Implement a global switch on the network to disable call waiting.

Add a network -> callwaiting VTY command as boolean.

When this is enabled (default) there is no change to
operation previous to this commit.

When this switch is disabled with "no call-waiting" in vty
then when a call arrives, we will check if we have an active
call transaction for this subscriber, no matter if it is
establishing, established, or alerting, in any of these cases we
will return USER BUSY to the calling party.

Change-Id: I3eb6f23f7103e3002874fb5d3a30c9de952202ae

2 files changed, 47 insertions, 3 deletions

diff --git a/src/libmsc/gsm_04_08_cc.c b/src/libmsc/gsm_04_08_cc.c
index e83caa22f..ed74e88bb 100644
--- a/src/libmsc/gsm_04_08_cc.c
+++ b/src/libmsc/gsm_04_08_cc.c
@@ -1909,6 +1909,25 @@ static int mncc_tx_to_gsm_cc(struct gsm_network *net, const union mncc_msg *msg)
 						GSM48_CAUSE_LOC_PRN_S_LU,
 						GSM48_CC_CAUSE_DEST_OOO);
 		}
+
+		/* Find valid conn */
+		msc_a = msc_a_for_vsub(vsub, true);
+
+		/* If subscriber is BUSY and we do not DO call in call aka "call-waiting" */
+		if (!net->call_waiting && msc_a) {
+			struct gsm_trans *existing_cc_trans = trans_find_by_type(msc_a, TRANS_CC);
+			if (existing_cc_trans && existing_cc_trans->cc.state != GSM_CSTATE_NULL) {
+				LOG_TRANS_CAT(existing_cc_trans, DCC, LOGL_NOTICE,
+					      "rx '%s' for subscriber %s with trans state (%s)"
+					      " rejecting with USER_BUSY\n",
+					get_mncc_name(msg->msg_type), data->called.number,
+					gsm48_cc_state_name(existing_cc_trans->cc.state));
+				return mncc_release_ind(net, NULL, data->callref,
+							GSM48_CAUSE_LOC_PRN_S_LU,
+							GSM48_CC_CAUSE_USER_BUSY);
+			}
+		}
+
 		/* Create transaction */
 		trans = trans_alloc(net, vsub, TRANS_CC,
 				    TRANS_ID_UNASSIGNED, data->callref);
@@ -1922,9 +1941,6 @@ static int mncc_tx_to_gsm_cc(struct gsm_network *net, const union mncc_msg *msg)
 			return -ENOMEM;
 		}
 
-		/* Find valid conn */
-		msc_a = msc_a_for_vsub(vsub, true);
-
 		/* If subscriber has no conn */
 		if (!msc_a) {
 
diff --git a/src/libmsc/msc_vty.c b/src/libmsc/msc_vty.c
index 4674e2e68..09aef9168 100644
--- a/src/libmsc/msc_vty.c
+++ b/src/libmsc/msc_vty.c
@@ -330,6 +330,29 @@ DEFUN(cfg_net_no_per_loc_upd, cfg_net_no_per_loc_upd_cmd,
 	return CMD_SUCCESS;
 }
 
+DEFUN(cfg_net_call_wait, cfg_net_call_wait_cmd,
+      "call-waiting",
+      "Enable Call Waiting on the Network\n")
+{
+	struct gsm_network *net = vty->index;
+
+	net->call_waiting = true;
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_net_no_call_wait, cfg_net_no_call_wait_cmd,
+      "no call-waiting",
+      NO_STR
+      "Disable Call Waiting on the Network\n")
+{
+	struct gsm_network *net = vty->index;
+
+	net->call_waiting = false;
+
+	return CMD_SUCCESS;
+}
+
 static int config_write_net(struct vty *vty)
 {
 	int i;
@@ -376,6 +399,9 @@ static int config_write_net(struct vty *vty)
 			gsmnet->emergency.route_to_msisdn, VTY_NEWLINE);
 	}
 
+	if (!gsmnet->call_waiting)
+		vty_out(vty, " no call-waiting%s", VTY_NEWLINE);
+
 	return CMD_SUCCESS;
 }
 
@@ -1946,6 +1972,8 @@ void msc_vty_init(struct gsm_network *msc_network)
 	install_element(GSMNET_NODE, &cfg_net_no_timezone_cmd);
 	install_element(GSMNET_NODE, &cfg_net_per_loc_upd_cmd);
 	install_element(GSMNET_NODE, &cfg_net_no_per_loc_upd_cmd);
+	install_element(GSMNET_NODE, &cfg_net_call_wait_cmd);
+	install_element(GSMNET_NODE, &cfg_net_no_call_wait_cmd);
 
 	install_element(CONFIG_NODE, &cfg_msc_cmd);
 	install_node(&msc_node, config_write_msc);