feat(vpn): add destination-based VPN routing policy and standardize socket proxy forwarding

ts/vpn/classes.vpn-manager.ts

@@ -14,8 +14,6 @@ export interface IVpnManagerConfig {
   dns?: string[];
   /** Server endpoint hostname for client configs (e.g. 'vpn.example.com') */
   serverEndpoint?: string;
-  /** Override forwarding mode. Default: auto-detect (tun if root, socket otherwise) */
-  forwardingMode?: 'tun' | 'socket';
   /** Pre-defined VPN clients created on startup (idempotent — skips already-persisted clients) */
   initialClients?: Array<{
     clientId: string;
@@ -24,6 +22,13 @@ export interface IVpnManagerConfig {
   }>;
   /** Called when clients are created/deleted/toggled — triggers route re-application */
   onClientChanged?: () => void;
+  /** Destination routing policy override. Default: forceTarget to 127.0.0.1 */
+  destinationPolicy?: {
+    default: 'forceTarget' | 'block' | 'allow';
+    target?: string;
+    allowList?: string[];
+    blockList?: string[];
+  };
 }
 
 interface IPersistedServerKeys {
@@ -58,19 +63,10 @@ export class VpnManager {
   private vpnServer?: plugins.smartvpn.VpnServer;
   private clients: Map<string, IPersistedClient> = new Map();
   private serverKeys?: IPersistedServerKeys;
-  private _forwardingMode: 'tun' | 'socket';
 
   constructor(storageManager: StorageManager, config: IVpnManagerConfig) {
     this.storageManager = storageManager;
     this.config = config;
-    // Auto-detect forwarding mode: tun if root, socket otherwise
-    this._forwardingMode = config.forwardingMode
-      ?? (process.getuid?.() === 0 ? 'tun' : 'socket');
-  }
-
-  /** The effective forwarding mode (tun or socket). */
-  public get forwardingMode(): 'tun' | 'socket' {
-    return this._forwardingMode;
   }
 
   /** The VPN subnet CIDR. */
@@ -123,12 +119,14 @@ export class VpnManager {
       publicKey: this.serverKeys.noisePublicKey,
       subnet,
       dns: this.config.dns,
-      forwardingMode: this._forwardingMode,
+      forwardingMode: 'socket',
       transportMode: 'all',
       wgPrivateKey: this.serverKeys.wgPrivateKey,
       wgListenPort,
       clients: clientEntries,
-      socketForwardProxyProtocol: this._forwardingMode === 'socket',
+      socketForwardProxyProtocol: true,
+      destinationPolicy: this.config.destinationPolicy
+        ?? { default: 'forceTarget' as const, target: '127.0.0.1' },
     };
 
     await this.vpnServer.start(serverConfig);
@@ -147,7 +145,7 @@ export class VpnManager {
       }
     }
 
-    logger.log('info', `VPN server started: mode=${this._forwardingMode}, subnet=${subnet}, wg=:${wgListenPort}, clients=${this.clients.size}`);
+    logger.log('info', `VPN server started: subnet=${subnet}, wg=:${wgListenPort}, clients=${this.clients.size}`);
   }
 
   /**