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/*
* Copyright © 2018 Samuel Holland <samuel@sholland.org>
* Copyright © 2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
* SPDX-License-Identifier: GPL-2.0-or-later
*/
package com.wireguard.android.backend;
import android.content.Context;
import android.content.Intent;
import android.os.ParcelFileDescriptor;
import android.support.v4.util.ArraySet;
import android.util.Log;
import com.wireguard.android.Application;
import com.wireguard.android.model.Tunnel;
import com.wireguard.android.model.Tunnel.State;
import com.wireguard.android.model.Tunnel.Statistics;
import com.wireguard.config.Config;
import com.wireguard.config.IPCidr;
import com.wireguard.config.Interface;
import com.wireguard.config.Peer;
import com.wireguard.crypto.KeyEncoding;
import java.net.InetAddress;
import java.util.Collections;
import java.util.Formatter;
import java.util.Set;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java9.util.concurrent.CompletableFuture;
public final class GoBackend implements Backend {
private static final String TAG = "WireGuard/" + GoBackend.class.getSimpleName();
private static CompletableFuture<VpnService> vpnService = new CompletableFuture<>();
static {
System.loadLibrary("wg-go");
}
private final Context context;
private Tunnel currentTunnel;
private int currentTunnelHandle = -1;
public GoBackend(final Context context) {
this.context = context;
}
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);
@Override
public Config applyConfig(final Tunnel tunnel, final Config config) throws Exception {
if (tunnel.getState() == State.UP) {
// Restart the tunnel to apply the new config.
setStateInternal(tunnel, tunnel.getConfig(), State.DOWN);
try {
setStateInternal(tunnel, config, State.UP);
} catch (final Exception e) {
// The new configuration didn't work, so try to go back to the old one.
setStateInternal(tunnel, tunnel.getConfig(), State.UP);
throw e;
}
}
return config;
}
@Override
public Set<String> enumerate() {
if (currentTunnel != null) {
final Set<String> runningTunnels = new ArraySet<>();
runningTunnels.add(currentTunnel.getName());
return runningTunnels;
}
return Collections.emptySet();
}
@Override
public State getState(final Tunnel tunnel) {
return currentTunnel == tunnel ? State.UP : State.DOWN;
}
@Override
public Statistics getStatistics(final Tunnel tunnel) {
return new Statistics();
}
@Override
public State setState(final Tunnel tunnel, State state) throws Exception {
final State originalState = getState(tunnel);
if (state == State.TOGGLE)
state = originalState == State.UP ? State.DOWN : State.UP;
if (state == originalState)
return originalState;
if (state == State.UP && currentTunnel != null)
throw new IllegalStateException("Only one userspace tunnel can run at a time");
Log.d(TAG, "Changing tunnel " + tunnel.getName() + " to state " + state);
setStateInternal(tunnel, tunnel.getConfig(), state);
return getState(tunnel);
}
private void setStateInternal(final Tunnel tunnel, final Config config, final State state)
throws Exception {
if (state == State.UP) {
Log.i(TAG, "Bringing tunnel up");
if (VpnService.prepare(context) != null)
throw new Exception("VPN service not authorized by user");
final VpnService service;
if (!vpnService.isDone())
startVpnService();
try {
service = vpnService.get(2, TimeUnit.SECONDS);
} catch (final TimeoutException e) {
throw new Exception("Unable to start Android VPN service", e);
}
if (currentTunnelHandle != -1) {
Log.w(TAG, "Tunnel already up");
return;
}
// Build config
final Interface iface = config.getInterface();
final String goConfig;
try (Formatter fmt = new Formatter(new StringBuilder())) {
fmt.format("replace_peers=true\n");
if (iface.getPrivateKey() != null)
fmt.format("private_key=%s\n", KeyEncoding.keyToHex(KeyEncoding.keyFromBase64(iface.getPrivateKey())));
if (iface.getListenPort() != 0)
fmt.format("listen_port=%d\n", config.getInterface().getListenPort());
for (final Peer peer : config.getPeers()) {
if (peer.getPublicKey() != null)
fmt.format("public_key=%s\n", KeyEncoding.keyToHex(KeyEncoding.keyFromBase64(peer.getPublicKey())));
if (peer.getPreSharedKey() != null)
fmt.format("preshared_key=%s\n", KeyEncoding.keyToHex(KeyEncoding.keyFromBase64(peer.getPreSharedKey())));
if (peer.getEndpoint() != null)
fmt.format("endpoint=%s\n", peer.getResolvedEndpointString());
if (peer.getPersistentKeepalive() != 0)
fmt.format("persistent_keepalive_interval=%d\n", peer.getPersistentKeepalive());
for (final IPCidr addr : peer.getAllowedIPs()) {
fmt.format("allowed_ip=%s\n", addr.toString());
}
}
goConfig = fmt.toString();
}
// Create the vpn tunnel with android API
final VpnService.Builder builder = service.getBuilder();
builder.setSession(tunnel.getName());
for (final IPCidr addr : config.getInterface().getAddresses())
builder.addAddress(addr.getAddress(), addr.getCidr());
for (final InetAddress addr : config.getInterface().getDnses())
builder.addDnsServer(addr.getHostAddress());
for (final Peer peer : config.getPeers()) {
for (final IPCidr addr : peer.getAllowedIPs())
builder.addRoute(addr.getAddress(), addr.getCidr());
}
int mtu = config.getInterface().getMtu();
if (mtu == 0)
mtu = 1280;
builder.setMtu(mtu);
builder.setBlocking(true);
final ParcelFileDescriptor tun = builder.establish();
if (tun == null)
throw new Exception("Unable to create tun device");
currentTunnelHandle = wgTurnOn(tunnel.getName(), tun.detachFd(), goConfig);
if (currentTunnelHandle < 0)
throw new Exception("Unable to turn tunnel on (wgTurnOn return " + currentTunnelHandle + ')');
currentTunnel = tunnel;
service.protect(wgGetSocketV4(currentTunnelHandle));
service.protect(wgGetSocketV6(currentTunnelHandle));
} else {
Log.i(TAG, "Bringing tunnel down");
if (currentTunnelHandle == -1) {
Log.w(TAG, "Tunnel already down");
return;
}
wgTurnOff(currentTunnelHandle);
currentTunnel = null;
currentTunnelHandle = -1;
}
}
private void startVpnService() {
context.startService(new Intent(context, VpnService.class));
}
public static class VpnService extends android.net.VpnService {
public Builder getBuilder() {
return new Builder();
}
@Override
public void onCreate() {
vpnService.complete(this);
super.onCreate();
}
@Override
public void onDestroy() {
for (final Tunnel tunnel : Application.getComponent().getTunnelManager().getTunnels()) {
if (tunnel != null && tunnel.getState() != State.DOWN)
tunnel.setState(State.DOWN);
}
vpnService = vpnService.newIncompleteFuture();
super.onDestroy();
}
}
}
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