diff options
Diffstat (limited to 'common/testutils/devicetests/com/android/testutils/TestDnsServer.kt')
| -rw-r--r-- | common/testutils/devicetests/com/android/testutils/TestDnsServer.kt | 173 |
1 files changed, 0 insertions, 173 deletions
diff --git a/common/testutils/devicetests/com/android/testutils/TestDnsServer.kt b/common/testutils/devicetests/com/android/testutils/TestDnsServer.kt deleted file mode 100644 index e1b771b2..00000000 --- a/common/testutils/devicetests/com/android/testutils/TestDnsServer.kt +++ /dev/null @@ -1,173 +0,0 @@ -/* - * 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.net.Network -import android.util.Log -import com.android.internal.annotations.GuardedBy -import com.android.internal.annotations.VisibleForTesting -import com.android.internal.annotations.VisibleForTesting.Visibility.PRIVATE -import com.android.net.module.util.DnsPacket -import java.net.DatagramPacket -import java.net.DatagramSocket -import java.net.InetAddress -import java.net.InetSocketAddress -import java.net.SocketAddress -import java.net.SocketException -import java.util.ArrayList - -private const val TAG = "TestDnsServer" -private const val VDBG = true -@VisibleForTesting(visibility = PRIVATE) -const val MAX_BUF_SIZE = 8192 - -/** - * A simple implementation of Dns Server that can be bound on specific address and Network. - * - * The caller should use start() to make the server start a new thread to receive DNS queries - * on the bound address, [isAlive] to check status, and stop() for stopping. - * The server allows user to manipulate the records to be answered through - * [setAnswer] at runtime. - * - * This server runs on its own thread. Please make sure writing the query to the socket - * happens-after using [setAnswer] to guarantee the correct answer is returned. If possible, - * use [setAnswer] before calling [start] for simplicity. - */ -class TestDnsServer(network: Network, addr: InetSocketAddress) { - enum class Status { - NOT_STARTED, STARTED, STOPPED - } - @GuardedBy("thread") - private var status: Status = Status.NOT_STARTED - private val thread = ReceivingThread() - private val socket = DatagramSocket(addr).also { network.bindSocket(it) } - private val ansProvider = DnsAnswerProvider() - - // The buffer to store the received packet. They are being reused for - // efficiency and it's fine because they are only ever accessed - // on the server thread in a sequential manner. - private val buffer = ByteArray(MAX_BUF_SIZE) - private val packet = DatagramPacket(buffer, buffer.size) - - fun setAnswer(hostname: String, answer: List<InetAddress>) = - ansProvider.setAnswer(hostname, answer) - - private fun processPacket() { - // Blocking read and try construct a DnsQueryPacket object. - socket.receive(packet) - val q = DnsQueryPacket(packet.data) - handleDnsQuery(q, packet.socketAddress) - } - - // TODO: Add support to reply some error with a DNS reply packet with failure RCODE. - private fun handleDnsQuery(q: DnsQueryPacket, src: SocketAddress) { - val queryRecords = q.queryRecords - if (queryRecords.size != 1) { - throw IllegalArgumentException( - "Expected one dns query record but got ${queryRecords.size}" - ) - } - val answerRecords = queryRecords[0].let { ansProvider.getAnswer(it.dName, it.nsType) } - - if (VDBG) { - Log.v(TAG, "handleDnsPacket: " + - queryRecords.map { "${it.dName},${it.nsType}" }.joinToString() + - " ansCount=${answerRecords.size} socketAddress=$src") - } - - val bytes = q.getAnswerPacket(answerRecords).bytes - val reply = DatagramPacket(bytes, bytes.size, src) - socket.send(reply) - } - - fun start() { - synchronized(thread) { - if (status != Status.NOT_STARTED) { - throw IllegalStateException("unexpected status: $status") - } - thread.start() - status = Status.STARTED - } - } - fun stop() { - synchronized(thread) { - if (status != Status.STARTED) { - throw IllegalStateException("unexpected status: $status") - } - // The thread needs to be interrupted before closing the socket to prevent a data - // race where the thread tries to read from the socket while it's being closed. - // DatagramSocket is not thread-safe and running both concurrently can end up in - // getPort() returning -1 after it's been checked not to, resulting in a crash by - // IllegalArgumentException inside the DatagramSocket implementation. - thread.interrupt() - socket.close() - thread.join() - status = Status.STOPPED - } - } - val isAlive get() = thread.isAlive - val port get() = socket.localPort - - inner class ReceivingThread : Thread() { - override fun run() { - while (!interrupted() && !socket.isClosed) { - try { - processPacket() - } catch (e: InterruptedException) { - // The caller terminated the server, exit. - break - } catch (e: SocketException) { - // The caller terminated the server, exit. - break - } - } - Log.i(TAG, "exiting socket={$socket}") - } - } - - @VisibleForTesting(visibility = PRIVATE) - class DnsQueryPacket : DnsPacket { - constructor(data: ByteArray) : super(data) - constructor(header: DnsHeader, qd: List<DnsRecord>, an: List<DnsRecord>) : - super(header, qd, an) - - init { - if (mHeader.isResponse) { - throw ParseException("Not a query packet") - } - } - - val queryRecords: List<DnsRecord> - get() = mRecords[QDSECTION] - - fun getAnswerPacket(ar: List<DnsRecord>): DnsAnswerPacket { - // Set QR bit of flag to 1 for response packet according to RFC 1035 section 4.1.1. - val flags = 1 shl 15 - val qr = ArrayList(mRecords[QDSECTION]) - // Copy the query packet header id to the answer packet as RFC 1035 section 4.1.1. - val header = DnsHeader(mHeader.id, flags, qr.size, ar.size) - return DnsAnswerPacket(header, qr, ar) - } - } - - class DnsAnswerPacket : DnsPacket { - constructor(header: DnsHeader, qr: List<DnsRecord>, ar: List<DnsRecord>) : - super(header, qr, ar) - @VisibleForTesting(visibility = PRIVATE) - constructor(bytes: ByteArray) : super(bytes) - } -} |