1 files changed, 328 insertions, 0 deletions

diff --git a/src/osmo-bsc/osmo_bsc_sccp.c b/src/osmo-bsc/osmo_bsc_sccp.c
new file mode 100644
index 000000000..e242390ef
--- /dev/null
+++ b/src/osmo-bsc/osmo_bsc_sccp.c
@@ -0,0 +1,328 @@
+/* Interaction with the SCCP subsystem */
+/*
+ * (C) 2009-2014 by Holger Hans Peter Freyther <zecke@selfish.org>
+ * (C) 2009-2014 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/gsm_data.h>
+#include <openbsc/osmo_bsc.h>
+#include <openbsc/osmo_bsc_grace.h>
+#include <openbsc/bsc_msc_data.h>
+#include <openbsc/gsm_04_80.h>
+#include <openbsc/debug.h>
+#include <openbsc/ipaccess.h>
+#include <openbsc/signal.h>
+
+#include <osmocom/core/talloc.h>
+#include <osmocom/gsm/gsm0808.h>
+#include <osmocom/gsm/protocol/gsm_08_08.h>
+
+#include <osmocom/sccp/sccp.h>
+
+/* SCCP helper */
+#define SCCP_IT_TIMER 60
+
+static LLIST_HEAD(active_connections);
+
+static void free_queued(struct osmo_bsc_sccp_con *conn)
+{
+	struct msgb *msg;
+
+	while (!llist_empty(&conn->sccp_queue)) {
+		/* this is not allowed to fail */
+		msg = msgb_dequeue(&conn->sccp_queue);
+		msgb_free(msg);
+	}
+
+	conn->sccp_queue_size = 0;
+}
+
+static void send_queued(struct osmo_bsc_sccp_con *conn)
+{
+	struct msgb *msg;
+
+	while (!llist_empty(&conn->sccp_queue)) {
+		/* this is not allowed to fail */
+		msg = msgb_dequeue(&conn->sccp_queue);
+		sccp_connection_write(conn->sccp, msg);
+		msgb_free(msg);
+		conn->sccp_queue_size -= 1;
+	}
+}
+
+static void msc_outgoing_sccp_data(struct sccp_connection *conn,
+				   struct msgb *msg, unsigned int len)
+{
+	struct osmo_bsc_sccp_con *bsc_con =
+			(struct osmo_bsc_sccp_con *) conn->data_ctx;
+
+	bsc_handle_dt1(bsc_con, msg, len);
+}
+
+static void msc_outgoing_sccp_state(struct sccp_connection *conn, int old_state)
+{
+	struct osmo_bsc_sccp_con *con_data;
+
+	if (conn->connection_state >= SCCP_CONNECTION_STATE_RELEASE_COMPLETE) {
+		con_data = (struct osmo_bsc_sccp_con *) conn->data_ctx;
+		if (con_data->conn) {
+			LOGP(DMSC, LOGL_ERROR,
+				"ERROR: The lchan is still associated.\n");
+			gsm0808_clear(con_data->conn);
+			bsc_subscr_con_free(con_data->conn);
+			con_data->conn = NULL;
+		}
+
+		con_data->sccp = NULL;
+		free_queued(con_data);
+		sccp_connection_free(conn);
+		bsc_delete_connection(con_data);
+	} else if (conn->connection_state == SCCP_CONNECTION_STATE_ESTABLISHED) {
+		LOGP(DMSC, LOGL_DEBUG, "Connection established: %p\n", conn);
+		con_data = (struct osmo_bsc_sccp_con *) conn->data_ctx;
+
+		osmo_timer_del(&con_data->sccp_cc_timeout);
+		osmo_timer_schedule(&con_data->sccp_it_timeout, SCCP_IT_TIMER, 0);
+
+		send_queued(con_data);
+	}
+}
+
+static void bsc_sccp_force_free(struct osmo_bsc_sccp_con *data)
+{
+	if (data->conn) {
+		gsm0808_clear(data->conn);
+		bsc_subscr_con_free(data->conn);
+		data->conn = NULL;
+	}
+
+	free_queued(data);
+	sccp_connection_force_free(data->sccp);
+	data->sccp = NULL;
+	bsc_delete_connection(data);
+}
+
+static void sccp_it_timeout(void *_data)
+{
+	struct osmo_bsc_sccp_con *data =
+		(struct osmo_bsc_sccp_con *) _data;
+
+	sccp_connection_send_it(data->sccp);
+	osmo_timer_schedule(&data->sccp_it_timeout, SCCP_IT_TIMER, 0);
+}
+
+static void sccp_cc_timeout(void *_data)
+{
+	struct osmo_bsc_sccp_con *data =
+		(struct osmo_bsc_sccp_con *) _data;
+
+	if (data->sccp->connection_state >= SCCP_CONNECTION_STATE_ESTABLISHED)
+		return;
+
+	LOGP(DMSC, LOGL_ERROR, "The connection was never established.\n");
+	bsc_sccp_force_free(data);
+}
+
+static void msc_sccp_write_ipa(struct sccp_connection *conn, struct msgb *msg,
+			      void *global_ctx, void *ctx)
+{
+	struct bsc_msc_connection *msc_con;
+
+	if (conn) {
+		struct osmo_bsc_sccp_con *bsc_con = conn->data_ctx;
+		msc_con = bsc_con->msc->msc_con;
+		if (bsc_con->send_ping) {
+			bsc_con->send_ping = 0;
+			msc_queue_write_with_ping(msc_con, msg, IPAC_PROTO_SCCP);
+			return;
+		}
+	} else {
+		msc_con = ctx;
+	}
+
+	msc_queue_write(msc_con, msg, IPAC_PROTO_SCCP);
+}
+
+static int msc_sccp_accept(struct sccp_connection *connection, void *data)
+{
+	LOGP(DMSC, LOGL_DEBUG, "Rejecting incoming SCCP connection.\n");
+	return -1;
+}
+
+static int msc_sccp_read(struct msgb *msgb, unsigned int length, void *data)
+{
+	struct bsc_msc_data *msc = (struct bsc_msc_data *) msgb->cb[0];
+	return bsc_handle_udt(msc, msgb, length);
+}
+
+int bsc_queue_for_msc(struct osmo_bsc_sccp_con *conn, struct msgb *msg)
+{
+	struct sccp_connection *sccp = conn->sccp;
+
+	if (sccp->connection_state > SCCP_CONNECTION_STATE_ESTABLISHED) {
+		LOGP(DMSC, LOGL_ERROR, "Connection closing, dropping packet on: %p\n", sccp);
+		msgb_free(msg);
+	} else if (sccp->connection_state == SCCP_CONNECTION_STATE_ESTABLISHED
+		   && conn->sccp_queue_size == 0) {
+		sccp_connection_write(sccp, msg);
+		msgb_free(msg);
+	} else if (conn->sccp_queue_size > 10) {
+		LOGP(DMSC, LOGL_ERROR, "Connection closing, dropping packet on: %p\n", sccp);
+		msgb_free(msg);
+	} else {
+		LOGP(DMSC, LOGL_DEBUG, "Queueing packet on %p. Queue size: %d\n", sccp, conn->sccp_queue_size);
+		conn->sccp_queue_size += 1;
+		msgb_enqueue(&conn->sccp_queue, msg);
+	}
+
+	return 0;
+}
+
+enum bsc_con bsc_create_new_connection(struct gsm_subscriber_connection *conn,
+			      struct bsc_msc_data *msc, int send_ping)
+{
+	struct osmo_bsc_sccp_con *bsc_con;
+	struct sccp_connection *sccp;
+
+	/* This should not trigger */
+	if (!msc || !msc->msc_con->is_authenticated) {
+		LOGP(DMSC, LOGL_ERROR,
+		     "How did this happen? MSC is not connected. Dropping.\n");
+		return BSC_CON_REJECT_NO_LINK;
+	}
+
+	if (!bsc_grace_allow_new_connection(conn->bts->network, conn->bts)) {
+		LOGP(DMSC, LOGL_NOTICE, "BSC in grace period. No new connections.\n");
+		return BSC_CON_REJECT_RF_GRACE;
+	}
+
+	sccp = sccp_connection_socket();
+	if (!sccp) {
+		LOGP(DMSC, LOGL_ERROR, "Failed to allocate memory.\n");
+		return BSC_CON_NO_MEM;
+	}
+
+	bsc_con = talloc_zero(conn->bts, struct osmo_bsc_sccp_con);
+	if (!bsc_con) {
+		LOGP(DMSC, LOGL_ERROR, "Failed to allocate.\n");
+		sccp_connection_free(sccp);
+		return BSC_CON_NO_MEM;
+	}
+
+	/* callbacks */
+	sccp->state_cb = msc_outgoing_sccp_state;
+	sccp->data_cb = msc_outgoing_sccp_data;
+	sccp->data_ctx = bsc_con;
+
+	bsc_con->send_ping = send_ping;
+
+	/* prepare the timers */
+	osmo_timer_setup(&bsc_con->sccp_it_timeout, sccp_it_timeout, bsc_con);
+	osmo_timer_setup(&bsc_con->sccp_cc_timeout, sccp_cc_timeout, bsc_con);
+
+	INIT_LLIST_HEAD(&bsc_con->sccp_queue);
+
+	bsc_con->sccp = sccp;
+	bsc_con->msc = msc;
+	bsc_con->conn = conn;
+	llist_add_tail(&bsc_con->entry, &active_connections);
+	conn->sccp_con = bsc_con;
+	return BSC_CON_SUCCESS;
+}
+
+int bsc_open_connection(struct osmo_bsc_sccp_con *conn, struct msgb *msg)
+{
+	osmo_timer_schedule(&conn->sccp_cc_timeout, 10, 0);
+	sccp_connection_connect(conn->sccp, &sccp_ssn_bssap, msg);
+	msgb_free(msg);
+	return 0;
+}
+
+int bsc_delete_connection(struct osmo_bsc_sccp_con *sccp)
+{
+	if (!sccp)
+		return 0;
+
+	if (sccp->conn)
+		LOGP(DMSC, LOGL_ERROR, "Should have been cleared.\n");
+
+	llist_del(&sccp->entry);
+	osmo_timer_del(&sccp->sccp_it_timeout);
+	osmo_timer_del(&sccp->sccp_cc_timeout);
+	talloc_free(sccp);
+	return 0;
+}
+
+static void bsc_notify_msc_lost(struct osmo_bsc_sccp_con *con)
+{
+	struct gsm_subscriber_connection *conn = con->conn;
+
+	/* send USSD notification if string configured and con->data is set */
+	if (!conn)
+		return;
+
+	/* check for config string */
+	if (!con->msc->ussd_msc_lost_txt)
+		return;
+	if (con->msc->ussd_msc_lost_txt[0] == '\0')
+		return;
+
+	/* send USSD notification */
+	bsc_send_ussd_notify(conn, 1, conn->sccp_con->msc->ussd_msc_lost_txt);
+	bsc_send_ussd_release_complete(conn);
+}
+
+static void bsc_notify_and_close_conns(struct bsc_msc_connection *msc_con)
+{
+	struct osmo_bsc_sccp_con *con, *tmp;
+
+	llist_for_each_entry_safe(con, tmp, &active_connections, entry) {
+		if (con->msc->msc_con != msc_con)
+			continue;
+
+		bsc_notify_msc_lost(con);
+		bsc_sccp_force_free(con);
+	}
+}
+
+static int handle_msc_signal(unsigned int subsys, unsigned int signal,
+			     void *handler_data, void *signal_data)
+{
+	struct msc_signal_data *msc;
+
+	if (subsys != SS_MSC)
+		return 0;
+
+	msc = signal_data;
+	if (signal == S_MSC_LOST)
+		bsc_notify_and_close_conns(msc->data->msc_con);
+
+	return 0;
+}
+
+int osmo_bsc_sccp_init(struct gsm_network *gsmnet)
+{
+	sccp_set_log_area(DSCCP);
+	sccp_system_init(msc_sccp_write_ipa, gsmnet);
+	sccp_connection_set_incoming(&sccp_ssn_bssap, msc_sccp_accept, NULL);
+	sccp_set_read(&sccp_ssn_bssap, msc_sccp_read, gsmnet);
+
+	osmo_signal_register_handler(SS_MSC, handle_msc_signal, gsmnet);
+
+	return 0;
+}