ASCI: Add call control for VGCS/VBS

Change-Id: I9947403fde8212b66758104443c60aaacc8b1e7b
Related: OS#4854

4 files changed, 257 insertions, 1 deletions

diff --git a/include/osmocom/msc/Makefile.am b/include/osmocom/msc/Makefile.am
index 3c54dee5b..9fa06eb8e 100644
--- a/include/osmocom/msc/Makefile.am
+++ b/include/osmocom/msc/Makefile.am
@@ -25,6 +25,7 @@ noinst_HEADERS = \
 	msc_a_remote.h \
 	msc_common.h \
 	msc_ho.h \
+	msc_vgcs.h \
 	msc_i.h \
 	msc_i_remote.h \
 	msc_roles.h \
diff --git a/include/osmocom/msc/msc_vgcs.h b/include/osmocom/msc/msc_vgcs.h
new file mode 100644
index 000000000..2b2f45d31
--- /dev/null
+++ b/include/osmocom/msc/msc_vgcs.h
@@ -0,0 +1,228 @@
+/* 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
+
+#include <osmocom/msc/transaction.h>
+
+#define GSM44068_ALLOC_SIZE        2048
+#define GSM44068_ALLOC_HEADROOM    256
+
+static inline struct msgb *gsm44068_msgb_alloc_name(const char *name)
+{
+	return msgb_alloc_headroom(GSM44068_ALLOC_SIZE, GSM44068_ALLOC_HEADROOM, name);
+}
+
+/* VGCS/VBS "call control" connection to each BSS */
+struct vgcs_bss {
+	struct llist_head list;		/* List entry */
+	struct llist_head cell_list;	/* List of cells */
+	struct gsm_trans *trans;	/* Back pointer to transaction */
+	struct osmo_fsm_inst *fi;	/* State machine of each BSS */
+	struct ran_conn *conn;		/* RAN ("SCCP") connection */
+	enum trans_type trans_type;	/* Transaction type */
+	uint32_t callref;		/* Callref */
+	int pc;				/* Point code for debug purpose */
+};
+
+/* VGCS/VBS "resource control" connection to each cell in BSS */
+struct vgcs_bss_cell {
+	struct llist_head list_bss;	/* List entry in vgcs_bss */
+	struct llist_head list_mgw;	/* List entry in MGW endpoint */
+	struct vgcs_bss *bss;		/* Back pointer to vgcs_bss */
+	struct vgcs_mgw_ep *mgw;	/* Back pointer to vgcs_mgw_ep */
+	struct osmo_fsm_inst *fi;	/* State machine of each cell */
+	int cell_id;			/* Id of cell (BTS) to use */
+	struct ran_conn *conn;		/* RAN ("SCCP") connection */
+	enum trans_type trans_type;	/* Transaction type */
+	uint32_t callref;		/* Callref */
+	int call_id;			/* Id of call (used for MGW connections) */
+	int pc;				/* Point code for debug purpose */
+	bool assigned;			/* Flags if assignment is complete */
+	struct rtp_stream *rtps;	/* MGW connection process */
+};
+
+/* VGCS/VBS MGW endpoint for each call */
+struct vgcs_mgw_ep {
+	struct llist_head cell_list;	/* List of cells with connections */
+	struct llist_head list;		/* List entry */
+	struct osmo_fsm_inst *fi;	/* State machine of each cell */
+	struct osmo_mgcpc_ep *mgw_ep;	/* MGW endpoint */
+};
+
+/* Events for the GCC/BCC state machine.
+ * There is no primitive definition like MNGCC-* oder MNBCC-* in the standard. */
+enum vgcs_gcc_fsm_event {
+	/* The network sets up a call. */
+	VGCS_GCC_EV_NET_SETUP,
+	/* The network requests termination. */
+	VGCS_GCC_EV_NET_TERM,
+	/* The user sets up a call. */
+	VGCS_GCC_EV_USER_SETUP,
+	/* The user requests termination. */
+	VGCS_GCC_EV_USER_TERM,
+	/* BSS completed call establishment (all BSCs) */
+	VGCS_GCC_EV_BSS_ESTABLISHED,
+	/* Assignment was completed. */
+	VGCS_GCC_EV_BSS_ASSIGN_CPL,
+	/* Assignment failed. */
+	VGCS_GCC_EV_BSS_ASSIGN_FAIL,
+	/* BSS released call establishment (all BSCs) */
+	VGCS_GCC_EV_BSS_RELEASED,
+	/* Inactivity timeout */
+	VGCS_GCC_EV_TIMEOUT,
+};
+
+/* 3GPP TS 44.068 6.1.2.2 States of GCC/BCC */
+enum vgcs_gcc_fsm_state {
+	/* No call. Initial state when instance is created. */
+	VGCS_GCC_ST_N0_NULL = 0,
+	/* An MS wants to establish a call. */
+	VGCS_GCC_ST_N1_CALL_INITIATED,
+	/* Call established in at least one cell. */
+	VGCS_GCC_ST_N2_CALL_ACTIVE,
+	/* Channel activation is requested, CONNECT already sent to MS. */
+	VGCS_GCC_ST_N3_CALL_EST_PROC,
+	/* Call termination is requested, waiting for all cells to confirm. */
+	VGCS_GCC_ST_N4_TERMINATION_REQ,
+};
+
+const char *vgcs_bcc_gcc_state_name(struct osmo_fsm_inst *fi);
+
+/* Events for the VGCS/VBS "call control" state machine */
+enum vgcs_bss_fsm_event {
+	/* Start a VGCS/VBS call using VGCS/VBS SETUP message */
+	VGCS_BSS_EV_SETUP,
+	/* VGCS/VBS SETUP ACK is received */
+	VGCS_BSS_EV_SETUP_ACK,
+	/* VGCS/VBS SETUP REFUSE is received */
+	VGCS_BSS_EV_SETUP_REFUSE,
+	/* VGCS/VBS ASSIGNMENT complete or failed */
+	VGCS_BSS_EV_ACTIVE_OR_FAIL,
+	/* Talker request */
+	VGCS_BSS_EV_UL_REQUEST,
+	/* Talker established uplink */
+	VGCS_BSS_EV_UL_REQUEST_CNF,
+	/* Talker send app data */
+	VGCS_BSS_EV_UL_APP_DATA,
+	/* Talker send signaling data */
+	VGCS_BSS_EV_BSS_DTAP,
+	/* Talker becomes listener */
+	VGCS_BSS_EV_UL_RELEASE,
+	/* Release channel towards BSS */
+	VGCS_BSS_EV_CLEAR,
+	/* Channel closed from BSS */
+	VGCS_BSS_EV_CLOSE,
+	/* Release is complete */
+	VGCS_BSS_EV_RELEASED,
+};
+
+/* States of the VGCS/VBS "call control" state machine */
+enum vgcs_bss_fsm_state {
+	/* No call. Initial state when instance is created. */
+	VGCS_BSS_ST_NULL = 0,
+	/* VGCS/VBS SETUP is sent towards BSC */
+	VGCS_BSS_ST_SETUP,
+	/* VGCS/VBS ASSIGNMENT REQUEST is sent towards BSC */
+	VGCS_BSS_ST_ASSIGNMENT,
+	/* VGCS/VBS is establised */
+	VGCS_BSS_ST_ACTIVE,
+	/* CLEAR COMMAND was sent */
+	VGCS_BSS_ST_RELEASE,
+};
+
+/* Events for the VGCS/VBS "resource control" state machine */
+enum vgcs_cell_fsm_event {
+	/* RTP stream gone */
+	VGCS_CELL_EV_RTP_STREAM_GONE,
+	/* RTP stream remote addr available */
+	VGCS_CELL_EV_RTP_STREAM_ADDR_AVAILABLE,
+	/* RTP stream established */
+	VGCS_CELL_EV_RTP_STREAM_ESTABLISHED,
+	/* Start a VGCS/VBS channel using VGCS/VBS ASSIGNMENT message */
+	VGCS_CELL_EV_ASSIGN,
+	/* VGCS/VBS ASSIGNMENT RESULT is received */
+	VGCS_CELL_EV_ASSIGN_RES,
+	/* VGCS/VBS ASSIGNMENT FAILURE is received */
+	VGCS_CELL_EV_ASSIGN_FAIL,
+	/* Release channel towards BSS */
+	VGCS_CELL_EV_CLEAR,
+	/* Channel closed from BSS */
+	VGCS_CELL_EV_CLOSE,
+	/* Release is complete */
+	VGCS_CELL_EV_RELEASED,
+};
+
+/* States of the VGCS/VBS "resource control" state machine */
+enum vgcs_cell_fsm_state {
+	/* No call. Initial state when instance is created. */
+	VGCS_CELL_ST_NULL = 0,
+	/* VGCS/VBS ASSIGNMENT REQUEST is sent towards BSC */
+	VGCS_CELL_ST_ASSIGNMENT,
+	/* Channel is establised */
+	VGCS_CELL_ST_ACTIVE,
+	/* CLEAR COMMAND was sent */
+	VGCS_CELL_ST_RELEASE,
+};
+
+/* Events for the VGCS/VBS MGW endpoint state machine */
+enum vgcs_mgw_ep_fsm_event {
+	/* MGW endpoint gone */
+	VGCS_MGW_EP_EV_FREE,
+	/* Destroy MGW endpoint */
+	VGCS_MGW_EP_EV_CLEAR,
+};
+
+/* States of the VGCS/VBS MGW endpoint state machine */
+enum vgcs_mgw_ep_fsm_state {
+	VGCS_MGW_EP_ST_NULL = 0,
+	/* MGW endpoint allocated */
+	VGCS_MGW_EP_ST_ACTIVE,
+};
+
+const char *gsm44068_group_id_string(uint32_t callref);
+
+struct gcr;
+
+int gsm44068_rcv_rr(struct msc_a *msc_a, struct msgb *msg);
+int gsm44068_rcv_bcc_gcc(struct msc_a *msc_a, struct gsm_trans *trans, struct msgb *msg);
+const char *vgcs_vty_initiate(struct gsm_network *gsmnet, struct gcr *gcr);
+const char *vgcs_vty_terminate(struct gsm_network *gsmnet, struct gcr *gcr);
+void gsm44068_bcc_gcc_trans_free(struct gsm_trans *trans);
+
+void vgcs_vbs_setup_ack(struct vgcs_bss *bss, const struct ran_msg *ran_msg);
+void vgcs_vbs_setup_refuse(struct vgcs_bss *bss, const struct ran_msg *ran_msg);
+void vgcs_vbs_assign_result(struct vgcs_bss_cell *cell, const struct ran_msg *ran_msg);
+void vgcs_vbs_assign_fail(struct vgcs_bss_cell *cell, const struct ran_msg *ran_msg);
+void vgcs_vbs_queuing_ind(struct vgcs_bss_cell *cell);
+void vgcs_uplink_request(struct vgcs_bss *bss, const struct ran_msg *ran_msg);
+void vgcs_uplink_request_cnf(struct vgcs_bss *bss, const struct ran_msg *ran_msg);
+void vgcs_app_data(struct vgcs_bss *bss, const struct ran_msg *ran_msg);
+void vgcs_bss_dtap(struct vgcs_bss *bss, const struct ran_msg *ran_msg);
+void vgcs_uplink_release_ind(struct vgcs_bss *bss, const struct ran_msg *ran_msg);
+void vgcs_vbs_assign_status(struct vgcs_bss_cell *cell, const struct ran_msg *ran_msg);
+void vgcs_vbs_clear_req_channel(struct vgcs_bss_cell *cell, const struct ran_msg *ran_msg);
+void vgcs_vbs_clear_cpl_channel(struct vgcs_bss_cell *cell, const struct ran_msg *ran_msg);
+void vgcs_vbs_clear_req(struct vgcs_bss *bss, const struct ran_msg *ran_msg);
+void vgcs_vbs_clear_cpl(struct vgcs_bss *bss, const struct ran_msg *ran_msg);
+void vgcs_vbs_caller_assign_cpl(struct gsm_trans *trans);
+void vgcs_vbs_caller_assign_fail(struct gsm_trans *trans);
diff --git a/include/osmocom/msc/ran_conn.h b/include/osmocom/msc/ran_conn.h
index 7aa50df07..cdaa02652 100644
--- a/include/osmocom/msc/ran_conn.h
+++ b/include/osmocom/msc/ran_conn.h
@@ -18,9 +18,17 @@ struct ran_conn {
 	uint32_t sccp_conn_id;
 
 	/* MSC role that this RAN connection belongs to. This will be either an msc_i (currently active
-	 * connection) or an msc_t (transitory new connection during Handover). */
+	 * connection) or an msc_t (transitory new connection during Handover).
+	 * Used for usual L3 ran_conn to a subscriber. */
 	struct osmo_fsm_inst *msc_role;
 
+	/* For VGCS/VBS, we have additional N connections to BSS. When receiving messages for a group call peer,
+	 * dispatch to the VGCS management. */
+	struct {
+		void *bss;
+		void *cell;
+	} vgcs;
+
 	bool closing;
 };
 
diff --git a/include/osmocom/msc/transaction.h b/include/osmocom/msc/transaction.h
index 356bd6c8b..a5a2e84ea 100644
--- a/include/osmocom/msc/transaction.h
+++ b/include/osmocom/msc/transaction.h
@@ -99,6 +99,25 @@ struct gsm_trans {
 
 	union {
 		struct {
+			/* State machine of setup process towards BSS */
+			struct osmo_fsm_inst *fi;
+			/* BSS list with all VGCS/VBS calls */
+			struct llist_head bss_list;
+			/* Inactivity timeout and timer */
+			int inactivity_to;
+			struct osmo_timer_list timer_inactivity;
+			/* If talker's downlink shall be muted */
+			bool mute_talker;
+			/* Indicator, if Uplink is used in one cell */
+			bool uplink_busy;
+			/* BSS that uses the uplink */
+			struct vgcs_bss *uplink_bss;
+			/* Cell that uses the uplink */
+			struct vgcs_bss_cell *uplink_cell;
+			/* If uplink is used by the originator */
+			bool uplink_originator;
+		} gcc;
+		struct {
 
 			/* current call state */
 			int state;