Remove secondary AllowPortForward setting.

The global setting is fine, and this simplifies
both the code and the UI.

OpenRA.Game/Game.cs

@@ -327,13 +327,8 @@ namespace OpenRA
 
 			GeoIP.Initialize();
 
-			if (!Settings.Server.DiscoverNatDevices)
-				Settings.Server.AllowPortForward = false;
-			else
-			{
+			if (Settings.Server.DiscoverNatDevices)
 				discoverNat = UPnP.DiscoverNatDevices(Settings.Server.NatDiscoveryTimeout);
-				Settings.Server.AllowPortForward = true;
-			}
 
 			var modSearchArg = args.GetValue("Engine.ModSearchPaths", null);
 			var modSearchPaths = modSearchArg != null ?
@@ -461,7 +456,6 @@ namespace OpenRA
 			{
 				Console.WriteLine("NAT discovery failed: {0}", e.Message);
 				Log.Write("nat", e.ToString());
-				Settings.Server.AllowPortForward = false;
 			}
 
 			ModData.LoadScreen.StartGame(args);
@@ -871,8 +865,7 @@ namespace OpenRA
 			{
 				Name = "Skirmish Game",
 				Map = map,
-				AdvertiseOnline = false,
-				AllowPortForward = false
+				AdvertiseOnline = false
 			};
 
 			server = new Server.Server(new IPEndPoint(IPAddress.Loopback, 0), settings, ModData, false);

OpenRA.Game/Network/UPnP.cs

@@ -20,15 +20,22 @@ using Open.Nat;
 
 namespace OpenRA.Network
 {
+	public enum UPnPStatus { Enabled, Disabled, NotSupported }
+
 	public class UPnP
 	{
 		static NatDevice natDevice;
 		static Mapping mapping;
+		static bool initialized;
 
 		public static IPAddress ExternalIP { get; private set; }
+		public static UPnPStatus Status { get { return initialized ? natDevice != null ?
+			UPnPStatus.Enabled : UPnPStatus.NotSupported : UPnPStatus.Disabled; } }
 
 		public static async Task DiscoverNatDevices(int timeout)
 		{
+			initialized = true;
+
 			NatDiscoverer.TraceSource.Switch.Level = SourceLevels.Verbose;
 			var logChannel = Log.Channel("nat");
 			NatDiscoverer.TraceSource.Listeners.Add(new TextWriterTraceListener(logChannel.Writer));

OpenRA.Game/Server/Server.cs

@@ -134,8 +134,7 @@ namespace OpenRA.Server
 
 			randomSeed = (int)DateTime.Now.ToBinary();
 
-			// UPnP is only supported for servers created by the game client.
-			if (!dedicated && Settings.AllowPortForward)
+			if (UPnP.Status == UPnPStatus.Enabled)
 				UPnP.ForwardPort(Settings.ListenPort, Settings.ExternalPort).Wait();
 
 			foreach (var trait in modData.Manifest.ServerTraits)
@@ -206,7 +205,7 @@ namespace OpenRA.Server
 					if (State == ServerState.ShuttingDown)
 					{
 						EndGame();
-						if (!dedicated && Settings.AllowPortForward)
+						if (UPnP.Status == UPnPStatus.Enabled)
 							UPnP.RemovePortForward().Wait();
 						break;
 					}

OpenRA.Game/Settings.cs

@@ -54,9 +54,6 @@ namespace OpenRA
 		[Desc("Allow users to enable NAT discovery for external IP detection and automatic port forwarding.")]
 		public bool DiscoverNatDevices = false;
 
-		[Desc("Set this to false to disable UPnP even if compatible devices are found.")]
-		public bool AllowPortForward = true;
-
 		[Desc("Time in milliseconds to search for UPnP enabled NAT devices.")]
 		public int NatDiscoveryTimeout = 1000;