WPS: Separate local error from max queue length reached

Drop subscription only if the max queue length has been reached;
not based on any error.

src/wps/wps_upnp.c

@@ -499,7 +499,7 @@ static void upnp_wps_device_send_event(struct upnp_wps_device_sm *sm)
 
 	dl_list_for_each_safe(s, tmp, &sm->subscriptions, struct subscription,
 			      list) {
-		if (event_add(s, buf)) {
+		if (event_add(s, buf) == 1) {
 			wpa_printf(MSG_INFO, "WPS UPnP: Dropping "
 				   "subscriber %p due to event backlog", s);
 			dl_list_del(&s->list);
@@ -608,6 +608,7 @@ static int subscription_first_event(struct subscription *s)
 		"<e:propertyset xmlns:e=\"urn:schemas-upnp-org:event-1-0\">\n";
 	const char *tail = "</e:propertyset>\n";
 	char txt[10];
+	int ret;
 
 	if (s->sm->wlanevent == NULL) {
 		/*
@@ -639,7 +640,7 @@ static int subscription_first_event(struct subscription *s)
 	}
 	buf = wpabuf_alloc(500 + os_strlen(wlan_event));
 	if (buf == NULL)
-		return 1;
+		return -1;
 
 	wpabuf_put_str(buf, head);
 	wpabuf_put_property(buf, "STAStatus", "1");
@@ -649,9 +650,10 @@ static int subscription_first_event(struct subscription *s)
 		wpabuf_put_property(buf, "WLANEvent", wlan_event);
 	wpabuf_put_str(buf, tail);
 
-	if (event_add(s, buf)) {
+	ret = event_add(s, buf);
+	if (ret) {
 		wpabuf_free(buf);
-		return 1;
+		return ret;
 	}
 	wpabuf_free(buf);
 

src/wps/wps_upnp_event.c

@@ -365,7 +365,7 @@ void event_send_stop_all(struct upnp_wps_device_sm *sm)
  * event_add - Add a new event to a queue
  * @s: Subscription
  * @data: Event data (is copied; caller retains ownership)
- * Returns: 0 on success, 1 on error
+ * Returns: 0 on success, -1 on error, 1 on max event queue limit reached
  */
 int event_add(struct subscription *s, const struct wpabuf *data)
 {
@@ -381,13 +381,13 @@ int event_add(struct subscription *s, const struct wpabuf *data)
 
 	e = os_zalloc(sizeof(*e));
 	if (e == NULL)
-		return 1;
+		return -1;
 	dl_list_init(&e->list);
 	e->s = s;
 	e->data = wpabuf_dup(data);
 	if (e->data == NULL) {
 		os_free(e);
-		return 1;
+		return -1;
 	}
 	e->subscriber_sequence = s->next_subscriber_sequence++;
 	if (s->next_subscriber_sequence == 0)