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/*
* Copyright © 2017-2023 WireGuard LLC. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0
*/
package com.wireguard.android.backend;
import android.content.Context;
import android.util.Log;
import android.util.Pair;
import com.wireguard.android.backend.BackendException.Reason;
import com.wireguard.android.backend.Tunnel.State;
import com.wireguard.android.util.RootShell;
import com.wireguard.android.util.ToolsInstaller;
import com.wireguard.config.Config;
import com.wireguard.crypto.Key;
import com.wireguard.util.NonNullForAll;
import java.io.File;
import java.io.FileOutputStream;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import androidx.annotation.Nullable;
/**
* Implementation of {@link Backend} that uses the kernel module and {@code wg-quick} to provide
* WireGuard tunnels.
*/
@NonNullForAll
public final class WgQuickBackend implements Backend {
private static final String TAG = "WireGuard/WgQuickBackend";
private final File localTemporaryDir;
private final RootShell rootShell;
private final Map<Tunnel, Config> runningConfigs = new HashMap<>();
private final ToolsInstaller toolsInstaller;
private boolean multipleTunnels;
public WgQuickBackend(final Context context, final RootShell rootShell, final ToolsInstaller toolsInstaller) {
localTemporaryDir = new File(context.getCacheDir(), "tmp");
this.rootShell = rootShell;
this.toolsInstaller = toolsInstaller;
}
public static boolean hasKernelSupport() {
return new File("/sys/module/wireguard").exists();
}
@Override
public Set<String> getRunningTunnelNames() {
final List<String> output = new ArrayList<>();
// Don't throw an exception here or nothing will show up in the UI.
try {
toolsInstaller.ensureToolsAvailable();
if (rootShell.run(output, "wg show interfaces") != 0 || output.isEmpty())
return Collections.emptySet();
} catch (final Exception e) {
Log.w(TAG, "Unable to enumerate running tunnels", e);
return Collections.emptySet();
}
// wg puts all interface names on the same line. Split them into separate elements.
return Set.of(output.get(0).split(" "));
}
@Override
public State getState(final Tunnel tunnel) {
return getRunningTunnelNames().contains(tunnel.getName()) ? State.UP : State.DOWN;
}
@Override
public Statistics getStatistics(final Tunnel tunnel) {
final Statistics stats = new Statistics();
final Collection<String> output = new ArrayList<>();
try {
if (rootShell.run(output, String.format("wg show '%s' transfer", tunnel.getName())) != 0)
return stats;
} catch (final Exception ignored) {
return stats;
}
for (final String line : output) {
final String[] parts = line.split("\\t");
if (parts.length != 3)
continue;
try {
stats.add(Key.fromBase64(parts[0]), Long.parseLong(parts[1]), Long.parseLong(parts[2]));
} catch (final Exception ignored) {
}
}
return stats;
}
@Override
public String getVersion() throws Exception {
final List<String> output = new ArrayList<>();
if (rootShell.run(output, "cat /sys/module/wireguard/version") != 0 || output.isEmpty())
throw new BackendException(Reason.UNKNOWN_KERNEL_MODULE_NAME);
return output.get(0);
}
public void setMultipleTunnels(final boolean on) {
multipleTunnels = on;
}
@Override
public State setState(final Tunnel tunnel, State state, @Nullable final Config config) throws Exception {
final State originalState = getState(tunnel);
final Config originalConfig = runningConfigs.get(tunnel);
final Map<Tunnel, Config> runningConfigsSnapshot = new HashMap<>(runningConfigs);
if (state == State.TOGGLE)
state = originalState == State.UP ? State.DOWN : State.UP;
if ((state == State.UP && originalState == State.UP && originalConfig != null && originalConfig == config) ||
(state == State.DOWN && originalState == State.DOWN))
return originalState;
if (state == State.UP) {
toolsInstaller.ensureToolsAvailable();
if (!multipleTunnels && originalState == State.DOWN) {
final List<Pair<Tunnel, Config>> rewind = new LinkedList<>();
try {
for (final Map.Entry<Tunnel, Config> entry : runningConfigsSnapshot.entrySet()) {
setStateInternal(entry.getKey(), entry.getValue(), State.DOWN);
rewind.add(Pair.create(entry.getKey(), entry.getValue()));
}
} catch (final Exception e) {
try {
for (final Pair<Tunnel, Config> entry : rewind) {
setStateInternal(entry.first, entry.second, State.UP);
}
} catch (final Exception ignored) {
}
throw e;
}
}
if (originalState == State.UP)
setStateInternal(tunnel, originalConfig == null ? config : originalConfig, State.DOWN);
try {
setStateInternal(tunnel, config, State.UP);
} catch (final Exception e) {
try {
if (originalState == State.UP && originalConfig != null) {
setStateInternal(tunnel, originalConfig, State.UP);
}
if (!multipleTunnels && originalState == State.DOWN) {
for (final Map.Entry<Tunnel, Config> entry : runningConfigsSnapshot.entrySet()) {
setStateInternal(entry.getKey(), entry.getValue(), State.UP);
}
}
} catch (final Exception ignored) {
}
throw e;
}
} else if (state == State.DOWN) {
setStateInternal(tunnel, originalConfig == null ? config : originalConfig, State.DOWN);
}
return state;
}
private void setStateInternal(final Tunnel tunnel, @Nullable final Config config, final State state) throws Exception {
Log.i(TAG, "Bringing tunnel " + tunnel.getName() + ' ' + state);
Objects.requireNonNull(config, "Trying to set state up with a null config");
final File tempFile = new File(localTemporaryDir, tunnel.getName() + ".conf");
try (final FileOutputStream stream = new FileOutputStream(tempFile, false)) {
stream.write(config.toWgQuickString().getBytes(StandardCharsets.UTF_8));
}
String command = String.format("wg-quick %s '%s'",
state.toString().toLowerCase(Locale.ENGLISH), tempFile.getAbsolutePath());
if (state == State.UP)
command = "cat /sys/module/wireguard/version && " + command;
final int result = rootShell.run(null, command);
// noinspection ResultOfMethodCallIgnored
tempFile.delete();
if (result != 0)
throw new BackendException(Reason.WG_QUICK_CONFIG_ERROR_CODE, result);
if (state == State.UP)
runningConfigs.put(tunnel, config);
else
runningConfigs.remove(tunnel);
tunnel.onStateChange(state);
}
}
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