Fix mempool fees variables (#141)

The old variables in the memory pool would incorrectly
eliminate transactions send over sendrawtransaction that
had high fees while also always rejecting high priority
transactions. The minimum relay fee has been reinstated,
while the threshold fee now correctly refers to tickets.

mempool.go

@@ -79,19 +79,19 @@ const (
 	// is also used to help determine if a transaction is considered dust
 	// and as a base for calculating minimum required fees per KB for larger
 	// transactions.  This value is in Atom/1000 bytes.
-	minTxRelayFeeMainNet = 1e5
+	minTxRelayFeeMainNet = 1e6
 
 	// minTxRelayFeeTestNet is the minimum relay fee for the Test and Simulation
 	// networks.
 	minTxRelayFeeTestNet = 1e3
 
-	// minTxFeeForMempoolMainNet is the minimum fee per KB in atoms that is
-	// required for a transaction to enter the mempool on MainNet.
-	minTxFeeForMempoolMainNet = 1e6
+	// minTicketFeeMainNet is the minimum fee per KB in atoms that is
+	// required for a ticket to enter the mempool on MainNet.
+	minTicketFeeMainNet = 1e6
 
-	// minTxFeeForMempoolMainNet is the minimum fee per KB in atoms that is
-	// required for a transaction to enter the mempool on TestNet or SimNet.
-	minTxFeeForMempoolTestNet = 1e2
+	// minTicketFeeTestNet is the minimum fee per KB in atoms that is
+	// required for a ticekt to enter the mempool on TestNet or SimNet.
+	minTicketFeeTestNet = 1e3
 
 	// maxSSGensDoubleSpends is the maximum number of SSGen double spends
 	// allowed in the pool.
@@ -1719,6 +1719,7 @@ func (mp *txMemPool) maybeAcceptTransaction(tx *dcrutil.Tx, isNew,
 	// which is more desirable.  Therefore, as long as the size of the
 	// transaction does not exceeed 1000 less than the reserved space for
 	// high-priority transactions, don't require a fee for it.
+	// This applies to non-stake transactions only.
 	serializedSize := int64(tx.MsgTx().SerializeSize())
 	minFee := calcMinRequiredTxRelayFee(serializedSize, int64(minRelayTxFee))
 	if txType == stake.TxTypeRegular { // Non-stake only
@@ -1730,45 +1731,11 @@ func (mp *txMemPool) maybeAcceptTransaction(tx *dcrutil.Tx, isNew,
 		}
 	}
 
-	// Set an absolute threshold for rejection and obey it. This prevents
-	// unnecessary transaction spam. We only enforce this for transactions
-	// we expect to have fees. Votes are mandatory, so we skip the check
-	// on them.
-	var feeThreshold int64
-	switch {
-	case mp.server.chainParams == &chaincfg.MainNetParams:
-		feeThreshold = minTxFeeForMempoolMainNet
-	case mp.server.chainParams == &chaincfg.TestNetParams:
-		feeThreshold = minTxFeeForMempoolTestNet
-	default:
-		feeThreshold = minTxFeeForMempoolTestNet
-	}
-
-	minThreshold := calcMinRequiredTxRelayFee(serializedSize, feeThreshold)
-	if (txFee < minThreshold) && txType != stake.TxTypeSSGen {
-		str := fmt.Sprintf("transaction %v has a %v fee which "+
-			"is under the required threshold amount of %d", txHash, txFee,
-			minThreshold)
-		return nil, txRuleError(wire.RejectInsufficientFee, str)
-	}
-
-	// Check whether allowHighFees is set to false (default), if so, then make sure
-	// the current fee is sensible.  100 * above the minimum fee/kb seems to be a
-	// reasonable amount to check.  If people would like to avoid this check
-	// then they can AllowHighFees = true
-	if !allowHighFees {
-		maxFee := calcMinRequiredTxRelayFee(serializedSize*100, int64(minRelayTxFee))
-		if txFee > maxFee {
-			err = fmt.Errorf("transaction %v has %v fee which is above the "+
-				"allowHighFee check threshold amount of %v", txHash,
-				txFee, maxFee)
-			return nil, err
-		}
-	}
 	// Require that free transactions have sufficient priority to be mined
 	// in the next block.  Transactions which are being added back to the
 	// memory pool from blocks that have been disconnected during a reorg
 	// are exempted.
+	// This applies to non-stake transactions only.
 	if isNew && !cfg.NoRelayPriority && txFee < minFee &&
 		txType == stake.TxTypeRegular {
 		txD := &TxDesc{
@@ -1788,6 +1755,7 @@ func (mp *txMemPool) maybeAcceptTransaction(tx *dcrutil.Tx, isNew,
 
 	// Free-to-relay transactions are rate limited here to prevent
 	// penny-flooding with tiny transactions as a form of attack.
+	// This applies to non-stake transactions only.
 	if rateLimit && txFee < minFee && txType == stake.TxTypeRegular {
 		nowUnix := time.Now().Unix()
 		// we decay passed data with an exponentially decaying ~10
@@ -1810,6 +1778,44 @@ func (mp *txMemPool) maybeAcceptTransaction(tx *dcrutil.Tx, isNew,
 			cfg.FreeTxRelayLimit*10*1000)
 	}
 
+	// Set an absolute threshold for ticket rejection and obey it. Tickets
+	// are treated differently in the mempool because they have a set
+	// difficulty and generally a window in which they expire.
+	//
+	// This applies to tickets transactions only.
+	var ticketFeeThreshold int64
+	switch {
+	case mp.server.chainParams == &chaincfg.MainNetParams:
+		ticketFeeThreshold = minTicketFeeMainNet
+	case mp.server.chainParams == &chaincfg.TestNetParams:
+		ticketFeeThreshold = minTicketFeeTestNet
+	default:
+		ticketFeeThreshold = minTicketFeeTestNet
+	}
+
+	minTicketFee := calcMinRequiredTxRelayFee(serializedSize, ticketFeeThreshold)
+	if (txFee < minTicketFee) && txType == stake.TxTypeSStx {
+		str := fmt.Sprintf("transaction %v has a %v fee which "+
+			"is under the required threshold amount of %d", txHash, txFee,
+			minTicketFee)
+		return nil, txRuleError(wire.RejectInsufficientFee, str)
+	}
+
+	// Check whether allowHighFees is set to false (default), if so, then make sure
+	// the current fee is sensible.  100 * above the minimum fee/kb seems to be a
+	// reasonable amount to check.  If people would like to avoid this check
+	// then they can AllowHighFees = true
+	if !allowHighFees {
+		maxFee := calcMinRequiredTxRelayFee(serializedSize*100,
+			int64(minRelayTxFee))
+		if txFee > maxFee {
+			err = fmt.Errorf("transaction %v has %v fee which is above the "+
+				"allowHighFee check threshold amount of %v", txHash,
+				txFee, maxFee)
+			return nil, err
+		}
+	}
+
 	// Verify crypto signatures for each input and reject the transaction if
 	// any don't verify.
 	err = blockchain.ValidateTransactionScripts(tx, txStore,