P2P: Remove P2P group on driver resource becoming unavailable

Add a new driver event, EVENT_INTERFACE_UNAVAILABLE, for indicating
that the driver is not able to continue operating the virtual
interface in its current mode anymore, e.g., due to operating
channel for GO interface forced to a DFS channel by another virtual
interface.

When this happens for a P2P group interface, the P2P group will
be terminated and P2P-GROUP-REMOVED event shows the reason for
this as follows:
P2P-GROUP-REMOVED wlan0 GO reason=UNAVAILABLE

src/drivers/driver.h

@@ -2212,7 +2212,21 @@ enum wpa_event_type {
 	 * e.g., because of a regulatory domain change triggered by scan
 	 * results including an AP advertising a country code.
 	 */
-	EVENT_CHANNEL_LIST_CHANGED
+	EVENT_CHANNEL_LIST_CHANGED,
+
+	/**
+	 * EVENT_INTERFACE_UNAVAILABLE - Notify that interface is unavailable
+	 *
+	 * This event is used to indicate that the driver cannot maintain this
+	 * interface in its operation mode anymore. The most likely use for
+	 * this is to indicate that AP mode operation is not available due to
+	 * operating channel would need to be changed to a DFS channel when
+	 * the driver does not support radar detection and another virtual
+	 * interfaces caused the operating channel to change. Other similar
+	 * resource conflicts could also trigger this for station mode
+	 * interfaces.
+	 */
+	EVENT_INTERFACE_UNAVAILABLE
 };
 
 

wpa_supplicant/events.c

@@ -1837,6 +1837,11 @@ void wpa_supplicant_event(void *ctx, enum wpa_event_type event,
 			break; /* Ignore event during drv initialization */
 #ifdef CONFIG_P2P
 		wpas_p2p_update_channel_list(wpa_s);
+#endif /* CONFIG_P2P */
+		break;
+	case EVENT_INTERFACE_UNAVAILABLE:
+#ifdef CONFIG_P2P
+		wpas_p2p_interface_unavailable(wpa_s);
 #endif /* CONFIG_P2P */
 		break;
 	default:

wpa_supplicant/p2p_supplicant.c

@@ -220,6 +220,9 @@ static void wpas_p2p_group_delete(struct wpa_supplicant *wpa_s)
 	case P2P_GROUP_REMOVAL_IDLE_TIMEOUT:
 		reason = " reason=IDLE";
 		break;
+	case P2P_GROUP_REMOVAL_UNAVAILABLE:
+		reason = " reason=UNAVAILABLE";
+		break;
 	default:
 		reason = "";
 		break;
@@ -3742,3 +3745,15 @@ int wpas_p2p_cancel(struct wpa_supplicant *wpa_s)
 
 	return 0;
 }
+
+
+void wpas_p2p_interface_unavailable(struct wpa_supplicant *wpa_s)
+{
+	if (wpa_s->current_ssid == NULL || !wpa_s->current_ssid->p2p_group)
+		return;
+
+	wpa_printf(MSG_DEBUG, "P2P: Remove group due to driver resource not "
+		   "being available anymore");
+	wpa_s->removal_reason = P2P_GROUP_REMOVAL_UNAVAILABLE;
+	wpas_p2p_group_delete(wpa_s);
+}

wpa_supplicant/p2p_supplicant.h

@@ -117,5 +117,6 @@ void wpas_p2p_notif_disconnected(struct wpa_supplicant *wpa_s);
 int wpas_p2p_notif_pbc_overlap(struct wpa_supplicant *wpa_s);
 void wpas_p2p_update_channel_list(struct wpa_supplicant *wpa_s);
 int wpas_p2p_cancel(struct wpa_supplicant *wpa_s);
+void wpas_p2p_interface_unavailable(struct wpa_supplicant *wpa_s);
 
 #endif /* P2P_SUPPLICANT_H */

wpa_supplicant/wpa_supplicant_i.h

@@ -518,7 +518,8 @@ struct wpa_supplicant {
 	enum {
 		P2P_GROUP_REMOVAL_UNKNOWN,
 		P2P_GROUP_REMOVAL_REQUESTED,
-		P2P_GROUP_REMOVAL_IDLE_TIMEOUT
+		P2P_GROUP_REMOVAL_IDLE_TIMEOUT,
+		P2P_GROUP_REMOVAL_UNAVAILABLE
 	} removal_reason;
 #endif /* CONFIG_P2P */