X-Git-Url: http://git.osdn.net/view?a=blobdiff_plain;f=protocol%2Fprotocol.go;h=d7ea94484e8986833e1f2143f3b95e2fcd524dac;hb=4bc8c34936504eb903d2e8b5cf78473d41681b12;hp=80cb53a1ac5645080734e13fa1d353b3b89c3102;hpb=3bf61490e8df4a17777877b56176ce608f4ccc26;p=bytom%2Fvapor.git

diff --git a/protocol/protocol.go b/protocol/protocol.go
index 80cb53a1..d7ea9448 100644
--- a/protocol/protocol.go
+++ b/protocol/protocol.go
@@ -13,7 +13,10 @@ import (
 	"github.com/vapor/protocol/state"
 )
 
-const maxProcessBlockChSize = 1024
+const (
+	maxProcessBlockChSize = 1024
+	maxKnownTxs           = 32768 // Maximum transactions hashes to keep in the known list (prevent DOS)
+)
 
 // Chain provides functions for working with the Bytom block chain.
 type Chain struct {
@@ -28,10 +31,13 @@ type Chain struct {
 	cond               sync.Cond
 	bestBlockHeader    *types.BlockHeader // the last block on current main chain
 	lastIrrBlockHeader *types.BlockHeader // the last irreversible block
+
+	knownTxs *common.OrderedSet
 }
 
 // NewChain returns a new Chain using store as the underlying storage.
 func NewChain(store Store, txPool *TxPool, eventDispatcher *event.Dispatcher) (*Chain, error) {
+	knownTxs, _ := common.NewOrderedSet(maxKnownTxs)
 	c := &Chain{
 		orphanManage:    NewOrphanManage(),
 		txPool:          txPool,
@@ -39,6 +45,7 @@ func NewChain(store Store, txPool *TxPool, eventDispatcher *event.Dispatcher) (*
 		signatureCache:  common.NewCache(maxSignatureCacheSize),
 		eventDispatcher: eventDispatcher,
 		processBlockCh:  make(chan *processBlockMsg, maxProcessBlockChSize),
+		knownTxs:        knownTxs,
 	}
 	c.cond.L = new(sync.Mutex)
 
@@ -143,10 +150,9 @@ func (c *Chain) InMainChain(hash bc.Hash) bool {
 func (c *Chain) traceLongestChainTail(blockHeader *types.BlockHeader) (*types.BlockHeader, error) {
 	longestTail, workQueue := blockHeader, []*types.BlockHeader{blockHeader}
 
-	for len(workQueue) > 0 {
+	for ; len(workQueue) > 0; workQueue = workQueue[1:] {
 		currentHeader := workQueue[0]
 		currentHash := currentHeader.Hash()
-		workQueue = workQueue[1:]
 		hashes, err := c.store.GetBlockHashesByHeight(currentHeader.Height + 1)
 		if err != nil {
 			return nil, err
@@ -166,6 +172,16 @@ func (c *Chain) traceLongestChainTail(blockHeader *types.BlockHeader) (*types.Bl
 	return longestTail, nil
 }
 
+func (c *Chain) hasSeenTx(tx *types.Tx) bool {
+	return c.knownTxs.Has(tx.ID.String())
+}
+
+func (c *Chain) markTransactions(txs ...*types.Tx) {
+	for _, tx := range txs {
+		c.knownTxs.Add(tx.ID.String())
+	}
+}
+
 // This function must be called with mu lock in above level
 func (c *Chain) setState(blockHeader, irrBlockHeader *types.BlockHeader, mainBlockHeaders []*types.BlockHeader, view *state.UtxoViewpoint, consensusResults []*state.ConsensusResult) error {
 	if err := c.store.SaveChainStatus(blockHeader, irrBlockHeader, mainBlockHeaders, view, consensusResults); err != nil {