1 files changed, 61 insertions, 0 deletions
diff --git a/tunnel/src/main/java/com/wireguard/android/backend/BackendException.java b/tunnel/src/main/java/com/wireguard/android/backend/BackendException.java
new file mode 100644
index 00000000..94f7b098
--- /dev/null
+++ b/tunnel/src/main/java/com/wireguard/android/backend/BackendException.java
@@ -0,0 +1,61 @@
+/*
+ * Copyright © 2017-2025 WireGuard LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package com.wireguard.android.backend;
+
+import com.wireguard.util.NonNullForAll;
+
+/**
+ * A subclass of {@link Exception} that encapsulates the reasons for a failure originating in
+ * implementations of {@link Backend}.
+ */
+@NonNullForAll
+public final class BackendException extends Exception {
+    private final Object[] format;
+    private final Reason reason;
+
+    /**
+     * Public constructor for BackendException.
+     *
+     * @param reason The {@link Reason} which caused this exception to be thrown
+     * @param format Format string values used when converting exceptions to user-facing strings.
+     */
+    public BackendException(final Reason reason, final Object... format) {
+        this.reason = reason;
+        this.format = format;
+    }
+
+    /**
+     * Get the format string values associated with the instance.
+     *
+     * @return Array of {@link Object} for string formatting purposes
+     */
+    public Object[] getFormat() {
+        return format;
+    }
+
+    /**
+     * Get the reason for this exception.
+     *
+     * @return Associated {@link Reason} for this exception.
+     */
+    public Reason getReason() {
+        return reason;
+    }
+
+    /**
+     * Enum class containing all known reasons for why a {@link BackendException} might be thrown.
+     */
+    public enum Reason {
+        UNKNOWN_KERNEL_MODULE_NAME,
+        WG_QUICK_CONFIG_ERROR_CODE,
+        TUNNEL_MISSING_CONFIG,
+        VPN_NOT_AUTHORIZED,
+        UNABLE_TO_START_VPN,
+        TUN_CREATION_ERROR,
+        GO_ACTIVATION_ERROR_CODE,
+        DNS_RESOLUTION_FAILURE,
+    }
+}