fraud_detection: Fix the 'call duration' events

The 'call duration' events were not being raised anymore since commit
a0fcf85, due to the mismatching callback type check in
dialog_terminate_CB().

Also rework commit a0fcf85, where instead of switching the
decrement operation on the DLGCB_DESTROY callback (to guarantee it only
gets called one time), we just store and use a boolean marker, thus
achieving the same effect but while using the optimal callbacks!

modules/fraud_detection/fraud_detection.c

@@ -434,7 +434,7 @@ static int check_fraud(struct sip_msg *msg, str *user, str *number, int *pid)
 		param->calldur_crit = thr->call_duration_thr.critical;
 		param->interval_id = se->interval_id;
 
-		if (dlgb.register_dlgcb(dlgc, DLGCB_DESTROY,
+		if (dlgb.register_dlgcb(dlgc, DLGCB_FAILED|DLGCB_TERMINATED|DLGCB_EXPIRED,
 					dialog_terminate_CB, param, free_dialog_CB_param) != 0) {
 			LM_ERR("failed to register dialog terminated callback\n");
 			shm_free(param->number.s);

modules/fraud_detection/frd_events.c

@@ -151,18 +151,24 @@ void dialog_terminate_CB(struct dlg_cell *dlg, int type,
 	extern str call_dur_name;
 	frd_dlg_param *frdparam = (frd_dlg_param*) *(params->param);
 
-	if (type & (DLGCB_TERMINATED|DLGCB_EXPIRED)) {
-		unsigned int duration = time(NULL) - dlg->start_ts;
-		if (frdparam->calldur_crit && duration >= frdparam->calldur_crit)
-			raise_critical_event(&call_dur_name, &duration,
-					&frdparam->calldur_crit,
-					&frdparam->user, &frdparam->number, &frdparam->ruleid);
-
-		else if (frdparam->calldur_warn && duration >= frdparam->calldur_warn)
-			raise_warning_event(&call_dur_name, &duration,
-					&frdparam->calldur_warn,
-					&frdparam->user, &frdparam->number, &frdparam->ruleid);
-	}
+	if (frdparam->dlg_terminated ||
+	        !(type & (DLGCB_FAILED|DLGCB_TERMINATED|DLGCB_EXPIRED)))
+		return;
+	frdparam->dlg_terminated = 1;
+
+	unsigned int duration = time(NULL) - dlg->start_ts;
+	LM_DBG("call-duration: %u sec (warn: %u, crit: %u), dlgcb: %d\n",
+	       duration, frdparam->calldur_warn, frdparam->calldur_crit, type);
+
+	if (frdparam->calldur_crit && duration >= frdparam->calldur_crit)
+		raise_critical_event(&call_dur_name, &duration,
+				&frdparam->calldur_crit,
+				&frdparam->user, &frdparam->number, &frdparam->ruleid);
+
+	else if (frdparam->calldur_warn && duration >= frdparam->calldur_warn)
+		raise_warning_event(&call_dur_name, &duration,
+				&frdparam->calldur_warn,
+				&frdparam->user, &frdparam->number, &frdparam->ruleid);
 
 	lock_get(&frdparam->stats->lock);
 	if (frdparam->interval_id == frdparam->stats->interval_id)

modules/fraud_detection/frd_events.h

@@ -48,6 +48,8 @@ typedef struct {
 
 	unsigned int calldur_warn;
 	unsigned int calldur_crit;
+
+	int dlg_terminated;
 } frd_dlg_param;
 
  void dialog_terminate_CB(struct dlg_cell *dlgc, int type,