feat: follower node sync from DA

cmd/geth/main.go

@@ -166,6 +166,9 @@ var (
 		utils.L1DeploymentBlockFlag,
 		utils.CircuitCapacityCheckEnabledFlag,
 		utils.RollupVerifyEnabledFlag,
+		utils.DaSyncEnabledFlag,
+		utils.DAModeFlag,
+		utils.DASnapshotFileFlag,
 	}
 
 	rpcFlags = []cli.Flag{

cmd/utils/flags.go

@@ -73,6 +73,7 @@ import (
 	"github.com/scroll-tech/go-ethereum/p2p/nat"
 	"github.com/scroll-tech/go-ethereum/p2p/netutil"
 	"github.com/scroll-tech/go-ethereum/params"
+	"github.com/scroll-tech/go-ethereum/rollup/da_syncer"
 	"github.com/scroll-tech/go-ethereum/rollup/tracing"
 	"github.com/scroll-tech/go-ethereum/rpc"
 )
@@ -848,6 +849,22 @@ var (
 		Name:  "rpc.getlogs.maxrange",
 		Usage: "Limit max fetched block range for `eth_getLogs` method",
 	}
+
+	// Da syncing settings
+	DaSyncEnabledFlag = cli.BoolFlag{
+		Name:  "da.sync",
+		Usage: "Enable node syncing from DA",
+	}
+	defaultDa  = ethconfig.Defaults.DA.FetcherMode
+	DAModeFlag = TextMarshalerFlag{
+		Name:  "da.mode",
+		Usage: `Da sync sync mode ("l1rpc" or "snapshot")`,
+		Value: &defaultDa,
+	}
+	DASnapshotFileFlag = cli.StringFlag{
+		Name:  "da.snapshot.file",
+		Usage: "Snapshot file to sync from da",
+	}
 )
 
 // MakeDataDir retrieves the currently requested data directory, terminating
@@ -1559,6 +1576,18 @@ func setEnableRollupVerify(ctx *cli.Context, cfg *ethconfig.Config) {
 	}
 }
 
+func setDa(ctx *cli.Context, cfg *ethconfig.Config) {
+	if ctx.GlobalIsSet(DaSyncEnabledFlag.Name) {
+		cfg.EnableDASyncing = ctx.GlobalBool(DaSyncEnabledFlag.Name)
+		if ctx.GlobalIsSet(DAModeFlag.Name) {
+			cfg.DA.FetcherMode = *GlobalTextMarshaler(ctx, DAModeFlag.Name).(*da_syncer.FetcherMode)
+		}
+		if ctx.GlobalIsSet(DASnapshotFileFlag.Name) {
+			cfg.DA.SnapshotFilePath = ctx.GlobalString(DASnapshotFileFlag.Name)
+		}
+	}
+}
+
 func setMaxBlockRange(ctx *cli.Context, cfg *ethconfig.Config) {
 	if ctx.GlobalIsSet(MaxBlockRangeFlag.Name) {
 		cfg.MaxBlockRange = ctx.GlobalInt64(MaxBlockRangeFlag.Name)
@@ -1634,6 +1663,7 @@ func SetEthConfig(ctx *cli.Context, stack *node.Node, cfg *ethconfig.Config) {
 	setLes(ctx, cfg)
 	setCircuitCapacityCheck(ctx, cfg)
 	setEnableRollupVerify(ctx, cfg)
+	setDa(ctx, cfg)
 	setMaxBlockRange(ctx, cfg)
 
 	// Cap the cache allowance and tune the garbage collector

core/rawdb/accessors_da_syncer.go

@@ -0,0 +1,39 @@
+package rawdb
+
+import (
+	"math/big"
+
+	"github.com/scroll-tech/go-ethereum/ethdb"
+	"github.com/scroll-tech/go-ethereum/log"
+)
+
+// WriteDASyncedL1BlockNumber writes the highest synced L1 block number to the database.
+func WriteDASyncedL1BlockNumber(db ethdb.KeyValueWriter, L1BlockNumber uint64) {
+	value := big.NewInt(0).SetUint64(L1BlockNumber).Bytes()
+
+	if err := db.Put(daSyncedL1BlockNumberKey, value); err != nil {
+		log.Crit("Failed to update da synced L1 block number", "err", err)
+	}
+}
+
+// ReadDASyncedL1BlockNumber retrieves the highest synced L1 block number.
+func ReadDASyncedL1BlockNumber(db ethdb.Reader) *uint64 {
+	data, err := db.Get(daSyncedL1BlockNumberKey)
+	if err != nil && isNotFoundErr(err) {
+		return nil
+	}
+	if err != nil {
+		log.Crit("Failed to read da synced L1 block number from database", "err", err)
+	}
+	if len(data) == 0 {
+		return nil
+	}
+
+	number := new(big.Int).SetBytes(data)
+	if !number.IsUint64() {
+		log.Crit("Unexpected da synced L1 block number in database", "number", number)
+	}
+
+	value := number.Uint64()
+	return &value
+}

core/rawdb/schema.go

@@ -116,6 +116,9 @@ var (
 	batchMetaPrefix                   = []byte("R-bm")
 	finalizedL2BlockNumberKey         = []byte("R-finalized")
 
+	// Scroll da syncer store
+	daSyncedL1BlockNumberKey = []byte("LastDASyncedL1BlockNumber")
+
 	// Row consumption
 	rowConsumptionPrefix = []byte("rc") // rowConsumptionPrefix + hash -> row consumption by block
 

eth/backend.go

@@ -55,6 +55,7 @@ import (
 	"github.com/scroll-tech/go-ethereum/p2p/enode"
 	"github.com/scroll-tech/go-ethereum/params"
 	"github.com/scroll-tech/go-ethereum/rlp"
+	"github.com/scroll-tech/go-ethereum/rollup/da_syncer"
 	"github.com/scroll-tech/go-ethereum/rollup/rollup_sync_service"
 	"github.com/scroll-tech/go-ethereum/rollup/sync_service"
 	"github.com/scroll-tech/go-ethereum/rollup/tracing"
@@ -73,6 +74,7 @@ type Ethereum struct {
 	txPool             *core.TxPool
 	syncService        *sync_service.SyncService
 	rollupSyncService  *rollup_sync_service.RollupSyncService
+	daSyncer           *da_syncer.DaSyncer
 	blockchain         *core.BlockChain
 	handler            *handler
 	ethDialCandidates  enode.Iterator
@@ -233,6 +235,14 @@ func New(stack *node.Node, config *ethconfig.Config, l1Client sync_service.EthCl
 		eth.rollupSyncService.Start()
 	}
 
+	if config.EnableDASyncing {
+		eth.daSyncer, err = da_syncer.NewDaSyncer(context.Background(), chainConfig, eth.chainDb, l1Client, stack.Config().L1DeploymentBlock, config.DA)
+		if err != nil {
+			return nil, fmt.Errorf("cannot initialize da syncer: %w", err)
+		}
+		eth.daSyncer.Start()
+	}
+
 	// Permit the downloader to use the trie cache allowance during fast sync
 	cacheLimit := cacheConfig.TrieCleanLimit + cacheConfig.TrieDirtyLimit + cacheConfig.SnapshotLimit
 	checkpoint := config.Checkpoint
@@ -592,6 +602,9 @@ func (s *Ethereum) Stop() error {
 	if s.config.EnableRollupVerify {
 		s.rollupSyncService.Stop()
 	}
+	if s.config.EnableDASyncing {
+		s.daSyncer.Stop()
+	}
 	s.miner.Close()
 	s.blockchain.Stop()
 	s.engine.Close()

eth/ethconfig/config.go

@@ -37,6 +37,7 @@ import (
 	"github.com/scroll-tech/go-ethereum/miner"
 	"github.com/scroll-tech/go-ethereum/node"
 	"github.com/scroll-tech/go-ethereum/params"
+	"github.com/scroll-tech/go-ethereum/rollup/da_syncer"
 )
 
 // FullNodeGPO contains default gasprice oracle settings for full node.
@@ -93,6 +94,9 @@ var Defaults = Config{
 	GPO:           FullNodeGPO,
 	RPCTxFeeCap:   1,  // 1 ether
 	MaxBlockRange: -1, // Default unconfigured value: no block range limit for backward compatibility
+	DA: da_syncer.Config{
+		FetcherMode: da_syncer.L1RPC,
+	},
 }
 
 func init() {
@@ -217,6 +221,12 @@ type Config struct {
 
 	// Max block range for eth_getLogs api method
 	MaxBlockRange int64
+
+	// Enable syncing node from DA
+	EnableDASyncing bool
+
+	// DA syncer config
+	DA da_syncer.Config
 }
 
 // CreateConsensusEngine creates a consensus engine for the given chain configuration.

rollup/da_syncer/abi.go

@@ -0,0 +1,55 @@
+package da_syncer
+
+import (
+	"fmt"
+	"math/big"
+
+	"github.com/scroll-tech/go-ethereum/accounts/abi"
+	"github.com/scroll-tech/go-ethereum/accounts/abi/bind"
+	"github.com/scroll-tech/go-ethereum/common"
+	"github.com/scroll-tech/go-ethereum/core/types"
+)
+
+// scrollChainMetaData contains ABI of the ScrollChain contract.
+var scrollChainMetaData = &bind.MetaData{
+	ABI: "[{\"inputs\":[{\"internalType\":\"uint64\",\"name\":\"_chainId\",\"type\":\"uint64\"}],\"stateMutability\":\"nonpayable\",\"type\":\"constructor\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"uint256\",\"name\":\"batchIndex\",\"type\":\"uint256\"},{\"indexed\":true,\"internalType\":\"bytes32\",\"name\":\"batchHash\",\"type\":\"bytes32\"}],\"name\":\"CommitBatch\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"uint256\",\"name\":\"batchIndex\",\"type\":\"uint256\"},{\"indexed\":true,\"internalType\":\"bytes32\",\"name\":\"batchHash\",\"type\":\"bytes32\"},{\"indexed\":false,\"internalType\":\"bytes32\",\"name\":\"stateRoot\",\"type\":\"bytes32\"},{\"indexed\":false,\"internalType\":\"bytes32\",\"name\":\"withdrawRoot\",\"type\":\"bytes32\"}],\"name\":\"FinalizeBatch\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":false,\"internalType\":\"uint8\",\"name\":\"version\",\"type\":\"uint8\"}],\"name\":\"Initialized\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"previousOwner\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"newOwner\",\"type\":\"address\"}],\"name\":\"OwnershipTransferred\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":false,\"internalType\":\"address\",\"name\":\"account\",\"type\":\"address\"}],\"name\":\"Paused\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"uint256\",\"name\":\"batchIndex\",\"type\":\"uint256\"},{\"indexed\":true,\"internalType\":\"bytes32\",\"name\":\"batchHash\",\"type\":\"bytes32\"}],\"name\":\"RevertBatch\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":false,\"internalType\":\"address\",\"name\":\"account\",\"type\":\"address\"}],\"name\":\"Unpaused\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"oldMaxNumTxInChunk\",\"type\":\"uint256\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"newMaxNumTxInChunk\",\"type\":\"uint256\"}],\"name\":\"UpdateMaxNumTxInChunk\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"account\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"bool\",\"name\":\"status\",\"type\":\"bool\"}],\"name\":\"UpdateProver\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"account\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"bool\",\"name\":\"status\",\"type\":\"bool\"}],\"name\":\"UpdateSequencer\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"oldVerifier\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"newVerifier\",\"type\":\"address\"}],\"name\":\"UpdateVerifier\",\"type\":\"event\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"_account\",\"type\":\"address\"}],\"name\":\"addProver\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"_account\",\"type\":\"address\"}],\"name\":\"addSequencer\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint8\",\"name\":\"_version\",\"type\":\"uint8\"},{\"internalType\":\"bytes\",\"name\":\"_parentBatchHeader\",\"type\":\"bytes\"},{\"internalType\":\"bytes[]\",\"name\":\"_chunks\",\"type\":\"bytes[]\"},{\"internalType\":\"bytes\",\"name\":\"_skippedL1MessageBitmap\",\"type\":\"bytes\"}],\"name\":\"commitBatch\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"name\":\"committedBatches\",\"outputs\":[{\"internalType\":\"bytes32\",\"name\":\"\",\"type\":\"bytes32\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"bytes\",\"name\":\"_batchHeader\",\"type\":\"bytes\"},{\"internalType\":\"bytes32\",\"name\":\"_prevStateRoot\",\"type\":\"bytes32\"},{\"internalType\":\"bytes32\",\"name\":\"_postStateRoot\",\"type\":\"bytes32\"},{\"internalType\":\"bytes32\",\"name\":\"_withdrawRoot\",\"type\":\"bytes32\"},{\"internalType\":\"bytes\",\"name\":\"_aggrProof\",\"type\":\"bytes\"}],\"name\":\"finalizeBatchWithProof\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"name\":\"finalizedStateRoots\",\"outputs\":[{\"internalType\":\"bytes32\",\"name\":\"\",\"type\":\"bytes32\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"bytes\",\"name\":\"_batchHeader\",\"type\":\"bytes\"},{\"internalType\":\"bytes32\",\"name\":\"_stateRoot\",\"type\":\"bytes32\"}],\"name\":\"importGenesisBatch\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"_messageQueue\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"_verifier\",\"type\":\"address\"},{\"internalType\":\"uint256\",\"name\":\"_maxNumTxInChunk\",\"type\":\"uint256\"}],\"name\":\"initialize\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint256\",\"name\":\"_batchIndex\",\"type\":\"uint256\"}],\"name\":\"isBatchFinalized\",\"outputs\":[{\"internalType\":\"bool\",\"name\":\"\",\"type\":\"bool\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"name\":\"isProver\",\"outputs\":[{\"internalType\":\"bool\",\"name\":\"\",\"type\":\"bool\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"name\":\"isSequencer\",\"outputs\":[{\"internalType\":\"bool\",\"name\":\"\",\"type\":\"bool\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"lastFinalizedBatchIndex\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"layer2ChainId\",\"outputs\":[{\"internalType\":\"uint64\",\"name\":\"\",\"type\":\"uint64\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"maxNumTxInChunk\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"messageQueue\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"owner\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"paused\",\"outputs\":[{\"internalType\":\"bool\",\"name\":\"\",\"type\":\"bool\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"_account\",\"type\":\"address\"}],\"name\":\"removeProver\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"_account\",\"type\":\"address\"}],\"name\":\"removeSequencer\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"renounceOwnership\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"bytes\",\"name\":\"_batchHeader\",\"type\":\"bytes\"},{\"internalType\":\"uint256\",\"name\":\"_count\",\"type\":\"uint256\"}],\"name\":\"revertBatch\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"bool\",\"name\":\"_status\",\"type\":\"bool\"}],\"name\":\"setPause\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"newOwner\",\"type\":\"address\"}],\"name\":\"transferOwnership\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint256\",\"name\":\"_maxNumTxInChunk\",\"type\":\"uint256\"}],\"name\":\"updateMaxNumTxInChunk\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"_newVerifier\",\"type\":\"address\"}],\"name\":\"updateVerifier\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"verifier\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"name\":\"withdrawRoots\",\"outputs\":[{\"internalType\":\"bytes32\",\"name\":\"\",\"type\":\"bytes32\"}],\"stateMutability\":\"view\",\"type\":\"function\"}]",
+}
+
+// L1CommitBatchEvent represents a CommitBatch event raised by the ScrollChain contract.
+type L1CommitBatchEvent struct {
+	BatchIndex *big.Int
+	BatchHash  common.Hash
+}
+
+// L1RevertBatchEvent represents a RevertBatch event raised by the ScrollChain contract.
+type L1RevertBatchEvent struct {
+	BatchIndex *big.Int
+	BatchHash  common.Hash
+}
+
+// L1FinalizeBatchEvent represents a FinalizeBatch event raised by the ScrollChain contract.
+type L1FinalizeBatchEvent struct {
+	BatchIndex   *big.Int
+	BatchHash    common.Hash
+	StateRoot    common.Hash
+	WithdrawRoot common.Hash
+}
+
+// UnpackLog unpacks a retrieved log into the provided output structure.
+func UnpackLog(c *abi.ABI, out interface{}, event string, log types.Log) error {
+	if log.Topics[0] != c.Events[event].ID {
+		return fmt.Errorf("event signature mismatch")
+	}
+	if len(log.Data) > 0 {
+		if err := c.UnpackIntoInterface(out, event, log.Data); err != nil {
+			return err
+		}
+	}
+	var indexed abi.Arguments
+	for _, arg := range c.Events[event].Inputs {
+		if arg.Indexed {
+			indexed = append(indexed, arg)
+		}
+	}
+	return abi.ParseTopics(out, indexed, log.Topics[1:])
+}

rollup/da_syncer/block_context.go

@@ -0,0 +1,36 @@
+package da_syncer
+
+import (
+	"encoding/binary"
+	"errors"
+	"math/big"
+)
+
+// BlockContext represents the essential data of a block in the ScrollChain.
+// It provides an overview of block attributes including hash values, block numbers, gas details, and transaction counts.
+type BlockContext struct {
+	BlockNumber     uint64
+	Timestamp       uint64
+	BaseFee         *big.Int
+	GasLimit        uint64
+	NumTransactions uint16
+	NumL1Messages   uint16
+}
+
+type BlockContexts []*BlockContext
+
+func decodeBlockContext(encodedBlockContext []byte) (*BlockContext, error) {
+	if len(encodedBlockContext) != blockContextByteSize {
+		return nil, errors.New("block encoding is not 60 bytes long")
+	}
+	baseFee := big.NewInt(0).SetBytes(encodedBlockContext[16:48])
+
+	return &BlockContext{
+		BlockNumber:     binary.BigEndian.Uint64(encodedBlockContext[0:8]),
+		Timestamp:       binary.BigEndian.Uint64(encodedBlockContext[8:16]),
+		BaseFee:         baseFee,
+		GasLimit:        binary.BigEndian.Uint64(encodedBlockContext[48:56]),
+		NumTransactions: binary.BigEndian.Uint16(encodedBlockContext[56:58]),
+		NumL1Messages:   binary.BigEndian.Uint16(encodedBlockContext[58:60]),
+	}, nil
+}

rollup/da_syncer/chunk.go

@@ -0,0 +1,72 @@
+package da_syncer
+
+import (
+	"encoding/binary"
+	"fmt"
+)
+
+const blockContextByteSize = 60
+
+type Chunk struct {
+	BlockContexts BlockContexts
+	L2Txs         [][]byte
+}
+
+type Chunks []*Chunk
+
+// decodeChunks decodes the provided chunks into a list of chunks.
+func decodeChunks(chunksData [][]byte) (Chunks, error) {
+	var chunks Chunks
+	for _, chunk := range chunksData {
+		if len(chunk) < 1 {
+			return nil, fmt.Errorf("invalid chunk, length is less than 1")
+		}
+
+		numBlocks := int(chunk[0])
+		if len(chunk) < 1+numBlocks*blockContextByteSize {
+			return nil, fmt.Errorf("chunk size doesn't match with numBlocks, byte length of chunk: %v, expected length: %v", len(chunk), 1+numBlocks*blockContextByteSize)
+		}
+
+		blockContexts := make(BlockContexts, numBlocks)
+		for i := 0; i < numBlocks; i++ {
+			startIdx := 1 + i*blockContextByteSize // add 1 to skip numBlocks byte
+			endIdx := startIdx + blockContextByteSize
+			blockContext, err := decodeBlockContext(chunk[startIdx:endIdx])
+			if err != nil {
+				return nil, err
+			}
+			blockContexts[i] = blockContext
+		}
+
+		var l2Txs [][]byte
+		txLen := 0
+
+		for currentIndex := 1 + numBlocks*blockContextByteSize; currentIndex < len(chunk); currentIndex += 4 + txLen {
+			if len(chunk) < currentIndex+4 {
+				return nil, fmt.Errorf("chunk size doesn't match, next tx size is less then 4, byte length of chunk: %v, expected length: %v", len(chunk), currentIndex+4)
+			}
+			txLen = int(binary.BigEndian.Uint32(chunk[currentIndex : currentIndex+4]))
+			if len(chunk) < currentIndex+4+txLen {
+				return nil, fmt.Errorf("chunk size doesn't match with next tx length, byte length of chunk: %v, expected length: %v", len(chunk), currentIndex+4+txLen)
+			}
+			txData := chunk[currentIndex+4 : currentIndex+4+txLen]
+			l2Txs = append(l2Txs, txData)
+		}
+
+		chunks = append(chunks, &Chunk{
+			BlockContexts: blockContexts,
+			L2Txs:         l2Txs,
+		})
+	}
+	return chunks, nil
+}
+
+func countTotalL1MessagePopped(chunks Chunks) uint64 {
+	var total uint64 = 0
+	for _, chunk := range chunks {
+		for _, block := range chunk.BlockContexts {
+			total += uint64(block.NumL1Messages)
+		}
+	}
+	return total
+}