[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/MemBlockTest.cpp

@@ -0,0 +1,146 @@
+/*
+ * Copyright (C) 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.
+ */
+
+#include <algorithm>
+#include <cstdint>
+#include <utility>
+
+#include <gtest/gtest.h>
+
+#include "netdutils/MemBlock.h"
+#include "netdutils/Slice.h"
+
+namespace android {
+namespace netdutils {
+
+namespace {
+
+constexpr unsigned DNS_PACKET_SIZE = 512;
+constexpr int ARBITRARY_VALUE = 0x55;
+
+MemBlock makeArbitraryMemBlock(size_t len) {
+    MemBlock result(len);
+    // Do some fictional work before returning.
+    for (Slice slice = result.get(); !slice.empty(); slice = drop(slice, 1)) {
+        slice.base()[0] = ARBITRARY_VALUE;
+    }
+    return result;
+}
+
+void checkAllZeros(Slice slice) {
+    for (; !slice.empty(); slice = drop(slice, 1)) {
+        EXPECT_EQ(0U, slice.base()[0]);
+    }
+}
+
+void checkArbitraryMemBlock(const MemBlock& block, size_t expectedSize) {
+    Slice slice = block.get();
+    EXPECT_EQ(expectedSize, slice.size());
+    EXPECT_NE(nullptr, slice.base());
+    for (; !slice.empty(); slice = drop(slice, 1)) {
+        EXPECT_EQ(ARBITRARY_VALUE, slice.base()[0]);
+    }
+}
+
+void checkHelloMello(Slice dest, Slice src) {
+    EXPECT_EQ('h', dest.base()[0]);
+    EXPECT_EQ('e', dest.base()[1]);
+    EXPECT_EQ('l', dest.base()[2]);
+    EXPECT_EQ('l', dest.base()[3]);
+    EXPECT_EQ('o', dest.base()[4]);
+
+    src.base()[0] = 'm';
+    EXPECT_EQ('h', dest.base()[0]);
+}
+
+}  // namespace
+
+TEST(MemBlockTest, Empty) {
+    MemBlock empty;
+    EXPECT_TRUE(empty.get().empty());
+    EXPECT_EQ(nullptr, empty.get().base());
+}
+
+TEST(MemBlockTest, ExplicitZero) {
+    MemBlock zero(0);
+    EXPECT_TRUE(zero.get().empty());
+    EXPECT_EQ(nullptr, zero.get().base());
+}
+
+TEST(MemBlockTest, BasicAllocation) {
+    MemBlock dnsPacket(DNS_PACKET_SIZE);
+    Slice slice = dnsPacket.get();
+    EXPECT_EQ(DNS_PACKET_SIZE, slice.size());
+    // Verify the space is '\0'-initialized.
+    ASSERT_NO_FATAL_FAILURE(checkAllZeros(slice));
+    EXPECT_NE(nullptr, slice.base());
+}
+
+TEST(MemBlockTest, MoveConstruction) {
+    MemBlock block(makeArbitraryMemBlock(DNS_PACKET_SIZE));
+    ASSERT_NO_FATAL_FAILURE(checkArbitraryMemBlock(block, DNS_PACKET_SIZE));
+}
+
+TEST(MemBlockTest, MoveAssignmentOrConstruction) {
+    MemBlock block = makeArbitraryMemBlock(DNS_PACKET_SIZE);
+    ASSERT_NO_FATAL_FAILURE(checkArbitraryMemBlock(block, DNS_PACKET_SIZE));
+}
+
+TEST(MemBlockTest, StdMoveAssignment) {
+    constexpr unsigned SIZE = 10;
+
+    MemBlock block;
+    EXPECT_TRUE(block.get().empty());
+    EXPECT_EQ(nullptr, block.get().base());
+
+    {
+        MemBlock block2 = makeArbitraryMemBlock(SIZE);
+        EXPECT_EQ(SIZE, block2.get().size());
+        // More fictional work.
+        for (unsigned i = 0; i < SIZE; i++) {
+            block2.get().base()[i] = i;
+        }
+        block = std::move(block2);
+    }
+
+    EXPECT_EQ(SIZE, block.get().size());
+    for (unsigned i = 0; i < SIZE; i++) {
+        EXPECT_EQ(i, block.get().base()[i]);
+    }
+}
+
+TEST(MemBlockTest, ConstructionFromSlice) {
+    uint8_t data[] = {'h', 'e', 'l', 'l', 'o'};
+    Slice dataSlice(Slice(data, sizeof(data) / sizeof(data[0])));
+
+    MemBlock dataCopy(dataSlice);
+    ASSERT_NO_FATAL_FAILURE(checkHelloMello(dataCopy.get(), dataSlice));
+}
+
+TEST(MemBlockTest, ImplicitCastToSlice) {
+    uint8_t data[] = {'h', 'e', 'l', 'l', 'o'};
+    Slice dataSlice(Slice(data, sizeof(data) / sizeof(data[0])));
+
+    MemBlock dataCopy(dataSlice.size());
+    // NOTE: no explicit MemBlock::get().
+    // Verify the space is '\0'-initialized.
+    ASSERT_NO_FATAL_FAILURE(checkAllZeros(dataCopy));
+    copy(dataCopy, dataSlice);
+    ASSERT_NO_FATAL_FAILURE(checkHelloMello(dataCopy, dataSlice));
+}
+
+}  // namespace netdutils
+}  // namespace android