diff --git a/tetheroffload/aidl/vts/functional/Android.bp b/tetheroffload/aidl/vts/functional/Android.bp
new file mode 100644
index 0000000..c9c1845
--- /dev/null
+++ b/tetheroffload/aidl/vts/functional/Android.bp
@@ -0,0 +1,24 @@
+package {
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+cc_test {
+    name: "VtsHalTetheroffloadTargetTest",
+    defaults: [
+        "VtsHalTargetTestDefaults",
+        "use_libaidlvintf_gtest_helper_static",
+    ],
+    srcs: [
+        "VtsHalTetheroffloadTargetTest.cpp",
+    ],
+    shared_libs: [
+        "libbinder_ndk",
+    ],
+    static_libs: [
+        "android.hardware.tetheroffload-V1-ndk",
+        "libgmock_ndk",
+    ],
+    test_suites: [
+        "vts",
+    ],
+}
diff --git a/tetheroffload/aidl/vts/functional/VtsHalTetheroffloadTargetTest.cpp b/tetheroffload/aidl/vts/functional/VtsHalTetheroffloadTargetTest.cpp
new file mode 100644
index 0000000..fc8abbd
--- /dev/null
+++ b/tetheroffload/aidl/vts/functional/VtsHalTetheroffloadTargetTest.cpp
@@ -0,0 +1,689 @@
+/*
+ * Copyright (C) 2022 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.
+ */
+
+#define LOG_TAG "tetheroffload_aidl_hal_test"
+
+#include <aidl/Gtest.h>
+#include <aidl/Vintf.h>
+#include <aidl/android/hardware/tetheroffload/BnOffload.h>
+#include <aidl/android/hardware/tetheroffload/BnTetheringOffloadCallback.h>
+#include <android-base/logging.h>
+#include <android-base/unique_fd.h>
+#include <android/binder_manager.h>
+#include <android/binder_process.h>
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <log/log.h>
+#include <net/if.h>
+#include <sys/socket.h>
+
+namespace aidl::android::hardware::tetheroffload {
+
+namespace {
+
+using ::android::base::unique_fd;
+using android::hardware::tetheroffload::ForwardedStats;
+using android::hardware::tetheroffload::IOffload;
+using android::hardware::tetheroffload::NatTimeoutUpdate;
+using android::hardware::tetheroffload::OffloadCallbackEvent;
+using ::testing::AnyOf;
+using ::testing::Eq;
+
+const std::string TEST_IFACE = "rmnet_data0";
+const unsigned kFd1Groups = NF_NETLINK_CONNTRACK_NEW | NF_NETLINK_CONNTRACK_DESTROY;
+const unsigned kFd2Groups = NF_NETLINK_CONNTRACK_UPDATE | NF_NETLINK_CONNTRACK_DESTROY;
+
+enum class ExpectBoolean {
+    Ignored = -1,
+    False = 0,
+    True = 1,
+};
+
+inline const sockaddr* asSockaddr(const sockaddr_nl* nladdr) {
+    return reinterpret_cast<const sockaddr*>(nladdr);
+}
+
+int netlinkSocket(int protocol, unsigned groups) {
+    unique_fd s(socket(AF_NETLINK, SOCK_DGRAM, protocol));
+    if (s.get() < 0) {
+        return -errno;
+    }
+
+    const struct sockaddr_nl bind_addr = {
+            .nl_family = AF_NETLINK,
+            .nl_pad = 0,
+            .nl_pid = 0,
+            .nl_groups = groups,
+    };
+    if (bind(s.get(), asSockaddr(&bind_addr), sizeof(bind_addr)) != 0) {
+        return -errno;
+    }
+
+    const struct sockaddr_nl kernel_addr = {
+            .nl_family = AF_NETLINK,
+            .nl_pad = 0,
+            .nl_pid = 0,
+            .nl_groups = groups,
+    };
+    if (connect(s.get(), asSockaddr(&kernel_addr), sizeof(kernel_addr)) != 0) {
+        return -errno;
+    }
+
+    return s.release();
+}
+
+int netlinkSocket(unsigned groups) {
+    return netlinkSocket(NETLINK_NETFILTER, groups);
+}
+
+// Check whether the specified interface is up.
+bool interfaceIsUp(const std::string name) {
+    struct ifreq ifr = {};
+    strlcpy(ifr.ifr_name, name.c_str(), sizeof(ifr.ifr_name));
+    int sock = socket(AF_INET6, SOCK_DGRAM, 0);
+    if (sock == -1) return false;
+    int ret = ioctl(sock, SIOCGIFFLAGS, &ifr, sizeof(ifr));
+    close(sock);
+    return (ret == 0) && (ifr.ifr_flags & IFF_UP);
+}
+
+// Callback class for both events and NAT timeout updates.
+class TetheringOffloadCallback : public BnTetheringOffloadCallback {
+  public:
+    ndk::ScopedAStatus onEvent(OffloadCallbackEvent in_event) override {
+        auto lock = std::lock_guard{mMutex};
+        mOnEventInvoked = true;
+        mLastEvent = in_event;
+        mNotifyCv.notify_all();
+        return ndk::ScopedAStatus::ok();
+    }
+
+    ndk::ScopedAStatus updateTimeout(const NatTimeoutUpdate& in_params) override {
+        auto lock = std::lock_guard{mMutex};
+        mOnUpdateTimeoutInvoked = true;
+        mNatTimeout = in_params;
+        mNotifyCv.notify_all();
+        return ndk::ScopedAStatus::ok();
+    }
+
+  private:
+    std::mutex mMutex;
+    std::condition_variable mNotifyCv;
+    OffloadCallbackEvent mLastEvent;
+    NatTimeoutUpdate mNatTimeout;
+    bool mOnEventInvoked = false;
+    bool mOnUpdateTimeoutInvoked = false;
+};
+
+// The common base class for tetheroffload AIDL HAL tests.
+class TetheroffloadAidlTestBase : public testing::TestWithParam<std::string> {
+  public:
+    virtual void SetUp() override { getService(); }
+    virtual void TearDown() override {
+        // For good measure, the teardown should try stopOffload() once more, since
+        // different HAL call test cycles might enter this function. Also the
+        // return code cannot be actually expected for all cases, hence ignore it.
+        stopOffload(ExpectBoolean::Ignored);
+    };
+
+  protected:
+    void getService() {
+        AIBinder* binder = AServiceManager_waitForService(GetParam().c_str());
+        ASSERT_NE(binder, nullptr);
+        mOffload = IOffload::fromBinder(ndk::SpAIBinder(binder));
+    }
+
+    void initOffload(const bool expectedResult) {
+        unique_fd ufd1(netlinkSocket(kFd1Groups));
+        if (ufd1.get() < 0) {
+            ALOGE("Unable to create conntrack sockets: %d/%s", errno, strerror(errno));
+            FAIL();
+        }
+        ndk::ScopedFileDescriptor fd1 = ndk::ScopedFileDescriptor(ufd1.release());
+
+        unique_fd ufd2(netlinkSocket(kFd2Groups));
+        if (ufd2.get() < 0) {
+            ALOGE("Unable to create conntrack sockets: %d/%s", errno, strerror(errno));
+            FAIL();
+        }
+        ndk::ScopedFileDescriptor fd2 = ndk::ScopedFileDescriptor(ufd2.release());
+
+        mTetheringOffloadCallback = ndk::SharedRefBase::make<TetheringOffloadCallback>();
+        ASSERT_NE(mTetheringOffloadCallback, nullptr) << "Could not get offload callback";
+
+        ASSERT_EQ(mOffload->initOffload(fd1, fd2, mTetheringOffloadCallback).getExceptionCode(),
+                  expectedResult ? EX_NONE : EX_ILLEGAL_STATE);
+    }
+
+    void stopOffload(const ExpectBoolean expectedResult) {
+        ndk::ScopedAStatus status = mOffload->stopOffload();
+        if (expectedResult == ExpectBoolean::Ignored) return;
+        ASSERT_EQ(status.getExceptionCode(),
+                  expectedResult == ExpectBoolean::True ? EX_NONE : EX_ILLEGAL_STATE);
+    }
+
+    std::shared_ptr<IOffload> mOffload;
+    std::shared_ptr<TetheringOffloadCallback> mTetheringOffloadCallback;
+};
+
+// The test class for tetheroffload before initialization.
+class TetheroffloadAidlPreInitTest : public TetheroffloadAidlTestBase {
+  public:
+    virtual void SetUp() override { getService(); }
+};
+
+// The main test class for tetheroffload AIDL HAL.
+class TetheroffloadAidlGeneralTest : public TetheroffloadAidlTestBase {
+  public:
+    virtual void SetUp() override {
+        getService();
+        initOffload(true);
+    }
+};
+
+// Passing invalid file descriptor to initOffload() should return an error.
+// Check that this occurs when both FDs are empty.
+TEST_P(TetheroffloadAidlPreInitTest, TestInitOffloadInvalidFdsReturnsError) {
+    ndk::ScopedFileDescriptor fd1 = ndk::ScopedFileDescriptor(-1);
+    ndk::ScopedFileDescriptor fd2 = ndk::ScopedFileDescriptor(-1);
+    mTetheringOffloadCallback = ndk::SharedRefBase::make<TetheringOffloadCallback>();
+    ASSERT_NE(mTetheringOffloadCallback, nullptr) << "Could not get offload callback";
+    EXPECT_THAT(mOffload->initOffload(fd1, fd2, mTetheringOffloadCallback).getExceptionCode(),
+                AnyOf(Eq(EX_ILLEGAL_ARGUMENT), Eq(EX_TRANSACTION_FAILED)));
+}
+
+// Passing invalid file descriptor to initOffload() should return an error.
+// Check that this occurs when FD1 is empty.
+TEST_P(TetheroffloadAidlPreInitTest, TestInitOffloadInvalidFd1ReturnsError) {
+    ndk::ScopedFileDescriptor fd1 = ndk::ScopedFileDescriptor(-1);
+    unique_fd ufd2(netlinkSocket(kFd2Groups));
+    if (ufd2.get() < 0) {
+        ALOGE("Unable to create conntrack sockets: %d/%s", errno, strerror(errno));
+        FAIL();
+    }
+    ndk::ScopedFileDescriptor fd2 = ndk::ScopedFileDescriptor(ufd2.release());
+    mTetheringOffloadCallback = ndk::SharedRefBase::make<TetheringOffloadCallback>();
+    ASSERT_NE(mTetheringOffloadCallback, nullptr) << "Could not get offload callback";
+    EXPECT_THAT(mOffload->initOffload(fd1, fd2, mTetheringOffloadCallback).getExceptionCode(),
+                AnyOf(Eq(EX_ILLEGAL_ARGUMENT), Eq(EX_TRANSACTION_FAILED)));
+}
+
+// Passing invalid file descriptor to initOffload() should return an error.
+// Check that this occurs when FD2 is empty.
+TEST_P(TetheroffloadAidlPreInitTest, TestInitOffloadInvalidFd2ReturnsError) {
+    unique_fd ufd1(netlinkSocket(kFd1Groups));
+    if (ufd1.get() < 0) {
+        ALOGE("Unable to create conntrack sockets: %d/%s", errno, strerror(errno));
+        FAIL();
+    }
+    ndk::ScopedFileDescriptor fd1 = ndk::ScopedFileDescriptor(ufd1.release());
+    ndk::ScopedFileDescriptor fd2 = ndk::ScopedFileDescriptor(-1);
+    mTetheringOffloadCallback = ndk::SharedRefBase::make<TetheringOffloadCallback>();
+    ASSERT_NE(mTetheringOffloadCallback, nullptr) << "Could not get offload callback";
+    EXPECT_THAT(mOffload->initOffload(fd1, fd2, mTetheringOffloadCallback).getExceptionCode(),
+                AnyOf(Eq(EX_ILLEGAL_ARGUMENT), Eq(EX_TRANSACTION_FAILED)));
+}
+
+// Call initOffload() multiple times. Check that non-first initOffload() calls return error.
+TEST_P(TetheroffloadAidlPreInitTest, AdditionalInitsWithoutStopReturnError) {
+    initOffload(true);
+    initOffload(false);
+    initOffload(false);
+    initOffload(false);
+}
+
+// Check that calling stopOffload() without first having called initOffload() returns error.
+TEST_P(TetheroffloadAidlPreInitTest, MultipleStopsWithoutInitReturnError) {
+    stopOffload(ExpectBoolean::False);
+    stopOffload(ExpectBoolean::False);
+    stopOffload(ExpectBoolean::False);
+}
+
+// Check that calling stopOffload() after a complete init/stop cycle returns error.
+TEST_P(TetheroffloadAidlPreInitTest, AdditionalStopsWithInitReturnError) {
+    initOffload(true);
+    // Call setUpstreamParameters() so that "offload" can be reasonably said
+    // to be both requested and operational.
+    const std::string iface(TEST_IFACE);
+    const std::string v4Addr("192.0.0.2");
+    const std::string v4Gw("192.0.0.1");
+    const std::vector<std::string> v6Gws{std::string("fe80::db8:1"), std::string("fe80::db8:2")};
+    EXPECT_TRUE(mOffload->setUpstreamParameters(iface, v4Addr, v4Gw, v6Gws).isOk());
+    if (!interfaceIsUp(TEST_IFACE)) {
+        return;
+    }
+    SCOPED_TRACE("Expecting stopOffload to succeed");
+    stopOffload(ExpectBoolean::True);  // balance out initOffload(true)
+    SCOPED_TRACE("Expecting stopOffload to fail the first time");
+    stopOffload(ExpectBoolean::False);
+    SCOPED_TRACE("Expecting stopOffload to fail the second time");
+    stopOffload(ExpectBoolean::False);
+}
+
+// Check that calling setLocalPrefixes() without first having called initOffload() returns error.
+TEST_P(TetheroffloadAidlPreInitTest, SetLocalPrefixesWithoutInitReturnsError) {
+    const std::vector<std::string> prefixes{std::string("2001:db8::/64")};
+    EXPECT_EQ(mOffload->setLocalPrefixes(prefixes).getExceptionCode(), EX_ILLEGAL_STATE);
+}
+
+// Check that calling getForwardedStats() without first having called initOffload()
+// returns zero bytes statistics.
+TEST_P(TetheroffloadAidlPreInitTest, GetForwardedStatsWithoutInitReturnsZeroValues) {
+    const std::string upstream(TEST_IFACE);
+    ForwardedStats stats;
+    EXPECT_TRUE(mOffload->getForwardedStats(upstream, &stats).isOk());
+    EXPECT_EQ(stats.rxBytes, 0ULL);
+    EXPECT_EQ(stats.txBytes, 0ULL);
+}
+
+// Check that calling setDataWarningAndLimit() without first having called initOffload() returns
+// error.
+TEST_P(TetheroffloadAidlPreInitTest, SetDataWarningAndLimitWithoutInitReturnsError) {
+    const std::string upstream(TEST_IFACE);
+    const int64_t warning = 5000LL;
+    const int64_t limit = 5000LL;
+    EXPECT_EQ(mOffload->setDataWarningAndLimit(upstream, warning, limit).getExceptionCode(),
+              EX_ILLEGAL_STATE);
+}
+
+// Check that calling setUpstreamParameters() without first having called initOffload()
+// returns error.
+TEST_P(TetheroffloadAidlPreInitTest, SetUpstreamParametersWithoutInitReturnsError) {
+    const std::string iface(TEST_IFACE);
+    const std::string v4Addr("192.0.2.0/24");
+    const std::string v4Gw("192.0.2.1");
+    const std::vector<std::string> v6Gws{std::string("fe80::db8:1")};
+    EXPECT_EQ(mOffload->setUpstreamParameters(iface, v4Addr, v4Gw, v6Gws).getExceptionCode(),
+              EX_ILLEGAL_STATE);
+}
+
+// Check that calling addDownstream() with an IPv4 prefix without first having called
+// initOffload() returns error.
+TEST_P(TetheroffloadAidlPreInitTest, AddIPv4DownstreamWithoutInitReturnsError) {
+    const std::string iface(TEST_IFACE);
+    const std::string prefix("192.0.2.0/24");
+    EXPECT_EQ(mOffload->addDownstream(iface, prefix).getExceptionCode(), EX_ILLEGAL_STATE);
+}
+
+// Check that calling addDownstream() with an IPv6 prefix without first having called
+// initOffload() returns error.
+TEST_P(TetheroffloadAidlPreInitTest, AddIPv6DownstreamWithoutInitReturnsError) {
+    const std::string iface(TEST_IFACE);
+    const std::string prefix("2001:db8::/64");
+    EXPECT_EQ(mOffload->addDownstream(iface, prefix).getExceptionCode(), EX_ILLEGAL_STATE);
+}
+
+// Check that calling removeDownstream() with an IPv4 prefix without first having called
+// initOffload() returns error.
+TEST_P(TetheroffloadAidlPreInitTest, RemoveIPv4DownstreamWithoutInitReturnsError) {
+    const std::string iface(TEST_IFACE);
+    const std::string prefix("192.0.2.0/24");
+    EXPECT_EQ(mOffload->removeDownstream(iface, prefix).getExceptionCode(), EX_ILLEGAL_STATE);
+}
+
+// Check that calling removeDownstream() with an IPv6 prefix without first having called
+// initOffload() returns error.
+TEST_P(TetheroffloadAidlPreInitTest, RemoveIPv6DownstreamWithoutInitReturnsError) {
+    const std::string iface(TEST_IFACE);
+    const std::string prefix("2001:db8::/64");
+    EXPECT_EQ(mOffload->removeDownstream(iface, prefix).getExceptionCode(), EX_ILLEGAL_STATE);
+}
+
+/*
+ * Tests for IOffload::setLocalPrefixes().
+ */
+
+// Test setLocalPrefixes() rejects an IPv4 address.
+TEST_P(TetheroffloadAidlGeneralTest, SetLocalPrefixesIPv4AddressFails) {
+    const std::vector<std::string> prefixes{std::string("192.0.2.1")};
+    EXPECT_EQ(mOffload->setLocalPrefixes(prefixes).getExceptionCode(), EX_ILLEGAL_ARGUMENT);
+}
+
+// Test setLocalPrefixes() rejects an IPv6 address.
+TEST_P(TetheroffloadAidlGeneralTest, SetLocalPrefixesIPv6AddressFails) {
+    const std::vector<std::string> prefixes{std::string("fe80::1")};
+    EXPECT_EQ(mOffload->setLocalPrefixes(prefixes).getExceptionCode(), EX_ILLEGAL_ARGUMENT);
+}
+
+// Test setLocalPrefixes() accepts both IPv4 and IPv6 prefixes.
+TEST_P(TetheroffloadAidlGeneralTest, SetLocalPrefixesIPv4v6PrefixesOk) {
+    const std::vector<std::string> prefixes{std::string("192.0.2.0/24"), std::string("fe80::/64")};
+    EXPECT_TRUE(mOffload->setLocalPrefixes(prefixes).isOk());
+}
+
+// Test that setLocalPrefixes() fails given empty input. There is always
+// a non-empty set of local prefixes; when all networking interfaces are down
+// we still apply {127.0.0.0/8, ::1/128, fe80::/64} here.
+TEST_P(TetheroffloadAidlGeneralTest, SetLocalPrefixesEmptyFails) {
+    const std::vector<std::string> prefixes{};
+    EXPECT_EQ(mOffload->setLocalPrefixes(prefixes).getExceptionCode(), EX_ILLEGAL_ARGUMENT);
+}
+
+// Test setLocalPrefixes() fails on incorrectly formed input strings.
+TEST_P(TetheroffloadAidlGeneralTest, SetLocalPrefixesInvalidFails) {
+    const std::vector<std::string> prefixes{std::string("192.0.2.0/24"), std::string("invalid")};
+    EXPECT_EQ(mOffload->setLocalPrefixes(prefixes).getExceptionCode(), EX_ILLEGAL_ARGUMENT);
+}
+
+/*
+ * Tests for IOffload::getForwardedStats().
+ */
+
+// Test that getForwardedStats() for a non-existent upstream yields zero bytes statistics.
+TEST_P(TetheroffloadAidlGeneralTest, GetForwardedStatsInvalidUpstreamIface) {
+    const std::string upstream("invalid");
+    ForwardedStats stats;
+    EXPECT_TRUE(mOffload->getForwardedStats(upstream, &stats).isOk());
+    EXPECT_EQ(stats.rxBytes, 0ULL);
+    EXPECT_EQ(stats.txBytes, 0ULL);
+}
+
+// TEST_IFACE is presumed to exist on the device and be up. No packets
+// are ever actually caused to be forwarded.
+TEST_P(TetheroffloadAidlGeneralTest, GetForwardedStatsDummyIface) {
+    const std::string upstream(TEST_IFACE);
+    ForwardedStats stats;
+    EXPECT_TRUE(mOffload->getForwardedStats(upstream, &stats).isOk());
+    EXPECT_EQ(stats.rxBytes, 0ULL);
+    EXPECT_EQ(stats.txBytes, 0ULL);
+}
+
+/*
+ * Tests for IOffload::setDataWarningAndLimit().
+ */
+
+// Test that setDataWarningAndLimit() for an empty interface name fails.
+TEST_P(TetheroffloadAidlGeneralTest, SetDataWarningAndLimitEmptyUpstreamIfaceFails) {
+    const std::string upstream("");
+    const int64_t warning = 12345LL;
+    const int64_t limit = 67890LL;
+    EXPECT_THAT(mOffload->setDataWarningAndLimit(upstream, warning, limit).getExceptionCode(),
+                AnyOf(Eq(EX_ILLEGAL_ARGUMENT), Eq(EX_UNSUPPORTED_OPERATION)));
+}
+
+// TEST_IFACE is presumed to exist on the device and be up. No packets
+// are ever actually caused to be forwarded.
+TEST_P(TetheroffloadAidlGeneralTest, SetDataWarningAndLimitNonZeroOk) {
+    const std::string upstream(TEST_IFACE);
+    const int64_t warning = 4000LL;
+    const int64_t limit = 5000LL;
+    EXPECT_THAT(mOffload->setDataWarningAndLimit(upstream, warning, limit).getExceptionCode(),
+                AnyOf(Eq(EX_NONE), Eq(EX_UNSUPPORTED_OPERATION)));
+}
+
+// TEST_IFACE is presumed to exist on the device and be up. No packets
+// are ever actually caused to be forwarded.
+TEST_P(TetheroffloadAidlGeneralTest, SetDataWarningAndLimitZeroOk) {
+    const std::string upstream(TEST_IFACE);
+    const int64_t warning = 0LL;
+    const int64_t limit = 0LL;
+    EXPECT_THAT(mOffload->setDataWarningAndLimit(upstream, warning, limit).getExceptionCode(),
+                AnyOf(Eq(EX_NONE), Eq(EX_UNSUPPORTED_OPERATION)));
+}
+
+// TEST_IFACE is presumed to exist on the device and be up. No packets
+// are ever actually caused to be forwarded.
+TEST_P(TetheroffloadAidlGeneralTest, SetDataWarningAndLimitUnlimitedWarningOk) {
+    const std::string upstream(TEST_IFACE);
+    const int64_t warning = LLONG_MAX;
+    const int64_t limit = 5000LL;
+    EXPECT_TRUE(mOffload->setDataWarningAndLimit(upstream, warning, limit).isOk());
+}
+
+// Test that setDataWarningAndLimit() with negative thresholds fails.
+TEST_P(TetheroffloadAidlGeneralTest, SetDataWarningAndLimitNegativeFails) {
+    const std::string upstream(TEST_IFACE);
+    const int64_t warning = -1LL;
+    const int64_t limit = -1LL;
+    EXPECT_THAT(mOffload->setDataWarningAndLimit(upstream, warning, limit).getExceptionCode(),
+                AnyOf(Eq(EX_ILLEGAL_ARGUMENT), Eq(EX_UNSUPPORTED_OPERATION)));
+}
+
+/*
+ * Tests for IOffload::setUpstreamParameters().
+ */
+
+// TEST_IFACE is presumed to exist on the device and be up. No packets
+// are ever actually caused to be forwarded.
+TEST_P(TetheroffloadAidlGeneralTest, SetUpstreamParametersIPv6OnlyOk) {
+    const std::string iface(TEST_IFACE);
+    const std::string v4Addr("");
+    const std::string v4Gw("");
+    const std::vector<std::string> v6Gws{std::string("fe80::db8:1"), std::string("fe80::db8:2")};
+    EXPECT_TRUE(mOffload->setUpstreamParameters(iface, v4Addr, v4Gw, v6Gws).isOk());
+}
+
+// TEST_IFACE is presumed to exist on the device and be up. No packets
+// are ever actually caused to be forwarded.
+TEST_P(TetheroffloadAidlGeneralTest, SetUpstreamParametersAlternateIPv6OnlyOk) {
+    const std::string iface(TEST_IFACE);
+    const std::string v4Addr("");
+    const std::string v4Gw("");
+    const std::vector<std::string> v6Gws{std::string("fe80::db8:1"), std::string("fe80::db8:3")};
+    EXPECT_TRUE(mOffload->setUpstreamParameters(iface, v4Addr, v4Gw, v6Gws).isOk());
+}
+
+// TEST_IFACE is presumed to exist on the device and be up. No packets
+// are ever actually caused to be forwarded.
+TEST_P(TetheroffloadAidlGeneralTest, SetUpstreamParametersIPv4OnlyOk) {
+    const std::string iface(TEST_IFACE);
+    const std::string v4Addr("192.0.2.2");
+    const std::string v4Gw("192.0.2.1");
+    const std::vector<std::string> v6Gws{};
+    EXPECT_TRUE(mOffload->setUpstreamParameters(iface, v4Addr, v4Gw, v6Gws).isOk());
+}
+
+// TEST_IFACE is presumed to exist on the device and be up. No packets
+// are ever actually caused to be forwarded.
+TEST_P(TetheroffloadAidlGeneralTest, SetUpstreamParametersIPv4v6Ok) {
+    const std::string iface(TEST_IFACE);
+    const std::string v4Addr("192.0.2.2");
+    const std::string v4Gw("192.0.2.1");
+    const std::vector<std::string> v6Gws{std::string("fe80::db8:1"), std::string("fe80::db8:2")};
+    EXPECT_TRUE(mOffload->setUpstreamParameters(iface, v4Addr, v4Gw, v6Gws).isOk());
+}
+
+// Test that setUpstreamParameters() fails when all parameters are empty.
+TEST_P(TetheroffloadAidlGeneralTest, SetUpstreamParametersEmptyFails) {
+    const std::string iface("");
+    const std::string v4Addr("");
+    const std::string v4Gw("");
+    const std::vector<std::string> v6Gws{};
+    EXPECT_EQ(mOffload->setUpstreamParameters(iface, v4Addr, v4Gw, v6Gws).getExceptionCode(),
+              EX_ILLEGAL_ARGUMENT);
+}
+
+// Test that setUpstreamParameters() fails when given empty or non-existent interface names.
+TEST_P(TetheroffloadAidlGeneralTest, SetUpstreamParametersBogusIfaceFails) {
+    const std::string v4Addr("192.0.2.2");
+    const std::string v4Gw("192.0.2.1");
+    const std::vector<std::string> v6Gws{std::string("fe80::db8:1")};
+    for (const auto& bogus : {"", "invalid"}) {
+        SCOPED_TRACE(testing::Message() << "upstream: " << bogus);
+        const std::string iface(bogus);
+        EXPECT_EQ(mOffload->setUpstreamParameters(iface, v4Addr, v4Gw, v6Gws).getExceptionCode(),
+                  EX_ILLEGAL_ARGUMENT);
+    }
+}
+
+// Test that setUpstreamParameters() fails when given unparseable IPv4 addresses.
+TEST_P(TetheroffloadAidlGeneralTest, SetUpstreamParametersInvalidIPv4AddrFails) {
+    const std::string iface(TEST_IFACE);
+    const std::string v4Gw("192.0.2.1");
+    const std::vector<std::string> v6Gws{std::string("fe80::db8:1")};
+    for (const auto& bogus : {"invalid", "192.0.2"}) {
+        SCOPED_TRACE(testing::Message() << "v4addr: " << bogus);
+        const std::string v4Addr(bogus);
+        EXPECT_EQ(mOffload->setUpstreamParameters(iface, v4Addr, v4Gw, v6Gws).getExceptionCode(),
+                  EX_ILLEGAL_ARGUMENT);
+    }
+}
+
+// Test that setUpstreamParameters() fails when given unparseable IPv4 gateways.
+TEST_P(TetheroffloadAidlGeneralTest, SetUpstreamParametersInvalidIPv4GatewayFails) {
+    const std::string iface(TEST_IFACE);
+    const std::string v4Addr("192.0.2.2");
+    const std::vector<std::string> v6Gws{std::string("fe80::db8:1")};
+    for (const auto& bogus : {"invalid", "192.0.2"}) {
+        SCOPED_TRACE(testing::Message() << "v4gateway: " << bogus);
+        const std::string v4Gw(bogus);
+        EXPECT_EQ(mOffload->setUpstreamParameters(iface, v4Addr, v4Gw, v6Gws).getExceptionCode(),
+                  EX_ILLEGAL_ARGUMENT);
+    }
+}
+
+// Test that setUpstreamParameters() fails when given unparseable IPv6 gateways.
+TEST_P(TetheroffloadAidlGeneralTest, SetUpstreamParametersBadIPv6GatewaysFail) {
+    const std::string iface(TEST_IFACE);
+    const std::string v4Addr("192.0.2.2");
+    const std::string v4Gw("192.0.2.1");
+    for (const auto& bogus : {"", "invalid", "fe80::bogus", "192.0.2.66"}) {
+        SCOPED_TRACE(testing::Message() << "v6gateway: " << bogus);
+        const std::vector<std::string> v6Gws{std::string("fe80::1"), std::string(bogus)};
+        EXPECT_EQ(mOffload->setUpstreamParameters(iface, v4Addr, v4Gw, v6Gws).getExceptionCode(),
+                  EX_ILLEGAL_ARGUMENT);
+    }
+}
+
+/*
+ * Tests for IOffload::addDownstream().
+ */
+
+// Test addDownstream() works given an IPv4 prefix.
+TEST_P(TetheroffloadAidlGeneralTest, AddDownstreamIPv4) {
+    const std::string iface("dummy0");
+    const std::string prefix("192.0.2.0/24");
+    EXPECT_TRUE(mOffload->addDownstream(iface, prefix).isOk());
+}
+
+// Test addDownstream() works given an IPv6 prefix.
+TEST_P(TetheroffloadAidlGeneralTest, AddDownstreamIPv6) {
+    const std::string iface("dummy0");
+    const std::string prefix("2001:db8::/64");
+    EXPECT_TRUE(mOffload->addDownstream(iface, prefix).isOk());
+}
+
+// Test addDownstream() fails given all empty parameters.
+TEST_P(TetheroffloadAidlGeneralTest, AddDownstreamEmptyFails) {
+    const std::string iface("");
+    const std::string prefix("");
+    EXPECT_EQ(mOffload->addDownstream(iface, prefix).getExceptionCode(), EX_ILLEGAL_ARGUMENT);
+}
+
+// Test addDownstream() fails given empty or non-existent interface names.
+TEST_P(TetheroffloadAidlGeneralTest, AddDownstreamInvalidIfaceFails) {
+    const std::string prefix("192.0.2.0/24");
+    for (const auto& bogus : {"", "invalid"}) {
+        SCOPED_TRACE(testing::Message() << "iface: " << bogus);
+        const std::string iface(bogus);
+        EXPECT_EQ(mOffload->addDownstream(iface, prefix).getExceptionCode(), EX_ILLEGAL_ARGUMENT);
+    }
+}
+
+// Test addDownstream() fails given unparseable prefix arguments.
+TEST_P(TetheroffloadAidlGeneralTest, AddDownstreamBogusPrefixFails) {
+    const std::string iface("dummy0");
+    for (const auto& bogus : {"", "192.0.2/24", "2001:db8/64"}) {
+        SCOPED_TRACE(testing::Message() << "prefix: " << bogus);
+        const std::string prefix(bogus);
+        EXPECT_EQ(mOffload->addDownstream(iface, prefix).getExceptionCode(), EX_ILLEGAL_ARGUMENT);
+    }
+}
+
+/*
+ * Tests for IOffload::removeDownstream().
+ */
+
+// Test removeDownstream() works given an IPv4 prefix.
+TEST_P(TetheroffloadAidlGeneralTest, RemoveDownstreamIPv4) {
+    const std::string iface("dummy0");
+    const std::string prefix("192.0.2.0/24");
+    // First add the downstream, otherwise removeDownstream logic can reasonably
+    // return error for downstreams not previously added.
+    EXPECT_TRUE(mOffload->addDownstream(iface, prefix).isOk());
+    EXPECT_TRUE(mOffload->removeDownstream(iface, prefix).isOk());
+}
+
+// Test removeDownstream() works given an IPv6 prefix.
+TEST_P(TetheroffloadAidlGeneralTest, RemoveDownstreamIPv6) {
+    const std::string iface("dummy0");
+    const std::string prefix("2001:db8::/64");
+    // First add the downstream, otherwise removeDownstream logic can reasonably
+    // return error for downstreams not previously added.
+    EXPECT_TRUE(mOffload->addDownstream(iface, prefix).isOk());
+    EXPECT_TRUE(mOffload->removeDownstream(iface, prefix).isOk());
+}
+
+// Test removeDownstream() fails given all empty parameters.
+TEST_P(TetheroffloadAidlGeneralTest, RemoveDownstreamEmptyFails) {
+    const std::string iface("");
+    const std::string prefix("");
+    EXPECT_EQ(mOffload->removeDownstream(iface, prefix).getExceptionCode(), EX_ILLEGAL_ARGUMENT);
+}
+
+// Test removeDownstream() fails given empty or non-existent interface names.
+TEST_P(TetheroffloadAidlGeneralTest, RemoveDownstreamBogusIfaceFails) {
+    const std::string prefix("192.0.2.0/24");
+    for (const auto& bogus : {"", "invalid"}) {
+        SCOPED_TRACE(testing::Message() << "iface: " << bogus);
+        const std::string iface(bogus);
+        EXPECT_EQ(mOffload->removeDownstream(iface, prefix).getExceptionCode(),
+                  EX_ILLEGAL_ARGUMENT);
+    }
+}
+
+// Test removeDownstream() fails given unparseable prefix arguments.
+TEST_P(TetheroffloadAidlGeneralTest, RemoveDownstreamBogusPrefixFails) {
+    const std::string iface("dummy0");
+    for (const auto& bogus : {"", "192.0.2/24", "2001:db8/64"}) {
+        SCOPED_TRACE(testing::Message() << "prefix: " << bogus);
+        const std::string prefix(bogus);
+        EXPECT_EQ(mOffload->removeDownstream(iface, prefix).getExceptionCode(),
+                  EX_ILLEGAL_ARGUMENT);
+    }
+}
+
+GTEST_ALLOW_UNINSTANTIATED_PARAMETERIZED_TEST(TetheroffloadAidlTestBase);
+INSTANTIATE_TEST_SUITE_P(
+        IOffload, TetheroffloadAidlTestBase,
+        testing::ValuesIn(::android::getAidlHalInstanceNames(IOffload::descriptor)),
+        ::android::PrintInstanceNameToString);
+
+GTEST_ALLOW_UNINSTANTIATED_PARAMETERIZED_TEST(TetheroffloadAidlPreInitTest);
+INSTANTIATE_TEST_SUITE_P(
+        IOffload, TetheroffloadAidlPreInitTest,
+        testing::ValuesIn(::android::getAidlHalInstanceNames(IOffload::descriptor)),
+        ::android::PrintInstanceNameToString);
+
+GTEST_ALLOW_UNINSTANTIATED_PARAMETERIZED_TEST(TetheroffloadAidlGeneralTest);
+INSTANTIATE_TEST_SUITE_P(
+        IOffload, TetheroffloadAidlGeneralTest,
+        testing::ValuesIn(::android::getAidlHalInstanceNames(IOffload::descriptor)),
+        ::android::PrintInstanceNameToString);
+
+}  // namespace
+
+int main(int argc, char** argv) {
+    ::testing::InitGoogleTest(&argc, argv);
+    ABinderProcess_setThreadPoolMaxThreadCount(1);
+    ABinderProcess_startThreadPool();
+    return RUN_ALL_TESTS();
+}
+
+}  // namespace aidl::android::hardware::tetheroffload