wireguard-android/tunnel/src/main/java/com/wireguard/android/backend/GoBackend.java

393 lines
14 KiB
Java

/*
* Copyright © 2017-2019 WireGuard LLC. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0
*/
package com.wireguard.android.backend;
import android.content.Context;
import android.content.Intent;
import android.os.Build;
import android.os.ParcelFileDescriptor;
import android.system.OsConstants;
import android.util.Log;
import com.wireguard.android.backend.BackendException.Reason;
import com.wireguard.android.backend.Tunnel.State;
import com.wireguard.android.util.SharedLibraryLoader;
import com.wireguard.config.Config;
import com.wireguard.config.InetNetwork;
import com.wireguard.config.Peer;
import com.wireguard.crypto.Key;
import com.wireguard.crypto.KeyFormatException;
import com.wireguard.util.NonNullForAll;
import java.net.InetAddress;
import java.util.Collections;
import java.util.Set;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.FutureTask;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import androidx.annotation.Nullable;
import androidx.collection.ArraySet;
/**
* Implementation of {@link Backend} that uses the wireguard-go userspace implementation to provide
* WireGuard tunnels.
*/
@NonNullForAll
public final class GoBackend implements Backend {
private static final String TAG = "WireGuard/GoBackend";
@Nullable private static AlwaysOnCallback alwaysOnCallback;
private static GhettoCompletableFuture<VpnService> vpnService = new GhettoCompletableFuture<>();
private final Context context;
@Nullable private Config currentConfig;
@Nullable private Tunnel currentTunnel;
private int currentTunnelHandle = -1;
/**
* Public constructor for GoBackend.
*
* @param context An Android {@link Context}
*/
public GoBackend(final Context context) {
SharedLibraryLoader.loadSharedLibrary(context, "wg-go");
this.context = context;
}
/**
* Set a {@link AlwaysOnCallback} to be invoked when {@link VpnService} is started by the
* system's Always-On VPN mode.
*
* @param cb Callback to be invoked
*/
public static void setAlwaysOnCallback(final AlwaysOnCallback cb) {
alwaysOnCallback = cb;
}
private static native String wgGetConfig(int handle);
private static native int wgGetSocketV4(int handle);
private static native int wgGetSocketV6(int handle);
private static native void wgTurnOff(int handle);
private static native int wgTurnOn(String ifName, int tunFd, String settings);
private static native String wgVersion();
/**
* Method to get the names of running tunnels.
*
* @return A set of string values denoting names of running tunnels.
*/
@Override
public Set<String> getRunningTunnelNames() {
if (currentTunnel != null) {
final Set<String> runningTunnels = new ArraySet<>();
runningTunnels.add(currentTunnel.getName());
return runningTunnels;
}
return Collections.emptySet();
}
/**
* Get the associated {@link State} for a given {@link Tunnel}.
*
* @param tunnel The tunnel to examine the state of.
* @return {@link State} associated with the given tunnel.
*/
@Override
public State getState(final Tunnel tunnel) {
return currentTunnel == tunnel ? State.UP : State.DOWN;
}
/**
* Get the associated {@link Statistics} for a given {@link Tunnel}.
*
* @param tunnel The tunnel to retrieve statistics for.
* @return {@link Statistics} associated with the given tunnel.
*/
@Override
public Statistics getStatistics(final Tunnel tunnel) {
final Statistics stats = new Statistics();
if (tunnel != currentTunnel) {
return stats;
}
final String config = wgGetConfig(currentTunnelHandle);
Key key = null;
long rx = 0;
long tx = 0;
for (final String line : config.split("\\n")) {
if (line.startsWith("public_key=")) {
if (key != null)
stats.add(key, rx, tx);
rx = 0;
tx = 0;
try {
key = Key.fromHex(line.substring(11));
} catch (final KeyFormatException ignored) {
key = null;
}
} else if (line.startsWith("rx_bytes=")) {
if (key == null)
continue;
try {
rx = Long.parseLong(line.substring(9));
} catch (final NumberFormatException ignored) {
rx = 0;
}
} else if (line.startsWith("tx_bytes=")) {
if (key == null)
continue;
try {
tx = Long.parseLong(line.substring(9));
} catch (final NumberFormatException ignored) {
tx = 0;
}
}
}
if (key != null)
stats.add(key, rx, tx);
return stats;
}
/**
* Get the version of the underlying wireguard-go library.
*
* @return {@link String} value of the version of the wireguard-go library.
*/
@Override
public String getVersion() {
return wgVersion();
}
/**
* Change the state of a given {@link Tunnel}, optionally applying a given {@link Config}.
*
* @param tunnel The tunnel to control the state of.
* @param state The new state for this tunnel. Must be {@code UP}, {@code DOWN}, or
* {@code TOGGLE}.
* @param config The configuration for this tunnel, may be null if state is {@code DOWN}.
* @return {@link State} of the tunnel after state changes are applied.
* @throws Exception Exception raised while changing tunnel state.
*/
@Override
public State setState(final Tunnel tunnel, State state, @Nullable final Config config) throws Exception {
final State originalState = getState(tunnel);
if (state == State.TOGGLE)
state = originalState == State.UP ? State.DOWN : State.UP;
if (state == originalState && tunnel == currentTunnel && config == currentConfig)
return originalState;
if (state == State.UP) {
final Config originalConfig = currentConfig;
final Tunnel originalTunnel = currentTunnel;
if (currentTunnel != null)
setStateInternal(currentTunnel, null, State.DOWN);
try {
setStateInternal(tunnel, config, state);
} catch (final Exception e) {
if (originalTunnel != null)
setStateInternal(originalTunnel, originalConfig, State.UP);
throw e;
}
} else if (state == State.DOWN && tunnel == currentTunnel) {
setStateInternal(tunnel, null, State.DOWN);
}
return getState(tunnel);
}
private void setStateInternal(final Tunnel tunnel, @Nullable final Config config, final State state)
throws Exception {
Log.i(TAG, "Bringing tunnel " + tunnel.getName() + ' ' + state);
if (state == State.UP) {
if (config == null)
throw new BackendException(Reason.TUNNEL_MISSING_CONFIG);
if (VpnService.prepare(context) != null)
throw new BackendException(Reason.VPN_NOT_AUTHORIZED);
final VpnService service;
if (!vpnService.isDone()) {
Log.d(TAG, "Requesting to start VpnService");
context.startService(new Intent(context, VpnService.class));
}
try {
service = vpnService.get(2, TimeUnit.SECONDS);
} catch (final TimeoutException e) {
final Exception be = new BackendException(Reason.UNABLE_TO_START_VPN);
be.initCause(e);
throw be;
}
service.setOwner(this);
if (currentTunnelHandle != -1) {
Log.w(TAG, "Tunnel already up");
return;
}
// Build config
final String goConfig = config.toWgUserspaceString();
// Create the vpn tunnel with android API
final VpnService.Builder builder = service.getBuilder();
builder.setSession(tunnel.getName());
for (final String excludedApplication : config.getInterface().getExcludedApplications())
builder.addDisallowedApplication(excludedApplication);
for (final String includedApplication : config.getInterface().getIncludedApplications())
builder.addAllowedApplication(includedApplication);
for (final InetNetwork addr : config.getInterface().getAddresses())
builder.addAddress(addr.getAddress(), addr.getMask());
for (final InetAddress addr : config.getInterface().getDnsServers())
builder.addDnsServer(addr.getHostAddress());
boolean sawDefaultRoute = false;
for (final Peer peer : config.getPeers()) {
for (final InetNetwork addr : peer.getAllowedIps()) {
if (addr.getMask() == 0)
sawDefaultRoute = true;
builder.addRoute(addr.getAddress(), addr.getMask());
}
}
// "Kill-switch" semantics
if (!(sawDefaultRoute && config.getPeers().size() == 1)) {
builder.allowFamily(OsConstants.AF_INET);
builder.allowFamily(OsConstants.AF_INET6);
}
builder.setMtu(config.getInterface().getMtu().orElse(1280));
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q)
builder.setMetered(false);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M)
service.setUnderlyingNetworks(null);
builder.setBlocking(true);
try (final ParcelFileDescriptor tun = builder.establish()) {
if (tun == null)
throw new BackendException(Reason.TUN_CREATION_ERROR);
Log.d(TAG, "Go backend v" + wgVersion());
currentTunnelHandle = wgTurnOn(tunnel.getName(), tun.detachFd(), goConfig);
}
if (currentTunnelHandle < 0)
throw new BackendException(Reason.GO_ACTIVATION_ERROR_CODE, currentTunnelHandle);
currentTunnel = tunnel;
currentConfig = config;
service.protect(wgGetSocketV4(currentTunnelHandle));
service.protect(wgGetSocketV6(currentTunnelHandle));
} else {
if (currentTunnelHandle == -1) {
Log.w(TAG, "Tunnel already down");
return;
}
wgTurnOff(currentTunnelHandle);
currentTunnel = null;
currentTunnelHandle = -1;
currentConfig = null;
}
tunnel.onStateChange(state);
}
/**
* Callback for {@link GoBackend} that is invoked when {@link VpnService} is started by the
* system's Always-On VPN mode.
*/
public interface AlwaysOnCallback {
void alwaysOnTriggered();
}
// TODO: When we finally drop API 21 and move to API 24, delete this and replace with the ordinary CompletableFuture.
private static final class GhettoCompletableFuture<V> {
private final LinkedBlockingQueue<V> completion = new LinkedBlockingQueue<>(1);
private final FutureTask<V> result = new FutureTask<>(completion::peek);
public boolean complete(final V value) {
final boolean offered = completion.offer(value);
if (offered)
result.run();
return offered;
}
public V get() throws ExecutionException, InterruptedException {
return result.get();
}
public V get(final long timeout, final TimeUnit unit) throws ExecutionException, InterruptedException, TimeoutException {
return result.get(timeout, unit);
}
public boolean isDone() {
return !completion.isEmpty();
}
public GhettoCompletableFuture<V> newIncompleteFuture() {
return new GhettoCompletableFuture<>();
}
}
/**
* {@link android.net.VpnService} implementation for {@link GoBackend}
*/
public static class VpnService extends android.net.VpnService {
@Nullable private GoBackend owner;
public Builder getBuilder() {
return new Builder();
}
@Override
public void onCreate() {
vpnService.complete(this);
super.onCreate();
}
@Override
public void onDestroy() {
if (owner != null) {
final Tunnel tunnel = owner.currentTunnel;
if (tunnel != null) {
if (owner.currentTunnelHandle != -1)
wgTurnOff(owner.currentTunnelHandle);
owner.currentTunnel = null;
owner.currentTunnelHandle = -1;
owner.currentConfig = null;
tunnel.onStateChange(State.DOWN);
}
}
vpnService = vpnService.newIncompleteFuture();
super.onDestroy();
}
@Override
public int onStartCommand(@Nullable final Intent intent, final int flags, final int startId) {
vpnService.complete(this);
if (intent == null || intent.getComponent() == null || !intent.getComponent().getPackageName().equals(getPackageName())) {
Log.d(TAG, "Service started by Always-on VPN feature");
if (alwaysOnCallback != null)
alwaysOnCallback.alwaysOnTriggered();
}
return super.onStartCommand(intent, flags, startId);
}
public void setOwner(final GoBackend owner) {
this.owner = owner;
}
}
}