// PutTransactions stores the transactions in the given database
func PutTransactions(db ethdb.Database, block *types.Block, txs types.Transactions) error {
batch := db.NewBatch()
for i, tx := range block.Transactions() {
rlpEnc, err := rlp.EncodeToBytes(tx)
if err != nil {
return fmt.Errorf("failed encoding tx: %v", err)
}
batch.Put(tx.Hash().Bytes(), rlpEnc)
var txExtra struct {
BlockHash common.Hash
BlockIndex uint64
Index uint64
}
txExtra.BlockHash = block.Hash()
txExtra.BlockIndex = block.NumberU64()
txExtra.Index = uint64(i)
rlpMeta, err := rlp.EncodeToBytes(txExtra)
if err != nil {
return fmt.Errorf("failed encoding tx meta data: %v", err)
}
batch.Put(append(tx.Hash().Bytes(), 0x0001), rlpMeta)
}
if err := batch.Write(); err != nil {
return fmt.Errorf("failed writing tx to db: %v", err)
}
return nil
}
// insert spawns a new goroutine to run a block insertion into the chain. If the
// block's number is at the same height as the current import phase, if updates
// the phase states accordingly.
func (f *Fetcher) insert(peer string, block *types.Block) {
hash := block.Hash()
// Run the import on a new thread
glog.V(logger.Debug).Infof("Peer %s: importing block #%d [%x]", peer, block.NumberU64(), hash[:4])
go func() {
defer func() { f.done <- hash }()
// If the parent's unknown, abort insertion
parent := f.getBlock(block.ParentHash())
if parent == nil {
return
}
// Quickly validate the header and propagate the block if it passes
if err := f.validateBlock(block, parent); err != nil {
glog.V(logger.Debug).Infof("Peer %s: block #%d [%x] verification failed: %v", peer, block.NumberU64(), hash[:4], err)
f.dropPeer(peer)
return
}
go f.broadcastBlock(block, true)
// Run the actual import and log any issues
if _, err := f.insertChain(types.Blocks{block}); err != nil {
glog.V(logger.Warn).Infof("Peer %s: block #%d [%x] import failed: %v", peer, block.NumberU64(), hash[:4], err)
return
}
// If import succeeded, broadcast the block
go f.broadcastBlock(block, false)
// Invoke the testing hook if needed
if f.importedHook != nil {
f.importedHook(block)
}
}()
}
// PutTransactions stores the transactions in the given database
func PutTransactions(db common.Database, block *types.Block, txs types.Transactions) {
for i, tx := range block.Transactions() {
rlpEnc, err := rlp.EncodeToBytes(tx)
if err != nil {
glog.V(logger.Debug).Infoln("Failed encoding tx", err)
return
}
db.Put(tx.Hash().Bytes(), rlpEnc)
var txExtra struct {
BlockHash common.Hash
BlockIndex uint64
Index uint64
}
txExtra.BlockHash = block.Hash()
txExtra.BlockIndex = block.NumberU64()
txExtra.Index = uint64(i)
rlpMeta, err := rlp.EncodeToBytes(txExtra)
if err != nil {
glog.V(logger.Debug).Infoln("Failed encoding tx meta data", err)
return
}
db.Put(append(tx.Hash().Bytes(), 0x0001), rlpMeta)
}
}
// Creates a new QML Block from a chain block
func NewBlock(block *types.Block) *Block {
if block == nil {
return &Block{}
}
ptxs := make([]*Transaction, len(block.Transactions()))
/*
for i, tx := range block.Transactions() {
ptxs[i] = NewTx(tx)
}
*/
txlist := common.NewList(ptxs)
puncles := make([]*Block, len(block.Uncles()))
/*
for i, uncle := range block.Uncles() {
puncles[i] = NewBlock(types.NewBlockWithHeader(uncle))
}
*/
ulist := common.NewList(puncles)
return &Block{
ref: block, Size: block.Size().String(),
Number: int(block.NumberU64()), GasUsed: block.GasUsed().String(),
GasLimit: block.GasLimit().String(), Hash: block.Hash().Hex(),
Transactions: txlist, Uncles: ulist,
Time: block.Time(),
Coinbase: block.Coinbase().Hex(),
PrevHash: block.ParentHash().Hex(),
Bloom: common.ToHex(block.Bloom().Bytes()),
Raw: block.String(),
}
}
// returns the lowers possible price with which a tx was or could have been included
func (self *GasPriceOracle) lowestPrice(block *types.Block) *big.Int {
gasUsed := new(big.Int)
receipts := self.eth.BlockProcessor().GetBlockReceipts(block.Hash())
if len(receipts) > 0 {
if cgu := receipts[len(receipts)-1].CumulativeGasUsed; cgu != nil {
gasUsed = receipts[len(receipts)-1].CumulativeGasUsed
}
}
if new(big.Int).Mul(gasUsed, big.NewInt(100)).Cmp(new(big.Int).Mul(block.GasLimit(),
big.NewInt(int64(self.eth.GpoFullBlockRatio)))) < 0 {
// block is not full, could have posted a tx with MinGasPrice
return self.eth.GpoMinGasPrice
}
txs := block.Transactions()
if len(txs) == 0 {
return self.eth.GpoMinGasPrice
}
// block is full, find smallest gasPrice
minPrice := txs[0].GasPrice()
for i := 1; i < len(txs); i++ {
price := txs[i].GasPrice()
if price.Cmp(minPrice) < 0 {
minPrice = price
}
}
return minPrice
}
// Process processes the state changes according to the Ethereum rules by running
// the transaction messages using the statedb and applying any rewards to both
// the processor (coinbase) and any included uncles.
//
// Process returns the receipts and logs accumulated during the process and
// returns the amount of gas that was used in the process. If any of the
// transactions failed to execute due to insufficient gas it will return an error.
func (p *StateProcessor) Process(block *types.Block, statedb *state.StateDB, cfg vm.Config) (types.Receipts, vm.Logs, *big.Int, error) {
var (
receipts types.Receipts
totalUsedGas = big.NewInt(0)
err error
header = block.Header()
allLogs vm.Logs
gp = new(GasPool).AddGas(block.GasLimit())
)
// Mutate the the block and state according to any hard-fork specs
if p.config.DAOForkSupport && p.config.DAOForkBlock != nil && p.config.DAOForkBlock.Cmp(block.Number()) == 0 {
ApplyDAOHardFork(statedb)
}
// Iterate over and process the individual transactions
for i, tx := range block.Transactions() {
statedb.StartRecord(tx.Hash(), block.Hash(), i)
receipt, logs, _, err := ApplyTransaction(p.config, p.bc, gp, statedb, header, tx, totalUsedGas, cfg)
if err != nil {
return nil, nil, totalUsedGas, err
}
receipts = append(receipts, receipt)
allLogs = append(allLogs, logs...)
}
AccumulateRewards(statedb, header, block.Uncles())
return receipts, allLogs, totalUsedGas, err
}
// SendNewBlock propagates an entire block to a remote peer.
func (p *peer) SendNewBlock(block *types.Block, td *big.Int) error {
propBlockOutPacketsMeter.Mark(1)
propBlockOutTrafficMeter.Mark(block.Size().Int64())
p.knownBlocks.Add(block.Hash())
return p2p.Send(p.rw, NewBlockMsg, []interface{}{block, td})
}
// reportBlock reports the given block and error using the canonical block
// reporting tool. Reporting the block to the service is handled in a separate
// goroutine.
func reportBlock(block *types.Block, err error) {
if glog.V(logger.Error) {
glog.Errorf("Bad block #%v (%s)\n", block.Number(), block.Hash().Hex())
glog.Errorf(" %v", err)
}
go ReportBlock(block, err)
}
// ResetWithGenesisBlock purges the entire blockchain, restoring it to the
// specified genesis state.
func (bc *ChainManager) ResetWithGenesisBlock(genesis *types.Block) {
bc.mu.Lock()
defer bc.mu.Unlock()
// Dump the entire block chain and purge the caches
for block := bc.currentBlock; block != nil; block = bc.GetBlock(block.ParentHash()) {
DeleteBlock(bc.chainDb, block.Hash())
}
bc.headerCache.Purge()
bc.bodyCache.Purge()
bc.bodyRLPCache.Purge()
bc.blockCache.Purge()
bc.futureBlocks.Purge()
// Prepare the genesis block and reinitialize the chain
if err := WriteTd(bc.chainDb, genesis.Hash(), genesis.Difficulty()); err != nil {
glog.Fatalf("failed to write genesis block TD: %v", err)
}
if err := WriteBlock(bc.chainDb, genesis); err != nil {
glog.Fatalf("failed to write genesis block: %v", err)
}
bc.genesisBlock = genesis
bc.insert(bc.genesisBlock)
bc.currentBlock = bc.genesisBlock
bc.setTotalDifficulty(genesis.Difficulty())
}
// BroadcastBlock will either propagate a block to a subset of it's peers, or
// will only announce it's availability (depending what's requested).
func (pm *ProtocolManager) BroadcastBlock(block *types.Block, propagate bool) {
hash := block.Hash()
peers := pm.peers.PeersWithoutBlock(hash)
// If propagation is requested, send to a subset of the peer
if propagate {
// Calculate the TD of the block (it's not imported yet, so block.Td is not valid)
var td *big.Int
if parent := pm.blockchain.GetBlock(block.ParentHash()); parent != nil {
td = new(big.Int).Add(block.Difficulty(), pm.blockchain.GetTd(block.ParentHash()))
} else {
glog.V(logger.Error).Infof("propagating dangling block #%d [%x]", block.NumberU64(), hash[:4])
return
}
// Send the block to a subset of our peers
transfer := peers[:int(math.Sqrt(float64(len(peers))))]
for _, peer := range transfer {
peer.SendNewBlock(block, td)
}
glog.V(logger.Detail).Infof("propagated block %x to %d peers in %v", hash[:4], len(transfer), time.Since(block.ReceivedAt))
}
// Otherwise if the block is indeed in out own chain, announce it
if pm.blockchain.HasBlock(hash) {
for _, peer := range peers {
if peer.version < eth62 {
peer.SendNewBlockHashes61([]common.Hash{hash})
} else {
peer.SendNewBlockHashes([]common.Hash{hash}, []uint64{block.NumberU64()})
}
}
glog.V(logger.Detail).Infof("announced block %x to %d peers in %v", hash[:4], len(peers), time.Since(block.ReceivedAt))
}
}
func (self *BlockProcessor) ApplyTransactions(gp GasPool, statedb *state.StateDB, block *types.Block, txs types.Transactions, transientProcess bool) (types.Receipts, error) {
var (
receipts types.Receipts
totalUsedGas = big.NewInt(0)
err error
cumulativeSum = new(big.Int)
header = block.Header()
)
for i, tx := range txs {
statedb.StartRecord(tx.Hash(), block.Hash(), i)
receipt, txGas, err := self.ApplyTransaction(gp, statedb, header, tx, totalUsedGas, transientProcess)
if err != nil {
return nil, err
}
if err != nil {
glog.V(logger.Core).Infoln("TX err:", err)
}
receipts = append(receipts, receipt)
cumulativeSum.Add(cumulativeSum, new(big.Int).Mul(txGas, tx.GasPrice()))
}
if block.GasUsed().Cmp(totalUsedGas) != 0 {
return nil, ValidationError(fmt.Sprintf("gas used error (%v / %v)", block.GasUsed(), totalUsedGas))
}
if transientProcess {
go self.eventMux.Post(PendingBlockEvent{block, statedb.Logs()})
}
return receipts, err
}
func (self *Filter) getLogs(start, end uint64) (logs vm.Logs) {
var block *types.Block
for i := start; i <= end; i++ {
hash := core.GetCanonicalHash(self.db, i)
if hash != (common.Hash{}) {
block = core.GetBlock(self.db, hash)
} else { // block not found
return logs
}
// Use bloom filtering to see if this block is interesting given the
// current parameters
if self.bloomFilter(block) {
// Get the logs of the block
var (
receipts = core.GetBlockReceipts(self.db, block.Hash())
unfiltered vm.Logs
)
for _, receipt := range receipts {
unfiltered = append(unfiltered, receipt.Logs...)
}
logs = append(logs, self.FilterLogs(unfiltered)...)
}
}
return logs
}
// insert injects a new head block into the current block chain. This method
// assumes that the block is indeed a true head. It will also reset the head
// header and the head fast sync block to this very same block if they are older
// or if they are on a different side chain.
//
// Note, this function assumes that the `mu` mutex is held!
func (bc *BlockChain) insert(block *types.Block) {
// If the block is on a side chain or an unknown one, force other heads onto it too
updateHeads := GetCanonicalHash(bc.chainDb, block.NumberU64()) != block.Hash()
// Add the block to the canonical chain number scheme and mark as the head
if err := WriteCanonicalHash(bc.chainDb, block.Hash(), block.NumberU64()); err != nil {
glog.Fatalf("failed to insert block number: %v", err)
}
if err := WriteHeadBlockHash(bc.chainDb, block.Hash()); err != nil {
glog.Fatalf("failed to insert head block hash: %v", err)
}
bc.currentBlock = block
// If the block is better than out head or is on a different chain, force update heads
if updateHeads {
if err := WriteHeadHeaderHash(bc.chainDb, block.Hash()); err != nil {
glog.Fatalf("failed to insert head header hash: %v", err)
}
bc.currentHeader = block.Header()
if err := WriteHeadFastBlockHash(bc.chainDb, block.Hash()); err != nil {
glog.Fatalf("failed to insert head fast block hash: %v", err)
}
bc.currentFastBlock = block
}
}
func blockRecovery(ctx *cli.Context) {
utils.CheckLegalese(ctx.GlobalString(utils.DataDirFlag.Name))
arg := ctx.Args().First()
if len(ctx.Args()) < 1 && len(arg) > 0 {
glog.Fatal("recover requires block number or hash")
}
cfg := utils.MakeEthConfig(ClientIdentifier, nodeNameVersion, ctx)
utils.CheckLegalese(cfg.DataDir)
blockDb, err := ethdb.NewLDBDatabase(filepath.Join(cfg.DataDir, "blockchain"), cfg.DatabaseCache)
if err != nil {
glog.Fatalln("could not open db:", err)
}
var block *types.Block
if arg[0] == '#' {
block = core.GetBlockByNumber(blockDb, common.String2Big(arg[1:]).Uint64())
} else {
block = core.GetBlockByHash(blockDb, common.HexToHash(arg))
}
if block == nil {
glog.Fatalln("block not found. Recovery failed")
}
err = core.WriteHead(blockDb, block)
if err != nil {
glog.Fatalln("block write err", err)
}
glog.Infof("Recovery succesful. New HEAD %x\n", block.Hash())
}
func sendBadBlockReport(block *types.Block, err error) {
if !EnableBadBlockReporting {
return
}
var (
blockRLP, _ = rlp.EncodeToBytes(block)
params = map[string]interface{}{
"block": common.Bytes2Hex(blockRLP),
"blockHash": block.Hash().Hex(),
"errortype": err.Error(),
"client": "go",
}
)
if !block.ReceivedAt.IsZero() {
params["receivedAt"] = block.ReceivedAt.UTC().String()
}
if p, ok := block.ReceivedFrom.(*peer); ok {
params["receivedFrom"] = map[string]interface{}{
"enode": fmt.Sprintf("enode://%x@%v", p.ID(), p.RemoteAddr()),
"name": p.Name(),
"protocolVersion": p.version,
}
}
jsonStr, _ := json.Marshal(map[string]interface{}{"method": "eth_badBlock", "id": "1", "jsonrpc": "2.0", "params": []interface{}{params}})
client := http.Client{Timeout: 8 * time.Second}
resp, err := client.Post(badBlocksURL, "application/json", bytes.NewReader(jsonStr))
if err != nil {
glog.V(logger.Debug).Infoln(err)
return
}
glog.V(logger.Debug).Infof("Bad Block Report posted (%d)", resp.StatusCode)
resp.Body.Close()
}
// enqueue schedules a new future import operation, if the block to be imported
// has not yet been seen.
func (f *Fetcher) enqueue(peer string, block *types.Block) {
hash := block.Hash()
// Ensure the peer isn't DOSing us
count := f.queues[peer] + 1
if count > blockLimit {
glog.V(logger.Debug).Infof("Peer %s: discarded block #%d [%x], exceeded allowance (%d)", peer, block.NumberU64(), hash.Bytes()[:4], blockLimit)
return
}
// Discard any past or too distant blocks
if dist := int64(block.NumberU64()) - int64(f.chainHeight()); dist < -maxUncleDist || dist > maxQueueDist {
glog.V(logger.Debug).Infof("Peer %s: discarded block #%d [%x], distance %d", peer, block.NumberU64(), hash.Bytes()[:4], dist)
return
}
// Schedule the block for future importing
if _, ok := f.queued[hash]; !ok {
op := &inject{
origin: peer,
block: block,
}
f.queues[peer] = count
f.queued[hash] = op
f.queue.Push(op, -float32(block.NumberU64()))
if glog.V(logger.Debug) {
glog.Infof("Peer %s: queued block #%d [%x], total %v", peer, block.NumberU64(), hash.Bytes()[:4], f.queue.Size())
}
}
}
// makeCurrent creates a new environment for the current cycle.
func (self *worker) makeCurrent(parent *types.Block, header *types.Header) {
state := state.New(parent.Root(), self.eth.ChainDb())
work := &Work{
state: state,
ancestors: set.New(),
family: set.New(),
uncles: set.New(),
header: header,
coinbase: state.GetOrNewStateObject(self.coinbase),
createdAt: time.Now(),
}
// when 08 is processed ancestors contain 07 (quick block)
for _, ancestor := range self.chain.GetBlocksFromHash(parent.Hash(), 7) {
for _, uncle := range ancestor.Uncles() {
work.family.Add(uncle.Hash())
}
work.family.Add(ancestor.Hash())
work.ancestors.Add(ancestor.Hash())
}
accounts, _ := self.eth.AccountManager().Accounts()
// Keep track of transactions which return errors so they can be removed
work.remove = set.New()
work.tcount = 0
work.ignoredTransactors = set.New()
work.lowGasTransactors = set.New()
work.ownedAccounts = accountAddressesSet(accounts)
if self.current != nil {
work.localMinedBlocks = self.current.localMinedBlocks
}
self.current = work
}
// makeChain creates a chain of n blocks starting at and including parent.
// the returned hash chain is ordered head->parent. In addition, every 3rd block
// contains a transaction and every 5th an uncle to allow testing correct block
// reassembly.
func makeChain(n int, seed byte, parent *types.Block) ([]common.Hash, map[common.Hash]*types.Block) {
blocks, _ := core.GenerateChain(nil, parent, testdb, n, func(i int, block *core.BlockGen) {
block.SetCoinbase(common.Address{seed})
// If the block number is multiple of 3, send a bonus transaction to the miner
if parent == genesis && i%3 == 0 {
tx, err := types.NewTransaction(block.TxNonce(testAddress), common.Address{seed}, big.NewInt(1000), params.TxGas, nil, nil).SignECDSA(testKey)
if err != nil {
panic(err)
}
block.AddTx(tx)
}
// If the block number is a multiple of 5, add a bonus uncle to the block
if i%5 == 0 {
block.AddUncle(&types.Header{ParentHash: block.PrevBlock(i - 1).Hash(), Number: big.NewInt(int64(i - 1))})
}
})
hashes := make([]common.Hash, n+1)
hashes[len(hashes)-1] = parent.Hash()
blockm := make(map[common.Hash]*types.Block, n+1)
blockm[parent.Hash()] = parent
for i, b := range blocks {
hashes[len(hashes)-i-2] = b.Hash()
blockm[b.Hash()] = b
}
return hashes, blockm
}
func (bc *ChainManager) write(block *types.Block) {
enc, _ := rlp.EncodeToBytes((*types.StorageBlock)(block))
key := append(blockHashPre, block.Hash().Bytes()...)
bc.blockDb.Put(key, enc)
// Push block to cache
bc.cache.Push(block)
}
// GetLogs returns the logs of the given block. This method is using a two step approach
// where it tries to get it from the (updated) method which gets them from the receipts or
// the depricated way by re-processing the block.
func (sm *BlockProcessor) GetLogs(block *types.Block) (logs state.Logs, err error) {
receipts := GetBlockReceipts(sm.chainDb, block.Hash())
// coalesce logs
for _, receipt := range receipts {
logs = append(logs, receipt.Logs()...)
}
return logs, nil
}
// WriteCanonNumber writes the canonical hash for the given block
func WriteCanonNumber(db common.Database, block *types.Block) error {
key := append(blockNumPre, block.Number().Bytes()...)
err := db.Put(key, block.Hash().Bytes())
if err != nil {
return err
}
return nil
}
// WriteBlock serializes a block into the database, header and body separately.
func WriteBlock(db ethdb.Database, block *types.Block) error {
// Store the body first to retain database consistency
if err := WriteBody(db, block.Hash(), block.Body()); err != nil {
return err
}
// Store the header too, signaling full block ownership
if err := WriteHeader(db, block.Header()); err != nil {
return err
}
return nil
}
func (bc *ChainManager) write(block *types.Block) {
enc, _ := rlp.EncodeToBytes((*types.StorageBlock)(block))
key := append(blockHashPre, block.Hash().Bytes()...)
err := bc.blockDb.Put(key, enc)
if err != nil {
glog.Fatal("db write fail:", err)
}
// Push block to cache
bc.cache.Push(block)
}
// WriteHead force writes the current head
func WriteHead(db common.Database, block *types.Block) error {
err := WriteCanonNumber(db, block)
if err != nil {
return err
}
err = db.Put([]byte("LastBlock"), block.Hash().Bytes())
if err != nil {
return err
}
return nil
}
// WriteHead force writes the current head
func WriteHead(db common.Database, block *types.Block) error {
key := append(blockNumPre, block.Number().Bytes()...)
err := db.Put(key, block.Hash().Bytes())
if err != nil {
return err
}
err = db.Put([]byte("LastBlock"), block.Hash().Bytes())
if err != nil {
return err
}
return nil
}
func makeHeader(parent *types.Block, state *state.StateDB) *types.Header {
time := parent.Time() + 10 // block time is fixed at 10 seconds
return &types.Header{
Root: state.Root(),
ParentHash: parent.Hash(),
Coinbase: parent.Coinbase(),
Difficulty: CalcDifficulty(int64(time), int64(parent.Time()), parent.Difficulty()),
GasLimit: CalcGasLimit(parent),
GasUsed: new(big.Int),
Number: new(big.Int).Add(parent.Number(), common.Big1),
Time: uint64(time),
}
}
func (bc *ChainManager) write(block *types.Block) {
tstart := time.Now()
enc, _ := rlp.EncodeToBytes((*types.StorageBlock)(block))
key := append(blockHashPre, block.Hash().Bytes()...)
err := bc.blockDb.Put(key, enc)
if err != nil {
glog.Fatal("db write fail:", err)
}
if glog.V(logger.Debug) {
glog.Infof("wrote block #%v %s. Took %v\n", block.Number(), common.PP(block.Hash().Bytes()), time.Since(tstart))
}
}
// makeChain creates a chain of n blocks starting at and including parent.
// the returned hash chain is ordered head->parent.
func makeChain(n int, seed byte, parent *types.Block) ([]common.Hash, map[common.Hash]*types.Block) {
blocks := core.GenerateChain(parent, testdb, n, func(i int, gen *core.BlockGen) {
gen.SetCoinbase(common.Address{seed})
})
hashes := make([]common.Hash, n+1)
hashes[len(hashes)-1] = parent.Hash()
blockm := make(map[common.Hash]*types.Block, n+1)
blockm[parent.Hash()] = parent
for i, b := range blocks {
hashes[len(hashes)-i-2] = b.Hash()
blockm[b.Hash()] = b
}
return hashes, blockm
}
// Process block will attempt to process the given block's transactions and applies them
// on top of the block's parent state (given it exists) and will return wether it was
// successful or not.
func (sm *BlockProcessor) Process(block *types.Block) (logs state.Logs, receipts types.Receipts, err error) {
// Processing a blocks may never happen simultaneously
sm.mutex.Lock()
defer sm.mutex.Unlock()
if sm.bc.HasBlock(block.Hash()) {
return nil, nil, &KnownBlockError{block.Number(), block.Hash()}
}
if !sm.bc.HasBlock(block.ParentHash()) {
return nil, nil, ParentError(block.ParentHash())
}
parent := sm.bc.GetBlock(block.ParentHash())
return sm.processWithParent(block, parent)
}
func makeChainWithDiff(genesis *types.Block, d []int, seed byte) []*types.Block {
var chain []*types.Block
for i, difficulty := range d {
header := &types.Header{Number: big.NewInt(int64(i + 1)), Difficulty: big.NewInt(int64(difficulty))}
block := types.NewBlockWithHeader(header)
copy(block.HeaderHash[:2], []byte{byte(i + 1), seed})
if i == 0 {
block.ParentHeaderHash = genesis.Hash()
} else {
copy(block.ParentHeaderHash[:2], []byte{byte(i), seed})
}
chain = append(chain, block)
}
return chain
}