ASCI: Add processing and FSMs for VGCS/VBS

Change-Id: Id9e94fb4f27bb438b7093c031344a3400bfa34f1
Related: OS#4852

3 files changed, 176 insertions, 0 deletions

diff --git a/include/osmocom/bsc/Makefile.am b/include/osmocom/bsc/Makefile.am
index 8baff9cb4..2010d6ba9 100644
--- a/include/osmocom/bsc/Makefile.am
+++ b/include/osmocom/bsc/Makefile.am
@@ -67,4 +67,5 @@ noinst_HEADERS = \
 	osmo_bsc_lcls.h \
 	smscb.h \
 	power_control.h \
+	vgcs_fsm.h \
 	$(NULL)
diff --git a/include/osmocom/bsc/gsm_data.h b/include/osmocom/bsc/gsm_data.h
index c2bd7adc0..70be943c6 100644
--- a/include/osmocom/bsc/gsm_data.h
+++ b/include/osmocom/bsc/gsm_data.h
@@ -412,6 +412,60 @@ struct gsm_subscriber_connection {
 	} fast_return;
 
 	enum gsm0808_cause clear_cause;
+
+	/* VGCS/VBS "call controling" connection */
+	struct {
+		/* Features supported by MSC/BSC */
+		bool ff_present;
+		struct gsm0808_vgcs_feature_flags ff;
+		/* Group Call Reference IE */
+		struct gsm0808_group_callref gc_ie;
+		enum gsm0808_service_flag sf;
+		uint32_t call_ref;
+		/* Call (BSC) FSM */
+		struct osmo_fsm_inst *fi;
+		/* Current talker */
+		struct gsm_subscriber_connection *talker;
+		/* L3 info of link establihment (Talker established) */
+		struct llist_head l3_queue;
+		/* Flag and cause (Talker released) */
+		bool talker_rel;
+		uint8_t talker_cause;
+		/* Flag that states acknowledgement of the talker by MSC */
+		bool msc_ack;
+		/* List of VGCS/VBS "resource controling" connections */
+		struct llist_head chan_list;
+	} vgcs_call;
+
+	/* VGCS/VBS "resource controling" connection */
+	struct {
+		/* List entry of chan_list of "call controling" connection */
+		struct llist_head list;
+		/* Group Call Reference IE */
+		struct gsm0808_group_callref gc_ie;
+		enum gsm0808_service_flag sf;
+		uint32_t call_ref;
+		/* Channel type IE */
+		struct gsm0808_channel_type ct;
+		/* Channel mode and rate */
+		struct channel_mode_and_rate ch_mode_rate;
+		/* Cell Identifier IE */
+		struct gsm0808_cell_id ci;
+		char ci_str[16];
+		/* Assignment Requirements IE */
+		enum gsm0808_assignment_requirement ar;
+		/* Call Identifier IE */
+		uint32_t call_id;
+		/* Pointer to VGCS/VBS "call controling" gsconn */
+		struct gsm_subscriber_connection *call;
+		/* Cell (BTS) FSM */
+		struct osmo_fsm_inst *fi;
+		/* lchan to be assigned */
+		struct gsm_lchan *new_lchan;
+		/* MGW peer */
+		char msc_rtp_addr[INET6_ADDRSTRLEN];
+		uint16_t msc_rtp_port;
+	} vgcs_chan;
 };
 
 
diff --git a/include/osmocom/bsc/vgcs_fsm.h b/include/osmocom/bsc/vgcs_fsm.h
new file mode 100644
index 000000000..80ea21fd0
--- /dev/null
+++ b/include/osmocom/bsc/vgcs_fsm.h
@@ -0,0 +1,121 @@
+/* Handle a call via VGCS/VBCS (Voice Group/Broadcast Call Service). */
+/*
+ * (C) 2023 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+ * All Rights Reserved
+ *
+ * SPDX-License-Identifier: AGPL-3.0+
+ *
+ * Author: Andreas Eversberg
+ *
+ * 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
+
+/* Events for both VGCS/VBS state machines. */
+enum vgcs_fsm_event {
+	/* The BSC sets up a VGCS/VBS call. */
+	VGCS_EV_SETUP,
+	/* The BSC wants to assign a VGCS/VBS channel. */
+	VGCS_EV_ASSIGN_REQ,
+	/* The BTS detects a talker on a channel. */
+	VGCS_EV_TALKER_DET,
+	/* The BTS detects a listener on a channel. */
+	VGCS_EV_LISTENER_DET,
+	/* The MSC accepts a talker. */
+	VGCS_EV_MSC_ACK,
+	/* The MSC rejects a talker. */
+	VGCS_EV_MSC_REJECT,
+	/* The MSC seizes all channels. (blocking for calls) */
+	VGCS_EV_MSC_SEIZE,
+	/* The MSC releases all channels. (unblocking for calls) */
+	VGCS_EV_MSC_RELEASE,
+	/* The MSC sends message to talker. (E.g. CONNECT) */
+	VGCS_EV_MSC_DTAP,
+	/* Channel is now active. Waiting for Talker. */
+	VGCS_EV_LCHAN_ACTIVE,
+	/* Channel activation error. */
+	VGCS_EV_LCHAN_ERROR,
+	/* MGW connection is now active. Waiting for Talker. */
+	VGCS_EV_MGW_OK,
+	/* MGW connection error. */
+	VGCS_EV_MGW_FAIL,
+	/* Channel link established. (Talker establised.) */
+	VGCS_EV_TALKER_EST,
+	/* Channel link data. (Talker sends data.) */
+	VGCS_EV_TALKER_DATA,
+	/* Channel link released. (Talker released.) */
+	VGCS_EV_TALKER_REL,
+	/* Channel link failed. (Talker failed.) */
+	VGCS_EV_TALKER_FAIL,
+	/* Channel is blocked by BSC. */
+	VGCS_EV_BLOCK,
+	/* Channel is rejected by BSC. */
+	VGCS_EV_REJECT,
+	/* Channel is unblocked by BSC. */
+	VGCS_EV_UNBLOCK,
+	/* The connection will be destroyed. (free VGCS resources) */
+	VGCS_EV_CLEANUP,
+	/* The calling subscriber has been assigned to the group channel. */
+	VGCS_EV_CALLING_ASSIGNED,
+};
+
+
+/* States of the VGCS/VBS call state machine */
+enum vgcs_call_fsm_state {
+	/* Call is not setup. Initial state when instance is created. */
+	VGCS_CALL_ST_NULL = 0,
+	/* Call is idle. */
+	VGCS_CALL_ST_IDLE,
+	/* Call is busy, due to a talker in this BSC. */
+	VGCS_CALL_ST_BUSY,
+	/* Call is blocked, due to a talker in a different BSC. */
+	VGCS_CALL_ST_BLOCKED,
+};
+
+/* States of the VGCS/VBS channel state machine */
+enum vgcs_chan_fsm_state {
+	/* Channel not assigned. Initial state when instance is created. */
+	VGCS_CHAN_ST_NULL = 0,
+	/* Wait for establishment of VGCS/VBS channel at BTS. */
+	VGCS_CHAN_ST_WAIT_EST,
+	/* Channel active and idle. Channel is marked as uplink busy. */
+	VGCS_CHAN_ST_ACTIVE_BLOCKED,
+	/* Channel active and idle. Channel is marked as uplink free. */
+	VGCS_CHAN_ST_ACTIVE_FREE,
+	/* Channel active and talker was detected, L2 must be established. */
+	VGCS_CHAN_ST_ACTIVE_INIT,
+	/* Channel active and talker established L2. */
+	VGCS_CHAN_ST_ACTIVE_EST,
+	/* Channel active and wait for talker to release L2. */
+	VGCS_CHAN_ST_ACTIVE_REL,
+};
+
+int vgcs_vbs_chan_start(struct gsm_subscriber_connection *conn, struct msgb *msg);
+int vgcs_vbs_call_start(struct gsm_subscriber_connection *conn, struct msgb *msg);
+
+int bssmap_handle_ass_req_ct_speech(struct gsm_subscriber_connection *conn, struct gsm_bts *bts,
+				    struct tlv_parsed *tp, struct gsm0808_channel_type *ct,
+				    struct assignment_request *req, uint8_t *cause);
+void bsc_tx_setup_ack(struct gsm_subscriber_connection *conn, struct gsm0808_vgcs_feature_flags *ff);
+void bsc_tx_setup_refuse(struct gsm_subscriber_connection *conn, uint8_t cause);
+void bsc_tx_vgcs_vbs_assignment_result(struct gsm_subscriber_connection *conn, struct gsm0808_channel_type *ct,
+				       struct gsm0808_cell_id *ci, uint32_t call_id);
+void bsc_tx_vgcs_vbs_assignment_fail(struct gsm_subscriber_connection *conn, uint8_t cause);
+void bsc_tx_uplink_req(struct gsm_subscriber_connection *conn);
+void bsc_tx_uplink_req_conf(struct gsm_subscriber_connection *conn, struct gsm0808_cell_id *ci, uint8_t *l3_info,
+			    uint8_t length);
+void bsc_tx_uplink_app_data(struct gsm_subscriber_connection *conn, struct gsm0808_cell_id *ci, uint8_t *l3_info,
+			    uint8_t length);
+void bsc_tx_uplink_release_ind(struct gsm_subscriber_connection *conn, uint8_t cause);
+struct gsm_lchan *vgcs_vbs_find_lchan(struct gsm_bts *bts, struct gsm0808_group_callref *gc);