Prevent infinite loops in device linking (#16856)

Content.Shared/DeviceLinking/DeviceLinkSinkComponent.cs

@@ -19,4 +19,20 @@ public sealed class DeviceLinkSinkComponent : Component
     /// </summary>
     [DataField("links")]
     public HashSet<EntityUid> LinkedSources = new();
+
+    /// <summary>
+    /// Counts the amount of times a sink has been invoked for severing the link if this counter gets to high
+    /// The counter is counted down by one every tick if it's higher than 0
+    /// This is for preventing infinite loops
+    /// </summary>
+    [DataField("invokeCounter")]
+    public int InvokeCounter;
+
+    /// <summary>
+    /// How high the invoke counter is allowed to get before the links to the sink are removed and the DeviceLinkOverloadedEvent gets raised
+    /// If the invoke limit is smaller than 1 the sink can't overload
+    /// </summary>
+    [ViewVariables(VVAccess.ReadWrite)]
+    [DataField("invokeLimit")]
+    public int InvokeLimit = 10;
 }

Content.Shared/DeviceLinking/SharedDeviceLinkSystem.cs

@@ -315,6 +315,20 @@ public abstract class SharedDeviceLinkSystem : EntitySystem
             sinkComponent.LinkedSources.Add(sourceUid);
     }
 
+    /// <summary>
+    /// Removes every link from the given sink
+    /// </summary>
+    public void RemoveAllFromSink(EntityUid sinkUid, DeviceLinkSinkComponent? sinkComponent = null)
+    {
+        if (!Resolve(sinkUid, ref sinkComponent))
+            return;
+
+        foreach (var sourceUid in sinkComponent.LinkedSources)
+        {
+            RemoveSinkFromSource(sourceUid, sinkUid, null, sinkComponent);
+        }
+    }
+
     /// <summary>
     /// Removes all links between a source and a sink
     /// </summary>
@@ -332,7 +346,7 @@ public abstract class SharedDeviceLinkSystem : EntitySystem
 
         if (sourceComponent == null && sinkComponent == null)
         {
-            // Both were delted?
+            // Both were deleted?
             return;
         }