diff options
Diffstat (limited to 'src/libbsc/chan_alloc.c')
-rw-r--r-- | src/libbsc/chan_alloc.c | 543 |
1 files changed, 543 insertions, 0 deletions
diff --git a/src/libbsc/chan_alloc.c b/src/libbsc/chan_alloc.c new file mode 100644 index 000000000..33b79a0b2 --- /dev/null +++ b/src/libbsc/chan_alloc.c @@ -0,0 +1,543 @@ +/* GSM Channel allocation routines + * + * (C) 2008 by Harald Welte <laforge@gnumonks.org> + * (C) 2008, 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 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/>. + * + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> + +#include <openbsc/gsm_subscriber.h> +#include <openbsc/chan_alloc.h> +#include <openbsc/abis_nm.h> +#include <openbsc/abis_rsl.h> +#include <openbsc/debug.h> +#include <openbsc/rtp_proxy.h> +#include <openbsc/signal.h> + +#include <osmocom/core/talloc.h> + +static int ts_is_usable(struct gsm_bts_trx_ts *ts) +{ + /* FIXME: How does this behave for BS-11 ? */ + if (is_ipaccess_bts(ts->trx->bts)) { + if (!nm_is_running(&ts->mo.nm_state)) + return 0; + } + + /* If a TCH/F_PDCH TS is busy changing, it is already taken or not + * yet available. */ + if (ts->pchan == GSM_PCHAN_TCH_F_PDCH) { + if (ts->flags & TS_F_PDCH_PENDING_MASK) + return 0; + } + + /* If a dynamic channel is busy changing, it is already taken or not + * yet available. */ + if (ts->pchan == GSM_PCHAN_TCH_F_TCH_H_PDCH) { + if (ts->dyn.pchan_is != ts->dyn.pchan_want) + return 0; + } + + return 1; +} + +int trx_is_usable(struct gsm_bts_trx *trx) +{ + /* FIXME: How does this behave for BS-11 ? */ + if (is_ipaccess_bts(trx->bts)) { + if (!nm_is_running(&trx->mo.nm_state) || + !nm_is_running(&trx->bb_transc.mo.nm_state)) + return 0; + } + + return 1; +} + +static struct gsm_lchan * +_lc_find_trx(struct gsm_bts_trx *trx, enum gsm_phys_chan_config pchan, + enum gsm_phys_chan_config dyn_as_pchan) +{ + struct gsm_bts_trx_ts *ts; + int j, start, stop, dir, ss; + int check_subslots; + + if (!trx_is_usable(trx)) + return NULL; + + if (trx->bts->chan_alloc_reverse) { + /* check TS 7..0 */ + start = 7; + stop = -1; + dir = -1; + } else { + /* check TS 0..7 */ + start = 0; + stop = 8; + dir = 1; + } + + for (j = start; j != stop; j += dir) { + ts = &trx->ts[j]; + if (!ts_is_usable(ts)) + continue; + if (ts->pchan != pchan) + continue; + + /* + * Allocation for fully dynamic timeslots + * (does not apply for ip.access style GSM_PCHAN_TCH_F_PDCH) + * + * Note the special nature of a dynamic timeslot in PDCH mode: + * in PDCH mode, typically, lchan->type is GSM_LCHAN_NONE and + * lchan->state is LCHAN_S_NONE -- an otherwise unused slot + * becomes PDCH implicitly. In the same sense, this channel + * allocator will never be asked to find an available PDCH + * slot; only TCH/F or TCH/H will be requested, and PDCH mode + * means that it is available for switchover. + * + * A dynamic timeslot in PDCH mode may be switched to TCH/F or + * TCH/H. If a dyn TS is already in TCH/F or TCH/H mode, it + * means that it is in use and its mode can't be switched. + * + * The logic concerning channels for TCH/F is trivial: there is + * only one channel, so a dynamic TS in TCH/F mode is already + * taken and not available for allocation. For TCH/H, we need + * to check whether a dynamic timeslot is already in TCH/H mode + * and whether one of the two channels is still available. + */ + switch (pchan) { + case GSM_PCHAN_TCH_F_TCH_H_PDCH: + if (ts->dyn.pchan_is != ts->dyn.pchan_want) { + /* The TS's mode is being switched. Not + * available anymore/yet. */ + DEBUGP(DRLL, "%s already in switchover\n", + gsm_ts_and_pchan_name(ts)); + continue; + } + if (ts->dyn.pchan_is == GSM_PCHAN_PDCH) { + /* This slot is available. Still check for + * error states to be sure; in all cases the + * first lchan will be used. */ + if (ts->lchan->state != LCHAN_S_NONE + && ts->lchan->state != LCHAN_S_ACTIVE) + continue; + return ts->lchan; + } + if (ts->dyn.pchan_is != dyn_as_pchan) + /* not applicable. */ + continue; + /* The requested type matches the dynamic timeslot's + * current mode. A channel may still be available + * (think TCH/H). */ + check_subslots = ts_subslots(ts); + break; + + case GSM_PCHAN_TCH_F_PDCH: + /* Available for voice when in PDCH mode */ + if (ts_pchan(ts) != GSM_PCHAN_PDCH) + continue; + /* Subslots of a PDCH ts don't need to be checked. */ + return ts->lchan; + + default: + /* Not a dynamic channel, there is only one pchan kind: */ + check_subslots = ts_subslots(ts); + break; + } + + /* Is a sub-slot still available? */ + for (ss = 0; ss < check_subslots; ss++) { + struct gsm_lchan *lc = &ts->lchan[ss]; + if (lc->type == GSM_LCHAN_NONE && + lc->state == LCHAN_S_NONE) + return lc; + } + } + + return NULL; +} + +static struct gsm_lchan * +_lc_dyn_find_bts(struct gsm_bts *bts, enum gsm_phys_chan_config pchan, + enum gsm_phys_chan_config dyn_as_pchan) +{ + struct gsm_bts_trx *trx; + struct gsm_lchan *lc; + + if (bts->chan_alloc_reverse) { + llist_for_each_entry_reverse(trx, &bts->trx_list, list) { + lc = _lc_find_trx(trx, pchan, dyn_as_pchan); + if (lc) + return lc; + } + } else { + llist_for_each_entry(trx, &bts->trx_list, list) { + lc = _lc_find_trx(trx, pchan, dyn_as_pchan); + if (lc) + return lc; + } + } + + return NULL; +} + +static struct gsm_lchan * +_lc_find_bts(struct gsm_bts *bts, enum gsm_phys_chan_config pchan) +{ + return _lc_dyn_find_bts(bts, pchan, GSM_PCHAN_NONE); +} + +/* Allocate a logical channel. + * + * Dynamic channel types: we always prefer a dedicated TS, and only pick + + * switch a dynamic TS if no pure TS of the requested PCHAN is available. + * + * TCH_F/PDCH: if we pick a PDCH ACT style dynamic TS as TCH/F channel, PDCH + * will be disabled in rsl_chan_activate_lchan(); there is no need to check + * whether PDCH mode is currently active, here. + */ +struct gsm_lchan *lchan_alloc(struct gsm_bts *bts, enum gsm_chan_t type, + int allow_bigger) +{ + struct gsm_lchan *lchan = NULL; + enum gsm_phys_chan_config first, first_cbch, second, second_cbch; + + switch (type) { + case GSM_LCHAN_SDCCH: + if (bts->chan_alloc_reverse) { + first = GSM_PCHAN_SDCCH8_SACCH8C; + first_cbch = GSM_PCHAN_SDCCH8_SACCH8C_CBCH; + second = GSM_PCHAN_CCCH_SDCCH4; + second_cbch = GSM_PCHAN_CCCH_SDCCH4_CBCH; + } else { + first = GSM_PCHAN_CCCH_SDCCH4; + first_cbch = GSM_PCHAN_CCCH_SDCCH4_CBCH; + second = GSM_PCHAN_SDCCH8_SACCH8C; + second_cbch = GSM_PCHAN_SDCCH8_SACCH8C_CBCH; + } + + lchan = _lc_find_bts(bts, first); + if (lchan == NULL) + lchan = _lc_find_bts(bts, first_cbch); + if (lchan == NULL) + lchan = _lc_find_bts(bts, second); + if (lchan == NULL) + lchan = _lc_find_bts(bts, second_cbch); + + /* allow to assign bigger channels */ + if (allow_bigger) { + if (lchan == NULL) { + lchan = _lc_find_bts(bts, GSM_PCHAN_TCH_H); + if (lchan) + type = GSM_LCHAN_TCH_H; + } + + if (lchan == NULL) { + lchan = _lc_find_bts(bts, GSM_PCHAN_TCH_F); + if (lchan) + type = GSM_LCHAN_TCH_F; + } + + /* try dynamic TCH/F_PDCH */ + if (lchan == NULL) { + lchan = _lc_find_bts(bts, GSM_PCHAN_TCH_F_PDCH); + /* TCH/F_PDCH will be used as TCH/F */ + if (lchan) + type = GSM_LCHAN_TCH_F; + } + + /* try fully dynamic TCH/F_TCH/H_PDCH */ + if (lchan == NULL) { + lchan = _lc_dyn_find_bts(bts, GSM_PCHAN_TCH_F_TCH_H_PDCH, + GSM_PCHAN_TCH_H); + if (lchan) + type = GSM_LCHAN_TCH_H; + } + /* + * No need to check fully dynamic channels for TCH/F: + * if no TCH/H was available, neither will be TCH/F. + */ + } + break; + case GSM_LCHAN_TCH_F: + lchan = _lc_find_bts(bts, GSM_PCHAN_TCH_F); + /* If we don't have TCH/F available, fall-back to TCH/H */ + if (!lchan) { + lchan = _lc_find_bts(bts, GSM_PCHAN_TCH_H); + if (lchan) + type = GSM_LCHAN_TCH_H; + } + /* If we don't have TCH/H either, try dynamic TCH/F_PDCH */ + if (!lchan) { + lchan = _lc_find_bts(bts, GSM_PCHAN_TCH_F_PDCH); + /* TCH/F_PDCH used as TCH/F -- here, type is already + * set to GSM_LCHAN_TCH_F, but for clarity's sake... */ + if (lchan) + type = GSM_LCHAN_TCH_F; + } + + /* Try fully dynamic TCH/F_TCH/H_PDCH as TCH/F... */ + if (!lchan && bts->network->dyn_ts_allow_tch_f) { + lchan = _lc_dyn_find_bts(bts, + GSM_PCHAN_TCH_F_TCH_H_PDCH, + GSM_PCHAN_TCH_F); + if (lchan) + type = GSM_LCHAN_TCH_F; + } + /* ...and as TCH/H. */ + if (!lchan) { + lchan = _lc_dyn_find_bts(bts, + GSM_PCHAN_TCH_F_TCH_H_PDCH, + GSM_PCHAN_TCH_H); + if (lchan) + type = GSM_LCHAN_TCH_H; + } + break; + case GSM_LCHAN_TCH_H: + lchan = _lc_find_bts(bts, GSM_PCHAN_TCH_H); + /* If we don't have TCH/H available, fall-back to TCH/F */ + if (!lchan) { + lchan = _lc_find_bts(bts, GSM_PCHAN_TCH_F); + if (lchan) + type = GSM_LCHAN_TCH_F; + } + /* No dedicated TCH/x available -- try fully dynamic + * TCH/F_TCH/H_PDCH */ + if (!lchan) { + lchan = _lc_dyn_find_bts(bts, + GSM_PCHAN_TCH_F_TCH_H_PDCH, + GSM_PCHAN_TCH_H); + if (lchan) + type = GSM_LCHAN_TCH_H; + } + /* + * No need to check TCH/F_TCH/H_PDCH channels for TCH/F: + * if no TCH/H was available, neither will be TCH/F. + */ + /* If we don't have TCH/F either, try dynamic TCH/F_PDCH */ + if (!lchan) { + lchan = _lc_find_bts(bts, GSM_PCHAN_TCH_F_PDCH); + if (lchan) + type = GSM_LCHAN_TCH_F; + } + break; + default: + LOGP(DRLL, LOGL_ERROR, "Unknown gsm_chan_t %u\n", type); + } + + if (lchan) { + lchan->type = type; + + LOGP(DRLL, LOGL_INFO, "%s Allocating lchan=%u as %s\n", + gsm_ts_and_pchan_name(lchan->ts), + lchan->nr, gsm_lchant_name(lchan->type)); + + /* clear sapis */ + memset(lchan->sapis, 0, ARRAY_SIZE(lchan->sapis)); + + /* clear multi rate config */ + memset(&lchan->mr_ms_lv, 0, sizeof(lchan->mr_ms_lv)); + memset(&lchan->mr_bts_lv, 0, sizeof(lchan->mr_bts_lv)); + lchan->broken_reason = ""; + } else { + struct challoc_signal_data sig; + + LOGP(DRLL, LOGL_ERROR, "Failed to allocate %s channel\n", + gsm_lchant_name(type)); + + sig.bts = bts; + sig.type = type; + osmo_signal_dispatch(SS_CHALLOC, S_CHALLOC_ALLOC_FAIL, &sig); + } + + return lchan; +} + +/* Free a logical channel */ +void lchan_free(struct gsm_lchan *lchan) +{ + struct challoc_signal_data sig; + int i; + + sig.type = lchan->type; + lchan->type = GSM_LCHAN_NONE; + + + if (lchan->conn) { + struct lchan_signal_data sig; + + /* We might kill an active channel... */ + sig.lchan = lchan; + sig.mr = NULL; + osmo_signal_dispatch(SS_LCHAN, S_LCHAN_UNEXPECTED_RELEASE, &sig); + } + + if (lchan->abis_ip.rtp_socket) { + LOGP(DRLL, LOGL_ERROR, "%s RTP Proxy Socket remained open.\n", + gsm_lchan_name(lchan)); + rtp_socket_free(lchan->abis_ip.rtp_socket); + lchan->abis_ip.rtp_socket = NULL; + } + + /* stop the timer */ + osmo_timer_del(&lchan->T3101); + + /* clear cached measuement reports */ + lchan->meas_rep_idx = 0; + for (i = 0; i < ARRAY_SIZE(lchan->meas_rep); i++) { + lchan->meas_rep[i].flags = 0; + lchan->meas_rep[i].nr = 0; + } + for (i = 0; i < ARRAY_SIZE(lchan->neigh_meas); i++) + lchan->neigh_meas[i].arfcn = 0; + + if (lchan->rqd_ref) { + talloc_free(lchan->rqd_ref); + lchan->rqd_ref = NULL; + lchan->rqd_ta = 0; + } + + sig.lchan = lchan; + sig.bts = lchan->ts->trx->bts; + osmo_signal_dispatch(SS_CHALLOC, S_CHALLOC_FREED, &sig); + + if (lchan->conn) { + LOGP(DRLL, LOGL_ERROR, "the subscriber connection should be gone.\n"); + lchan->conn = NULL; + } + + /* FIXME: ts_free() the timeslot, if we're the last logical + * channel using it */ +} + +/* + * There was an error with the TRX and we need to forget + * any state so that a lchan can be allocated again after + * the trx is fully usable. + * + * This should be called after lchan_free to force a channel + * be available for allocation again. This means that this + * method will stop the "delay after error"-timer and set the + * state to LCHAN_S_NONE. + */ +void lchan_reset(struct gsm_lchan *lchan) +{ + osmo_timer_del(&lchan->T3101); + osmo_timer_del(&lchan->T3109); + osmo_timer_del(&lchan->T3111); + osmo_timer_del(&lchan->error_timer); + + lchan->type = GSM_LCHAN_NONE; + lchan->state = LCHAN_S_NONE; + + if (lchan->abis_ip.rtp_socket) { + rtp_socket_free(lchan->abis_ip.rtp_socket); + lchan->abis_ip.rtp_socket = NULL; + } +} + +/* Drive the release process of the lchan */ +static void _lchan_handle_release(struct gsm_lchan *lchan, + int sacch_deact, int mode) +{ + /* Release all SAPIs on the local end and continue */ + rsl_release_sapis_from(lchan, 1, RSL_REL_LOCAL_END); + + /* + * Shall we send a RR Release, start T3109 and wait for the + * release indication from the BTS or just take it down (e.g. + * on assignment requests) + */ + if (sacch_deact) { + gsm48_send_rr_release(lchan); + + /* Deactivate the SACCH on the BTS side */ + rsl_deact_sacch(lchan); + rsl_start_t3109(lchan); + } else if (lchan->sapis[0] == LCHAN_SAPI_UNUSED) { + rsl_direct_rf_release(lchan); + } else { + rsl_release_request(lchan, 0, mode); + } +} + +/* Consider releasing the channel now */ +int lchan_release(struct gsm_lchan *lchan, int sacch_deact, enum rsl_rel_mode mode) +{ + DEBUGP(DRLL, "%s starting release sequence\n", gsm_lchan_name(lchan)); + rsl_lchan_set_state(lchan, LCHAN_S_REL_REQ); + + lchan->conn = NULL; + _lchan_handle_release(lchan, sacch_deact, mode); + return 1; +} + +void bts_chan_load(struct pchan_load *cl, const struct gsm_bts *bts) +{ + struct gsm_bts_trx *trx; + + llist_for_each_entry(trx, &bts->trx_list, list) { + int i; + + /* skip administratively deactivated tranxsceivers */ + if (!nm_is_running(&trx->mo.nm_state) || + !nm_is_running(&trx->bb_transc.mo.nm_state)) + continue; + + for (i = 0; i < ARRAY_SIZE(trx->ts); i++) { + struct gsm_bts_trx_ts *ts = &trx->ts[i]; + struct load_counter *pl = &cl->pchan[ts->pchan]; + int j; + int subslots; + + /* skip administratively deactivated timeslots */ + if (!nm_is_running(&ts->mo.nm_state)) + continue; + + subslots = ts_subslots(ts); + for (j = 0; j < subslots; j++) { + struct gsm_lchan *lchan = &ts->lchan[j]; + + pl->total++; + + switch (lchan->state) { + case LCHAN_S_NONE: + break; + default: + pl->used++; + break; + } + } + } + } +} + +void network_chan_load(struct pchan_load *pl, struct gsm_network *net) +{ + struct gsm_bts *bts; + + memset(pl, 0, sizeof(*pl)); + + llist_for_each_entry(bts, &net->bts_list, list) + bts_chan_load(pl, bts); +} + |