add commands: `ban stage <stage-name>` and `unban stage <stage-name>`

To kick players from the server when they enter a banned stage.

<stage-name> can also be a kingdom alias, which bans/unbans all stages in that kingdom.

Because we aren't banning the player, d/c them would be no good, because of the client auto reconnect.
Instead send them the crash and ignore all packets by them until they d/c on their own.

This is an alternative solution for issue #43.

Server/BanLists.cs

@@ -2,6 +2,7 @@ using System.Net;
 using System.Net.Sockets;
 using System.Text;
 
+using Shared;
 using Shared.Packet.Packets;
 
 namespace Server;
@@ -30,6 +31,12 @@ public static class BanLists {
         }
     }
 
+    private static ISet<string> Stages {
+        get {
+            return Settings.Instance.BanList.Stages;
+        }
+    }
+
 
     private static bool IsIPv4(string str) {
         return IPAddress.TryParse(str, out IPAddress? ip)
@@ -62,6 +69,10 @@ public static class BanLists {
         return Profiles.Contains(id);
     }
 
+    public static bool IsStageBanned(string stage) {
+        return Stages.Contains(stage);
+    }
+
     public static bool IsClientBanned(Client user) {
         return IsProfileBanned(user) || IsIPv4Banned(user);
     }
@@ -91,6 +102,10 @@ public static class BanLists {
         Profiles.Add(id);
     }
 
+    private static void BanStage(string stage) {
+        Stages.Add(stage);
+    }
+
     private static void BanClient(Client user) {
         BanProfile(user);
         BanIPv4(user);
@@ -121,22 +136,36 @@ public static class BanLists {
         Profiles.Remove(id);
     }
 
+    private static void UnbanStage(string stage) {
+        Stages.Remove(stage);
+    }
+
 
     private static void Save() {
         Settings.SaveSettings(true);
     }
 
 
-    public static void Crash(Client user, bool permanent = false) {
+    public static void Crash(
+        Client user,
+        bool permanent    = false,
+        bool dispose_user = true,
+        int  delay_ms     = 0
+    ) {
         user.Ignored = true;
         Task.Run(async () => {
+            if (delay_ms > 0) {
+                await Task.Delay(delay_ms);
+            }
             await user.Send(new ChangeStagePacket {
                 Id              = (permanent ? "$agogus/ban4lyfe" : "$among$us/cr4sh%"),
                 Stage           = (permanent ? "$ejected"         : "$agogusStage"),
                 Scenario        = (sbyte) (permanent ? 69 : 21),
                 SubScenarioType = (byte)  (permanent ? 21 : 69),
             });
-            user.Dispose();
+            if (dispose_user) {
+                user.Dispose();
+            }
         });
     }
 
@@ -149,7 +178,7 @@ public static class BanLists {
 
     public static string HandleBanCommand(string[] args, MUCH much) {
         if (args.Length == 0) {
-            return "Usage: ban {list|enable|disable|player|profile|ip} ...";
+            return "Usage: ban {list|enable|disable|player|profile|ip|stage} ...";
         }
 
         string cmd = args[0];
@@ -157,7 +186,7 @@ public static class BanLists {
 
         switch (cmd) {
             default:
-                return "Usage: ban {list|enable|disable|player|profile|ip} ...";
+                return "Usage: ban {list|enable|disable|player|profile|ip|stage} ...";
 
             case "list":
                 if (args.Length != 0) {
@@ -176,6 +205,11 @@ public static class BanLists {
                     list.Append(string.Join("\n- ", Profiles));
                 }
 
+                if (Stages.Count > 0) {
+                    list.Append("\nBanned stages:\n- ");
+                    list.Append(string.Join("\n- ", Stages));
+                }
+
                 return list.ToString();
 
             case "enable":
@@ -247,13 +281,35 @@ public static class BanLists {
                 CrashMultiple(args, much);
                 Save();
                 return "Banned ip: " + args[0];
+
+            case "stage":
+                if (args.Length != 1) {
+                    return "Usage: ban stage <stage-name>";
+                }
+                string? stage = Shared.Stages.Input2Stage(args[0]);
+                if (stage == null) {
+                    return "Invalid stage name!";
+                }
+                if (IsStageBanned(stage)) {
+                    return "Stage " + stage + " is already banned.";
+                }
+                var stages = Shared.Stages
+                    .StagesByInput(args[0])
+                    .Where(s => !IsStageBanned(s))
+                    .ToList()
+                ;
+                foreach (string s in stages) {
+                    BanStage(s);
+                }
+                Save();
+                return "Banned stage: " + string.Join(", ", stages);
         }
     }
 
 
     public static string HandleUnbanCommand(string[] args) {
         if (args.Length != 2) {
-            return "Usage: unban {profile|ip} <value>";
+            return "Usage: unban {profile|ip|stage} <value>";
         }
 
         string cmd = args[0];
@@ -261,7 +317,7 @@ public static class BanLists {
 
         switch (cmd) {
             default:
-                return "Usage: unban {profile|ip} <value>";
+                return "Usage: unban {profile|ip|stage} <value>";
 
             case "profile":
                 if (!Guid.TryParse(val, out Guid id)) {
@@ -284,6 +340,22 @@ public static class BanLists {
                 UnbanIPv4(val);
                 Save();
                 return "Unbanned ip: " + val;
+
+            case "stage":
+                string stage = Shared.Stages.Input2Stage(val) ?? val;
+                if (!IsStageBanned(stage)) {
+                    return "Stage " + stage + " is not banned.";
+                }
+                var stages = Shared.Stages
+                    .StagesByInput(val)
+                    .Where(IsStageBanned)
+                    .ToList()
+                ;
+                foreach (string s in stages) {
+                    UnbanStage(s);
+                }
+                Save();
+                return "Unbanned stage: " + string.Join(", ", stages);
         }
     }
 }

Server/Program.cs

@@ -113,6 +113,11 @@ float MarioSize(bool is2d) => is2d ? 180 : 160;
 server.PacketHandler = (c, p) => {
     switch (p) {
         case GamePacket gamePacket: {
+            if (BanLists.Enabled && BanLists.IsStageBanned(gamePacket.Stage)) {
+                c.Logger.Warn($"Crashing player for entering banned stage {gamePacket.Stage}.");
+                BanLists.Crash(c, false, false, 500);
+                return false;
+            }
             c.Logger.Info($"Got game packet {gamePacket.Stage}->{gamePacket.ScenarioNum}");
             c.Metadata["scenario"] = gamePacket.ScenarioNum;
             c.Metadata["2d"] = gamePacket.Is2d;

Server/Settings.cs

@@ -62,6 +62,7 @@ public class Settings {
         public bool Enabled { get; set; } = false;
         public ISet<Guid> Players { get; set; } = new SortedSet<Guid>();
         public ISet<string> IpAddresses { get; set; } = new SortedSet<string>();
+        public ISet<string> Stages { get; set; } = new SortedSet<string>();
     }
 
     public class FlipTable {

Shared/Stages.cs

@@ -11,7 +11,7 @@ public static class Stages {
             return mapName;
         }
         // exact stage value
-        if (Stage2Alias.ContainsKey(input)) {
+        if (IsStage(input)) {
             return input;
         }
         // force input value with a !
@@ -29,6 +29,32 @@ public static class Stages {
         return result;
     }
 
+    public static bool IsAlias(string input) {
+        return Alias2Stage.ContainsKey(input);
+    }
+
+    public static bool IsStage(string input) {
+        return Stage2Alias.ContainsKey(input);
+    }
+
+    public static IEnumerable<string> StagesByInput(string input) {
+        if (IsAlias(input)) {
+            var stages = Stage2Alias
+                .Where(e => e.Value == input)
+                .Select(e => e.Key)
+            ;
+            foreach (string stage in stages) {
+                yield return stage;
+            }
+        }
+        else {
+            string? stage = Input2Stage(input);
+            if (stage != null) {
+                yield return stage;
+            }
+        }
+    }
+
     public static readonly Dictionary<string, string> Alias2Stage = new Dictionary<string, string>() {
         { "cap",     "CapWorldHomeStage"       },
         { "cascade", "WaterfallWorldHomeStage" },