Allow morepackets(player) to override the set-back by other checks.

This is meant to prevent packet based speeding, employing micro
violations of other checks, in order to erase the morepackets data.

NCPCore/src/main/java/fr/neatmonster/nocheatplus/checks/moving/MovingData.java

@@ -152,6 +152,19 @@ public static void onReload() {
     public float walkSpeed = 0.0f;
     public float flySpeed = 0.0f;
 
+    /** Count set-back (re-) setting. */
+    private int setBackResetCount = 0;
+    /**
+     * setBackResetCount (incremented) at the time of (re-) setting the ordinary
+     * set-back.
+     */
+    private int setBackResetTime = 0;
+    /**
+     * setBackResetCount (incremented) at the time of (re-) setting the
+     * morepackets set-back.
+     */
+    private int morePacketsSetBackResetTime = 0;
+
     /**
      * Keep track of past moves edge data. First entry always is the last fully
      * processed move, or invalid, even during processing. The currently
@@ -500,6 +513,7 @@ public void setSetBack(final PlayerLocation loc) {
             LocUtil.set(setBack, loc);
         }
         // TODO: Consider adjusting the set-back-y here. Problem: Need to take into account for bounding box (collect max-ground-height needed).
+        setBackResetTime = ++setBackResetCount;
     }
 
     /**
@@ -513,6 +527,7 @@ public void setSetBack(final Location loc) {
         else{
             LocUtil.set(setBack, loc);
         }
+        setBackResetTime = ++setBackResetCount;
     }
 
     /**
@@ -561,6 +576,7 @@ public double getSetBackZ() {
 
     public void setSetBackY(final double y) {
         setBack.setY(y);
+        // (Skip setting/increasing the reset count.)
     }
 
     /**
@@ -595,13 +611,24 @@ public boolean hasMorePacketsSetBack() {
         return morePacketsSetback != null;
     }
 
+    /**
+     * Test if the morepackets set-back is older than the ordinary set-back.
+     * Does not check for existence of either.
+     * 
+     * @return
+     */
+    public boolean isMorePacketsSetBackOldest() {
+        return morePacketsSetBackResetTime < setBackResetTime;
+    }
+
     public final void setMorePacketsSetBack(final PlayerLocation loc) {
         if (morePacketsSetback == null) {
             morePacketsSetback = loc.getLocation();
         }
         else {
             LocUtil.set(morePacketsSetback, loc);
         }
+        morePacketsSetBackResetTime = ++setBackResetCount;
     }
 
     public final void setMorePacketsSetBack(final Location loc) {
@@ -611,6 +638,7 @@ public final void setMorePacketsSetBack(final Location loc) {
         else {
             LocUtil.set(morePacketsSetback, loc);
         }
+        morePacketsSetBackResetTime = ++setBackResetCount;
     }
 
     public Location getMorePacketsSetBack() {

NCPCore/src/main/java/fr/neatmonster/nocheatplus/checks/moving/MovingListener.java

@@ -700,9 +700,18 @@ else if (checkCf) {
         }
 
         // Morepackets.
-        if (newTo == null && cc.morePacketsCheck && !NCPExemptionManager.isExempted(player, CheckType.MOVING_MOREPACKETS) && !player.hasPermission(Permissions.MOVING_MOREPACKETS)) {
-            // If it hasn't been stopped by any other check and is handled by the more packets check, execute it.
-            newTo = morePackets.check(player, pFrom, pTo, data, cc);
+        if (cc.morePacketsCheck && !NCPExemptionManager.isExempted(player, CheckType.MOVING_MOREPACKETS) && !player.hasPermission(Permissions.MOVING_MOREPACKETS)) {
+            // (Always check morepackets, to avoid packet speeding using micro-violations.)
+            final Location mpNewTo = morePackets.check(player, pFrom, pTo, data, cc);
+            if (mpNewTo != null) {
+                // Only override set-back, if the morepackets set-back location is older/-est. 
+                if (newTo == null || data.isMorePacketsSetBackOldest()) {
+                    if (newTo != null && data.debug) {
+                        debug(player, "Override set-back by the older morepackets set-back.");
+                    }
+                    newTo = mpNewTo;
+                }
+            }
         } else {
             // Otherwise we need to clear their data.
             data.clearMorePacketsData();