fix nrf52 mtu

Author: paul-szczepanek-arm

features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NORDIC_SOFTDEVICE/TARGET_NRF52/source/btle/btle.cpp

@@ -400,10 +400,12 @@ void btle_handler(const ble_evt_t *p_ble_evt)
                     p_ble_evt->evt.gatts_evt.params.exchange_mtu_request;
 
                 nRF5xGattServer &gatt_server = (nRF5xGattServer&) ble.getGattServer();
-                gatt_server.getEventHandler()->onAttMtuChange(
-                    connection,
-                    std::min(NRF_SDH_BLE_GATT_MAX_MTU_SIZE, (int)(update.client_rx_mtu))
-                );
+                if (gatt_server.getEventHandler()) {
+                    gatt_server.getEventHandler()->onAttMtuChange(
+                        connection,
+                        std::min(NRF_SDH_BLE_GATT_MAX_MTU_SIZE, (int)(update.client_rx_mtu))
+                    );
+                }
             }
             break;
         }
@@ -415,11 +417,13 @@ void btle_handler(const ble_evt_t *p_ble_evt)
                 const ble_gattc_evt_exchange_mtu_rsp_t &update =
                     p_ble_evt->evt.gattc_evt.params.exchange_mtu_rsp;
 
-                nRF5xGattServer &gatt_client = (nRF5xGattClient&) ble.getGattClient();
-                gatt_client.getEventHandler()->onAttMtuChange(
-                    connection,
-                    std::min(NRF_SDH_BLE_GATT_MAX_MTU_SIZE, (int)(update.server_rx_mtu))
-                );
+                nRF5xGattClient &gatt_client = (nRF5xGattClient&) ble.getGattClient();
+                if (gatt_client.get_event_handler()) {
+                    gatt_client.get_event_handler()->on_att_mtu_change(
+                        connection,
+                        std::min(NRF_SDH_BLE_GATT_MAX_MTU_SIZE, (int)(update.server_rx_mtu))
+                    );
+                }
             }
             break;
         }