Closes #3134 - Least Authority Issue E

CTxMemPool::check() does nothing when turned on, due to overflow.

src/txmempool.h

@@ -161,7 +161,7 @@ public:
      * check does nothing.
      */
     void check(const CCoinsViewCache *pcoins) const;
-    void setSanityCheck(double dFrequency = 1.0) { nCheckFrequency = dFrequency * 4294967296.0; }
+    void setSanityCheck(double dFrequency = 1.0) { nCheckFrequency = static_cast<uint32_t>(dFrequency * 4294967295.0); }
 
     bool addUnchecked(const uint256& hash, const CTxMemPoolEntry &entry, bool fCurrentEstimate = true);
     void remove(const CTransaction &tx, std::list<CTransaction>& removed, bool fRecursive = false);
@@ -219,6 +219,11 @@ public:
     bool ReadFeeEstimates(CAutoFile& filein);
 
     size_t DynamicMemoryUsage() const;
+
+    /** Return nCheckFrequency */
+    uint32_t GetCheckFrequency() const {
+        return nCheckFrequency;
+    }
 };
 
 /**