ASCI: Handle rejection of voice group/broadcast call correctly

If joining a call gets rejected, the call must not be released, instead
it must return to U3 state (incoming call), because the call still
exists in the cell and it might possible to join it later.

If a call notification is gone, a new event is used in the state machine
to release incoming call.

Change-Id: I605387c6be409ef0e67caf7b9e2a83e1032b45f1
Related: OS#5364

1 files changed, 26 insertions, 12 deletions

diff --git a/src/host/layer23/src/mobile/gsm44068_gcc_bcc.c b/src/host/layer23/src/mobile/gsm44068_gcc_bcc.c
index 0cef1c3a..4fe0b822 100644
--- a/src/host/layer23/src/mobile/gsm44068_gcc_bcc.c
+++ b/src/host/layer23/src/mobile/gsm44068_gcc_bcc.c
@@ -138,10 +138,11 @@ enum vgcs_gcc_fsm_event {
 	VGCS_GCC_EV_DI_CONNECT,			/* network indicates connect */
 	VGCS_GCC_EV_TIMEOUT,			/* several timeout events */
 	VGCS_GCC_EV_SETUP_IND,			/* notification of ongoing call received */
+	VGCS_GCC_EV_REL_IND,			/* notification of call being gone */
 	VGCS_GCC_EV_JOIN_GC_REQ,		/* user wants to join ongoing call */
 	VGCS_GCC_EV_JOIN_GC_CNF,		/* MM confirms joining ongoing call */
 	VGCS_GCC_EV_ABORT_REQ,			/* user rejects or leaves call */
-	VGCS_GCC_EV_ABORT_IND,			/* MM indicates call gone / channel released or failed */
+	VGCS_GCC_EV_ABORT_IND,			/* MM indicates channel released or failed */
 	VGCS_GCC_EV_TALK_REQ,			/* user wants to talk */
 	VGCS_GCC_EV_TALK_CNF,			/* MM confirms talk */
 	VGCS_GCC_EV_TALK_REJ,			/* MM rejects talk */
@@ -162,6 +163,7 @@ static const struct value_string vgcs_gcc_fsm_event_names[] = {
 	OSMO_VALUE_STRING(VGCS_GCC_EV_DI_CONNECT),
 	OSMO_VALUE_STRING(VGCS_GCC_EV_TIMEOUT),
 	OSMO_VALUE_STRING(VGCS_GCC_EV_SETUP_IND),
+	OSMO_VALUE_STRING(VGCS_GCC_EV_REL_IND),
 	OSMO_VALUE_STRING(VGCS_GCC_EV_JOIN_GC_REQ),
 	OSMO_VALUE_STRING(VGCS_GCC_EV_JOIN_GC_CNF),
 	OSMO_VALUE_STRING(VGCS_GCC_EV_ABORT_REQ),
@@ -1104,7 +1106,7 @@ static void vgcs_gcc_fsm_u2nc_action(struct osmo_fsm_inst *fi, uint32_t event, v
 		/* Change to GROUP CALL PRESENT state. */
 		osmo_fsm_inst_state_chg(fi, VGCS_GCC_ST_U3_GROUP_CALL_PRESENT, 0, 0);
 		break;
-	case VGCS_GCC_EV_ABORT_IND:
+	case VGCS_GCC_EV_REL_IND:
 		/* The MM layer indicates that group channel is gone. */
 		LOG_GCC(trans, LOGL_INFO, "Group call notification is gone.\n");
 		/* Change to NULL state. */
@@ -1165,12 +1167,12 @@ static void vgcs_gcc_fsm_u3_action(struct osmo_fsm_inst *fi, uint32_t event, voi
 		/* Free transaction. */
 		trans_free(trans);
 		break;
-	case VGCS_GCC_EV_ABORT_IND:
+	case VGCS_GCC_EV_REL_IND:
 		/* The notified call is gone. */
 		LOG_GCC(trans, LOGL_INFO, "Received call from network is gone.\n");
 		/* Change to NULL state. */
 		osmo_fsm_inst_state_chg(fi, VGCS_GCC_ST_U0_NULL, 0, 0);
-		/* Notify termination at VTY. (No cause, because notification is gone.) */
+		/* Notify termination at VTY. */
 		vgcs_vty_notify(trans, "Released\n");
 		/* Free transaction. */
 		trans_free(trans);
@@ -1193,6 +1195,7 @@ static void vgcs_gcc_fsm_u4_onenter(struct osmo_fsm_inst *fi, uint32_t prev_stat
 static void vgcs_gcc_fsm_u4_action(struct osmo_fsm_inst *fi, uint32_t event, void *data)
 {
 	struct gsm_trans *trans = fi->priv;
+	uint8_t *cause = data;
 
 	switch (event) {
 	case VGCS_GCC_EV_JOIN_GC_CNF:
@@ -1209,16 +1212,24 @@ static void vgcs_gcc_fsm_u4_action(struct osmo_fsm_inst *fi, uint32_t event, voi
 		/* Free transaction. */
 		trans_free(trans);
 		break;
-	case VGCS_GCC_EV_ABORT_IND:
+	case VGCS_GCC_EV_REL_IND:
 		/* The notified call is gone. */
 		LOG_GCC(trans, LOGL_INFO, "Received call from network is gone.\n");
 		/* Change to NULL state. */
 		osmo_fsm_inst_state_chg(fi, VGCS_GCC_ST_U0_NULL, 0, 0);
-		/* Notify termination at VTY. (No cause, because notification is gone.) */
+		/* Notify termination at VTY. */
 		vgcs_vty_notify(trans, "Released\n");
 		/* Free transaction. */
 		trans_free(trans);
 		break;
+	case VGCS_GCC_EV_ABORT_IND:
+		/* The notified call is gone. */
+		LOG_GCC(trans, LOGL_INFO, "Call rejected.\n");
+		/* Change back to U3 state, so that call may be joined later. */
+		osmo_fsm_inst_state_chg(fi, VGCS_GCC_ST_U3_GROUP_CALL_PRESENT, 0, 0);
+		/* Notify termination at VTY. */
+		vgcs_vty_notify(trans, "Released (cause %d)\n", *cause);
+		break;
 	case VGCS_GCC_EV_TIMEOUT:
 		/* Group channel timed out. */
 		LOG_GCC(trans, LOGL_INFO, "Timeout waiting for group channel.\n");
@@ -1417,7 +1428,7 @@ static const struct osmo_fsm_state vgcs_gcc_fsm_states[] = {
 		.in_event_mask = S(VGCS_GCC_EV_SETUP_IND) |
 				 S(VGCS_GCC_EV_TERM_REQ) |
 				 S(VGCS_GCC_EV_ABORT_REQ) |
-				 S(VGCS_GCC_EV_ABORT_IND) |
+				 S(VGCS_GCC_EV_REL_IND) |
 				 S(VGCS_GCC_EV_TIMEOUT),
 		.out_state_mask = S(VGCS_GCC_ST_U2r_U6_GROUP_CALL_ACTIVE) |
 				  S(VGCS_GCC_ST_U4_GROUP_CALL_CONN_REQUEST) |
@@ -1430,7 +1441,7 @@ static const struct osmo_fsm_state vgcs_gcc_fsm_states[] = {
 		.name = "GROUP CALL PRESENT (U3)",
 		.in_event_mask = S(VGCS_GCC_EV_JOIN_GC_REQ) |
 				 S(VGCS_GCC_EV_ABORT_REQ) |
-				 S(VGCS_GCC_EV_ABORT_IND),
+				 S(VGCS_GCC_EV_REL_IND),
 		.out_state_mask = S(VGCS_GCC_ST_U0_NULL) |
 				  S(VGCS_GCC_ST_U4_GROUP_CALL_CONN_REQUEST) |
 				  S(VGCS_GCC_ST_U2nc_GROUP_CALL_ACTIVE),
@@ -1441,9 +1452,11 @@ static const struct osmo_fsm_state vgcs_gcc_fsm_states[] = {
 		.name = "GROUP CALL CONNECTION REQUEST (U4)",
 		.in_event_mask = S(VGCS_GCC_EV_JOIN_GC_CNF) |
 				 S(VGCS_GCC_EV_ABORT_REQ) |
+				 S(VGCS_GCC_EV_REL_IND) |
 				 S(VGCS_GCC_EV_ABORT_IND) |
 				 S(VGCS_GCC_EV_TIMEOUT),
 		.out_state_mask = S(VGCS_GCC_ST_U2r_U6_GROUP_CALL_ACTIVE) |
+				  S(VGCS_GCC_ST_U3_GROUP_CALL_PRESENT) |
 				  S(VGCS_GCC_ST_U0_NULL),
 		.onenter = vgcs_gcc_fsm_u4_onenter,
 		.action = vgcs_gcc_fsm_u4_action,
@@ -1610,7 +1623,6 @@ int gsm44068_rcv_gcc_bcc(struct osmocom_ms *ms, struct msgb *msg)
 	uint8_t pdisc;
 	struct gsm_trans *trans;
 	int rc = 0;
-	uint8_t cause;
 
 	/* Check for message class and get protocol type. */
 	switch ((msg_type & GSM48_MMXX_MASK)) {
@@ -1684,6 +1696,9 @@ int gsm44068_rcv_gcc_bcc(struct osmocom_ms *ms, struct msgb *msg)
 	case GSM48_MMBCC_ERR_IND:
 	case GSM48_MMGCC_REL_IND:
 	case GSM48_MMBCC_REL_IND:
+		/* Ignore release confirm or release collision. */
+		if (trans->gcc.fi->state == VGCS_GCC_ST_U3_GROUP_CALL_PRESENT)
+			break;
 		/* If MM fails or is rejected during U0.p state, this is a MM-EST-REJ. */
 		if (trans->gcc.fi->state == VGCS_GCC_ST_U0p_MM_CONNECTION_PENDING)
 			osmo_fsm_inst_dispatch(trans->gcc.fi, VGCS_GCC_EV_MM_EST_REJ, &mmh->cause);
@@ -1713,9 +1728,8 @@ int gsm44068_rcv_gcc_bcc(struct osmocom_ms *ms, struct msgb *msg)
 			if (trans->gcc.fi->state == VGCS_GCC_ST_U3_GROUP_CALL_PRESENT ||
 			    trans->gcc.fi->state == VGCS_GCC_ST_U4_GROUP_CALL_CONN_REQUEST ||
 			    trans->gcc.fi->state == VGCS_GCC_ST_U2nc_GROUP_CALL_ACTIVE) {
-				/* If notification is gone, abort pending received call. */
-				cause = GSM48_CC_CAUSE_NORM_CALL_CLEAR;
-				osmo_fsm_inst_dispatch(trans->gcc.fi, VGCS_GCC_EV_ABORT_IND, &cause);
+				/* If notification is gone, release pending received call. */
+				osmo_fsm_inst_dispatch(trans->gcc.fi, VGCS_GCC_EV_REL_IND, NULL);
 			}
 			break;
 		}