diff --git a/staticlibs/Android.bp b/staticlibs/Android.bp
index 4b15b16..f4799f0 100644
--- a/staticlibs/Android.bp
+++ b/staticlibs/Android.bp
@@ -98,6 +98,7 @@
     ],
     static_libs: [
         "androidx.test.ext.junit",
+        "libnanohttpd",
         "net-tests-utils-host-device-common",
         "net-utils-device-common",
     ],
diff --git a/staticlibs/devicetests/com/android/testutils/ArpResponder.kt b/staticlibs/devicetests/com/android/testutils/ArpResponder.kt
new file mode 100644
index 0000000..86631c3
--- /dev/null
+++ b/staticlibs/devicetests/com/android/testutils/ArpResponder.kt
@@ -0,0 +1,60 @@
+/*
+ * 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
+
+import android.net.MacAddress
+import java.net.Inet4Address
+import java.net.InetAddress
+import java.nio.ByteBuffer
+
+private val TYPE_ARP = byteArrayOf(0x08, 0x06)
+// Arp reply header for IPv4 over ethernet
+private val ARP_REPLY_IPV4 = byteArrayOf(0x00, 0x01, 0x08, 0x00, 0x06, 0x04, 0x00, 0x02)
+
+/**
+ * A class that can be used to reply to ARP packets on a [TapPacketReader].
+ */
+class ArpResponder(
+    reader: TapPacketReader,
+    table: Map<Inet4Address, MacAddress>,
+    name: String = ArpResponder::class.java.simpleName
+) : PacketResponder(reader, ArpRequestFilter(), name) {
+    // Copy the map if not already immutable (toMap) to make sure it is not modified
+    private val table = table.toMap()
+
+    override fun replyToPacket(packet: ByteArray, reader: TapPacketReader) {
+        val targetIp = InetAddress.getByAddress(
+                packet.copyFromIndexWithLength(ARP_TARGET_IPADDR_OFFSET, 4))
+                as Inet4Address
+
+        val macAddr = table[targetIp]?.toByteArray() ?: return
+        val senderMac = packet.copyFromIndexWithLength(ARP_SENDER_MAC_OFFSET, 6)
+        reader.sendResponse(ByteBuffer.wrap(
+                // Ethernet header
+                senderMac + macAddr + TYPE_ARP +
+                        // ARP message
+                        ARP_REPLY_IPV4 +
+                        macAddr /* sender MAC */ +
+                        targetIp.address /* sender IP addr */ +
+                        macAddr /* target mac */ +
+                        targetIp.address /* target IP addr */
+        ))
+    }
+}
+
+private fun ByteArray.copyFromIndexWithLength(start: Int, len: Int) =
+        copyOfRange(start, start + len)
diff --git a/staticlibs/devicetests/com/android/testutils/PacketResponder.kt b/staticlibs/devicetests/com/android/testutils/PacketResponder.kt
new file mode 100644
index 0000000..daf29e4
--- /dev/null
+++ b/staticlibs/devicetests/com/android/testutils/PacketResponder.kt
@@ -0,0 +1,74 @@
+/*
+ * 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
+
+import java.util.function.Predicate
+
+private const val POLL_FREQUENCY_MS = 1000L
+
+/**
+ * A class that can be used to reply to packets from a [TapPacketReader].
+ *
+ * A reply thread will be created to reply to incoming packets asynchronously.
+ * The receiver creates a new read head on the [TapPacketReader], to read packets, so it does not
+ * affect packets obtained through [TapPacketReader.popPacket].
+ *
+ * @param reader a [TapPacketReader] to obtain incoming packets and reply to them.
+ * @param packetFilter A filter to apply to incoming packets.
+ * @param name Name to use for the internal responder thread.
+ */
+abstract class PacketResponder(
+    private val reader: TapPacketReader,
+    private val packetFilter: Predicate<ByteArray>,
+    name: String
+) {
+    private val replyThread = ReplyThread(name)
+
+    protected abstract fun replyToPacket(packet: ByteArray, reader: TapPacketReader)
+
+    /**
+     * Start the [PacketResponder].
+     */
+    fun start() {
+        replyThread.start()
+    }
+
+    /**
+     * Stop the [PacketResponder].
+     *
+     * The responder cannot be used anymore after being stopped.
+     */
+    fun stop() {
+        replyThread.interrupt()
+    }
+
+    private inner class ReplyThread(name: String) : Thread(name) {
+        override fun run() {
+            try {
+                // Create a new ReadHead so other packets polled on the reader are not affected
+                val recvPackets = reader.receivedPackets.newReadHead()
+                while (!isInterrupted) {
+                    recvPackets.poll(POLL_FREQUENCY_MS, packetFilter::test)?.let {
+                        replyToPacket(it, reader)
+                    }
+                }
+            } catch (e: InterruptedException) {
+                // Exit gracefully
+            }
+        }
+    }
+}
diff --git a/staticlibs/devicetests/com/android/testutils/TestHttpServer.kt b/staticlibs/devicetests/com/android/testutils/TestHttpServer.kt
new file mode 100644
index 0000000..7aae8e3
--- /dev/null
+++ b/staticlibs/devicetests/com/android/testutils/TestHttpServer.kt
@@ -0,0 +1,86 @@
+/*
+ * 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
+
+import android.net.Uri
+import com.android.net.module.util.ArrayTrackRecord
+import fi.iki.elonen.NanoHTTPD
+
+/**
+ * A minimal HTTP server running on a random available port.
+ *
+ * @param host The host to listen to, or null to listen on all hosts
+ */
+class TestHttpServer(host: String? = null) : NanoHTTPD(host, 0 /* auto-select the port */) {
+    // Map of URL path -> HTTP response code
+    private val responses = HashMap<Request, Response>()
+
+    /**
+     * A record of all requests received by the server since it was started.
+     */
+    val requestsRecord = ArrayTrackRecord<Request>()
+
+    /**
+     * A request received by the test server.
+     */
+    data class Request(
+        val path: String,
+        val method: Method = Method.GET,
+        val queryParameters: String = ""
+    ) {
+        /**
+         * Returns whether the specified [Uri] matches parameters of this request.
+         */
+        fun matches(uri: Uri) = (uri.path ?: "") == path && (uri.query ?: "") == queryParameters
+    }
+
+    /**
+     * Add a response for GET requests with the path and query parameters of the specified [Uri].
+     */
+    fun addResponse(
+        uri: Uri,
+        statusCode: Response.IStatus,
+        locationHeader: String? = null,
+        content: String = ""
+    ) {
+        addResponse(Request(uri.path
+                ?: "", Method.GET, uri.query ?: ""),
+                statusCode, locationHeader, content)
+    }
+
+    /**
+     * Add a response for the given request.
+     */
+    fun addResponse(
+        request: Request,
+        statusCode: Response.IStatus,
+        locationHeader: String? = null,
+        content: String = ""
+    ) {
+        val response = newFixedLengthResponse(statusCode, "text/plain", content)
+        locationHeader?.let { response.addHeader("Location", it) }
+        responses[request] = response
+    }
+
+    override fun serve(session: IHTTPSession): Response {
+        val request = Request(session.uri
+                ?: "", session.method, session.queryParameterString ?: "")
+        requestsRecord.add(request)
+        // Default response is a 404
+        return responses[request] ?: super.serve(session)
+    }
+}
\ No newline at end of file