Migrate netlink-client to net-utils-device-common-netlink.

Move netlink stuff to frameworks/libs/net/common/device, and build the
source files as an individual libraray. NetworkStack module just depends
on the net-utils-device-common-netlink.

Besides, also fix the incorrect format detected by checkstyle_hook script
such as missing java doc and make some public function as private, rename
the variable and etc.

Bug: 192535368
Test: atest NetworkStaticlibTests
Change-Id: I00e7f30be1bc9ebc2e24d7cd53efc403d6ba3daa

1 files changed, 77 insertions, 0 deletions

diff --git a/common/device/com/android/net/module/util/netlink/StructNlMsgErr.java b/common/device/com/android/net/module/util/netlink/StructNlMsgErr.java
new file mode 100644
index 00000000..b6620f3b
--- /dev/null
+++ b/common/device/com/android/net/module/util/netlink/StructNlMsgErr.java
@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2019 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 com.android.net.module.util.netlink;
+
+import java.nio.ByteBuffer;
+
+/**
+ * struct nlmsgerr
+ *
+ * see <linux_src>/include/uapi/linux/netlink.h
+ *
+ * @hide
+ */
+public class StructNlMsgErr {
+    public static final int STRUCT_SIZE = Integer.BYTES + StructNlMsgHdr.STRUCT_SIZE;
+
+    private static boolean hasAvailableSpace(ByteBuffer byteBuffer) {
+        return byteBuffer != null && byteBuffer.remaining() >= STRUCT_SIZE;
+    }
+
+    /**
+     * Parse a netlink error message payload from a {@link ByteBuffer}.
+     *
+     * @param byteBuffer The buffer from which to parse the netlink error message payload.
+     * @return the parsed netlink error message payload, or {@code null} if the netlink error
+     *         message payload could not be parsed successfully (for example, if it was truncated).
+     */
+    public static StructNlMsgErr parse(ByteBuffer byteBuffer) {
+        if (!hasAvailableSpace(byteBuffer)) return null;
+
+        // The ByteOrder must have already been set by the caller.  In most
+        // cases ByteOrder.nativeOrder() is correct, with the exception
+        // of usage within unittests.
+        final StructNlMsgErr struct = new StructNlMsgErr();
+        struct.error = byteBuffer.getInt();
+        struct.msg = StructNlMsgHdr.parse(byteBuffer);
+        return struct;
+    }
+
+    public int error;
+    public StructNlMsgHdr msg;
+
+    /**
+     * Write the netlink error message payload to {@link ByteBuffer}.
+     */
+    public void pack(ByteBuffer byteBuffer) {
+        // The ByteOrder must have already been set by the caller.  In most
+        // cases ByteOrder.nativeOrder() is correct, with the possible
+        // exception of usage within unittests.
+        byteBuffer.putInt(error);
+        if (msg != null) {
+            msg.pack(byteBuffer);
+        }
+    }
+
+    @Override
+    public String toString() {
+        return "StructNlMsgErr{ "
+                + "error{" + error + "}, "
+                + "msg{" + (msg == null ? "" : msg.toString()) + "} "
+                + "}";
+    }
+}