diff options
| -rw-r--r-- | tests/lib/multivariant/com/android/testutils/PacketFilter.kt | 87 | ||||
| -rw-r--r-- | tests/lib/src/com/android/testutils/TapPacketReader.java | 29 |
2 files changed, 105 insertions, 11 deletions
diff --git a/tests/lib/multivariant/com/android/testutils/PacketFilter.kt b/tests/lib/multivariant/com/android/testutils/PacketFilter.kt new file mode 100644 index 0000000..cd8d6a5 --- /dev/null +++ b/tests/lib/multivariant/com/android/testutils/PacketFilter.kt @@ -0,0 +1,87 @@ +/* + * 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 + +const val ETHER_TYPE_OFFSET = 12 +const val ETHER_HEADER_LENGTH = 14 +const val IPV4_PROTOCOL_OFFSET = ETHER_HEADER_LENGTH + 9 +const val IPV4_CHECKSUM_OFFSET = ETHER_HEADER_LENGTH + 10 +const val IPV4_HEADER_LENGTH = 20 +const val IPV4_UDP_OFFSET = ETHER_HEADER_LENGTH + IPV4_HEADER_LENGTH +const val BOOTP_OFFSET = IPV4_UDP_OFFSET + 8 +const val BOOTP_TID_OFFSET = BOOTP_OFFSET + 4 +const val BOOTP_CLIENT_MAC_OFFSET = BOOTP_OFFSET + 28 +const val DHCP_OPTIONS_OFFSET = BOOTP_OFFSET + 240 + +/** + * A [Predicate] that matches a [ByteArray] if it contains the specified [bytes] at the specified + * [offset]. + */ +class OffsetFilter(val offset: Int, vararg val bytes: Byte) : Predicate<ByteArray> { + override fun test(packet: ByteArray) = + bytes.withIndex().all { it.value == packet[offset + it.index] } +} + +/** + * A [Predicate] that matches ethernet-encapped packets that contain an UDP over IPv4 datagram. + */ +class IPv4UdpFilter : Predicate<ByteArray> { + private val impl = OffsetFilter(ETHER_TYPE_OFFSET, 0x08, 0x00 /* IPv4 */).and( + OffsetFilter(IPV4_PROTOCOL_OFFSET, 17 /* UDP */)) + override fun test(t: ByteArray) = impl.test(t) +} + +/** + * A [Predicate] that matches ethernet-encapped DHCP packets sent from a DHCP client. + */ +class DhcpClientPacketFilter : Predicate<ByteArray> { + private val impl = IPv4UdpFilter() + .and(OffsetFilter(IPV4_UDP_OFFSET /* source port */, 0x00, 0x44 /* 68 */)) + .and(OffsetFilter(IPV4_UDP_OFFSET + 2 /* dest port */, 0x00, 0x43 /* 67 */)) + override fun test(t: ByteArray) = impl.test(t) +} + +/** + * A [Predicate] that matches a [ByteArray] if it contains a ethernet-encapped DHCP packet that + * contains the specified option with the specified [bytes] as value. + */ +class DhcpOptionFilter(val option: Byte, vararg val bytes: Byte) : Predicate<ByteArray> { + override fun test(packet: ByteArray): Boolean { + val option = findDhcpOption(packet, option) ?: return false + return option.contentEquals(bytes) + } +} + +/** + * Find a DHCP option in a packet and return its value, if found. + */ +fun findDhcpOption(packet: ByteArray, option: Byte): ByteArray? = + findOptionOffset(packet, option, DHCP_OPTIONS_OFFSET)?.let { + val optionLen = packet[it + 1] + return packet.copyOfRange(it + 2 /* type, length bytes */, it + 2 + optionLen) + } + +private tailrec fun findOptionOffset(packet: ByteArray, option: Byte, searchOffset: Int): Int? { + if (packet.size <= searchOffset + 2 /* type, length bytes */) return null + + return if (packet[searchOffset] == option) searchOffset else { + val optionLen = packet[searchOffset + 1] + findOptionOffset(packet, option, searchOffset + 2 + optionLen) + } +} diff --git a/tests/lib/src/com/android/testutils/TapPacketReader.java b/tests/lib/src/com/android/testutils/TapPacketReader.java index c68e5a5..e55ed44 100644 --- a/tests/lib/src/com/android/testutils/TapPacketReader.java +++ b/tests/lib/src/com/android/testutils/TapPacketReader.java @@ -19,6 +19,7 @@ package com.android.testutils; import android.net.util.PacketReader; import android.os.Handler; +import androidx.annotation.NonNull; import androidx.annotation.Nullable; import java.io.FileDescriptor; @@ -26,12 +27,16 @@ import java.io.FileOutputStream; import java.io.IOException; import java.nio.ByteBuffer; import java.util.Arrays; -import java.util.concurrent.LinkedBlockingQueue; -import java.util.concurrent.TimeUnit; +import java.util.function.Predicate; + +import kotlin.Lazy; +import kotlin.LazyKt; public class TapPacketReader extends PacketReader { private final FileDescriptor mTapFd; - private final LinkedBlockingQueue<byte[]> mReceivedPackets = new LinkedBlockingQueue<byte[]>(); + private final ArrayTrackRecord<byte[]> mReceivedPackets = new ArrayTrackRecord<>(); + private final Lazy<ArrayTrackRecord<byte[]>.ReadHead> mReadHead = + LazyKt.lazy(mReceivedPackets::newReadHead); public TapPacketReader(Handler h, FileDescriptor tapFd, int maxPacketSize) { super(h, maxPacketSize); @@ -46,23 +51,25 @@ public class TapPacketReader extends PacketReader { @Override protected void handlePacket(byte[] recvbuf, int length) { final byte[] newPacket = Arrays.copyOf(recvbuf, length); - if (!mReceivedPackets.offer(newPacket)) { + if (!mReceivedPackets.add(newPacket)) { throw new AssertionError("More than " + Integer.MAX_VALUE + " packets outstanding!"); } } /** * Get the next packet that was received on the interface. - * */ @Nullable public byte[] popPacket(long timeoutMs) { - try { - return mReceivedPackets.poll(timeoutMs, TimeUnit.MILLISECONDS); - } catch (InterruptedException e) { - // Fall through - } - return null; + return mReadHead.getValue().poll(timeoutMs, packet -> true); + } + + /** + * Get the next packet that was received on the interface and matches the specified filter. + */ + @Nullable + public byte[] popPacket(long timeoutMs, @NonNull Predicate<byte[]> filter) { + return mReadHead.getValue().poll(timeoutMs, filter::test); } public void sendResponse(final ByteBuffer packet) throws IOException { |