Fix a case where a node that closed slightly ahead of other ledgers can

think it's out of sync with the network and cause it to jump backwards one
ledger, causing it to be out of sync because the network was about to catch
up to it.

src/cpp/ripple/LedgerConsensus.cpp

@@ -373,9 +373,12 @@ void LedgerConsensus::checkLCL()
 	uint256 netLgr = mPrevLedgerHash;
 	int netLgrCount = 0;
 
-	uint256 favoredLedger = mPrevLedgerHash; // Don't get stuck one ledger back or jump one forward
+	uint256 favoredLedger = mPrevLedgerHash;			// Don't jump forward
+	uint256 priorLedger;
+	if (mHaveCorrectLCL)
+		priorLedger = mPreviousLedger->getParentHash();	// don't jump back
 	boost::unordered_map<uint256, currentValidationCount> vals =
-		theApp->getValidations().getCurrentValidations(favoredLedger);
+		theApp->getValidations().getCurrentValidations(favoredLedger, priorLedger);
 
 	typedef std::map<uint256, currentValidationCount>::value_type u256_cvc_pair;
 	BOOST_FOREACH(u256_cvc_pair& it, vals)

src/cpp/ripple/LedgerTiming.h

@@ -7,11 +7,11 @@
 // The number of seconds a validation remains current after its ledger's close time
 // This is a safety to protect against very old validations and the time it takes to adjust
 // the close time accuracy window
-#	define LEDGER_VAL_INTERVAL		600
+#	define LEDGER_VAL_INTERVAL		300
 
 // The number of seconds before a close time that we consider a validation acceptable
 // This protects against extreme clock errors
-#	define LEDGER_EARLY_INTERVAL	240
+#	define LEDGER_EARLY_INTERVAL	180
 
 // The number of milliseconds we wait minimum to ensure participation
 #	define LEDGER_MIN_CONSENSUS		2000

src/cpp/ripple/NetworkOPs.cpp

@@ -685,7 +685,7 @@ bool NetworkOPs::checkLastClosedLedger(const std::vector<Peer::pointer>& peerLis
 	boost::unordered_map<uint256, ValidationCount> ledgers;
 	{
 		boost::unordered_map<uint256, currentValidationCount> current =
-			theApp->getValidations().getCurrentValidations(closedLedger);
+			theApp->getValidations().getCurrentValidations(closedLedger, prevClosedLedger);
 		typedef std::map<uint256, currentValidationCount>::value_type u256_cvc_pair;
 		BOOST_FOREACH(const u256_cvc_pair& it, current)
 		{

src/cpp/ripple/ValidationCollection.cpp

@@ -228,10 +228,11 @@ std::list<SerializedValidation::pointer> ValidationCollection::getCurrentTrusted
 }
 
 boost::unordered_map<uint256, currentValidationCount>
-ValidationCollection::getCurrentValidations(uint256 currentLedger)
+ValidationCollection::getCurrentValidations(uint256 currentLedger, uint256 priorLedger)
 {
     uint32 cutoff = theApp->getOPs().getNetworkTimeNC() - LEDGER_VAL_INTERVAL;
     bool valCurrentLedger = currentLedger.isNonZero();
+    bool valPriorLedger = priorLedger.isNonZero();
 
 	boost::unordered_map<uint256, currentValidationCount> ret;
 
@@ -250,7 +251,8 @@ ValidationCollection::getCurrentValidations(uint256 currentLedger)
 		}
 		else
 		{ // contains a live record
-			bool countPreferred = valCurrentLedger && it->second->isPreviousHash(currentLedger);
+			bool countPreferred = (valCurrentLedger && it->second->isPreviousHash(currentLedger)) ||
+				(valPriorLedger && (it->second->getLedgerHash() == priorLedger));
 			tLog(countPreferred, lsDEBUG) << "Counting for " << currentLedger << " not " << it->second->getLedgerHash();
 			currentValidationCount& p = countPreferred ? ret[currentLedger] : ret[it->second->getLedgerHash()];
 

src/cpp/ripple/ValidationCollection.h

@@ -47,7 +47,9 @@ public:
 	int getNodesAfter(const uint256& ledger);
 	int getLoadRatio(bool overLoaded);
 
-	boost::unordered_map<uint256, currentValidationCount> getCurrentValidations(uint256 currentLedger);
+	boost::unordered_map<uint256, currentValidationCount> getCurrentValidations(
+		uint256 currentLedger, uint256 previousLedger);
+
 	std::list<SerializedValidation::pointer> getCurrentTrustedValidations();
 
 	void tune(int size, int age);