struct gsm_paging_request *request) |
| { |
| unsigned int page_group; |
| struct gsm_bts *bts = request->bts; |
| struct osmo_mobile_identity mi; |
| |
| log_set_context(LOG_CTX_BSC_SUBSCR, request->bsub); |
| |
| LOG_BTS(bts, DPAG, LOGL_INFO, "Going to send paging commands: imsi: %s tmsi: " |
| "0x%08x for ch. type %d (attempt %d)\n", request->bsub->imsi, |
| request->bsub->tmsi, request->chan_type, request->attempts); |
| |
| if (request->bsub->tmsi == GSM_RESERVED_TMSI) { |
| mi = (struct osmo_mobile_identity){ |
| .type = GSM_MI_TYPE_IMSI, |
| }; |
| OSMO_STRLCPY_ARRAY(mi.imsi, request->bsub->imsi); |
| } else { |
| mi = (struct osmo_mobile_identity){ |
| .type = GSM_MI_TYPE_TMSI, |
| .tmsi = request->bsub->tmsi, |
| }; |
| } |
| |
| page_group = gsm0502_calc_paging_group(&bts->si_common.chan_desc, |
| str_to_imsi(request->bsub->imsi)); |
| rsl_paging_cmd(bts, page_group, &mi, request->chan_type, false); |
| log_set_context(LOG_CTX_BSC_SUBSCR, NULL); |
| } |
| |
| static void paging_schedule_if_needed(struct gsm_bts_paging_state *paging_bts) |
| { |
| if (llist_empty(&paging_bts->pending_requests)) |
| return; |
| |
| if (!osmo_timer_pending(&paging_bts->work_timer)) |
| osmo_timer_schedule(&paging_bts->work_timer, PAGING_TIMER); |
| } |
| |
| |
| static void paging_handle_pending_requests(struct gsm_bts_paging_state *paging_bts); |
| static void paging_give_credit(void *data) |
| { |
| struct gsm_bts_paging_state *paging_bts = data; |
| |
| LOG_BTS(paging_bts->bts, DPAG, LOGL_NOTICE, "No PCH LOAD IND, adding 20 slots)\n"); |
| paging_bts->available_slots = 20; |
| paging_handle_pending_requests(paging_bts); |
| } |
| |
| /*! count the number of free channels for given RSL channel type required |
| * \param[in] BTS on which we shall count |
| * \param[in] rsl_type the RSL channel needed type |
| * \returns number of free channels matching \a rsl_type in \a bts */ |
| static int can_send_pag_req(struct gsm_bts *bts, int rsl_type) |
| { |
| struct pchan_load pl; |
| int count; |
| |
| memset(&pl, 0, sizeof(pl)); |
| bts_chan_load(&pl, bts); |
| |
| switch (rsl_type) { |
| case RSL_CHANNEED_TCH_F: |
| case RSL_CHANNEED_TCH_ForH: |
| goto count_tch; |
| break; |
| case RSL_CHANNEED_SDCCH: |
| goto count_sdcch; |
| break; |
| case RSL_CHANNEED_ANY: |
| default: |
| if (bts->network->pag_any_tch) |
| goto count_tch; |
| else |
| goto count_sdcch; |
| break; |
| } |
| |
| return 0; |
| |
| /* could available SDCCH */ |
| count_sdcch: |
| count = 0; |
| count += pl.pchan[GSM_PCHAN_SDCCH8_SACCH8C].total |
| - pl.pchan[GSM_PCHAN_SDCCH8_SACCH8C].used; |
| count += pl.pchan[GSM_PCHAN_CCCH_SDCCH4].total |
| - pl.pchan[GSM_PCHAN_CCCH_SDCCH4].used; |
| return bts->paging.free_chans_need > count; |
| |
| count_tch: |
| count = 0; |
| count += pl.pchan[GSM_PCHAN_TCH_F].total |
| - pl.pchan[GSM_PCHAN_TCH_F].used; |
| if (bts->network->neci) |
| count += pl.pchan[GSM_PCHAN_TCH_H].total |
| - pl.pchan[GSM_PCHAN_TCH_H].used; |
| return bts->paging.free_chans_need > count; |
| } |
| |
| /* |
| * 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 *request = NULL; |
| |
| /* |
| * Determine if the pending_requests list is empty and |
| * return then. |
| */ |
| if (llist_empty(&paging_bts->pending_requests)) { |
| /* since the list is empty, no need to reschedule the timer */ |
| return; |
| } |
| |
| /* |
| * In case the BTS does not provide us with load indication and we |
| * ran out of slots, call an autofill routine. It might be that the |
| * BTS did not like our paging messages and then we have counted down |
| * to zero and we do not get any messages. |
| */ |
| if (paging_bts->available_slots == 0) { |
| osmo_timer_setup(&paging_bts->credit_timer, paging_give_credit, |
| paging_bts); |
| osmo_timer_schedule(&paging_bts->credit_timer, 5, 0); |
| return; |
| } |
| |
| request = llist_entry(paging_bts->pending_requests.next, |
| struct gsm_paging_request, entry); |
| |
| /* we need to determine the number of free channels */ |
| if (paging_bts->free_chans_need != -1) { |
| if (can_send_pag_req(request->bts, request->chan_type) != 0) |
| goto skip_paging; |
| } |
| |
| /* Skip paging if the bts is down. */ |
| if (!request->bts->oml_link) |
| goto skip_paging; |
| |
| /* handle the paging request now */ |
| page_ms(request); |
| paging_bts->available_slots--; |
| request->attempts++; |
| |
| /* take the current and add it to the back */ |
| llist_del(&request->entry); |
| llist_add_tail(&request->entry, &paging_bts->pending_requests); |
| |
| skip_paging: |
| osmo_timer_schedule(&paging_bts->work_timer, PAGING_TIMER); |
| } |
| |
| static void paging_worker(void *data) |
| { |
| struct gsm_bts_paging_state *paging_bts = data; |
| |
| paging_handle_pending_requests(paging_bts); |
| } |
| |
| /*! initialize the bts paging state, if it hasn't been initialized yet */ |
| static void paging_init_if_needed(struct gsm_bts *bts) |
| { |
| if (bts->paging.bts) |
| return; |
| |
| bts->paging.bts = bts; |
| |
| /* This should be initialized only once. There is currently no code that sets bts->paging.bts |
| * back to NULL, so let's just assert this one instead of graceful handling. */ |
| OSMO_ASSERT(llist_empty(&bts->paging.pending_requests)); |
| |
| osmo_timer_setup(&bts->paging.work_timer, paging_worker, |
| &bts->paging); |
| |
| /* Large number, until we get a proper message */ |
| bts->paging.available_slots = 20; |
| } |
| |
| /*! do we have any pending paging requests for given subscriber? */ |
| static int paging_pending_request(struct gsm_bts_paging_state *bts, |
| struct bsc_subscr *bsub) |
| { |
| struct gsm_paging_request *req; |
| |
| llist_for_each_entry(req, &bts->pending_requests, entry) { |
| if (bsub == req->bsub) |
| return 1; |
| } |
| |
| return 0; |
| } |
| |
| /*! Call-back once T3113 (paging timeout) expires for given paging_request */ |
| static void paging_T3113_expired(void *data) |
| { |
| struct gsm_paging_request *req = (struct gsm_paging_request *)data; |
| |
| log_set_context(LOG_CTX_BSC_SUBSCR, req->bsub); |
| |
| LOGP(DPAG, LOGL_INFO, "T3113 expired for request %p (%s)\n", |
| req, bsc_subscr_name(req->bsub)); |
| |
| /* must be destroyed before calling cbfn, to prevent double free */ |
| rate_ctr_inc(&req->bts->bts_ctrs->ctr[BTS_CTR_PAGING_EXPIRED]); |
| |
| /* destroy it now. Do not access req afterwards */ |
| paging_remove_request(&req->bts->paging, req); |
| |
| log_set_context(LOG_CTX_BSC_SUBSCR, NULL); |
| } |
| |
| #define GSM_FRAME_DURATION_us 4615 |
| #define GSM51_MFRAME_DURATION_us (51 * GSM_FRAME_DURATION_us) /* 235365 us */ |
| static unsigned int calculate_timer_3113(struct gsm_bts *bts) |
| { |
| unsigned int to_us, to; |
| struct osmo_tdef *d = osmo_tdef_get_entry(bts->network->T_defs, 3113); |
| |
| /* Note: d should always contain a valid pointer since all timers, |
| * including 3113 are statically pre-defined in |
| * struct osmo_tdef gsm_network_T_defs. */ |
| OSMO_ASSERT(d); |
| |
| if (!bts->T3113_dynamic) |
| return d->val; |
| |
| /* TODO: take into account load of paging group for req->bsub */ |
| |
| /* MFRMS defines repeat interval of paging messages for MSs that belong |
| * to same paging group across multiple 51 frame multiframes. |
| * MAXTRANS defines maximum number of RACH retransmissions. |
| */ |
| to_us = GSM51_MFRAME_DURATION_us * (bts->si_common.chan_desc.bs_pa_mfrms + 2) * |
| bts->si_common.rach_control.max_trans; |
| |
| /* ceiling in seconds + extra time */ |
| to = (to_us + 999999) / 1000000 + d->val; |
| LOG_BTS(bts, DPAG, LOGL_DEBUG, "Paging request: T3113 expires in %u seconds\n", to); |
| return to; |
| } |
| |
| /*! Start paging + paging timer for given subscriber on given BTS |
| * \param bts BTS on which to page |
| * \param[in] bsub subscriber we want to page |
| * \param[in] type type of radio channel we're requirign |
| * \param[in] msc MSC which has issue this paging |
| * \returns 0 on success, negative on error */ |
| static int _paging_request(struct gsm_bts *bts, struct bsc_subscr *bsub, int type, |
| struct bsc_msc_data *msc) |
| { |
| struct gsm_bts_paging_state *bts_entry = &bts->paging; |
| struct gsm_paging_request *req; |
| unsigned int t3113_timeout_s; |
| |
| rate_ctr_inc(&bts->bts_ctrs->ctr[BTS_CTR_PAGING_ATTEMPTED]); |
| |
| if (paging_pending_request(bts_entry, bsub)) { |
| LOG_BTS(bts, DPAG, LOGL_INFO, "Paging request already pending for %s\n", |
| bsc_subscr_name(bsub)); |
| rate_ctr_inc(&bts->bts_ctrs->ctr[BTS_CTR_PAGING_ALREADY]); |
| return -EEXIST; |
| } |
| |
| LOG_BTS(bts, DPAG, LOGL_DEBUG, "Start paging of subscriber %s\n", bsc_subscr_name(bsub)); |
| req = talloc_zero(tall_paging_ctx, struct gsm_paging_request); |
| OSMO_ASSERT(req); |
| req->bsub = bsc_subscr_get(bsub); |
| req->bts = bts; |
| req->chan_type = type; |
| req->msc = msc; |
| osmo_timer_setup(&req->T3113, paging_T3113_expired, req); |
| t3113_timeout_s = calculate_timer_3113(bts); |
| osmo_timer_schedule(&req->T3113, t3113_timeout_s, 0); |
| llist_add_tail(&req->entry, &bts_entry->pending_requests); |
| paging_schedule_if_needed(bts_entry); |
| |
| return 0; |
| } |
| |
| /*! Handle PAGING request from MSC for one (matching) BTS |
| * \param bts BTS on which to page |
| * \param[in] bsub subscriber we want to page |
| * \param[in] type type of radio channel we're requirign |
| * \param[in] msc MSC which has issue this paging |
| * returns 1 on success; 0 in case of error (e.g. TRX down) */ |
| int paging_request_bts(struct gsm_bts *bts, struct bsc_subscr *bsub, int type, |
| struct bsc_msc_data *msc) |
| { |
| int rc; |
| |
| /* skip all currently inactive TRX */ |
| if (!trx_is_usable(bts->c0)) |
| return 0; |
| |
| /* maybe it is the first time we use it */ |
| paging_init_if_needed(bts); |
| |
| /* Trigger paging, pass any error to the caller */ |
| rc = _paging_request(bts, bsub, type, msc); |
| if (rc < 0) |
| return 0; |
| return 1; |
| } |
| |
| /*! Stop paging a given subscriber on a given BTS. |
| * If \a conn is non-NULL, we also call the paging call-back function |
| * to notify the paging originator that paging has completed. |
| * \param[in] bts BTS on which we shall stop paging |
| * \param[in] bsub subscriber which we shall stop paging |
| * \returns the MSC that paged the subscriber, if there was a pending request. |
| */ |
| static struct bsc_msc_data *paging_request_stop_bts(struct gsm_bts *bts, struct bsc_subscr *bsub) |
| { |
| struct gsm_bts_paging_state *bts_entry = &bts->paging; |
| struct gsm_paging_request *req, *req2; |
| |
| paging_init_if_needed(bts); |
| |
| llist_for_each_entry_safe(req, req2, &bts_entry->pending_requests, |
| entry) { |
| if (req->bsub == bsub) { |
| struct bsc_msc_data *from_msc = req->msc; |
| /* now give up the data structure */ |
| paging_remove_request(&bts->paging, req); |
| LOG_BTS(bts, DPAG, LOGL_DEBUG, "Stop paging %s\n", bsc_subscr_name(bsub)); |
| return from_msc; |
| } |
| } |
| |
| return NULL; |
| } |
| |
| /*! Stop paging on all other bts' |
| * \param[in] bts BTS which has received a paging response |
| * \param[in] bsub subscriber |
| * \returns the MSC that paged the subscriber, if there was a pending request. |
| */ |
| struct bsc_msc_data *paging_request_stop(struct gsm_bts *bts, struct bsc_subscr *bsub) |
| { |
| struct gsm_bts *bts_i; |
| struct bsc_msc_data *paged_from_msc; |
| OSMO_ASSERT(bts); |
| |
| paged_from_msc = paging_request_stop_bts(bts, bsub); |
| if (paged_from_msc) { |
| rate_ctr_inc(&bts->bts_ctrs->ctr[BTS_CTR_PAGING_RESPONDED]); |
| rate_ctr_inc(&bts->network->bsc_ctrs->ctr[BSC_CTR_PAGING_RESPONDED]); |
| } |
| |
| llist_for_each_entry(bts_i, &bsc_gsmnet->bts_list, list) { |
| struct bsc_msc_data *paged_from_msc2 = paging_request_stop_bts(bts_i, bsub); |
| if (!paged_from_msc && paged_from_msc2) { |
| /* If this happened, it would be a bit weird: it means there was no Paging Request |
| * pending on the BTS that sent the Paging Reponse, but there *is* a Paging Request |
| * pending on a different BTS. But why not return an MSC when we found one. */ |
| paged_from_msc = paged_from_msc2; |
| } |
| } |
| |
| return paged_from_msc; |
| } |
| |
| /*! Update the BTS paging buffer slots on given BTS */ |
| void paging_update_buffer_space(struct gsm_bts *bts, uint16_t free_slots) |
| { |
| paging_init_if_needed(bts); |
| |
| osmo_timer_del(&bts->paging.credit_timer); |
| bts->paging.available_slots = free_slots; |
| paging_schedule_if_needed(&bts->paging); |
| } |
| |
| /*! Count the number of pending paging requests on given BTS */ |
| unsigned int paging_pending_requests_nr(struct gsm_bts *bts) |
| { |
| unsigned int requests = 0; |
| struct gsm_paging_request *req; |
| |
| paging_init_if_needed(bts); |
| |
| llist_for_each_entry(req, &bts->paging.pending_requests, entry) |
| ++requests; |
| |
| return requests; |
| } |
| |
| /*! Flush all paging requests at a given BTS for a given MSC (or NULL if all MSC should be flushed). */ |
| void paging_flush_bts(struct gsm_bts *bts, struct bsc_msc_data *msc) |
| { |
| struct gsm_paging_request *req, *req2; |
| int num_cancelled = 0; |
| |
| paging_init_if_needed(bts); |
| |
| llist_for_each_entry_safe(req, req2, &bts->paging.pending_requests, entry) { |
| if (msc && req->msc != msc) |
| continue; |
| /* now give up the data structure */ |
| LOG_BTS(bts, DPAG, LOGL_DEBUG, "Stop paging %s (flush)\n", bsc_subscr_name(req->bsub)); |
| paging_remove_request(&bts->paging, req); |
| num_cancelled++; |
| } |
| |
| rate_ctr_add(&bts->bts_ctrs->ctr[BTS_CTR_PAGING_MSC_FLUSH], num_cancelled); |
| } |
| |
| /*! Flush all paging requests issued by \a msc on any BTS in \a net */ |
| void paging_flush_network(struct gsm_network *net, struct bsc_msc_data *msc) |
| { |
| struct gsm_bts *bts; |
| |
| llist_for_each_entry(bts, &net->bts_list, list) |
| paging_flush_bts(bts, msc); |
| } |