GoBackend: integrate into app

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

app/src/main/java/com/wireguard/android/backend/GoBackend.java

@@ -0,0 +1,125 @@
+package com.wireguard.android.backend;
+
+import android.content.Context;
+import android.support.v4.util.ArraySet;
+import android.util.Log;
+
+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.Interface;
+import com.wireguard.config.Peer;
+import com.wireguard.crypto.KeyEncoding;
+
+import java.util.Collections;
+import java.util.Formatter;
+import java.util.Set;
+
+public final class GoBackend implements Backend {
+    private static final String TAG = "WireGuard/" + GoBackend.class.getSimpleName();
+
+    static {
+        System.loadLibrary("wg-go");
+    }
+
+    private final Context context;
+    private Tunnel currentTunnel;
+
+    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) {
+            // Do something (context.startService()...).
+            currentTunnel = tunnel;
+
+            Formatter fmt = new Formatter(new StringBuilder());
+            final Interface iface = config.getInterface();
+            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() != null)
+                fmt.format("listen_port=%d\n", Integer.parseInt(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.getEndpoint());
+                if (peer.getPersistentKeepalive() != null)
+                    fmt.format("persistent_keepalive_interval=%d\n", Integer.parseInt(peer.getPersistentKeepalive()));
+                if (peer.getAllowedIPs() != null) {
+                    for (final String allowedIp : peer.getAllowedIPs().split(" *, *")) {
+                        fmt.format("allowed_ip=%s\n", allowedIp);
+                    }
+                }
+            }
+            wgTurnOn(tunnel.getName(), -1, fmt.toString());
+        } else {
+            // Do something else.
+            currentTunnel = null;
+        }
+    }
+}

app/src/main/java/com/wireguard/android/backend/WgQuickBackend.java

@@ -88,8 +88,6 @@ public final class WgQuickBackend implements Backend {
             state = originalState == State.UP ? State.DOWN : State.UP;
         if (state == originalState)
             return originalState;
-        if (state == State.UP && !new File("/sys/module/wireguard").exists())
-            throw new ModuleNotLoadedException("WireGuard module not loaded");
         Log.d(TAG, "Changing tunnel " + tunnel.getName() + " to state " + state);
         toolsInstaller.ensureToolsAvailable();
         setStateInternal(tunnel, tunnel.getConfig(), state);
@@ -113,14 +111,4 @@ public final class WgQuickBackend implements Backend {
         if (result != 0)
             throw new Exception("Unable to configure tunnel (wg-quick returned " + result + ')');
     }
-
-    public static class ModuleNotLoadedException extends Exception {
-        public ModuleNotLoadedException(final String message, final Throwable cause) {
-            super(message, cause);
-        }
-
-        public ModuleNotLoadedException(final String message) {
-            super(message);
-        }
-    }
 }