Add SGs Interface

Add an SGs interface (3GPP TS 29.118) to osmo-msc in order to support
SMS tunneling and Circuit Switched Fallback (CSFB)

Change-Id: I73359925fc1ca72b33a1466e6ac41307f2f0b11d
Related: OS#3615

1 files changed, 87 insertions, 0 deletions

diff --git a/include/osmocom/msc/sgs_iface.h b/include/osmocom/msc/sgs_iface.h
new file mode 100644
index 000000000..a167cd6d8
--- /dev/null
+++ b/include/osmocom/msc/sgs_iface.h
@@ -0,0 +1,87 @@
+/* (C) 2018-2019 by sysmocom s.f.m.c. GmbH
+ * All Rights Reserved
+ *
+ * Author: Harald Welte, Philipp Maier
+ *
+ * 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/>.
+ *
+ */
+
+#pragma once
+
+#include <osmocom/gsm/protocol/gsm_23_003.h>
+#include <osmocom/gsm/protocol/gsm_29_118.h>
+#include <osmocom/msc/vlr.h>
+#include <osmocom/msc/vlr_sgs.h>
+#include <osmocom/core/socket.h>
+
+static const unsigned int sgs_state_timer_defaults[_NUM_SGS_STATE_TIMERS] = {
+	[SGS_STATE_TS5] = SGS_TS5_DEFAULT,
+	[SGS_STATE_TS6_2] = SGS_TS6_2_DEFAULT,
+	[SGS_STATE_TS7] = SGS_TS7_DEFAULT,
+	[SGS_STATE_TS11] = SGS_TS11_DEFAULT,
+	[SGS_STATE_TS14] = SGS_TS14_DEFAULT,
+	[SGS_STATE_TS15] = SGS_TS15_DEFAULT,
+};
+
+static const unsigned int sgs_state_counter_defaults[_NUM_SGS_STATE_COUNTERS] = {
+	[SGS_STATE_NS7] = SGS_NS7_DEFAULT,
+	[SGS_STATE_NS11] = SGS_NS11_DEFAULT,
+};
+
+struct sgs_connection {
+	/* global list of SGs connections */
+	struct llist_head entry;
+
+	/* back-pointer */
+	struct sgs_state *sgs;
+
+	/* Socket name from osmo_sock_get_name() */
+	char sockname[OSMO_SOCK_NAME_MAXLEN];
+
+	/* MME for this connection, if any.  This field is NULL until we
+	 * receive the first "MME name" IE from the MME, which could be part
+	 * of the RESET procedure, but also just a normal LU request. */
+	struct sgs_mme_ctx *mme;
+
+	/* represents the SCTP connection we accept()ed from this MME */
+	struct osmo_stream_srv *srv;
+};
+
+struct sgs_mme_ctx {
+	/* global list of MME contexts */
+	struct llist_head entry;
+
+	/* back-pointer */
+	struct sgs_state *sgs;
+
+	/* MME name as string representation */
+	char fqdn[GSM23003_MME_DOMAIN_LEN + 1];
+
+	/* current connection for this MME, if any. Can be NULL if the SCTP
+	 * connection to the MME was lost and hasn't been re-established yet */
+	struct sgs_connection *conn;
+
+	/* FSM for the "VLR reset" procedure" */
+	struct osmo_fsm_inst *fi;
+	unsigned int ns11_remaining;
+};
+
+extern struct sgs_state *g_sgs;
+
+struct sgs_state *sgs_iface_init(void *ctx, struct gsm_network *network);
+int sgs_iface_rx(struct sgs_connection *sgc, struct msgb *msg);
+int sgs_iface_tx_paging(struct vlr_subscr *vsub, enum sgsap_service_ind serv_ind);
+int sgs_iface_tx_dtap_ud(struct msgb *msg);
+void sgs_iface_tx_release(struct ran_conn *conn);