/* main MSC management code... */

/*
 * (C) 2010,2013 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/osmo_msc.h>
#include <openbsc/bsc_api.h>
#include <openbsc/debug.h>
#include <openbsc/transaction.h>
#include <openbsc/db.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);
	return 1;
}

/* receive a Level 3 Complete message and return MSC_CONN_ACCEPT or
 * MSC_CONN_REJECT */
int msc_compl_l3(struct gsm_subscriber_connection *conn, struct msgb *msg,
		 uint16_t chosen_channel)
{
	gsm0408_new_conn(conn);
	gsm0408_dispatch(conn, msg);

	/*
	 * If this is a silent call we want the channel to remain open as long as
	 * possible and this is why we accept this connection regardless of any
	 * pending transaction or ongoing operation.
	 */
	if (conn->silent_call)
		return MSC_CONN_ACCEPT;
	if (conn->loc_operation || conn->sec_operation || conn->anch_operation)
		return MSC_CONN_ACCEPT;
	if (trans_has_conn(conn))
		return MSC_CONN_ACCEPT;

	LOGP(DRR, LOGL_INFO, "MSC Complete L3: Rejecting connection.\n");
	return MSC_CONN_REJECT;
}

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

static void msc_assign_compl(struct gsm_subscriber_connection *conn,
			     uint8_t rr_cause, uint8_t chosen_channel,
			     uint8_t encr_alg_id, uint8_t speec)
{
	LOGP(DRR, LOGL_DEBUG, "MSC assign complete (do nothing).\n");
}

static void msc_assign_fail(struct gsm_subscriber_connection *conn,
			    uint8_t cause, uint8_t *rr_cause)
{
	LOGP(DRR, LOGL_DEBUG, "MSC assign failure (do nothing).\n");
}

static void msc_classmark_chg(struct gsm_subscriber_connection *conn,
			      const uint8_t *cm2, uint8_t cm2_len,
			      const uint8_t *cm3, uint8_t cm3_len)
{
	struct gsm_subscriber *subscr = conn->subscr;

	if (subscr) {
		subscr->equipment.classmark2_len = cm2_len;
		memcpy(subscr->equipment.classmark2, cm2, cm2_len);
		if (cm3) {
			subscr->equipment.classmark3_len = cm3_len;
			memcpy(subscr->equipment.classmark3, cm3, cm3_len);
		}
		db_sync_equipment(&subscr->equipment);
	}
}

static void msc_ciph_m_compl(struct gsm_subscriber_connection *conn,
			     struct msgb *msg, uint8_t alg_id)
{
	gsm_cbfn *cb;

	DEBUGP(DRR, "CIPHERING MODE COMPLETE\n");

	/* Safety check */
	if (!conn->sec_operation) {
		DEBUGP(DRR, "No authentication/cipher operation in progress !!!\n");
		return;
	}

	/* FIXME: check for MI (if any) */

	/* Call back whatever was in progress (if anything) ... */
	cb = conn->sec_operation->cb;
	if (cb) {
		cb(GSM_HOOK_RR_SECURITY, GSM_SECURITY_SUCCEEDED,
			NULL, conn, conn->sec_operation->cb_data);

	}

	/* Complete the operation */
	release_security_operation(conn);
}



static struct bsc_api msc_handler = {
	.sapi_n_reject = msc_sapi_n_reject,
	.compl_l3 = msc_compl_l3,
	.dtap = msc_dtap,
	.clear_request = msc_clear_request,
	.assign_compl = msc_assign_compl,
	.assign_fail = msc_assign_fail,
	.classmark_chg = msc_classmark_chg,
	.cipher_mode_compl = msc_ciph_m_compl,
};

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

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

	if (trans_has_conn(conn))
		return;

	/* no more connections, asking to release the channel */

	/*
	 * We had stopped the LU expire timer T3212. Now we are about
	 * to send the MS back to the idle state and this should lead
	 * to restarting the timer. Set the new expiration time.
	 */
	if (conn->expire_timer_stopped)
		subscr_update_expire_lu(conn->subscr);

	conn->in_release = 1;
	msc_subscr_con_free(conn);
}
