diff options
author | Holger Hans Peter Freyther <zecke@selfish.org> | 2009-12-22 07:58:24 +0100 |
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committer | Holger Hans Peter Freyther <zecke@selfish.org> | 2009-12-22 08:02:13 +0100 |
commit | 5c18ad08293ae6f95edd75e6bcc370fd6cff069b (patch) | |
tree | 120273d6da84a0bdb52b32f981714e9bcaea0f59 /openbsc/src/handover_logic.c | |
parent | 0d9ed87d5c7d5b6e21dc3bbb282e215068742566 (diff) | |
parent | 4f5456c040c2dd0c53fe28cb51219d668d464a21 (diff) |
Merge commit 'origin/master' into on-waves/bsc-master
Conflicts:
openbsc/include/openbsc/Makefile.am
openbsc/include/openbsc/gsm_data.h
openbsc/src/Makefile.am
openbsc/src/abis_rsl.c
openbsc/src/chan_alloc.c
openbsc/src/gsm_04_08.c
openbsc/src/gsm_data.c
openbsc/src/vty_interface.c
The biggest problem is the moving of the RTP code into
the RSL layer. This may break quite some things...
Diffstat (limited to 'openbsc/src/handover_logic.c')
-rw-r--r-- | openbsc/src/handover_logic.c | 367 |
1 files changed, 367 insertions, 0 deletions
diff --git a/openbsc/src/handover_logic.c b/openbsc/src/handover_logic.c new file mode 100644 index 000000000..d40374f10 --- /dev/null +++ b/openbsc/src/handover_logic.c @@ -0,0 +1,367 @@ +/* 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 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. + * + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> +#include <time.h> +#include <netinet/in.h> + +#include <openbsc/msgb.h> +#include <openbsc/debug.h> +#include <openbsc/gsm_data.h> +#include <openbsc/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 <openbsc/talloc.h> +#include <openbsc/transaction.h> +#include <openbsc/rtp_proxy.h> + +struct bsc_handover { + struct llist_head list; + + struct gsm_lchan *old_lchan; + struct gsm_lchan *new_lchan; + + struct timer_list T3103; + + u_int8_t ho_ref; +}; + +static LLIST_HEAD(bsc_handovers); + +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; +} + +/* Hand over the specified logical channel to the specified new BTS. + * This is the main entry point for the actual handover algorithm, + * after it has decided it wants 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 u_int8_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); + + bts->network->stats.handover.attempted++; + + new_lchan = lchan_alloc(bts, old_lchan->type); + if (!new_lchan) { + LOGP(DHO, LOGL_NOTICE, "No free channel\n"); + bts->network->stats.handover.no_channel++; + return -ENOSPC; + } + + ho = talloc_zero(NULL, 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; + new_lchan->subscr = subscr_get(old_lchan->subscr); + + /* FIXME: do we have a better idea of the timing advance? */ + rc = rsl_chan_activate_lchan(new_lchan, RSL_ACT_INTER_ASYNC, 0, + ho->ho_ref); + if (rc < 0) { + LOGP(DHO, LOGL_ERROR, "could not activate channel\n"); + talloc_free(ho); + lchan_free(new_lchan); + return rc; + } + + llist_add(&ho->list, &bsc_handovers); + /* we continue in the SS_LCHAN handler / ho_chan_activ_ack */ + + return 0; +} + +/* T3103 expired: Handover has failed without HO COMPLETE or HO FAIL */ +static void ho_T3103_cb(void *_ho) +{ + struct bsc_handover *ho = _ho; + + DEBUGP(DHO, "HO T3103 expired\n"); + ho->new_lchan->ts->trx->bts->network->stats.handover.timeout++; + + lchan_free(ho->new_lchan); + llist_del(&ho->list); + talloc_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; + int rc; + + /* 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 */ + + rc = 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 */ + ho->T3103.cb = ho_T3103_cb; + ho->T3103.data = ho; + bsc_schedule_timer(&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_ERROR, "unable to find HO record\n"); + return -ENODEV; + } + + llist_del(&ho->list); + talloc_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 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; + } + + new_lchan->ts->trx->bts->network->stats.handover.completed++; + + bsc_del_timer(&ho->T3103); + + /* update lchan pointer of transaction */ + trans_lchan_change(ho->old_lchan, new_lchan); + + ho->old_lchan->state = LCHAN_S_INACTIVE; + + /* do something to re-route the actual speech frames ! */ + + llist_del(&ho->list); + talloc_free(ho); + + return 0; +} + +/* GSM 04.08 HANDOVER FAIL has been received */ +static int ho_gsm48_ho_fail(struct gsm_lchan *old_lchan) +{ + struct bsc_handover *ho; + + ho = bsc_ho_by_old_lchan(old_lchan); + if (!ho) { + LOGP(DHO, LOGL_ERROR, "unable to find HO record\n"); + return -ENODEV; + } + + old_lchan->ts->trx->bts->network->stats.handover.failed++; + + bsc_del_timer(&ho->T3103); + llist_del(&ho->list); + put_lchan(ho->new_lchan); + talloc_free(ho); + + 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_ipac_crcx_ack(struct gsm_lchan *new_lchan) +{ + struct bsc_handover *ho; + struct rtp_socket *old_rs, *new_rs, *other_rs; + + ho = bsc_ho_by_new_lchan(new_lchan); + if (!ho) { + LOGP(DHO, LOGL_ERROR, "unable to find HO record\n"); + return -ENODEV; + } + + if (ipacc_rtp_direct) { + LOGP(DHO, LOGL_ERROR, "unable to handover in direct RTP mode\n"); + return 0; + } + + /* RTP Proxy mode */ + new_rs = new_lchan->abis_ip.rtp_socket; + old_rs = ho->old_lchan->abis_ip.rtp_socket; + + if (!new_rs) { + LOGP(DHO, LOGL_ERROR, "no RTP socket for new_lchan\n"); + return -EIO; + } + + rsl_ipacc_mdcx_to_rtpsock(new_lchan); + + if (!old_rs) { + LOGP(DHO, LOGL_ERROR, "no RTP socekt for old_lchan\n"); + return -EIO; + } + + /* copy rx_action and reference to other sock */ + new_rs->rx_action = old_rs->rx_action; + new_rs->tx_action = old_rs->tx_action; + new_rs->transmit = old_rs->transmit; + + switch (ho->old_lchan->abis_ip.rtp_socket->rx_action) { + case RTP_PROXY: + other_rs = old_rs->proxy.other_sock; + rtp_socket_proxy(new_rs, other_rs); + /* delete reference to other end socket to prevent + * rtp_socket_free() from removing the inverse reference */ + old_rs->proxy.other_sock = NULL; + break; + case RTP_RECV_UPSTREAM: + new_rs->receive = old_rs->receive; + break; + case RTP_NONE: + break; + } + + return 0; +} + +static int ho_logic_sig_cb(unsigned int subsys, unsigned int signal, + void *handler_data, void *signal_data) +{ + struct gsm_lchan *lchan; + + switch (subsys) { + case SS_LCHAN: + lchan = signal_data; + 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; + case SS_ABISIP: + lchan = signal_data; + switch (signal) { + case S_ABISIP_CRCX_ACK: + return ho_ipac_crcx_ack(lchan); + break; + } + break; + default: + break; + } + + return 0; +} + +static __attribute__((constructor)) void on_dso_load_ho_logic(void) +{ + register_signal_handler(SS_LCHAN, ho_logic_sig_cb, NULL); + register_signal_handler(SS_ABISIP, ho_logic_sig_cb, NULL); +} |