Add utilities to test tap interface networks
Add an ArpResponder based on a generic PacketResponder class, and a
TestHttpServer based on NanoHttpd.
Test: tests based on these utilities
Bug: 160617623
Bug: 160656765
Change-Id: I50b872a8b23e8df997e8f62f0adc7c0256c4d74d
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)
+ }
+}
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