[NETD-BPF#1] Move libnetdutils to frameworks/libs/net/...

libnetdutils is referenced by netd.c and TrafficController.cpp, which
are going to be mainlined. Therefore, move libnetdutils to a common
place where both mainline module and platform code (Netd) can refer to.

Bug: 202086915
Test: build; flash; cd system/netd; atest
Ignore-AOSP-First: the netd change(same topic) would not automerge from
aosp.
No-Typo-Check: Clean code move with no other changes.
BYPASS_INCLUSIVE_LANGUAGE_REASON=Clean code move with no other changes.
Change-Id: I645bfe35f6543149c9a9f894cd4158d27a481abe

staticlibs/netd/libnetdutils/Status.cpp

@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2017 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.
+ */
+
+#include "netdutils/Status.h"
+
+#include <sstream>
+
+#include "android-base/stringprintf.h"
+
+namespace android {
+namespace netdutils {
+
+Status statusFromErrno(int err, const std::string& msg) {
+    return Status(err, base::StringPrintf("[%s] : %s", strerror(err), msg.c_str()));
+}
+
+bool equalToErrno(const Status& status, int err) {
+    return status.code() == err;
+}
+
+std::string toString(const Status& status) {
+    std::stringstream ss;
+    ss << status;
+    return ss.str();
+}
+
+std::ostream& operator<<(std::ostream& os, const Status& s) {
+    return os << "Status[code: " << s.code() << ", msg: \"" << s.msg() << "\"]";
+}
+
+}  // namespace netdutils
+}  // namespace android