Implement get and set tunnel config actions

Add three tunnel actions:
com.wireguard.android.action.GET_TUNNEL_CONFIG
com.wireguard.android.action.SET_TUNNEL_CONFIG
com.wireguard.android.action.SET_TUNNEL_USERSPACE_CONFIG

3 files changed, 34 insertions, 0 deletions

diff --git a/tunnel/src/main/java/com/wireguard/android/backend/Backend.java b/tunnel/src/main/java/com/wireguard/android/backend/Backend.java
index 4c18d98b..9afda719 100644
--- a/tunnel/src/main/java/com/wireguard/android/backend/Backend.java
+++ b/tunnel/src/main/java/com/wireguard/android/backend/Backend.java
@@ -19,6 +19,17 @@ import androidx.annotation.Nullable;
 @NonNullForAll
 public interface Backend {
     /**
+     * Update the volatile configuration of a running tunnel and return the resulting configuration.
+     * If the tunnel is not up, return the configuration that would result (if known), or else
+     * simply return the given configuration.
+     *
+     * @param tunnel The tunnel to apply the configuration to.
+     * @param config The new configuration for this tunnel.
+     * @return The updated configuration of the tunnel.
+     */
+    Config applyUserspaceConfig(ObservableTunnel tunnel, Config config) throws Exception;
+
+    /**
      * Enumerate names of currently-running tunnels.
      *
      * @return The set of running tunnel names.
diff --git a/tunnel/src/main/java/com/wireguard/android/backend/GoBackend.java b/tunnel/src/main/java/com/wireguard/android/backend/GoBackend.java
index 978b39aa..952a30f0 100644
--- a/tunnel/src/main/java/com/wireguard/android/backend/GoBackend.java
+++ b/tunnel/src/main/java/com/wireguard/android/backend/GoBackend.java
@@ -61,9 +61,26 @@ public final class GoBackend implements Backend {
 
     private static native int wgTurnOn(String ifName, int tunFd, String settings);
 
+    private static native String wgGetOperation(int handle);
+
+    private static native int wgSetOperation(int handle, String settings);
+
     private static native String wgVersion();
 
     @Override
+    public Config applyUserspaceConfig(final ObservableTunnel tunnel, final Config config) throws Exception {
+        if (currentTunnelHandle != -1) {
+            // Build config
+            final String goConfig = config.toWgUserspaceString();
+
+            Log.d(TAG, "Go backend v" + wgVersion());
+            wgSetOperation(currentTunnelHandle, goConfig);
+            Log.d(TAG, "Settings " + wgGetOperation(currentTunnelHandle));
+        }
+        return config;
+    }
+
+    @Override
     public Set<String> getRunningTunnelNames() {
         if (currentTunnel != null) {
             final Set<String> runningTunnels = new ArraySet<>();
@@ -216,6 +233,7 @@ public final class GoBackend implements Backend {
                     throw new BackendException(Reason.TUN_CREATION_ERROR);
                 Log.d(TAG, "Go backend v" + wgVersion());
                 currentTunnelHandle = wgTurnOn(tunnel.getName(), tun.detachFd(), goConfig);
+                Log.d(TAG, "Settings " + wgGetOperation(currentTunnelHandle));
             }
             if (currentTunnelHandle < 0)
                 throw new BackendException(Reason.GO_ACTIVATION_ERROR_CODE, currentTunnelHandle);
diff --git a/tunnel/src/main/java/com/wireguard/android/backend/WgQuickBackend.java b/tunnel/src/main/java/com/wireguard/android/backend/WgQuickBackend.java
index 78d7d5b6..c6a63691 100644
--- a/tunnel/src/main/java/com/wireguard/android/backend/WgQuickBackend.java
+++ b/tunnel/src/main/java/com/wireguard/android/backend/WgQuickBackend.java
@@ -55,6 +55,11 @@ public final class WgQuickBackend implements Backend {
     }
 
     @Override
+    public Config applyUserspaceConfig(final ObservableTunnel tunnel, final Config config) throws Exception {
+        throw new RuntimeException("Not implemented");
+    }
+
+    @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.