1 files changed, 57 insertions, 0 deletions
diff --git a/tunnel/src/main/java/com/wireguard/android/backend/Tunnel.java b/tunnel/src/main/java/com/wireguard/android/backend/Tunnel.java
new file mode 100644
index 00000000..dbc91c27
--- /dev/null
+++ b/tunnel/src/main/java/com/wireguard/android/backend/Tunnel.java
@@ -0,0 +1,57 @@
+/*
+ * Copyright © 2017-2025 WireGuard LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package com.wireguard.android.backend;
+
+import com.wireguard.util.NonNullForAll;
+
+import java.util.regex.Pattern;
+
+/**
+ * Represents a WireGuard tunnel.
+ */
+
+@NonNullForAll
+public interface Tunnel {
+    int NAME_MAX_LENGTH = 15;
+    Pattern NAME_PATTERN = Pattern.compile("[a-zA-Z0-9_=+.-]{1,15}");
+
+    static boolean isNameInvalid(final CharSequence name) {
+        return !NAME_PATTERN.matcher(name).matches();
+    }
+
+    /**
+     * Get the name of the tunnel, which should always pass the !isNameInvalid test.
+     *
+     * @return The name of the tunnel.
+     */
+    String getName();
+
+    /**
+     * React to a change in state of the tunnel. Should only be directly called by Backend.
+     *
+     * @param newState The new state of the tunnel.
+     */
+    void onStateChange(State newState);
+
+    /**
+     * Enum class to represent all possible states of a {@link Tunnel}.
+     */
+    enum State {
+        DOWN,
+        TOGGLE,
+        UP;
+
+        /**
+         * Get the state of a {@link Tunnel}
+         *
+         * @param running boolean indicating if the tunnel is running.
+         * @return State of the tunnel based on whether or not it is running.
+         */
+        public static State of(final boolean running) {
+            return running ? UP : DOWN;
+        }
+    }
+}