Add a wifi hal interface to read-back the APF memory.

Test: builds, boots on marlin.
Change-Id: I860ee093b585bedd800830ea05516ad054a8dc3a

wifi/1.2/Android.bp

@@ -13,6 +13,7 @@ hidl_interface {
         "IWifiChipEventCallback.hal",
         "IWifiNanIface.hal",
         "IWifiNanIfaceEventCallback.hal",
+        "IWifiStaIface.hal",
     ],
     interfaces: [
         "android.hardware.wifi@1.0",

wifi/1.2/IWifiStaIface.hal

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.hardware.wifi@1.2;
+
+import @1.0::WifiStatus;
+import @1.0::IWifiStaIface;
+
+/**
+ * Interface used to represent a single STA iface.
+ *
+ * IWifiChip.createStaIface() may return a @1.2::IWifiStaIface when supported.
+ */
+interface IWifiStaIface extends @1.0::IWifiStaIface {
+    /**
+     * Fetches a consistent snapshot of the entire APF program and working
+     * memory buffer and returns it to the host. The returned buffer contains
+     * both code and data. Its length must match the most recently returned
+     * |StaApfPacketFilterCapabilities.maxLength|.
+     *
+     * While the snapshot is being fetched, the APF intepreter must not execute
+     * and all incoming packets must be passed to the host as if there was no
+     * APF program installed.
+     *
+     * Must fail with |WifiStatusCode.ERROR_NOT_SUPPORTED| if
+     * |StaIfaceCapabilityMask.APF| is not set.
+     *
+     * @return status WifiStatus of the operation.
+     *         Possible status codes:
+     *         |WifiStatusCode.SUCCESS|,
+     *         |WifiStatusCode.ERROR_WIFI_IFACE_INVALID|,
+     *         |WifiStatusCode.ERROR_NOT_SUPPORTED|,
+     *         |WifiStatusCode.ERROR_NOT_AVAILABLE|,
+     *         |WifiStatusCode.ERROR_UNKNOWN|
+     * @return data The entire APF working memory buffer when status is
+     *         |WifiStatusCode.SUCCESS|, empty otherwise.
+     * @see getApfPacketFilterCapabilities()
+     * @see installApfPacketFilter()
+     */
+    readApfPacketFilterData() generates (WifiStatus status, vec<uint8_t> data);
+};