diff --git a/Tethering/Android.bp b/Tethering/Android.bp
index 08552cb..596f62f 100644
--- a/Tethering/Android.bp
+++ b/Tethering/Android.bp
@@ -45,9 +45,9 @@
 
 // Due to b/143733063, APK can't access a jni lib that is in APEX (but not in the APK).
 cc_library {
-    name: "libtetheroffloadjni",
+    name: "libtetherutilsjni",
     srcs: [
-        "jni/com_android_server_connectivity_tethering_OffloadHardwareInterface.cpp",
+        "jni/android_net_util_TetheringUtils.cpp",
     ],
     shared_libs: [
         "libcgrouprc",
@@ -87,7 +87,7 @@
         "libcgrouprc",
         "libnativehelper_compat_libc++",
         "libvndksupport",
-        "libtetheroffloadjni",
+        "libtetherutilsjni",
     ],
     resource_dirs: [
         "res",
diff --git a/Tethering/jni/android_net_util_TetheringUtils.cpp b/Tethering/jni/android_net_util_TetheringUtils.cpp
new file mode 100644
index 0000000..1cf8f98
--- /dev/null
+++ b/Tethering/jni/android_net_util_TetheringUtils.cpp
@@ -0,0 +1,256 @@
+/*
+ * 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 <errno.h>
+#include <error.h>
+#include <hidl/HidlSupport.h>
+#include <jni.h>
+#include <nativehelper/JNIHelp.h>
+#include <nativehelper/ScopedUtfChars.h>
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netlink.h>
+#include <net/if.h>
+#include <netinet/icmp6.h>
+#include <sys/socket.h>
+#include <android-base/unique_fd.h>
+#include <android/hardware/tetheroffload/config/1.0/IOffloadConfig.h>
+
+#define LOG_TAG "TetheringUtils"
+#include <utils/Log.h>
+
+namespace android {
+
+using hardware::hidl_handle;
+using hardware::hidl_string;
+using hardware::tetheroffload::config::V1_0::IOffloadConfig;
+
+namespace {
+
+inline const sockaddr * asSockaddr(const sockaddr_nl *nladdr) {
+    return reinterpret_cast<const sockaddr *>(nladdr);
+}
+
+int conntrackSocket(unsigned groups) {
+    base::unique_fd s(socket(AF_NETLINK, SOCK_DGRAM, NETLINK_NETFILTER));
+    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();
+}
+
+// Return a hidl_handle that owns the file descriptor owned by fd, and will
+// auto-close it (otherwise there would be double-close problems).
+//
+// Rely upon the compiler to eliminate the constexprs used for clarity.
+hidl_handle handleFromFileDescriptor(base::unique_fd fd) {
+    hidl_handle h;
+
+    static constexpr int kNumFds = 1;
+    static constexpr int kNumInts = 0;
+    native_handle_t *nh = native_handle_create(kNumFds, kNumInts);
+    nh->data[0] = fd.release();
+
+    static constexpr bool kTakeOwnership = true;
+    h.setTo(nh, kTakeOwnership);
+
+    return h;
+}
+
+}  // namespace
+
+static jboolean android_net_util_configOffload(
+        JNIEnv* /* env */) {
+    sp<IOffloadConfig> configInterface = IOffloadConfig::getService();
+    if (configInterface.get() == nullptr) {
+        ALOGD("Could not find IOffloadConfig service.");
+        return false;
+    }
+
+    // Per the IConfigOffload definition:
+    //
+    // fd1   A file descriptor bound to the following netlink groups
+    //       (NF_NETLINK_CONNTRACK_NEW | NF_NETLINK_CONNTRACK_DESTROY).
+    //
+    // fd2   A file descriptor bound to the following netlink groups
+    //       (NF_NETLINK_CONNTRACK_UPDATE | NF_NETLINK_CONNTRACK_DESTROY).
+    base::unique_fd
+            fd1(conntrackSocket(NF_NETLINK_CONNTRACK_NEW | NF_NETLINK_CONNTRACK_DESTROY)),
+            fd2(conntrackSocket(NF_NETLINK_CONNTRACK_UPDATE | NF_NETLINK_CONNTRACK_DESTROY));
+    if (fd1.get() < 0 || fd2.get() < 0) {
+        ALOGE("Unable to create conntrack handles: %d/%s", errno, strerror(errno));
+        return false;
+    }
+
+    hidl_handle h1(handleFromFileDescriptor(std::move(fd1))),
+                h2(handleFromFileDescriptor(std::move(fd2)));
+
+    bool rval(false);
+    hidl_string msg;
+    const auto status = configInterface->setHandles(h1, h2,
+            [&rval, &msg](bool success, const hidl_string& errMsg) {
+                rval = success;
+                msg = errMsg;
+            });
+    if (!status.isOk() || !rval) {
+        ALOGE("IOffloadConfig::setHandles() error: '%s' / '%s'",
+              status.description().c_str(), msg.c_str());
+        // If status is somehow not ok, make sure rval captures this too.
+        rval = false;
+    }
+
+    return rval;
+}
+
+static void android_net_util_setupRaSocket(JNIEnv *env, jobject clazz, jobject javaFd,
+        jint ifIndex)
+{
+    static const int kLinkLocalHopLimit = 255;
+
+    int fd = jniGetFDFromFileDescriptor(env, javaFd);
+
+    // Set an ICMPv6 filter that only passes Router Solicitations.
+    struct icmp6_filter rs_only;
+    ICMP6_FILTER_SETBLOCKALL(&rs_only);
+    ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT, &rs_only);
+    socklen_t len = sizeof(rs_only);
+    if (setsockopt(fd, IPPROTO_ICMPV6, ICMP6_FILTER, &rs_only, len) != 0) {
+        jniThrowExceptionFmt(env, "java/net/SocketException",
+                "setsockopt(ICMP6_FILTER): %s", strerror(errno));
+        return;
+    }
+
+    // Most/all of the rest of these options can be set via Java code, but
+    // because we're here on account of setting an icmp6_filter go ahead
+    // and do it all natively for now.
+
+    // Set the multicast hoplimit to 255 (link-local only).
+    int hops = kLinkLocalHopLimit;
+    len = sizeof(hops);
+    if (setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &hops, len) != 0) {
+        jniThrowExceptionFmt(env, "java/net/SocketException",
+                "setsockopt(IPV6_MULTICAST_HOPS): %s", strerror(errno));
+        return;
+    }
+
+    // Set the unicast hoplimit to 255 (link-local only).
+    hops = kLinkLocalHopLimit;
+    len = sizeof(hops);
+    if (setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &hops, len) != 0) {
+        jniThrowExceptionFmt(env, "java/net/SocketException",
+                "setsockopt(IPV6_UNICAST_HOPS): %s", strerror(errno));
+        return;
+    }
+
+    // Explicitly disable multicast loopback.
+    int off = 0;
+    len = sizeof(off);
+    if (setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &off, len) != 0) {
+        jniThrowExceptionFmt(env, "java/net/SocketException",
+                "setsockopt(IPV6_MULTICAST_LOOP): %s", strerror(errno));
+        return;
+    }
+
+    // Specify the IPv6 interface to use for outbound multicast.
+    len = sizeof(ifIndex);
+    if (setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_IF, &ifIndex, len) != 0) {
+        jniThrowExceptionFmt(env, "java/net/SocketException",
+                "setsockopt(IPV6_MULTICAST_IF): %s", strerror(errno));
+        return;
+    }
+
+    // Additional options to be considered:
+    //     - IPV6_TCLASS
+    //     - IPV6_RECVPKTINFO
+    //     - IPV6_RECVHOPLIMIT
+
+    // Bind to [::].
+    const struct sockaddr_in6 sin6 = {
+            .sin6_family = AF_INET6,
+            .sin6_port = 0,
+            .sin6_flowinfo = 0,
+            .sin6_addr = IN6ADDR_ANY_INIT,
+            .sin6_scope_id = 0,
+    };
+    auto sa = reinterpret_cast<const struct sockaddr *>(&sin6);
+    len = sizeof(sin6);
+    if (bind(fd, sa, len) != 0) {
+        jniThrowExceptionFmt(env, "java/net/SocketException",
+                "bind(IN6ADDR_ANY): %s", strerror(errno));
+        return;
+    }
+
+    // Join the all-routers multicast group, ff02::2%index.
+    struct ipv6_mreq all_rtrs = {
+        .ipv6mr_multiaddr = {{{0xff,2,0,0,0,0,0,0,0,0,0,0,0,0,0,2}}},
+        .ipv6mr_interface = ifIndex,
+    };
+    len = sizeof(all_rtrs);
+    if (setsockopt(fd, IPPROTO_IPV6, IPV6_JOIN_GROUP, &all_rtrs, len) != 0) {
+        jniThrowExceptionFmt(env, "java/net/SocketException",
+                "setsockopt(IPV6_JOIN_GROUP): %s", strerror(errno));
+        return;
+    }
+}
+
+/*
+ * JNI registration.
+ */
+static const JNINativeMethod gMethods[] = {
+    /* name, signature, funcPtr */
+    { "configOffload", "()Z", (void*) android_net_util_configOffload },
+    { "setupRaSocket", "(Ljava/io/FileDescriptor;I)V", (void*) android_net_util_setupRaSocket },
+};
+
+int register_android_net_util_TetheringUtils(JNIEnv* env) {
+    return jniRegisterNativeMethods(env,
+            "android/net/util/TetheringUtils",
+            gMethods, NELEM(gMethods));
+}
+
+extern "C" jint JNI_OnLoad(JavaVM* vm, void*) {
+    JNIEnv *env;
+    if (vm->GetEnv(reinterpret_cast<void**>(&env), JNI_VERSION_1_6) != JNI_OK) {
+        ALOGE("ERROR: GetEnv failed");
+        return JNI_ERR;
+    }
+
+    if (register_android_net_util_TetheringUtils(env) < 0) {
+        return JNI_ERR;
+    }
+
+    return JNI_VERSION_1_6;
+}
+
+}; // namespace android
diff --git a/Tethering/jni/com_android_server_connectivity_tethering_OffloadHardwareInterface.cpp b/Tethering/jni/com_android_server_connectivity_tethering_OffloadHardwareInterface.cpp
deleted file mode 100644
index 663154a..0000000
--- a/Tethering/jni/com_android_server_connectivity_tethering_OffloadHardwareInterface.cpp
+++ /dev/null
@@ -1,162 +0,0 @@
-/*
- * 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 <errno.h>
-#include <error.h>
-#include <hidl/HidlSupport.h>
-#include <jni.h>
-#include <nativehelper/JNIHelp.h>
-#include <linux/netfilter/nfnetlink.h>
-#include <linux/netlink.h>
-#include <sys/socket.h>
-#include <android-base/unique_fd.h>
-#include <android/hardware/tetheroffload/config/1.0/IOffloadConfig.h>
-
-#define LOG_TAG "OffloadHardwareInterface"
-#include <utils/Log.h>
-
-namespace android {
-
-using hardware::hidl_handle;
-using hardware::hidl_string;
-using hardware::tetheroffload::config::V1_0::IOffloadConfig;
-
-namespace {
-
-inline const sockaddr * asSockaddr(const sockaddr_nl *nladdr) {
-    return reinterpret_cast<const sockaddr *>(nladdr);
-}
-
-int conntrackSocket(unsigned groups) {
-    base::unique_fd s(socket(AF_NETLINK, SOCK_DGRAM, NETLINK_NETFILTER));
-    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();
-}
-
-// Return a hidl_handle that owns the file descriptor owned by fd, and will
-// auto-close it (otherwise there would be double-close problems).
-//
-// Rely upon the compiler to eliminate the constexprs used for clarity.
-hidl_handle handleFromFileDescriptor(base::unique_fd fd) {
-    hidl_handle h;
-
-    static constexpr int kNumFds = 1;
-    static constexpr int kNumInts = 0;
-    native_handle_t *nh = native_handle_create(kNumFds, kNumInts);
-    nh->data[0] = fd.release();
-
-    static constexpr bool kTakeOwnership = true;
-    h.setTo(nh, kTakeOwnership);
-
-    return h;
-}
-
-}  // namespace
-
-static jboolean android_server_connectivity_tethering_OffloadHardwareInterface_configOffload(
-        JNIEnv* /* env */) {
-    sp<IOffloadConfig> configInterface = IOffloadConfig::getService();
-    if (configInterface.get() == nullptr) {
-        ALOGD("Could not find IOffloadConfig service.");
-        return false;
-    }
-
-    // Per the IConfigOffload definition:
-    //
-    // fd1   A file descriptor bound to the following netlink groups
-    //       (NF_NETLINK_CONNTRACK_NEW | NF_NETLINK_CONNTRACK_DESTROY).
-    //
-    // fd2   A file descriptor bound to the following netlink groups
-    //       (NF_NETLINK_CONNTRACK_UPDATE | NF_NETLINK_CONNTRACK_DESTROY).
-    base::unique_fd
-            fd1(conntrackSocket(NF_NETLINK_CONNTRACK_NEW | NF_NETLINK_CONNTRACK_DESTROY)),
-            fd2(conntrackSocket(NF_NETLINK_CONNTRACK_UPDATE | NF_NETLINK_CONNTRACK_DESTROY));
-    if (fd1.get() < 0 || fd2.get() < 0) {
-        ALOGE("Unable to create conntrack handles: %d/%s", errno, strerror(errno));
-        return false;
-    }
-
-    hidl_handle h1(handleFromFileDescriptor(std::move(fd1))),
-                h2(handleFromFileDescriptor(std::move(fd2)));
-
-    bool rval(false);
-    hidl_string msg;
-    const auto status = configInterface->setHandles(h1, h2,
-            [&rval, &msg](bool success, const hidl_string& errMsg) {
-                rval = success;
-                msg = errMsg;
-            });
-    if (!status.isOk() || !rval) {
-        ALOGE("IOffloadConfig::setHandles() error: '%s' / '%s'",
-              status.description().c_str(), msg.c_str());
-        // If status is somehow not ok, make sure rval captures this too.
-        rval = false;
-    }
-
-    return rval;
-}
-
-/*
- * JNI registration.
- */
-static const JNINativeMethod gMethods[] = {
-    /* name, signature, funcPtr */
-    { "configOffload", "()Z",
-      (void*) android_server_connectivity_tethering_OffloadHardwareInterface_configOffload },
-};
-
-int register_android_server_connectivity_tethering_OffloadHardwareInterface(JNIEnv* env) {
-    return jniRegisterNativeMethods(env,
-            "com/android/server/connectivity/tethering/OffloadHardwareInterface",
-            gMethods, NELEM(gMethods));
-}
-
-extern "C" jint JNI_OnLoad(JavaVM* vm, void*) {
-    JNIEnv *env;
-    if (vm->GetEnv(reinterpret_cast<void**>(&env), JNI_VERSION_1_6) != JNI_OK) {
-        ALOGE("ERROR: GetEnv failed");
-        return JNI_ERR;
-    }
-
-    if (register_android_server_connectivity_tethering_OffloadHardwareInterface(env) < 0) {
-        return JNI_ERR;
-    }
-
-    return JNI_VERSION_1_6;
-}
-
-}; // namespace android
diff --git a/Tethering/src/android/net/ip/RouterAdvertisementDaemon.java b/Tethering/src/android/net/ip/RouterAdvertisementDaemon.java
index 4147413..4396cdb 100644
--- a/Tethering/src/android/net/ip/RouterAdvertisementDaemon.java
+++ b/Tethering/src/android/net/ip/RouterAdvertisementDaemon.java
@@ -30,6 +30,7 @@
 import android.net.NetworkUtils;
 import android.net.TrafficStats;
 import android.net.util.InterfaceParams;
+import android.net.util.TetheringUtils;
 import android.system.ErrnoException;
 import android.system.Os;
 import android.system.StructTimeval;
@@ -613,7 +614,7 @@
                     mSocket, SOL_SOCKET, SO_SNDTIMEO, StructTimeval.fromMillis(send_timout_ms));
             Os.setsockoptIfreq(mSocket, SOL_SOCKET, SO_BINDTODEVICE, mInterface.name);
             NetworkUtils.protectFromVpn(mSocket);
-            NetworkUtils.setupRaSocket(mSocket, mInterface.index);
+            TetheringUtils.setupRaSocket(mSocket, mInterface.index);
         } catch (ErrnoException | IOException e) {
             Log.e(TAG, "Failed to create RA daemon socket: " + e);
             return false;
diff --git a/Tethering/src/android/net/util/TetheringUtils.java b/Tethering/src/android/net/util/TetheringUtils.java
new file mode 100644
index 0000000..2fb73ce
--- /dev/null
+++ b/Tethering/src/android/net/util/TetheringUtils.java
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package android.net.util;
+
+import java.io.FileDescriptor;
+import java.net.SocketException;
+
+/**
+ * Native methods for tethering utilization.
+ *
+ * {@hide}
+ */
+public class TetheringUtils {
+
+    /**
+     * Offload management process need to know conntrack rules to support NAT, but it may not have
+     * permission to create netlink netfilter sockets. Create two netlink netfilter sockets and
+     * share them with offload management process.
+     */
+    public static native boolean configOffload();
+
+    /**
+     * Configures a socket for receiving ICMPv6 router solicitations and sending advertisements.
+     * @param fd the socket's {@link FileDescriptor}.
+     * @param ifIndex the interface index.
+     */
+    public static native void setupRaSocket(FileDescriptor fd, int ifIndex)
+            throws SocketException;
+}
diff --git a/Tethering/src/com/android/server/connectivity/tethering/OffloadHardwareInterface.java b/Tethering/src/com/android/server/connectivity/tethering/OffloadHardwareInterface.java
index 00a6773..85164ed 100644
--- a/Tethering/src/com/android/server/connectivity/tethering/OffloadHardwareInterface.java
+++ b/Tethering/src/com/android/server/connectivity/tethering/OffloadHardwareInterface.java
@@ -24,6 +24,7 @@
 import android.hardware.tetheroffload.control.V1_0.NetworkProtocol;
 import android.hardware.tetheroffload.control.V1_0.OffloadCallbackEvent;
 import android.net.util.SharedLog;
+import android.net.util.TetheringUtils;
 import android.os.Handler;
 import android.os.RemoteException;
 import android.system.OsConstants;
@@ -47,8 +48,6 @@
     private static final String NO_IPV4_ADDRESS = "";
     private static final String NO_IPV4_GATEWAY = "";
 
-    private static native boolean configOffload();
-
     private final Handler mHandler;
     private final SharedLog mLog;
     private IOffloadControl mOffloadControl;
@@ -107,8 +106,6 @@
     public OffloadHardwareInterface(Handler h, SharedLog log) {
         mHandler = h;
         mLog = log.forSubComponent(TAG);
-
-        System.loadLibrary("tetheroffloadjni");
     }
 
     /** Get default value indicating whether offload is supported. */
@@ -118,7 +115,7 @@
 
     /** Configure offload management process. */
     public boolean initOffloadConfig() {
-        return configOffload();
+        return TetheringUtils.configOffload();
     }
 
     /** Initialize the tethering offload HAL. */
diff --git a/Tethering/src/com/android/server/connectivity/tethering/TetheringService.java b/Tethering/src/com/android/server/connectivity/tethering/TetheringService.java
index ba30845..1d59986 100644
--- a/Tethering/src/com/android/server/connectivity/tethering/TetheringService.java
+++ b/Tethering/src/com/android/server/connectivity/tethering/TetheringService.java
@@ -84,6 +84,7 @@
      */
     @VisibleForTesting
     public Tethering makeTethering(TetheringDependencies deps) {
+        System.loadLibrary("tetherutilsjni");
         return new Tethering(deps);
     }