src/libmsc/osmo_msc.c

/* main MSC management code... */

/*
 * (C) 2010 by Holger Hans Peter Freyther <zecke@selfish.org>
 * (C) 2010 by On-Waves
 *
 * 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 <openbsc/bsc_api.h>
#include <openbsc/debug.h>
#include <openbsc/transaction.h>

#include <openbsc/gsm_04_11.h>

static void msc_sapi_n_reject(struct gsm_subscriber_connection *conn, int dlci)
{
	int sapi = dlci & 0x7;

	if (sapi == UM_SAPI_SMS)
		gsm411_sapi_n_reject(conn);
}

static int msc_clear_request(struct gsm_subscriber_connection *conn, uint32_t cause)
{
	gsm0408_clear_request(conn, cause);
	if (conn->put_channel) {
		conn->put_channel = 0;
		subscr_put_channel(conn->subscr);
	}
	return 1;
}

static int msc_compl_l3(struct gsm_subscriber_connection *conn, struct msgb *msg,
			uint16_t chosen_channel)
{
	gsm0408_new_conn(conn);
	gsm0408_dispatch(conn, msg);

	/* TODO: do better */
	return BSC_API_CONN_POL_ACCEPT;
}

static void msc_dtap(struct gsm_subscriber_connection *conn, uint8_t link_id, struct msgb *msg)
{
	gsm0408_dispatch(conn, msg);
}

static struct bsc_api msc_handler = {
	.sapi_n_reject = msc_sapi_n_reject,
	.clear_request = msc_clear_request,
	.compl_l3 = msc_compl_l3,
	.dtap  = msc_dtap,
};

struct bsc_api *msc_bsc_api() {
	return &msc_handler;
}

/* lchan release handling */
void msc_release_connection(struct gsm_subscriber_connection *conn)
{
	struct gsm_trans *trans;

	/* skip when we are in release, e.g. due an error */
	if (conn->in_release)
		return;

	/* skip releasing of silent calls as they have no transaction */
	if (conn->silent_call)
		return;

	/* check if there is a pending operation */
	if (conn->loc_operation || conn->sec_operation || conn->anch_operation)
		return;

	llist_for_each_entry(trans, &conn->bts->network->trans_list, entry) {
		if (trans->conn == conn)
			return;
	}

	/* no more connections, asking to release the channel */
	conn->in_release = 1;
	gsm0808_clear(conn);
	if (conn->put_channel) {
		conn->put_channel = 0;
		subscr_put_channel(conn->subscr);
	}
	subscr_con_free(conn);
}