Merge pull request #52 from maticnetwork/dev-roothash

new: Add bor.getRootHash(start, end) api method (MAT-1302)

consensus/bor/api.go

@@ -17,10 +17,24 @@
 package bor
 
 import (
+	"math"
+	"math/big"
+	"strconv"
+	"sync"
+
+	lru "github.com/hashicorp/golang-lru"
 	"github.com/maticnetwork/bor/common"
 	"github.com/maticnetwork/bor/consensus"
 	"github.com/maticnetwork/bor/core/types"
+	"github.com/maticnetwork/bor/crypto"
 	"github.com/maticnetwork/bor/rpc"
+	"github.com/xsleonard/go-merkle"
+	"golang.org/x/crypto/sha3"
+)
+
+var (
+	// MaxCheckpointLength is the maximum number of blocks that can be requested for constructing a checkpoint root hash
+	MaxCheckpointLength = uint64(math.Pow(2, 15))
 )
 
 // API is a user facing RPC API to allow controlling the signer and voting
@@ -28,6 +42,7 @@ import (
 type API struct {
 	chain         consensus.ChainReader
 	bor           *Bor
+	rootHashCache *lru.ARCCache
 }
 
 // GetSnapshot retrieves the state snapshot at a given block.
@@ -105,3 +120,71 @@ func (api *API) GetCurrentValidators() ([]*Validator, error) {
 	}
 	return snap.ValidatorSet.Validators, nil
 }
+
+// GetRootHash returns the merkle root of the start to end block headers
+func (api *API) GetRootHash(start int64, end int64) ([]byte, error) {
+	if err := api.initializeRootHashCache(); err != nil {
+		return nil, err
+	}
+	key := getRootHashKey(start, end)
+	if root, known := api.rootHashCache.Get(key); known {
+		return root.([]byte), nil
+	}
+	length := uint64(end - start + 1)
+	if length > MaxCheckpointLength {
+		return nil, &MaxCheckpointLengthExceededError{start, end}
+	}
+	currentHeaderNumber := api.chain.CurrentHeader().Number.Int64()
+	if start > end || end > currentHeaderNumber {
+		return nil, &InvalidStartEndBlockError{start, end, currentHeaderNumber}
+	}
+	blockHeaders := make([]*types.Header, end-start+1)
+	wg := new(sync.WaitGroup)
+	concurrent := make(chan bool, 20)
+	for i := start; i <= end; i++ {
+		wg.Add(1)
+		concurrent <- true
+		go func(number int64) {
+			blockHeaders[number-start] = api.chain.GetHeaderByNumber(uint64(number))
+			<-concurrent
+			wg.Done()
+		}(i)
+	}
+	wg.Wait()
+	close(concurrent)
+
+	headers := make([][32]byte, nextPowerOfTwo(length))
+	for i := 0; i < len(blockHeaders); i++ {
+		blockHeader := blockHeaders[i]
+		header := crypto.Keccak256(appendBytes32(
+			blockHeader.Number.Bytes(),
+			new(big.Int).SetUint64(blockHeader.Time).Bytes(),
+			blockHeader.TxHash.Bytes(),
+			blockHeader.ReceiptHash.Bytes(),
+		))
+
+		var arr [32]byte
+		copy(arr[:], header)
+		headers[i] = arr
+	}
+
+	tree := merkle.NewTreeWithOpts(merkle.TreeOptions{EnableHashSorting: false, DisableHashLeaves: true})
+	if err := tree.Generate(convert(headers), sha3.NewLegacyKeccak256()); err != nil {
+		return nil, err
+	}
+	root := tree.Root().Hash
+	api.rootHashCache.Add(key, root)
+	return root, nil
+}
+
+func (api *API) initializeRootHashCache() error {
+	var err error
+	if api.rootHashCache == nil {
+		api.rootHashCache, err = lru.NewARC(10)
+	}
+	return err
+}
+
+func getRootHashKey(start int64, end int64) string {
+	return strconv.FormatInt(start, 10) + "-" + strconv.FormatInt(end, 10)
+}

consensus/bor/errors.go

@@ -40,3 +40,31 @@ func (e *TotalVotingPowerExceededError) Error() string {
 		e.Validators,
 	)
 }
+
+type InvalidStartEndBlockError struct {
+	Start         int64
+	End           int64
+	CurrentHeader int64
+}
+
+func (e *InvalidStartEndBlockError) Error() string {
+	return fmt.Sprintf(
+		"Invalid parameters start: %d and end block: %d params",
+		e.Start,
+		e.End,
+	)
+}
+
+type MaxCheckpointLengthExceededError struct {
+	Start int64
+	End   int64
+}
+
+func (e *MaxCheckpointLengthExceededError) Error() string {
+	return fmt.Sprintf(
+		"Start: %d and end block: %d exceed max allowed checkpoint length: %d",
+		e.Start,
+		e.End,
+		MaxCheckpointLength,
+	)
+}

consensus/bor/merkle.go

+package bor
+
+func appendBytes32(data ...[]byte) []byte {
+	var result []byte
+	for _, v := range data {
+		paddedV, err := convertTo32(v)
+		if err == nil {
+			result = append(result, paddedV[:]...)
+		}
+	}
+	return result
+}
+
+func nextPowerOfTwo(n uint64) uint64 {
+	if n == 0 {
+		return 1
+	}
+	// http://graphics.stanford.edu/~seander/bithacks.html#RoundUpPowerOf2
+	n--
+	n |= n >> 1
+	n |= n >> 2
+	n |= n >> 4
+	n |= n >> 8
+	n |= n >> 16
+	n |= n >> 32
+	n++
+	return n
+}
+
+func convertTo32(input []byte) (output [32]byte, err error) {
+	l := len(input)
+	if l > 32 || l == 0 {
+		return
+	}
+	copy(output[32-l:], input[:])
+	return
+}
+
+func convert(input []([32]byte)) [][]byte {
+	var output [][]byte
+	for _, in := range input {
+		newInput := make([]byte, len(in[:]))
+		copy(newInput, in[:])
+		output = append(output, newInput)
+
+	}
+	return output
+}

eth/api_backend.go

@@ -248,3 +248,17 @@ func (b *EthAPIBackend) ServiceFilter(ctx context.Context, session *bloombits.Ma
 		go session.Multiplex(bloomRetrievalBatch, bloomRetrievalWait, b.eth.bloomRequests)
 	}
 }
+
+func (b *EthAPIBackend) GetRootHash(ctx context.Context, starBlockNr rpc.BlockNumber, endBlockNr rpc.BlockNumber) ([]byte, error) {
+	var api *bor.API
+	for _, _api := range b.eth.Engine().APIs(b.eth.BlockChain()) {
+		if _api.Namespace == "bor" {
+			api = _api.Service.(*bor.API)
+		}
+	}
+	root, err := api.GetRootHash(starBlockNr.Int64(), endBlockNr.Int64())
+	if err != nil {
+		return nil, err
+	}
+	return root, nil
+}

go.mod

@@ -60,6 +60,7 @@ require (
 	github.com/syndtr/goleveldb v1.0.1-0.20190923125748-758128399b1d
 	github.com/tyler-smith/go-bip39 v1.0.1-0.20181017060643-dbb3b84ba2ef
 	github.com/wsddn/go-ecdh v0.0.0-20161211032359-48726bab9208
+	github.com/xsleonard/go-merkle v1.1.0
 	golang.org/x/crypto v0.0.0-20200311171314-f7b00557c8c4
 	golang.org/x/net v0.0.0-20200301022130-244492dfa37a
 	golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e

go.sum

@@ -176,6 +176,8 @@ github.com/tyler-smith/go-bip39 v1.0.1-0.20181017060643-dbb3b84ba2ef h1:wHSqTBrZ
 github.com/tyler-smith/go-bip39 v1.0.1-0.20181017060643-dbb3b84ba2ef/go.mod h1:sJ5fKU0s6JVwZjjcUEX2zFOnvq0ASQ2K9Zr6cf67kNs=
 github.com/wsddn/go-ecdh v0.0.0-20161211032359-48726bab9208 h1:1cngl9mPEoITZG8s8cVcUy5CeIBYhEESkOB7m6Gmkrk=
 github.com/wsddn/go-ecdh v0.0.0-20161211032359-48726bab9208/go.mod h1:IotVbo4F+mw0EzQ08zFqg7pK3FebNXpaMsRy2RT+Ees=
+github.com/xsleonard/go-merkle v1.1.0 h1:fHe1fuhJjGH22ZzVTAH0jqHLhTGhOq3wQjJN+8P0jQg=
+github.com/xsleonard/go-merkle v1.1.0/go.mod h1:cW4z+UZ/4f2n9IJgIiyDCdYguchoDyDAPmpuOWGxdGg=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2 h1:VklqNMn3ovrHsnt90PveolxSbWFaJdECFbxSq0Mqo2M=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20200311171314-f7b00557c8c4 h1:QmwruyY+bKbDDL0BaglrbZABEali68eoMFhTZpCjYVA=

internal/ethapi/api.go

@@ -716,6 +716,14 @@ func (s *PublicBlockChainAPI) GetStorageAt(ctx context.Context, address common.A
 	return res[:], state.Error()
 }
 
+func (s *PublicBlockChainAPI) GetRootHash(ctx context.Context, starBlockNr rpc.BlockNumber, endBlockNr rpc.BlockNumber) ([]byte, error) {
+	root, err := s.b.GetRootHash(ctx, starBlockNr, endBlockNr)
+	if err != nil {
+		return nil, err
+	}
+	return root, nil
+}
+
 // CallArgs represents the arguments for a call.
 type CallArgs struct {
 	From     *common.Address `json:"from"`

internal/ethapi/backend.go

@@ -62,6 +62,7 @@ type Backend interface {
 	SubscribeStateEvent(ch chan<- core.NewStateChangeEvent) event.Subscription
 	SubscribeChainHeadEvent(ch chan<- core.ChainHeadEvent) event.Subscription
 	SubscribeChainSideEvent(ch chan<- core.ChainSideEvent) event.Subscription
+	GetRootHash(ctx context.Context, starBlockNr rpc.BlockNumber, endBlockNr rpc.BlockNumber) ([]byte, error)
 
 	// Transaction pool API
 	SendTx(ctx context.Context, signedTx *types.Transaction) error

internal/web3ext/web3ext.go

@@ -149,6 +149,11 @@ web3._extend({
 			call: 'bor_getCurrentValidators',
 			params: 0
 		}),
+		new web3._extend.Method({
+			name: 'getRootHash',
+			call: 'bor_getRootHash',
+			params: 2,
+		}),
 	]
 });
 `

les/api_backend.go

@@ -223,3 +223,7 @@ func (b *LesApiBackend) ServiceFilter(ctx context.Context, session *bloombits.Ma
 		go session.Multiplex(bloomRetrievalBatch, bloomRetrievalWait, b.eth.bloomRequests)
 	}
 }
+
+func (b *LesApiBackend) GetRootHash(ctx context.Context, starBlockNr rpc.BlockNumber, endBlockNr rpc.BlockNumber) ([]byte, error) {
+	return nil, errors.New("Not implemented")
+}