diff options
Diffstat (limited to 'openbsc/src/libbsc/handover_logic.c')
| -rw-r--r-- | openbsc/src/libbsc/handover_logic.c | 378 |
1 files changed, 0 insertions, 378 deletions
diff --git a/openbsc/src/libbsc/handover_logic.c b/openbsc/src/libbsc/handover_logic.c deleted file mode 100644 index 4dd913b15..000000000 --- a/openbsc/src/libbsc/handover_logic.c +++ /dev/null @@ -1,378 +0,0 @@ -/* Handover Logic for Inter-BTS (Intra-BSC) Handover. This does not - * actually implement the handover algorithm/decision, but executes a - * handover decision */ - -/* (C) 2009 by Harald Welte <laforge@gnumonks.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 <time.h> -#include <netinet/in.h> - -#include <osmocom/core/msgb.h> -#include <openbsc/debug.h> -#include <openbsc/gsm_data.h> -#include <osmocom/gsm/gsm_utils.h> -#include <openbsc/gsm_subscriber.h> -#include <openbsc/gsm_04_08.h> -#include <openbsc/abis_rsl.h> -#include <openbsc/chan_alloc.h> -#include <openbsc/signal.h> -#include <osmocom/core/talloc.h> -#include <openbsc/transaction.h> -#include <openbsc/trau_mux.h> - -struct bsc_handover { - struct llist_head list; - - struct gsm_lchan *old_lchan; - struct gsm_lchan *new_lchan; - - struct osmo_timer_list T3103; - - uint8_t ho_ref; -}; - -static LLIST_HEAD(bsc_handovers); - -static void handover_free(struct bsc_handover *ho) -{ - osmo_timer_del(&ho->T3103); - llist_del(&ho->list); - talloc_free(ho); -} - -static struct bsc_handover *bsc_ho_by_new_lchan(struct gsm_lchan *new_lchan) -{ - struct bsc_handover *ho; - - llist_for_each_entry(ho, &bsc_handovers, list) { - if (ho->new_lchan == new_lchan) - return ho; - } - - return NULL; -} - -static struct bsc_handover *bsc_ho_by_old_lchan(struct gsm_lchan *old_lchan) -{ - struct bsc_handover *ho; - - llist_for_each_entry(ho, &bsc_handovers, list) { - if (ho->old_lchan == old_lchan) - return ho; - } - - return NULL; -} - -/*! \brief Hand over the specified logical channel to the specified new BTS. - * This is the main entry point for the actual handover algorithm, after the - * decision whether to initiate HO to a specific BTS. */ -int bsc_handover_start(struct gsm_lchan *old_lchan, struct gsm_bts *bts) -{ - struct gsm_lchan *new_lchan; - struct bsc_handover *ho; - static uint8_t ho_ref; - int rc; - - /* don't attempt multiple handovers for the same lchan at - * the same time */ - if (bsc_ho_by_old_lchan(old_lchan)) - return -EBUSY; - - DEBUGP(DHO, "(old_lchan on BTS %u, new BTS %u)\n", - old_lchan->ts->trx->bts->nr, bts->nr); - - rate_ctr_inc(&bts->network->bsc_ctrs->ctr[BSC_CTR_HANDOVER_ATTEMPTED]); - - if (!old_lchan->conn) { - LOGP(DHO, LOGL_ERROR, "Old lchan lacks connection data.\n"); - return -ENOSPC; - } - - new_lchan = lchan_alloc(bts, old_lchan->type, 0); - if (!new_lchan) { - LOGP(DHO, LOGL_NOTICE, "No free channel\n"); - rate_ctr_inc(&bts->network->bsc_ctrs->ctr[BSC_CTR_HANDOVER_NO_CHANNEL]); - return -ENOSPC; - } - - ho = talloc_zero(tall_bsc_ctx, struct bsc_handover); - if (!ho) { - LOGP(DHO, LOGL_FATAL, "Out of Memory\n"); - lchan_free(new_lchan); - return -ENOMEM; - } - ho->old_lchan = old_lchan; - ho->new_lchan = new_lchan; - ho->ho_ref = ho_ref++; - - /* copy some parameters from old lchan */ - memcpy(&new_lchan->encr, &old_lchan->encr, sizeof(new_lchan->encr)); - new_lchan->ms_power = old_lchan->ms_power; - new_lchan->bs_power = old_lchan->bs_power; - new_lchan->rsl_cmode = old_lchan->rsl_cmode; - new_lchan->tch_mode = old_lchan->tch_mode; - memcpy(&new_lchan->mr_ms_lv, &old_lchan->mr_ms_lv, ARRAY_SIZE(new_lchan->mr_ms_lv)); - memcpy(&new_lchan->mr_bts_lv, &old_lchan->mr_bts_lv, ARRAY_SIZE(new_lchan->mr_bts_lv)); - - new_lchan->conn = old_lchan->conn; - new_lchan->conn->ho_lchan = new_lchan; - - /* FIXME: do we have a better idea of the timing advance? */ - rc = rsl_chan_activate_lchan(new_lchan, RSL_ACT_INTER_ASYNC, ho->ho_ref); - if (rc < 0) { - LOGP(DHO, LOGL_ERROR, "could not activate channel\n"); - new_lchan->conn->ho_lchan = NULL; - new_lchan->conn = NULL; - talloc_free(ho); - lchan_free(new_lchan); - return rc; - } - - rsl_lchan_set_state(new_lchan, LCHAN_S_ACT_REQ); - llist_add(&ho->list, &bsc_handovers); - /* we continue in the SS_LCHAN handler / ho_chan_activ_ack */ - - return 0; -} - -void bsc_clear_handover(struct gsm_subscriber_connection *conn, int free_lchan) -{ - struct bsc_handover *ho; - - ho = bsc_ho_by_new_lchan(conn->ho_lchan); - - - if (!ho && conn->ho_lchan) - LOGP(DHO, LOGL_ERROR, "BUG: We lost some state.\n"); - - if (!ho) { - LOGP(DHO, LOGL_ERROR, "unable to find HO record\n"); - return; - } - - conn->ho_lchan->conn = NULL; - conn->ho_lchan = NULL; - - if (free_lchan) - lchan_release(ho->new_lchan, 0, RSL_REL_LOCAL_END); - - handover_free(ho); -} - -/* T3103 expired: Handover has failed without HO COMPLETE or HO FAIL */ -static void ho_T3103_cb(void *_ho) -{ - struct bsc_handover *ho = _ho; - struct gsm_network *net = ho->new_lchan->ts->trx->bts->network; - - DEBUGP(DHO, "HO T3103 expired\n"); - rate_ctr_inc(&net->bsc_ctrs->ctr[BSC_CTR_HANDOVER_TIMEOUT]); - - ho->new_lchan->conn->ho_lchan = NULL; - ho->new_lchan->conn = NULL; - lchan_release(ho->new_lchan, 0, RSL_REL_LOCAL_END); - handover_free(ho); -} - -/* RSL has acknowledged activation of the new lchan */ -static int ho_chan_activ_ack(struct gsm_lchan *new_lchan) -{ - struct bsc_handover *ho; - - /* we need to check if this channel activation is related to - * a handover at all (and if, which particular handover) */ - ho = bsc_ho_by_new_lchan(new_lchan); - if (!ho) - return -ENODEV; - - DEBUGP(DHO, "handover activate ack, send HO Command\n"); - - /* we can now send the 04.08 HANDOVER COMMAND to the MS - * using the old lchan */ - - gsm48_send_ho_cmd(ho->old_lchan, new_lchan, 0, ho->ho_ref); - - /* start T3103. We can continue either with T3103 expiration, - * 04.08 HANDOVER COMPLETE or 04.08 HANDOVER FAIL */ - osmo_timer_setup(&ho->T3103, ho_T3103_cb, ho); - osmo_timer_schedule(&ho->T3103, 10, 0); - - /* create a RTP connection */ - if (is_ipaccess_bts(new_lchan->ts->trx->bts)) - rsl_ipacc_crcx(new_lchan); - - return 0; -} - -/* RSL has not acknowledged activation of the new lchan */ -static int ho_chan_activ_nack(struct gsm_lchan *new_lchan) -{ - struct bsc_handover *ho; - - ho = bsc_ho_by_new_lchan(new_lchan); - if (!ho) { - LOGP(DHO, LOGL_INFO, "ACT NACK: unable to find HO record\n"); - return -ENODEV; - } - - new_lchan->conn->ho_lchan = NULL; - new_lchan->conn = NULL; - handover_free(ho); - - /* FIXME: maybe we should try to allocate a new LCHAN here? */ - - return 0; -} - -/* GSM 04.08 HANDOVER COMPLETE has been received on new channel */ -static int ho_gsm48_ho_compl(struct gsm_lchan *new_lchan) -{ - struct gsm_network *net; - struct bsc_handover *ho; - - ho = bsc_ho_by_new_lchan(new_lchan); - if (!ho) { - LOGP(DHO, LOGL_ERROR, "unable to find HO record\n"); - return -ENODEV; - } - - net = new_lchan->ts->trx->bts->network; - LOGP(DHO, LOGL_INFO, "Subscriber %s HO from BTS %u->%u on ARFCN " - "%u->%u\n", subscr_name(ho->old_lchan->conn->subscr), - ho->old_lchan->ts->trx->bts->nr, new_lchan->ts->trx->bts->nr, - ho->old_lchan->ts->trx->arfcn, new_lchan->ts->trx->arfcn); - - rate_ctr_inc(&net->bsc_ctrs->ctr[BSC_CTR_HANDOVER_COMPLETED]); - - osmo_timer_del(&ho->T3103); - - /* switch TRAU muxer for E1 based BTS from one channel to another */ - if (is_e1_bts(new_lchan->conn->bts)) - switch_trau_mux(ho->old_lchan, new_lchan); - - /* Replace the ho lchan with the primary one */ - if (ho->old_lchan != new_lchan->conn->lchan) - LOGP(DHO, LOGL_ERROR, "Primary lchan changed during handover.\n"); - - if (new_lchan != new_lchan->conn->ho_lchan) - LOGP(DHO, LOGL_ERROR, "Handover channel changed during this handover.\n"); - - new_lchan->conn->ho_lchan = NULL; - new_lchan->conn->lchan = new_lchan; - ho->old_lchan->conn = NULL; - - lchan_release(ho->old_lchan, 0, RSL_REL_LOCAL_END); - - handover_free(ho); - return 0; -} - -/* GSM 04.08 HANDOVER FAIL has been received */ -static int ho_gsm48_ho_fail(struct gsm_lchan *old_lchan) -{ - struct gsm_network *net = old_lchan->ts->trx->bts->network; - struct bsc_handover *ho; - struct gsm_lchan *new_lchan; - - ho = bsc_ho_by_old_lchan(old_lchan); - if (!ho) { - LOGP(DHO, LOGL_ERROR, "unable to find HO record\n"); - return -ENODEV; - } - - rate_ctr_inc(&net->bsc_ctrs->ctr[BSC_CTR_HANDOVER_FAILED]); - - new_lchan = ho->new_lchan; - - /* release the channel and forget about it */ - ho->new_lchan->conn->ho_lchan = NULL; - ho->new_lchan->conn = NULL; - handover_free(ho); - - lchan_release(new_lchan, 0, RSL_REL_LOCAL_END); - - - return 0; -} - -/* GSM 08.58 HANDOVER DETECT has been received */ -static int ho_rsl_detect(struct gsm_lchan *new_lchan) -{ - struct bsc_handover *ho; - - ho = bsc_ho_by_new_lchan(new_lchan); - if (!ho) { - LOGP(DHO, LOGL_ERROR, "unable to find HO record\n"); - return -ENODEV; - } - - /* FIXME: do we actually want to do something here ? */ - - return 0; -} - -static int ho_logic_sig_cb(unsigned int subsys, unsigned int signal, - void *handler_data, void *signal_data) -{ - struct lchan_signal_data *lchan_data; - struct gsm_lchan *lchan; - - lchan_data = signal_data; - switch (subsys) { - case SS_LCHAN: - lchan = lchan_data->lchan; - switch (signal) { - case S_LCHAN_ACTIVATE_ACK: - return ho_chan_activ_ack(lchan); - case S_LCHAN_ACTIVATE_NACK: - return ho_chan_activ_nack(lchan); - case S_LCHAN_HANDOVER_DETECT: - return ho_rsl_detect(lchan); - case S_LCHAN_HANDOVER_COMPL: - return ho_gsm48_ho_compl(lchan); - case S_LCHAN_HANDOVER_FAIL: - return ho_gsm48_ho_fail(lchan); - } - break; - default: - break; - } - - return 0; -} - -struct gsm_lchan *bsc_handover_pending(struct gsm_lchan *new_lchan) -{ - struct bsc_handover *ho; - ho = bsc_ho_by_new_lchan(new_lchan); - if (!ho) - return NULL; - return ho->old_lchan; -} - -static __attribute__((constructor)) void on_dso_load_ho_logic(void) -{ - osmo_signal_register_handler(SS_LCHAN, ho_logic_sig_cb, NULL); -} |