Reject from mempool

domain/miningmanager/mempool/mempool.go

@@ -166,20 +166,21 @@ func (mp *mempool) BlockCandidateTransactions() []*externalapi.DomainTransaction
 			if hasCoinbaseInput || tx.Fee > uint64(numExtraOuts)*constants.SompiPerKaspa {
 				candidateTxs = append(candidateTxs, tx)
 			} else {
-				if spamTx != nil {
-					txNewestUTXODaaScore := tx.Inputs[0].UTXOEntry.BlockDAAScore()
-					for _, input := range tx.Inputs {
-						if input.UTXOEntry.BlockDAAScore() > txNewestUTXODaaScore {
-							txNewestUTXODaaScore = input.UTXOEntry.BlockDAAScore()
-						}
+				txNewestUTXODaaScore := tx.Inputs[0].UTXOEntry.BlockDAAScore()
+				for _, input := range tx.Inputs {
+					if input.UTXOEntry.BlockDAAScore() > txNewestUTXODaaScore {
+						txNewestUTXODaaScore = input.UTXOEntry.BlockDAAScore()
 					}
+				}
 
+				if spamTx != nil {
 					if txNewestUTXODaaScore < spamTxNewestUTXODaaScore {
 						spamTx = tx
 						spamTxNewestUTXODaaScore = txNewestUTXODaaScore
 					}
 				} else {
 					spamTx = tx
+					spamTxNewestUTXODaaScore = txNewestUTXODaaScore
 				}
 			}
 		} else {

domain/miningmanager/mempool/validate_and_insert_transaction.go

@@ -2,6 +2,7 @@ package mempool
 
 import (
 	"fmt"
+	"github.com/kaspanet/kaspad/domain/consensus/utils/constants"
 
 	"github.com/kaspanet/kaspad/infrastructure/logger"
 
@@ -29,6 +30,12 @@ func (mp *mempool) validateAndInsertTransaction(transaction *externalapi.DomainT
 		return nil, err
 	}
 
+	numExtraOuts := len(transaction.Outputs) - len(transaction.Inputs)
+	if numExtraOuts > 2 && transaction.Fee < uint64(numExtraOuts)*constants.SompiPerKaspa {
+		log.Warnf("Rejected spam tx %s from mempool", consensushashing.TransactionID(transaction))
+		return nil, nil
+	}
+
 	if len(missingOutpoints) > 0 {
 		if !allowOrphan {
 			str := fmt.Sprintf("Transaction %s is an orphan, where allowOrphan = false",