## Summary
Server-side movement throttle that prevents speed hacking while accurately identifying cheaters with detection of lagging connections.
**Key features:**
- Credit buffer (200ms) absorbs timing jitter from legitimate players
- Movement queue handles larger bursts, draining at proper game-tick intervals
- RTT measurement distinguishes network lag from speed hacks
- Queue depth detection catches ACK-throttled speed hacks (going straight)
## How It Works
**Throttle** (prevention): Movements arriving too early either consume credit or get queued. The queue drains at
correct intervals, so speed hackers can't move faster regardless of what they send.
**Detection** (identification): Combines multiple signals to identify cheaters:
| Signal | What it catches |
|--------|-----------------|
| Queue depth ≥4 sustained | ACK-throttled speed hacks (client limits unacked moves to 5) |
| Movement rate >1.05x | Direction-change speed hacks where timing is visible |
| Stable RTT + high queue | Eliminates false positives from laggy players |
**RTT-Aware Logic:**
- Probes only sent to players actively moving (event-driven, not global loop)
- Stable low-latency + problems = suspicious
- Unstable/high-latency + problems = probably just lag, throttle handles it
## Configuration
```json
{
"movementThrottle.maxCredit": 200,
"movementThrottle.softQueueLimit": 6,
"movementThrottle.hardQueueLimit": 10,
"movementThrottle.debugLogging": false
}
```
94 lines
3.5 KiB
C#
94 lines
3.5 KiB
C#
using Server.Commands;
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using Server.Network;
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using Server.Targeting;
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namespace Server.Commands;
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public static class MovementDebugCommands
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{
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public static void Configure()
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{
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CommandSystem.Register("MovementDebug", AccessLevel.GameMaster, MovementDebug_OnCommand);
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CommandSystem.Register("MovementStats", AccessLevel.GameMaster, MovementStats_OnCommand);
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// Subscribe to speed hack detection events and broadcast to online staff
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MovementThrottle.OnSpeedHackDetected += OnSpeedHackDetected;
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}
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private static void OnSpeedHackDetected(
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NetState ns,
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Mobile mobile,
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float rate,
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MovementThrottle.DetectionVerdict verdict,
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string urgency)
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{
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if (mobile == null)
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{
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return;
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}
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var hue = urgency switch
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{
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"HIGH" => 0x25, // Red
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"MEDIUM" => 0x35, // Orange
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_ => 0x3B // Yellow
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};
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CommandHandlers.BroadcastMessage(
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AccessLevel.Counselor,
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hue,
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$"[{urgency}] Speed hack: {mobile.RawName} ({ns.Account?.Username}) " +
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$"Rate:{rate:F2} Verdict:{verdict} @ {mobile.Location} {mobile.Map?.Name}"
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);
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}
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[Usage("MovementDebug")]
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[Description("Target a player to toggle verbose movement logging for their connection.")]
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private static void MovementDebug_OnCommand(CommandEventArgs e)
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{
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e.Mobile.BeginTarget(-1, false, TargetFlags.None, MovementDebug_OnTarget);
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e.Mobile.SendMessage("Target a player to toggle movement debug logging.");
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}
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private static void MovementDebug_OnTarget(Mobile from, object obj)
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{
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if (obj is not Mobile target || target.NetState == null)
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{
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from.SendMessage("That is not a valid online player.");
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return;
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}
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var ns = target.NetState;
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ns.MovementLogging = !ns.MovementLogging;
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var state = ns.MovementLogging ? "ENABLED" : "DISABLED";
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from.SendMessage($"Movement debug logging {state} for {target.RawName}.");
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}
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[Usage("MovementStats")]
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[Description("Target a player to see their current movement throttle state.")]
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private static void MovementStats_OnCommand(CommandEventArgs e)
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{
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e.Mobile.BeginTarget(-1, false, TargetFlags.None, MovementStats_OnTarget);
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e.Mobile.SendMessage("Target a player to view their movement stats.");
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}
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private static void MovementStats_OnTarget(Mobile from, object obj)
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{
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if (obj is not Mobile target || target.NetState == null)
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{
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from.SendMessage("That is not a valid online player.");
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return;
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}
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var stats = MovementThrottle.GetMovementStats(target.NetState);
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from.SendMessage($"--- Movement Stats for {target.RawName} ---");
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from.SendMessage($"Rate: {stats.Rate:F3} ({stats.SampleCount} samples) | Verdict: {stats.Verdict} | Confidence: {stats.Confidence:P0}");
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from.SendMessage($"RTT: avg={stats.AverageRtt}ms last={stats.LastRtt}ms var={stats.RttVariance} stable={stats.StableConnection} samples={stats.RttSampleCount}");
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from.SendMessage($"Queue: depth={stats.QueueDepth} | Credit: {stats.MovementCredit}ms");
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from.SendMessage($"Packet rate: {stats.CurrentPacketRate}/s (peak: {stats.PeakPacketRate}/s)");
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from.SendMessage($"Burst: size={stats.BurstSize} gap={stats.PrecedingGap}ms | Sustained: {stats.SustainedSeconds}s");
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from.SendMessage($"Debug logging: {(stats.DebugLogging ? "ON" : "OFF")}");
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}
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}
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