1 files changed, 292 insertions, 0 deletions
diff --git a/tunnel/src/main/java/com/wireguard/android/backend/GoBackend.java b/tunnel/src/main/java/com/wireguard/android/backend/GoBackend.java
new file mode 100644
index 00000000..6ad5afa4
--- /dev/null
+++ b/tunnel/src/main/java/com/wireguard/android/backend/GoBackend.java
@@ -0,0 +1,292 @@
+/*
+ * 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 androidx.annotation.Nullable;
+import androidx.collection.ArraySet;
+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 java.net.InetAddress;
+import java.util.Collections;
+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<>();
+    public interface AlwaysOnCallback {
+        void alwaysOnTriggered();
+    }
+    @Nullable private static AlwaysOnCallback alwaysOnCallback;
+    public static void setAlwaysOnCallback(AlwaysOnCallback cb) {
+        alwaysOnCallback = cb;
+    }
+
+    private final Context context;
+    @Nullable private Tunnel currentTunnel;
+    @Nullable private Config currentConfig;
+    private int currentTunnelHandle = -1;
+
+    public GoBackend(final Context context) {
+        SharedLibraryLoader.loadSharedLibrary(context, "wg-go");
+        this.context = context;
+    }
+
+    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();
+
+    @Override
+    public Set<String> getRunningTunnelNames() {
+        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) {
+        final Statistics stats = new Statistics();
+        if (tunnel != currentTunnel) {
+            return stats;
+        }
+        final String config = wgGetConfig(currentTunnelHandle);
+        Key key = null;
+        long rx = 0, 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;
+    }
+
+    @Override
+    public String getVersion() {
+        return wgVersion();
+    }
+
+    @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())
+                startVpnService();
+
+            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 InetNetwork addr : config.getInterface().getAddresses())
+                builder.addAddress(addr.getAddress(), addr.getMask());
+
+            for (final InetAddress addr : config.getInterface().getDnsServers())
+                builder.addDnsServer(addr.getHostAddress());
+
+            for (final Peer peer : config.getPeers()) {
+                for (final InetNetwork addr : peer.getAllowedIps())
+                    builder.addRoute(addr.getAddress(), addr.getMask());
+            }
+
+            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);
+    }
+
+    private void startVpnService() {
+        Log.d(TAG, "Requesting to start VpnService");
+        context.startService(new Intent(context, VpnService.class));
+    }
+
+    public static class VpnService extends android.net.VpnService {
+        @Nullable private GoBackend owner;
+
+        public void setOwner(final GoBackend owner) {
+            this.owner = 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);
+        }
+    }
+}