1 files changed, 550 insertions, 0 deletions
diff --git a/src/osmo-bsc/osmo_bsc_api.c b/src/osmo-bsc/osmo_bsc_api.c
new file mode 100644
index 000000000..bac5e4717
--- /dev/null
+++ b/src/osmo-bsc/osmo_bsc_api.c
@@ -0,0 +1,550 @@
+/* (C) 2009-2015 by Holger Hans Peter Freyther <zecke@selfish.org>
+ * (C) 2009-2011 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_bsc.h>
+#include <openbsc/bsc_msc_data.h>
+#include <openbsc/debug.h>
+
+#include <openbsc/gsm_04_80.h>
+
+#include <osmocom/gsm/protocol/gsm_08_08.h>
+#include <osmocom/gsm/gsm0808.h>
+
+#include <osmocom/sccp/sccp.h>
+
+#define return_when_not_connected(conn) \
+	if (!conn->sccp_con) {\
+		LOGP(DMSC, LOGL_ERROR, "MSC Connection not present.\n"); \
+		return; \
+	}
+
+#define return_when_not_connected_val(conn, ret) \
+	if (!conn->sccp_con) {\
+		LOGP(DMSC, LOGL_ERROR, "MSC Connection not present.\n"); \
+		return ret; \
+	}
+
+#define queue_msg_or_return(resp) \
+	if (!resp) { \
+		LOGP(DMSC, LOGL_ERROR, "Failed to allocate response.\n"); \
+		return; \
+	} \
+	bsc_queue_for_msc(conn->sccp_con, resp);
+
+static int bsc_clear_request(struct gsm_subscriber_connection *conn, uint32_t cause);
+static int complete_layer3(struct gsm_subscriber_connection *conn,
+			   struct msgb *msg, struct bsc_msc_data *msc);
+
+static uint16_t get_network_code_for_msc(struct bsc_msc_data *msc)
+{
+	if (msc->core_mnc != -1)
+		return msc->core_mnc;
+	return msc->network->network_code;
+}
+
+static uint16_t get_country_code_for_msc(struct bsc_msc_data *msc)
+{
+	if (msc->core_mcc != -1)
+		return msc->core_mcc;
+	return msc->network->country_code;
+}
+
+static uint16_t get_lac_for_msc(struct bsc_msc_data *msc, struct gsm_bts *bts)
+{
+	if (msc->core_lac != -1)
+		return msc->core_lac;
+	return bts->location_area_code;
+}
+
+static uint16_t get_ci_for_msc(struct bsc_msc_data *msc, struct gsm_bts *bts)
+{
+	if (msc->core_ci != -1)
+		return msc->core_ci;
+	return bts->cell_identity;
+}
+
+static void bsc_maybe_lu_reject(struct gsm_subscriber_connection *conn, int con_type, int cause)
+{
+	struct msgb *msg;
+
+	/* ignore cm service request or such */
+	if (con_type != FLT_CON_TYPE_LU)
+		return;
+
+	msg = gsm48_create_loc_upd_rej(cause);
+	if (!msg) {
+		LOGP(DMM, LOGL_ERROR, "Failed to create msg for LOCATION UPDATING REJECT.\n");
+		return;
+	}
+
+	msg->lchan = conn->lchan;
+	gsm0808_submit_dtap(conn, msg, 0, 0);
+}
+
+static int bsc_filter_initial(struct osmo_bsc_data *bsc,
+				struct bsc_msc_data *msc,
+				struct gsm_subscriber_connection *conn,
+				struct msgb *msg, char **imsi, int *con_type,
+				int *lu_cause)
+{
+	struct bsc_filter_request req;
+	struct bsc_filter_reject_cause cause;
+	struct gsm48_hdr *gh = msgb_l3(msg);
+	int rc;
+
+	req.ctx = conn;
+	req.black_list = NULL;
+	req.access_lists = bsc_access_lists();
+	req.local_lst_name = msc->acc_lst_name;
+	req.global_lst_name = conn->bts->network->bsc_data->acc_lst_name;
+	req.bsc_nr = 0;
+
+	rc = bsc_msg_filter_initial(gh, msgb_l3len(msg), &req,
+				con_type, imsi, &cause);
+	*lu_cause = cause.lu_reject_cause;
+	return rc;
+}
+
+static int bsc_filter_data(struct gsm_subscriber_connection *conn,
+				struct msgb *msg, int *lu_cause)
+{
+	struct bsc_filter_request req;
+	struct gsm48_hdr *gh = msgb_l3(msg);
+	struct bsc_filter_reject_cause cause;
+	int rc;
+
+	req.ctx = conn;
+	req.black_list = NULL;
+	req.access_lists = bsc_access_lists();
+	req.local_lst_name = conn->sccp_con->msc->acc_lst_name;
+	req.global_lst_name = conn->bts->network->bsc_data->acc_lst_name;
+	req.bsc_nr = 0;
+
+	rc = bsc_msg_filter_data(gh, msgb_l3len(msg), &req,
+				&conn->sccp_con->filter_state,
+				&cause);
+	*lu_cause = cause.lu_reject_cause;
+	return rc;
+}
+
+static void bsc_sapi_n_reject(struct gsm_subscriber_connection *conn, int dlci)
+{
+	struct msgb *resp;
+	return_when_not_connected(conn);
+
+	LOGP(DMSC, LOGL_NOTICE, "Tx MSC SAPI N REJECT DLCI=0x%02x\n", dlci);
+
+	resp = gsm0808_create_sapi_reject(dlci);
+	queue_msg_or_return(resp);
+}
+
+static void bsc_cipher_mode_compl(struct gsm_subscriber_connection *conn,
+				  struct msgb *msg, uint8_t chosen_encr)
+{
+	struct msgb *resp;
+	return_when_not_connected(conn);
+
+	LOGP(DMSC, LOGL_DEBUG, "CIPHER MODE COMPLETE from MS, forwarding to MSC\n");
+	resp = gsm0808_create_cipher_complete(msg, chosen_encr);
+	queue_msg_or_return(resp);
+}
+
+static void bsc_send_ussd_no_srv(struct gsm_subscriber_connection *conn,
+				 struct msgb *msg, const char *text)
+{
+	struct gsm48_hdr *gh;
+	int8_t pdisc;
+	uint8_t mtype;
+	int drop_message = 1;
+
+	if (!text)
+		return;
+
+	if (!msg || msgb_l3len(msg) < sizeof(*gh))
+		return;
+
+	gh = msgb_l3(msg);
+	pdisc = gsm48_hdr_pdisc(gh);
+	mtype = gsm48_hdr_msg_type(gh);
+
+	/* Is CM service request? */
+	if (pdisc == GSM48_PDISC_MM && mtype == GSM48_MT_MM_CM_SERV_REQ) {
+		struct gsm48_service_request *cm;
+
+		cm = (struct gsm48_service_request *) &gh->data[0];
+
+		/* Is type SMS or call? */
+		if (cm->cm_service_type == GSM48_CMSERV_SMS)
+			drop_message = 0;
+		else if (cm->cm_service_type == GSM48_CMSERV_MO_CALL_PACKET)
+			drop_message = 0;
+	}
+
+	if (drop_message) {
+		LOGP(DMSC, LOGL_DEBUG, "Skipping (not sending) USSD message: '%s'\n", text);
+		return;
+	}
+
+	LOGP(DMSC, LOGL_INFO, "Sending CM Service Accept\n");
+	gsm48_tx_mm_serv_ack(conn);
+
+	LOGP(DMSC, LOGL_INFO, "Sending USSD message: '%s'\n", text);
+	bsc_send_ussd_notify(conn, 1, text);
+	bsc_send_ussd_release_complete(conn);
+}
+
+/*
+ * Instruct to reserve data for a new connectiom, create the complete
+ * layer three message, send it to open the connection.
+ */
+static int bsc_compl_l3(struct gsm_subscriber_connection *conn, struct msgb *msg,
+			uint16_t chosen_channel)
+{
+	struct bsc_msc_data *msc;
+
+	LOGP(DMSC, LOGL_INFO, "Tx MSC COMPL L3\n");
+
+	/* find the MSC link we want to use */
+	msc = bsc_find_msc(conn, msg);
+	if (!msc) {
+		LOGP(DMSC, LOGL_ERROR, "Failed to find a MSC for a connection.\n");
+		bsc_send_ussd_no_srv(conn, msg,
+				     conn->bts->network->bsc_data->ussd_no_msc_txt);
+		return -1;
+	}
+
+	return complete_layer3(conn, msg, msc);
+}
+
+static int complete_layer3(struct gsm_subscriber_connection *conn,
+			   struct msgb *msg, struct bsc_msc_data *msc)
+{
+	int con_type, rc, lu_cause;
+	char *imsi = NULL;
+	struct timeval tv;
+	struct msgb *resp;
+	uint16_t network_code;
+	uint16_t country_code;
+	uint16_t lac;
+	uint16_t ci;
+	enum bsc_con ret;
+	int send_ping = msc->advanced_ping;
+
+	/* Advanced ping/pong handling */
+	if (osmo_timer_pending(&msc->pong_timer))
+		send_ping = 0;
+	if (msc->ping_timeout <= 0)
+		send_ping = 0;
+	if (send_ping && osmo_timer_remaining(&msc->ping_timer, NULL, &tv) == -1)
+		send_ping = 0;
+
+	/* Check the filter */
+	rc = bsc_filter_initial(msc->network->bsc_data, msc, conn, msg,
+				&imsi, &con_type, &lu_cause);
+	if (rc < 0) {
+		bsc_maybe_lu_reject(conn, con_type, lu_cause);
+		return BSC_API_CONN_POL_REJECT;
+	}
+
+	/* allocate resource for a new connection */
+	ret = bsc_create_new_connection(conn, msc, send_ping);
+
+	if (ret != BSC_CON_SUCCESS) {
+		/* allocation has failed */
+		if (ret == BSC_CON_REJECT_NO_LINK)
+			bsc_send_ussd_no_srv(conn, msg, msc->ussd_msc_lost_txt);
+		else if (ret == BSC_CON_REJECT_RF_GRACE)
+			bsc_send_ussd_no_srv(conn, msg, msc->ussd_grace_txt);
+
+		return BSC_API_CONN_POL_REJECT;
+	}
+
+	if (imsi)
+		conn->sccp_con->filter_state.imsi = talloc_steal(conn, imsi);
+	conn->sccp_con->filter_state.con_type = con_type;
+
+	/* check return value, if failed check msg for and send USSD */
+
+	network_code = get_network_code_for_msc(conn->sccp_con->msc);
+	country_code = get_country_code_for_msc(conn->sccp_con->msc);
+	lac = get_lac_for_msc(conn->sccp_con->msc, conn->bts);
+	ci = get_ci_for_msc(conn->sccp_con->msc, conn->bts);
+
+	bsc_scan_bts_msg(conn, msg);
+
+	resp = gsm0808_create_layer3(msg, network_code, country_code, lac, ci);
+	if (!resp) {
+		LOGP(DMSC, LOGL_DEBUG, "Failed to create layer3 message.\n");
+		sccp_connection_free(conn->sccp_con->sccp);
+		bsc_delete_connection(conn->sccp_con);
+		return BSC_API_CONN_POL_REJECT;
+	}
+
+	if (bsc_open_connection(conn->sccp_con, resp) != 0) {
+		sccp_connection_free(conn->sccp_con->sccp);
+		bsc_delete_connection(conn->sccp_con);
+		msgb_free(resp);
+		return BSC_API_CONN_POL_REJECT;
+	}
+
+	return BSC_API_CONN_POL_ACCEPT;
+}
+
+/*
+ * Plastic surgery... we want to give up the current connection
+ */
+static int move_to_msc(struct gsm_subscriber_connection *_conn,
+		       struct msgb *msg, struct bsc_msc_data *msc)
+{
+	struct osmo_bsc_sccp_con *old_con = _conn->sccp_con;
+
+	/*
+	 * 1. Give up the old connection.
+	 * This happens by sending a clear request to the MSC,
+	 * it should end with the MSC releasing the connection.
+	 */
+	old_con->conn = NULL;
+	bsc_clear_request(_conn, 0);
+
+	/*
+	 * 2. Attempt to create a new connection to the local
+	 * MSC. If it fails the caller will need to handle this
+	 * properly.
+	 */
+	_conn->sccp_con = NULL;
+	if (complete_layer3(_conn, msg, msc) != BSC_API_CONN_POL_ACCEPT) {
+		gsm0808_clear(_conn);
+		bsc_subscr_con_free(_conn);
+		return 1;
+	}
+
+	return 2;
+}
+
+static int handle_cc_setup(struct gsm_subscriber_connection *conn,
+			   struct msgb *msg)
+{
+	struct gsm48_hdr *gh = msgb_l3(msg);
+	uint8_t pdisc = gsm48_hdr_pdisc(gh);
+	uint8_t mtype = gsm48_hdr_msg_type(gh);
+
+	struct bsc_msc_data *msc;
+	struct gsm_mncc_number called;
+	struct tlv_parsed tp;
+	unsigned payload_len;
+
+	char _dest_nr[35];
+
+	/*
+	 * Do we have a setup message here? if not return fast.
+	 */
+	if (pdisc != GSM48_PDISC_CC || mtype != GSM48_MT_CC_SETUP)
+		return 0;
+
+	payload_len = msgb_l3len(msg) - sizeof(*gh);
+
+	tlv_parse(&tp, &gsm48_att_tlvdef, gh->data, payload_len, 0, 0);
+	if (!TLVP_PRESENT(&tp, GSM48_IE_CALLED_BCD)) {
+		LOGP(DMSC, LOGL_ERROR, "Called BCD not present in setup.\n");
+		return -1;
+	}
+
+	memset(&called, 0, sizeof(called));
+	gsm48_decode_called(&called,
+			    TLVP_VAL(&tp, GSM48_IE_CALLED_BCD) - 1);
+
+	if (called.plan != 1 && called.plan != 0)
+		return 0;
+
+	if (called.plan == 1 && called.type == 1) {
+		_dest_nr[0] = _dest_nr[1] = '0';
+		memcpy(_dest_nr + 2, called.number, sizeof(called.number));
+	} else
+		memcpy(_dest_nr, called.number, sizeof(called.number));
+
+	/*
+	 * Check if the connection should be moved...
+	 */
+	llist_for_each_entry(msc, &conn->bts->network->bsc_data->mscs, entry) {
+		if (msc->type != MSC_CON_TYPE_LOCAL)
+			continue;
+		if (!msc->local_pref)
+			continue;
+		if (regexec(&msc->local_pref_reg, _dest_nr, 0, NULL, 0) != 0)
+			continue;
+
+		return move_to_msc(conn, msg, msc);
+	}
+
+	return 0;
+}
+
+
+static void bsc_dtap(struct gsm_subscriber_connection *conn, uint8_t link_id, struct msgb *msg)
+{
+	int lu_cause;
+	struct msgb *resp;
+	return_when_not_connected(conn);
+
+	LOGP(DMSC, LOGL_INFO, "Tx MSC DTAP LINK_ID=0x%02x\n", link_id);
+
+	/*
+	 * We might want to move this connection to a new MSC. Ask someone
+	 * to handle it. If it was handled we will return.
+	 */
+	if (handle_cc_setup(conn, msg) >= 1)
+		return;
+
+	/* Check the filter */
+	if (bsc_filter_data(conn, msg, &lu_cause) < 0) {
+		bsc_maybe_lu_reject(conn,
+					conn->sccp_con->filter_state.con_type,
+					lu_cause);
+		bsc_clear_request(conn, 0);
+		return;
+	}
+
+	bsc_scan_bts_msg(conn, msg);
+
+	resp = gsm0808_create_dtap(msg, link_id);
+	queue_msg_or_return(resp);
+}
+
+static void bsc_assign_compl(struct gsm_subscriber_connection *conn, uint8_t rr_cause,
+			     uint8_t chosen_channel, uint8_t encr_alg_id,
+			     uint8_t speech_model)
+{
+	struct msgb *resp;
+	return_when_not_connected(conn);
+
+	LOGP(DMSC, LOGL_INFO, "Tx MSC ASSIGN COMPL\n");
+
+	resp = gsm0808_create_assignment_completed(rr_cause, chosen_channel,
+						   encr_alg_id, speech_model);
+	queue_msg_or_return(resp);
+}
+
+static void bsc_assign_fail(struct gsm_subscriber_connection *conn,
+			    uint8_t cause, uint8_t *rr_cause)
+{
+	struct msgb *resp;
+	return_when_not_connected(conn);
+
+	LOGP(DMSC, LOGL_INFO, "Tx MSC ASSIGN FAIL\n");
+
+	resp = gsm0808_create_assignment_failure(cause, rr_cause);
+	queue_msg_or_return(resp);
+}
+
+static int bsc_clear_request(struct gsm_subscriber_connection *conn, uint32_t cause)
+{
+	struct osmo_bsc_sccp_con *sccp;
+	struct msgb *resp;
+	return_when_not_connected_val(conn, 1);
+
+	LOGP(DMSC, LOGL_INFO, "Tx MSC CLEAR REQUEST\n");
+
+	/*
+	 * Remove the connection from BSC<->SCCP part, the SCCP part
+	 * will either be cleared by channel release or MSC disconnect
+	 */
+	sccp = conn->sccp_con;
+	sccp->conn = NULL;
+	conn->sccp_con = NULL;
+
+	resp = gsm0808_create_clear_rqst(GSM0808_CAUSE_RADIO_INTERFACE_FAILURE);
+	if (!resp) {
+		LOGP(DMSC, LOGL_ERROR, "Failed to allocate response.\n");
+		return 1;
+	}
+
+	bsc_queue_for_msc(sccp, resp);
+	return 1;
+}
+
+static void bsc_cm_update(struct gsm_subscriber_connection *conn,
+			  const uint8_t *cm2, uint8_t cm2_len,
+			  const uint8_t *cm3, uint8_t cm3_len)
+{
+	struct msgb *resp;
+	return_when_not_connected(conn);
+
+	resp = gsm0808_create_classmark_update(cm2, cm2_len, cm3, cm3_len);
+
+	queue_msg_or_return(resp);
+}
+
+static void bsc_mr_config(struct gsm_subscriber_connection *conn,
+				struct gsm_lchan *lchan, int full_rate)
+{
+	struct bsc_msc_data *msc;
+	struct gsm48_multi_rate_conf *ms_conf, *bts_conf;
+
+	if (!conn->sccp_con) {
+		LOGP(DMSC, LOGL_ERROR,
+		     "No msc data available on conn %p. Audio will be broken.\n",
+		     conn);
+		return;
+	}
+
+	msc = conn->sccp_con->msc;
+
+	/* initialize the data structure */
+	lchan->mr_ms_lv[0] = sizeof(*ms_conf);
+	lchan->mr_bts_lv[0] = sizeof(*bts_conf);
+	ms_conf = (struct gsm48_multi_rate_conf *) &lchan->mr_ms_lv[1];
+	bts_conf = (struct gsm48_multi_rate_conf *) &lchan->mr_bts_lv[1];
+	memset(ms_conf, 0, sizeof(*ms_conf));
+	memset(bts_conf, 0, sizeof(*bts_conf));
+
+	bts_conf->ver = ms_conf->ver = 1;
+	bts_conf->icmi = ms_conf->icmi = 1;
+
+	/* maybe gcc see's it is copy of _one_ byte */
+	bts_conf->m4_75 = ms_conf->m4_75 = msc->amr_conf.m4_75;
+	bts_conf->m5_15 = ms_conf->m5_15 = msc->amr_conf.m5_15;
+	bts_conf->m5_90 = ms_conf->m5_90 = msc->amr_conf.m5_90;
+	bts_conf->m6_70 = ms_conf->m6_70 = msc->amr_conf.m6_70;
+	bts_conf->m7_40 = ms_conf->m7_40 = msc->amr_conf.m7_40;
+	bts_conf->m7_95 = ms_conf->m7_95 = msc->amr_conf.m7_95;
+	if (full_rate) {
+		bts_conf->m10_2 = ms_conf->m10_2 = msc->amr_conf.m10_2;
+		bts_conf->m12_2 = ms_conf->m12_2 = msc->amr_conf.m12_2;
+	}
+
+	/* now copy this into the bts structure */
+	memcpy(lchan->mr_bts_lv, lchan->mr_ms_lv, sizeof(lchan->mr_ms_lv));
+}
+
+static struct bsc_api bsc_handler = {
+	.sapi_n_reject = bsc_sapi_n_reject,
+	.cipher_mode_compl = bsc_cipher_mode_compl,
+	.compl_l3 = bsc_compl_l3,
+	.dtap  = bsc_dtap,
+	.assign_compl = bsc_assign_compl,
+	.assign_fail = bsc_assign_fail,
+	.clear_request = bsc_clear_request,
+	.classmark_chg = bsc_cm_update,
+	.mr_config = bsc_mr_config,
+};
+
+struct bsc_api *osmo_bsc_api()
+{
+	return &bsc_handler;
+}