Shut down when no IPv4/6 routing available

Would fake-connect without VPN icon otherwise.

TunnelKit/Sources/AppExtension/TunnelKitProvider+Interaction.swift

@@ -129,6 +129,9 @@ extension TunnelKitProvider {
         /// An error occurred at the link level.
         case linkError
         
+        /// Network routing information is missing or incomplete.
+        case routing
+        
         /// The current network changed (e.g. switched from WiFi to data connection).
         case networkChanged
         

TunnelKit/Sources/AppExtension/TunnelKitProvider.swift

@@ -697,6 +697,9 @@ extension TunnelKitProvider {
             case .failedLinkWrite:
                 return .linkError
                 
+            case .noRouting:
+                return .routing
+
             default:
                 return .unexpectedReply
             }

TunnelKit/Sources/Core/SessionError.swift

@@ -76,6 +76,9 @@ public enum SessionError: String, Error {
 
     /// Server uses compression.
     case serverCompression
+
+    /// Missing routing information.
+    case noRouting
 }
 
 extension Error {

TunnelKit/Sources/Core/SessionProxy.swift

@@ -957,6 +957,11 @@ public class SessionProxy {
         }
         
         pushReply = reply
+        guard reply.options.ipv4 != nil || reply.options.ipv6 != nil else {
+            deferStop(.shutdown, SessionError.noRouting)
+            return
+        }
+        
         completeConnection()
 
         guard let remoteAddress = link?.remoteAddress else {