replace ErrorCode with error description

client/src/cordova/apple/OutlineAppleLib/Sources/OutlineTunnel/OutlineVpn.swift

@@ -50,7 +50,7 @@ public class OutlineVpn: NSObject {
   // MARK: Interface
 
   /** Starts a VPN tunnel as specified in the OutlineTunnel object. */
-  public func start(_ tunnelId: String, name: String?, transportConfig: [String: Any]) async -> ErrorCode {
+  public func start(_ tunnelId: String, name: String?, transportConfig: [String: Any]) async -> String? {
     if let manager = await getTunnelManager(), isActiveSession(manager.connection) {
       DDLogDebug("Stoppping active session before starting new one")
       await stopSession(manager)
@@ -61,7 +61,7 @@ public class OutlineVpn: NSObject {
       manager = try await setupVpn(withId: tunnelId, named: name ?? "Outline Server", withTransport: transportConfig)
     } catch {
       DDLogError("Failed to setup VPN: \(error.localizedDescription))")
-      return ErrorCode.vpnPermissionNotGranted;
+      return "VPN permission is not granted";
     }
     let session = manager.connection as! NETunnelProviderSession
 
@@ -98,7 +98,7 @@ public class OutlineVpn: NSObject {
       DDLogDebug("NETunnelProviderSession.startTunnel() returned")
     } catch let error as NSError  {
       DDLogError("Failed to start VPN: \(error.localizedDescription)")
-      return ErrorCode.vpnStartFailure
+      return error.localizedDescription
     }
 
     // Wait for it to be done.
@@ -108,14 +108,13 @@ public class OutlineVpn: NSObject {
     case .connected:
       break
     case .disconnected:
-      return ErrorCode.vpnStartFailure
+      return "Failed to start VPN"
     case .invalid:
-      return ErrorCode.systemMisconfigured
+      return "VPN profile has been modified"
     default:
       // This shouldn't happen.
-      return ErrorCode.systemMisconfigured
+      return "Unknown connection status"
     }
-    //
 
     // Set an on-demand rule to connect to any available network to implement auto-connect on boot
     do { try await manager.loadFromPreferences() }
@@ -129,22 +128,22 @@ public class OutlineVpn: NSObject {
     catch {
       DDLogWarn("OutlineVpn.start: Failed to save on-demand preference change: \(error.localizedDescription)")
     }
-    return ErrorCode.noError
+    return nil
   }
 
   /** Starts the last successful VPN tunnel. */
   @objc public func startLastSuccessfulTunnel(_ completion: @escaping (Callback)) {
     Task {
       guard let manager = await getTunnelManager() else {
         DDLogDebug("Tunnel manager not setup")
-        completion(ErrorCode.illegalServerConfiguration)
+        completion("Failed to get TunnelManager")
         return
       }
       do {
         try manager.connection.startVPNTunnel()
-        completion(ErrorCode.noError)
+        completion(nil)
       } catch {
-        completion(ErrorCode.vpnStartFailure)
+        completion("Failed to start VPN")
       }
     }
   }
@@ -227,7 +226,7 @@ public class OutlineVpn: NSObject {
     }
     guard let manager = session.manager as? NETunnelProviderManager else {
       // For some reason we get spurious notifications with connecting and disconnecting states
-      DDLogDebug("Bad manager in OutlineVpn.vpnStatusChanged session=\(String(describing:session)) status=\(String(describing: session.status)) manager=\(session.manager)")
+      DDLogDebug("Bad manager in OutlineVpn.vpnStatusChanged session=\(String(describing:session))")
       return
     }
     guard let protoConfig = manager.protocolConfiguration as? NETunnelProviderProtocol,

client/src/cordova/apple/OutlineLib/VpnExtension/Sources/PacketTunnelProvider.m

@@ -32,9 +32,8 @@ @interface PacketTunnelProvider ()<Tun2socksTunWriter>
 @property (nonatomic) NSString *hostNetworkAddress;  // IP address of the host in the active network.
 @property id<Tun2socksTunnel> tunnel;
 
-// result callbacks for 'start' and 'stop', accepts a nullable error string
-@property (nonatomic, copy) void (^startCompletion)(NSString * _Nullable);
-@property (nonatomic, copy) void (^stopCompletion)(NSString * _Nullable);
+// mimics fetchLastDisconnectErrorWithCompletionHandler on older systems
+@property (nullable) NSError *lastDisconnectError;
 
 @property (nonatomic) DDFileLogger *fileLogger;
 @property (nonatomic, nullable) OutlineTunnel *transportConfig;
@@ -62,10 +61,16 @@ - (id)init {
 }
 
 - (void)startTunnelWithOptions:(NSDictionary *)options
-             completionHandler:(void (^)(NSError *))startDone {
+             completionHandler:(void (^)(NSError *))completion {
   DDLogInfo(@"Starting tunnel");
   DDLogDebug(@"Options are %@", options);
 
+  // mimics fetchLastDisconnectErrorWithCompletionHandler on older systems
+  void (^startDone)(NSError *) = ^(NSError *err) {
+    self.lastDisconnectError = err;
+    completion(err);
+  };
+
   // MARK: Process Config.
   if (self.protocolConfiguration == nil) {
     DDLogError(@"Failed to retrieve NETunnelProviderProtocol.");
@@ -121,31 +126,34 @@ - (void)startTunnelWithOptions:(NSDictionary *)options
     NSError *err = nil;
     ShadowsocksClient* client = [self newClientWithError:&err];
     if (err != nil) {
-      return startDone(err);
+      return startDone([NSError errorWithDomain:NEVPNErrorDomain
+                                           code:NEVPNErrorConfigurationReadWriteFailed
+                                       userInfo:nil]);
     }
 
     long connStatus;
     ShadowsocksCheckConnectivity(client, &connStatus, &err);
     if (err != nil) {
-      return completionHandler(err);
+      return startDone(err);
     }
     supportUDP = ((connStatus & ShadowsocksUDPConnected) == ShadowsocksUDPConnected);
   }
 
   [self startRouting:[OutlineTunnel getTunnelNetworkSettings]
-           completion:^(NSError *_Nullable error) {
-             if (error != nil) {
-               return startDone(error);
-             }
-             BOOL isUdpSupported = isOnDemand ? self.isUdpSupported : supportUDP;
-             if (![self startTun2Socks:isUdpSupported]) {
-               return startDone([NSError errorWithDomain:NEVPNErrorDomain
-                                                            code:NEVPNErrorConnectionFailed
-                                                        userInfo:nil]);
-             }
-             [self listenForNetworkChanges];
-             startDone(nil);
-           }];
+          completion:^(NSError *_Nullable error) {
+            if (error != nil) {
+              return startDone(error);
+            }
+            BOOL isUdpSupported = isOnDemand ? self.isUdpSupported : supportUDP;
+            [self startTun2SocksWithUDPSupported:isUdpSupported error:&error];
+            if (error != nil) {
+              return startDone([NSError errorWithDomain:NEVPNErrorDomain
+                                                   code:NEVPNErrorConnectionFailed
+                                               userInfo:nil]);
+            }
+            [self listenForNetworkChanges];
+            startDone(nil);
+          }];
 }
 
 - (void)stopTunnelWithReason:(NEProviderStopReason)reason
@@ -181,7 +189,7 @@ - (void)startRouting:(NEPacketTunnelNetworkSettings *)settings
   __weak PacketTunnelProvider *weakSelf = self;
   [self setTunnelNetworkSettings:settings completionHandler:^(NSError * _Nullable error) {
     if (error != nil) {
-      DDLogError(@"Failed to start routing: %@", error.localizedDescription);
+      DDLogError(@"Failed to start routing: %@", error);
     } else {
       DDLogInfo(@"Routing started");
       // Passing nil settings clears the tunnel network configuration. Indicate to the system that