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Diffstat (limited to 'common/testutils/devicetests/com/android/testutils/PacketReflector.java')
-rw-r--r--common/testutils/devicetests/com/android/testutils/PacketReflector.java264
1 files changed, 0 insertions, 264 deletions
diff --git a/common/testutils/devicetests/com/android/testutils/PacketReflector.java b/common/testutils/devicetests/com/android/testutils/PacketReflector.java
deleted file mode 100644
index 69392d44..00000000
--- a/common/testutils/devicetests/com/android/testutils/PacketReflector.java
+++ /dev/null
@@ -1,264 +0,0 @@
-/*
- * 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 android.annotation.NonNull;
-import android.net.TestNetworkInterface;
-import android.system.ErrnoException;
-import android.system.Os;
-import android.util.Log;
-
-import java.io.FileDescriptor;
-import java.io.IOException;
-import java.util.Objects;
-
-/**
- * A class that echoes packets received on a {@link TestNetworkInterface} back to itself.
- *
- * For testing purposes, sometimes a mocked environment to simulate a simple echo from the
- * server side is needed. This is particularly useful if the test, e.g. VpnTest, is
- * heavily relying on the outside world.
- *
- * This class reads packets from the {@link FileDescriptor} of a {@link TestNetworkInterface}, and:
- * 1. For TCP and UDP packets, simply swaps the source address and the destination
- * address, then send it back to the {@link FileDescriptor}.
- * 2. For ICMP ping packets, composes a ping reply and sends it back to the sender.
- * 3. Ignore all other packets.
- */
-public class PacketReflector extends Thread {
-
- static final int IPV4_HEADER_LENGTH = 20;
- static final int IPV6_HEADER_LENGTH = 40;
-
- static final int IPV4_ADDR_OFFSET = 12;
- static final int IPV6_ADDR_OFFSET = 8;
- static final int IPV4_ADDR_LENGTH = 4;
- static final int IPV6_ADDR_LENGTH = 16;
-
- static final int IPV4_PROTO_OFFSET = 9;
- static final int IPV6_PROTO_OFFSET = 6;
-
- static final byte IPPROTO_ICMP = 1;
- static final byte IPPROTO_TCP = 6;
- static final byte IPPROTO_UDP = 17;
- private static final byte IPPROTO_ICMPV6 = 58;
-
- private static final int ICMP_HEADER_LENGTH = 8;
- static final int TCP_HEADER_LENGTH = 20;
- static final int UDP_HEADER_LENGTH = 8;
-
- private static final byte ICMP_ECHO = 8;
- private static final byte ICMP_ECHOREPLY = 0;
-
- private static String TAG = "PacketReflector";
-
- @NonNull
- private final FileDescriptor mFd;
- @NonNull
- private final byte[] mBuf;
-
- /**
- * Construct a {@link PacketReflector} from the given {@code fd} of
- * a {@link TestNetworkInterface}.
- *
- * @param fd {@link FileDescriptor} to read/write packets.
- * @param mtu MTU of the test network.
- */
- public PacketReflector(@NonNull FileDescriptor fd, int mtu) {
- super("PacketReflector");
- mFd = Objects.requireNonNull(fd);
- mBuf = new byte[mtu];
- }
-
- private static void swapBytes(@NonNull 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(@NonNull 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(@NonNull 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(@NonNull 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(@NonNull 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 = PacketReflectorUtil.readPacket(mFd, 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(@NonNull byte[] buf, int len) {
- try {
- Os.write(mFd, buf, 0, len);
- } catch (ErrnoException | IOException e) {
- Log.e(TAG, "Error writing packet: " + e.getMessage());
- }
- }
-
- // Reads one packet from our mFd, and possibly writes the packet back.
- private void processPacket() {
- int len = PacketReflectorUtil.readPacket(mFd, mBuf);
- if (len < 1) {
- // Usually happens when socket read is being interrupted, e.g. stopping PacketReflector.
- return;
- }
-
- int version = mBuf[0] >> 4;
- int protoPos, hdrLen;
- if (version == 4) {
- hdrLen = IPV4_HEADER_LENGTH;
- protoPos = IPV4_PROTO_OFFSET;
- } else if (version == 6) {
- hdrLen = IPV6_HEADER_LENGTH;
- protoPos = IPV6_PROTO_OFFSET;
- } else {
- throw new IllegalStateException("Unexpected version: " + version);
- }
-
- if (len < hdrLen) {
- throw new IllegalStateException("Unexpected buffer length: " + len);
- }
-
- byte proto = mBuf[protoPos];
- switch (proto) {
- case IPPROTO_ICMP:
- // fall through
- 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, "starting fd=" + mFd + " valid=" + mFd.valid());
- while (!interrupted() && mFd.valid()) {
- processPacket();
- }
- Log.i(TAG, "exiting fd=" + mFd + " valid=" + mFd.valid());
- }
-}
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-23 18:45:50 +0000