diff --git a/staticlibs/Android.bp b/staticlibs/Android.bp
index e0b75c5..2fc4142 100644
--- a/staticlibs/Android.bp
+++ b/staticlibs/Android.bp
@@ -127,7 +127,6 @@
         "//frameworks/libs/net/common/testutils:__subpackages__",
         "//packages/modules/Connectivity:__subpackages__",
         "//packages/modules/NetworkStack:__subpackages__",
-        "//frameworks/base/services/core",
     ],
     libs: [
         "androidx.annotation_annotation",
@@ -260,24 +259,15 @@
     ],
     lint: { strict_updatability_linting: true },
 }
-filegroup {
-    name: "net-utils-services-common-srcs",
+
+java_library {
+    name: "net-utils-services-common",
     srcs: [
         "device/android/net/NetworkFactory.java",
         "device/android/net/NetworkFactoryImpl.java",
         "device/android/net/NetworkFactoryLegacyImpl.java",
         "device/android/net/NetworkFactoryShim.java",
     ],
-    visibility: [
-        "//frameworks/base/services/net",
-    ],
-}
-
-java_library {
-    name: "net-utils-services-common",
-    srcs: [
-        ":net-utils-services-common-srcs",
-    ],
     sdk_version: "module_current",
     min_sdk_version: "30",
     static_libs: [
@@ -292,6 +282,7 @@
         "//apex_available:platform",
         "com.android.bluetooth",
         "com.android.tethering",
+        "com.android.wifi",
     ],
     visibility: [
         // TODO: remove after NetworkStatsService moves to the module.
diff --git a/staticlibs/device/com/android/net/module/util/BpfMap.java b/staticlibs/device/com/android/net/module/util/BpfMap.java
index d4ce83b..f7019a5 100644
--- a/staticlibs/device/com/android/net/module/util/BpfMap.java
+++ b/staticlibs/device/com/android/net/module/util/BpfMap.java
@@ -18,7 +18,9 @@
 import static android.system.OsConstants.EEXIST;
 import static android.system.OsConstants.ENOENT;
 
+import android.os.ParcelFileDescriptor;
 import android.system.ErrnoException;
+import android.util.Pair;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
@@ -26,10 +28,12 @@
 
 import com.android.net.module.util.Struct;
 
+import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.util.NoSuchElementException;
 import java.util.Objects;
+import java.util.concurrent.ConcurrentHashMap;
 
 /**
  * BpfMap is a key -> value mapping structure that is designed to maintained the bpf map entries.
@@ -39,7 +43,7 @@
  * @param <K> the key of the map.
  * @param <V> the value of the map.
  */
-public class BpfMap<K extends Struct, V extends Struct> implements IBpfMap<K, V>, AutoCloseable {
+public class BpfMap<K extends Struct, V extends Struct> implements IBpfMap<K, V> {
     static {
         System.loadLibrary(JniUtil.getJniLibraryName(BpfMap.class.getPackage()));
     }
@@ -57,12 +61,33 @@
     private static final int BPF_NOEXIST = 1;
     private static final int BPF_EXIST = 2;
 
-    private final int mMapFd;
+    private final ParcelFileDescriptor mMapFd;
     private final Class<K> mKeyClass;
     private final Class<V> mValueClass;
     private final int mKeySize;
     private final int mValueSize;
 
+    private static ConcurrentHashMap<Pair<String, Integer>, ParcelFileDescriptor> sFdCache =
+            new ConcurrentHashMap<>();
+
+    private static ParcelFileDescriptor cachedBpfFdGet(String path, int mode)
+            throws ErrnoException, NullPointerException {
+        Pair<String, Integer> key = Pair.create(path, mode);
+        // unlocked fetch is safe: map is concurrent read capable, and only inserted into
+        ParcelFileDescriptor fd = sFdCache.get(key);
+        if (fd != null) return fd;
+        // ok, no cached fd present, need to grab a lock
+        synchronized (BpfMap.class) {
+            // need to redo the check
+            fd = sFdCache.get(key);
+            if (fd != null) return fd;
+            // okay, we really haven't opened this before...
+            fd = ParcelFileDescriptor.adoptFd(nativeBpfFdGet(path, mode));
+            sFdCache.put(key, fd);
+            return fd;
+        }
+    }
+
     /**
      * Create a BpfMap map wrapper with "path" of filesystem.
      *
@@ -72,8 +97,7 @@
      */
     public BpfMap(@NonNull final String path, final int flag, final Class<K> key,
             final Class<V> value) throws ErrnoException, NullPointerException {
-        mMapFd = bpfFdGet(path, flag);
-
+        mMapFd = cachedBpfFdGet(path, flag);
         mKeyClass = key;
         mValueClass = value;
         mKeySize = Struct.getSize(key);
@@ -85,10 +109,11 @@
      * The derived class implements an internal mocked map. It need to implement all functions
      * which are related with the native BPF map because the BPF map handler is not initialized.
      * See BpfCoordinatorTest#TestBpfMap.
+     * TODO: remove once TestBpfMap derive from IBpfMap.
      */
     @VisibleForTesting
     protected BpfMap(final Class<K> key, final Class<V> value) {
-        mMapFd = -1;
+        mMapFd = null;  // unused
         mKeyClass = key;
         mValueClass = value;
         mKeySize = Struct.getSize(key);
@@ -101,7 +126,7 @@
      */
     @Override
     public void updateEntry(K key, V value) throws ErrnoException {
-        writeToMapEntry(mMapFd, key.writeToBytes(), value.writeToBytes(), BPF_ANY);
+        nativeWriteToMapEntry(mMapFd.getFd(), key.writeToBytes(), value.writeToBytes(), BPF_ANY);
     }
 
     /**
@@ -112,7 +137,8 @@
     public void insertEntry(K key, V value)
             throws ErrnoException, IllegalStateException {
         try {
-            writeToMapEntry(mMapFd, key.writeToBytes(), value.writeToBytes(), BPF_NOEXIST);
+            nativeWriteToMapEntry(mMapFd.getFd(), key.writeToBytes(), value.writeToBytes(),
+                    BPF_NOEXIST);
         } catch (ErrnoException e) {
             if (e.errno == EEXIST) throw new IllegalStateException(key + " already exists");
 
@@ -128,7 +154,8 @@
     public void replaceEntry(K key, V value)
             throws ErrnoException, NoSuchElementException {
         try {
-            writeToMapEntry(mMapFd, key.writeToBytes(), value.writeToBytes(), BPF_EXIST);
+            nativeWriteToMapEntry(mMapFd.getFd(), key.writeToBytes(), value.writeToBytes(),
+                    BPF_EXIST);
         } catch (ErrnoException e) {
             if (e.errno == ENOENT) throw new NoSuchElementException(key + " not found");
 
@@ -146,13 +173,15 @@
     public boolean insertOrReplaceEntry(K key, V value)
             throws ErrnoException {
         try {
-            writeToMapEntry(mMapFd, key.writeToBytes(), value.writeToBytes(), BPF_NOEXIST);
+            nativeWriteToMapEntry(mMapFd.getFd(), key.writeToBytes(), value.writeToBytes(),
+                    BPF_NOEXIST);
             return true;   /* insert succeeded */
         } catch (ErrnoException e) {
             if (e.errno != EEXIST) throw e;
         }
         try {
-            writeToMapEntry(mMapFd, key.writeToBytes(), value.writeToBytes(), BPF_EXIST);
+            nativeWriteToMapEntry(mMapFd.getFd(), key.writeToBytes(), value.writeToBytes(),
+                    BPF_EXIST);
             return false;   /* replace succeeded */
         } catch (ErrnoException e) {
             if (e.errno != ENOENT) throw e;
@@ -169,7 +198,7 @@
     /** Remove existing key from eBpf map. Return false if map was not modified. */
     @Override
     public boolean deleteEntry(K key) throws ErrnoException {
-        return deleteMapEntry(mMapFd, key.writeToBytes());
+        return nativeDeleteMapEntry(mMapFd.getFd(), key.writeToBytes());
     }
 
     /** Returns {@code true} if this map contains no elements. */
@@ -202,7 +231,7 @@
 
     private byte[] getNextRawKey(@Nullable final byte[] key) throws ErrnoException {
         byte[] nextKey = new byte[mKeySize];
-        if (getNextMapKey(mMapFd, key, nextKey)) return nextKey;
+        if (nativeGetNextMapKey(mMapFd.getFd(), key, nextKey)) return nextKey;
 
         return null;
     }
@@ -237,7 +266,7 @@
 
     private byte[] getRawValue(final byte[] key) throws ErrnoException {
         byte[] value = new byte[mValueSize];
-        if (findMapEntry(mMapFd, key, value)) return value;
+        if (nativeFindMapEntry(mMapFd.getFd(), key, value)) return value;
 
         return null;
     }
@@ -261,9 +290,13 @@
         }
     }
 
+    /* Empty implementation to implement AutoCloseable, so we can use BpfMaps
+     * with try with resources, but due to persistent FD cache, there is no actual
+     * need to close anything.  File descriptors will actually be closed when we
+     * unlock the BpfMap class and destroy the ParcelFileDescriptor objects.
+     */
     @Override
-    public void close() throws ErrnoException {
-        closeMap(mMapFd);
+    public void close() throws IOException {
     }
 
     /**
@@ -281,19 +314,25 @@
         }
     }
 
-    private static native int closeMap(int fd) throws ErrnoException;
+    private static native int nativeBpfFdGet(String path, int mode)
+            throws ErrnoException, NullPointerException;
 
-    private native int bpfFdGet(String path, int mode) throws ErrnoException, NullPointerException;
+    // Note: the following methods appear to not require the object by virtue of taking the
+    // fd as an int argument, but the hidden reference to this is actually what prevents
+    // the object from being garbage collected (and thus potentially maps closed) prior
+    // to the native code actually running (with a possibly already closed fd).
 
-    private native void writeToMapEntry(int fd, byte[] key, byte[] value, int flags)
+    private native void nativeWriteToMapEntry(int fd, byte[] key, byte[] value, int flags)
             throws ErrnoException;
 
-    private native boolean deleteMapEntry(int fd, byte[] key) throws ErrnoException;
+    private native boolean nativeDeleteMapEntry(int fd, byte[] key) throws ErrnoException;
 
     // If key is found, the operation returns true and the nextKey would reference to the next
     // element.  If key is not found, the operation returns true and the nextKey would reference to
     // the first element.  If key is the last element, false is returned.
-    private native boolean getNextMapKey(int fd, byte[] key, byte[] nextKey) throws ErrnoException;
+    private native boolean nativeGetNextMapKey(int fd, byte[] key, byte[] nextKey)
+            throws ErrnoException;
 
-    private native boolean findMapEntry(int fd, byte[] key, byte[] value) throws ErrnoException;
+    private native boolean nativeFindMapEntry(int fd, byte[] key, byte[] value)
+            throws ErrnoException;
 }
diff --git a/staticlibs/device/com/android/net/module/util/FdEventsReader.java b/staticlibs/device/com/android/net/module/util/FdEventsReader.java
index 71ae13d..4825992 100644
--- a/staticlibs/device/com/android/net/module/util/FdEventsReader.java
+++ b/staticlibs/device/com/android/net/module/util/FdEventsReader.java
@@ -69,6 +69,7 @@
  * @param <BufferType> the type of the buffer used to read data.
  */
 public abstract class FdEventsReader<BufferType> {
+    private static final String TAG = FdEventsReader.class.getSimpleName();
     private static final int FD_EVENTS = EVENT_INPUT | EVENT_ERROR;
     private static final int UNREGISTER_THIS_FD = 0;
 
@@ -167,6 +168,18 @@
     protected void handlePacket(@NonNull BufferType recvbuf, int length) {}
 
     /**
+     * Called by the subclasses of FdEventsReader, decide whether it should stop reading packet or
+     * just ignore the specific error other than EAGAIN or EINTR.
+     *
+     * @return {@code true} if this FdEventsReader should stop reading from the socket.
+     *         {@code false} if it should continue.
+     */
+    protected boolean handleReadError(@NonNull ErrnoException e) {
+        logError("readPacket error: ", e);
+        return true; // by default, stop reading on any error.
+    }
+
+    /**
      * Called by the main loop to log errors.  In some cases |e| may be null.
      */
     protected void logError(@NonNull String msg, @Nullable Exception e) {}
@@ -211,7 +224,7 @@
         return true;
     }
 
-    private boolean isRunning() {
+    protected boolean isRunning() {
         return (mFd != null) && mFd.valid();
     }
 
@@ -234,8 +247,10 @@
                 } else if (e.errno == OsConstants.EINTR) {
                     continue;
                 } else {
-                    if (isRunning()) logError("readPacket error: ", e);
-                    break;
+                    if (!isRunning()) break;
+                    final boolean shouldStop = handleReadError(e);
+                    if (shouldStop) break;
+                    continue;
                 }
             } catch (Exception e) {
                 if (isRunning()) logError("readPacket error: ", e);
@@ -246,7 +261,7 @@
                 handlePacket(mBuffer, bytesRead);
             } catch (Exception e) {
                 logError("handlePacket error: ", e);
-                Log.wtf(FdEventsReader.class.getSimpleName(), "Error handling packet", e);
+                Log.wtf(TAG, "Error handling packet", e);
             }
         }
 
diff --git a/staticlibs/device/com/android/net/module/util/IBpfMap.java b/staticlibs/device/com/android/net/module/util/IBpfMap.java
index d43b22c..dce369a 100644
--- a/staticlibs/device/com/android/net/module/util/IBpfMap.java
+++ b/staticlibs/device/com/android/net/module/util/IBpfMap.java
@@ -20,7 +20,6 @@
 import androidx.annotation.NonNull;
 
 import java.util.NoSuchElementException;
-import java.util.function.BiConsumer;
 
 /**
  * The interface of BpfMap. This could be used to inject for testing.
@@ -29,7 +28,7 @@
  * @param <K> the key of the map.
  * @param <V> the value of the map.
  */
-public interface IBpfMap<K extends Struct, V extends Struct> {
+public interface IBpfMap<K extends Struct, V extends Struct> extends AutoCloseable {
     /** Update an existing or create a new key -> value entry in an eBbpf map. */
     void updateEntry(K key, V value) throws ErrnoException;
 
diff --git a/staticlibs/device/com/android/net/module/util/Ipv6Utils.java b/staticlibs/device/com/android/net/module/util/Ipv6Utils.java
index fe7c89b..d538221 100644
--- a/staticlibs/device/com/android/net/module/util/Ipv6Utils.java
+++ b/staticlibs/device/com/android/net/module/util/Ipv6Utils.java
@@ -20,6 +20,7 @@
 
 import static com.android.net.module.util.IpUtils.icmpv6Checksum;
 import static com.android.net.module.util.NetworkStackConstants.ETHER_TYPE_IPV6;
+import static com.android.net.module.util.NetworkStackConstants.ICMPV6_ECHO_REPLY_TYPE;
 import static com.android.net.module.util.NetworkStackConstants.ICMPV6_ECHO_REQUEST_TYPE;
 import static com.android.net.module.util.NetworkStackConstants.ICMPV6_NEIGHBOR_ADVERTISEMENT;
 import static com.android.net.module.util.NetworkStackConstants.ICMPV6_NEIGHBOR_SOLICITATION;
@@ -45,29 +46,23 @@
  */
 public class Ipv6Utils {
     /**
-     * Build a generic ICMPv6 packet(e.g., packet used in the neighbor discovery protocol).
+     * Build a generic ICMPv6 packet without Ethernet header.
      */
-    public static ByteBuffer buildIcmpv6Packet(final MacAddress srcMac, final MacAddress dstMac,
-            final Inet6Address srcIp, final Inet6Address dstIp, short type, short code,
-            final ByteBuffer... options) {
-        final int etherHeaderLen = Struct.getSize(EthernetHeader.class);
+    public static ByteBuffer buildIcmpv6Packet(final Inet6Address srcIp, final Inet6Address dstIp,
+            short type, short code, final ByteBuffer... options) {
         final int ipv6HeaderLen = Struct.getSize(Ipv6Header.class);
         final int icmpv6HeaderLen = Struct.getSize(Icmpv6Header.class);
         int payloadLen = 0;
         for (ByteBuffer option: options) {
             payloadLen += option.limit();
         }
-        final ByteBuffer packet = ByteBuffer.allocate(etherHeaderLen + ipv6HeaderLen
-                + icmpv6HeaderLen + payloadLen);
-        final EthernetHeader ethHeader =
-                new EthernetHeader(dstMac, srcMac, (short) ETHER_TYPE_IPV6);
+        final ByteBuffer packet = ByteBuffer.allocate(ipv6HeaderLen + icmpv6HeaderLen + payloadLen);
         final Ipv6Header ipv6Header =
                 new Ipv6Header((int) 0x60000000 /* version, traffic class, flowlabel */,
                 icmpv6HeaderLen + payloadLen /* payload length */,
                 (byte) IPPROTO_ICMPV6 /* next header */, (byte) 0xff /* hop limit */, srcIp, dstIp);
         final Icmpv6Header icmpv6Header = new Icmpv6Header(type, code, (short) 0 /* checksum */);
 
-        ethHeader.writeToByteBuffer(packet);
         ipv6Header.writeToByteBuffer(packet);
         icmpv6Header.writeToByteBuffer(packet);
         for (ByteBuffer option : options) {
@@ -79,11 +74,31 @@
         packet.flip();
 
         // Populate the ICMPv6 checksum field.
-        packet.putShort(etherHeaderLen + ipv6HeaderLen + 2, icmpv6Checksum(packet,
-                etherHeaderLen /* ipOffset */,
-                (int) (etherHeaderLen + ipv6HeaderLen) /* transportOffset */,
+        packet.putShort(ipv6HeaderLen + 2, icmpv6Checksum(packet, 0 /* ipOffset */,
+                ipv6HeaderLen /* transportOffset */,
                 (short) (icmpv6HeaderLen + payloadLen) /* transportLen */));
         return packet;
+
+    }
+
+    /**
+     * Build a generic ICMPv6 packet(e.g., packet used in the neighbor discovery protocol).
+     */
+    public static ByteBuffer buildIcmpv6Packet(final MacAddress srcMac, final MacAddress dstMac,
+            final Inet6Address srcIp, final Inet6Address dstIp, short type, short code,
+            final ByteBuffer... options) {
+        final ByteBuffer payload = buildIcmpv6Packet(srcIp, dstIp, type, code, options);
+
+        final int etherHeaderLen = Struct.getSize(EthernetHeader.class);
+        final ByteBuffer packet = ByteBuffer.allocate(etherHeaderLen + payload.limit());
+        final EthernetHeader ethHeader =
+                new EthernetHeader(dstMac, srcMac, (short) ETHER_TYPE_IPV6);
+
+        ethHeader.writeToByteBuffer(packet);
+        packet.put(payload);
+        packet.flip();
+
+        return packet;
     }
 
     /**
@@ -159,4 +174,14 @@
         return buildIcmpv6Packet(srcMac, dstMac, srcIp, dstIp,
                 (byte) ICMPV6_ECHO_REQUEST_TYPE /* type */, (byte) 0 /* code */, payload);
     }
+
+    /**
+     * Build an ICMPv6 Echo Reply packet without ethernet header.
+     */
+    public static ByteBuffer buildEchoReplyPacket(final Inet6Address srcIp,
+            final Inet6Address dstIp) {
+        final ByteBuffer payload = ByteBuffer.allocate(4); // ID and Sequence number may be zero.
+        return buildIcmpv6Packet(srcIp, dstIp, (byte) ICMPV6_ECHO_REPLY_TYPE /* type */,
+                (byte) 0 /* code */, payload);
+    }
 }
diff --git a/staticlibs/device/com/android/net/module/util/PacketBuilder.java b/staticlibs/device/com/android/net/module/util/PacketBuilder.java
index c908528..33e5bfa 100644
--- a/staticlibs/device/com/android/net/module/util/PacketBuilder.java
+++ b/staticlibs/device/com/android/net/module/util/PacketBuilder.java
@@ -17,6 +17,7 @@
 package com.android.net.module.util;
 
 import static android.system.OsConstants.IPPROTO_IP;
+import static android.system.OsConstants.IPPROTO_IPV6;
 import static android.system.OsConstants.IPPROTO_TCP;
 import static android.system.OsConstants.IPPROTO_UDP;
 
@@ -25,6 +26,8 @@
 import static com.android.net.module.util.IpUtils.udpChecksum;
 import static com.android.net.module.util.NetworkStackConstants.IPV4_CHECKSUM_OFFSET;
 import static com.android.net.module.util.NetworkStackConstants.IPV4_LENGTH_OFFSET;
+import static com.android.net.module.util.NetworkStackConstants.IPV6_HEADER_LEN;
+import static com.android.net.module.util.NetworkStackConstants.IPV6_LEN_OFFSET;
 import static com.android.net.module.util.NetworkStackConstants.TCP_CHECKSUM_OFFSET;
 import static com.android.net.module.util.NetworkStackConstants.UDP_CHECKSUM_OFFSET;
 import static com.android.net.module.util.NetworkStackConstants.UDP_LENGTH_OFFSET;
@@ -35,11 +38,13 @@
 
 import com.android.net.module.util.structs.EthernetHeader;
 import com.android.net.module.util.structs.Ipv4Header;
+import com.android.net.module.util.structs.Ipv6Header;
 import com.android.net.module.util.structs.TcpHeader;
 import com.android.net.module.util.structs.UdpHeader;
 
 import java.io.IOException;
 import java.net.Inet4Address;
+import java.net.Inet6Address;
 import java.nio.BufferOverflowException;
 import java.nio.ByteBuffer;
 
@@ -49,7 +54,7 @@
  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  * |                Layer 2 header (EthernetHeader)                | (optional)
  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
- * |                  Layer 3 header (Ipv4Header)                  |
+ * |           Layer 3 header (Ipv4Header, Ipv6Header)             |
  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  * |           Layer 4 header (TcpHeader, UdpHeader)               |
  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
@@ -74,11 +79,14 @@
  * sendPacket(buf);
  */
 public class PacketBuilder {
+    private static final int INVALID_OFFSET = -1;
+
     private final ByteBuffer mBuffer;
 
-    private int mIpv4HeaderOffset = -1;
-    private int mTcpHeaderOffset = -1;
-    private int mUdpHeaderOffset = -1;
+    private int mIpv4HeaderOffset = INVALID_OFFSET;
+    private int mIpv6HeaderOffset = INVALID_OFFSET;
+    private int mTcpHeaderOffset = INVALID_OFFSET;
+    private int mUdpHeaderOffset = INVALID_OFFSET;
 
     public PacketBuilder(@NonNull ByteBuffer buffer) {
         mBuffer = buffer;
@@ -93,9 +101,9 @@
      */
     public void writeL2Header(MacAddress srcMac, MacAddress dstMac, short etherType) throws
             IOException {
-        final EthernetHeader ethv4Header = new EthernetHeader(dstMac, srcMac, etherType);
+        final EthernetHeader ethHeader = new EthernetHeader(dstMac, srcMac, etherType);
         try {
-            ethv4Header.writeToByteBuffer(mBuffer);
+            ethHeader.writeToByteBuffer(mBuffer);
         } catch (IllegalArgumentException | BufferOverflowException e) {
             throw new IOException("Error writing to buffer: ", e);
         }
@@ -130,6 +138,31 @@
     }
 
     /**
+     * Write an IPv6 header.
+     * The IP header length is calculated and written back in #finalizePacket.
+     *
+     * @param vtf version, traffic class and flow label
+     * @param nextHeader the transport layer protocol
+     * @param hopLimit hop limit
+     * @param srcIp source IP address
+     * @param dstIp destination IP address
+     */
+    public void writeIpv6Header(int vtf, byte nextHeader, short hopLimit,
+            @NonNull final Inet6Address srcIp, @NonNull final Inet6Address dstIp)
+            throws IOException {
+        mIpv6HeaderOffset = mBuffer.position();
+        final Ipv6Header ipv6Header = new Ipv6Header(vtf,
+                (short) 0 /* payloadLength, calculate in #finalizePacket */, nextHeader,
+                hopLimit, srcIp, dstIp);
+
+        try {
+            ipv6Header.writeToByteBuffer(mBuffer);
+        } catch (IllegalArgumentException | BufferOverflowException e) {
+            throw new IOException("Error writing to buffer: ", e);
+        }
+    }
+
+    /**
      * Write a TCP header.
      * The TCP header checksum is calculated and written back in #finalizePacket.
      *
@@ -186,32 +219,43 @@
      */
     @NonNull
     public ByteBuffer finalizePacket() throws IOException {
-        if (mIpv4HeaderOffset < 0) {
-            // TODO: add support for IPv6
-            throw new IOException("Packet is missing IPv4 header");
+        // [1] Finalize IPv4 or IPv6 header.
+        int ipHeaderOffset = INVALID_OFFSET;
+        if (mIpv4HeaderOffset != INVALID_OFFSET) {
+            ipHeaderOffset = mIpv4HeaderOffset;
+
+            // Populate the IPv4 totalLength field.
+            mBuffer.putShort(mIpv4HeaderOffset + IPV4_LENGTH_OFFSET,
+                    (short) (mBuffer.position() - mIpv4HeaderOffset));
+
+            // Populate the IPv4 header checksum field.
+            mBuffer.putShort(mIpv4HeaderOffset + IPV4_CHECKSUM_OFFSET,
+                    ipChecksum(mBuffer, mIpv4HeaderOffset /* headerOffset */));
+        } else if (mIpv6HeaderOffset != INVALID_OFFSET) {
+            ipHeaderOffset = mIpv6HeaderOffset;
+
+            // Populate the IPv6 payloadLength field.
+            // The payload length doesn't include IPv6 header length. See rfc8200 section 3.
+            mBuffer.putShort(mIpv6HeaderOffset + IPV6_LEN_OFFSET,
+                    (short) (mBuffer.position() - mIpv6HeaderOffset - IPV6_HEADER_LEN));
+        } else {
+            throw new IOException("Packet is missing neither IPv4 nor IPv6 header");
         }
 
-        // Populate the IPv4 totalLength field.
-        mBuffer.putShort(mIpv4HeaderOffset + IPV4_LENGTH_OFFSET,
-                (short) (mBuffer.position() - mIpv4HeaderOffset));
-
-        // Populate the IPv4 header checksum field.
-        mBuffer.putShort(mIpv4HeaderOffset + IPV4_CHECKSUM_OFFSET,
-                ipChecksum(mBuffer, mIpv4HeaderOffset /* headerOffset */));
-
-        if (mTcpHeaderOffset > 0) {
+        // [2] Finalize TCP or UDP header.
+        if (mTcpHeaderOffset != INVALID_OFFSET) {
             // Populate the TCP header checksum field.
             mBuffer.putShort(mTcpHeaderOffset + TCP_CHECKSUM_OFFSET, tcpChecksum(mBuffer,
-                    mIpv4HeaderOffset /* ipOffset */, mTcpHeaderOffset /* transportOffset */,
+                    ipHeaderOffset /* ipOffset */, mTcpHeaderOffset /* transportOffset */,
                     mBuffer.position() - mTcpHeaderOffset /* transportLen */));
-        } else if (mUdpHeaderOffset > 0) {
+        } else if (mUdpHeaderOffset != INVALID_OFFSET) {
             // Populate the UDP header length field.
             mBuffer.putShort(mUdpHeaderOffset + UDP_LENGTH_OFFSET,
                     (short) (mBuffer.position() - mUdpHeaderOffset));
 
             // Populate the UDP header checksum field.
             mBuffer.putShort(mUdpHeaderOffset + UDP_CHECKSUM_OFFSET, udpChecksum(mBuffer,
-                    mIpv4HeaderOffset /* ipOffset */, mUdpHeaderOffset /* transportOffset */));
+                    ipHeaderOffset /* ipOffset */, mUdpHeaderOffset /* transportOffset */));
         } else {
             throw new IOException("Packet is missing neither TCP nor UDP header");
         }
@@ -225,15 +269,15 @@
      *
      * @param hasEther has ethernet header. Set this flag to indicate that the packet has an
      *        ethernet header.
-     * @param l3proto the layer 3 protocol. Only {@code IPPROTO_IP} currently supported.
+     * @param l3proto the layer 3 protocol. Only {@code IPPROTO_IP} and {@code IPPROTO_IPV6}
+     *        currently supported.
      * @param l4proto the layer 4 protocol. Only {@code IPPROTO_TCP} and {@code IPPROTO_UDP}
      *        currently supported.
      * @param payloadLen length of the payload.
      */
     @NonNull
     public static ByteBuffer allocate(boolean hasEther, int l3proto, int l4proto, int payloadLen) {
-        if (l3proto != IPPROTO_IP) {
-            // TODO: add support for IPv6
+        if (l3proto != IPPROTO_IP && l3proto != IPPROTO_IPV6) {
             throw new IllegalArgumentException("Unsupported layer 3 protocol " + l3proto);
         }
 
@@ -247,7 +291,8 @@
 
         int packetLen = 0;
         if (hasEther) packetLen += Struct.getSize(EthernetHeader.class);
-        packetLen += Struct.getSize(Ipv4Header.class);
+        packetLen += (l3proto == IPPROTO_IP) ? Struct.getSize(Ipv4Header.class)
+                : Struct.getSize(Ipv6Header.class);
         packetLen += (l4proto == IPPROTO_TCP) ? Struct.getSize(TcpHeader.class)
                 : Struct.getSize(UdpHeader.class);
         packetLen += payloadLen;
diff --git a/staticlibs/device/com/android/net/module/util/netlink/NetlinkMessage.java b/staticlibs/device/com/android/net/module/util/netlink/NetlinkMessage.java
index a216752..9e1e26e 100644
--- a/staticlibs/device/com/android/net/module/util/netlink/NetlinkMessage.java
+++ b/staticlibs/device/com/android/net/module/util/netlink/NetlinkMessage.java
@@ -51,8 +51,8 @@
             return null;
         }
 
-        int payloadLength = NetlinkConstants.alignedLengthOf(nlmsghdr.nlmsg_len);
-        payloadLength -= StructNlMsgHdr.STRUCT_SIZE;
+        final int messageLength = NetlinkConstants.alignedLengthOf(nlmsghdr.nlmsg_len);
+        final int payloadLength = messageLength - StructNlMsgHdr.STRUCT_SIZE;
         if (payloadLength < 0 || payloadLength > byteBuffer.remaining()) {
             // Malformed message or runt buffer.  Pretend the buffer was consumed.
             byteBuffer.position(byteBuffer.limit());
@@ -68,15 +68,22 @@
         // Netlink family messages. The netlink family is required. Note that the reason for using
         // if-statement is that switch-case can't be used because the OsConstants.NETLINK_* are
         // not constant.
+        final NetlinkMessage parsed;
         if (nlFamily == OsConstants.NETLINK_ROUTE) {
-            return parseRtMessage(nlmsghdr, byteBuffer);
+            parsed = parseRtMessage(nlmsghdr, byteBuffer);
         } else if (nlFamily == OsConstants.NETLINK_INET_DIAG) {
-            return parseInetDiagMessage(nlmsghdr, byteBuffer);
+            parsed = parseInetDiagMessage(nlmsghdr, byteBuffer);
         } else if (nlFamily == OsConstants.NETLINK_NETFILTER) {
-            return parseNfMessage(nlmsghdr, byteBuffer);
+            parsed = parseNfMessage(nlmsghdr, byteBuffer);
+        } else {
+            parsed = null;
         }
 
-        return null;
+        // Advance to the end of the message, regardless of whether the parsing code consumed
+        // all of it or not.
+        byteBuffer.position(startPosition + messageLength);
+
+        return parsed;
     }
 
     @NonNull
diff --git a/staticlibs/framework/com/android/net/module/util/PerUidCounter.java b/staticlibs/framework/com/android/net/module/util/PerUidCounter.java
new file mode 100644
index 0000000..0b2de7a
--- /dev/null
+++ b/staticlibs/framework/com/android/net/module/util/PerUidCounter.java
@@ -0,0 +1,103 @@
+/*
+ * 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.
+ */
+
+package com.android.net.module.util;
+
+import android.util.SparseIntArray;
+
+import com.android.internal.annotations.GuardedBy;
+import com.android.internal.annotations.VisibleForTesting;
+
+/**
+ * Keeps track of the counters under different uid, fire exception if the counter
+ * exceeded the specified maximum value.
+ *
+ * @hide
+ */
+public class PerUidCounter {
+    private final int mMaxCountPerUid;
+
+    // Map from UID to count that UID has filed.
+    @VisibleForTesting
+    @GuardedBy("mUidToCount")
+    final SparseIntArray mUidToCount = new SparseIntArray();
+
+    /**
+     * Constructor
+     *
+     * @param maxCountPerUid the maximum count per uid allowed
+     */
+    public PerUidCounter(final int maxCountPerUid) {
+        if (maxCountPerUid <= 0) {
+            throw new IllegalArgumentException("Maximum counter value must be positive");
+        }
+        mMaxCountPerUid = maxCountPerUid;
+    }
+
+    /**
+     * Increments the count of the given uid.  Throws an exception if the number
+     * of the counter for the uid exceeds the value of maxCounterPerUid which is the value
+     * passed into the constructor. see: {@link #PerUidCounter(int)}.
+     *
+     * @throws IllegalStateException if the number of counter for the uid exceed
+     *         the allowed number.
+     *
+     * @param uid the uid that the counter was made under
+     */
+    public void incrementCountOrThrow(final int uid) {
+        incrementCountOrThrow(uid, 1 /* numToIncrement */);
+    }
+
+    public synchronized void incrementCountOrThrow(final int uid, final int numToIncrement) {
+        if (numToIncrement <= 0) {
+            throw new IllegalArgumentException("Increment count must be positive");
+        }
+        final long newCount = ((long) mUidToCount.get(uid, 0)) + numToIncrement;
+        if (newCount > mMaxCountPerUid) {
+            throw new IllegalStateException("Uid " + uid + " exceeded its allowed limit");
+        }
+        // Since the count cannot be greater than Integer.MAX_VALUE here since mMaxCountPerUid
+        // is an integer, it is safe to cast to int.
+        mUidToCount.put(uid, (int) newCount);
+    }
+
+    /**
+     * Decrements the count of the given uid. Throws an exception if the number
+     * of the counter goes below zero.
+     *
+     * @throws IllegalStateException if the number of counter for the uid goes below
+     *         zero.
+     *
+     * @param uid the uid that the count was made under
+     */
+    public void decrementCountOrThrow(final int uid) {
+        decrementCountOrThrow(uid, 1 /* numToDecrement */);
+    }
+
+    public synchronized void decrementCountOrThrow(final int uid, final int numToDecrement) {
+        if (numToDecrement <= 0) {
+            throw new IllegalArgumentException("Decrement count must be positive");
+        }
+        final int newCount = mUidToCount.get(uid, 0) - numToDecrement;
+        if (newCount < 0) {
+            throw new IllegalStateException("BUG: too small count " + newCount + " for UID " + uid);
+        } else if (newCount == 0) {
+            mUidToCount.delete(uid);
+        } else {
+            mUidToCount.put(uid, newCount);
+        }
+    }
+}
diff --git a/staticlibs/native/bpf_headers/include/bpf/BpfMap.h b/staticlibs/native/bpf_headers/include/bpf/BpfMap.h
index bdffc0f..a7720ea 100644
--- a/staticlibs/native/bpf_headers/include/bpf/BpfMap.h
+++ b/staticlibs/native/bpf_headers/include/bpf/BpfMap.h
@@ -49,16 +49,20 @@
   protected:
     // flag must be within BPF_OBJ_FLAG_MASK, ie. 0, BPF_F_RDONLY, BPF_F_WRONLY
     BpfMap<Key, Value>(const char* pathname, uint32_t flags) {
-        int map_fd = mapRetrieve(pathname, flags);
-        if (map_fd >= 0) mMapFd.reset(map_fd);
+        mMapFd.reset(mapRetrieve(pathname, flags));
+        if (mMapFd < 0) abort();
+        if (isAtLeastKernelVersion(4, 14, 0)) {
+            if (bpfGetFdKeySize(mMapFd) != sizeof(Key)) abort();
+            if (bpfGetFdValueSize(mMapFd) != sizeof(Value)) abort();
+        }
     }
 
   public:
     explicit BpfMap<Key, Value>(const char* pathname) : BpfMap<Key, Value>(pathname, 0) {}
 
     BpfMap<Key, Value>(bpf_map_type map_type, uint32_t max_entries, uint32_t map_flags = 0) {
-        int map_fd = createMap(map_type, sizeof(Key), sizeof(Value), max_entries, map_flags);
-        if (map_fd >= 0) mMapFd.reset(map_fd);
+        mMapFd.reset(createMap(map_type, sizeof(Key), sizeof(Value), max_entries, map_flags));
+        if (mMapFd < 0) abort();
     }
 
     base::Result<Key> getFirstKey() const {
@@ -100,7 +104,26 @@
     }
 
     // Function that tries to get map from a pinned path.
-    base::Result<void> init(const char* path);
+    [[clang::reinitializes]] base::Result<void> init(const char* path);
+
+#ifdef TEST_BPF_MAP
+    // due to Android SELinux limitations which prevent map creation by anyone besides the bpfloader
+    // this should only ever be used by test code, it is equivalent to:
+    //   .reset(createMap(type, keysize, valuesize, max_entries, map_flags)
+    // TODO: derive map_flags from BpfMap vs BpfMapRO
+    [[clang::reinitializes]] base::Result<void> resetMap(bpf_map_type map_type,
+                                                         uint32_t max_entries,
+                                                         uint32_t map_flags = 0) {
+        int map_fd = createMap(map_type, sizeof(Key), sizeof(Value), max_entries, map_flags);
+        if (map_fd < 0) {
+             auto err = ErrnoErrorf("Unable to create map.");
+             mMapFd.reset();
+             return err;
+        };
+        mMapFd.reset(map_fd);
+        return {};
+    }
+#endif
 
     // Iterate through the map and handle each key retrieved based on the filter
     // without modification of map content.
@@ -135,14 +158,23 @@
 
     // Move assignment operator
     BpfMap<Key, Value>& operator=(BpfMap<Key, Value>&& other) noexcept {
-        mMapFd = std::move(other.mMapFd);
-        other.reset(-1);
+        if (this != &other) {
+            mMapFd = std::move(other.mMapFd);
+            other.reset();
+        }
         return *this;
     }
 
     void reset(base::unique_fd fd) = delete;
 
-    void reset(int fd) { mMapFd.reset(fd); }
+    [[clang::reinitializes]] void reset(int fd = -1) {
+        mMapFd.reset(fd);
+        if ((fd >= 0) && isAtLeastKernelVersion(4, 14, 0)) {
+            if (bpfGetFdKeySize(mMapFd) != sizeof(Key)) abort();
+            if (bpfGetFdValueSize(mMapFd) != sizeof(Value)) abort();
+            if (bpfGetFdMapFlags(mMapFd) != 0) abort(); // TODO: fix for BpfMapRO
+        }
+    }
 
     bool isValid() const { return mMapFd != -1; }
 
@@ -179,10 +211,18 @@
 
 template <class Key, class Value>
 base::Result<void> BpfMap<Key, Value>::init(const char* path) {
-    mMapFd = base::unique_fd(mapRetrieveRW(path));
+    mMapFd.reset(mapRetrieveRW(path));
     if (mMapFd == -1) {
         return ErrnoErrorf("Pinned map not accessible or does not exist: ({})", path);
     }
+    if (isAtLeastKernelVersion(4, 14, 0)) {
+        // Normally we should return an error here instead of calling abort,
+        // but this cannot happen at runtime without a massive code bug (K/V type mismatch)
+        // and as such it's better to just blow the system up and let the developer fix it.
+        // Crashes are much more likely to be noticed than logs and missing functionality.
+        if (bpfGetFdKeySize(mMapFd) != sizeof(Key)) abort();
+        if (bpfGetFdValueSize(mMapFd) != sizeof(Value)) abort();
+    }
     return {};
 }
 
diff --git a/staticlibs/native/bpf_headers/include/bpf/BpfUtils.h b/staticlibs/native/bpf_headers/include/bpf/BpfUtils.h
index 8f1b9a2..4429164 100644
--- a/staticlibs/native/bpf_headers/include/bpf/BpfUtils.h
+++ b/staticlibs/native/bpf_headers/include/bpf/BpfUtils.h
@@ -60,6 +60,9 @@
     // This is a temporary hack for network stats map swap on devices running
     // 4.9 kernels. The kernel code of socket release on pf_key socket will
     // explicitly call synchronize_rcu() which is exactly what we need.
+    //
+    // Linux 4.14/4.19/5.4/5.10/5.15 (and 5.18) still have this same behaviour.
+    // see net/key/af_key.c: pfkey_release() -> synchronize_rcu()
     int pfSocket = socket(AF_KEY, SOCK_RAW | SOCK_CLOEXEC, PF_KEY_V2);
 
     if (pfSocket < 0) {
@@ -92,22 +95,22 @@
 
 #define KVER(a, b, c) (((a) << 24) + ((b) << 16) + (c))
 
-static inline unsigned kernelVersion() {
+static inline unsigned uncachedKernelVersion() {
     struct utsname buf;
-    int ret = uname(&buf);
-    if (ret) return 0;
+    if (uname(&buf)) return 0;
 
-    unsigned kver_major;
-    unsigned kver_minor;
-    unsigned kver_sub;
-    char unused;
-    ret = sscanf(buf.release, "%u.%u.%u%c", &kver_major, &kver_minor, &kver_sub, &unused);
-    // Check the device kernel version
-    if (ret < 3) return 0;
-
+    unsigned kver_major = 0;
+    unsigned kver_minor = 0;
+    unsigned kver_sub = 0;
+    (void)sscanf(buf.release, "%u.%u.%u", &kver_major, &kver_minor, &kver_sub);
     return KVER(kver_major, kver_minor, kver_sub);
 }
 
+static inline unsigned kernelVersion() {
+    static unsigned kver = uncachedKernelVersion();
+    return kver;
+}
+
 static inline bool isAtLeastKernelVersion(unsigned major, unsigned minor, unsigned sub) {
     return kernelVersion() >= KVER(major, minor, sub);
 }
diff --git a/staticlibs/native/bpf_headers/include/bpf/bpf_helpers.h b/staticlibs/native/bpf_headers/include/bpf/bpf_helpers.h
index ac9f9bc..4b035b9 100644
--- a/staticlibs/native/bpf_headers/include/bpf/bpf_helpers.h
+++ b/staticlibs/native/bpf_headers/include/bpf/bpf_helpers.h
@@ -19,6 +19,17 @@
  *                                                                            *
  ******************************************************************************/
 
+// The actual versions of the bpfloader that shipped in various Android releases
+
+// Android P/Q/R: BpfLoader was initially part of netd,
+// this was later split out into a standalone binary, but was unversioned.
+
+// Android S / 12 (api level 31) - added 'tethering' mainline eBPF support
+#define BPFLOADER_S_VERSION 2u
+
+// Android T / 13 Beta 3 (api level 33) - added support for 'netd_shared'
+#define BPFLOADER_T_BETA3_VERSION 13u
+
 /* For mainline module use, you can #define BPFLOADER_{MIN/MAX}_VER
  * before #include "bpf_helpers.h" to change which bpfloaders will
  * process the resulting .o file.
@@ -177,6 +188,8 @@
 static unsigned long long (*bpf_get_current_pid_tgid)(void) = (void*) BPF_FUNC_get_current_pid_tgid;
 static unsigned long long (*bpf_get_current_uid_gid)(void) = (void*) BPF_FUNC_get_current_uid_gid;
 static unsigned long long (*bpf_get_smp_processor_id)(void) = (void*) BPF_FUNC_get_smp_processor_id;
+static long (*bpf_get_stackid)(void* ctx, void* map, uint64_t flags) = (void*) BPF_FUNC_get_stackid;
+static long (*bpf_get_current_comm)(void* buf, uint32_t buf_size) = (void*) BPF_FUNC_get_current_comm;
 
 #define DEFINE_BPF_PROG_KVER_RANGE_OPT(SECTION_NAME, prog_uid, prog_gid, the_prog, min_kv, max_kv, \
                                        opt)                                                        \
diff --git a/staticlibs/native/bpf_syscall_wrappers/include/BpfSyscallWrappers.h b/staticlibs/native/bpf_syscall_wrappers/include/BpfSyscallWrappers.h
index abf83da..4b29c44 100644
--- a/staticlibs/native/bpf_syscall_wrappers/include/BpfSyscallWrappers.h
+++ b/staticlibs/native/bpf_syscall_wrappers/include/BpfSyscallWrappers.h
@@ -150,6 +150,36 @@
                                 });
 }
 
+// requires 4.14+ kernel
+
+#define DEFINE_BPF_GET_FD_INFO(NAME, FIELD) \
+inline int bpfGetFd ## NAME(const BPF_FD_TYPE map_fd) { \
+    struct bpf_map_info map_info = {}; \
+    union bpf_attr attr = { .info = { \
+        .bpf_fd = BPF_FD_TO_U32(map_fd), \
+        .info_len = sizeof(map_info), \
+        .info = ptr_to_u64(&map_info), \
+    }}; \
+    int rv = bpf(BPF_OBJ_GET_INFO_BY_FD, attr); \
+    if (rv) return rv; \
+    if (attr.info.info_len < offsetof(bpf_map_info, FIELD) + sizeof(map_info.FIELD)) { \
+        errno = EOPNOTSUPP; \
+        return -1; \
+    }; \
+    return map_info.FIELD; \
+}
+
+// All 6 of these fields are already present in Linux v4.14 (even ACK 4.14-P)
+// while BPF_OBJ_GET_INFO_BY_FD is not implemented at all in v4.9 (even ACK 4.9-Q)
+DEFINE_BPF_GET_FD_INFO(MapType, type)            // int bpfGetFdMapType(const BPF_FD_TYPE map_fd)
+DEFINE_BPF_GET_FD_INFO(MapId, id)                // int bpfGetFdMapId(const BPF_FD_TYPE map_fd)
+DEFINE_BPF_GET_FD_INFO(KeySize, key_size)        // int bpfGetFdKeySize(const BPF_FD_TYPE map_fd)
+DEFINE_BPF_GET_FD_INFO(ValueSize, value_size)    // int bpfGetFdValueSize(const BPF_FD_TYPE map_fd)
+DEFINE_BPF_GET_FD_INFO(MaxEntries, max_entries)  // int bpfGetFdMaxEntries(const BPF_FD_TYPE map_fd)
+DEFINE_BPF_GET_FD_INFO(MapFlags, map_flags)      // int bpfGetFdMapFlags(const BPF_FD_TYPE map_fd)
+
+#undef DEFINE_BPF_GET_FD_INFO
+
 }  // namespace bpf
 }  // namespace android
 
diff --git a/staticlibs/native/bpfmapjni/com_android_net_module_util_BpfMap.cpp b/staticlibs/native/bpfmapjni/com_android_net_module_util_BpfMap.cpp
index e25e17d..2e88fc8 100644
--- a/staticlibs/native/bpfmapjni/com_android_net_module_util_BpfMap.cpp
+++ b/staticlibs/native/bpfmapjni/com_android_net_module_util_BpfMap.cpp
@@ -27,27 +27,18 @@
 
 namespace android {
 
-static jint com_android_net_module_util_BpfMap_closeMap(JNIEnv *env, jobject clazz,
-        jint fd) {
-    int ret = close(fd);
-
-    if (ret) jniThrowErrnoException(env, "closeMap", errno);
-
-    return ret;
-}
-
-static jint com_android_net_module_util_BpfMap_bpfFdGet(JNIEnv *env, jobject clazz,
+static jint com_android_net_module_util_BpfMap_nativeBpfFdGet(JNIEnv *env, jclass clazz,
         jstring path, jint mode) {
     ScopedUtfChars pathname(env, path);
 
     jint fd = bpf::bpfFdGet(pathname.c_str(), static_cast<unsigned>(mode));
 
-    if (fd < 0) jniThrowErrnoException(env, "bpfFdGet", errno);
+    if (fd < 0) jniThrowErrnoException(env, "nativeBpfFdGet", errno);
 
     return fd;
 }
 
-static void com_android_net_module_util_BpfMap_writeToMapEntry(JNIEnv *env, jobject clazz,
+static void com_android_net_module_util_BpfMap_nativeWriteToMapEntry(JNIEnv *env, jobject self,
         jint fd, jbyteArray key, jbyteArray value, jint flags) {
     ScopedByteArrayRO keyRO(env, key);
     ScopedByteArrayRO valueRO(env, value);
@@ -55,7 +46,7 @@
     int ret = bpf::writeToMapEntry(static_cast<int>(fd), keyRO.get(), valueRO.get(),
             static_cast<int>(flags));
 
-    if (ret) jniThrowErrnoException(env, "writeToMapEntry", errno);
+    if (ret) jniThrowErrnoException(env, "nativeWriteToMapEntry", errno);
 }
 
 static jboolean throwIfNotEnoent(JNIEnv *env, const char* functionName, int ret, int err) {
@@ -65,7 +56,7 @@
     return false;
 }
 
-static jboolean com_android_net_module_util_BpfMap_deleteMapEntry(JNIEnv *env, jobject clazz,
+static jboolean com_android_net_module_util_BpfMap_nativeDeleteMapEntry(JNIEnv *env, jobject self,
         jint fd, jbyteArray key) {
     ScopedByteArrayRO keyRO(env, key);
 
@@ -73,10 +64,10 @@
     // to ENOENT.
     int ret = bpf::deleteMapEntry(static_cast<int>(fd), keyRO.get());
 
-    return throwIfNotEnoent(env, "deleteMapEntry", ret, errno);
+    return throwIfNotEnoent(env, "nativeDeleteMapEntry", ret, errno);
 }
 
-static jboolean com_android_net_module_util_BpfMap_getNextMapKey(JNIEnv *env, jobject clazz,
+static jboolean com_android_net_module_util_BpfMap_nativeGetNextMapKey(JNIEnv *env, jobject self,
         jint fd, jbyteArray key, jbyteArray nextKey) {
     // If key is found, the operation returns zero and sets the next key pointer to the key of the
     // next element.  If key is not found, the operation returns zero and sets the next key pointer
@@ -92,10 +83,10 @@
         ret = bpf::getNextMapKey(static_cast<int>(fd), keyRO.get(), nextKeyRW.get());
     }
 
-    return throwIfNotEnoent(env, "getNextMapKey", ret, errno);
+    return throwIfNotEnoent(env, "nativeGetNextMapKey", ret, errno);
 }
 
-static jboolean com_android_net_module_util_BpfMap_findMapEntry(JNIEnv *env, jobject clazz,
+static jboolean com_android_net_module_util_BpfMap_nativeFindMapEntry(JNIEnv *env, jobject self,
         jint fd, jbyteArray key, jbyteArray value) {
     ScopedByteArrayRO keyRO(env, key);
     ScopedByteArrayRW valueRW(env, value);
@@ -104,7 +95,7 @@
     // "value".  If no element is found, the operation returns -1 and sets errno to ENOENT.
     int ret = bpf::findMapEntry(static_cast<int>(fd), keyRO.get(), valueRW.get());
 
-    return throwIfNotEnoent(env, "findMapEntry", ret, errno);
+    return throwIfNotEnoent(env, "nativeFindMapEntry", ret, errno);
 }
 
 /*
@@ -112,18 +103,16 @@
  */
 static const JNINativeMethod gMethods[] = {
     /* name, signature, funcPtr */
-    { "closeMap", "(I)I",
-        (void*) com_android_net_module_util_BpfMap_closeMap },
-    { "bpfFdGet", "(Ljava/lang/String;I)I",
-        (void*) com_android_net_module_util_BpfMap_bpfFdGet },
-    { "writeToMapEntry", "(I[B[BI)V",
-        (void*) com_android_net_module_util_BpfMap_writeToMapEntry },
-    { "deleteMapEntry", "(I[B)Z",
-        (void*) com_android_net_module_util_BpfMap_deleteMapEntry },
-    { "getNextMapKey", "(I[B[B)Z",
-        (void*) com_android_net_module_util_BpfMap_getNextMapKey },
-    { "findMapEntry", "(I[B[B)Z",
-        (void*) com_android_net_module_util_BpfMap_findMapEntry },
+    { "nativeBpfFdGet", "(Ljava/lang/String;I)I",
+        (void*) com_android_net_module_util_BpfMap_nativeBpfFdGet },
+    { "nativeWriteToMapEntry", "(I[B[BI)V",
+        (void*) com_android_net_module_util_BpfMap_nativeWriteToMapEntry },
+    { "nativeDeleteMapEntry", "(I[B)Z",
+        (void*) com_android_net_module_util_BpfMap_nativeDeleteMapEntry },
+    { "nativeGetNextMapKey", "(I[B[B)Z",
+        (void*) com_android_net_module_util_BpfMap_nativeGetNextMapKey },
+    { "nativeFindMapEntry", "(I[B[B)Z",
+        (void*) com_android_net_module_util_BpfMap_nativeFindMapEntry },
 
 };
 
diff --git a/staticlibs/native/bpfmapjni/com_android_net_module_util_TcUtils.cpp b/staticlibs/native/bpfmapjni/com_android_net_module_util_TcUtils.cpp
index 073a46f..cb06afb 100644
--- a/staticlibs/native/bpfmapjni/com_android_net_module_util_TcUtils.cpp
+++ b/staticlibs/native/bpfmapjni/com_android_net_module_util_TcUtils.cpp
@@ -34,7 +34,7 @@
   int error = isEthernet(interface.c_str(), result);
   if (error) {
     throwIOException(
-        env, "com_android_net_module_util_TcUtils_isEthernet error: ", error);
+        env, "com_android_net_module_util_TcUtils_isEthernet error: ", -error);
   }
   // result is not touched when error is returned; leave false.
   return result;
@@ -50,7 +50,7 @@
   if (error) {
     throwIOException(
         env,
-        "com_android_net_module_util_TcUtils_tcFilterAddDevBpf error: ", error);
+        "com_android_net_module_util_TcUtils_tcFilterAddDevBpf error: ", -error);
   }
 }
 
@@ -68,7 +68,7 @@
     throwIOException(env,
                      "com_android_net_module_util_TcUtils_"
                      "tcFilterAddDevIngressPolice error: ",
-                     error);
+                     -error);
   }
 }
 
@@ -80,7 +80,7 @@
   if (error) {
     throwIOException(
         env,
-        "com_android_net_module_util_TcUtils_tcFilterDelDev error: ", error);
+        "com_android_net_module_util_TcUtils_tcFilterDelDev error: ", -error);
   }
 }
 
@@ -92,7 +92,7 @@
   if (error) {
     throwIOException(
         env,
-        "com_android_net_module_util_TcUtils_tcQdiscAddDevClsact error: ", error);
+        "com_android_net_module_util_TcUtils_tcQdiscAddDevClsact error: ", -error);
   }
 }
 
diff --git a/staticlibs/native/tcutils/kernelversion.h b/staticlibs/native/tcutils/kernelversion.h
index 3be1ad2..9aab31d 100644
--- a/staticlibs/native/tcutils/kernelversion.h
+++ b/staticlibs/native/tcutils/kernelversion.h
@@ -32,25 +32,22 @@
 
 namespace android {
 
-static inline unsigned kernelVersion() {
+static inline unsigned uncachedKernelVersion() {
   struct utsname buf;
-  int ret = uname(&buf);
-  if (ret)
-    return 0;
+  if (uname(&buf)) return 0;
 
-  unsigned kver_major;
-  unsigned kver_minor;
-  unsigned kver_sub;
-  char discard;
-  ret = sscanf(buf.release, "%u.%u.%u%c", &kver_major, &kver_minor, &kver_sub,
-               &discard);
-  // Check the device kernel version
-  if (ret < 3)
-    return 0;
-
+  unsigned kver_major = 0;
+  unsigned kver_minor = 0;
+  unsigned kver_sub = 0;
+  (void)sscanf(buf.release, "%u.%u.%u", &kver_major, &kver_minor, &kver_sub);
   return KVER(kver_major, kver_minor, kver_sub);
 }
 
+static unsigned kernelVersion() {
+  static unsigned kver = uncachedKernelVersion();
+  return kver;
+}
+
 static inline bool isAtLeastKernelVersion(unsigned major, unsigned minor,
                                           unsigned sub) {
   return kernelVersion() >= KVER(major, minor, sub);
diff --git a/staticlibs/netd/Android.bp b/staticlibs/netd/Android.bp
index 798fa3a..cfa9bbb 100644
--- a/staticlibs/netd/Android.bp
+++ b/staticlibs/netd/Android.bp
@@ -53,6 +53,14 @@
     min_sdk_version: "29",
 }
 
+// TODO: delete this one when AOSP is no longer auto-merge to git_sc-mainline-prod.
+cc_library_static {
+    name: "netd_aidl_interface-lateststable-cpp",
+    whole_static_libs: [
+        "netd_aidl_interface-V9-cpp",
+    ],
+}
+
 cc_defaults {
     name: "netd_aidl_interface_lateststable_cpp_static",
     static_libs: ["netd_aidl_interface-V9-cpp"],
diff --git a/staticlibs/netd/libnetdutils/InternetAddressesTest.cpp b/staticlibs/netd/libnetdutils/InternetAddressesTest.cpp
index f75fa76..9e37d11 100644
--- a/staticlibs/netd/libnetdutils/InternetAddressesTest.cpp
+++ b/staticlibs/netd/libnetdutils/InternetAddressesTest.cpp
@@ -21,6 +21,7 @@
 #include <vector>
 
 #include <android-base/macros.h>
+#include <fmt/format.h>
 #include <gtest/gtest.h>
 
 #include "netdutils/InternetAddresses.h"
@@ -438,6 +439,192 @@
     }
 }
 
+TEST(IPPrefixTest, containsPrefix) {
+    const struct {
+        const char* prefix;
+        const char* otherPrefix;
+        const bool expected;
+        std::string asParameters() const {
+            return fmt::format("prefix={}, other={}, expect={}", prefix, otherPrefix, expected);
+        }
+    } testExpectations[] = {
+            {"192.0.0.0/8", "192.0.0.0/8", true},
+            {"192.1.0.0/16", "192.1.0.0/16", true},
+            {"192.1.2.0/24", "192.1.2.0/24", true},
+            {"192.1.2.3/32", "192.1.2.3/32", true},
+            {"0.0.0.0/0", "192.0.0.0/8", true},
+            {"0.0.0.0/0", "192.1.0.0/16", true},
+            {"0.0.0.0/0", "192.1.2.0/24", true},
+            {"0.0.0.0/0", "192.1.2.3/32", true},
+            {"192.0.0.0/8", "192.1.0.0/16", true},
+            {"192.0.0.0/8", "192.1.2.0/24", true},
+            {"192.0.0.0/8", "192.1.2.5/32", true},
+            {"192.1.0.0/16", "192.1.2.0/24", true},
+            {"192.1.0.0/16", "192.1.3.6/32", true},
+            {"192.5.6.0/24", "192.5.6.7/32", true},
+            {"192.1.2.3/32", "192.1.2.0/24", false},
+            {"192.1.2.3/32", "192.1.0.0/16", false},
+            {"192.1.2.3/32", "192.0.0.0/8", false},
+            {"192.1.2.3/32", "0.0.0.0/0", false},
+            {"192.1.2.0/24", "192.1.0.0/16", false},
+            {"192.1.2.0/24", "192.0.0.0/8", false},
+            {"192.1.2.0/24", "0.0.0.0/0", false},
+            {"192.9.0.0/16", "192.0.0.0/8", false},
+            {"192.9.0.0/16", "0.0.0.0/0", false},
+            {"192.0.0.0/8", "0.0.0.0/0", false},
+            {"192.0.0.0/8", "191.0.0.0/8", false},
+            {"191.0.0.0/8", "192.0.0.0/8", false},
+            {"192.8.0.0/16", "192.7.0.0/16", false},
+            {"192.7.0.0/16", "192.8.0.0/16", false},
+            {"192.8.6.0/24", "192.7.5.0/24", false},
+            {"192.7.5.0/24", "192.8.6.0/24", false},
+            {"192.8.6.100/32", "192.8.6.200/32", false},
+            {"192.8.6.200/32", "192.8.6.100/32", false},
+            {"192.0.0.0/8", "192.0.0.0/12", true},
+            {"192.0.0.0/12", "192.0.0.0/8", false},
+            {"2001::/16", "2001::/16", true},
+            {"2001:db8::/32", "2001:db8::/32", true},
+            {"2001:db8:cafe::/48", "2001:db8:cafe::/48", true},
+            {"2001:db8:cafe:d00d::/64", "2001:db8:cafe:d00d::/64", true},
+            {"2001:db8:cafe:d00d:fec0::/80", "2001:db8:cafe:d00d:fec0::/80", true},
+            {"2001:db8:cafe:d00d:fec0:de::/96", "2001:db8:cafe:d00d:fec0:de::/96", true},
+            {"2001:db8:cafe:d00d:fec0:de:ac::/112", "2001:db8:cafe:d00d:fec0:de:ac::/112", true},
+            {"2001:db8::cafe:0:1/128", "2001:db8::cafe:0:1/128", true},
+            {"2001::/16", "2001:db8::/32", true},
+            {"2001::/16", "2001:db8:cafe::/48", true},
+            {"2001::/16", "2001:db8:cafe:d00d::/64", true},
+            {"2001::/16", "2001:db8:cafe:d00d:fec0::/80", true},
+            {"2001::/16", "2001:db8:cafe:d00d:fec0:de::/96", true},
+            {"2001::/16", "2001:db8:cafe:d00d:fec0:de:ac::/112", true},
+            {"2001::/16", "2001:db8:cafe:d00d:fec0:de:ac:dd/128", true},
+            {"::/0", "2001::/16", true},
+            {"::/0", "2001:db8::/32", true},
+            {"::/0", "2001:db8:cafe::/48", true},
+            {"::/0", "2001:db8:cafe:d00d::/64", true},
+            {"::/0", "2001:db8:cafe:d00d:fec0::/80", true},
+            {"::/0", "2001:db8:cafe:d00d:fec0:de::/96", true},
+            {"::/0", "2001:db8:cafe:d00d:fec0:de:ac::/112", true},
+            {"::/0", "2001:db8:cafe:d00d:fec0:de:ac:dd/128", true},
+            {"2001:db8::dd/128", "2001::/16", false},
+            {"2001:db8::dd/128", "2001:db8::/32", false},
+            {"2001:db8::dd/128", "2001:db8:cafe::/48", false},
+            {"2001:db8::dd/128", "2001:db8:cafe:d00d::/64", false},
+            {"2001:db8::dd/128", "2001:db8:cafe:d00d:fec0::/80", false},
+            {"2001:db8::dd/128", "2001:db8:cafe:d00d:fec0:de::/96", false},
+            {"2001:db8::dd/128", "2001:db8:cafe:d00d:fec0:de:ac::/112", false},
+            {"2001:db7::/32", "2001:db8::/32", false},
+            {"2001:db8::/32", "2001:db7::/32", false},
+            {"2001:db8:caff::/48", "2001:db8:cafe::/48", false},
+            {"2001:db8:cafe::/48", "2001:db8:caff::/48", false},
+            {"2001:db8:cafe:a00d::/64", "2001:db8:cafe:d00d::/64", false},
+            {"2001:db8:cafe:d00d::/64", "2001:db8:cafe:a00d::/64", false},
+            {"2001:db8:cafe:d00d:fec1::/80", "2001:db8:cafe:d00d:fec0::/80", false},
+            {"2001:db8:cafe:d00d:fec0::/80", "2001:db8:cafe:d00d:fec1::/80", false},
+            {"2001:db8:cafe:d00d:fec0:dd::/96", "2001:db8:cafe:d00d:fec0:ae::/96", false},
+            {"2001:db8:cafe:d00d:fec0:ae::/96", "2001:db8:cafe:d00d:fec0:dd::/96", false},
+            {"2001:db8:cafe:d00d:fec0:de:aa::/112", "2001:db8:cafe:d00d:fec0:de:ac::/112", false},
+            {"2001:db8:cafe:d00d:fec0:de:ac::/112", "2001:db8:cafe:d00d:fec0:de:aa::/112", false},
+            {"2001:db8::cafe:0:123/128", "2001:db8::cafe:0:456/128", false},
+            {"2001:db8::cafe:0:456/128", "2001:db8::cafe:0:123/128", false},
+            {"2001:db8::/32", "2001:db8::/64", true},
+            {"2001:db8::/64", "2001:db8::/32", false},
+            {"::/0", "0.0.0.0/0", false},
+            {"::/0", "1.0.0.0/8", false},
+            {"::/0", "1.2.0.0/16", false},
+            {"::/0", "1.2.3.0/24", false},
+            {"::/0", "1.2.3.4/32", false},
+            {"2001::/16", "1.2.3.4/32", false},
+            {"2001::db8::/32", "1.2.3.4/32", false},
+            {"2001:db8:cafe::/48", "1.2.3.4/32", false},
+            {"2001:db8:cafe:d00d::/64", "1.2.3.4/32", false},
+            {"2001:db8:cafe:d00d:fec0::/80", "1.2.3.4/32", false},
+            {"2001:db8:cafe:d00d:fec0:ae::/96", "1.2.3.4/32", false},
+            {"2001:db8:cafe:d00d:fec0:de:aa::/112", "1.2.3.4/32", false},
+            {"0.0.0.0/0", "::/0", false},
+            {"0.0.0.0/0", "2001::/16", false},
+            {"0.0.0.0/0", "2001::db8::/32", false},
+            {"0.0.0.0/0", "2001:db8:cafe::/48", false},
+            {"0.0.0.0/0", "2001:db8:cafe:d00d::/64", false},
+            {"0.0.0.0/0", "2001:db8:cafe:d00d:fec0::/80", false},
+            {"0.0.0.0/0", "2001:db8:cafe:d00d:fec0:ae::/96", false},
+            {"0.0.0.0/0", "2001:db8:cafe:d00d:fec0:de:aa::/112", false},
+            {"1.2.3.4/32", "2001:db8:cafe:d00d:fec0:de:aa::/112", false},
+            {"1.2.3.0/24", "2001:db8:cafe:d00d:fec0:de:aa::/112", false},
+            {"1.2.0.0/16", "2001:db8:cafe:d00d:fec0:de:aa::/112", false},
+            {"1.0.0.0/8", "2001:db8:cafe:d00d:fec0:de:aa::/112", false},
+    };
+
+    for (const auto& expectation : testExpectations) {
+        SCOPED_TRACE(expectation.asParameters());
+        IPPrefix a = IPPrefix::forString(expectation.prefix);
+        IPPrefix b = IPPrefix::forString(expectation.otherPrefix);
+        EXPECT_EQ(expectation.expected, a.contains(b));
+    }
+}
+
+TEST(IPPrefixTest, containsAddress) {
+    const struct {
+        const char* prefix;
+        const char* address;
+        const bool expected;
+        std::string asParameters() const {
+            return fmt::format("prefix={}, address={}, expect={}", prefix, address, expected);
+        }
+    } testExpectations[] = {
+        {"0.0.0.0/0", "255.255.255.255", true},
+        {"0.0.0.0/0", "1.2.3.4", true},
+        {"0.0.0.0/0", "1.2.3.0", true},
+        {"0.0.0.0/0", "1.2.0.0", true},
+        {"0.0.0.0/0", "1.0.0.0", true},
+        {"0.0.0.0/0", "0.0.0.0", true},
+        {"0.0.0.0/0", "2001:4868:4860::8888", false},
+        {"0.0.0.0/0", "::/0", false},
+        {"192.0.2.0/23", "192.0.2.0", true},
+        {"192.0.2.0/23", "192.0.2.43", true},
+        {"192.0.2.0/23", "192.0.3.21", true},
+        {"192.0.2.0/23", "192.0.0.21", false},
+        {"192.0.2.0/23", "8.8.8.8", false},
+        {"192.0.2.0/23", "2001:4868:4860::8888", false},
+        {"192.0.2.0/23", "::/0", false},
+        {"1.2.3.4/32", "1.2.3.4", true},
+        {"1.2.3.4/32", "1.2.3.5", false},
+        {"10.0.0.0/8", "10.2.0.0", true},
+        {"10.0.0.0/8", "10.2.3.5", true},
+        {"10.0.0.0/8", "10.0.0.0", true},
+        {"10.0.0.0/8", "10.255.255.254", true},
+        {"10.0.0.0/8", "11.0.0.0", false},
+        {"::/0", "2001:db8:f000::ace:d00c", true},
+        {"::/0", "2002:db8:f00::ace:d00d", true},
+        {"::/0", "2001:db7:f00::ace:d00e", true},
+        {"::/0", "2001:db8:f01::bad:d00d", true},
+        {"::/0", "::", true},
+        {"::/0", "0.0.0.0", false},
+        {"::/0", "1.2.3.4", false},
+        {"2001:db8:f00::ace:d00d/127", "2001:db8:f00::ace:d00c", true},
+        {"2001:db8:f00::ace:d00d/127", "2001:db8:f00::ace:d00d", true},
+        {"2001:db8:f00::ace:d00d/127", "2001:db8:f00::ace:d00e", false},
+        {"2001:db8:f00::ace:d00d/127", "2001:db8:f00::bad:d00d", false},
+        {"2001:db8:f00::ace:d00d/127", "2001:4868:4860::8888", false},
+        {"2001:db8:f00::ace:d00d/127", "8.8.8.8", false},
+        {"2001:db8:f00::ace:d00d/127", "0.0.0.0", false},
+        {"2001:db8:f00::ace:d00d/128", "2001:db8:f00::ace:d00d", true},
+        {"2001:db8:f00::ace:d00d/128", "2001:db8:f00::ace:d00c", false},
+        {"2001::/16", "2001::", true},
+        {"2001::/16", "2001:db8:f00::ace:d00d", true},
+        {"2001::/16", "2001:db8:f00::bad:d00d", true},
+        {"2001::/16", "2001::abc", true},
+        {"2001::/16", "2001:ffff:ffff:ffff:ffff:ffff:ffff:ffff", true},
+        {"2001::/16", "2000::", false},
+    };
+
+    for (const auto& expectation : testExpectations) {
+        SCOPED_TRACE(expectation.asParameters());
+        IPPrefix a = IPPrefix::forString(expectation.prefix);
+        IPAddress b = IPAddress::forString(expectation.address);
+        EXPECT_EQ(expectation.expected, a.contains(b));
+    }
+}
+
 TEST(IPPrefixTest, GamutOfOperators) {
     const std::vector<OperatorExpectation<IPPrefix>> kExpectations{
             {EQ, IPPrefix(), IPPrefix()},
diff --git a/staticlibs/netd/libnetdutils/include/netdutils/InternetAddresses.h b/staticlibs/netd/libnetdutils/include/netdutils/InternetAddresses.h
index d5cbe2b..d10cec7 100644
--- a/staticlibs/netd/libnetdutils/include/netdutils/InternetAddresses.h
+++ b/staticlibs/netd/libnetdutils/include/netdutils/InternetAddresses.h
@@ -221,6 +221,12 @@
     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 contains(const IPPrefix& other) {
+        return length() <= other.length() && IPPrefix(other.ip(), length()).ip() == ip();
+    }
+    bool contains(const IPAddress& other) {
+        return IPPrefix(other, length()).ip() == ip();
+    }
 
     bool isUninitialized() const noexcept;
     std::string toString() const noexcept;
diff --git a/staticlibs/tests/unit/src/com/android/net/module/util/Ipv6UtilsTest.java b/staticlibs/tests/unit/src/com/android/net/module/util/Ipv6UtilsTest.java
index 03a1ec9..4866a48 100644
--- a/staticlibs/tests/unit/src/com/android/net/module/util/Ipv6UtilsTest.java
+++ b/staticlibs/tests/unit/src/com/android/net/module/util/Ipv6UtilsTest.java
@@ -131,6 +131,21 @@
         assertEquals(0, icmpv6.code);
     }
 
+    @Test
+    public void testBuildEchoReplyPacket() {
+        final ByteBuffer b = Ipv6Utils.buildEchoReplyPacket(LINK_LOCAL, ALL_NODES);
+
+        Ipv6Header ipv6 = Struct.parse(Ipv6Header.class, b);
+        assertEquals(255, ipv6.hopLimit);
+        assertEquals(OsConstants.IPPROTO_ICMPV6, ipv6.nextHeader);
+        assertEquals(LINK_LOCAL, ipv6.srcIp);
+        assertEquals(ALL_NODES, ipv6.dstIp);
+
+        Icmpv6Header icmpv6 = Struct.parse(Icmpv6Header.class, b);
+        assertEquals(NetworkStackConstants.ICMPV6_ECHO_REPLY_TYPE, icmpv6.type);
+        assertEquals(0, icmpv6.code);
+    }
+
     private void assertPioEquals(PrefixInformationOption pio, String prefix, byte flags,
             long valid, long preferred) {
         assertEquals(NetworkStackConstants.ICMPV6_ND_OPTION_PIO, pio.type);
diff --git a/staticlibs/tests/unit/src/com/android/net/module/util/PacketBuilderTest.java b/staticlibs/tests/unit/src/com/android/net/module/util/PacketBuilderTest.java
index 8f9a1f9..e40cd6b 100644
--- a/staticlibs/tests/unit/src/com/android/net/module/util/PacketBuilderTest.java
+++ b/staticlibs/tests/unit/src/com/android/net/module/util/PacketBuilderTest.java
@@ -17,10 +17,12 @@
 package com.android.net.module.util;
 
 import static android.system.OsConstants.IPPROTO_IP;
+import static android.system.OsConstants.IPPROTO_IPV6;
 import static android.system.OsConstants.IPPROTO_TCP;
 import static android.system.OsConstants.IPPROTO_UDP;
 
 import static com.android.net.module.util.NetworkStackConstants.ETHER_TYPE_IPV4;
+import static com.android.net.module.util.NetworkStackConstants.ETHER_TYPE_IPV6;
 import static com.android.net.module.util.NetworkStackConstants.IPV4_HEADER_MIN_LEN;
 import static com.android.net.module.util.NetworkStackConstants.TCPHDR_ACK;
 import static com.android.net.module.util.NetworkStackConstants.TCP_HEADER_MIN_LEN;
@@ -41,6 +43,7 @@
 
 import com.android.net.module.util.structs.EthernetHeader;
 import com.android.net.module.util.structs.Ipv4Header;
+import com.android.net.module.util.structs.Ipv6Header;
 import com.android.net.module.util.structs.TcpHeader;
 import com.android.net.module.util.structs.UdpHeader;
 
@@ -49,6 +52,7 @@
 
 import java.io.IOException;
 import java.net.Inet4Address;
+import java.net.Inet6Address;
 import java.nio.ByteBuffer;
 
 @RunWith(AndroidJUnit4.class)
@@ -56,8 +60,10 @@
 public class PacketBuilderTest {
     private static final MacAddress SRC_MAC = MacAddress.fromString("11:22:33:44:55:66");
     private static final MacAddress DST_MAC = MacAddress.fromString("aa:bb:cc:dd:ee:ff");
-    private static final Inet4Address IPV4_SRC_ADDR = addr("192.0.2.1");
-    private static final Inet4Address IPV4_DST_ADDR = addr("198.51.100.1");
+    private static final Inet4Address IPV4_SRC_ADDR = addr4("192.0.2.1");
+    private static final Inet4Address IPV4_DST_ADDR = addr4("198.51.100.1");
+    private static final Inet6Address IPV6_SRC_ADDR = addr6("2001:db8::1");
+    private static final Inet6Address IPV6_DST_ADDR = addr6("2001:db8::2");
     private static final short SRC_PORT = 9876;
     private static final short DST_PORT = 433;
     private static final short SEQ_NO = 13579;
@@ -68,6 +74,9 @@
     private static final byte TIME_TO_LIVE = (byte) 0x40;
     private static final short WINDOW = (short) 0x2000;
     private static final short URGENT_POINTER = 0;
+    // version=6, traffic class=0x80, flowlabel=0x515ca;
+    private static final int VERSION_TRAFFICCLASS_FLOWLABEL = 0x680515ca;
+    private static final short HOP_LIMIT = 0x40;
     private static final ByteBuffer DATA = ByteBuffer.wrap(new byte[] {
             (byte) 0xde, (byte) 0xad, (byte) 0xbe, (byte) 0xef
     });
@@ -256,15 +265,239 @@
                 (byte) 0xde, (byte) 0xad, (byte) 0xbe, (byte) 0xef
             };
 
+    private static final byte[] TEST_PACKET_ETHERHDR_IPV6HDR_UDPHDR =
+            new byte[] {
+                // packet = (scapy.Ether(src="11:22:33:44:55:66", dst="aa:bb:cc:dd:ee:ff",
+                //                     type='IPv6') /
+                //           scapy.IPv6(src="2001:db8::1", dst="2001:db8::2", tc=0x80,
+                //                      fl=0x515ca, hlim=0x40) /
+                //           scapy.UDP(sport=9876, dport=433))
+                // Ether header
+                (byte) 0xaa, (byte) 0xbb, (byte) 0xcc, (byte) 0xdd,
+                (byte) 0xee, (byte) 0xff, (byte) 0x11, (byte) 0x22,
+                (byte) 0x33, (byte) 0x44, (byte) 0x55, (byte) 0x66,
+                (byte) 0x86, (byte) 0xdd,
+                // IP header
+                (byte) 0x68, (byte) 0x05, (byte) 0x15, (byte) 0xca,
+                (byte) 0x00, (byte) 0x08, (byte) 0x11, (byte) 0x40,
+                (byte) 0x20, (byte) 0x01, (byte) 0x0d, (byte) 0xb8,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x01,
+                (byte) 0x20, (byte) 0x01, (byte) 0x0d, (byte) 0xb8,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x02,
+                // UDP header
+                (byte) 0x26, (byte) 0x94, (byte) 0x01, (byte) 0xb1,
+                (byte) 0x00, (byte) 0x08, (byte) 0x7c, (byte) 0x24
+            };
+
+    private static final byte[] TEST_PACKET_ETHERHDR_IPV6HDR_UDPHDR_DATA =
+            new byte[] {
+                // packet = (scapy.Ether(src="11:22:33:44:55:66", dst="aa:bb:cc:dd:ee:ff",
+                //                       type='IPv6') /
+                //           scapy.IPv6(src="2001:db8::1", dst="2001:db8::2", tc=0x80,
+                //                      fl=0x515ca, hlim=0x40) /
+                //           scapy.UDP(sport=9876, dport=433) /
+                //           b'\xde\xad\xbe\xef')
+                // Ether header
+                (byte) 0xaa, (byte) 0xbb, (byte) 0xcc, (byte) 0xdd,
+                (byte) 0xee, (byte) 0xff, (byte) 0x11, (byte) 0x22,
+                (byte) 0x33, (byte) 0x44, (byte) 0x55, (byte) 0x66,
+                (byte) 0x86, (byte) 0xdd,
+                // IP header
+                (byte) 0x68, (byte) 0x05, (byte) 0x15, (byte) 0xca,
+                (byte) 0x00, (byte) 0x0c, (byte) 0x11, (byte) 0x40,
+                (byte) 0x20, (byte) 0x01, (byte) 0x0d, (byte) 0xb8,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x01,
+                (byte) 0x20, (byte) 0x01, (byte) 0x0d, (byte) 0xb8,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x02,
+                // UDP header
+                (byte) 0x26, (byte) 0x94, (byte) 0x01, (byte) 0xb1,
+                (byte) 0x00, (byte) 0x0c, (byte) 0xde, (byte) 0x7e,
+                // Data
+                (byte) 0xde, (byte) 0xad, (byte) 0xbe, (byte) 0xef
+            };
+
+    private static final byte[] TEST_PACKET_ETHERHDR_IPV6HDR_TCPHDR_DATA =
+            new byte[] {
+                // packet = (scapy.Ether(src="11:22:33:44:55:66", dst="aa:bb:cc:dd:ee:ff",
+                //                       type='IPv6') /
+                //           scapy.IPv6(src="2001:db8::1", dst="2001:db8::2", tc=0x80,
+                //                      fl=0x515ca, hlim=0x40) /
+                //           scapy.TCP(sport=9876, dport=433, seq=13579, ack=24680,
+                //                     flags='A', window=8192, urgptr=0) /
+                //           b'\xde\xad\xbe\xef')
+                // Ether header
+                (byte) 0xaa, (byte) 0xbb, (byte) 0xcc, (byte) 0xdd,
+                (byte) 0xee, (byte) 0xff, (byte) 0x11, (byte) 0x22,
+                (byte) 0x33, (byte) 0x44, (byte) 0x55, (byte) 0x66,
+                (byte) 0x86, (byte) 0xdd,
+                // IPv6 header
+                (byte) 0x68, (byte) 0x05, (byte) 0x15, (byte) 0xca,
+                (byte) 0x00, (byte) 0x18, (byte) 0x06, (byte) 0x40,
+                (byte) 0x20, (byte) 0x01, (byte) 0x0d, (byte) 0xb8,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x01,
+                (byte) 0x20, (byte) 0x01, (byte) 0x0d, (byte) 0xb8,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x02,
+                // TCP header
+                (byte) 0x26, (byte) 0x94, (byte) 0x01, (byte) 0xb1,
+                (byte) 0x00, (byte) 0x00, (byte) 0x35, (byte) 0x0b,
+                (byte) 0x00, (byte) 0x00, (byte) 0x60, (byte) 0x68,
+                (byte) 0x50, (byte) 0x10, (byte) 0x20, (byte) 0x00,
+                (byte) 0xd9, (byte) 0x05, (byte) 0x00, (byte) 0x00,
+                // Data
+                (byte) 0xde, (byte) 0xad, (byte) 0xbe, (byte) 0xef
+            };
+
+    private static final byte[] TEST_PACKET_ETHERHDR_IPV6HDR_TCPHDR =
+            new byte[] {
+                // packet = (scapy.Ether(src="11:22:33:44:55:66", dst="aa:bb:cc:dd:ee:ff",
+                //                       type='IPv6') /
+                //           scapy.IPv6(src="2001:db8::1", dst="2001:db8::2", tc=0x80,
+                //                      fl=0x515ca, hlim=0x40) /
+                //           scapy.TCP(sport=9876, dport=433, seq=13579, ack=24680,
+                //                     flags='A', window=8192, urgptr=0))
+                // Ether header
+                (byte) 0xaa, (byte) 0xbb, (byte) 0xcc, (byte) 0xdd,
+                (byte) 0xee, (byte) 0xff, (byte) 0x11, (byte) 0x22,
+                (byte) 0x33, (byte) 0x44, (byte) 0x55, (byte) 0x66,
+                (byte) 0x86, (byte) 0xdd,
+                // IPv6 header
+                (byte) 0x68, (byte) 0x05, (byte) 0x15, (byte) 0xca,
+                (byte) 0x00, (byte) 0x14, (byte) 0x06, (byte) 0x40,
+                (byte) 0x20, (byte) 0x01, (byte) 0x0d, (byte) 0xb8,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x01,
+                (byte) 0x20, (byte) 0x01, (byte) 0x0d, (byte) 0xb8,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x02,
+                // TCP header
+                (byte) 0x26, (byte) 0x94, (byte) 0x01, (byte) 0xb1,
+                (byte) 0x00, (byte) 0x00, (byte) 0x35, (byte) 0x0b,
+                (byte) 0x00, (byte) 0x00, (byte) 0x60, (byte) 0x68,
+                (byte) 0x50, (byte) 0x10, (byte) 0x20, (byte) 0x00,
+                (byte) 0x76, (byte) 0xa7, (byte) 0x00, (byte) 0x00
+            };
+
+    private static final byte[] TEST_PACKET_IPV6HDR_TCPHDR_DATA =
+            new byte[] {
+                // packet = (scapy.IPv6(src="2001:db8::1", dst="2001:db8::2", tc=0x80,
+                //                      fl=0x515ca, hlim=0x40) /
+                //           scapy.TCP(sport=9876, dport=433, seq=13579, ack=24680,
+                //                     flags='A', window=8192, urgptr=0) /
+                //           b'\xde\xad\xbe\xef')
+                // IPv6 header
+                (byte) 0x68, (byte) 0x05, (byte) 0x15, (byte) 0xca,
+                (byte) 0x00, (byte) 0x18, (byte) 0x06, (byte) 0x40,
+                (byte) 0x20, (byte) 0x01, (byte) 0x0d, (byte) 0xb8,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x01,
+                (byte) 0x20, (byte) 0x01, (byte) 0x0d, (byte) 0xb8,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x02,
+                // TCP header
+                (byte) 0x26, (byte) 0x94, (byte) 0x01, (byte) 0xb1,
+                (byte) 0x00, (byte) 0x00, (byte) 0x35, (byte) 0x0b,
+                (byte) 0x00, (byte) 0x00, (byte) 0x60, (byte) 0x68,
+                (byte) 0x50, (byte) 0x10, (byte) 0x20, (byte) 0x00,
+                (byte) 0xd9, (byte) 0x05, (byte) 0x00, (byte) 0x00,
+                // Data
+                (byte) 0xde, (byte) 0xad, (byte) 0xbe, (byte) 0xef
+            };
+
+    private static final byte[] TEST_PACKET_IPV6HDR_TCPHDR =
+            new byte[] {
+                // packet = (scapy.IPv6(src="2001:db8::1", dst="2001:db8::2", tc=0x80,
+                //                      fl=0x515ca, hlim=0x40) /
+                //           scapy.TCP(sport=9876, dport=433, seq=13579, ack=24680,
+                //                     flags='A', window=8192, urgptr=0))
+                // IPv6 header
+                (byte) 0x68, (byte) 0x05, (byte) 0x15, (byte) 0xca,
+                (byte) 0x00, (byte) 0x14, (byte) 0x06, (byte) 0x40,
+                (byte) 0x20, (byte) 0x01, (byte) 0x0d, (byte) 0xb8,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x01,
+                (byte) 0x20, (byte) 0x01, (byte) 0x0d, (byte) 0xb8,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x02,
+                // TCP header
+                (byte) 0x26, (byte) 0x94, (byte) 0x01, (byte) 0xb1,
+                (byte) 0x00, (byte) 0x00, (byte) 0x35, (byte) 0x0b,
+                (byte) 0x00, (byte) 0x00, (byte) 0x60, (byte) 0x68,
+                (byte) 0x50, (byte) 0x10, (byte) 0x20, (byte) 0x00,
+                (byte) 0x76, (byte) 0xa7, (byte) 0x00, (byte) 0x00
+            };
+
+    private static final byte[] TEST_PACKET_IPV6HDR_UDPHDR =
+            new byte[] {
+                // packet = (scapy.IPv6(src="2001:db8::1", dst="2001:db8::2", tc=0x80,
+                //                      fl=0x515ca, hlim=0x40) /
+                //           scapy.UDP(sport=9876, dport=433))
+                // IP header
+                (byte) 0x68, (byte) 0x05, (byte) 0x15, (byte) 0xca,
+                (byte) 0x00, (byte) 0x08, (byte) 0x11, (byte) 0x40,
+                (byte) 0x20, (byte) 0x01, (byte) 0x0d, (byte) 0xb8,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x01,
+                (byte) 0x20, (byte) 0x01, (byte) 0x0d, (byte) 0xb8,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x02,
+                // UDP header
+                (byte) 0x26, (byte) 0x94, (byte) 0x01, (byte) 0xb1,
+                (byte) 0x00, (byte) 0x08, (byte) 0x7c, (byte) 0x24
+            };
+
+    private static final byte[] TEST_PACKET_IPV6HDR_UDPHDR_DATA =
+            new byte[] {
+                // packet = (scapy.IPv6(src="2001:db8::1", dst="2001:db8::2", tc=0x80,
+                //                      fl=0x515ca, hlim=0x40) /
+                //           scapy.UDP(sport=9876, dport=433) /
+                //           b'\xde\xad\xbe\xef')
+                // IP header
+                (byte) 0x68, (byte) 0x05, (byte) 0x15, (byte) 0xca,
+                (byte) 0x00, (byte) 0x0c, (byte) 0x11, (byte) 0x40,
+                (byte) 0x20, (byte) 0x01, (byte) 0x0d, (byte) 0xb8,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x01,
+                (byte) 0x20, (byte) 0x01, (byte) 0x0d, (byte) 0xb8,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+                (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x02,
+                // UDP header
+                (byte) 0x26, (byte) 0x94, (byte) 0x01, (byte) 0xb1,
+                (byte) 0x00, (byte) 0x0c, (byte) 0xde, (byte) 0x7e,
+                // Data
+                (byte) 0xde, (byte) 0xad, (byte) 0xbe, (byte) 0xef
+            };
+
     /**
-     * Build an IPv4 packet which has ether header, IPv4 header, TCP/UDP header and data.
+     * Build a packet which has ether header, IP header, TCP/UDP header and data.
      * The ethernet header and data are optional. Note that both source mac address and
      * destination mac address are required for ethernet header.
      *
      * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      * |                Layer 2 header (EthernetHeader)                | (optional)
      * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-     * |                  Layer 3 header (Ipv4Header)                  |
+     * |           Layer 3 header (Ipv4Header, Ipv6Header)             |
      * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      * |           Layer 4 header (TcpHeader, UdpHeader)               |
      * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
@@ -273,33 +506,55 @@
      *
      * @param srcMac source MAC address. used by L2 ether header.
      * @param dstMac destination MAC address. used by L2 ether header.
-     * @param l4proto the layer 4 protocol. support either IPPROTO_TCP or IPPROTO_UDP.
+     * @param l3proto the layer 3 protocol. Only {@code IPPROTO_IP} and {@code IPPROTO_IPV6}
+     *        currently supported.
+     * @param l4proto the layer 4 protocol. Only {@code IPPROTO_TCP} and {@code IPPROTO_UDP}
+     *        currently supported.
      * @param payload the payload.
      */
     @NonNull
-    private ByteBuffer buildIpv4Packet(@Nullable final MacAddress srcMac,
-            @Nullable final MacAddress dstMac, final int l4proto,
+    private ByteBuffer buildPacket(@Nullable final MacAddress srcMac,
+            @Nullable final MacAddress dstMac, final int l3proto, final int l4proto,
             @Nullable final ByteBuffer payload)
             throws Exception {
+        if (l3proto != IPPROTO_IP && l3proto != IPPROTO_IPV6) {
+            fail("Unsupported layer 3 protocol " + l3proto);
+        }
+
         if (l4proto != IPPROTO_TCP && l4proto != IPPROTO_UDP) {
             fail("Unsupported layer 4 protocol " + l4proto);
         }
 
         final boolean hasEther = (srcMac != null && dstMac != null);
         final int payloadLen = (payload == null) ? 0 : payload.limit();
-        final ByteBuffer buffer = PacketBuilder.allocate(hasEther, IPPROTO_IP, l4proto,
+        final ByteBuffer buffer = PacketBuilder.allocate(hasEther, l3proto, l4proto,
                 payloadLen);
         final PacketBuilder packetBuilder = new PacketBuilder(buffer);
 
-        if (hasEther) packetBuilder.writeL2Header(srcMac, dstMac, (short) ETHER_TYPE_IPV4);
-        packetBuilder.writeIpv4Header(TYPE_OF_SERVICE, ID, FLAGS_AND_FRAGMENT_OFFSET,
-                TIME_TO_LIVE, (byte) l4proto, IPV4_SRC_ADDR, IPV4_DST_ADDR);
+        // [1] Build ether header.
+        if (hasEther) {
+            final int etherType = (l3proto == IPPROTO_IP) ? ETHER_TYPE_IPV4 : ETHER_TYPE_IPV6;
+            packetBuilder.writeL2Header(srcMac, dstMac, (short) etherType);
+        }
+
+        // [2] Build IP header.
+        if (l3proto == IPPROTO_IP) {
+            packetBuilder.writeIpv4Header(TYPE_OF_SERVICE, ID, FLAGS_AND_FRAGMENT_OFFSET,
+                    TIME_TO_LIVE, (byte) l4proto, IPV4_SRC_ADDR, IPV4_DST_ADDR);
+        } else if (l3proto == IPPROTO_IPV6) {
+            packetBuilder.writeIpv6Header(VERSION_TRAFFICCLASS_FLOWLABEL,
+                    (byte) l4proto, HOP_LIMIT, IPV6_SRC_ADDR, IPV6_DST_ADDR);
+        }
+
+        // [3] Build TCP or UDP header.
         if (l4proto == IPPROTO_TCP) {
             packetBuilder.writeTcpHeader(SRC_PORT, DST_PORT, SEQ_NO, ACK_NO,
                     TCPHDR_ACK, WINDOW, URGENT_POINTER);
         } else if (l4proto == IPPROTO_UDP) {
             packetBuilder.writeUdpHeader(SRC_PORT, DST_PORT);
         }
+
+        // [4] Build payload.
         if (payload != null) {
             buffer.put(payload);
             // in case data might be reused by caller, restore the position and
@@ -313,19 +568,27 @@
     /**
      * Check ethernet header.
      *
+     * @param l3proto the layer 3 protocol. Only {@code IPPROTO_IP} and {@code IPPROTO_IPV6}
+     *        currently supported.
      * @param actual the packet to check.
      */
-    private void checkEtherHeader(final ByteBuffer actual) {
+    private void checkEtherHeader(final int l3proto, final ByteBuffer actual) {
+        if (l3proto != IPPROTO_IP && l3proto != IPPROTO_IPV6) {
+            fail("Unsupported layer 3 protocol " + l3proto);
+        }
+
         final EthernetHeader eth = Struct.parse(EthernetHeader.class, actual);
         assertEquals(SRC_MAC, eth.srcMac);
         assertEquals(DST_MAC, eth.dstMac);
-        assertEquals(ETHER_TYPE_IPV4, eth.etherType);
+        final int expectedEtherType = (l3proto == IPPROTO_IP) ? ETHER_TYPE_IPV4 : ETHER_TYPE_IPV6;
+        assertEquals(expectedEtherType, eth.etherType);
     }
 
     /**
      * Check IPv4 header.
      *
-     * @param l4proto the layer 4 protocol. support either IPPROTO_TCP or IPPROTO_UDP.
+     * @param l4proto the layer 4 protocol. Only {@code IPPROTO_TCP} and {@code IPPROTO_UDP}
+     *        currently supported.
      * @param hasData true if the packet has data payload; false otherwise.
      * @param actual the packet to check.
      */
@@ -359,19 +622,64 @@
     }
 
     /**
-     * Check TCPv4 packet.
+     * Check IPv6 header.
      *
-     * @param hasEther true if the packet has ether header; false otherwise.
+     * @param l4proto the layer 4 protocol. Only {@code IPPROTO_TCP} and {@code IPPROTO_UDP}
+     *        currently supported.
      * @param hasData true if the packet has data payload; false otherwise.
      * @param actual the packet to check.
      */
-    private void checkTcpv4Packet(final boolean hasEther, final boolean hasData,
+    private void checkIpv6Header(final int l4proto, final boolean hasData,
             final ByteBuffer actual) {
-        if (hasEther) {
-            checkEtherHeader(actual);
+        if (l4proto != IPPROTO_TCP && l4proto != IPPROTO_UDP) {
+            fail("Unsupported layer 4 protocol " + l4proto);
         }
-        checkIpv4Header(IPPROTO_TCP, hasData, actual);
 
+        final Ipv6Header ipv6Header = Struct.parse(Ipv6Header.class, actual);
+
+        assertEquals(VERSION_TRAFFICCLASS_FLOWLABEL, ipv6Header.vtf);
+        assertEquals(HOP_LIMIT, ipv6Header.hopLimit);
+        assertEquals(IPV6_SRC_ADDR, ipv6Header.srcIp);
+        assertEquals(IPV6_DST_ADDR, ipv6Header.dstIp);
+
+        final int dataLength = hasData ? DATA.limit() : 0;
+        if (l4proto == IPPROTO_TCP) {
+            assertEquals(TCP_HEADER_MIN_LEN + dataLength, ipv6Header.payloadLength);
+            assertEquals((byte) IPPROTO_TCP, ipv6Header.nextHeader);
+        } else if (l4proto == IPPROTO_UDP) {
+            assertEquals(UDP_HEADER_LEN + dataLength, ipv6Header.payloadLength);
+            assertEquals((byte) IPPROTO_UDP, ipv6Header.nextHeader);
+        }
+    }
+
+    /**
+     * Check TCP packet.
+     *
+     * @param hasEther true if the packet has ether header; false otherwise.
+     * @param l3proto the layer 3 protocol. Only {@code IPPROTO_IP} and {@code IPPROTO_IPV6}
+     *        currently supported.
+     * @param hasData true if the packet has data payload; false otherwise.
+     * @param actual the packet to check.
+     */
+    private void checkTcpPacket(final boolean hasEther, final int l3proto, final boolean hasData,
+            final ByteBuffer actual) {
+        if (l3proto != IPPROTO_IP && l3proto != IPPROTO_IPV6) {
+            fail("Unsupported layer 3 protocol " + l3proto);
+        }
+
+        // [1] Check ether header.
+        if (hasEther) {
+            checkEtherHeader(l3proto, actual);
+        }
+
+        // [2] Check IP header.
+        if (l3proto == IPPROTO_IP) {
+            checkIpv4Header(IPPROTO_TCP, hasData, actual);
+        } else if (l3proto == IPPROTO_IPV6) {
+            checkIpv6Header(IPPROTO_TCP, hasData, actual);
+        }
+
+        // [3] Check TCP header.
         final TcpHeader tcpHeader = Struct.parse(TcpHeader.class, actual);
         assertEquals(SRC_PORT, tcpHeader.srcPort);
         assertEquals(DST_PORT, tcpHeader.dstPort);
@@ -380,35 +688,59 @@
         assertEquals((short) 0x5010 /* offset=5(*4bytes), control bits=ACK */,
                 tcpHeader.dataOffsetAndControlBits);
         assertEquals(WINDOW, tcpHeader.window);
-        assertEquals(hasData ? (short) 0x4844 : (short) 0xe5e5, tcpHeader.checksum);
         assertEquals(URGENT_POINTER, tcpHeader.urgentPointer);
+        if (l3proto == IPPROTO_IP) {
+            assertEquals(hasData ? (short) 0x4844 : (short) 0xe5e5, tcpHeader.checksum);
+        } else if (l3proto == IPPROTO_IPV6) {
+            assertEquals(hasData ? (short) 0xd905 : (short) 0x76a7, tcpHeader.checksum);
+        }
 
+        // [4] Check payload.
         if (hasData) {
             assertEquals(0xdeadbeef, actual.getInt());
         }
     }
 
     /**
-     * Check UDPv4 packet.
+     * Check UDP packet.
      *
      * @param hasEther true if the packet has ether header; false otherwise.
+     * @param l3proto the layer 3 protocol. Only {@code IPPROTO_IP} and {@code IPPROTO_IPV6}
+     *        currently supported.
      * @param hasData true if the packet has data payload; false otherwise.
      * @param actual the packet to check.
      */
-    private void checkUdpv4Packet(final boolean hasEther, final boolean hasData,
+    private void checkUdpPacket(final boolean hasEther, final int l3proto, final boolean hasData,
             final ByteBuffer actual) {
-        if (hasEther) {
-            checkEtherHeader(actual);
+        if (l3proto != IPPROTO_IP && l3proto != IPPROTO_IPV6) {
+            fail("Unsupported layer 3 protocol " + l3proto);
         }
-        checkIpv4Header(IPPROTO_UDP, hasData, actual);
 
+        // [1] Check ether header.
+        if (hasEther) {
+            checkEtherHeader(l3proto, actual);
+        }
+
+        // [2] Check IP header.
+        if (l3proto == IPPROTO_IP) {
+            checkIpv4Header(IPPROTO_UDP, hasData, actual);
+        } else if (l3proto == IPPROTO_IPV6) {
+            checkIpv6Header(IPPROTO_UDP, hasData, actual);
+        }
+
+        // [3] Check UDP header.
         final UdpHeader udpHeader = Struct.parse(UdpHeader.class, actual);
         assertEquals(SRC_PORT, udpHeader.srcPort);
         assertEquals(DST_PORT, udpHeader.dstPort);
         final int dataLength = hasData ? DATA.limit() : 0;
         assertEquals(UDP_HEADER_LEN + dataLength, udpHeader.length);
-        assertEquals(hasData ? (short) 0x4dbd : (short) 0xeb62, udpHeader.checksum);
+        if (l3proto == IPPROTO_IP) {
+            assertEquals(hasData ? (short) 0x4dbd : (short) 0xeb62, udpHeader.checksum);
+        } else if (l3proto == IPPROTO_IPV6) {
+            assertEquals(hasData ? (short) 0xde7e : (short) 0x7c24, udpHeader.checksum);
+        }
 
+        // [4] Check payload.
         if (hasData) {
             assertEquals(0xdeadbeef, actual.getInt());
         }
@@ -416,66 +748,133 @@
 
     @Test
     public void testBuildPacketEtherIPv4Tcp() throws Exception {
-        final ByteBuffer packet = buildIpv4Packet(SRC_MAC, DST_MAC, IPPROTO_TCP, null /* data */);
-        checkTcpv4Packet(true /* hasEther */, false /* hasData */, packet);
+        final ByteBuffer packet = buildPacket(SRC_MAC, DST_MAC, IPPROTO_IP, IPPROTO_TCP,
+                null /* data */);
+        checkTcpPacket(true /* hasEther */, IPPROTO_IP, false /* hasData */, packet);
         assertArrayEquals(TEST_PACKET_ETHERHDR_IPV4HDR_TCPHDR, packet.array());
     }
 
     @Test
     public void testBuildPacketEtherIPv4TcpData() throws Exception {
-        final ByteBuffer packet = buildIpv4Packet(SRC_MAC, DST_MAC, IPPROTO_TCP, DATA);
-        checkTcpv4Packet(true /* hasEther */, true /* hasData */, packet);
+        final ByteBuffer packet = buildPacket(SRC_MAC, DST_MAC, IPPROTO_IP, IPPROTO_TCP, DATA);
+        checkTcpPacket(true /* hasEther */, IPPROTO_IP, true /* hasData */, packet);
         assertArrayEquals(TEST_PACKET_ETHERHDR_IPV4HDR_TCPHDR_DATA,
                 packet.array());
     }
 
     @Test
     public void testBuildPacketIPv4Tcp() throws Exception {
-        final ByteBuffer packet = buildIpv4Packet(null /* srcMac */, null /* dstMac */,
-                IPPROTO_TCP, null /* data */);
-        checkTcpv4Packet(false /* hasEther */, false /* hasData */, packet);
+        final ByteBuffer packet = buildPacket(null /* srcMac */, null /* dstMac */,
+                IPPROTO_IP, IPPROTO_TCP, null /* data */);
+        checkTcpPacket(false /* hasEther */, IPPROTO_IP, false /* hasData */, packet);
         assertArrayEquals(TEST_PACKET_IPV4HDR_TCPHDR, packet.array());
     }
 
     @Test
     public void testBuildPacketIPv4TcpData() throws Exception {
-        final ByteBuffer packet = buildIpv4Packet(null /* srcMac */, null /* dstMac */,
-                IPPROTO_TCP, DATA);
-        checkTcpv4Packet(false /* hasEther */, true /* hasData */, packet);
+        final ByteBuffer packet = buildPacket(null /* srcMac */, null /* dstMac */,
+                IPPROTO_IP, IPPROTO_TCP, DATA);
+        checkTcpPacket(false /* hasEther */, IPPROTO_IP, true /* hasData */, packet);
         assertArrayEquals(TEST_PACKET_IPV4HDR_TCPHDR_DATA, packet.array());
     }
 
     @Test
     public void testBuildPacketEtherIPv4Udp() throws Exception {
-        final ByteBuffer packet = buildIpv4Packet(SRC_MAC, DST_MAC, IPPROTO_UDP, null /* data */);
-        checkUdpv4Packet(true /* hasEther */, false /* hasData */, packet);
+        final ByteBuffer packet = buildPacket(SRC_MAC, DST_MAC, IPPROTO_IP, IPPROTO_UDP,
+                null /* data */);
+        checkUdpPacket(true /* hasEther */, IPPROTO_IP, false /* hasData */, packet);
         assertArrayEquals(TEST_PACKET_ETHERHDR_IPV4HDR_UDPHDR, packet.array());
     }
 
     @Test
     public void testBuildPacketEtherIPv4UdpData() throws Exception {
-        final ByteBuffer packet = buildIpv4Packet(SRC_MAC, DST_MAC, IPPROTO_UDP, DATA);
-        checkUdpv4Packet(true /* hasEther */, true /* hasData */, packet);
+        final ByteBuffer packet = buildPacket(SRC_MAC, DST_MAC, IPPROTO_IP, IPPROTO_UDP, DATA);
+        checkUdpPacket(true /* hasEther */, IPPROTO_IP, true /* hasData */, packet);
         assertArrayEquals(TEST_PACKET_ETHERHDR_IPV4HDR_UDPHDR_DATA, packet.array());
     }
 
     @Test
     public void testBuildPacketIPv4Udp() throws Exception {
-        final ByteBuffer packet = buildIpv4Packet(null /* srcMac */, null /* dstMac */,
-                IPPROTO_UDP, null /*data*/);
-        checkUdpv4Packet(false /* hasEther */, false /* hasData */, packet);
+        final ByteBuffer packet = buildPacket(null /* srcMac */, null /* dstMac */,
+                IPPROTO_IP, IPPROTO_UDP, null /*data*/);
+        checkUdpPacket(false /* hasEther */, IPPROTO_IP, false /* hasData */, packet);
         assertArrayEquals(TEST_PACKET_IPV4HDR_UDPHDR, packet.array());
     }
 
     @Test
     public void testBuildPacketIPv4UdpData() throws Exception {
-        final ByteBuffer packet = buildIpv4Packet(null /* srcMac */, null /* dstMac */,
-                IPPROTO_UDP, DATA);
-        checkUdpv4Packet(false /* hasEther */, true /* hasData */, packet);
+        final ByteBuffer packet = buildPacket(null /* srcMac */, null /* dstMac */,
+                IPPROTO_IP, IPPROTO_UDP, DATA);
+        checkUdpPacket(false /* hasEther */, IPPROTO_IP, true /* hasData */, packet);
         assertArrayEquals(TEST_PACKET_IPV4HDR_UDPHDR_DATA, packet.array());
     }
 
     @Test
+    public void testBuildPacketEtherIPv6TcpData() throws Exception {
+        final ByteBuffer packet = buildPacket(SRC_MAC, DST_MAC, IPPROTO_IPV6, IPPROTO_TCP, DATA);
+        checkTcpPacket(true /* hasEther */, IPPROTO_IPV6, true /* hasData */, packet);
+        assertArrayEquals(TEST_PACKET_ETHERHDR_IPV6HDR_TCPHDR_DATA,
+                packet.array());
+    }
+
+    @Test
+    public void testBuildPacketEtherIPv6Tcp() throws Exception {
+        final ByteBuffer packet = buildPacket(SRC_MAC, DST_MAC, IPPROTO_IPV6, IPPROTO_TCP,
+                null /*data*/);
+        checkTcpPacket(true /* hasEther */, IPPROTO_IPV6, false /* hasData */, packet);
+        assertArrayEquals(TEST_PACKET_ETHERHDR_IPV6HDR_TCPHDR,
+                packet.array());
+    }
+
+    @Test
+    public void testBuildPacketIPv6TcpData() throws Exception {
+        final ByteBuffer packet = buildPacket(null /* srcMac */, null /* dstMac */, IPPROTO_IPV6,
+                IPPROTO_TCP, DATA);
+        checkTcpPacket(false /* hasEther */, IPPROTO_IPV6, true /* hasData */, packet);
+        assertArrayEquals(TEST_PACKET_IPV6HDR_TCPHDR_DATA, packet.array());
+    }
+
+    @Test
+    public void testBuildPacketIPv6Tcp() throws Exception {
+        final ByteBuffer packet = buildPacket(null /* srcMac */, null /* dstMac */, IPPROTO_IPV6,
+                IPPROTO_TCP, null /*data*/);
+        checkTcpPacket(false /* hasEther */, IPPROTO_IPV6, false /* hasData */, packet);
+        assertArrayEquals(TEST_PACKET_IPV6HDR_TCPHDR, packet.array());
+    }
+
+    @Test
+    public void testBuildPacketEtherIPv6Udp() throws Exception {
+        final ByteBuffer packet = buildPacket(SRC_MAC, DST_MAC, IPPROTO_IPV6, IPPROTO_UDP,
+                null /* data */);
+        checkUdpPacket(true /* hasEther */, IPPROTO_IPV6, false /* hasData */, packet);
+        assertArrayEquals(TEST_PACKET_ETHERHDR_IPV6HDR_UDPHDR, packet.array());
+    }
+
+    @Test
+    public void testBuildPacketEtherIPv6UdpData() throws Exception {
+        final ByteBuffer packet = buildPacket(SRC_MAC, DST_MAC, IPPROTO_IPV6, IPPROTO_UDP,
+                DATA);
+        checkUdpPacket(true /* hasEther */, IPPROTO_IPV6, true /* hasData */, packet);
+        assertArrayEquals(TEST_PACKET_ETHERHDR_IPV6HDR_UDPHDR_DATA, packet.array());
+    }
+
+    @Test
+    public void testBuildPacketIPv6Udp() throws Exception {
+        final ByteBuffer packet = buildPacket(null /* srcMac */, null /* dstMac */,
+                IPPROTO_IPV6, IPPROTO_UDP, null /*data*/);
+        checkUdpPacket(false /* hasEther */, IPPROTO_IPV6, false /* hasData */, packet);
+        assertArrayEquals(TEST_PACKET_IPV6HDR_UDPHDR, packet.array());
+    }
+
+    @Test
+    public void testBuildPacketIPv6UdpData() throws Exception {
+        final ByteBuffer packet = buildPacket(null /* srcMac */, null /* dstMac */,
+                IPPROTO_IPV6, IPPROTO_UDP, DATA);
+        checkUdpPacket(false /* hasEther */, IPPROTO_IPV6, true /* hasData */, packet);
+        assertArrayEquals(TEST_PACKET_IPV6HDR_UDPHDR_DATA, packet.array());
+    }
+
+    @Test
     public void testFinalizePacketWithoutIpv4Header() throws Exception {
         final ByteBuffer buffer = PacketBuilder.allocate(false /* hasEther */, IPPROTO_IP,
                 IPPROTO_TCP, 0 /* payloadLen */);
@@ -526,7 +925,11 @@
         assertThrows(IOException.class, () -> packetBuilder.writeUdpHeader(SRC_PORT, DST_PORT));
     }
 
-    private static Inet4Address addr(String addr) {
+    private static Inet4Address addr4(String addr) {
         return (Inet4Address) InetAddresses.parseNumericAddress(addr);
     }
+
+    private static Inet6Address addr6(String addr) {
+        return (Inet6Address) InetAddresses.parseNumericAddress(addr);
+    }
 }
diff --git a/staticlibs/tests/unit/src/com/android/net/module/util/PerUidCounterTest.kt b/staticlibs/tests/unit/src/com/android/net/module/util/PerUidCounterTest.kt
new file mode 100644
index 0000000..0f2d52a
--- /dev/null
+++ b/staticlibs/tests/unit/src/com/android/net/module/util/PerUidCounterTest.kt
@@ -0,0 +1,109 @@
+/*
+ * 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.
+ */
+
+package com.android.net.module.util
+
+import androidx.test.filters.SmallTest
+import androidx.test.runner.AndroidJUnit4
+import org.junit.Test
+import org.junit.runner.RunWith
+import kotlin.test.assertFailsWith
+
+@RunWith(AndroidJUnit4::class)
+@SmallTest
+class PerUidCounterTest {
+    private val UID_A = 1000
+    private val UID_B = 1001
+
+    @Test
+    fun testCounterMaximum() {
+        assertFailsWith<IllegalArgumentException> {
+            PerUidCounter(-1)
+        }
+        assertFailsWith<IllegalArgumentException> {
+            PerUidCounter(0)
+        }
+
+        val largeMaxCounter = PerUidCounter(Integer.MAX_VALUE)
+        largeMaxCounter.incrementCountOrThrow(UID_A, Integer.MAX_VALUE)
+        assertFailsWith<IllegalStateException> {
+            largeMaxCounter.incrementCountOrThrow(UID_A)
+        }
+    }
+
+    @Test
+    fun testIncrementCountOrThrow() {
+        val counter = PerUidCounter(3)
+
+        // Verify the increment count cannot be zero.
+        assertFailsWith<IllegalArgumentException> {
+            counter.incrementCountOrThrow(UID_A, 0)
+        }
+
+        // Verify the counters work independently.
+        counter.incrementCountOrThrow(UID_A)
+        counter.incrementCountOrThrow(UID_B, 2)
+        counter.incrementCountOrThrow(UID_B)
+        counter.incrementCountOrThrow(UID_A)
+        counter.incrementCountOrThrow(UID_A)
+        assertFailsWith<IllegalStateException> {
+            counter.incrementCountOrThrow(UID_A)
+        }
+        assertFailsWith<IllegalStateException> {
+            counter.incrementCountOrThrow(UID_B)
+        }
+
+        // Verify exception can be triggered again.
+        assertFailsWith<IllegalStateException> {
+            counter.incrementCountOrThrow(UID_A)
+        }
+        assertFailsWith<IllegalStateException> {
+            counter.incrementCountOrThrow(UID_A, 3)
+        }
+    }
+
+    @Test
+    fun testDecrementCountOrThrow() {
+        val counter = PerUidCounter(3)
+
+        // Verify the decrement count cannot be zero.
+        assertFailsWith<IllegalArgumentException> {
+            counter.decrementCountOrThrow(UID_A, 0)
+        }
+
+        // Verify the count cannot go below zero.
+        assertFailsWith<IllegalStateException> {
+            counter.decrementCountOrThrow(UID_A)
+        }
+        assertFailsWith<IllegalStateException> {
+            counter.decrementCountOrThrow(UID_A, 5)
+        }
+        assertFailsWith<IllegalStateException> {
+            counter.decrementCountOrThrow(UID_A, Integer.MAX_VALUE)
+        }
+
+        // Verify the counters work independently.
+        counter.incrementCountOrThrow(UID_A)
+        counter.incrementCountOrThrow(UID_B)
+        assertFailsWith<IllegalStateException> {
+            counter.decrementCountOrThrow(UID_A, 3)
+        }
+        counter.decrementCountOrThrow(UID_A)
+        assertFailsWith<IllegalStateException> {
+            counter.decrementCountOrThrow(UID_A)
+        }
+    }
+}
\ No newline at end of file
diff --git a/staticlibs/tests/unit/src/com/android/net/module/util/netlink/RtNetlinkRouteMessageTest.java b/staticlibs/tests/unit/src/com/android/net/module/util/netlink/RtNetlinkRouteMessageTest.java
index 392314f..55cfd50 100644
--- a/staticlibs/tests/unit/src/com/android/net/module/util/netlink/RtNetlinkRouteMessageTest.java
+++ b/staticlibs/tests/unit/src/com/android/net/module/util/netlink/RtNetlinkRouteMessageTest.java
@@ -63,15 +63,7 @@
         return ByteBuffer.wrap(HexDump.hexStringToByteArray(hexString));
     }
 
-    @Test
-    public void testParseRtmRouteAddress() {
-        final ByteBuffer byteBuffer = toByteBuffer(RTM_NEWROUTE_HEX);
-        byteBuffer.order(ByteOrder.LITTLE_ENDIAN);  // For testing.
-        final NetlinkMessage msg = NetlinkMessage.parse(byteBuffer, NETLINK_ROUTE);
-        assertNotNull(msg);
-        assertTrue(msg instanceof RtNetlinkRouteMessage);
-        final RtNetlinkRouteMessage routeMsg = (RtNetlinkRouteMessage) msg;
-
+    private void assertRtmRouteMessage(final RtNetlinkRouteMessage routeMsg) {
         final StructNlMsgHdr hdr = routeMsg.getHeader();
         assertNotNull(hdr);
         assertEquals(136, hdr.nlmsg_len);
@@ -97,6 +89,18 @@
         assertEquals((Inet6Address) routeMsg.getGateway(), TEST_IPV6_LINK_LOCAL_GATEWAY);
     }
 
+    @Test
+    public void testParseRtmRouteMessage() {
+        final ByteBuffer byteBuffer = toByteBuffer(RTM_NEWROUTE_HEX);
+        byteBuffer.order(ByteOrder.LITTLE_ENDIAN);  // For testing.
+
+        final NetlinkMessage msg = NetlinkMessage.parse(byteBuffer, NETLINK_ROUTE);
+        assertNotNull(msg);
+        assertTrue(msg instanceof RtNetlinkRouteMessage);
+        final RtNetlinkRouteMessage routeMsg = (RtNetlinkRouteMessage) msg;
+        assertRtmRouteMessage(routeMsg);
+    }
+
     private static final String RTM_NEWROUTE_PACK_HEX =
             "4C000000180000060000000000000000"             // struct nlmsghr
             + "0A400000FC02000100000000"                   // struct rtmsg
@@ -143,7 +147,7 @@
             + "08000400DF020000";                          // RTA_OIF
 
     @Test
-    public void testParseRtmRouteAddress_IPv4MappedIPv6Gateway() {
+    public void testParseRtmRouteMessage_IPv4MappedIPv6Gateway() {
         final ByteBuffer byteBuffer = toByteBuffer(RTM_NEWROUTE_IPV4_MAPPED_IPV6_GATEWAY_HEX);
         byteBuffer.order(ByteOrder.LITTLE_ENDIAN);  // For testing.
         final NetlinkMessage msg = NetlinkMessage.parse(byteBuffer, NETLINK_ROUTE);
@@ -160,7 +164,7 @@
             + "08000400DF020000";                          // RTA_OIF
 
     @Test
-    public void testParseRtmRouteAddress_IPv4MappedIPv6Destination() {
+    public void testParseRtmRouteMessage_IPv4MappedIPv6Destination() {
         final ByteBuffer byteBuffer = toByteBuffer(RTM_NEWROUTE_IPV4_MAPPED_IPV6_DST_HEX);
         byteBuffer.order(ByteOrder.LITTLE_ENDIAN);  // For testing.
         final NetlinkMessage msg = NetlinkMessage.parse(byteBuffer, NETLINK_ROUTE);
@@ -169,6 +173,32 @@
         assertNull(msg);
     }
 
+    // An example of the full RTM_NEWADDR message.
+    private static final String RTM_NEWADDR_HEX =
+            "48000000140000000000000000000000"            // struct nlmsghr
+            + "0A4080FD1E000000"                          // struct ifaddrmsg
+            + "14000100FE800000000000002C415CFFFE096665"  // IFA_ADDRESS
+            + "14000600100E0000201C00002A70000045700000"  // IFA_CACHEINFO
+            + "0800080080000000";                         // IFA_FLAGS
+
+    @Test
+    public void testParseMultipleRtmMessagesInOneByteBuffer() {
+        final ByteBuffer byteBuffer = toByteBuffer(RTM_NEWROUTE_HEX + RTM_NEWADDR_HEX);
+        byteBuffer.order(ByteOrder.LITTLE_ENDIAN);  // For testing.
+
+        // Try to parse the RTM_NEWROUTE message.
+        NetlinkMessage msg = NetlinkMessage.parse(byteBuffer, NETLINK_ROUTE);
+        assertNotNull(msg);
+        assertTrue(msg instanceof RtNetlinkRouteMessage);
+        final RtNetlinkRouteMessage routeMsg = (RtNetlinkRouteMessage) msg;
+        assertRtmRouteMessage(routeMsg);
+
+        // Try to parse the RTM_NEWADDR message.
+        msg = NetlinkMessage.parse(byteBuffer, NETLINK_ROUTE);
+        assertNotNull(msg);
+        assertTrue(msg instanceof RtNetlinkAddressMessage);
+    }
+
     @Test
     public void testToString() {
         final ByteBuffer byteBuffer = toByteBuffer(RTM_NEWROUTE_HEX);
diff --git a/staticlibs/tests/unit/src/com/android/testutils/DeviceInfoUtilsTest.java b/staticlibs/tests/unit/src/com/android/testutils/DeviceInfoUtilsTest.java
new file mode 100644
index 0000000..6f603d5
--- /dev/null
+++ b/staticlibs/tests/unit/src/com/android/testutils/DeviceInfoUtilsTest.java
@@ -0,0 +1,109 @@
+/*
+ * 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.
+ */
+
+package com.android.testutils;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertTrue;
+
+import androidx.test.filters.SmallTest;
+
+import org.junit.Test;
+
+@SmallTest
+public final class DeviceInfoUtilsTest {
+    /**
+     * Verifies that version string compare logic returns expected result for various cases.
+     * Note that only major and minor number are compared.
+     */
+    @Test
+    public void testMajorMinorVersionCompare() {
+        assertEquals(0, DeviceInfoUtils.compareMajorMinorVersion("4.8.1", "4.8"));
+        assertEquals(1, DeviceInfoUtils.compareMajorMinorVersion("4.9", "4.8.1"));
+        assertEquals(1, DeviceInfoUtils.compareMajorMinorVersion("5.0", "4.8"));
+        assertEquals(1, DeviceInfoUtils.compareMajorMinorVersion("5", "4.8"));
+        assertEquals(0, DeviceInfoUtils.compareMajorMinorVersion("5", "5.0"));
+        assertEquals(1, DeviceInfoUtils.compareMajorMinorVersion("5-beta1", "4.8"));
+        assertEquals(0, DeviceInfoUtils.compareMajorMinorVersion("4.8.0.0", "4.8"));
+        assertEquals(0, DeviceInfoUtils.compareMajorMinorVersion("4.8-RC1", "4.8"));
+        assertEquals(0, DeviceInfoUtils.compareMajorMinorVersion("4.8", "4.8"));
+        assertEquals(-1, DeviceInfoUtils.compareMajorMinorVersion("3.10", "4.8.0"));
+        assertEquals(-1, DeviceInfoUtils.compareMajorMinorVersion("4.7.10.10", "4.8"));
+    }
+
+    @Test
+    public void testGetMajorMinorSubminorVersion() throws Exception {
+        final DeviceInfoUtils.KVersion expected = new DeviceInfoUtils.KVersion(4, 19, 220);
+        assertEquals(expected, DeviceInfoUtils.getMajorMinorSubminorVersion("4.19.220"));
+        assertEquals(expected, DeviceInfoUtils.getMajorMinorSubminorVersion("4.19.220.50"));
+        assertEquals(expected, DeviceInfoUtils.getMajorMinorSubminorVersion(
+                "4.19.220-g500ede0aed22-ab8272303"));
+
+        final DeviceInfoUtils.KVersion expected2 = new DeviceInfoUtils.KVersion(5, 17, 0);
+        assertEquals(expected2, DeviceInfoUtils.getMajorMinorSubminorVersion("5.17"));
+        assertEquals(expected2, DeviceInfoUtils.getMajorMinorSubminorVersion("5.17."));
+        assertEquals(expected2, DeviceInfoUtils.getMajorMinorSubminorVersion("5.17.beta"));
+        assertEquals(expected2, DeviceInfoUtils.getMajorMinorSubminorVersion(
+                "5.17-rc6-g52099515ca00-ab8032400"));
+
+        final DeviceInfoUtils.KVersion invalid = new DeviceInfoUtils.KVersion(0, 0, 0);
+        assertEquals(invalid, DeviceInfoUtils.getMajorMinorSubminorVersion(""));
+        assertEquals(invalid, DeviceInfoUtils.getMajorMinorSubminorVersion("4"));
+        assertEquals(invalid, DeviceInfoUtils.getMajorMinorSubminorVersion("4."));
+        assertEquals(invalid, DeviceInfoUtils.getMajorMinorSubminorVersion("4-beta"));
+        assertEquals(invalid, DeviceInfoUtils.getMajorMinorSubminorVersion("1.x.1"));
+        assertEquals(invalid, DeviceInfoUtils.getMajorMinorSubminorVersion("x.1.1"));
+    }
+
+    @Test
+    public void testVersion() throws Exception {
+        final DeviceInfoUtils.KVersion v1 = new DeviceInfoUtils.KVersion(4, 8, 1);
+        final DeviceInfoUtils.KVersion v2 = new DeviceInfoUtils.KVersion(4, 8, 1);
+        final DeviceInfoUtils.KVersion v3 = new DeviceInfoUtils.KVersion(4, 8, 2);
+        final DeviceInfoUtils.KVersion v4 = new DeviceInfoUtils.KVersion(4, 9, 1);
+        final DeviceInfoUtils.KVersion v5 = new DeviceInfoUtils.KVersion(5, 8, 1);
+
+        assertEquals(v1, v2);
+        assertNotEquals(v1, v3);
+        assertNotEquals(v1, v4);
+        assertNotEquals(v1, v5);
+
+        assertEquals(0, v1.compareTo(v2));
+        assertEquals(-1, v1.compareTo(v3));
+        assertEquals(1, v3.compareTo(v1));
+        assertEquals(-1, v1.compareTo(v4));
+        assertEquals(1, v4.compareTo(v1));
+        assertEquals(-1, v1.compareTo(v5));
+        assertEquals(1, v5.compareTo(v1));
+
+        assertTrue(v2.isInRange(v1, v5));
+        assertTrue(v3.isInRange(v1, v5));
+        assertTrue(v4.isInRange(v1, v5));
+        assertFalse(v5.isInRange(v1, v5));
+        assertFalse(v1.isInRange(v3, v5));
+        assertFalse(v5.isInRange(v2, v4));
+
+        assertTrue(v2.isAtLeast(v1));
+        assertTrue(v3.isAtLeast(v1));
+        assertTrue(v4.isAtLeast(v1));
+        assertTrue(v5.isAtLeast(v1));
+        assertFalse(v1.isAtLeast(v3));
+        assertFalse(v1.isAtLeast(v4));
+        assertFalse(v1.isAtLeast(v5));
+    }
+}
diff --git a/staticlibs/testutils/devicetests/com/android/testutils/DevSdkIgnoreRule.kt b/staticlibs/testutils/devicetests/com/android/testutils/DevSdkIgnoreRule.kt
index 8b58e71..6a073ea 100644
--- a/staticlibs/testutils/devicetests/com/android/testutils/DevSdkIgnoreRule.kt
+++ b/staticlibs/testutils/devicetests/com/android/testutils/DevSdkIgnoreRule.kt
@@ -17,16 +17,21 @@
 package com.android.testutils
 
 import android.os.Build
+import androidx.test.InstrumentationRegistry
 import com.android.modules.utils.build.SdkLevel
 import kotlin.test.fail
 import org.junit.Assume.assumeTrue
 import org.junit.rules.TestRule
 import org.junit.runner.Description
 import org.junit.runners.model.Statement
+import java.util.regex.Pattern
 
 // TODO: Remove it when Build.VERSION_CODES.SC_V2 is available
 const val SC_V2 = 32
 
+private val MAX_TARGET_SDK_ANNOTATION_RE = Pattern.compile("MaxTargetSdk([0-9]+)$")
+private val targetSdk = InstrumentationRegistry.getContext().applicationInfo.targetSdkVersion
+
 /**
  * Returns true if the development SDK version of the device is in the provided range.
  *
@@ -67,6 +72,14 @@
     }
 }
 
+private fun getMaxTargetSdk(description: Description): Int? {
+    return description.annotations.firstNotNullOfOrNull {
+        MAX_TARGET_SDK_ANNOTATION_RE.matcher(it::class.simpleName).let { m ->
+            if (m.find()) m.group(1).toIntOrNull() else null
+        }
+    }
+}
+
 /**
  * A test rule to ignore tests based on the development SDK level.
  *
@@ -108,11 +121,17 @@
             val ignoreAfter = description.getAnnotation(IgnoreAfter::class.java)
             val ignoreUpTo = description.getAnnotation(IgnoreUpTo::class.java)
 
-            val message = "Skipping test for build ${Build.VERSION.CODENAME} " +
+            val devSdkMessage = "Skipping test for build ${Build.VERSION.CODENAME} " +
                     "with SDK ${Build.VERSION.SDK_INT}"
-            assumeTrue(message, isDevSdkInRange(ignoreClassUpTo, ignoreClassAfter))
-            assumeTrue(message, isDevSdkInRange(ignoreUpTo?.value, ignoreAfter?.value))
+            assumeTrue(devSdkMessage, isDevSdkInRange(ignoreClassUpTo, ignoreClassAfter))
+            assumeTrue(devSdkMessage, isDevSdkInRange(ignoreUpTo?.value, ignoreAfter?.value))
+
+            val maxTargetSdk = getMaxTargetSdk(description)
+            if (maxTargetSdk != null) {
+                assumeTrue("Skipping test, target SDK $targetSdk greater than $maxTargetSdk",
+                        targetSdk <= maxTargetSdk)
+            }
             base.evaluate()
         }
     }
-}
\ No newline at end of file
+}
diff --git a/staticlibs/testutils/devicetests/com/android/testutils/DeviceInfoUtils.java b/staticlibs/testutils/devicetests/com/android/testutils/DeviceInfoUtils.java
new file mode 100644
index 0000000..1925b55
--- /dev/null
+++ b/staticlibs/testutils/devicetests/com/android/testutils/DeviceInfoUtils.java
@@ -0,0 +1,160 @@
+/*
+ * 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.
+ */
+
+package com.android.testutils;
+
+import android.text.TextUtils;
+import android.util.Pair;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * Utilities for device information.
+ */
+public class DeviceInfoUtils {
+    /**
+     * Class for a three-part kernel version number.
+     */
+    public static class KVersion {
+        public final int major;
+        public final int minor;
+        public final int sub;
+
+        public KVersion(int major, int minor, int sub) {
+            this.major = major;
+            this.minor = minor;
+            this.sub = sub;
+        }
+
+        /**
+         * Compares with other version numerically.
+         *
+         * @param  other the other version to compare
+         * @return the value 0 if this == other;
+         *         a value less than 0 if this < other and
+         *         a value greater than 0 if this > other.
+         */
+        public int compareTo(final KVersion other) {
+            int res = Integer.compare(this.major, other.major);
+            if (res == 0) {
+                res = Integer.compare(this.minor, other.minor);
+            }
+            if (res == 0) {
+                res = Integer.compare(this.sub, other.sub);
+            }
+            return res;
+        }
+
+        /**
+         * At least satisfied with the given version.
+         *
+         * @param  from the start version to compare
+         * @return return true if this version is at least satisfied with the given version.
+         *         otherwise, return false.
+         */
+        public boolean isAtLeast(final KVersion from) {
+            return compareTo(from) >= 0;
+        }
+
+        /**
+         * Falls within the given range [from, to).
+         *
+         * @param  from the start version to compare
+         * @param  to   the end version to compare
+         * @return return true if this version falls within the given range.
+         *         otherwise, return false.
+         */
+        public boolean isInRange(final KVersion from, final KVersion to) {
+            return isAtLeast(from) && !isAtLeast(to);
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (!(o instanceof KVersion)) return false;
+            KVersion that = (KVersion) o;
+            return this.major == that.major
+                    && this.minor == that.minor
+                    && this.sub == that.sub;
+        }
+    };
+
+    /**
+     * Get a two-part kernel version number (major and minor) from a given string.
+     *
+     * TODO: use class KVersion.
+     */
+    private static Pair<Integer, Integer> getMajorMinorVersion(String version) {
+        // Only gets major and minor number of the version string.
+        final Pattern versionPattern = Pattern.compile("^(\\d+)(\\.(\\d+))?.*");
+        final Matcher m = versionPattern.matcher(version);
+        if (m.matches()) {
+            final int major = Integer.parseInt(m.group(1));
+            final int minor = TextUtils.isEmpty(m.group(3)) ? 0 : Integer.parseInt(m.group(3));
+            return new Pair<>(major, minor);
+        } else {
+            return new Pair<>(0, 0);
+        }
+    }
+
+    /**
+     * Compares two version strings numerically. Compare only major and minor number of the
+     * version string. The version comparison uses #Integer.compare. Possible version
+     * 5, 5.10, 5-beta1, 4.8-RC1, 4.7.10.10 and so on.
+     *
+     * @param  s1 the first version string to compare
+     * @param  s2 the second version string to compare
+     * @return the value 0 if s1 == s2;
+     *         a value less than 0 if s1 < s2 and
+     *         a value greater than 0 if s1 > s2.
+     *
+     * TODO: use class KVersion.
+     */
+    public static int compareMajorMinorVersion(final String s1, final String s2) {
+        final Pair<Integer, Integer> v1 = getMajorMinorVersion(s1);
+        final Pair<Integer, Integer> v2 = getMajorMinorVersion(s2);
+
+        if (v1.first == v2.first) {
+            return Integer.compare(v1.second, v2.second);
+        } else {
+            return Integer.compare(v1.first, v2.first);
+        }
+    }
+
+    /**
+     * Get a three-part kernel version number (major, minor and subminor) from a given string.
+     * Any version string must at least have major and minor number. If the subminor number can't
+     * be parsed from string. Assign zero as subminor number. Invalid version is treated as
+     * version 0.0.0.
+     */
+    public static KVersion getMajorMinorSubminorVersion(final String version) {
+        // The kernel version is a three-part version number (major, minor and subminor). Get
+        // the three-part version numbers and discard the remaining stuff if any.
+        // For example:
+        //   4.19.220-g500ede0aed22-ab8272303 --> 4.19.220
+        //   5.17-rc6-g52099515ca00-ab8032400 --> 5.17.0
+        final Pattern versionPattern = Pattern.compile("^(\\d+)\\.(\\d+)(\\.(\\d+))?.*");
+        final Matcher m = versionPattern.matcher(version);
+        if (m.matches()) {
+            final int major = Integer.parseInt(m.group(1));
+            final int minor = Integer.parseInt(m.group(2));
+            final int sub = TextUtils.isEmpty(m.group(4)) ? 0 : Integer.parseInt(m.group(4));
+            return new KVersion(major, minor, sub);
+        } else {
+            return new KVersion(0, 0, 0);
+        }
+    }
+}
diff --git a/staticlibs/testutils/devicetests/com/android/testutils/TestNetworkTracker.kt b/staticlibs/testutils/devicetests/com/android/testutils/TestNetworkTracker.kt
index 40731ea..bdea6c7 100644
--- a/staticlibs/testutils/devicetests/com/android/testutils/TestNetworkTracker.kt
+++ b/staticlibs/testutils/devicetests/com/android/testutils/TestNetworkTracker.kt
@@ -23,6 +23,7 @@
 import android.net.Network
 import android.net.NetworkCapabilities
 import android.net.NetworkRequest
+import android.net.LinkProperties
 import android.net.TestNetworkInterface
 import android.net.TestNetworkManager
 import android.os.Binder
@@ -32,6 +33,7 @@
 
 /**
  * Create a test network based on a TUN interface with a LinkAddress.
+ * TODO: remove this function after fixing all the callers.
  *
  * This method will block until the test network is available. Requires
  * [android.Manifest.permission.CHANGE_NETWORK_STATE] and
@@ -42,11 +44,13 @@
     interfaceAddr: LinkAddress,
     setupTimeoutMs: Long = 10_000L
 ): TestNetworkTracker {
-    return initTestNetwork(context, listOf(interfaceAddr), setupTimeoutMs)
+    val lp = LinkProperties()
+    lp.addLinkAddress(interfaceAddr)
+    return initTestNetwork(context, lp, setupTimeoutMs)
 }
 
 /**
- * Create a test network based on a TUN interface with giving LinkAddress list.
+ * Create a test network based on a TUN interface
  *
  * This method will block until the test network is available. Requires
  * [android.Manifest.permission.CHANGE_NETWORK_STATE] and
@@ -54,13 +58,14 @@
  */
 fun initTestNetwork(
     context: Context,
-    linkAddrs: List<LinkAddress>,
+    lp: LinkProperties,
     setupTimeoutMs: Long = 10_000L
 ): TestNetworkTracker {
     val tnm = context.getSystemService(TestNetworkManager::class.java)
-    val iface = if (isAtLeastS()) tnm.createTunInterface(linkAddrs)
-            else tnm.createTunInterface(linkAddrs.toTypedArray())
-    return TestNetworkTracker(context, iface, tnm, setupTimeoutMs)
+    val iface = if (isAtLeastS()) tnm.createTunInterface(lp.getLinkAddresses())
+            else tnm.createTunInterface(lp.getLinkAddresses().toTypedArray())
+    lp.setInterfaceName(iface.interfaceName)
+    return TestNetworkTracker(context, iface, tnm, lp, setupTimeoutMs)
 }
 
 /**
@@ -72,6 +77,7 @@
     val context: Context,
     val iface: TestNetworkInterface,
     val tnm: TestNetworkManager,
+    val lp: LinkProperties,
     setupTimeoutMs: Long
 ) {
     private val cm = context.getSystemService(ConnectivityManager::class.java)
@@ -98,7 +104,7 @@
         cm.requestNetwork(networkRequest, networkCallback)
 
         try {
-            tnm.setupTestNetwork(iface.interfaceName, binder)
+            tnm.setupTestNetwork(lp, true /* isMetered */, binder)
             network = networkFuture.get(setupTimeoutMs, TimeUnit.MILLISECONDS)
         } catch (e: Throwable) {
             teardown()
@@ -112,4 +118,4 @@
         cm.unregisterNetworkCallback(networkCallback)
         tnm.teardownTestNetwork(network)
     }
-}
\ No newline at end of file
+}
diff --git a/staticlibs/testutils/devicetests/com/android/testutils/filters/CtsNetTestCasesMaxTargetSdk31.kt b/staticlibs/testutils/devicetests/com/android/testutils/filters/CtsNetTestCasesMaxTargetSdk31.kt
new file mode 100644
index 0000000..be0103d
--- /dev/null
+++ b/staticlibs/testutils/devicetests/com/android/testutils/filters/CtsNetTestCasesMaxTargetSdk31.kt
@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2020 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 com.android.testutils.filters
+
+/**
+ * Only run this test in the CtsNetTestCasesMaxTargetSdk31 suite.
+ */
+annotation class CtsNetTestCasesMaxTargetSdk31(val reason: String)