[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
2021-10-21 22:18:59 +08:00
parent d7767f182e
commit d27d6c9062
48 changed files with 5253 additions and 0 deletions
--- a/staticlibs/netd/libnetdutils/Android.bp
+++ b/staticlibs/netd/libnetdutils/Android.bp
@@ -0,0 +1,65 @@
+package {
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+cc_library {
+    name: "libnetdutils",
+    srcs: [
+        "DumpWriter.cpp",
+        "Fd.cpp",
+        "InternetAddresses.cpp",
+        "Log.cpp",
+        "Netfilter.cpp",
+        "Netlink.cpp",
+        "Slice.cpp",
+        "Socket.cpp",
+        "SocketOption.cpp",
+        "Status.cpp",
+        "Syscalls.cpp",
+        "UniqueFd.cpp",
+        "UniqueFile.cpp",
+    ],
+    defaults: ["netd_defaults"],
+    cflags: ["-Wall", "-Werror"],
+    shared_libs: [
+        "libbase",
+        "liblog",
+    ],
+    export_shared_lib_headers: [
+        "libbase",
+    ],
+    export_include_dirs: ["include"],
+    sanitize: {
+        cfi: true,
+    },
+
+    apex_available: [
+        "//apex_available:platform",
+        "com.android.resolv",
+    ],
+    min_sdk_version: "29",
+}
+
+cc_test {
+    name: "netdutils_test",
+    srcs: [
+        "BackoffSequenceTest.cpp",
+        "FdTest.cpp",
+        "InternetAddressesTest.cpp",
+        "LogTest.cpp",
+        "MemBlockTest.cpp",
+        "SliceTest.cpp",
+        "StatusTest.cpp",
+        "SyscallsTest.cpp",
+        "ThreadUtilTest.cpp",
+    ],
+    defaults: ["netd_defaults"],
+    test_suites: ["device-tests"],
+    static_libs: [
+        "libgmock",
+        "libnetdutils",
+    ],
+    shared_libs: [
+        "libbase",
+    ],
+}
--- a/staticlibs/netd/libnetdutils/BackoffSequenceTest.cpp
+++ b/staticlibs/netd/libnetdutils/BackoffSequenceTest.cpp
@@ -0,0 +1,186 @@
+/*
+ * 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 <gtest/gtest.h>
+
+#include "netdutils/BackoffSequence.h"
+
+namespace android {
+namespace netdutils {
+
+TEST(BackoffSequence, defaults) {
+    BackoffSequence<uint32_t> backoff;
+
+    EXPECT_TRUE(backoff.hasNextTimeout());
+    EXPECT_EQ(0x00000001U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000002U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000004U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000008U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000010U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000020U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000040U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000080U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000100U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000200U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000400U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000800U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00001000U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00002000U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00004000U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00008000U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00010000U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00020000U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00040000U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00080000U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00100000U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00200000U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00400000U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00800000U, backoff.getNextTimeout());
+    EXPECT_EQ(0x01000000U, backoff.getNextTimeout());
+    EXPECT_EQ(0x02000000U, backoff.getNextTimeout());
+    EXPECT_EQ(0x04000000U, backoff.getNextTimeout());
+    EXPECT_EQ(0x08000000U, backoff.getNextTimeout());
+    EXPECT_EQ(0x10000000U, backoff.getNextTimeout());
+    EXPECT_EQ(0x20000000U, backoff.getNextTimeout());
+    EXPECT_EQ(0x40000000U, backoff.getNextTimeout());
+    EXPECT_EQ(0x80000000U, backoff.getNextTimeout());
+    // Maxes out, and stays there, ad infinitum.
+    for (int i = 0; i < 10; i++) {
+        EXPECT_TRUE(backoff.hasNextTimeout());
+        EXPECT_EQ(0xffffffffU, backoff.getNextTimeout());
+    }
+}
+
+TEST(BackoffSequence, backoffToOncePerHour) {
+    auto backoff = BackoffSequence<uint32_t>::Builder()
+            .withInitialRetransmissionTime(1)
+            .withMaximumRetransmissionTime(3600)
+            .build();
+
+    EXPECT_TRUE(backoff.hasNextTimeout());
+    EXPECT_EQ(0x00000001U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000002U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000004U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000008U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000010U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000020U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000040U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000080U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000100U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000200U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000400U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000800U, backoff.getNextTimeout());
+    // Maxes out, and stays there, ad infinitum.
+    for (int i = 0; i < 10; i++) {
+        EXPECT_TRUE(backoff.hasNextTimeout());
+        EXPECT_EQ(3600U, backoff.getNextTimeout());
+    }
+}
+
+TEST(BackoffSequence, simpleMaxRetransCount) {
+    auto backoff = BackoffSequence<uint32_t>::Builder()
+            .withInitialRetransmissionTime(3)
+            .withMaximumRetransmissionCount(7)
+            .build();
+
+    EXPECT_TRUE(backoff.hasNextTimeout());
+    EXPECT_EQ(0x00000003U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000006U, backoff.getNextTimeout());
+    EXPECT_EQ(0x0000000cU, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000018U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000030U, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000060U, backoff.getNextTimeout());
+    EXPECT_EQ(0x000000c0U, backoff.getNextTimeout());
+
+    for (int i = 0; i < 10; i++) {
+        EXPECT_FALSE(backoff.hasNextTimeout());
+        EXPECT_EQ(backoff.getEndOfSequenceIndicator(), backoff.getNextTimeout());
+    }
+}
+
+TEST(BackoffSequence, simpleMaxDuration) {
+    auto backoff = BackoffSequence<int>::Builder()
+            .withInitialRetransmissionTime(3)
+            .withMaximumRetransmissionDuration(7)
+            .withEndOfSequenceIndicator(-1)
+            .build();
+
+    EXPECT_TRUE(backoff.hasNextTimeout());
+    EXPECT_EQ(0x00000003, backoff.getNextTimeout());
+    EXPECT_EQ(0x00000004, backoff.getNextTimeout());
+
+    for (int i = 0; i < 10; i++) {
+        EXPECT_FALSE(backoff.hasNextTimeout());
+        EXPECT_EQ(backoff.getEndOfSequenceIndicator(), backoff.getNextTimeout());
+        EXPECT_EQ(-1, backoff.getNextTimeout());
+    }
+}
+
+TEST(PathologicalBackoffSequence, ZeroInitialRetransTime) {
+    auto backoff = BackoffSequence<std::chrono::seconds>::Builder()
+            .withInitialRetransmissionTime(std::chrono::seconds(0))
+            .build();
+
+    for (int i = 0; i < 10; i++) {
+        // TODO: Decide whether this needs fixing, and how.
+        EXPECT_TRUE(backoff.hasNextTimeout());
+        EXPECT_EQ(backoff.getEndOfSequenceIndicator(), backoff.getNextTimeout());
+    }
+}
+
+TEST(PathologicalBackoffSequence, MaxRetransDurationGreaterThanInitialRetransTime) {
+    auto backoff = BackoffSequence<std::chrono::milliseconds>::Builder()
+            .withInitialRetransmissionTime(std::chrono::milliseconds(5))
+            .withMaximumRetransmissionDuration(std::chrono::milliseconds(3))
+            .build();
+
+    EXPECT_EQ(std::chrono::milliseconds(3), backoff.getNextTimeout());
+    for (int i = 0; i < 10; i++) {
+        EXPECT_FALSE(backoff.hasNextTimeout());
+        EXPECT_EQ(backoff.getEndOfSequenceIndicator(), backoff.getNextTimeout());
+    }
+}
+
+TEST(PathologicalBackoffSequence, MaxRetransDurationEqualsInitialRetransTime) {
+    auto backoff = BackoffSequence<std::chrono::hours>::Builder()
+            .withInitialRetransmissionTime(std::chrono::hours(5))
+            .withMaximumRetransmissionDuration(std::chrono::hours(5))
+            .build();
+
+    EXPECT_EQ(std::chrono::hours(5), backoff.getNextTimeout());
+    for (int i = 0; i < 10; i++) {
+        EXPECT_FALSE(backoff.hasNextTimeout());
+        EXPECT_EQ(backoff.getEndOfSequenceIndicator(), backoff.getNextTimeout());
+    }
+}
+
+TEST(PathologicalBackoffSequence, MaxRetransTimeAndDurationGreaterThanInitialRetransTime) {
+    auto backoff = BackoffSequence<std::chrono::nanoseconds>::Builder()
+            .withInitialRetransmissionTime(std::chrono::nanoseconds(7))
+            .withMaximumRetransmissionTime(std::chrono::nanoseconds(3))
+            .withMaximumRetransmissionDuration(std::chrono::nanoseconds(5))
+            .build();
+
+    EXPECT_EQ(std::chrono::nanoseconds(3), backoff.getNextTimeout());
+    EXPECT_EQ(std::chrono::nanoseconds(2), backoff.getNextTimeout());
+    for (int i = 0; i < 10; i++) {
+        EXPECT_FALSE(backoff.hasNextTimeout());
+        EXPECT_EQ(backoff.getEndOfSequenceIndicator(), backoff.getNextTimeout());
+    }
+}
+
+}  // namespace netdutils
+}  // namespace android
--- a/staticlibs/netd/libnetdutils/DumpWriter.cpp
+++ b/staticlibs/netd/libnetdutils/DumpWriter.cpp
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2016 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/DumpWriter.h"
+
+#include <unistd.h>
+#include <limits>
+
+#include <android-base/stringprintf.h>
+#include <utils/String8.h>
+
+using android::base::StringAppendV;
+
+namespace android {
+namespace netdutils {
+
+namespace {
+
+const char kIndentString[] = "  ";
+const size_t kIndentStringLen = strlen(kIndentString);
+
+}  // namespace
+
+DumpWriter::DumpWriter(int fd) : mIndentLevel(0), mFd(fd) {}
+
+void DumpWriter::incIndent() {
+    if (mIndentLevel < std::numeric_limits<decltype(mIndentLevel)>::max()) {
+        mIndentLevel++;
+    }
+}
+
+void DumpWriter::decIndent() {
+    if (mIndentLevel > std::numeric_limits<decltype(mIndentLevel)>::min()) {
+        mIndentLevel--;
+    }
+}
+
+void DumpWriter::println(const std::string& line) {
+    if (!line.empty()) {
+        for (int i = 0; i < mIndentLevel; i++) {
+            ::write(mFd, kIndentString, kIndentStringLen);
+        }
+        ::write(mFd, line.c_str(), line.size());
+    }
+    ::write(mFd, "\n", 1);
+}
+
+// NOLINTNEXTLINE(cert-dcl50-cpp): Grandfathered C-style variadic function.
+void DumpWriter::println(const char* fmt, ...) {
+    std::string line;
+    va_list ap;
+    va_start(ap, fmt);
+    StringAppendV(&line, fmt, ap);
+    va_end(ap);
+    println(line);
+}
+
+}  // namespace netdutils
+}  // namespace android
--- a/staticlibs/netd/libnetdutils/Fd.cpp
+++ b/staticlibs/netd/libnetdutils/Fd.cpp
@@ -0,0 +1,27 @@
+/*
+ * 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/Fd.h"
+
+namespace android {
+namespace netdutils {
+
+std::ostream& operator<<(std::ostream& os, const Fd& fd) {
+    return os << "Fd[" << fd.get() << "]";
+}
+
+}  // namespace netdutils
+}  // namespace android
--- a/staticlibs/netd/libnetdutils/FdTest.cpp
+++ b/staticlibs/netd/libnetdutils/FdTest.cpp
@@ -0,0 +1,147 @@
+/*
+ * 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 <cstdint>
+
+#include <gtest/gtest.h>
+
+#include "netdutils/MockSyscalls.h"
+#include "netdutils/Status.h"
+#include "netdutils/Syscalls.h"
+
+using testing::Mock;
+using testing::Return;
+using testing::StrictMock;
+
+namespace android {
+namespace netdutils {
+namespace {
+
+// Force implicit conversion from UniqueFd -> Fd
+inline Fd toFd(const UniqueFd& fd) {
+    return fd;
+}
+
+}  // namespace
+
+TEST(Fd, smoke) {
+    // Expect the following lines to compile
+    Fd fd1(1);
+    Fd fd2(fd1);
+    Fd fd3 = fd2;
+    const Fd fd4(8);
+    const Fd fd5(fd4);
+    const Fd fd6 = fd5;
+    EXPECT_TRUE(isWellFormed(fd3));
+    EXPECT_TRUE(isWellFormed(fd6));
+
+    // Corner case
+    Fd zero(0);
+    EXPECT_TRUE(isWellFormed(zero));
+
+    // Invalid file descriptors
+    Fd bad(-1);
+    Fd weird(-9);
+    EXPECT_FALSE(isWellFormed(bad));
+    EXPECT_FALSE(isWellFormed(weird));
+
+    // Default constructor
+    EXPECT_EQ(Fd(-1), Fd());
+    std::stringstream ss;
+    ss << fd3 << " " << fd6 << " " << bad << " " << weird;
+    EXPECT_EQ("Fd[1] Fd[8] Fd[-1] Fd[-9]", ss.str());
+}
+
+class UniqueFdTest : public testing::Test {
+  protected:
+    StrictMock<ScopedMockSyscalls> mSyscalls;
+};
+
+TEST_F(UniqueFdTest, operatorOstream) {
+    UniqueFd u(97);
+    EXPECT_CALL(mSyscalls, close(toFd(u))).WillOnce(Return(status::ok));
+    std::stringstream ss;
+    ss << u;
+    EXPECT_EQ("UniqueFd[Fd[97]]", ss.str());
+    u.reset();
+}
+
+TEST_F(UniqueFdTest, destructor) {
+    {
+        UniqueFd u(98);
+        EXPECT_CALL(mSyscalls, close(toFd(u))).WillOnce(Return(status::ok));
+    }
+    // Expectation above should be upon leaving nested scope
+    Mock::VerifyAndClearExpectations(&mSyscalls);
+}
+
+TEST_F(UniqueFdTest, reset) {
+    UniqueFd u(99);
+    EXPECT_CALL(mSyscalls, close(toFd(u))).WillOnce(Return(status::ok));
+    u.reset();
+
+    // Expectation above should be upon reset
+    Mock::VerifyAndClearExpectations(&mSyscalls);
+}
+
+TEST_F(UniqueFdTest, moveConstructor) {
+    constexpr Fd kFd(101);
+    UniqueFd u1(kFd);
+    {
+        UniqueFd u2(std::move(u1));
+        // NOLINTNEXTLINE bugprone-use-after-move
+        EXPECT_FALSE(isWellFormed(u1));
+        EXPECT_TRUE(isWellFormed(u2));
+        EXPECT_CALL(mSyscalls, close(kFd)).WillOnce(Return(status::ok));
+    }
+    // Expectation above should be upon leaving nested scope
+    Mock::VerifyAndClearExpectations(&mSyscalls);
+}
+
+TEST_F(UniqueFdTest, moveAssignment) {
+    constexpr Fd kFd(102);
+    UniqueFd u1(kFd);
+    {
+        UniqueFd u2 = std::move(u1);
+        // NOLINTNEXTLINE bugprone-use-after-move
+        EXPECT_FALSE(isWellFormed(u1));
+        EXPECT_TRUE(isWellFormed(u2));
+        UniqueFd u3;
+        u3 = std::move(u2);
+        // NOLINTNEXTLINE bugprone-use-after-move
+        EXPECT_FALSE(isWellFormed(u2));
+        EXPECT_TRUE(isWellFormed(u3));
+        EXPECT_CALL(mSyscalls, close(kFd)).WillOnce(Return(status::ok));
+    }
+    // Expectation above should be upon leaving nested scope
+    Mock::VerifyAndClearExpectations(&mSyscalls);
+}
+
+TEST_F(UniqueFdTest, constConstructor) {
+    constexpr Fd kFd(103);
+    const UniqueFd u(kFd);
+    EXPECT_CALL(mSyscalls, close(toFd(u))).WillOnce(Return(status::ok));
+}
+
+TEST_F(UniqueFdTest, closeFailure) {
+    constexpr Fd kFd(103);
+    UniqueFd u(kFd);
+    EXPECT_CALL(mSyscalls, close(toFd(u))).WillOnce(Return(statusFromErrno(EINTR, "test")));
+    EXPECT_DEBUG_DEATH(u.reset(), "");
+}
+
+}  // namespace netdutils
+}  // namespace android
--- a/staticlibs/netd/libnetdutils/InternetAddresses.cpp
+++ b/staticlibs/netd/libnetdutils/InternetAddresses.cpp
@@ -0,0 +1,164 @@
+/*
+ * 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 "netdutils/InternetAddresses.h"
+
+#include <string>
+
+#include <android-base/stringprintf.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+
+namespace android {
+
+using base::StringPrintf;
+
+namespace netdutils {
+
+std::string IPAddress::toString() const noexcept {
+    char repr[INET6_ADDRSTRLEN] = "\0";
+
+    switch (mData.family) {
+        case AF_UNSPEC:
+            return "<unspecified>";
+        case AF_INET: {
+            const in_addr v4 = mData.ip.v4;
+            inet_ntop(AF_INET, &v4, repr, sizeof(repr));
+            break;
+        }
+        case AF_INET6: {
+            const in6_addr v6 = mData.ip.v6;
+            inet_ntop(AF_INET6, &v6, repr, sizeof(repr));
+            break;
+        }
+        default:
+            return "<unknown_family>";
+    }
+
+    if (mData.family == AF_INET6 && mData.scope_id > 0) {
+        return StringPrintf("%s%%%u", repr, mData.scope_id);
+    }
+
+    return repr;
+}
+
+bool IPAddress::forString(const std::string& repr, IPAddress* ip) {
+    const addrinfo hints = {
+            .ai_flags = AI_NUMERICHOST | AI_NUMERICSERV,
+    };
+    addrinfo* res;
+    const int ret = getaddrinfo(repr.c_str(), nullptr, &hints, &res);
+    ScopedAddrinfo res_cleanup(res);
+    if (ret != 0) {
+        return false;
+    }
+
+    bool rval = true;
+    switch (res[0].ai_family) {
+        case AF_INET: {
+            sockaddr_in* sin = (sockaddr_in*) res[0].ai_addr;
+            if (ip) *ip = IPAddress(sin->sin_addr);
+            break;
+        }
+        case AF_INET6: {
+            sockaddr_in6* sin6 = (sockaddr_in6*) res[0].ai_addr;
+            if (ip) *ip = IPAddress(sin6->sin6_addr, sin6->sin6_scope_id);
+            break;
+        }
+        default:
+            rval = false;
+            break;
+    }
+
+    return rval;
+}
+
+IPPrefix::IPPrefix(const IPAddress& ip, int length) : IPPrefix(ip) {
+    // Silently treat CIDR lengths like "-1" as meaning the full bit length
+    // appropriate to the address family.
+    if (length < 0) return;
+    if (length >= mData.cidrlen) return;
+
+    switch (mData.family) {
+        case AF_UNSPEC:
+            break;
+        case AF_INET: {
+            const in_addr_t mask = (length > 0) ? (~0U) << (IPV4_ADDR_BITS - length) : 0U;
+            mData.ip.v4.s_addr &= htonl(mask);
+            mData.cidrlen = static_cast<uint8_t>(length);
+            break;
+        }
+        case AF_INET6: {
+            // The byte in which this CIDR length falls.
+            const int which = length / 8;
+            const int mask = (length % 8 == 0) ? 0 : 0xff << (8 - length % 8);
+            mData.ip.v6.s6_addr[which] &= mask;
+            for (int i = which + 1; i < IPV6_ADDR_LEN; i++) {
+                mData.ip.v6.s6_addr[i] = 0U;
+            }
+            mData.cidrlen = static_cast<uint8_t>(length);
+            break;
+        }
+        default:
+            // TODO: Complain bitterly about possible data corruption?
+            return;
+    }
+}
+
+bool IPPrefix::isUninitialized() const noexcept {
+    static const internal_::compact_ipdata empty{};
+    return mData == empty;
+}
+
+bool IPPrefix::forString(const std::string& repr, IPPrefix* prefix) {
+    size_t index = repr.find('/');
+    if (index == std::string::npos) return false;
+
+    // Parse the IP address.
+    IPAddress ip;
+    if (!IPAddress::forString(repr.substr(0, index), &ip)) return false;
+
+    // Parse the prefix length. Can't use base::ParseUint because it accepts non-base 10 input.
+    const char* prefixString = repr.c_str() + index + 1;
+    if (!isdigit(*prefixString)) return false;
+    char* endptr;
+    unsigned long prefixlen = strtoul(prefixString, &endptr, 10);
+    if (*endptr != '\0') return false;
+
+    uint8_t maxlen = (ip.family() == AF_INET) ? 32 : 128;
+    if (prefixlen > maxlen) return false;
+
+    *prefix = IPPrefix(ip, prefixlen);
+    return true;
+}
+
+std::string IPPrefix::toString() const noexcept {
+    return StringPrintf("%s/%d", ip().toString().c_str(), mData.cidrlen);
+}
+
+std::string IPSockAddr::toString() const noexcept {
+    switch (mData.family) {
+        case AF_INET6:
+            return StringPrintf("[%s]:%u", ip().toString().c_str(), mData.port);
+        default:
+            return StringPrintf("%s:%u", ip().toString().c_str(), mData.port);
+    }
+}
+
+}  // namespace netdutils
+}  // namespace android
--- a/staticlibs/netd/libnetdutils/InternetAddressesTest.cpp
+++ b/staticlibs/netd/libnetdutils/InternetAddressesTest.cpp
@@ -0,0 +1,541 @@
+/*
+ * 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 <cstdint>
+#include <limits>
+#include <sstream>
+#include <string>
+#include <vector>
+
+#include <android-base/macros.h>
+#include <gtest/gtest.h>
+
+#include "netdutils/InternetAddresses.h"
+
+namespace android {
+namespace netdutils {
+namespace {
+
+enum Relation { EQ, LT };
+
+std::ostream& operator<<(std::ostream& os, Relation relation) {
+    switch (relation) {
+        case EQ: os << "eq"; break;
+        case LT: os << "lt"; break;
+        default: os << "?!"; break;
+    }
+    return os;
+}
+
+template <typename T>
+struct OperatorExpectation {
+    const Relation relation;
+    const T obj1;
+    const T obj2;
+
+    std::string toString() const {
+        std::stringstream output;
+        output << obj1 << " " << relation << " " << obj2;
+        return output.str();
+    }
+};
+
+template <typename T>
+void testGamutOfOperators(const OperatorExpectation<T>& expectation) {
+    switch (expectation.relation) {
+        case EQ:
+            EXPECT_TRUE(expectation.obj1 == expectation.obj2);
+            EXPECT_TRUE(expectation.obj1 <= expectation.obj2);
+            EXPECT_TRUE(expectation.obj1 >= expectation.obj2);
+            EXPECT_FALSE(expectation.obj1 != expectation.obj2);
+            EXPECT_FALSE(expectation.obj1 < expectation.obj2);
+            EXPECT_FALSE(expectation.obj1 > expectation.obj2);
+            break;
+
+        case LT:
+            EXPECT_TRUE(expectation.obj1 < expectation.obj2);
+            EXPECT_TRUE(expectation.obj1 <= expectation.obj2);
+            EXPECT_TRUE(expectation.obj1 != expectation.obj2);
+            EXPECT_FALSE(expectation.obj1 > expectation.obj2);
+            EXPECT_FALSE(expectation.obj1 >= expectation.obj2);
+            EXPECT_FALSE(expectation.obj1 == expectation.obj2);
+            break;
+
+        default:
+            FAIL() << "Unknown relation given in test expectation";
+    }
+}
+
+const in_addr IPV4_ANY{htonl(INADDR_ANY)};
+const in_addr IPV4_LOOPBACK{htonl(INADDR_LOOPBACK)};
+const in_addr IPV4_ONES{~0U};
+const in6_addr IPV6_ANY = IN6ADDR_ANY_INIT;
+const in6_addr IPV6_LOOPBACK = IN6ADDR_LOOPBACK_INIT;
+const in6_addr FE80{{{0xfe,0x80,0,0,0,0,0,0,0,0,0,0,0,0,0,0}}};
+const in6_addr FE80_1{{{0xfe,0x80,0,0,0,0,0,0,0,0,0,0,0,0,0,1}}};
+const in6_addr FE80_2{{{0xfe,0x80,0,0,0,0,0,0,0,0,0,0,0,0,0,2}}};
+const uint8_t ff = std::numeric_limits<uint8_t>::max();
+const in6_addr IPV6_ONES{{{ff,ff,ff,ff,ff,ff,ff,ff,ff,ff,ff,ff,ff,ff,ff,ff}}};
+
+TEST(IPAddressTest, GamutOfOperators) {
+    const std::vector<OperatorExpectation<IPAddress>> kExpectations{
+            {EQ, IPAddress(), IPAddress()},
+            {EQ, IPAddress(IPV4_ONES), IPAddress(IPV4_ONES)},
+            {EQ, IPAddress(IPV6_ONES), IPAddress(IPV6_ONES)},
+            {EQ, IPAddress(FE80_1), IPAddress(FE80_1)},
+            {EQ, IPAddress(FE80_2), IPAddress(FE80_2)},
+            {LT, IPAddress(), IPAddress(IPV4_ANY)},
+            {LT, IPAddress(), IPAddress(IPV4_ONES)},
+            {LT, IPAddress(), IPAddress(IPV6_ANY)},
+            {LT, IPAddress(), IPAddress(IPV6_ONES)},
+            {LT, IPAddress(IPV4_ANY), IPAddress(IPV4_ONES)},
+            {LT, IPAddress(IPV4_ANY), IPAddress(IPV6_ANY)},
+            {LT, IPAddress(IPV4_ONES), IPAddress(IPV6_ANY)},
+            {LT, IPAddress(IPV4_ONES), IPAddress(IPV6_ONES)},
+            {LT, IPAddress(IPV6_ANY), IPAddress(IPV6_LOOPBACK)},
+            {LT, IPAddress(IPV6_ANY), IPAddress(IPV6_ONES)},
+            {LT, IPAddress(IPV6_LOOPBACK), IPAddress(IPV6_ONES)},
+            {LT, IPAddress(FE80_1), IPAddress(FE80_2)},
+            {LT, IPAddress(FE80_1), IPAddress(IPV6_ONES)},
+            {LT, IPAddress(FE80_2), IPAddress(IPV6_ONES)},
+            // Sort by scoped_id within the same address.
+            {LT, IPAddress(FE80_1), IPAddress(FE80_1, 1)},
+            {LT, IPAddress(FE80_1, 1), IPAddress(FE80_1, 2)},
+            // Sort by address first, scope_id second.
+            {LT, IPAddress(FE80_1, 2), IPAddress(FE80_2, 1)},
+    };
+
+    size_t tests_run = 0;
+    for (const auto& expectation : kExpectations) {
+        SCOPED_TRACE(expectation.toString());
+        EXPECT_NO_FATAL_FAILURE(testGamutOfOperators(expectation));
+        tests_run++;
+    }
+    EXPECT_EQ(kExpectations.size(), tests_run);
+}
+
+TEST(IPAddressTest, ScopeIds) {
+    // Scope IDs ignored for IPv4 addresses.
+    const IPAddress ones(IPV4_ONES);
+    EXPECT_EQ(0U, ones.scope_id());
+    const IPAddress ones22(ones, 22);
+    EXPECT_EQ(0U, ones22.scope_id());
+    EXPECT_EQ(ones, ones22);
+    const IPAddress ones23(ones, 23);
+    EXPECT_EQ(0U, ones23.scope_id());
+    EXPECT_EQ(ones22, ones23);
+
+    EXPECT_EQ("fe80::1%22", IPAddress(FE80_1, 22).toString());
+    EXPECT_EQ("fe80::2%23", IPAddress(FE80_2, 23).toString());
+
+    // Verify that given an IPAddress with a scope_id an address without a
+    // scope_id can be constructed (just in case it's useful).
+    const IPAddress fe80_intf22(FE80_1, 22);
+    EXPECT_EQ(22U, fe80_intf22.scope_id());
+    EXPECT_EQ(fe80_intf22, IPAddress(fe80_intf22));
+    EXPECT_EQ(IPAddress(FE80_1), IPAddress(fe80_intf22, 0));
+}
+
+TEST(IPAddressTest, forString) {
+    IPAddress ip;
+
+    EXPECT_FALSE(IPAddress::forString("not_an_ip", &ip));
+    EXPECT_FALSE(IPAddress::forString("not_an_ip", nullptr));
+    EXPECT_EQ(IPAddress(), IPAddress::forString("not_an_ip"));
+
+    EXPECT_EQ(IPAddress(IPV4_ANY), IPAddress::forString("0.0.0.0"));
+    EXPECT_EQ(IPAddress(IPV4_ONES), IPAddress::forString("255.255.255.255"));
+    EXPECT_EQ(IPAddress(IPV4_LOOPBACK), IPAddress::forString("127.0.0.1"));
+
+    EXPECT_EQ(IPAddress(IPV6_ANY), IPAddress::forString("::"));
+    EXPECT_EQ(IPAddress(IPV6_ANY), IPAddress::forString("::0"));
+    EXPECT_EQ(IPAddress(IPV6_ANY), IPAddress::forString("0::"));
+    EXPECT_EQ(IPAddress(IPV6_LOOPBACK), IPAddress::forString("::1"));
+    EXPECT_EQ(IPAddress(IPV6_LOOPBACK), IPAddress::forString("0::1"));
+    EXPECT_EQ(IPAddress(FE80_1), IPAddress::forString("fe80::1"));
+    EXPECT_EQ(IPAddress(FE80_1, 22), IPAddress::forString("fe80::1%22"));
+    // This relies upon having a loopback interface named "lo" with ifindex 1.
+    EXPECT_EQ(IPAddress(FE80_1, 1), IPAddress::forString("fe80::1%lo"));
+}
+
+TEST(IPPrefixTest, forString) {
+    IPPrefix prefix;
+
+    EXPECT_FALSE(IPPrefix::forString("", &prefix));
+    EXPECT_FALSE(IPPrefix::forString("invalid", &prefix));
+    EXPECT_FALSE(IPPrefix::forString("192.0.2.0", &prefix));
+    EXPECT_FALSE(IPPrefix::forString("2001::db8::", &prefix));
+
+    EXPECT_FALSE(IPPrefix::forString("2001:db8::/", &prefix));
+    EXPECT_FALSE(IPPrefix::forString("2001:db8:://32", &prefix));
+    EXPECT_FALSE(IPPrefix::forString("2001:db8::/32z", &prefix));
+    EXPECT_FALSE(IPPrefix::forString("2001:db8::/32/", &prefix));
+    EXPECT_FALSE(IPPrefix::forString("2001:db8::/0x20", &prefix));
+    EXPECT_FALSE(IPPrefix::forString("2001:db8:: /32", &prefix));
+    EXPECT_FALSE(IPPrefix::forString("2001:db8::/ 32", &prefix));
+    EXPECT_FALSE(IPPrefix::forString(" 2001:db8::/32", &prefix));
+    EXPECT_FALSE(IPPrefix::forString("2001:db8::/32 ", &prefix));
+    EXPECT_FALSE(IPPrefix::forString("2001:db8::/+32", &prefix));
+
+    EXPECT_FALSE(IPPrefix::forString("192.0.2.0/33", &prefix));
+    EXPECT_FALSE(IPPrefix::forString("2001:db8::/129", &prefix));
+    EXPECT_FALSE(IPPrefix::forString("192.0.2.0/-1", &prefix));
+    EXPECT_FALSE(IPPrefix::forString("2001:db8::/-1", &prefix));
+
+    EXPECT_TRUE(IPPrefix::forString("2001:db8::/32", &prefix));
+    EXPECT_EQ("2001:db8::/32", prefix.toString());
+    EXPECT_EQ(IPPrefix(IPAddress::forString("2001:db8::"), 32), prefix);
+
+    EXPECT_EQ(IPPrefix(), IPPrefix::forString("invalid"));
+
+    EXPECT_EQ("0.0.0.0/0", IPPrefix::forString("0.0.0.0/0").toString());
+    EXPECT_EQ("::/0", IPPrefix::forString("::/0").toString());
+    EXPECT_EQ("192.0.2.128/25", IPPrefix::forString("192.0.2.131/25").toString());
+    EXPECT_EQ("2001:db8:1:2:3:4:5:4/126",
+              IPPrefix::forString("2001:db8:1:2:3:4:5:6/126").toString());
+}
+
+TEST(IPPrefixTest, IPv4Truncation) {
+    const auto prefixStr = [](int length) -> std::string {
+        return IPPrefix(IPAddress(IPV4_ONES), length).toString();
+    };
+
+    EXPECT_EQ("0.0.0.0/0", prefixStr(0));
+
+    EXPECT_EQ("128.0.0.0/1", prefixStr(1));
+    EXPECT_EQ("192.0.0.0/2", prefixStr(2));
+    EXPECT_EQ("224.0.0.0/3", prefixStr(3));
+    EXPECT_EQ("240.0.0.0/4", prefixStr(4));
+    EXPECT_EQ("248.0.0.0/5", prefixStr(5));
+    EXPECT_EQ("252.0.0.0/6", prefixStr(6));
+    EXPECT_EQ("254.0.0.0/7", prefixStr(7));
+    EXPECT_EQ("255.0.0.0/8", prefixStr(8));
+
+    EXPECT_EQ("255.128.0.0/9", prefixStr(9));
+    EXPECT_EQ("255.192.0.0/10", prefixStr(10));
+    EXPECT_EQ("255.224.0.0/11", prefixStr(11));
+    EXPECT_EQ("255.240.0.0/12", prefixStr(12));
+    EXPECT_EQ("255.248.0.0/13", prefixStr(13));
+    EXPECT_EQ("255.252.0.0/14", prefixStr(14));
+    EXPECT_EQ("255.254.0.0/15", prefixStr(15));
+    EXPECT_EQ("255.255.0.0/16", prefixStr(16));
+
+    EXPECT_EQ("255.255.128.0/17", prefixStr(17));
+    EXPECT_EQ("255.255.192.0/18", prefixStr(18));
+    EXPECT_EQ("255.255.224.0/19", prefixStr(19));
+    EXPECT_EQ("255.255.240.0/20", prefixStr(20));
+    EXPECT_EQ("255.255.248.0/21", prefixStr(21));
+    EXPECT_EQ("255.255.252.0/22", prefixStr(22));
+    EXPECT_EQ("255.255.254.0/23", prefixStr(23));
+    EXPECT_EQ("255.255.255.0/24", prefixStr(24));
+
+    EXPECT_EQ("255.255.255.128/25", prefixStr(25));
+    EXPECT_EQ("255.255.255.192/26", prefixStr(26));
+    EXPECT_EQ("255.255.255.224/27", prefixStr(27));
+    EXPECT_EQ("255.255.255.240/28", prefixStr(28));
+    EXPECT_EQ("255.255.255.248/29", prefixStr(29));
+    EXPECT_EQ("255.255.255.252/30", prefixStr(30));
+    EXPECT_EQ("255.255.255.254/31", prefixStr(31));
+    EXPECT_EQ("255.255.255.255/32", prefixStr(32));
+}
+
+TEST(IPPrefixTest, IPv6Truncation) {
+    const auto prefixStr = [](int length) -> std::string {
+        return IPPrefix(IPAddress(IPV6_ONES), length).toString();
+    };
+
+    EXPECT_EQ("::/0", prefixStr(0));
+
+    EXPECT_EQ("8000::/1", prefixStr(1));
+    EXPECT_EQ("c000::/2", prefixStr(2));
+    EXPECT_EQ("e000::/3", prefixStr(3));
+    EXPECT_EQ("f000::/4", prefixStr(4));
+    EXPECT_EQ("f800::/5", prefixStr(5));
+    EXPECT_EQ("fc00::/6", prefixStr(6));
+    EXPECT_EQ("fe00::/7", prefixStr(7));
+    EXPECT_EQ("ff00::/8", prefixStr(8));
+
+    EXPECT_EQ("ff80::/9", prefixStr(9));
+    EXPECT_EQ("ffc0::/10", prefixStr(10));
+    EXPECT_EQ("ffe0::/11", prefixStr(11));
+    EXPECT_EQ("fff0::/12", prefixStr(12));
+    EXPECT_EQ("fff8::/13", prefixStr(13));
+    EXPECT_EQ("fffc::/14", prefixStr(14));
+    EXPECT_EQ("fffe::/15", prefixStr(15));
+    EXPECT_EQ("ffff::/16", prefixStr(16));
+
+    EXPECT_EQ("ffff:8000::/17", prefixStr(17));
+    EXPECT_EQ("ffff:c000::/18", prefixStr(18));
+    EXPECT_EQ("ffff:e000::/19", prefixStr(19));
+    EXPECT_EQ("ffff:f000::/20", prefixStr(20));
+    EXPECT_EQ("ffff:f800::/21", prefixStr(21));
+    EXPECT_EQ("ffff:fc00::/22", prefixStr(22));
+    EXPECT_EQ("ffff:fe00::/23", prefixStr(23));
+    EXPECT_EQ("ffff:ff00::/24", prefixStr(24));
+
+    EXPECT_EQ("ffff:ff80::/25", prefixStr(25));
+    EXPECT_EQ("ffff:ffc0::/26", prefixStr(26));
+    EXPECT_EQ("ffff:ffe0::/27", prefixStr(27));
+    EXPECT_EQ("ffff:fff0::/28", prefixStr(28));
+    EXPECT_EQ("ffff:fff8::/29", prefixStr(29));
+    EXPECT_EQ("ffff:fffc::/30", prefixStr(30));
+    EXPECT_EQ("ffff:fffe::/31", prefixStr(31));
+    EXPECT_EQ("ffff:ffff::/32", prefixStr(32));
+
+    EXPECT_EQ("ffff:ffff:8000::/33", prefixStr(33));
+    EXPECT_EQ("ffff:ffff:c000::/34", prefixStr(34));
+    EXPECT_EQ("ffff:ffff:e000::/35", prefixStr(35));
+    EXPECT_EQ("ffff:ffff:f000::/36", prefixStr(36));
+    EXPECT_EQ("ffff:ffff:f800::/37", prefixStr(37));
+    EXPECT_EQ("ffff:ffff:fc00::/38", prefixStr(38));
+    EXPECT_EQ("ffff:ffff:fe00::/39", prefixStr(39));
+    EXPECT_EQ("ffff:ffff:ff00::/40", prefixStr(40));
+
+    EXPECT_EQ("ffff:ffff:ff80::/41", prefixStr(41));
+    EXPECT_EQ("ffff:ffff:ffc0::/42", prefixStr(42));
+    EXPECT_EQ("ffff:ffff:ffe0::/43", prefixStr(43));
+    EXPECT_EQ("ffff:ffff:fff0::/44", prefixStr(44));
+    EXPECT_EQ("ffff:ffff:fff8::/45", prefixStr(45));
+    EXPECT_EQ("ffff:ffff:fffc::/46", prefixStr(46));
+    EXPECT_EQ("ffff:ffff:fffe::/47", prefixStr(47));
+    EXPECT_EQ("ffff:ffff:ffff::/48", prefixStr(48));
+
+    EXPECT_EQ("ffff:ffff:ffff:8000::/49", prefixStr(49));
+    EXPECT_EQ("ffff:ffff:ffff:c000::/50", prefixStr(50));
+    EXPECT_EQ("ffff:ffff:ffff:e000::/51", prefixStr(51));
+    EXPECT_EQ("ffff:ffff:ffff:f000::/52", prefixStr(52));
+    EXPECT_EQ("ffff:ffff:ffff:f800::/53", prefixStr(53));
+    EXPECT_EQ("ffff:ffff:ffff:fc00::/54", prefixStr(54));
+    EXPECT_EQ("ffff:ffff:ffff:fe00::/55", prefixStr(55));
+    EXPECT_EQ("ffff:ffff:ffff:ff00::/56", prefixStr(56));
+
+    EXPECT_EQ("ffff:ffff:ffff:ff80::/57", prefixStr(57));
+    EXPECT_EQ("ffff:ffff:ffff:ffc0::/58", prefixStr(58));
+    EXPECT_EQ("ffff:ffff:ffff:ffe0::/59", prefixStr(59));
+    EXPECT_EQ("ffff:ffff:ffff:fff0::/60", prefixStr(60));
+    EXPECT_EQ("ffff:ffff:ffff:fff8::/61", prefixStr(61));
+    EXPECT_EQ("ffff:ffff:ffff:fffc::/62", prefixStr(62));
+    EXPECT_EQ("ffff:ffff:ffff:fffe::/63", prefixStr(63));
+    EXPECT_EQ("ffff:ffff:ffff:ffff::/64", prefixStr(64));
+
+    EXPECT_EQ("ffff:ffff:ffff:ffff:8000::/65", prefixStr(65));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:c000::/66", prefixStr(66));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:e000::/67", prefixStr(67));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:f000::/68", prefixStr(68));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:f800::/69", prefixStr(69));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:fc00::/70", prefixStr(70));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:fe00::/71", prefixStr(71));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ff00::/72", prefixStr(72));
+
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ff80::/73", prefixStr(73));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffc0::/74", prefixStr(74));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffe0::/75", prefixStr(75));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:fff0::/76", prefixStr(76));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:fff8::/77", prefixStr(77));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:fffc::/78", prefixStr(78));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:fffe::/79", prefixStr(79));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff::/80", prefixStr(80));
+
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:8000::/81", prefixStr(81));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:c000::/82", prefixStr(82));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:e000::/83", prefixStr(83));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:f000::/84", prefixStr(84));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:f800::/85", prefixStr(85));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:fc00::/86", prefixStr(86));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:fe00::/87", prefixStr(87));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ff00::/88", prefixStr(88));
+
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ff80::/89", prefixStr(89));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffc0::/90", prefixStr(90));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffe0::/91", prefixStr(91));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:fff0::/92", prefixStr(92));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:fff8::/93", prefixStr(93));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:fffc::/94", prefixStr(94));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:fffe::/95", prefixStr(95));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff::/96", prefixStr(96));
+
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:8000:0/97", prefixStr(97));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:c000:0/98", prefixStr(98));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:e000:0/99", prefixStr(99));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:f000:0/100", prefixStr(100));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:f800:0/101", prefixStr(101));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:fc00:0/102", prefixStr(102));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:fe00:0/103", prefixStr(103));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:ff00:0/104", prefixStr(104));
+
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:ff80:0/105", prefixStr(105));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:ffc0:0/106", prefixStr(106));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:ffe0:0/107", prefixStr(107));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:fff0:0/108", prefixStr(108));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:fff8:0/109", prefixStr(109));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:fffc:0/110", prefixStr(110));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:fffe:0/111", prefixStr(111));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:ffff:0/112", prefixStr(112));
+
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:ffff:8000/113", prefixStr(113));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:ffff:c000/114", prefixStr(114));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:ffff:e000/115", prefixStr(115));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:ffff:f000/116", prefixStr(116));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:ffff:f800/117", prefixStr(117));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:ffff:fc00/118", prefixStr(118));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:ffff:fe00/119", prefixStr(119));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ff00/120", prefixStr(120));
+
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ff80/121", prefixStr(121));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffc0/122", prefixStr(122));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffe0/123", prefixStr(123));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:ffff:fff0/124", prefixStr(124));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:ffff:fff8/125", prefixStr(125));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:ffff:fffc/126", prefixStr(126));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:ffff:fffe/127", prefixStr(127));
+    EXPECT_EQ("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff/128", prefixStr(128));
+}
+
+TEST(IPPrefixTest, TruncationOther) {
+    const struct {
+        const char* ip;
+        const int cidrLen;
+        const char* ipTruncated;
+    } testExpectations[] = {
+            {"192.0.2.0", 24, "192.0.2.0"},
+            {"192.0.2.0", 23, "192.0.2.0"},
+            {"192.0.2.0", 22, "192.0.0.0"},
+            {"192.0.2.0", 1, "128.0.0.0"},
+            {"2001:db8:cafe:d00d::", 56, "2001:db8:cafe:d000::"},
+            {"2001:db8:cafe:d00d::", 48, "2001:db8:cafe::"},
+            {"2001:db8:cafe:d00d::", 47, "2001:db8:cafe::"},
+            {"2001:db8:cafe:d00d::", 46, "2001:db8:cafc::"},
+    };
+
+    for (const auto& expectation : testExpectations) {
+        IPAddress ip;
+        EXPECT_TRUE(IPAddress::forString(expectation.ip, &ip))
+                << "Failed to parse IP address " << expectation.ip;
+
+        IPAddress ipTruncated;
+        EXPECT_TRUE(IPAddress::forString(expectation.ipTruncated, &ipTruncated))
+                << "Failed to parse IP address " << expectation.ipTruncated;
+
+        IPPrefix prefix(ip, expectation.cidrLen);
+
+        EXPECT_EQ(expectation.cidrLen, prefix.length())
+                << "Unexpected cidrLen " << expectation.cidrLen;
+        EXPECT_EQ(ipTruncated, prefix.ip())
+                << "Unexpected IP truncation: " << prefix.ip() << ", expected: " << ipTruncated;
+    }
+}
+
+TEST(IPPrefixTest, GamutOfOperators) {
+    const std::vector<OperatorExpectation<IPPrefix>> kExpectations{
+            {EQ, IPPrefix(), IPPrefix()},
+            {EQ, IPPrefix(IPAddress(IPV4_ANY), 0), IPPrefix(IPAddress(IPV4_ANY), 0)},
+            {EQ, IPPrefix(IPAddress(IPV4_ANY), IPV4_ADDR_BITS), IPPrefix(IPAddress(IPV4_ANY))},
+            {EQ, IPPrefix(IPAddress(IPV6_ANY), 0), IPPrefix(IPAddress(IPV6_ANY), 0)},
+            {EQ, IPPrefix(IPAddress(IPV6_ANY), IPV6_ADDR_BITS), IPPrefix(IPAddress(IPV6_ANY))},
+            // Needlessly fully-specified IPv6 link-local address.
+            {EQ, IPPrefix(IPAddress(FE80_1)), IPPrefix(IPAddress(FE80_1, 0), IPV6_ADDR_BITS)},
+            // Different IPv6 link-local addresses within the same /64, no scoped_id: same /64.
+            {EQ, IPPrefix(IPAddress(FE80_1), 64), IPPrefix(IPAddress(FE80_2), 64)},
+            // Different IPv6 link-local address within the same /64, same scoped_id: same /64.
+            {EQ, IPPrefix(IPAddress(FE80_1, 17), 64), IPPrefix(IPAddress(FE80_2, 17), 64)},
+            // Unspecified < IPv4.
+            {LT, IPPrefix(), IPPrefix(IPAddress(IPV4_ANY), 0)},
+            // Same IPv4 base address sorts by prefix length.
+            {LT, IPPrefix(IPAddress(IPV4_ANY), 0), IPPrefix(IPAddress(IPV4_ANY), 1)},
+            {LT, IPPrefix(IPAddress(IPV4_ANY), 1), IPPrefix(IPAddress(IPV4_ANY), IPV4_ADDR_BITS)},
+            // Truncation means each base IPv4 address is different.
+            {LT, IPPrefix(IPAddress(IPV4_ONES), 0), IPPrefix(IPAddress(IPV4_ONES), 1)},
+            {LT, IPPrefix(IPAddress(IPV4_ONES), 1), IPPrefix(IPAddress(IPV4_ONES), IPV4_ADDR_BITS)},
+            // Sort by base IPv4 addresses first.
+            {LT, IPPrefix(IPAddress(IPV4_ANY), 0), IPPrefix(IPAddress::forString("0.0.0.1"))},
+            {LT, IPPrefix(IPAddress(IPV4_ANY), 1), IPPrefix(IPAddress::forString("0.0.0.1"))},
+            {LT, IPPrefix(IPAddress(IPV4_ANY), 24), IPPrefix(IPAddress::forString("0.0.0.1"))},
+            // IPv4 < IPv6.
+            {LT, IPPrefix(IPAddress(IPV4_ANY), 0), IPPrefix(IPAddress(IPV6_ANY), 0)},
+            {LT, IPPrefix(IPAddress(IPV4_ONES)), IPPrefix(IPAddress(IPV6_ANY))},
+            // Unspecified < IPv6.
+            {LT, IPPrefix(), IPPrefix(IPAddress(IPV6_ANY), 0)},
+            // Same IPv6 base address sorts by prefix length.
+            {LT, IPPrefix(IPAddress(IPV6_ANY), 0), IPPrefix(IPAddress(IPV6_ANY), 1)},
+            {LT, IPPrefix(IPAddress(IPV6_ANY), 1), IPPrefix(IPAddress(IPV6_ANY), IPV6_ADDR_BITS)},
+            // Truncation means each base IPv6 address is different.
+            {LT, IPPrefix(IPAddress(IPV6_ONES), 0), IPPrefix(IPAddress(IPV6_ONES), 1)},
+            {LT, IPPrefix(IPAddress(IPV6_ONES), 1), IPPrefix(IPAddress(IPV6_ONES), IPV6_ADDR_BITS)},
+            // Different IPv6 link-local address in same /64, different scoped_id: different /64.
+            {LT, IPPrefix(IPAddress(FE80_1, 17), 64), IPPrefix(IPAddress(FE80_2, 22), 64)},
+            {LT, IPPrefix(IPAddress(FE80_1, 17), 64), IPPrefix(IPAddress(FE80_1, 18), 64)},
+            {LT, IPPrefix(IPAddress(FE80_1, 18), 64), IPPrefix(IPAddress(FE80_1, 19), 64)},
+    };
+
+    size_t tests_run = 0;
+    for (const auto& expectation : kExpectations) {
+        SCOPED_TRACE(expectation.toString());
+        EXPECT_NO_FATAL_FAILURE(testGamutOfOperators(expectation));
+        tests_run++;
+    }
+    EXPECT_EQ(kExpectations.size(), tests_run);
+}
+
+TEST(IPSockAddrTest, GamutOfOperators) {
+    const std::vector<OperatorExpectation<IPSockAddr>> kExpectations{
+            {EQ, IPSockAddr(), IPSockAddr()},
+            {EQ, IPSockAddr(IPAddress(IPV4_ANY)), IPSockAddr(IPAddress(IPV4_ANY), 0)},
+            {EQ, IPSockAddr(IPAddress(IPV6_ANY)), IPSockAddr(IPAddress(IPV6_ANY), 0)},
+            {EQ, IPSockAddr(IPAddress(FE80_1), 80), IPSockAddr(IPAddress(FE80_1), 80)},
+            {EQ, IPSockAddr(IPAddress(FE80_1, 17)), IPSockAddr(IPAddress(FE80_1, 17), 0)},
+            {LT, IPSockAddr(IPAddress(IPV4_ANY), 0), IPSockAddr(IPAddress(IPV4_ANY), 1)},
+            {LT, IPSockAddr(IPAddress(IPV4_ANY), 53), IPSockAddr(IPAddress(IPV4_ANY), 123)},
+            {LT, IPSockAddr(IPAddress(IPV4_ONES), 123), IPSockAddr(IPAddress(IPV6_ANY), 53)},
+            {LT, IPSockAddr(IPAddress(IPV6_ANY), 0), IPSockAddr(IPAddress(IPV6_ANY), 1)},
+            {LT, IPSockAddr(IPAddress(IPV6_ANY), 53), IPSockAddr(IPAddress(IPV6_ANY), 123)},
+            {LT, IPSockAddr(IPAddress(FE80_1), 80), IPSockAddr(IPAddress(FE80_1, 17), 80)},
+            {LT, IPSockAddr(IPAddress(FE80_1, 17), 80), IPSockAddr(IPAddress(FE80_1, 22), 80)},
+    };
+
+    size_t tests_run = 0;
+    for (const auto& expectation : kExpectations) {
+        SCOPED_TRACE(expectation.toString());
+        EXPECT_NO_FATAL_FAILURE(testGamutOfOperators(expectation));
+        tests_run++;
+    }
+    EXPECT_EQ(kExpectations.size(), tests_run);
+}
+
+TEST(IPSockAddrTest, toString) {
+    EXPECT_EQ("<unspecified>:0", IPSockAddr().toString());
+    EXPECT_EQ("0.0.0.0:0", IPSockAddr(IPAddress(IPV4_ANY)).toString());
+    EXPECT_EQ("255.255.255.255:67", IPSockAddr(IPAddress(IPV4_ONES), 67).toString());
+    EXPECT_EQ("[::]:0", IPSockAddr(IPAddress(IPV6_ANY)).toString());
+    EXPECT_EQ("[::1]:53", IPSockAddr(IPAddress(IPV6_LOOPBACK), 53).toString());
+    EXPECT_EQ("[fe80::1]:0", IPSockAddr(IPAddress(FE80_1)).toString());
+    EXPECT_EQ("[fe80::2%17]:123", IPSockAddr(IPAddress(FE80_2, 17), 123).toString());
+}
+
+TEST(CompatIPDataTest, ConversionsClearUnneededValues) {
+    const uint32_t idx = 17;
+    const IPSockAddr linkLocalNtpSockaddr(IPAddress(FE80_2, idx), 123);
+    EXPECT_EQ(IPAddress(FE80_2, idx), linkLocalNtpSockaddr.ip());
+    // IPSockAddr(IPSockaddr.ip()) see the port cleared.
+    EXPECT_EQ(0, IPSockAddr(linkLocalNtpSockaddr.ip()).port());
+    const IPPrefix linkLocalPrefix(linkLocalNtpSockaddr.ip(), 64);
+    EXPECT_EQ(IPAddress(FE80, idx), linkLocalPrefix.ip());
+    // IPPrefix(IPPrefix.ip()) see the CIDR length cleared.
+    EXPECT_EQ(IPV6_ADDR_BITS, IPPrefix(linkLocalPrefix.ip()).length());
+}
+
+}  // namespace
+}  // namespace netdutils
+}  // namespace android
--- a/staticlibs/netd/libnetdutils/Log.cpp
+++ b/staticlibs/netd/libnetdutils/Log.cpp
@@ -0,0 +1,216 @@
+/*
+ * 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 "netdutils/Log.h"
+#include "netdutils/Slice.h"
+
+#include <chrono>
+#include <ctime>
+#include <iomanip>
+#include <mutex>
+#include <sstream>
+
+#include <android-base/strings.h>
+#include <log/log.h>
+
+using ::android::base::Join;
+using ::android::base::StringPrintf;
+
+namespace android {
+namespace netdutils {
+
+namespace {
+
+std::string makeTimestampedEntry(const std::string& entry) {
+    using ::std::chrono::duration_cast;
+    using ::std::chrono::milliseconds;
+    using ::std::chrono::system_clock;
+
+    std::stringstream tsEntry;
+    const auto now = system_clock::now();
+    const auto time_sec = system_clock::to_time_t(now);
+    tsEntry << std::put_time(std::localtime(&time_sec), "%m-%d %H:%M:%S.") << std::setw(3)
+            << std::setfill('0')
+            << duration_cast<milliseconds>(now - system_clock::from_time_t(time_sec)).count() << " "
+            << entry;
+
+    return tsEntry.str();
+}
+
+}  // namespace
+
+std::string LogEntry::toString() const {
+    std::vector<std::string> text;
+
+    if (!mMsg.empty()) text.push_back(mMsg);
+    if (!mFunc.empty()) {
+        text.push_back(StringPrintf("%s(%s)", mFunc.c_str(), Join(mArgs, ", ").c_str()));
+    }
+    if (!mReturns.empty()) {
+        text.push_back("->");
+        text.push_back(StringPrintf("(%s)", Join(mReturns, ", ").c_str()));
+    }
+    if (!mUid.empty()) text.push_back(mUid);
+    if (!mDuration.empty()) text.push_back(StringPrintf("(%s)", mDuration.c_str()));
+
+    return Join(text, " ");
+}
+
+LogEntry& LogEntry::message(const std::string& message) {
+    mMsg = message;
+    return *this;
+}
+
+LogEntry& LogEntry::function(const std::string& function_name) {
+    mFunc = function_name;
+    return *this;
+}
+
+LogEntry& LogEntry::prettyFunction(const std::string& pretty_function) {
+    // __PRETTY_FUNCTION__ generally seems to be of the form:
+    //
+    //     qualifed::returnType qualified::function(args...)
+    //
+    // where the qualified forms include "(anonymous namespace)" in the
+    // "::"-delimited list and keywords like "virtual" (where applicable).
+    //
+    // Here we try to convert strings like:
+    //
+    //     virtual binder::Status android::net::NetdNativeService::isAlive(bool *)
+    //     netdutils::LogEntry android::netd::(anonymous namespace)::AAA::BBB::function()
+    //
+    // into just "NetdNativeService::isAlive" or "BBB::function". Note that
+    // without imposing convention, how to easily identify any namespace/class
+    // name boundary is not obvious.
+    const size_t endFuncName = pretty_function.rfind('(');
+    const size_t precedingSpace = pretty_function.rfind(' ', endFuncName);
+    size_t substrStart = (precedingSpace != std::string::npos) ? precedingSpace + 1 : 0;
+
+    const size_t beginFuncName = pretty_function.rfind("::", endFuncName);
+    if (beginFuncName != std::string::npos && substrStart < beginFuncName) {
+        const size_t previousNameBoundary = pretty_function.rfind("::", beginFuncName - 1);
+        if (previousNameBoundary < beginFuncName && substrStart < previousNameBoundary) {
+            substrStart = previousNameBoundary + 2;
+        } else {
+            substrStart = beginFuncName + 2;
+        }
+    }
+
+    mFunc = pretty_function.substr(substrStart, endFuncName - substrStart);
+    return *this;
+}
+
+LogEntry& LogEntry::arg(const std::string& val) {
+    mArgs.push_back(val.empty() ? "\"\"" : val);
+    return *this;
+}
+
+template <>
+LogEntry& LogEntry::arg<>(bool val) {
+    mArgs.push_back(val ? "true" : "false");
+    return *this;
+}
+
+LogEntry& LogEntry::arg(const std::vector<int32_t>& val) {
+    mArgs.push_back(StringPrintf("[%s]", Join(val, ", ").c_str()));
+    return *this;
+}
+
+LogEntry& LogEntry::arg(const std::vector<uint8_t>& val) {
+    mArgs.push_back('{' + toHex(makeSlice(val)) + '}');
+    return *this;
+}
+
+LogEntry& LogEntry::arg(const std::vector<std::string>& val) {
+    mArgs.push_back(StringPrintf("[%s]", Join(val, ", ").c_str()));
+    return *this;
+}
+
+LogEntry& LogEntry::returns(const std::string& rval) {
+    mReturns.push_back(rval);
+    return *this;
+}
+
+LogEntry& LogEntry::returns(bool rval) {
+    mReturns.push_back(rval ? "true" : "false");
+    return *this;
+}
+
+LogEntry& LogEntry::returns(const Status& status) {
+    mReturns.push_back(status.msg());
+    return *this;
+}
+
+LogEntry& LogEntry::withUid(uid_t uid) {
+    mUid = StringPrintf("(uid=%d)", uid);
+    return *this;
+}
+
+LogEntry& LogEntry::withAutomaticDuration() {
+    using ms = std::chrono::duration<float, std::ratio<1, 1000>>;
+
+    const std::chrono::steady_clock::time_point end = std::chrono::steady_clock::now();
+    std::stringstream duration;
+    duration << std::setprecision(1) << std::chrono::duration_cast<ms>(end - mStart).count()
+             << "ms";
+    mDuration = duration.str();
+    return *this;
+}
+
+LogEntry& LogEntry::withDuration(const std::string& duration) {
+    mDuration = duration;
+    return *this;
+}
+
+Log::~Log() {
+    // TODO: dump the last N entries to the android log for possible posterity.
+    info(LogEntry().function(__FUNCTION__));
+}
+
+void Log::forEachEntry(const std::function<void(const std::string&)>& perEntryFn) const {
+    // We make a (potentially expensive) copy of the log buffer (including
+    // all strings), in case the |perEntryFn| takes its sweet time.
+    std::deque<std::string> entries;
+    {
+        std::shared_lock<std::shared_mutex> guard(mLock);
+        entries.assign(mEntries.cbegin(), mEntries.cend());
+    }
+
+    for (const std::string& entry : entries) perEntryFn(entry);
+}
+
+void Log::record(Log::Level lvl, const std::string& entry) {
+    switch (lvl) {
+        case Level::LOG:
+            break;
+        case Level::INFO:
+            ALOG(LOG_INFO, mTag.c_str(), "%s", entry.c_str());
+            break;
+        case Level::WARN:
+            ALOG(LOG_WARN, mTag.c_str(), "%s", entry.c_str());
+            break;
+        case Level::ERROR:
+            ALOG(LOG_ERROR, mTag.c_str(), "%s", entry.c_str());
+            break;
+    }
+
+    std::lock_guard guard(mLock);
+    mEntries.push_back(makeTimestampedEntry(entry));
+    while (mEntries.size() > mMaxEntries) mEntries.pop_front();
+}
+
+}  // namespace netdutils
+}  // namespace android
--- a/staticlibs/netd/libnetdutils/LogTest.cpp
+++ b/staticlibs/netd/libnetdutils/LogTest.cpp
@@ -0,0 +1,143 @@
+/*
+ * 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 <gtest/gtest.h>
+
+#include "netdutils/Log.h"
+
+android::netdutils::LogEntry globalFunctionName() {
+    return android::netdutils::LogEntry().function(__FUNCTION__);
+}
+
+android::netdutils::LogEntry globalPrettyFunctionName() {
+    return android::netdutils::LogEntry().prettyFunction(__PRETTY_FUNCTION__);
+}
+
+namespace android {
+namespace netdutils {
+
+namespace {
+
+LogEntry functionName() {
+    return LogEntry().function(__FUNCTION__);
+}
+
+LogEntry prettyFunctionName() {
+    return LogEntry().prettyFunction(__PRETTY_FUNCTION__);
+}
+
+}  // namespace
+
+class AAA {
+  public:
+    AAA() = default;
+
+    LogEntry functionName() {
+        return LogEntry().function(__FUNCTION__);
+    }
+
+    LogEntry prettyFunctionName() {
+        return LogEntry().prettyFunction(__PRETTY_FUNCTION__);
+    }
+
+    class BBB {
+      public:
+        BBB() = default;
+
+        LogEntry functionName() {
+            return LogEntry().function(__FUNCTION__);
+        }
+
+        LogEntry prettyFunctionName() {
+            return LogEntry().prettyFunction(__PRETTY_FUNCTION__);
+        }
+    };
+};
+
+TEST(LogEntryTest, Empty) {
+    LogEntry empty;
+    EXPECT_EQ("", empty.toString());
+}
+
+TEST(LogEntryTest, GlobalFunction) {
+    EXPECT_EQ("globalFunctionName()", ::globalFunctionName().toString());
+}
+
+TEST(LogEntryTest, GlobalPrettyFunction) {
+    EXPECT_EQ("globalPrettyFunctionName()", ::globalPrettyFunctionName().toString());
+}
+
+TEST(LogEntryTest, UnnamedNamespaceFunction) {
+    const LogEntry entry = functionName();
+    EXPECT_EQ("functionName()", entry.toString());
+}
+
+TEST(LogEntryTest, UnnamedNamespacePrettyFunction) {
+    const LogEntry entry = prettyFunctionName();
+    EXPECT_EQ("prettyFunctionName()", entry.toString());
+}
+
+TEST(LogEntryTest, ClassFunction) {
+    const LogEntry entry = AAA().functionName();
+    EXPECT_EQ("functionName()", entry.toString());
+}
+
+TEST(LogEntryTest, ClassPrettyFunction) {
+    const LogEntry entry = AAA().prettyFunctionName();
+    EXPECT_EQ("AAA::prettyFunctionName()", entry.toString());
+}
+
+TEST(LogEntryTest, InnerClassFunction) {
+    const LogEntry entry = AAA::BBB().functionName();
+    EXPECT_EQ("functionName()", entry.toString());
+}
+
+TEST(LogEntryTest, InnerClassPrettyFunction) {
+    const LogEntry entry = AAA::BBB().prettyFunctionName();
+    EXPECT_EQ("BBB::prettyFunctionName()", entry.toString());
+}
+
+TEST(LogEntryTest, PrintChainedArguments) {
+    const LogEntry entry = LogEntry()
+            .function("testFunc")
+            .arg("hello")
+            .arg(42)
+            .arg(true);
+    EXPECT_EQ("testFunc(hello, 42, true)", entry.toString());
+}
+
+TEST(LogEntryTest, PrintIntegralTypes) {
+    const LogEntry entry = LogEntry()
+            .function("testFunc")
+            .arg('A')
+            .arg(100U)
+            .arg(-1000LL);
+    EXPECT_EQ("testFunc(65, 100, -1000)", entry.toString());
+}
+
+TEST(LogEntryTest, PrintHex) {
+    const std::vector<uint8_t> buf{0xDE, 0xAD, 0xBE, 0xEF};
+    const LogEntry entry = LogEntry().function("testFunc").arg(buf);
+    EXPECT_EQ("testFunc({deadbeef})", entry.toString());
+}
+
+TEST(LogEntryTest, PrintArgumentPack) {
+    const LogEntry entry = LogEntry().function("testFunc").args("hello", 42, false);
+    EXPECT_EQ("testFunc(hello, 42, false)", entry.toString());
+}
+
+}  // namespace netdutils
+}  // namespace android
--- a/staticlibs/netd/libnetdutils/MemBlockTest.cpp
+++ b/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
--- a/staticlibs/netd/libnetdutils/Netfilter.cpp
+++ b/staticlibs/netd/libnetdutils/Netfilter.cpp
@@ -0,0 +1,30 @@
+/*
+ * 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 <arpa/inet.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netlink.h>
+#include <ios>
+
+#include "netdutils/Netfilter.h"
+
+std::ostream& operator<<(std::ostream& os, const nfgenmsg& msg) {
+    return os << std::hex << "nfgenmsg["
+              << "family: 0x" << static_cast<int>(msg.nfgen_family) << ", version: 0x"
+              << static_cast<int>(msg.version) << ", res_id: 0x" << ntohs(msg.res_id) << "]"
+              << std::dec;
+}
--- a/staticlibs/netd/libnetdutils/Netlink.cpp
+++ b/staticlibs/netd/libnetdutils/Netlink.cpp
@@ -0,0 +1,78 @@
+/*
+ * 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 <ios>
+#include <linux/netlink.h>
+
+#include "netdutils/Math.h"
+#include "netdutils/Netlink.h"
+
+namespace android {
+namespace netdutils {
+
+void forEachNetlinkMessage(const Slice buf,
+                           const std::function<void(const nlmsghdr&, const Slice)>& onMsg) {
+    Slice tail = buf;
+    while (tail.size() >= sizeof(nlmsghdr)) {
+        nlmsghdr hdr = {};
+        extract(tail, hdr);
+        const auto len = std::max<size_t>(hdr.nlmsg_len, sizeof(hdr));
+        onMsg(hdr, drop(take(tail, len), sizeof(hdr)));
+        tail = drop(tail, align(len, 2));
+    }
+}
+
+void forEachNetlinkAttribute(const Slice buf,
+                             const std::function<void(const nlattr&, const Slice)>& onAttr) {
+    Slice tail = buf;
+    while (tail.size() >= sizeof(nlattr)) {
+        nlattr hdr = {};
+        extract(tail, hdr);
+        const auto len = std::max<size_t>(hdr.nla_len, sizeof(hdr));
+        onAttr(hdr, drop(take(tail, len), sizeof(hdr)));
+        tail = drop(tail, align(len, 2));
+    }
+}
+
+}  // namespace netdutils
+}  // namespace android
+
+bool operator==(const sockaddr_nl& lhs, const sockaddr_nl& rhs) {
+    return (lhs.nl_family == rhs.nl_family) && (lhs.nl_pid == rhs.nl_pid) &&
+           (lhs.nl_groups == rhs.nl_groups);
+}
+
+bool operator!=(const sockaddr_nl& lhs, const sockaddr_nl& rhs) {
+    return !(lhs == rhs);
+}
+
+std::ostream& operator<<(std::ostream& os, const nlmsghdr& hdr) {
+    return os << std::hex << "nlmsghdr["
+              << "len: 0x" << hdr.nlmsg_len << ", type: 0x" << hdr.nlmsg_type << ", flags: 0x"
+              << hdr.nlmsg_flags << ", seq: 0x" << hdr.nlmsg_seq << ", pid: 0x" << hdr.nlmsg_pid
+              << "]" << std::dec;
+}
+
+std::ostream& operator<<(std::ostream& os, const nlattr& attr) {
+    return os << std::hex << "nlattr["
+              << "len: 0x" << attr.nla_len << ", type: 0x" << attr.nla_type << "]" << std::dec;
+}
+
+std::ostream& operator<<(std::ostream& os, const sockaddr_nl& addr) {
+    return os << std::hex << "sockaddr_nl["
+              << "family: " << addr.nl_family << ", pid: " << addr.nl_pid
+              << ", groups: " << addr.nl_groups << "]" << std::dec;
+}
--- a/staticlibs/netd/libnetdutils/Slice.cpp
+++ b/staticlibs/netd/libnetdutils/Slice.cpp
@@ -0,0 +1,61 @@
+/*
+ * 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 <sstream>
+
+#include "netdutils/Slice.h"
+
+namespace android {
+namespace netdutils {
+namespace {
+
+// Convert one byte to a two character hexadecimal string
+const std::string toHex(uint8_t byte) {
+    const std::array<char, 16> kLookup = {
+        {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'}};
+    return {kLookup[byte >> 4], kLookup[byte & 0xf]};
+}
+
+}  // namespace
+
+std::string toString(const Slice s) {
+    return std::string(reinterpret_cast<char*>(s.base()), s.size());
+}
+
+std::string toHex(const Slice s, int wrap) {
+    Slice tail = s;
+    int count = 0;
+    std::stringstream ss;
+    while (!tail.empty()) {
+        uint8_t byte = 0;
+        extract(tail, byte);
+        ss << toHex(byte);
+        if ((++count % wrap) == 0) {
+            ss << "\n";
+        }
+        tail = drop(tail, 1);
+    }
+    return ss.str();
+}
+
+std::ostream& operator<<(std::ostream& os, const Slice& slice) {
+    return os << std::hex << "Slice[base: " << reinterpret_cast<void*>(slice.base())
+              << ", limit: " << reinterpret_cast<void*>(slice.limit()) << ", size: 0x"
+              << slice.size() << "]" << std::dec;
+}
+
+}  // namespace netdutils
+}  // namespace android
--- a/staticlibs/netd/libnetdutils/SliceTest.cpp
+++ b/staticlibs/netd/libnetdutils/SliceTest.cpp
@@ -0,0 +1,135 @@
+/*
+ * 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 <array>
+#include <cstdint>
+
+#include <gtest/gtest.h>
+
+#include "netdutils/Slice.h"
+#include "netdutils/Status.h"
+#include "netdutils/StatusOr.h"
+
+namespace android {
+namespace netdutils {
+
+class SliceTest : public testing::Test {
+  protected:
+    std::array<char, 256> mRaw = {};
+};
+
+TEST_F(SliceTest, smoke) {
+    Slice s1 = makeSlice(mRaw);
+    Slice s2 = makeSlice(mRaw);
+    auto p = split(s1, 14);
+    s2 = p.first; // avoid warn-unused error
+    std::stringstream ss;
+    ss << Slice();
+    EXPECT_EQ("Slice[base: 0x0, limit: 0x0, size: 0x0]", ss.str());
+    constexpr size_t kBytes = 14;
+    EXPECT_EQ(s1.base(), take(s1, kBytes).base());
+    EXPECT_EQ(kBytes, take(s1, kBytes).size());
+    EXPECT_EQ(s1.base() + kBytes, drop(s1, kBytes).base());
+    EXPECT_EQ(s1.size() - kBytes, drop(s1, kBytes).size());
+    double a = 0;
+    double b = 0;
+    int c = 0;
+    EXPECT_EQ(sizeof(a), extract(s1, a));
+    EXPECT_EQ(sizeof(a) + sizeof(b), extract(s1, a, b));
+    EXPECT_EQ(sizeof(a) + sizeof(b) + sizeof(c), extract(s1, a, b, c));
+}
+
+TEST_F(SliceTest, constructor) {
+    // Expect the following lines to compile
+    Slice s1 = makeSlice(mRaw);
+    Slice s2(s1);
+    Slice s3 = s2;
+    const Slice s4(s3);
+    const Slice s5 = s4;
+    s3 = s5;
+    Slice s6(mRaw.data(), mRaw.size());
+    Slice s7(mRaw.data(), mRaw.data() + mRaw.size());
+    struct {
+      int a;
+      double b;
+      float c;
+    } anon;
+    makeSlice(anon);
+    EXPECT_EQ(reinterpret_cast<uint8_t*>(mRaw.data()), s1.base());
+    EXPECT_EQ(reinterpret_cast<uint8_t*>(mRaw.data()) + mRaw.size(), s1.limit());
+    EXPECT_EQ(mRaw.size(), s1.size());
+    EXPECT_FALSE(mRaw.empty());
+    EXPECT_TRUE(Slice().empty());
+    EXPECT_TRUE(Slice(nullptr, static_cast<size_t>(0)).empty());
+    EXPECT_TRUE(Slice(nullptr, nullptr).empty());
+}
+
+TEST_F(SliceTest, extract) {
+    struct A {
+        int a, b;
+        bool operator==(const A& other) const { return a == other.a && b == other.b; }
+    };
+    struct B {
+        char str[12];
+        bool b;
+        int i;
+        bool operator==(const B& other) const {
+            return b == other.b && i == other.i && 0 == strncmp(str, other.str, 12);
+        }
+    };
+
+    A origA1 = {1, 2};
+    A origA2 = {3, 4};
+    B origB = {"hello world", true, 1234};
+
+    // Populate buffer for extracting.
+    Slice buffer = makeSlice(mRaw);
+    copy(buffer, makeSlice(origA1));
+    copy(drop(buffer, sizeof(origA1)), makeSlice(origB));
+    copy(drop(buffer, sizeof(origA1) + sizeof(origB)), makeSlice(origA2));
+
+    {
+        // Non-variadic extract
+        A a1{};
+        size_t len = extract(buffer, a1);
+        EXPECT_EQ(sizeof(A), len);
+        EXPECT_EQ(origA1, a1);
+    }
+
+    {
+        // Variadic extract, 2 destinations
+        A a1{};
+        B b{};
+        size_t len = extract(buffer, a1, b);
+        EXPECT_EQ(sizeof(A) + sizeof(B), len);
+        EXPECT_EQ(origA1, a1);
+        EXPECT_EQ(origB, b);
+    }
+
+    {
+        // Variadic extract, 3 destinations
+        A a1{}, a2{};
+        B b{};
+        size_t len = extract(buffer, a1, b, a2);
+        EXPECT_EQ(2 * sizeof(A) + sizeof(B), len);
+        EXPECT_EQ(origA1, a1);
+        EXPECT_EQ(origB, b);
+        EXPECT_EQ(origA2, a2);
+    }
+}
+
+}  // namespace netdutils
+}  // namespace android
--- a/staticlibs/netd/libnetdutils/Socket.cpp
+++ b/staticlibs/netd/libnetdutils/Socket.cpp
@@ -0,0 +1,35 @@
+/*
+ * 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 <arpa/inet.h>
+
+#include "netdutils/Slice.h"
+#include "netdutils/Socket.h"
+
+namespace android {
+namespace netdutils {
+
+StatusOr<std::string> toString(const in6_addr& addr) {
+    std::array<char, INET6_ADDRSTRLEN> out = {};
+    auto* rv = inet_ntop(AF_INET6, &addr, out.data(), out.size());
+    if (rv == nullptr) {
+        return statusFromErrno(errno, "inet_ntop() failed");
+    }
+    return std::string(out.data());
+}
+
+}  // namespace netdutils
+}  // namespace android
--- a/staticlibs/netd/libnetdutils/SocketOption.cpp
+++ b/staticlibs/netd/libnetdutils/SocketOption.cpp
@@ -0,0 +1,54 @@
+/*
+ * 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 "netdutils/SocketOption.h"
+
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <sys/socket.h>
+#include <utility>
+
+#include "netdutils/Syscalls.h"
+
+namespace android {
+namespace netdutils {
+
+Status enableSockopt(Fd sock, int level, int optname) {
+    auto& sys = sSyscalls.get();
+    const int on = 1;
+    return sys.setsockopt(sock, level, optname, &on, sizeof(on));
+}
+
+Status enableTcpKeepAlives(Fd sock, unsigned idleTime, unsigned numProbes, unsigned probeInterval) {
+    RETURN_IF_NOT_OK(enableSockopt(sock, SOL_SOCKET, SO_KEEPALIVE));
+
+    auto& sys = sSyscalls.get();
+    if (idleTime != 0) {
+        RETURN_IF_NOT_OK(sys.setsockopt(sock, SOL_TCP, TCP_KEEPIDLE, &idleTime, sizeof(idleTime)));
+    }
+    if (numProbes != 0) {
+        RETURN_IF_NOT_OK(sys.setsockopt(sock, SOL_TCP, TCP_KEEPCNT, &numProbes, sizeof(numProbes)));
+    }
+    if (probeInterval != 0) {
+        RETURN_IF_NOT_OK(sys.setsockopt(sock, SOL_TCP, TCP_KEEPINTVL, &probeInterval,
+                sizeof(probeInterval)));
+    }
+
+    return status::ok;
+}
+
+}  // namespace netdutils
+}  // namespace android
--- a/staticlibs/netd/libnetdutils/Status.cpp
+++ b/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
--- a/staticlibs/netd/libnetdutils/StatusTest.cpp
+++ b/staticlibs/netd/libnetdutils/StatusTest.cpp
@@ -0,0 +1,105 @@
+/*
+ * 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 "netdutils/StatusOr.h"
+
+#include <sstream>
+
+#include <gtest/gtest.h>
+
+namespace android {
+namespace netdutils {
+namespace {
+
+TEST(StatusTest, valueSemantics) {
+    // Default constructor
+    EXPECT_EQ(status::ok, Status());
+
+    // Copy constructor
+    Status status1(1);
+    Status status2(status1);  // NOLINT(performance-unnecessary-copy-initialization)
+    EXPECT_EQ(1, status2.code());
+
+    // Copy assignment
+    Status status3;
+    status3 = status2;
+    EXPECT_EQ(1, status3.code());
+
+    // Same with const objects
+    const Status status4(4);
+    const Status status5(status4);  // NOLINT(performance-unnecessary-copy-initialization)
+    Status status6;
+    status6 = status5;
+    EXPECT_EQ(4, status6.code());
+}
+
+TEST(StatusTest, errorMessages) {
+    Status s(42, "for tea too");
+    EXPECT_EQ(42, s.code());
+    EXPECT_FALSE(s.ok());
+    EXPECT_EQ(s.msg(), "for tea too");
+}
+
+TEST(StatusOrTest, moveSemantics) {
+    // Status objects should be cheaply movable.
+    EXPECT_TRUE(std::is_nothrow_move_constructible<Status>::value);
+    EXPECT_TRUE(std::is_nothrow_move_assignable<Status>::value);
+
+    // Should move from a temporary Status (twice)
+    Status s(Status(Status(42, "move me")));
+    EXPECT_EQ(42, s.code());
+    EXPECT_EQ(s.msg(), "move me");
+
+    Status s2(666, "EDAEMON");
+    EXPECT_NE(s, s2);
+    s = s2;  // Invokes the move-assignment operator.
+    EXPECT_EQ(666, s.code());
+    EXPECT_EQ(s.msg(), "EDAEMON");
+    EXPECT_EQ(s, s2);
+
+    // A moved-from Status can be re-used.
+    s2 = s;
+
+    // Now both objects are valid.
+    EXPECT_EQ(666, s.code());
+    EXPECT_EQ(s.msg(), "EDAEMON");
+    EXPECT_EQ(s, s2);
+}
+
+TEST(StatusTest, ignoredStatus) {
+    statusFromErrno(ENOTTY, "Not a typewriter, what did you expect?").ignoreError();
+}
+
+TEST(StatusOrTest, ostream) {
+    {
+      StatusOr<int> so(11);
+      std::stringstream ss;
+      ss << so;
+      // TODO: Fix StatusOr to optionally output "value:".
+      EXPECT_EQ("StatusOr[status: Status[code: 0, msg: \"\"]]", ss.str());
+    }
+    {
+      StatusOr<int> err(status::undefined);
+      std::stringstream ss;
+      ss << err;
+      EXPECT_EQ("StatusOr[status: Status[code: 2147483647, msg: \"undefined\"]]", ss.str());
+    }
+}
+
+}  // namespace
+}  // namespace netdutils
+}  // namespace android
--- a/staticlibs/netd/libnetdutils/Syscalls.cpp
+++ b/staticlibs/netd/libnetdutils/Syscalls.cpp
@@ -0,0 +1,265 @@
+/*
+ * 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/Syscalls.h"
+
+#include <atomic>
+#include <type_traits>
+#include <utility>
+
+namespace android {
+namespace netdutils {
+namespace {
+
+// Retry syscall fn as long as it returns -1 with errno == EINTR
+template <typename FnT, typename... Params>
+typename std::result_of<FnT(Params...)>::type syscallRetry(FnT fn, Params&&... params) {
+    auto rv = fn(std::forward<Params>(params)...);
+    while ((rv == -1) && (errno == EINTR)) {
+        rv = fn(std::forward<Params>(params)...);
+    }
+    return rv;
+}
+
+}  // namespace
+
+// Production implementation of Syscalls that forwards to libc syscalls.
+class RealSyscalls final : public Syscalls {
+  public:
+    ~RealSyscalls() override = default;
+
+    StatusOr<UniqueFd> open(const std::string& pathname, int flags, mode_t mode) const override {
+        UniqueFd fd(::open(pathname.c_str(), flags, mode));
+        if (!isWellFormed(fd)) {
+            return statusFromErrno(errno, "open(\"" + pathname + "\"...) failed");
+        }
+        return fd;
+    }
+
+    StatusOr<UniqueFd> socket(int domain, int type, int protocol) const override {
+        UniqueFd sock(::socket(domain, type, protocol));
+        if (!isWellFormed(sock)) {
+            return statusFromErrno(errno, "socket() failed");
+        }
+        return sock;
+    }
+
+    Status getsockname(Fd sock, sockaddr* addr, socklen_t* addrlen) const override {
+        auto rv = ::getsockname(sock.get(), addr, addrlen);
+        if (rv == -1) {
+            return statusFromErrno(errno, "getsockname() failed");
+        }
+        return status::ok;
+    }
+
+    Status getsockopt(Fd sock, int level, int optname, void* optval,
+                      socklen_t* optlen) const override {
+        auto rv = ::getsockopt(sock.get(), level, optname, optval, optlen);
+        if (rv == -1) {
+            return statusFromErrno(errno, "getsockopt() failed");
+        }
+        return status::ok;
+    }
+
+    Status setsockopt(Fd sock, int level, int optname, const void* optval,
+                      socklen_t optlen) const override {
+        auto rv = ::setsockopt(sock.get(), level, optname, optval, optlen);
+        if (rv == -1) {
+            return statusFromErrno(errno, "setsockopt() failed");
+        }
+        return status::ok;
+    }
+
+    Status bind(Fd sock, const sockaddr* addr, socklen_t addrlen) const override {
+        auto rv = ::bind(sock.get(), addr, addrlen);
+        if (rv == -1) {
+            return statusFromErrno(errno, "bind() failed");
+        }
+        return status::ok;
+    }
+
+    Status connect(Fd sock, const sockaddr* addr, socklen_t addrlen) const override {
+        auto rv = syscallRetry(::connect, sock.get(), addr, addrlen);
+        if (rv == -1) {
+            return statusFromErrno(errno, "connect() failed");
+        }
+        return status::ok;
+    }
+
+    StatusOr<ifreq> ioctl(Fd sock, unsigned long request, ifreq* ifr) const override {
+        auto rv = ::ioctl(sock.get(), request, ifr);
+        if (rv == -1) {
+            return statusFromErrno(errno, "ioctl() failed");
+        }
+        return *ifr;
+    }
+
+    StatusOr<UniqueFd> eventfd(unsigned int initval, int flags) const override {
+        UniqueFd fd(::eventfd(initval, flags));
+        if (!isWellFormed(fd)) {
+            return statusFromErrno(errno, "eventfd() failed");
+        }
+        return fd;
+    }
+
+    StatusOr<int> ppoll(pollfd* fds, nfds_t nfds, double timeout) const override {
+        timespec ts = {};
+        ts.tv_sec = timeout;
+        ts.tv_nsec = (timeout - ts.tv_sec) * 1e9;
+        auto rv = syscallRetry(::ppoll, fds, nfds, &ts, nullptr);
+        if (rv == -1) {
+            return statusFromErrno(errno, "ppoll() failed");
+        }
+        return rv;
+    }
+
+    StatusOr<size_t> writev(Fd fd, const std::vector<iovec>& iov) const override {
+        auto rv = syscallRetry(::writev, fd.get(), iov.data(), iov.size());
+        if (rv == -1) {
+            return statusFromErrno(errno, "writev() failed");
+        }
+        return rv;
+    }
+
+    StatusOr<size_t> write(Fd fd, const Slice buf) const override {
+        auto rv = syscallRetry(::write, fd.get(), buf.base(), buf.size());
+        if (rv == -1) {
+            return statusFromErrno(errno, "write() failed");
+        }
+        return static_cast<size_t>(rv);
+    }
+
+    StatusOr<Slice> read(Fd fd, const Slice buf) const override {
+        auto rv = syscallRetry(::read, fd.get(), buf.base(), buf.size());
+        if (rv == -1) {
+            return statusFromErrno(errno, "read() failed");
+        }
+        return Slice(buf.base(), rv);
+    }
+
+    StatusOr<size_t> sendto(Fd sock, const Slice buf, int flags, const sockaddr* dst,
+                            socklen_t dstlen) const override {
+        auto rv = syscallRetry(::sendto, sock.get(), buf.base(), buf.size(), flags, dst, dstlen);
+        if (rv == -1) {
+            return statusFromErrno(errno, "sendto() failed");
+        }
+        return static_cast<size_t>(rv);
+    }
+
+    StatusOr<Slice> recvfrom(Fd sock, const Slice dst, int flags, sockaddr* src,
+                             socklen_t* srclen) const override {
+        auto rv = syscallRetry(::recvfrom, sock.get(), dst.base(), dst.size(), flags, src, srclen);
+        if (rv == -1) {
+            return statusFromErrno(errno, "recvfrom() failed");
+        }
+        if (rv == 0) {
+            return status::eof;
+        }
+        return take(dst, rv);
+    }
+
+    Status shutdown(Fd fd, int how) const override {
+        auto rv = ::shutdown(fd.get(), how);
+        if (rv == -1) {
+            return statusFromErrno(errno, "shutdown() failed");
+        }
+        return status::ok;
+    }
+
+    Status close(Fd fd) const override {
+        auto rv = ::close(fd.get());
+        if (rv == -1) {
+            return statusFromErrno(errno, "close() failed");
+        }
+        return status::ok;
+    }
+
+    StatusOr<UniqueFile> fopen(const std::string& path, const std::string& mode) const override {
+        UniqueFile file(::fopen(path.c_str(), mode.c_str()));
+        if (file == nullptr) {
+            return statusFromErrno(errno, "fopen(\"" + path + "\", \"" + mode + "\") failed");
+        }
+        return file;
+    }
+
+    StatusOr<pid_t> fork() const override {
+        pid_t rv = ::fork();
+        if (rv == -1) {
+            return statusFromErrno(errno, "fork() failed");
+        }
+        return rv;
+    }
+
+    StatusOr<int> vfprintf(FILE* file, const char* format, va_list ap) const override {
+        auto rv = ::vfprintf(file, format, ap);
+        if (rv == -1) {
+            return statusFromErrno(errno, "vfprintf() failed");
+        }
+        return rv;
+    }
+
+    StatusOr<int> vfscanf(FILE* file, const char* format, va_list ap) const override {
+        auto rv = ::vfscanf(file, format, ap);
+        if (rv == -1) {
+            return statusFromErrno(errno, "vfscanf() failed");
+        }
+        return rv;
+    }
+
+    Status fclose(FILE* file) const override {
+        auto rv = ::fclose(file);
+        if (rv == -1) {
+            return statusFromErrno(errno, "fclose() failed");
+        }
+        return status::ok;
+    }
+};
+
+SyscallsHolder::~SyscallsHolder() {
+    delete &get();
+}
+
+Syscalls& SyscallsHolder::get() {
+    while (true) {
+        // memory_order_relaxed gives the compiler and hardware more
+        // freedom. If we get a stale value (this should only happen
+        // early in the execution of a program) the exchange code below
+        // will loop until we get the most current value.
+        auto* syscalls = mSyscalls.load(std::memory_order_relaxed);
+        // Common case returns existing syscalls
+        if (syscalls) {
+            return *syscalls;
+        }
+
+        // This code will execute on first get()
+        std::unique_ptr<Syscalls> tmp(new RealSyscalls());
+        Syscalls* expected = nullptr;
+        bool success = mSyscalls.compare_exchange_strong(expected, tmp.get());
+        if (success) {
+            // Ownership was transferred to mSyscalls already, must release()
+            return *tmp.release();
+        }
+    }
+}
+
+Syscalls& SyscallsHolder::swap(Syscalls& syscalls) {
+    return *mSyscalls.exchange(&syscalls);
+}
+
+SyscallsHolder sSyscalls;
+
+}  // namespace netdutils
+}  // namespace android
--- a/staticlibs/netd/libnetdutils/SyscallsTest.cpp
+++ b/staticlibs/netd/libnetdutils/SyscallsTest.cpp
@@ -0,0 +1,202 @@
+/*
+ * 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 <array>
+#include <cstdint>
+#include <memory>
+
+#include <gtest/gtest.h>
+
+#include "netdutils/Handle.h"
+#include "netdutils/Math.h"
+#include "netdutils/MockSyscalls.h"
+#include "netdutils/Netfilter.h"
+#include "netdutils/Netlink.h"
+#include "netdutils/Slice.h"
+#include "netdutils/Status.h"
+#include "netdutils/StatusOr.h"
+#include "netdutils/Syscalls.h"
+
+using testing::_;
+using testing::ByMove;
+using testing::Invoke;
+using testing::Return;
+using testing::StrictMock;
+
+namespace android {
+namespace netdutils {
+
+class SyscallsTest : public testing::Test {
+  protected:
+    StrictMock<ScopedMockSyscalls> mSyscalls;
+};
+
+TEST(syscalls, scopedMock) {
+    auto& old = sSyscalls.get();
+    {
+        StrictMock<ScopedMockSyscalls> s;
+        EXPECT_EQ(&s, &sSyscalls.get());
+    }
+    EXPECT_EQ(&old, &sSyscalls.get());
+}
+
+TEST_F(SyscallsTest, open) {
+    const char kPath[] = "/test/path/please/ignore";
+    constexpr Fd kFd(40);
+    constexpr int kFlags = 883;
+    constexpr mode_t kMode = 37373;
+    const auto& sys = sSyscalls.get();
+    EXPECT_CALL(mSyscalls, open(kPath, kFlags, kMode)).WillOnce(Return(ByMove(UniqueFd(kFd))));
+    EXPECT_CALL(mSyscalls, close(kFd)).WillOnce(Return(status::ok));
+    auto result = sys.open(kPath, kFlags, kMode);
+    EXPECT_EQ(status::ok, result.status());
+    EXPECT_EQ(kFd, result.value());
+}
+
+TEST_F(SyscallsTest, getsockname) {
+    constexpr Fd kFd(40);
+    sockaddr_nl expected = {};
+    auto& sys = sSyscalls.get();
+
+    // Success
+    EXPECT_CALL(mSyscalls, getsockname(kFd, _, _))
+        .WillOnce(Invoke([expected](Fd, sockaddr* addr, socklen_t* addrlen) {
+            memcpy(addr, &expected, sizeof(expected));
+            EXPECT_EQ(*addrlen, static_cast<socklen_t>(sizeof(expected)));
+            return status::ok;
+        }));
+    const auto result = sys.getsockname<sockaddr_nl>(kFd);
+    EXPECT_TRUE(isOk(result));
+    EXPECT_EQ(expected, result.value());
+
+    // Failure
+    const Status kError = statusFromErrno(EINVAL, "test");
+    EXPECT_CALL(mSyscalls, getsockname(kFd, _, _)).WillOnce(Return(kError));
+    EXPECT_EQ(kError, sys.getsockname<sockaddr_nl>(kFd).status());
+}
+
+TEST_F(SyscallsTest, setsockopt) {
+    constexpr Fd kFd(40);
+    constexpr int kLevel = 50;
+    constexpr int kOptname = 70;
+    sockaddr_nl expected = {};
+    auto& sys = sSyscalls.get();
+
+    // Success
+    EXPECT_CALL(mSyscalls, setsockopt(kFd, kLevel, kOptname, &expected, sizeof(expected)))
+        .WillOnce(Return(status::ok));
+    EXPECT_EQ(status::ok, sys.setsockopt(kFd, kLevel, kOptname, expected));
+
+    // Failure
+    const Status kError = statusFromErrno(EINVAL, "test");
+    EXPECT_CALL(mSyscalls, setsockopt(kFd, kLevel, kOptname, &expected, sizeof(expected)))
+        .WillOnce(Return(kError));
+    EXPECT_EQ(kError, sys.setsockopt(kFd, kLevel, kOptname, expected));
+}
+
+TEST_F(SyscallsTest, getsockopt) {
+    constexpr Fd kFd(40);
+    constexpr int kLevel = 50;
+    constexpr int kOptname = 70;
+    sockaddr_nl expected = {};
+    socklen_t optLen = 0;
+    auto& sys = sSyscalls.get();
+
+    // Success
+    EXPECT_CALL(mSyscalls, getsockopt(kFd, kLevel, kOptname, &expected, &optLen))
+        .WillOnce(Return(status::ok));
+    EXPECT_EQ(status::ok, sys.getsockopt(kFd, kLevel, kOptname, &expected, &optLen));
+
+    // Failure
+    const Status kError = statusFromErrno(EINVAL, "test");
+    EXPECT_CALL(mSyscalls, getsockopt(kFd, kLevel, kOptname, &expected, &optLen))
+        .WillOnce(Return(kError));
+    EXPECT_EQ(kError, sys.getsockopt(kFd, kLevel, kOptname, &expected, &optLen));
+}
+
+TEST_F(SyscallsTest, bind) {
+    constexpr Fd kFd(40);
+    sockaddr_nl expected = {};
+    auto& sys = sSyscalls.get();
+
+    // Success
+    EXPECT_CALL(mSyscalls, bind(kFd, asSockaddrPtr(&expected), sizeof(expected)))
+        .WillOnce(Return(status::ok));
+    EXPECT_EQ(status::ok, sys.bind(kFd, expected));
+
+    // Failure
+    const Status kError = statusFromErrno(EINVAL, "test");
+    EXPECT_CALL(mSyscalls, bind(kFd, asSockaddrPtr(&expected), sizeof(expected)))
+        .WillOnce(Return(kError));
+    EXPECT_EQ(kError, sys.bind(kFd, expected));
+}
+
+TEST_F(SyscallsTest, connect) {
+    constexpr Fd kFd(40);
+    sockaddr_nl expected = {};
+    auto& sys = sSyscalls.get();
+
+    // Success
+    EXPECT_CALL(mSyscalls, connect(kFd, asSockaddrPtr(&expected), sizeof(expected)))
+        .WillOnce(Return(status::ok));
+    EXPECT_EQ(status::ok, sys.connect(kFd, expected));
+
+    // Failure
+    const Status kError = statusFromErrno(EINVAL, "test");
+    EXPECT_CALL(mSyscalls, connect(kFd, asSockaddrPtr(&expected), sizeof(expected)))
+        .WillOnce(Return(kError));
+    EXPECT_EQ(kError, sys.connect(kFd, expected));
+}
+
+TEST_F(SyscallsTest, sendto) {
+    constexpr Fd kFd(40);
+    constexpr int kFlags = 0;
+    std::array<char, 10> payload;
+    const auto slice = makeSlice(payload);
+    sockaddr_nl expected = {};
+    auto& sys = sSyscalls.get();
+
+    // Success
+    EXPECT_CALL(mSyscalls, sendto(kFd, slice, kFlags, asSockaddrPtr(&expected), sizeof(expected)))
+        .WillOnce(Return(slice.size()));
+    EXPECT_EQ(status::ok, sys.sendto(kFd, slice, kFlags, expected));
+}
+
+TEST_F(SyscallsTest, recvfrom) {
+    constexpr Fd kFd(40);
+    constexpr int kFlags = 0;
+    std::array<char, 10> payload;
+    const auto dst = makeSlice(payload);
+    const auto used = take(dst, 8);
+    sockaddr_nl expected = {};
+    auto& sys = sSyscalls.get();
+
+    // Success
+    EXPECT_CALL(mSyscalls, recvfrom(kFd, dst, kFlags, _, _))
+            .WillOnce(Invoke(
+                    [expected, used](Fd, const Slice, int, sockaddr* src, socklen_t* srclen) {
+                        *srclen = sizeof(expected);
+                        memcpy(src, &expected, *srclen);
+                        return used;
+                    }));
+    auto result = sys.recvfrom<sockaddr_nl>(kFd, dst, kFlags);
+    EXPECT_EQ(status::ok, result.status());
+    EXPECT_EQ(used, result.value().first);
+    EXPECT_EQ(expected, result.value().second);
+}
+
+}  // namespace netdutils
+}  // namespace android
--- a/staticlibs/netd/libnetdutils/ThreadUtilTest.cpp
+++ b/staticlibs/netd/libnetdutils/ThreadUtilTest.cpp
@@ -0,0 +1,122 @@
+/*
+ * 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.
+ */
+
+#include <string>
+
+#include <android-base/expected.h>
+#include <gtest/gtest.h>
+#include <netdutils/ThreadUtil.h>
+
+namespace android::netdutils {
+
+namespace {
+
+android::base::expected<std::string, int> getThreadName() {
+    char name[16] = {};
+    if (const int ret = pthread_getname_np(pthread_self(), name, sizeof(name)); ret != 0) {
+        return android::base::unexpected(ret);
+    }
+    return std::string(name);
+}
+
+class NoopRun {
+  public:
+    explicit NoopRun(const std::string& name = "") : mName(name) { instanceNum++; }
+
+    // Destructor happens in the thread.
+    ~NoopRun() {
+        if (checkName) {
+            auto expected = getThreadName();
+            EXPECT_TRUE(expected.has_value());
+            EXPECT_EQ(mExpectedName, expected.value());
+        }
+        instanceNum--;
+    }
+
+    void run() {}
+
+    std::string threadName() { return mName; }
+
+    // Set the expected thread name which will be used to check if it matches the actual thread
+    // name which is returned from the system call. The check will happen in the destructor.
+    void setExpectedName(const std::string& expectedName) {
+        checkName = true;
+        mExpectedName = expectedName;
+    }
+
+    static bool waitForAllReleased(int timeoutMs) {
+        constexpr int intervalMs = 20;
+        int limit = timeoutMs / intervalMs;
+        for (int i = 1; i < limit; i++) {
+            if (instanceNum == 0) {
+                return true;
+            }
+            usleep(intervalMs * 1000);
+        }
+        return false;
+    }
+
+    // To track how many instances are alive.
+    static std::atomic<int> instanceNum;
+
+  private:
+    std::string mName;
+    std::string mExpectedName;
+    bool checkName = false;
+};
+
+std::atomic<int> NoopRun::instanceNum;
+
+}  // namespace
+
+TEST(ThreadUtilTest, objectReleased) {
+    NoopRun::instanceNum = 0;
+    NoopRun* obj = new NoopRun();
+    EXPECT_EQ(1, NoopRun::instanceNum);
+    threadLaunch(obj);
+
+    // Wait for the object released along with the thread exited.
+    EXPECT_TRUE(NoopRun::waitForAllReleased(1000));
+    EXPECT_EQ(0, NoopRun::instanceNum);
+}
+
+TEST(ThreadUtilTest, SetThreadName) {
+    NoopRun::instanceNum = 0;
+
+    // Test thread name empty.
+    NoopRun* obj1 = new NoopRun();
+    obj1->setExpectedName("");
+
+    // Test normal case.
+    NoopRun* obj2 = new NoopRun("TestName");
+    obj2->setExpectedName("TestName");
+
+    // Test thread name too long.
+    std::string name("TestNameTooooLong");
+    NoopRun* obj3 = new NoopRun(name);
+    obj3->setExpectedName(name.substr(0, 15));
+
+    // Thread names are examined in their destructors.
+    EXPECT_EQ(3, NoopRun::instanceNum);
+    threadLaunch(obj1);
+    threadLaunch(obj2);
+    threadLaunch(obj3);
+
+    EXPECT_TRUE(NoopRun::waitForAllReleased(1000));
+    EXPECT_EQ(0, NoopRun::instanceNum);
+}
+
+}  // namespace android::netdutils
--- a/staticlibs/netd/libnetdutils/UniqueFd.cpp
+++ b/staticlibs/netd/libnetdutils/UniqueFd.cpp
@@ -0,0 +1,38 @@
+/*
+ * 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 <algorithm>
+
+#include "netdutils/UniqueFd.h"
+#include "netdutils/Syscalls.h"
+
+namespace android {
+namespace netdutils {
+
+void UniqueFd::reset(Fd fd) {
+    auto& sys = sSyscalls.get();
+    std::swap(fd, mFd);
+    if (isWellFormed(fd)) {
+        expectOk(sys.close(fd));
+    }
+}
+
+std::ostream& operator<<(std::ostream& os, const UniqueFd& fd) {
+    return os << "UniqueFd[" << static_cast<Fd>(fd) << "]";
+}
+
+}  // namespace netdutils
+}  // namespace android
--- a/staticlibs/netd/libnetdutils/UniqueFile.cpp
+++ b/staticlibs/netd/libnetdutils/UniqueFile.cpp
@@ -0,0 +1,31 @@
+/*
+ * 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 <algorithm>
+
+#include "netdutils/Syscalls.h"
+#include "netdutils/UniqueFile.h"
+
+namespace android {
+namespace netdutils {
+
+void UniqueFileDtor::operator()(FILE* file) const {
+    const auto& sys = sSyscalls.get();
+    sys.fclose(file).ignoreError();
+}
+
+}  // namespace netdutils
+}  // namespace android
--- a/staticlibs/netd/libnetdutils/include/netdutils/BackoffSequence.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/BackoffSequence.h
@@ -0,0 +1,153 @@
+/*
+ * 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.
+ */
+
+#ifndef NETDUTILS_BACKOFFSEQUENCE_H
+#define NETDUTILS_BACKOFFSEQUENCE_H
+
+#include <stdint.h>
+#include <algorithm>
+#include <chrono>
+#include <limits>
+
+namespace android {
+namespace netdutils {
+
+// Encapsulate some RFC 3315 section 14 -style backoff mechanics.
+//
+//     https://tools.ietf.org/html/rfc3315#section-14
+template<typename time_type = std::chrono::seconds, typename counter_type = uint32_t>
+class BackoffSequence {
+  public:
+    struct Parameters {
+        time_type initialRetransTime{TIME_UNITY};
+        counter_type maxRetransCount{0U};
+        time_type maxRetransTime{TIME_ZERO};
+        time_type maxRetransDuration{TIME_ZERO};
+        time_type endOfSequenceIndicator{TIME_ZERO};
+    };
+
+    BackoffSequence() : BackoffSequence(Parameters{}) {}
+    BackoffSequence(const BackoffSequence &) = default;
+    BackoffSequence(BackoffSequence &&) = default;
+    BackoffSequence& operator=(const BackoffSequence &) = default;
+    BackoffSequence& operator=(BackoffSequence &&) = default;
+
+    bool hasNextTimeout() const noexcept {
+        return !maxRetransCountExceed() && !maxRetransDurationExceeded();
+    }
+
+    // Returns 0 when the sequence is exhausted.
+    time_type getNextTimeout() {
+        if (!hasNextTimeout()) return getEndOfSequenceIndicator();
+
+        mRetransTime = getNextTimeoutAfter(mRetransTime);
+
+        mRetransCount++;
+        mTotalRetransDuration += mRetransTime;
+        return mRetransTime;
+    }
+
+    time_type getEndOfSequenceIndicator() const noexcept {
+        return mParams.endOfSequenceIndicator;
+    }
+
+    class Builder {
+      public:
+        Builder() {}
+
+        constexpr Builder& withInitialRetransmissionTime(time_type irt) {
+            mParams.initialRetransTime = irt;
+            return *this;
+        }
+        constexpr Builder& withMaximumRetransmissionCount(counter_type mrc) {
+            mParams.maxRetransCount = mrc;
+            return *this;
+        }
+        constexpr Builder& withMaximumRetransmissionTime(time_type mrt) {
+            mParams.maxRetransTime = mrt;
+            return *this;
+        }
+        constexpr Builder& withMaximumRetransmissionDuration(time_type mrd) {
+            mParams.maxRetransDuration = mrd;
+            return *this;
+        }
+        constexpr Builder& withEndOfSequenceIndicator(time_type eos) {
+            mParams.endOfSequenceIndicator = eos;
+            return *this;
+        }
+
+        constexpr BackoffSequence build() const {
+            return BackoffSequence(mParams);
+        }
+
+      private:
+        Parameters mParams;
+    };
+
+  private:
+    static constexpr int PER_ITERATION_SCALING_FACTOR = 2;
+    static constexpr time_type TIME_ZERO = time_type();
+    static constexpr time_type TIME_UNITY = time_type(1);
+
+    constexpr BackoffSequence(const struct Parameters &params)
+            : mParams(params),
+              mRetransCount(0),
+              mRetransTime(TIME_ZERO),
+              mTotalRetransDuration(TIME_ZERO) {}
+
+    constexpr bool maxRetransCountExceed() const {
+        return (mParams.maxRetransCount > 0) && (mRetransCount >= mParams.maxRetransCount);
+    }
+
+    constexpr bool maxRetransDurationExceeded() const {
+        return (mParams.maxRetransDuration > TIME_ZERO) &&
+               (mTotalRetransDuration >= mParams.maxRetransDuration);
+    }
+
+    time_type getNextTimeoutAfter(time_type lastTimeout) const {
+        // TODO: Support proper random jitter. Also, consider supporting some
+        // per-iteration scaling factor other than doubling.
+        time_type nextTimeout = (lastTimeout > TIME_ZERO)
+                ? PER_ITERATION_SCALING_FACTOR * lastTimeout
+                : mParams.initialRetransTime;
+
+        // Check if overflow occurred.
+        if (nextTimeout < lastTimeout) {
+            nextTimeout = std::numeric_limits<time_type>::max();
+        }
+
+        // Cap to maximum allowed, if necessary.
+        if (mParams.maxRetransTime > TIME_ZERO) {
+            nextTimeout = std::min(nextTimeout, mParams.maxRetransTime);
+        }
+
+        // Don't overflow the maximum total duration.
+        if (mParams.maxRetransDuration > TIME_ZERO) {
+            nextTimeout = std::min(nextTimeout, mParams.maxRetransDuration - lastTimeout);
+        }
+        return nextTimeout;
+    }
+
+    const Parameters mParams;
+    counter_type mRetransCount;
+    time_type mRetransTime;
+    time_type mTotalRetransDuration;
+};
+
+}  // namespace netdutils
+}  // namespace android
+
+#endif /* NETDUTILS_BACKOFFSEQUENCE_H */
--- a/staticlibs/netd/libnetdutils/include/netdutils/DumpWriter.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/DumpWriter.h
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+#ifndef NETDUTILS_DUMPWRITER_H_
+#define NETDUTILS_DUMPWRITER_H_
+
+#include <string>
+
+namespace android {
+namespace netdutils {
+
+class DumpWriter {
+  public:
+    DumpWriter(int fd);
+
+    void incIndent();
+    void decIndent();
+
+    void println(const std::string& line);
+    template <size_t n>
+    void println(const char line[n]) {
+        println(std::string(line));
+    }
+    // Hint to the compiler that it should apply printf validation of
+    // arguments (beginning at position 3) of the format (specified in
+    // position 2). Note that position 1 is the implicit "this" argument.
+    void println(const char* fmt, ...) __attribute__((__format__(__printf__, 2, 3)));
+    void blankline() { println(""); }
+
+  private:
+    uint8_t mIndentLevel;
+    int mFd;
+};
+
+class ScopedIndent {
+  public:
+    ScopedIndent() = delete;
+    ScopedIndent(const ScopedIndent&) = delete;
+    ScopedIndent(ScopedIndent&&) = delete;
+    explicit ScopedIndent(DumpWriter& dw) : mDw(dw) { mDw.incIndent(); }
+    ~ScopedIndent() { mDw.decIndent(); }
+    ScopedIndent& operator=(const ScopedIndent&) = delete;
+    ScopedIndent& operator=(ScopedIndent&&) = delete;
+
+    // TODO: consider additional {inc,dec}Indent methods and a counter that
+    // can be used to unwind all pending increments on exit.
+
+  private:
+    DumpWriter& mDw;
+};
+
+}  // namespace netdutils
+}  // namespace android
+
+#endif  // NETDUTILS_DUMPWRITER_H_
--- a/staticlibs/netd/libnetdutils/include/netdutils/Fd.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/Fd.h
@@ -0,0 +1,54 @@
+/*
+ * 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.
+ */
+
+#ifndef NETUTILS_FD_H
+#define NETUTILS_FD_H
+
+#include <ostream>
+
+#include "netdutils/Status.h"
+
+namespace android {
+namespace netdutils {
+
+// Strongly typed wrapper for file descriptors with value semantics.
+// This class should typically hold unowned file descriptors.
+class Fd {
+  public:
+    constexpr Fd() = default;
+
+    constexpr Fd(int fd) : mFd(fd) {}
+
+    int get() const { return mFd; }
+
+    bool operator==(const Fd& other) const { return get() == other.get(); }
+    bool operator!=(const Fd& other) const { return get() != other.get(); }
+
+  private:
+    int mFd = -1;
+};
+
+// Return true if fd appears valid (non-negative)
+inline bool isWellFormed(const Fd fd) {
+    return fd.get() >= 0;
+}
+
+std::ostream& operator<<(std::ostream& os, const Fd& fd);
+
+}  // namespace netdutils
+}  // namespace android
+
+#endif /* NETUTILS_FD_H */
--- a/staticlibs/netd/libnetdutils/include/netdutils/Handle.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/Handle.h
@@ -0,0 +1,74 @@
+/*
+ * 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.
+ */
+
+#ifndef NETUTILS_HANDLE_H
+#define NETUTILS_HANDLE_H
+
+#include <ostream>
+
+namespace android {
+namespace netdutils {
+
+// Opaque, strongly typed wrapper for integer-like handles.
+// Explicitly avoids implementing arithmetic operations.
+//
+// This class is intended to avoid common errors when reordering
+// arguments to functions, typos and other cases where plain integer
+// types would silently cover up the mistake.
+//
+// usage:
+// DEFINE_HANDLE(ProductId, uint64_t);
+// DEFINE_HANDLE(ThumbnailHash, uint64_t);
+// void foo(ProductId p, ThumbnailHash th) {...}
+//
+// void test() {
+//     ProductId p(88);
+//     ThumbnailHash th1(100), th2(200);
+//
+//     foo(p, th1);        <- ok!
+//     foo(th1, p);        <- disallowed!
+//     th1 += 10;          <- disallowed!
+//     p = th2;            <- disallowed!
+//     assert(th1 != th2); <- ok!
+// }
+template <typename T, typename TagT>
+class Handle {
+  public:
+    constexpr Handle() = default;
+    constexpr Handle(const T& value) : mValue(value) {}
+
+    const T get() const { return mValue; }
+
+    bool operator==(const Handle& that) const { return get() == that.get(); }
+    bool operator!=(const Handle& that) const { return get() != that.get(); }
+
+  private:
+    T mValue;
+};
+
+#define DEFINE_HANDLE(name, type) \
+    struct _##name##Tag {};       \
+    using name = ::android::netdutils::Handle<type, _##name##Tag>;
+
+template <typename T, typename TagT>
+inline std::ostream& operator<<(std::ostream& os, const Handle<T, TagT>& handle) {
+    return os << handle.get();
+}
+
+}  // namespace netdutils
+}  // namespace android
+
+#endif /* NETUTILS_HANDLE_H */
--- a/staticlibs/netd/libnetdutils/include/netdutils/InternetAddresses.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/InternetAddresses.h
@@ -0,0 +1,325 @@
+/*
+ * 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.
+ */
+
+#pragma once
+
+#include <netdb.h>
+#include <netinet/in.h>
+#include <stdint.h>
+#include <cstring>
+#include <limits>
+#include <string>
+
+#include "netdutils/NetworkConstants.h"
+
+namespace android {
+namespace netdutils {
+
+namespace internal_ {
+
+// A structure to hold data for dealing with Internet addresses (IPAddress) and
+// related types such as IPSockAddr and IPPrefix.
+struct compact_ipdata {
+    uint8_t family{AF_UNSPEC};
+    uint8_t cidrlen{0U};  // written and read in host-byte order
+    in_port_t port{0U};   // written and read in host-byte order
+    uint32_t scope_id{0U};
+    union {
+        in_addr v4;
+        in6_addr v6;
+    } ip{.v6 = IN6ADDR_ANY_INIT};  // written and read in network-byte order
+
+    // Classes that use compact_ipdata and this method should be sure to clear
+    // (i.e. zero or make uniform) any fields not relevant to the class.
+    friend bool operator==(const compact_ipdata& a, const compact_ipdata& b) {
+        if ((a.family != b.family) || (a.cidrlen != b.cidrlen) || (a.port != b.port) ||
+            (a.scope_id != b.scope_id)) {
+            return false;
+        }
+        switch (a.family) {
+            case AF_UNSPEC:
+                // After the above checks, two AF_UNSPEC objects can be
+                // considered equal, for convenience.
+                return true;
+            case AF_INET: {
+                const in_addr v4a = a.ip.v4;
+                const in_addr v4b = b.ip.v4;
+                return (v4a.s_addr == v4b.s_addr);
+            }
+            case AF_INET6: {
+                const in6_addr v6a = a.ip.v6;
+                const in6_addr v6b = b.ip.v6;
+                return IN6_ARE_ADDR_EQUAL(&v6a, &v6b);
+            }
+        }
+        return false;
+    }
+
+    // Classes that use compact_ipdata and this method should be sure to clear
+    // (i.e. zero or make uniform) any fields not relevant to the class.
+    friend bool operator!=(const compact_ipdata& a, const compact_ipdata& b) { return !(a == b); }
+
+    // Classes that use compact_ipdata and this method should be sure to clear
+    // (i.e. zero or make uniform) any fields not relevant to the class.
+    friend bool operator<(const compact_ipdata& a, const compact_ipdata& b) {
+        if (a.family != b.family) return (a.family < b.family);
+        switch (a.family) {
+            case AF_INET: {
+                const in_addr v4a = a.ip.v4;
+                const in_addr v4b = b.ip.v4;
+                if (v4a.s_addr != v4b.s_addr) return (ntohl(v4a.s_addr) < ntohl(v4b.s_addr));
+                break;
+            }
+            case AF_INET6: {
+                const in6_addr v6a = a.ip.v6;
+                const in6_addr v6b = b.ip.v6;
+                const int cmp = std::memcmp(v6a.s6_addr, v6b.s6_addr, IPV6_ADDR_LEN);
+                if (cmp != 0) return cmp < 0;
+                break;
+            }
+        }
+        if (a.cidrlen != b.cidrlen) return (a.cidrlen < b.cidrlen);
+        if (a.port != b.port) return (a.port < b.port);
+        return (a.scope_id < b.scope_id);
+    }
+};
+
+static_assert(AF_UNSPEC <= std::numeric_limits<uint8_t>::max(), "AF_UNSPEC value too large");
+static_assert(AF_INET <= std::numeric_limits<uint8_t>::max(), "AF_INET value too large");
+static_assert(AF_INET6 <= std::numeric_limits<uint8_t>::max(), "AF_INET6 value too large");
+static_assert(sizeof(compact_ipdata) == 24U, "compact_ipdata unexpectedly large");
+
+}  // namespace internal_
+
+struct AddrinfoDeleter {
+    void operator()(struct addrinfo* p) const {
+        if (p != nullptr) {
+            freeaddrinfo(p);
+        }
+    }
+};
+
+typedef std::unique_ptr<struct addrinfo, struct AddrinfoDeleter> ScopedAddrinfo;
+
+inline bool usesScopedIds(const in6_addr& ipv6) {
+    return (IN6_IS_ADDR_LINKLOCAL(&ipv6) || IN6_IS_ADDR_MC_LINKLOCAL(&ipv6));
+}
+
+class IPPrefix;
+class IPSockAddr;
+
+class IPAddress {
+  public:
+    static bool forString(const std::string& repr, IPAddress* ip);
+    static IPAddress forString(const std::string& repr) {
+        IPAddress ip;
+        if (!forString(repr, &ip)) return IPAddress();
+        return ip;
+    }
+
+    IPAddress() = default;
+    IPAddress(const IPAddress&) = default;
+    IPAddress(IPAddress&&) = default;
+
+    explicit IPAddress(const in_addr& ipv4)
+        : mData({AF_INET, IPV4_ADDR_BITS, 0U, 0U, {.v4 = ipv4}}) {}
+    explicit IPAddress(const in6_addr& ipv6)
+        : mData({AF_INET6, IPV6_ADDR_BITS, 0U, 0U, {.v6 = ipv6}}) {}
+    IPAddress(const in6_addr& ipv6, uint32_t scope_id)
+        : mData({AF_INET6,
+                 IPV6_ADDR_BITS,
+                 0U,
+                 // Sanity check: scoped_ids only for link-local addresses.
+                 usesScopedIds(ipv6) ? scope_id : 0U,
+                 {.v6 = ipv6}}) {}
+    IPAddress(const IPAddress& ip, uint32_t scope_id) : IPAddress(ip) {
+        mData.scope_id = (family() == AF_INET6 && usesScopedIds(mData.ip.v6)) ? scope_id : 0U;
+    }
+
+    IPAddress& operator=(const IPAddress&) = default;
+    IPAddress& operator=(IPAddress&&) = default;
+
+    constexpr sa_family_t family() const noexcept { return mData.family; }
+    constexpr uint32_t scope_id() const noexcept { return mData.scope_id; }
+
+    std::string toString() const noexcept;
+
+    friend std::ostream& operator<<(std::ostream& os, const IPAddress& ip) {
+        os << ip.toString();
+        return os;
+    }
+    friend bool operator==(const IPAddress& a, const IPAddress& b) { return (a.mData == b.mData); }
+    friend bool operator!=(const IPAddress& a, const IPAddress& b) { return (a.mData != b.mData); }
+    friend bool operator<(const IPAddress& a, const IPAddress& b) { return (a.mData < b.mData); }
+    friend bool operator>(const IPAddress& a, const IPAddress& b) { return (b.mData < a.mData); }
+    friend bool operator<=(const IPAddress& a, const IPAddress& b) { return (a < b) || (a == b); }
+    friend bool operator>=(const IPAddress& a, const IPAddress& b) { return (b < a) || (a == b); }
+
+  private:
+    friend class IPPrefix;
+    friend class IPSockAddr;
+
+    explicit IPAddress(const internal_::compact_ipdata& ipdata) : mData(ipdata) {
+        mData.port = 0U;
+        switch (mData.family) {
+            case AF_INET:
+                mData.cidrlen = IPV4_ADDR_BITS;
+                mData.scope_id = 0U;
+                break;
+            case AF_INET6:
+                mData.cidrlen = IPV6_ADDR_BITS;
+                if (usesScopedIds(ipdata.ip.v6)) mData.scope_id = ipdata.scope_id;
+                break;
+            default:
+                mData.cidrlen = 0U;
+                mData.scope_id = 0U;
+                break;
+        }
+    }
+
+    internal_::compact_ipdata mData{};
+};
+
+class IPPrefix {
+  public:
+    static bool forString(const std::string& repr, IPPrefix* prefix);
+    static IPPrefix forString(const std::string& repr) {
+        IPPrefix prefix;
+        if (!forString(repr, &prefix)) return IPPrefix();
+        return prefix;
+    }
+
+    IPPrefix() = default;
+    IPPrefix(const IPPrefix&) = default;
+    IPPrefix(IPPrefix&&) = default;
+
+    explicit IPPrefix(const IPAddress& ip) : mData(ip.mData) {}
+
+    // Truncate the IP address |ip| at length |length|. Lengths greater than
+    // the address-family-relevant maximum, along with negative values, are
+    // interpreted as if the address-family-relevant maximum had been given.
+    IPPrefix(const IPAddress& ip, int length);
+
+    IPPrefix& operator=(const IPPrefix&) = default;
+    IPPrefix& operator=(IPPrefix&&) = default;
+
+    constexpr sa_family_t family() const noexcept { return mData.family; }
+    IPAddress ip() const noexcept { return IPAddress(mData); }
+    in_addr addr4() const noexcept { return mData.ip.v4; }
+    in6_addr addr6() const noexcept { return mData.ip.v6; }
+    constexpr int length() const noexcept { return mData.cidrlen; }
+
+    bool isUninitialized() const noexcept;
+    std::string toString() const noexcept;
+
+    friend std::ostream& operator<<(std::ostream& os, const IPPrefix& prefix) {
+        os << prefix.toString();
+        return os;
+    }
+    friend bool operator==(const IPPrefix& a, const IPPrefix& b) { return (a.mData == b.mData); }
+    friend bool operator!=(const IPPrefix& a, const IPPrefix& b) { return (a.mData != b.mData); }
+    friend bool operator<(const IPPrefix& a, const IPPrefix& b) { return (a.mData < b.mData); }
+    friend bool operator>(const IPPrefix& a, const IPPrefix& b) { return (b.mData < a.mData); }
+    friend bool operator<=(const IPPrefix& a, const IPPrefix& b) { return (a < b) || (a == b); }
+    friend bool operator>=(const IPPrefix& a, const IPPrefix& b) { return (b < a) || (a == b); }
+
+  private:
+    internal_::compact_ipdata mData{};
+};
+
+// An Internet socket address.
+//
+// Cannot represent other types of socket addresses (e.g. UNIX socket address, et cetera).
+class IPSockAddr {
+  public:
+    // TODO: static forString
+
+    static IPSockAddr toIPSockAddr(const std::string& repr, in_port_t port) {
+        return IPSockAddr(IPAddress::forString(repr), port);
+    }
+    static IPSockAddr toIPSockAddr(const sockaddr& sa) {
+        switch (sa.sa_family) {
+            case AF_INET:
+                return IPSockAddr(*reinterpret_cast<const sockaddr_in*>(&sa));
+            case AF_INET6:
+                return IPSockAddr(*reinterpret_cast<const sockaddr_in6*>(&sa));
+            default:
+                return IPSockAddr();
+        }
+    }
+    static IPSockAddr toIPSockAddr(const sockaddr_storage& ss) {
+        return toIPSockAddr(*reinterpret_cast<const sockaddr*>(&ss));
+    }
+
+    IPSockAddr() = default;
+    IPSockAddr(const IPSockAddr&) = default;
+    IPSockAddr(IPSockAddr&&) = default;
+
+    explicit IPSockAddr(const IPAddress& ip) : mData(ip.mData) {}
+    IPSockAddr(const IPAddress& ip, in_port_t port) : mData(ip.mData) { mData.port = port; }
+    explicit IPSockAddr(const sockaddr_in& ipv4sa)
+        : IPSockAddr(IPAddress(ipv4sa.sin_addr), ntohs(ipv4sa.sin_port)) {}
+    explicit IPSockAddr(const sockaddr_in6& ipv6sa)
+        : IPSockAddr(IPAddress(ipv6sa.sin6_addr, ipv6sa.sin6_scope_id), ntohs(ipv6sa.sin6_port)) {}
+
+    IPSockAddr& operator=(const IPSockAddr&) = default;
+    IPSockAddr& operator=(IPSockAddr&&) = default;
+
+    constexpr sa_family_t family() const noexcept { return mData.family; }
+    IPAddress ip() const noexcept { return IPAddress(mData); }
+    constexpr in_port_t port() const noexcept { return mData.port; }
+
+    // Implicit conversion to sockaddr_storage.
+    operator sockaddr_storage() const noexcept {
+        sockaddr_storage ss;
+        ss.ss_family = mData.family;
+        switch (mData.family) {
+            case AF_INET:
+                reinterpret_cast<sockaddr_in*>(&ss)->sin_addr = mData.ip.v4;
+                reinterpret_cast<sockaddr_in*>(&ss)->sin_port = htons(mData.port);
+                break;
+            case AF_INET6:
+                reinterpret_cast<sockaddr_in6*>(&ss)->sin6_addr = mData.ip.v6;
+                reinterpret_cast<sockaddr_in6*>(&ss)->sin6_port = htons(mData.port);
+                reinterpret_cast<sockaddr_in6*>(&ss)->sin6_scope_id = mData.scope_id;
+                break;
+        }
+        return ss;
+    }
+
+    std::string toString() const noexcept;
+
+    friend std::ostream& operator<<(std::ostream& os, const IPSockAddr& prefix) {
+        os << prefix.toString();
+        return os;
+    }
+    friend bool operator==(const IPSockAddr& a, const IPSockAddr& b) {
+        return (a.mData == b.mData);
+    }
+    friend bool operator!=(const IPSockAddr& a, const IPSockAddr& b) {
+        return (a.mData != b.mData);
+    }
+    friend bool operator<(const IPSockAddr& a, const IPSockAddr& b) { return (a.mData < b.mData); }
+    friend bool operator>(const IPSockAddr& a, const IPSockAddr& b) { return (b.mData < a.mData); }
+    friend bool operator<=(const IPSockAddr& a, const IPSockAddr& b) { return (a < b) || (a == b); }
+    friend bool operator>=(const IPSockAddr& a, const IPSockAddr& b) { return (b < a) || (a == b); }
+
+  private:
+    internal_::compact_ipdata mData{};
+};
+
+}  // namespace netdutils
+}  // namespace android
--- a/staticlibs/netd/libnetdutils/include/netdutils/Log.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/Log.h
@@ -0,0 +1,211 @@
+/*
+ * 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.
+ */
+
+#ifndef NETUTILS_LOG_H
+#define NETUTILS_LOG_H
+
+#include <chrono>
+#include <deque>
+#include <shared_mutex>
+#include <string>
+#include <type_traits>
+#include <vector>
+
+#include <android-base/stringprintf.h>
+#include <android-base/thread_annotations.h>
+
+#include <netdutils/Status.h>
+
+namespace android {
+namespace netdutils {
+
+class LogEntry {
+  public:
+    LogEntry() = default;
+    LogEntry(const LogEntry&) = default;
+    LogEntry(LogEntry&&) = default;
+    ~LogEntry() = default;
+    LogEntry& operator=(const LogEntry&) = default;
+    LogEntry& operator=(LogEntry&&) = default;
+
+    std::string toString() const;
+
+    ///
+    // Helper methods that make it easy to build up a LogEntry message.
+    // If performance becomes a factor the implementations could be inlined.
+    ///
+    LogEntry& message(const std::string& message);
+
+    // For calling with __FUNCTION__.
+    LogEntry& function(const std::string& function_name);
+    // For calling with __PRETTY_FUNCTION__.
+    LogEntry& prettyFunction(const std::string& pretty_function);
+
+    // Convenience methods for each of the common types of function arguments.
+    LogEntry& arg(const std::string& val);
+    // Intended for binary buffers, formats as hex
+    LogEntry& arg(const std::vector<uint8_t>& val);
+    LogEntry& arg(const std::vector<int32_t>& val);
+    LogEntry& arg(const std::vector<std::string>& val);
+    template <typename IntT, typename = std::enable_if_t<std::is_arithmetic_v<IntT>>>
+    LogEntry& arg(IntT val) {
+        mArgs.push_back(std::to_string(val));
+        return *this;
+    }
+    // Not using a plain overload here to avoid the implicit conversion from
+    // any pointer to bool, which causes string literals to print as 'true'.
+    template <>
+    LogEntry& arg<>(bool val);
+
+    template <typename... Args>
+    LogEntry& args(const Args&... a) {
+        // Cleverness ahead: we throw away the initializer_list filled with
+        // zeroes, all we care about is calling arg() for each argument.
+        (void) std::initializer_list<int>{(arg(a), 0)...};
+        return *this;
+    }
+
+    // Some things can return more than one value, or have multiple output
+    // parameters, so each of these adds to the mReturns vector.
+    LogEntry& returns(const std::string& rval);
+    LogEntry& returns(const Status& status);
+    LogEntry& returns(bool rval);
+    template <class T>
+    LogEntry& returns(T val) {
+        mReturns.push_back(std::to_string(val));
+        return *this;
+    }
+
+    LogEntry& withUid(uid_t uid);
+
+    // Append the duration computed since the creation of this instance.
+    LogEntry& withAutomaticDuration();
+    // Append the string-ified duration computed by some other means.
+    LogEntry& withDuration(const std::string& duration);
+
+  private:
+    std::chrono::steady_clock::time_point mStart = std::chrono::steady_clock::now();
+    std::string mMsg{};
+    std::string mFunc{};
+    std::vector<std::string> mArgs{};
+    std::vector<std::string> mReturns{};
+    std::string mUid{};
+    std::string mDuration{};
+};
+
+class Log {
+  public:
+    Log() = delete;
+    Log(const std::string& tag) : Log(tag, MAX_ENTRIES) {}
+    Log(const std::string& tag, size_t maxEntries) : mTag(tag), mMaxEntries(maxEntries) {}
+    Log(const Log&) = delete;
+    Log(Log&&) = delete;
+    ~Log();
+    Log& operator=(const Log&) = delete;
+    Log& operator=(Log&&) = delete;
+
+    LogEntry newEntry() const { return LogEntry(); }
+
+    // Record a log entry in internal storage only.
+    void log(const std::string& entry) { record(Level::LOG, entry); }
+    template <size_t n>
+    void log(const char entry[n]) { log(std::string(entry)); }
+    void log(const LogEntry& entry) { log(entry.toString()); }
+    void log(const char* fmt, ...) __attribute__((__format__(__printf__, 2, 3))) {
+        using ::android::base::StringAppendV;
+        std::string result;
+        va_list ap;
+        va_start(ap, fmt);
+        StringAppendV(&result, fmt, ap);
+        va_end(ap);
+        log(result);
+    }
+
+    // Record a log entry in internal storage and to ALOGI as well.
+    void info(const std::string& entry) { record(Level::INFO, entry); }
+    template <size_t n>
+    void info(const char entry[n]) { info(std::string(entry)); }
+    void info(const LogEntry& entry) { info(entry.toString()); }
+    void info(const char* fmt, ...) __attribute__((__format__(__printf__, 2, 3))) {
+        using ::android::base::StringAppendV;
+        std::string result;
+        va_list ap;
+        va_start(ap, fmt);
+        StringAppendV(&result, fmt, ap);
+        va_end(ap);
+        info(result);
+    }
+
+    // Record a log entry in internal storage and to ALOGW as well.
+    void warn(const std::string& entry) { record(Level::WARN, entry); }
+    template <size_t n>
+    void warn(const char entry[n]) { warn(std::string(entry)); }
+    void warn(const LogEntry& entry) { warn(entry.toString()); }
+    void warn(const char* fmt, ...) __attribute__((__format__(__printf__, 2, 3))) {
+        using ::android::base::StringAppendV;
+        std::string result;
+        va_list ap;
+        va_start(ap, fmt);
+        StringAppendV(&result, fmt, ap);
+        va_end(ap);
+        warn(result);
+    }
+
+    // Record a log entry in internal storage and to ALOGE as well.
+    void error(const std::string& entry) { record(Level::ERROR, entry); }
+    template <size_t n>
+    void error(const char entry[n]) { error(std::string(entry)); }
+    void error(const LogEntry& entry) { error(entry.toString()); }
+    void error(const char* fmt, ...) __attribute__((__format__(__printf__, 2, 3))) {
+        using ::android::base::StringAppendV;
+        std::string result;
+        va_list ap;
+        va_start(ap, fmt);
+        StringAppendV(&result, fmt, ap);
+        va_end(ap);
+        error(result);
+    }
+
+    // Iterates over every entry in the log in chronological order. Operates
+    // on a copy of the log entries, and so perEntryFn may itself call one of
+    // the logging functions if needed.
+    void forEachEntry(const std::function<void(const std::string&)>& perEntryFn) const;
+
+  private:
+    static constexpr const size_t MAX_ENTRIES = 750U;
+    const std::string mTag;
+    const size_t mMaxEntries;
+
+    // The LOG level adds an entry to mEntries but does not output the message
+    // to the system log. All other levels append to mEntries and output to the
+    // the system log.
+    enum class Level {
+        LOG,
+        INFO,
+        WARN,
+        ERROR,
+    };
+
+    void record(Level lvl, const std::string& entry);
+
+    mutable std::shared_mutex mLock;
+    std::deque<const std::string> mEntries;  // GUARDED_BY(mLock), when supported
+};
+
+}  // namespace netdutils
+}  // namespace android
+
+#endif /* NETUTILS_LOG_H */
--- a/staticlibs/netd/libnetdutils/include/netdutils/Math.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/Math.h
@@ -0,0 +1,40 @@
+/*
+ * 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.
+ */
+
+#ifndef NETUTILS_MATH_H
+#define NETUTILS_MATH_H
+
+#include <algorithm>
+#include <cstdint>
+
+namespace android {
+namespace netdutils {
+
+template <class T>
+inline constexpr const T mask(const int shift) {
+    return (1 << shift) - 1;
+}
+
+// Align x up to the nearest integer multiple of 2^shift
+template <class T>
+inline constexpr const T align(const T& x, const int shift) {
+    return (x + mask<T>(shift)) & ~mask<T>(shift);
+}
+
+}  // namespace netdutils
+}  // namespace android
+
+#endif /* NETUTILS_MATH_H */
--- a/staticlibs/netd/libnetdutils/include/netdutils/MemBlock.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/MemBlock.h
@@ -0,0 +1,67 @@
+/*
+ * 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.
+ */
+
+#ifndef NETUTILS_MEMBLOCK_H
+#define NETUTILS_MEMBLOCK_H
+
+#include <memory>
+#include "netdutils/Slice.h"
+
+namespace android {
+namespace netdutils {
+
+// A class to encapsulate self-deleting byte arrays while preserving access
+// to the underlying length (without the length being part of the type, e.g.
+// std::array<>). By design, the only interface to the underlying bytes is
+// via Slice, to encourage safer memory access usage.
+//
+// No thread-safety guarantees whatsoever.
+class MemBlock {
+  public:
+    MemBlock() : MemBlock(0U) {}
+    explicit MemBlock(size_t len)
+            : mData((len > 0U) ? new uint8_t[len]{} : nullptr),
+              mLen(len) {}
+    // Allocate memory of size src.size() and copy src into this MemBlock.
+    explicit MemBlock(Slice src) : MemBlock(src.size()) {
+        copy(get(), src);
+    }
+
+    // No copy construction or assignment.
+    MemBlock(const MemBlock&) = delete;
+    MemBlock& operator=(const MemBlock&) = delete;
+
+    // Move construction and assignment are okay.
+    MemBlock(MemBlock&&) = default;
+    MemBlock& operator=(MemBlock&&) = default;
+
+    // Even though this method is const, the memory wrapped by the
+    // returned Slice is mutable.
+    Slice get() const noexcept { return Slice(mData.get(), mLen); }
+
+    // Implicit cast to Slice.
+    // NOLINTNEXTLINE(google-explicit-constructor)
+    operator const Slice() const noexcept { return get(); }
+
+  private:
+    std::unique_ptr<uint8_t[]> mData;
+    size_t mLen;
+};
+
+}  // namespace netdutils
+}  // namespace android
+
+#endif /* NETUTILS_MEMBLOCK_H */
--- a/staticlibs/netd/libnetdutils/include/netdutils/Misc.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/Misc.h
@@ -0,0 +1,63 @@
+/*
+ * 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.
+ */
+
+#ifndef NETUTILS_MISC_H
+#define NETUTILS_MISC_H
+
+#include <map>
+
+namespace android {
+namespace netdutils {
+
+// Lookup key in map, returing a default value if key is not found
+template <typename U, typename V>
+inline const V& findWithDefault(const std::map<U, V>& map, const U& key, const V& dflt) {
+    auto it = map.find(key);
+    return (it == map.end()) ? dflt : it->second;
+}
+
+// Movable, copiable, scoped lambda (or std::function) runner. Useful
+// for running arbitrary cleanup or logging code when exiting a scope.
+//
+// Compare to defer in golang.
+template <typename FnT>
+class Cleanup {
+  public:
+    Cleanup() = delete;
+    explicit Cleanup(FnT fn) : mFn(fn) {}
+    ~Cleanup() { if (!mReleased) mFn(); }
+
+    void release() { mReleased = true; }
+
+  private:
+    bool mReleased{false};
+    FnT mFn;
+};
+
+// Helper to make a new Cleanup. Avoids complex or impossible syntax
+// when wrapping lambdas.
+//
+// Usage:
+// auto cleanup = makeCleanup([](){ your_code_here; });
+template <typename FnT>
+Cleanup<FnT> makeCleanup(FnT fn) {
+    return Cleanup<FnT>(fn);
+}
+
+}  // namespace netdutils
+}  // namespace android
+
+#endif /* NETUTILS_MISC_H */
--- a/staticlibs/netd/libnetdutils/include/netdutils/MockSyscalls.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/MockSyscalls.h
@@ -0,0 +1,90 @@
+/*
+ * 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.
+ */
+
+#ifndef NETUTILS_MOCK_SYSCALLS_H
+#define NETUTILS_MOCK_SYSCALLS_H
+
+#include <atomic>
+#include <cassert>
+#include <memory>
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+#include "netdutils/Syscalls.h"
+
+namespace android {
+namespace netdutils {
+
+class MockSyscalls : public Syscalls {
+  public:
+    virtual ~MockSyscalls() = default;
+    // Use Return(ByMove(...)) to deal with movable return types.
+    MOCK_CONST_METHOD3(open,
+                       StatusOr<UniqueFd>(const std::string& pathname, int flags, mode_t mode));
+    MOCK_CONST_METHOD3(socket, StatusOr<UniqueFd>(int domain, int type, int protocol));
+    MOCK_CONST_METHOD3(getsockname, Status(Fd sock, sockaddr* addr, socklen_t* addrlen));
+    MOCK_CONST_METHOD5(getsockopt, Status(Fd sock, int level, int optname, void* optval,
+                                          socklen_t *optlen));
+    MOCK_CONST_METHOD5(setsockopt, Status(Fd sock, int level, int optname, const void* optval,
+                                          socklen_t optlen));
+
+    MOCK_CONST_METHOD3(bind, Status(Fd sock, const sockaddr* addr, socklen_t addrlen));
+    MOCK_CONST_METHOD3(connect, Status(Fd sock, const sockaddr* addr, socklen_t addrlen));
+    MOCK_CONST_METHOD3(ioctl, StatusOr<ifreq>(Fd sock, unsigned long request, ifreq* ifr));
+
+    // Use Return(ByMove(...)) to deal with movable return types.
+    MOCK_CONST_METHOD2(eventfd, StatusOr<UniqueFd>(unsigned int initval, int flags));
+    MOCK_CONST_METHOD3(ppoll, StatusOr<int>(pollfd* fds, nfds_t nfds, double timeout));
+
+    MOCK_CONST_METHOD2(writev, StatusOr<size_t>(Fd fd, const std::vector<iovec>& iov));
+    MOCK_CONST_METHOD2(write, StatusOr<size_t>(Fd fd, const Slice buf));
+    MOCK_CONST_METHOD2(read, StatusOr<Slice>(Fd fd, const Slice buf));
+    MOCK_CONST_METHOD5(sendto, StatusOr<size_t>(Fd sock, const Slice buf, int flags,
+                                                const sockaddr* dst, socklen_t dstlen));
+    MOCK_CONST_METHOD5(recvfrom, StatusOr<Slice>(Fd sock, const Slice dst, int flags, sockaddr* src,
+                                                 socklen_t* srclen));
+    MOCK_CONST_METHOD2(shutdown, Status(Fd fd, int how));
+    MOCK_CONST_METHOD1(close, Status(Fd fd));
+
+    MOCK_CONST_METHOD2(fopen,
+                       StatusOr<UniqueFile>(const std::string& path, const std::string& mode));
+    MOCK_CONST_METHOD3(vfprintf, StatusOr<int>(FILE* file, const char* format, va_list ap));
+    MOCK_CONST_METHOD3(vfscanf, StatusOr<int>(FILE* file, const char* format, va_list ap));
+    MOCK_CONST_METHOD1(fclose, Status(FILE* file));
+    MOCK_CONST_METHOD0(fork, StatusOr<pid_t>());
+};
+
+// For the lifetime of this mock, replace the contents of sSyscalls
+// with a pointer to this mock. Behavior is undefined if multiple
+// ScopedMockSyscalls instances exist concurrently.
+class ScopedMockSyscalls : public MockSyscalls {
+  public:
+    ScopedMockSyscalls() : mOld(sSyscalls.swap(*this)) { assert((mRefcount++) == 1); }
+    virtual ~ScopedMockSyscalls() {
+        sSyscalls.swap(mOld);
+        assert((mRefcount--) == 0);
+    }
+
+  private:
+    std::atomic<int> mRefcount{0};
+    Syscalls& mOld;
+};
+
+}  // namespace netdutils
+}  // namespace android
+
+#endif /* NETUTILS_MOCK_SYSCALLS_H */
--- a/staticlibs/netd/libnetdutils/include/netdutils/Netfilter.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/Netfilter.h
@@ -0,0 +1,28 @@
+/*
+ * 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.
+ */
+
+#ifndef NETUTILS_NETFILTER_H
+#define NETUTILS_NETFILTER_H
+
+#include <ostream>
+
+#include <linux/netfilter.h>
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netlink.h>
+
+std::ostream& operator<<(std::ostream& os, const nfgenmsg& msg);
+
+#endif /* NETUTILS_NETFILTER_H */
--- a/staticlibs/netd/libnetdutils/include/netdutils/Netlink.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/Netlink.h
@@ -0,0 +1,55 @@
+/*
+ * 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.
+ */
+
+#ifndef NETUTILS_NETLINK_H
+#define NETUTILS_NETLINK_H
+
+#include <functional>
+#include <ostream>
+#include <linux/netlink.h>
+
+#include "netdutils/Slice.h"
+
+namespace android {
+namespace netdutils {
+
+// Invoke onMsg once for each netlink message in buf. onMsg will be
+// invoked with an aligned and deserialized header along with a Slice
+// containing the message payload.
+//
+// Assume that the first message begins at offset zero within buf.
+void forEachNetlinkMessage(const Slice buf,
+                           const std::function<void(const nlmsghdr&, const Slice)>& onMsg);
+
+// Invoke onAttr once for each netlink attribute in buf. onAttr will be
+// invoked with an aligned and deserialized header along with a Slice
+// containing the attribute payload.
+//
+// Assume that the first attribute begins at offset zero within buf.
+void forEachNetlinkAttribute(const Slice buf,
+                             const std::function<void(const nlattr&, const Slice)>& onAttr);
+
+}  // namespace netdutils
+}  // namespace android
+
+bool operator==(const sockaddr_nl& lhs, const sockaddr_nl& rhs);
+bool operator!=(const sockaddr_nl& lhs, const sockaddr_nl& rhs);
+
+std::ostream& operator<<(std::ostream& os, const nlmsghdr& hdr);
+std::ostream& operator<<(std::ostream& os, const nlattr& attr);
+std::ostream& operator<<(std::ostream& os, const sockaddr_nl& addr);
+
+#endif /* NETUTILS_NETLINK_H */
--- a/staticlibs/netd/libnetdutils/include/netdutils/NetworkConstants.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/NetworkConstants.h
@@ -0,0 +1,32 @@
+/*
+ * 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.
+ */
+
+#pragma once
+
+namespace android {
+namespace netdutils {
+
+// See also NetworkConstants.java in frameworks/base.
+constexpr int IPV4_ADDR_LEN = 4;
+constexpr int IPV4_ADDR_BITS = 32;
+constexpr int IPV6_ADDR_LEN = 16;
+constexpr int IPV6_ADDR_BITS = 128;
+
+// Referred from SHA256_DIGEST_LENGTH in boringssl
+constexpr size_t SHA256_SIZE = 32;
+
+}  // namespace netdutils
+}  // namespace android
--- a/staticlibs/netd/libnetdutils/include/netdutils/ResponseCode.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/ResponseCode.h
@@ -0,0 +1,92 @@
+/*
+ * Copyright (C) 2008 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.
+ */
+
+#ifndef NETDUTILS_RESPONSECODE_H
+#define NETDUTILS_RESPONSECODE_H
+
+namespace android {
+namespace netdutils {
+
+class ResponseCode {
+    // Keep in sync with
+    // frameworks/base/services/java/com/android/server/NetworkManagementService.java
+  public:
+    // 100 series - Requestion action was initiated; expect another reply
+    // before proceeding with a new command.
+    // clang-format off
+    static constexpr int ActionInitiated                = 100;
+    static constexpr int InterfaceListResult            = 110;
+    static constexpr int TetherInterfaceListResult      = 111;
+    static constexpr int TetherDnsFwdTgtListResult      = 112;
+    static constexpr int TtyListResult                  = 113;
+    static constexpr int TetheringStatsListResult       = 114;
+    static constexpr int TetherDnsFwdNetIdResult        = 115;
+
+    // 200 series - Requested action has been successfully completed
+    static constexpr int CommandOkay                    = 200;
+    static constexpr int TetherStatusResult             = 210;
+    static constexpr int IpFwdStatusResult              = 211;
+    static constexpr int InterfaceGetCfgResult          = 213;
+    // Formerly: int SoftapStatusResult                 = 214;
+    static constexpr int UsbRNDISStatusResult           = 215;
+    static constexpr int InterfaceRxCounterResult       = 216;
+    static constexpr int InterfaceTxCounterResult       = 217;
+    static constexpr int InterfaceRxThrottleResult      = 218;
+    static constexpr int InterfaceTxThrottleResult      = 219;
+    static constexpr int QuotaCounterResult             = 220;
+    static constexpr int TetheringStatsResult           = 221;
+    // NOTE: keep synced with bionic/libc/dns/net/gethnamaddr.c
+    static constexpr int DnsProxyQueryResult            = 222;
+    static constexpr int ClatdStatusResult              = 223;
+
+    // 400 series - The command was accepted but the requested action
+    // did not take place.
+    static constexpr int OperationFailed                = 400;
+    static constexpr int DnsProxyOperationFailed        = 401;
+    static constexpr int ServiceStartFailed             = 402;
+    static constexpr int ServiceStopFailed              = 403;
+
+    // 500 series - The command was not accepted and the requested
+    // action did not take place.
+    static constexpr int CommandSyntaxError             = 500;
+    static constexpr int CommandParameterError          = 501;
+
+    // 600 series - Unsolicited broadcasts
+    static constexpr int InterfaceChange                = 600;
+    static constexpr int BandwidthControl               = 601;
+    static constexpr int ServiceDiscoveryFailed         = 602;
+    static constexpr int ServiceDiscoveryServiceAdded   = 603;
+    static constexpr int ServiceDiscoveryServiceRemoved = 604;
+    static constexpr int ServiceRegistrationFailed      = 605;
+    static constexpr int ServiceRegistrationSucceeded   = 606;
+    static constexpr int ServiceResolveFailed           = 607;
+    static constexpr int ServiceResolveSuccess          = 608;
+    static constexpr int ServiceSetHostnameFailed       = 609;
+    static constexpr int ServiceSetHostnameSuccess      = 610;
+    static constexpr int ServiceGetAddrInfoFailed       = 611;
+    static constexpr int ServiceGetAddrInfoSuccess      = 612;
+    static constexpr int InterfaceClassActivity         = 613;
+    static constexpr int InterfaceAddressChange         = 614;
+    static constexpr int InterfaceDnsInfo               = 615;
+    static constexpr int RouteChange                    = 616;
+    static constexpr int StrictCleartext                = 617;
+    // clang-format on
+};
+
+}  // namespace netdutils
+}  // namespace android
+
+#endif  // NETDUTILS_RESPONSECODE_H
--- a/staticlibs/netd/libnetdutils/include/netdutils/Slice.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/Slice.h
@@ -0,0 +1,161 @@
+/*
+ * 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.
+ */
+
+#ifndef NETUTILS_SLICE_H
+#define NETUTILS_SLICE_H
+
+#include <algorithm>
+#include <array>
+#include <cstring>
+#include <ostream>
+#include <tuple>
+#include <vector>
+
+namespace android {
+namespace netdutils {
+
+// Immutable wrapper for a linear region of unowned bytes.
+// Slice represents memory as a half-closed interval [base, limit).
+//
+// Note that without manually invoking the Slice() constructor, it is
+// impossible to increase the size of a slice. This guarantees that
+// applications that properly use the slice API will never access
+// memory outside of a slice.
+//
+// Note that const Slice still wraps mutable memory, however copy
+// assignment and move assignment to slice are disabled.
+class Slice {
+  public:
+    Slice() = default;
+
+    // Create a slice beginning at base and continuing to but not including limit
+    Slice(void* base, void* limit) : mBase(toUint8(base)), mLimit(toUint8(limit)) {}
+
+    // Create a slice beginning at base and continuing for size bytes
+    Slice(void* base, size_t size) : Slice(base, toUint8(base) + size) {}
+
+    // Return the address of the first byte in this slice
+    uint8_t* base() const { return mBase; }
+
+    // Return the address of the first byte following this slice
+    uint8_t* limit() const { return mLimit; }
+
+    // Return the size of this slice in bytes
+    size_t size() const { return limit() - base(); }
+
+    // Return true if size() == 0
+    bool empty() const { return base() == limit(); }
+
+  private:
+    static uint8_t* toUint8(void* ptr) { return reinterpret_cast<uint8_t*>(ptr); }
+
+    uint8_t* mBase = nullptr;
+    uint8_t* mLimit = nullptr;
+};
+
+// Return slice representation of ref which must be a POD type
+template <typename T>
+inline const Slice makeSlice(const T& ref) {
+    static_assert(std::is_pod<T>::value, "value must be a POD type");
+    static_assert(!std::is_pointer<T>::value, "value must not be a pointer type");
+    return {const_cast<T*>(&ref), sizeof(ref)};
+}
+
+// Return slice representation of string data()
+inline const Slice makeSlice(const std::string& s) {
+    using ValueT = std::string::value_type;
+    return {const_cast<ValueT*>(s.data()), s.size() * sizeof(ValueT)};
+}
+
+// Return slice representation of vector data()
+template <typename T>
+inline const Slice makeSlice(const std::vector<T>& v) {
+    return {const_cast<T*>(v.data()), v.size() * sizeof(T)};
+}
+
+// Return slice representation of array data()
+template <typename U, size_t V>
+inline const Slice makeSlice(const std::array<U, V>& a) {
+    return {const_cast<U*>(a.data()), a.size() * sizeof(U)};
+}
+
+// Return prefix and suffix of Slice s ending and starting at position cut
+inline std::pair<const Slice, const Slice> split(const Slice s, size_t cut) {
+    const size_t tmp = std::min(cut, s.size());
+    return {{s.base(), s.base() + tmp}, {s.base() + tmp, s.limit()}};
+}
+
+// Return prefix of Slice s ending at position cut
+inline const Slice take(const Slice s, size_t cut) {
+    return std::get<0>(split(s, cut));
+}
+
+// Return suffix of Slice s starting at position cut
+inline const Slice drop(const Slice s, size_t cut) {
+    return std::get<1>(split(s, cut));
+}
+
+// Copy from src into dst. Bytes copied is the lesser of dst.size() and src.size()
+inline size_t copy(const Slice dst, const Slice src) {
+    const auto min = std::min(dst.size(), src.size());
+    memcpy(dst.base(), src.base(), min);
+    return min;
+}
+
+// Base case for variadic extract below
+template <typename Head>
+inline size_t extract(const Slice src, Head& head) {
+    return copy(makeSlice(head), src);
+}
+
+// Copy from src into one or more pointers to POD data.  If src.size()
+// is less than the sum of all data pointers a suffix of data will be
+// left unmodified. Return the number of bytes copied.
+template <typename Head, typename... Tail>
+inline size_t extract(const Slice src, Head& head, Tail&... tail) {
+    const auto extracted = extract(src, head);
+    return extracted + extract(drop(src, extracted), tail...);
+}
+
+// Return a string containing a copy of the contents of s
+std::string toString(const Slice s);
+
+// Return a string containing a hexadecimal representation of the contents of s.
+// This function inserts a newline into its output every wrap bytes.
+std::string toHex(const Slice s, int wrap = INT_MAX);
+
+inline bool operator==(const Slice& lhs, const Slice& rhs) {
+    return (lhs.base() == rhs.base()) && (lhs.limit() == rhs.limit());
+}
+
+inline bool operator!=(const Slice& lhs, const Slice& rhs) {
+    return !(lhs == rhs);
+}
+
+std::ostream& operator<<(std::ostream& os, const Slice& slice);
+
+// Return suffix of Slice s starting at the first match of byte c. If no matched
+// byte, return an empty Slice.
+inline const Slice findFirstMatching(const Slice s, uint8_t c) {
+    uint8_t* match = (uint8_t*)memchr(s.base(), c, s.size());
+    if (!match) return Slice();
+    return drop(s, match - s.base());
+}
+
+}  // namespace netdutils
+}  // namespace android
+
+#endif /* NETUTILS_SLICE_H */
--- a/staticlibs/netd/libnetdutils/include/netdutils/Socket.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/Socket.h
@@ -0,0 +1,44 @@
+/*
+ * 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.
+ */
+
+#ifndef NETDUTILS_SOCKET_H
+#define NETDUTILS_SOCKET_H
+
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <string>
+
+#include "netdutils/StatusOr.h"
+
+namespace android {
+namespace netdutils {
+
+inline sockaddr* asSockaddrPtr(void* addr) {
+    return reinterpret_cast<sockaddr*>(addr);
+}
+
+inline const sockaddr* asSockaddrPtr(const void* addr) {
+    return reinterpret_cast<const sockaddr*>(addr);
+}
+
+// Return a string representation of addr or Status if there was a
+// failure during conversion.
+StatusOr<std::string> toString(const in6_addr& addr);
+
+}  // namespace netdutils
+}  // namespace android
+
+#endif /* NETDUTILS_SOCKET_H */
--- a/staticlibs/netd/libnetdutils/include/netdutils/SocketOption.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/SocketOption.h
@@ -0,0 +1,60 @@
+/*
+ * 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.
+ */
+
+#ifndef NETDUTILS_SOCKETOPTION_H
+#define NETDUTILS_SOCKETOPTION_H
+
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <string>
+
+#include "netdutils/Fd.h"
+#include "netdutils/Status.h"
+
+namespace android {
+namespace netdutils {
+
+// Turn on simple "boolean" socket options.
+//
+// This is simple wrapper for options that are enabled via code of the form:
+//
+//     int on = 1;
+//     setsockopt(..., &on, sizeof(on));
+Status enableSockopt(Fd sock, int level, int optname);
+
+// Turn on TCP keepalives, and set keepalive parameters for this socket.
+//
+// A parameter value of zero does not set that parameter.
+//
+// Typical system defaults are:
+//
+//     idleTime (in seconds)
+//     $ cat /proc/sys/net/ipv4/tcp_keepalive_time
+//     7200
+//
+//     numProbes
+//     $ cat /proc/sys/net/ipv4/tcp_keepalive_probes
+//     9
+//
+//     probeInterval (in seconds)
+//     $ cat /proc/sys/net/ipv4/tcp_keepalive_intvl
+//     75
+Status enableTcpKeepAlives(Fd sock, unsigned idleTime, unsigned numProbes, unsigned probeInterval);
+
+}  // namespace netdutils
+}  // namespace android
+
+#endif /* NETDUTILS_SOCKETOPTION_H */
--- a/staticlibs/netd/libnetdutils/include/netdutils/Status.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/Status.h
@@ -0,0 +1,136 @@
+/*
+ * 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.
+ */
+
+#ifndef NETUTILS_STATUS_H
+#define NETUTILS_STATUS_H
+
+#include <cassert>
+#include <limits>
+#include <ostream>
+
+#include <android-base/result.h>
+
+namespace android {
+namespace netdutils {
+
+// Simple status implementation suitable for use on the stack in low
+// or moderate performance code. This can definitely be improved but
+// for now short string optimization is expected to keep the common
+// success case fast.
+//
+// Status is implicitly movable via the default noexcept move constructor
+// and noexcept move-assignment operator.
+class [[nodiscard]] Status {
+  public:
+    Status() = default;
+    explicit Status(int code) : mCode(code) {}
+
+    // Constructs an error Status, |code| must be non-zero.
+    Status(int code, std::string msg) : mCode(code), mMsg(std::move(msg)) { assert(!ok()); }
+
+    Status(android::base::Result<void> result)
+        : mCode(result.ok() ? 0 : result.error().code()),
+          mMsg(result.ok() ? "" : result.error().message()) {}
+
+    int code() const { return mCode; }
+
+    bool ok() const { return code() == 0; }
+
+    const std::string& msg() const { return mMsg; }
+
+    // Explicitly ignores the Status without triggering [[nodiscard]] errors.
+    void ignoreError() const {}
+
+    bool operator==(const Status& other) const { return code() == other.code(); }
+    bool operator!=(const Status& other) const { return !(*this == other); }
+
+  private:
+    int mCode = 0;
+    std::string mMsg;
+};
+
+namespace status {
+
+const Status ok{0};
+// EOF is not part of errno space, we'll place it far above the
+// highest existing value.
+const Status eof{0x10001, "end of file"};
+const Status undefined{std::numeric_limits<int>::max(), "undefined"};
+
+}  // namespace status
+
+// Return true if status is "OK". This is sometimes preferable to
+// status.ok() when we want to check the state of Status-like objects
+// that implicitly cast to Status.
+inline bool isOk(const Status& status) {
+    return status.ok();
+}
+
+// For use only in tests. Used for both Status and Status-like objects. See also isOk().
+#define EXPECT_OK(status) EXPECT_TRUE(isOk(status))
+#define ASSERT_OK(status) ASSERT_TRUE(isOk(status))
+
+// Documents that status is expected to be ok. This function may log
+// (or assert when running in debug mode) if status has an unexpected value.
+inline void expectOk(const Status& /*status*/) {
+    // TODO: put something here, for now this function serves solely as documentation.
+}
+
+// Convert POSIX errno to a Status object.
+// If Status is extended to have more features, this mapping may
+// become more complex.
+Status statusFromErrno(int err, const std::string& msg);
+
+// Helper that checks Status-like object (notably StatusOr) against a
+// value in the errno space.
+bool equalToErrno(const Status& status, int err);
+
+// Helper that converts Status-like object (notably StatusOr) to a
+// message.
+std::string toString(const Status& status);
+
+std::ostream& operator<<(std::ostream& os, const Status& s);
+
+// Evaluate 'stmt' to a Status object and if it results in an error, return that
+// error.  Use 'tmp' as a variable name to avoid shadowing any variables named
+// tmp.
+#define RETURN_IF_NOT_OK_IMPL(tmp, stmt)           \
+    do {                                           \
+        ::android::netdutils::Status tmp = (stmt); \
+        if (!isOk(tmp)) {                          \
+            return tmp;                            \
+        }                                          \
+    } while (false)
+
+// Create a unique variable name to avoid shadowing local variables.
+#define RETURN_IF_NOT_OK_CONCAT(line, stmt) RETURN_IF_NOT_OK_IMPL(__CONCAT(_status_, line), stmt)
+
+// Macro to allow exception-like handling of error return values.
+//
+// If the evaluation of stmt results in an error, return that error
+// from current function.
+//
+// Example usage:
+// Status bar() { ... }
+//
+// RETURN_IF_NOT_OK(status);
+// RETURN_IF_NOT_OK(bar());
+#define RETURN_IF_NOT_OK(stmt) RETURN_IF_NOT_OK_CONCAT(__LINE__, stmt)
+
+}  // namespace netdutils
+}  // namespace android
+
+#endif /* NETUTILS_STATUS_H */
--- a/staticlibs/netd/libnetdutils/include/netdutils/StatusOr.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/StatusOr.h
@@ -0,0 +1,119 @@
+/*
+ * 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.
+ */
+
+#ifndef NETUTILS_STATUSOR_H
+#define NETUTILS_STATUSOR_H
+
+#include <cassert>
+#include "netdutils/Status.h"
+
+namespace android {
+namespace netdutils {
+
+// Wrapper around a combination of Status and application value type.
+// T may be any copyable or movable type.
+template <typename T>
+class [[nodiscard]] StatusOr {
+  public:
+    // Constructs a new StatusOr with status::undefined status.
+    // This is marked 'explicit' to try to catch cases like 'return {};',
+    // where people think StatusOr<std::vector<int>> will be initialized
+    // with an empty vector, instead of a status::undefined.
+    explicit StatusOr() = default;
+
+    // Implicit copy constructor and construction from T.
+    // NOLINTNEXTLINE(google-explicit-constructor)
+    StatusOr(Status status) : mStatus(std::move(status)) { assert(!isOk(mStatus)); }
+
+    // Implicit construction from T. It is convenient and sensible to be able
+    // to do 'return T()' when the return type is StatusOr<T>.
+    // NOLINTNEXTLINE(google-explicit-constructor)
+    StatusOr(const T& value) : mStatus(status::ok), mValue(value) {}
+    // NOLINTNEXTLINE(google-explicit-constructor)
+    StatusOr(T&& value) : mStatus(status::ok), mValue(std::move(value)) {}
+
+    // Move constructor ok (if T supports move)
+    StatusOr(StatusOr&&) noexcept = default;
+    // Move assignment ok (if T supports move)
+    StatusOr& operator=(StatusOr&&) noexcept = default;
+    // Copy constructor ok (if T supports copy)
+    StatusOr(const StatusOr&) = default;
+    // Copy assignment ok (if T supports copy)
+    StatusOr& operator=(const StatusOr&) = default;
+
+    // Returns a const reference to wrapped type.
+    // It is an error to call value() when !isOk(status())
+    const T& value() const & { return mValue; }
+    const T&& value() const && { return mValue; }
+
+    // Returns an rvalue reference to wrapped type
+    // It is an error to call value() when !isOk(status())
+    //
+    // If T is expensive to copy but supports efficient move, it can be moved
+    // out of a StatusOr as follows:
+    //   T value = std::move(statusor).value();
+    T& value() & { return mValue; }
+    T&& value() && { return mValue; }
+
+    // Returns the Status object assigned at construction time.
+    const Status status() const { return mStatus; }
+
+    // Explicitly ignores the Status without triggering [[nodiscard]] errors.
+    void ignoreError() const {}
+
+    // Implicit cast to Status.
+    // NOLINTNEXTLINE(google-explicit-constructor)
+    operator Status() const { return status(); }
+
+  private:
+    Status mStatus = status::undefined;
+    T mValue;
+};
+
+template <typename T>
+inline std::ostream& operator<<(std::ostream& os, const StatusOr<T>& s) {
+    return os << "StatusOr[status: " << s.status() << "]";
+}
+
+#define ASSIGN_OR_RETURN_IMPL(tmp, lhs, stmt) \
+    auto tmp = (stmt);                        \
+    RETURN_IF_NOT_OK(tmp);                    \
+    lhs = std::move(tmp.value());
+
+#define ASSIGN_OR_RETURN_CONCAT(line, lhs, stmt) \
+    ASSIGN_OR_RETURN_IMPL(__CONCAT(_status_or_, line), lhs, stmt)
+
+// Macro to allow exception-like handling of error return values.
+//
+// If the evaluation of stmt results in an error, return that error
+// from the current function. Otherwise, assign the result to lhs.
+//
+// This macro supports both move and copy assignment operators. lhs
+// may be either a new local variable or an existing non-const
+// variable accessible in the current scope.
+//
+// Example usage:
+// StatusOr<MyType> foo() { ... }
+//
+// ASSIGN_OR_RETURN(auto myVar, foo());
+// ASSIGN_OR_RETURN(myExistingVar, foo());
+// ASSIGN_OR_RETURN(myMemberVar, foo());
+#define ASSIGN_OR_RETURN(lhs, stmt) ASSIGN_OR_RETURN_CONCAT(__LINE__, lhs, stmt)
+
+}  // namespace netdutils
+}  // namespace android
+
+#endif /* NETUTILS_STATUSOR_H */
--- a/staticlibs/netd/libnetdutils/include/netdutils/Stopwatch.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/Stopwatch.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+#ifndef NETDUTILS_STOPWATCH_H
+#define NETDUTILS_STOPWATCH_H
+
+#include <chrono>
+
+namespace android {
+namespace netdutils {
+
+class Stopwatch {
+  private:
+    using clock = std::chrono::steady_clock;
+    using time_point = std::chrono::time_point<clock>;
+
+  public:
+    Stopwatch() : mStart(clock::now()) {}
+    virtual ~Stopwatch() = default;
+
+    int64_t timeTakenUs() const { return getElapsedUs(clock::now()); }
+    int64_t getTimeAndResetUs() {
+        const auto& now = clock::now();
+        int64_t elapsed = getElapsedUs(now);
+        mStart = now;
+        return elapsed;
+    }
+
+  private:
+    time_point mStart;
+
+    int64_t getElapsedUs(const time_point& now) const {
+        return (std::chrono::duration_cast<std::chrono::microseconds>(now - mStart)).count();
+    }
+};
+
+}  // namespace netdutils
+}  // namespace android
+
+#endif  // NETDUTILS_STOPWATCH_H
--- a/staticlibs/netd/libnetdutils/include/netdutils/Syscalls.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/Syscalls.h
@@ -0,0 +1,204 @@
+/*
+ * 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.
+ */
+
+#ifndef NETDUTILS_SYSCALLS_H
+#define NETDUTILS_SYSCALLS_H
+
+#include <memory>
+
+#include <net/if.h>
+#include <poll.h>
+#include <sys/eventfd.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <sys/uio.h>
+#include <unistd.h>
+
+#include "netdutils/Fd.h"
+#include "netdutils/Slice.h"
+#include "netdutils/Socket.h"
+#include "netdutils/Status.h"
+#include "netdutils/StatusOr.h"
+#include "netdutils/UniqueFd.h"
+#include "netdutils/UniqueFile.h"
+
+namespace android {
+namespace netdutils {
+
+class Syscalls {
+  public:
+    virtual ~Syscalls() = default;
+
+    virtual StatusOr<UniqueFd> open(const std::string& pathname, int flags,
+                                    mode_t mode = 0) const = 0;
+
+    virtual StatusOr<UniqueFd> socket(int domain, int type, int protocol) const = 0;
+
+    virtual Status getsockname(Fd sock, sockaddr* addr, socklen_t* addrlen) const = 0;
+
+    virtual Status getsockopt(Fd sock, int level, int optname, void *optval,
+                              socklen_t *optlen) const = 0;
+
+    virtual Status setsockopt(Fd sock, int level, int optname, const void* optval,
+                              socklen_t optlen) const = 0;
+
+    virtual Status bind(Fd sock, const sockaddr* addr, socklen_t addrlen) const = 0;
+
+    virtual Status connect(Fd sock, const sockaddr* addr, socklen_t addrlen) const = 0;
+
+    virtual StatusOr<ifreq> ioctl(Fd sock, unsigned long request, ifreq* ifr) const = 0;
+
+    virtual StatusOr<UniqueFd> eventfd(unsigned int initval, int flags) const = 0;
+
+    virtual StatusOr<int> ppoll(pollfd* fds, nfds_t nfds, double timeout) const = 0;
+
+    virtual StatusOr<size_t> writev(Fd fd, const std::vector<iovec>& iov) const = 0;
+
+    virtual StatusOr<size_t> write(Fd fd, const Slice buf) const = 0;
+
+    virtual StatusOr<Slice> read(Fd fd, const Slice buf) const = 0;
+
+    virtual StatusOr<size_t> sendto(Fd sock, const Slice buf, int flags, const sockaddr* dst,
+                                    socklen_t dstlen) const = 0;
+
+    virtual StatusOr<Slice> recvfrom(Fd sock, const Slice dst, int flags, sockaddr* src,
+                                     socklen_t* srclen) const = 0;
+
+    virtual Status shutdown(Fd fd, int how) const = 0;
+
+    virtual Status close(Fd fd) const = 0;
+
+    virtual StatusOr<UniqueFile> fopen(const std::string& path, const std::string& mode) const = 0;
+
+    virtual StatusOr<int> vfprintf(FILE* file, const char* format, va_list ap) const = 0;
+
+    virtual StatusOr<int> vfscanf(FILE* file, const char* format, va_list ap) const = 0;
+
+    virtual Status fclose(FILE* file) const = 0;
+
+    virtual StatusOr<pid_t> fork() const = 0;
+
+    // va_args helpers
+    // va_start doesn't work when the preceding argument is a reference
+    // type so we're forced to use const char*.
+    StatusOr<int> fprintf(FILE* file, const char* format, ...) const {
+        va_list ap;
+        va_start(ap, format);
+        auto result = vfprintf(file, format, ap);
+        va_end(ap);
+        return result;
+    }
+
+    // va_start doesn't work when the preceding argument is a reference
+    // type so we're forced to use const char*.
+    StatusOr<int> fscanf(FILE* file, const char* format, ...) const {
+        va_list ap;
+        va_start(ap, format);
+        auto result = vfscanf(file, format, ap);
+        va_end(ap);
+        return result;
+    }
+
+    // Templated helpers that forward directly to methods declared above
+    template <typename SockaddrT>
+    StatusOr<SockaddrT> getsockname(Fd sock) const {
+        SockaddrT addr = {};
+        socklen_t addrlen = sizeof(addr);
+        RETURN_IF_NOT_OK(getsockname(sock, asSockaddrPtr(&addr), &addrlen));
+        return addr;
+    }
+
+    template <typename SockoptT>
+    Status getsockopt(Fd sock, int level, int optname, void* optval, socklen_t* optlen) const {
+        return getsockopt(sock, level, optname, optval, optlen);
+    }
+
+    template <typename SockoptT>
+    Status setsockopt(Fd sock, int level, int optname, const SockoptT& opt) const {
+        return setsockopt(sock, level, optname, &opt, sizeof(opt));
+    }
+
+    template <typename SockaddrT>
+    Status bind(Fd sock, const SockaddrT& addr) const {
+        return bind(sock, asSockaddrPtr(&addr), sizeof(addr));
+    }
+
+    template <typename SockaddrT>
+    Status connect(Fd sock, const SockaddrT& addr) const {
+        return connect(sock, asSockaddrPtr(&addr), sizeof(addr));
+    }
+
+    template <size_t size>
+    StatusOr<std::array<uint16_t, size>> ppoll(const std::array<Fd, size>& fds, uint16_t events,
+                                               double timeout) const {
+        std::array<pollfd, size> tmp;
+        for (size_t i = 0; i < size; ++i) {
+            tmp[i].fd = fds[i].get();
+            tmp[i].events = events;
+            tmp[i].revents = 0;
+        }
+        RETURN_IF_NOT_OK(ppoll(tmp.data(), tmp.size(), timeout).status());
+        std::array<uint16_t, size> out;
+        for (size_t i = 0; i < size; ++i) {
+            out[i] = tmp[i].revents;
+        }
+        return out;
+    }
+
+    template <typename SockaddrT>
+    StatusOr<size_t> sendto(Fd sock, const Slice buf, int flags, const SockaddrT& dst) const {
+        return sendto(sock, buf, flags, asSockaddrPtr(&dst), sizeof(dst));
+    }
+
+    // Ignore src sockaddr
+    StatusOr<Slice> recvfrom(Fd sock, const Slice dst, int flags) const {
+        return recvfrom(sock, dst, flags, nullptr, nullptr);
+    }
+
+    template <typename SockaddrT>
+    StatusOr<std::pair<Slice, SockaddrT>> recvfrom(Fd sock, const Slice dst, int flags) const {
+        SockaddrT addr = {};
+        socklen_t addrlen = sizeof(addr);
+        ASSIGN_OR_RETURN(auto used, recvfrom(sock, dst, flags, asSockaddrPtr(&addr), &addrlen));
+        return std::make_pair(used, addr);
+    }
+};
+
+// Specialized singleton that supports zero initialization and runtime
+// override of contained pointer.
+class SyscallsHolder {
+  public:
+    ~SyscallsHolder();
+
+    // Return a pointer to an unowned instance of Syscalls.
+    Syscalls& get();
+
+    // Testing only: set the value returned by getSyscalls. Return the old value.
+    // Callers are responsible for restoring the previous value returned
+    // by getSyscalls to avoid leaks.
+    Syscalls& swap(Syscalls& syscalls);
+
+  private:
+    std::atomic<Syscalls*> mSyscalls{nullptr};
+};
+
+// Syscalls instance used throughout netdutils
+extern SyscallsHolder sSyscalls;
+
+}  // namespace netdutils
+}  // namespace android
+
+#endif /* NETDUTILS_SYSCALLS_H */
--- a/staticlibs/netd/libnetdutils/include/netdutils/ThreadUtil.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/ThreadUtil.h
@@ -0,0 +1,83 @@
+/*
+ * 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.
+ */
+
+#ifndef NETDUTILS_THREADUTIL_H
+#define NETDUTILS_THREADUTIL_H
+
+#include <pthread.h>
+#include <memory>
+
+#include <android-base/logging.h>
+
+namespace android {
+namespace netdutils {
+
+struct scoped_pthread_attr {
+    scoped_pthread_attr() { pthread_attr_init(&attr); }
+    ~scoped_pthread_attr() { pthread_attr_destroy(&attr); }
+
+    int detach() { return -pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); }
+
+    pthread_attr_t attr;
+};
+
+inline void setThreadName(std::string name) {
+    // MAX_TASK_COMM_LEN=16 is not exported by bionic.
+    const size_t MAX_TASK_COMM_LEN = 16;
+
+    // Crop name to 16 bytes including the NUL byte, as required by pthread_setname_np()
+    if (name.size() >= MAX_TASK_COMM_LEN) name.resize(MAX_TASK_COMM_LEN - 1);
+
+    if (int ret = pthread_setname_np(pthread_self(), name.c_str()); ret != 0) {
+        LOG(WARNING) << "Unable to set thread name to " << name << ": " << strerror(ret);
+    }
+}
+
+template <typename T>
+inline void* runAndDelete(void* obj) {
+    std::unique_ptr<T> handler(reinterpret_cast<T*>(obj));
+    setThreadName(handler->threadName().c_str());
+    handler->run();
+    return nullptr;
+}
+
+template <typename T>
+inline int threadLaunch(T* obj) {
+    if (obj == nullptr) {
+        return -EINVAL;
+    }
+
+    scoped_pthread_attr scoped_attr;
+
+    int rval = scoped_attr.detach();
+    if (rval != 0) {
+        return rval;
+    }
+
+    pthread_t thread;
+    rval = pthread_create(&thread, &scoped_attr.attr, &runAndDelete<T>, obj);
+    if (rval != 0) {
+        LOG(WARNING) << __func__ << ": pthread_create failed: " << rval;
+        return -rval;
+    }
+
+    return rval;
+}
+
+}  // namespace netdutils
+}  // namespace android
+
+#endif  // NETDUTILS_THREADUTIL_H
--- a/staticlibs/netd/libnetdutils/include/netdutils/UidConstants.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/UidConstants.h
@@ -0,0 +1,27 @@
+/*
+ * 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.
+ */
+
+#ifndef NETDUTILS_UID_CONSTANTS_H
+#define NETDUTILS_UID_CONSTANTS_H
+
+// These are used by both eBPF kernel programs and netd, we cannot put them in NetdConstant.h since
+// we have to minimize the number of headers included by the BPF kernel program.
+#define MIN_SYSTEM_UID 0
+#define MAX_SYSTEM_UID 9999
+
+#define PER_USER_RANGE 100000
+
+#endif  // NETDUTILS_UID_CONSTANTS_H
--- a/staticlibs/netd/libnetdutils/include/netdutils/UniqueFd.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/UniqueFd.h
@@ -0,0 +1,71 @@
+/*
+ * 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.
+ */
+
+#ifndef NETUTILS_UNIQUEFD_H
+#define NETUTILS_UNIQUEFD_H
+
+#include <unistd.h>
+#include <ostream>
+
+#include "netdutils/Fd.h"
+
+namespace android {
+namespace netdutils {
+
+// Stricter unique_fd implementation that:
+// *) Does not implement release()
+// *) Does not implicitly cast to int
+// *) Uses a strongly typed wrapper (Fd) for the underlying file descriptor
+//
+// Users of UniqueFd should endeavor to treat this as a completely
+// opaque object. The only code that should interpret the wrapped
+// value is in Syscalls.h
+class UniqueFd {
+  public:
+    UniqueFd() = default;
+
+    UniqueFd(Fd fd) : mFd(fd) {}
+
+    ~UniqueFd() { reset(); }
+
+    // Disallow copy
+    UniqueFd(const UniqueFd&) = delete;
+    UniqueFd& operator=(const UniqueFd&) = delete;
+
+    // Allow move
+    UniqueFd(UniqueFd&& other) { std::swap(mFd, other.mFd); }
+    UniqueFd& operator=(UniqueFd&& other) {
+        std::swap(mFd, other.mFd);
+        return *this;
+    }
+
+    // Cleanup any currently owned Fd, replacing it with the optional
+    // parameter fd
+    void reset(Fd fd = Fd());
+
+    // Implict cast to Fd
+    operator const Fd &() const { return mFd; }
+
+  private:
+    Fd mFd;
+};
+
+std::ostream& operator<<(std::ostream& os, const UniqueFd& fd);
+
+}  // namespace netdutils
+}  // namespace android
+
+#endif /* NETUTILS_UNIQUEFD_H */
--- a/staticlibs/netd/libnetdutils/include/netdutils/UniqueFile.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/UniqueFile.h
@@ -0,0 +1,35 @@
+/*
+ * 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.
+ */
+
+#ifndef NETDUTILS_UNIQUEFILE_H
+#define NETDUTILS_UNIQUEFILE_H
+
+#include <stdio.h>
+#include <memory>
+
+namespace android {
+namespace netdutils {
+
+struct UniqueFileDtor {
+    void operator()(FILE* file) const;
+};
+
+using UniqueFile = std::unique_ptr<FILE, UniqueFileDtor>;
+
+}  // namespace netdutils
+}  // namespace android
+
+#endif /* NETDUTILS_UNIQUEFILE_H */