diff --git a/staticlibs/testutils/devicetests/com/android/testutils/PacketReflector.java b/staticlibs/testutils/devicetests/com/android/testutils/PacketReflector.java
new file mode 100644
index 0000000..b05bb9b
--- /dev/null
+++ b/staticlibs/testutils/devicetests/com/android/testutils/PacketReflector.java
@@ -0,0 +1,254 @@
+/*
+ * Copyright (C) 2014 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 android.system.OsConstants.ICMP6_ECHO_REPLY;
+import static android.system.OsConstants.ICMP6_ECHO_REQUEST;
+import static android.system.OsConstants.ICMP_ECHO;
+import static android.system.OsConstants.ICMP_ECHOREPLY;
+
+import android.system.ErrnoException;
+import android.system.Os;
+import android.util.Log;
+
+import java.io.FileDescriptor;
+import java.io.IOException;
+
+public class PacketReflector extends Thread {
+
+    private static int IPV4_HEADER_LENGTH = 20;
+    private static int IPV6_HEADER_LENGTH = 40;
+
+    private static int IPV4_ADDR_OFFSET = 12;
+    private static int IPV6_ADDR_OFFSET = 8;
+    private static int IPV4_ADDR_LENGTH = 4;
+    private static int IPV6_ADDR_LENGTH = 16;
+
+    private static int IPV4_PROTO_OFFSET = 9;
+    private static int IPV6_PROTO_OFFSET = 6;
+
+    private static final byte IPPROTO_ICMP = 1;
+    private static final byte IPPROTO_TCP = 6;
+    private static final byte IPPROTO_UDP = 17;
+    private static final byte IPPROTO_ICMPV6 = 58;
+
+    private static int ICMP_HEADER_LENGTH = 8;
+    private static int TCP_HEADER_LENGTH = 20;
+    private static int UDP_HEADER_LENGTH = 8;
+
+    private static final byte ICMP_ECHO = 8;
+    private static final byte ICMP_ECHOREPLY = 0;
+
+    private static String TAG = "PacketReflector";
+
+    private FileDescriptor mFd;
+    private byte[] mBuf;
+
+    public PacketReflector(FileDescriptor fd, int mtu) {
+        super("PacketReflector");
+        mFd = fd;
+        mBuf = new byte[mtu];
+    }
+
+    private static void swapBytes(byte[] buf, int pos1, int pos2, int len) {
+        for (int i = 0; i < len; i++) {
+            byte b = buf[pos1 + i];
+            buf[pos1 + i] = buf[pos2 + i];
+            buf[pos2 + i] = b;
+        }
+    }
+
+    private static void swapAddresses(byte[] buf, int version) {
+        int addrPos, addrLen;
+        switch(version) {
+            case 4:
+                addrPos = IPV4_ADDR_OFFSET;
+                addrLen = IPV4_ADDR_LENGTH;
+                break;
+            case 6:
+                addrPos = IPV6_ADDR_OFFSET;
+                addrLen = IPV6_ADDR_LENGTH;
+                break;
+            default:
+                throw new IllegalArgumentException();
+        }
+        swapBytes(buf, addrPos, addrPos + addrLen, addrLen);
+    }
+
+    // Reflect TCP packets: swap the source and destination addresses, but don't change the ports.
+    // This is used by the test to "connect to itself" through the VPN.
+    private void processTcpPacket(byte[] buf, int version, int len, int hdrLen) {
+        if (len < hdrLen + TCP_HEADER_LENGTH) {
+            return;
+        }
+
+        // Swap src and dst IP addresses.
+        swapAddresses(buf, version);
+
+        // Send the packet back.
+        writePacket(buf, len);
+    }
+
+    // Echo UDP packets: swap source and destination addresses, and source and destination ports.
+    // This is used by the test to check that the bytes it sends are echoed back.
+    private void processUdpPacket(byte[] buf, int version, int len, int hdrLen) {
+        if (len < hdrLen + UDP_HEADER_LENGTH) {
+            return;
+        }
+
+        // Swap src and dst IP addresses.
+        swapAddresses(buf, version);
+
+        // Swap dst and src ports.
+        int portOffset = hdrLen;
+        swapBytes(buf, portOffset, portOffset + 2, 2);
+
+        // Send the packet back.
+        writePacket(buf, len);
+    }
+
+    private void processIcmpPacket(byte[] buf, int version, int len, int hdrLen) {
+        if (len < hdrLen + ICMP_HEADER_LENGTH) {
+            return;
+        }
+
+        byte type = buf[hdrLen];
+        if (!(version == 4 && type == ICMP_ECHO) &&
+            !(version == 6 && type == (byte) ICMP6_ECHO_REQUEST)) {
+            return;
+        }
+
+        // Save the ping packet we received.
+        byte[] request = buf.clone();
+
+        // Swap src and dst IP addresses, and send the packet back.
+        // This effectively pings the device to see if it replies.
+        swapAddresses(buf, version);
+        writePacket(buf, len);
+
+        // The device should have replied, and buf should now contain a ping response.
+        int received = readPacket(buf);
+        if (received != len) {
+            Log.i(TAG, "Reflecting ping did not result in ping response: " +
+                       "read=" + received + " expected=" + len);
+            return;
+        }
+
+        byte replyType = buf[hdrLen];
+        if ((type == ICMP_ECHO && replyType != ICMP_ECHOREPLY)
+                || (type == (byte) ICMP6_ECHO_REQUEST && replyType != (byte) ICMP6_ECHO_REPLY)) {
+            Log.i(TAG, "Received unexpected ICMP reply: original " + type
+                    + ", reply " + replyType);
+            return;
+        }
+
+        // Compare the response we got with the original packet.
+        // The only thing that should have changed are addresses, type and checksum.
+        // Overwrite them with the received bytes and see if the packet is otherwise identical.
+        request[hdrLen] = buf[hdrLen];          // Type
+        request[hdrLen + 2] = buf[hdrLen + 2];  // Checksum byte 1.
+        request[hdrLen + 3] = buf[hdrLen + 3];  // Checksum byte 2.
+
+        // Since Linux kernel 4.2, net.ipv6.auto_flowlabels is set by default, and therefore
+        // the request and reply may have different IPv6 flow label: ignore that as well.
+        if (version == 6) {
+            request[1] = (byte)(request[1] & 0xf0 | buf[1] & 0x0f);
+            request[2] = buf[2];
+            request[3] = buf[3];
+        }
+
+        for (int i = 0; i < len; i++) {
+            if (buf[i] != request[i]) {
+                Log.i(TAG, "Received non-matching packet when expecting ping response.");
+                return;
+            }
+        }
+
+        // Now swap the addresses again and reflect the packet. This sends a ping reply.
+        swapAddresses(buf, version);
+        writePacket(buf, len);
+    }
+
+    private void writePacket(byte[] buf, int len) {
+        try {
+            Os.write(mFd, buf, 0, len);
+        } catch (ErrnoException|IOException e) {
+            Log.e(TAG, "Error writing packet: " + e.getMessage());
+        }
+    }
+
+    private int readPacket(byte[] buf) {
+        int len;
+        try {
+            len = Os.read(mFd, buf, 0, buf.length);
+        } catch (ErrnoException|IOException e) {
+            Log.e(TAG, "Error reading packet: " + e.getMessage());
+            len = -1;
+        }
+        return len;
+    }
+
+    // Reads one packet from our mFd, and possibly writes the packet back.
+    private void processPacket() {
+        int len = readPacket(mBuf);
+        if (len < 1) {
+            return;
+        }
+
+        int version = mBuf[0] >> 4;
+        int addrPos, protoPos, hdrLen, addrLen;
+        if (version == 4) {
+            hdrLen = IPV4_HEADER_LENGTH;
+            protoPos = IPV4_PROTO_OFFSET;
+            addrPos = IPV4_ADDR_OFFSET;
+            addrLen = IPV4_ADDR_LENGTH;
+        } else if (version == 6) {
+            hdrLen = IPV6_HEADER_LENGTH;
+            protoPos = IPV6_PROTO_OFFSET;
+            addrPos = IPV6_ADDR_OFFSET;
+            addrLen = IPV6_ADDR_LENGTH;
+        } else {
+            return;
+        }
+
+        if (len < hdrLen) {
+            return;
+        }
+
+        byte proto = mBuf[protoPos];
+        switch (proto) {
+            case IPPROTO_ICMP:
+            case IPPROTO_ICMPV6:
+                processIcmpPacket(mBuf, version, len, hdrLen);
+                break;
+            case IPPROTO_TCP:
+                processTcpPacket(mBuf, version, len, hdrLen);
+                break;
+            case IPPROTO_UDP:
+                processUdpPacket(mBuf, version, len, hdrLen);
+                break;
+        }
+    }
+
+    public void run() {
+        Log.i(TAG, "PacketReflector starting fd=" + mFd + " valid=" + mFd.valid());
+        while (!interrupted() && mFd.valid()) {
+            processPacket();
+        }
+        Log.i(TAG, "PacketReflector exiting fd=" + mFd + " valid=" + mFd.valid());
+    }
+}