add merkle proof generation/validation and cxreceipts message handler function

api/proto/node/node.go

@@ -35,6 +35,12 @@ type BlockchainSyncMessage struct {
 	BlockHashes []common.Hash
 }
 
+// CXReceiptsMessage carrys the cross shard receipts and merkle proof
+type CXReceiptsMessage struct {
+	CXS types.CXReceipts
+	MKP *types.CXMerkleProof
+}
+
 // BlockchainSyncMessageType represents BlockchainSyncMessageType type.
 type BlockchainSyncMessageType int
 
@@ -188,3 +194,20 @@ func DeserializeEpochShardStateFromMessage(payload []byte) (*types.EpochShardSta
 
 	return epochShardState, nil
 }
+
+// ConstructCXReceiptsMessage constructs cross shard receipts and merkle proof
+func ConstructCXReceiptsMessage(cxs types.CXReceipts, mkp *types.CXMerkleProof) []byte {
+	msg := &CXReceiptsMessage{CXS: cxs, MKP: mkp}
+
+	byteBuffer := bytes.NewBuffer([]byte{byte(proto.Node)})
+	byteBuffer.WriteByte(byte(Block))
+	byteBuffer.WriteByte(byte(Receipt))
+	by, err := rlp.EncodeToBytes(msg)
+
+	if err != nil {
+		log.Fatal(err)
+		return []byte{}
+	}
+	byteBuffer.Write(by)
+	return byteBuffer.Bytes()
+}

cmd/client/wallet/main.go

@@ -719,7 +719,7 @@ func processTransferCommand() {
 			gas, nil, inputData)
 	} else {
 		tx = types.NewCrossShardTransaction(
-			state.nonce, receiverAddress, fromShard, toShard, amountBigInt,
+			state.nonce, &receiverAddress, fromShard, toShard, amountBigInt,
 			gas, nil, inputData, types.SubtractionOnly)
 	}
 

core/block_validator.go

@@ -91,7 +91,7 @@ func (v *BlockValidator) ValidateState(block, parent *types.Block, statedb *stat
 		return fmt.Errorf("invalid receipt root hash (remote: %x local: %x)", header.ReceiptHash, receiptSha)
 	}
 
-	cxsSha := types.DeriveSha(cxReceipts)
+	cxsSha := types.DeriveMultipleShardsSha(cxReceipts)
 	if cxsSha != header.CXReceiptHash {
 		return fmt.Errorf("invalid cross shard receipt root hash (remote: %x local: %x)", header.CXReceiptHash, cxsSha)
 	}

core/blockchain.go

@@ -980,7 +980,7 @@ func (bc *BlockChain) WriteBlockWithoutState(block *types.Block, td *big.Int) (e
 }
 
 // WriteBlockWithState writes the block and all associated state to the database.
-func (bc *BlockChain) WriteBlockWithState(block *types.Block, receipts []*types.Receipt, state *state.DB) (status WriteStatus, err error) {
+func (bc *BlockChain) WriteBlockWithState(block *types.Block, receipts []*types.Receipt, cxReceipts []*types.CXReceipt, state *state.DB) (status WriteStatus, err error) {
 	bc.wg.Add(1)
 	defer bc.wg.Done()
 
@@ -1053,6 +1053,17 @@ func (bc *BlockChain) WriteBlockWithState(block *types.Block, receipts []*types.
 	batch := bc.db.NewBatch()
 	rawdb.WriteReceipts(batch, block.Hash(), block.NumberU64(), receipts)
 
+	epoch := block.Header().Epoch
+	shardingConfig := ShardingSchedule.InstanceForEpoch(epoch)
+	shardNum := int(shardingConfig.NumShards())
+	for i := 0; i < shardNum; i++ {
+		if i == int(block.ShardID()) {
+			continue
+		}
+		shardReceipts := GetToShardReceipts(cxReceipts, uint32(i))
+		rawdb.WriteCXReceipts(batch, uint32(i), block.NumberU64(), block.Hash(), shardReceipts)
+	}
+
 	// If the total difficulty is higher than our known, add it to the canonical chain
 	// Second clause in the if statement reduces the vulnerability to selfish mining.
 	// Please refer to http://www.cs.cornell.edu/~ie53/publications/btcProcFC.pdf
@@ -1273,7 +1284,7 @@ func (bc *BlockChain) insertChain(chain types.Blocks) (int, []interface{}, []*ty
 		proctime := time.Since(bstart)
 
 		// Write the block to the chain and get the status.
-		status, err := bc.WriteBlockWithState(block, receipts, state)
+		status, err := bc.WriteBlockWithState(block, receipts, cxReceipts, state)
 		if err != nil {
 			return i, events, coalescedLogs, err
 		}
@@ -2000,3 +2011,52 @@ func (bc *BlockChain) ChainDB() ethdb.Database {
 func (bc *BlockChain) GetVMConfig() *vm.Config {
 	return &bc.vmConfig
 }
+
+// GetToShardReceipts filters the cross shard receipts with given destination shardID
+func GetToShardReceipts(cxReceipts types.CXReceipts, shardID uint32) types.CXReceipts {
+	cxs := types.CXReceipts{}
+	for i := range cxReceipts {
+		cx := cxReceipts[i]
+		if cx.ToShardID == shardID {
+			cxs = append(cxs, cx)
+		}
+	}
+	return cxs
+}
+
+// CXReceipts retrieves the cross shard transaction receipts of a given shard
+func (bc *BlockChain) CXReceipts(shardID uint32, blockNum uint64, blockHash common.Hash) (types.CXReceipts, error) {
+	cxs, err := rawdb.ReadCXReceipts(bc.db, shardID, blockNum, blockHash)
+	if err != nil || len(cxs) == 0 {
+		return nil, err
+	}
+	return cxs, nil
+}
+
+// CXMerkleProof calculates the cross shard transaction merkle proof of a given destination shard
+func (bc *BlockChain) CXMerkleProof(shardID uint32, block *types.Block) (*types.CXMerkleProof, error) {
+	proof := &types.CXMerkleProof{BlockHash: block.Hash(), CXReceiptHash: block.Header().CXReceiptHash, CXShardHash: []common.Hash{}, ShardID: []uint32{}}
+	cxs, err := rawdb.ReadCXReceipts(bc.db, shardID, block.NumberU64(), block.Hash())
+	if err != nil || cxs == nil {
+		return nil, err
+	}
+
+	epoch := block.Header().Epoch
+	shardingConfig := ShardingSchedule.InstanceForEpoch(epoch)
+	shardNum := int(shardingConfig.NumShards())
+
+	for i := 0; i < shardNum; i++ {
+		receipts, err := bc.CXReceipts(uint32(i), block.NumberU64(), block.Hash())
+		if err != nil || len(receipts) == 0 {
+			continue
+		} else {
+			hash := types.DeriveSha(receipts)
+			proof.CXShardHash = append(proof.CXShardHash, hash)
+			proof.ShardID = append(proof.ShardID, uint32(i))
+		}
+	}
+	if len(proof.ShardID) == 0 {
+		return nil, nil
+	}
+	return proof, nil
+}

core/rawdb/accessors_chain.go

@@ -513,31 +513,30 @@ func WriteCrossLinkShardBlock(db DatabaseWriter, shardID uint32, blockNum uint64
 	return db.Put(crosslinkKey(shardID, blockNum), data)
 }
 
-// ReadCXReceipts retrieves all the transaction receipts belonging to a block.
-func ReadCXReceipts(db DatabaseReader, shardID uint32, number uint64, hash common.Hash) types.CXReceipts {
-	// Retrieve the flattened receipt slice
-	data, _ := db.Get(cxReceiptKey(shardID, number, hash))
-	if len(data) == 0 {
-		return nil
+// ReadCXReceipts retrieves all the transactions of receipts given destination shardID, number and blockHash
+func ReadCXReceipts(db DatabaseReader, shardID uint32, number uint64, hash common.Hash) (types.CXReceipts, error) {
+	data, err := db.Get(cxReceiptKey(shardID, number, hash))
+	if len(data) == 0 || err != nil {
+		utils.Logger().Info().Err(err).Uint64("number", number).Int("dataLen", len(data)).Msg("ReadCXReceipts")
+		return nil, err
 	}
-	// Convert the cross shard tx receipts from their storage form to their internal representation
 	cxReceipts := types.CXReceipts{}
 	if err := rlp.DecodeBytes(data, &cxReceipts); err != nil {
 		utils.Logger().Error().Err(err).Str("hash", hash.Hex()).Msg("Invalid cross-shard tx receipt array RLP")
-		return nil
+		return nil, err
 	}
-	return cxReceipts
+	return cxReceipts, nil
 }
 
-// WriteCXReceipts stores all the transaction receipts belonging to a block.
+// WriteCXReceipts stores all the transaction receipts given destination shardID, blockNumber and blockHash
 func WriteCXReceipts(db DatabaseWriter, shardID uint32, number uint64, hash common.Hash, receipts types.CXReceipts) {
 	bytes, err := rlp.EncodeToBytes(receipts)
 	if err != nil {
-		utils.Logger().Error().Msg("Failed to encode cross shard tx receipts")
+		utils.Logger().Error().Msg("[WriteCXReceipts] Failed to encode cross shard tx receipts")
 	}
 	// Store the receipt slice
 	if err := db.Put(cxReceiptKey(shardID, number, hash), bytes); err != nil {
-		utils.Logger().Error().Msg("Failed to store block receipts")
+		utils.Logger().Error().Msg("[WriteCXReceipts] Failed to store cxreceipts")
 	}
 }
 

core/rawdb/schema.go

@@ -62,7 +62,8 @@ var (
 
 	crosslinkPrefix = []byte("crosslink") // prefix for crosslink
 
-	cxReceiptPrefix = []byte("cxReceipt") // prefix for cross shard transaction receipt
+	cxReceiptPrefix     = []byte("cxReceipt")     // prefix for cross shard transaction receipt
+	cxReceiptHashPrefix = []byte("cxReceiptHash") // prefix for cross shard transaction receipt hash
 
 	// epochBlockNumberPrefix + epoch (big.Int.Bytes())
 	// -> epoch block number (big.Int.Bytes())

core/state_processor.go

@@ -124,7 +124,7 @@ func ApplyTransaction(config *params.ChainConfig, bc ChainContext, author *commo
 	//receipt.Logs = statedb.GetLogs(tx.Hash())
 	receipt.Bloom = types.CreateBloom(types.Receipts{receipt})
 
-	cxReceipt := &types.CXReceipt{tx.Hash(), msg.Nonce(), msg.From(), *msg.To(), tx.ShardID(), tx.ToShardID(), msg.Value()}
+	cxReceipt := &types.CXReceipt{tx.Hash(), msg.Nonce(), msg.From(), msg.To(), tx.ShardID(), tx.ToShardID(), msg.Value()}
 
 	return receipt, cxReceipt, gas, err
 }

core/types/block.go

@@ -245,11 +245,7 @@ func NewBlock(header *Header, txs []*Transaction, receipts []*Receipt, cxs []*CX
 		b.header.Bloom = CreateBloom(receipts)
 	}
 
-	if len(cxs) == 0 {
-		b.header.CXReceiptHash = EmptyRootHash
-	} else {
-		b.header.CXReceiptHash = DeriveSha(CXReceipts(cxs))
-	}
+	b.header.CXReceiptHash = DeriveMultipleShardsSha(CXReceipts(cxs))
 
 	return b
 }

core/types/cx_receipt.go

@@ -12,7 +12,7 @@ type CXReceipt struct {
 	TxHash    common.Hash // hash of the cross shard transaction in source shard
 	Nonce     uint64
 	From      common.Address
-	To        common.Address
+	To        *common.Address
 	ShardID   uint32
 	ToShardID uint32
 	Amount    *big.Int
@@ -33,12 +33,31 @@ func (cs CXReceipts) GetRlp(i int) []byte {
 	return enc
 }
 
-// ShardID returns the destination shardID of the cxReceipt
+// ToShardID returns the destination shardID of the cxReceipt
 func (cs CXReceipts) ToShardID(i int) uint32 {
 	return cs[i].ToShardID
 }
 
+// MaxToShardID returns the maximum destination shardID of cxReceipts
+func (cs CXReceipts) MaxToShardID() uint32 {
+	maxShardID := uint32(0)
+	for i := 0; i < len(cs); i++ {
+		if maxShardID < cs[i].ToShardID {
+			maxShardID = cs[i].ToShardID
+		}
+	}
+	return maxShardID
+}
+
 // NewCrossShardReceipt creates a cross shard receipt
-func NewCrossShardReceipt(txHash common.Hash, nonce uint64, from common.Address, to common.Address, shardID uint32, toShardID uint32, amount *big.Int) *CXReceipt {
+func NewCrossShardReceipt(txHash common.Hash, nonce uint64, from common.Address, to *common.Address, shardID uint32, toShardID uint32, amount *big.Int) *CXReceipt {
 	return &CXReceipt{TxHash: txHash, Nonce: nonce, From: from, To: to, ShardID: shardID, ToShardID: toShardID, Amount: amount}
 }
+
+// CXMerkleProof represents the merkle proof of a collection of ordered cross shard transactions
+type CXMerkleProof struct {
+	BlockHash     common.Hash   // block header's hash
+	CXReceiptHash common.Hash   // root hash of the cross shard receipts in a given block
+	ShardID       []uint32      // order list, records destination shardID
+	CXShardHash   []common.Hash // ordered hash list, each hash corresponds to one destination shard's receipts root hash
+}

core/types/derive_sha.go

@@ -18,6 +18,7 @@ package types
 
 import (
 	"bytes"
+	"encoding/binary"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/crypto"
@@ -30,6 +31,7 @@ type DerivableList interface {
 	Len() int
 	GetRlp(i int) []byte
 	ToShardID(i int) uint32
+	MaxToShardID() uint32 // return the maximum non-empty destination shardID
 }
 
 // DeriveSha calculates the hash of the trie generated by DerivableList.
@@ -60,12 +62,23 @@ func DeriveOneShardSha(list DerivableList, shardID uint32) common.Hash {
 	return trie.Hash()
 }
 
-// DeriveMultipleShardsSha calcualtes the hash of tries generated by DerivableList of multiple shards
-func DeriveMultipleShardsSha(list DerivableList, numShards int) common.Hash {
+// DeriveMultipleShardsSha calcualtes the root hash of tries generated by DerivableList of multiple shards
+// If the list is empty, then return EmptyRootHash
+// else, return |shard0|trieHash0|shard1|trieHash1|...| for non-empty destination shards
+func DeriveMultipleShardsSha(list DerivableList) common.Hash {
 	by := []byte{}
-	for i := 0; i < numShards; i++ {
+	for i := 0; i <= int(list.MaxToShardID()); i++ {
 		shardHash := DeriveOneShardSha(list, uint32(i))
+		if shardHash == EmptyRootHash {
+			continue
+		}
+		sKey := make([]byte, 4)
+		binary.BigEndian.PutUint32(sKey, uint32(i))
+		by = append(by, sKey...)
 		by = append(by, shardHash[:]...)
 	}
+	if len(by) == 0 {
+		return EmptyRootHash
+	}
 	return crypto.Keccak256Hash(by)
 }

core/types/receipt.go

@@ -208,9 +208,13 @@ func (r Receipts) GetRlp(i int) []byte {
 	return bytes
 }
 
-// ShardID returns 0, arbitrary value
+// ToShardID returns 0, arbitrary value
 // This function is NOT used, just to compatible with DerivableList interface
 func (r Receipts) ToShardID(i int) uint32 {
-	_ = r[i]
+	return 0
+}
+
+// MaxToShardID returns 0, arbitrary value, NOT used
+func (r Receipts) MaxToShardID() uint32 {
 	return 0
 }

core/types/transaction.go

@@ -106,8 +106,8 @@ func NewTransaction(nonce uint64, to common.Address, shardID uint32, amount *big
 }
 
 // NewCrossShardTransaction returns new cross shard transaction
-func NewCrossShardTransaction(nonce uint64, to common.Address, shardID uint32, toShardID uint32, amount *big.Int, gasLimit uint64, gasPrice *big.Int, data []byte, txType TransactionType) *Transaction {
-	return newCrossShardTransaction(nonce, &to, shardID, toShardID, amount, gasLimit, gasPrice, data, txType)
+func NewCrossShardTransaction(nonce uint64, to *common.Address, shardID uint32, toShardID uint32, amount *big.Int, gasLimit uint64, gasPrice *big.Int, data []byte, txType TransactionType) *Transaction {
+	return newCrossShardTransaction(nonce, to, shardID, toShardID, amount, gasLimit, gasPrice, data, txType)
 }
 
 // NewContractCreation returns same shard contract transaction.
@@ -378,11 +378,16 @@ func (s Transactions) GetRlp(i int) []byte {
 	return enc
 }
 
-// ShardID returns the destination shardID of given transaction
+// ToShardID returns the destination shardID of given transaction
 func (s Transactions) ToShardID(i int) uint32 {
 	return s[i].data.ToShardID
 }
 
+// MaxToShardID returns 0, arbitrary value, NOT use
+func (s Transactions) MaxToShardID() uint32 {
+	return 0
+}
+
 // TxDifference returns a new set which is the difference between a and b.
 func TxDifference(a, b Transactions) Transactions {
 	keep := make(Transactions, 0, len(a))

node/node_cross_shard.go

@@ -1,8 +1,15 @@
 package node
 
 import (
+	"bytes"
+	"encoding/base64"
+	"encoding/binary"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/rlp"
 
+	proto_node "github.com/harmony-one/harmony/api/proto/node"
 	"github.com/harmony-one/harmony/core/types"
 	"github.com/harmony-one/harmony/internal/utils"
 )
@@ -22,7 +29,56 @@ func (node *Node) ProcessHeaderMessage(msgPayload []byte) {
 
 // ProcessReceiptMessage store the receipts and merkle proof in local data store
 func (node *Node) ProcessReceiptMessage(msgPayload []byte) {
-	// TODO: add logic
+	cxmsg := proto_node.CXReceiptsMessage{}
+	if err := rlp.DecodeBytes(msgPayload, &cxmsg); err != nil {
+		utils.Logger().Error().Err(err).Msg("[ProcessReceiptMessage] Unable to Decode message Payload")
+		return
+	}
+	merkleProof := cxmsg.MKP
+	myShardRoot := common.Hash{}
+
+	var foundMyShard bool
+	byteBuffer := bytes.NewBuffer([]byte{})
+	if len(merkleProof.ShardID) == 0 {
+		utils.Logger().Warn().Msg("[ProcessReceiptMessage] There is No non-empty destination shards")
+		return
+	} else {
+		for j := 0; j < len(merkleProof.ShardID); j++ {
+			sKey := make([]byte, 4)
+			binary.BigEndian.PutUint32(sKey, merkleProof.ShardID[j])
+			byteBuffer.Write(sKey)
+			byteBuffer.Write(merkleProof.CXShardHash[j][:])
+			if merkleProof.ShardID[j] == node.Consensus.ShardID {
+				foundMyShard = true
+				myShardRoot = merkleProof.CXShardHash[j]
+			}
+		}
+	}
+
+	if !foundMyShard {
+		utils.Logger().Warn().Msg("[ProcessReceiptMessage] Not Found My Shard in CXReceipt Message")
+		return
+	}
+
+	hash := crypto.Keccak256Hash(byteBuffer.Bytes())
+	utils.Logger().Debug().Interface("hash", hash).Msg("[ProcessReceiptMessage] RootHash of the CXReceipts")
+	// TODO chao: use crosslink from beacon sync to verify the hash
+
+	cxReceipts := cxmsg.CXS
+	sha := types.DeriveSha(cxReceipts)
+	if sha != myShardRoot {
+		utils.Logger().Warn().Interface("calculated", sha).Interface("got", myShardRoot).Msg("[ProcessReceiptMessage] Trie Root of CXReceipts Not Match")
+		return
+	}
+
+	txs := types.Transactions{}
+	inputData, _ := base64.StdEncoding.DecodeString("")
+	for _, cx := range cxReceipts {
+		// TODO chao: add gas fee to incentivize
+		tx := types.NewCrossShardTransaction(0, cx.To, cx.ShardID, cx.ToShardID, cx.Amount, 0, nil, inputData, types.AdditionOnly)
+		txs = append(txs, tx)
+	}
+	node.addPendingTransactions(txs)
 }
 
 // ProcessCrossShardTx verify and process cross shard transaction on destination shard

node/node_handler.go

@@ -285,6 +285,37 @@ func (node *Node) BroadcastNewBlock(newBlock *types.Block) {
 	}
 }
 
+// BroadcastCXReceipts broadcasts cross shard receipts to correspoding
+// destination shards
+func (node *Node) BroadcastCXReceipts(newBlock *types.Block) {
+	epoch := newBlock.Header().Epoch
+	shardingConfig := core.ShardingSchedule.InstanceForEpoch(epoch)
+	shardNum := int(shardingConfig.NumShards())
+	myShardID := node.Consensus.ShardID
+	utils.Logger().Info().Int("shardNum", shardNum).Uint32("myShardID", myShardID).Uint64("blockNum", newBlock.NumberU64()).Msg("[BroadcastCXReceipts]")
+
+	for i := 0; i < shardNum; i++ {
+		if i == int(myShardID) {
+			continue
+		}
+		cxReceipts, err := node.Blockchain().CXReceipts(uint32(i), newBlock.NumberU64(), newBlock.Hash())
+		if err != nil || len(cxReceipts) == 0 {
+			//utils.Logger().Warn().Err(err).Uint32("ToShardID", uint32(i)).Int("numCXReceipts", len(cxReceipts)).Msg("[BroadcastCXReceipts] No CXReceipts found")
+			continue
+		}
+		merkleProof, err := node.Blockchain().CXMerkleProof(uint32(i), newBlock)
+		if err != nil {
+			utils.Logger().Warn().Uint32("ToShardID", uint32(i)).Msg("[BroadcastCXReceipts] Unable to get merkleProof")
+			continue
+		}
+		utils.Logger().Info().Uint32("ToShardID", uint32(i)).Msg("[BroadcastCXReceipts] CXReceipts and MerkleProof Found")
+
+		groupID := p2p.ShardID(i)
+		go node.host.SendMessageToGroups([]p2p.GroupID{p2p.NewGroupIDByShardID(groupID)}, host.ConstructP2pMessage(byte(0), proto_node.ConstructCXReceiptsMessage(cxReceipts, merkleProof)))
+	}
+
+}
+
 // VerifyNewBlock is called by consensus participants to verify the block (account model) they are running consensus on
 func (node *Node) VerifyNewBlock(newBlock *types.Block) error {
 	// TODO ek – where do we verify parent-child invariants,
@@ -423,21 +454,24 @@ func (node *Node) validateNewShardState(block *types.Block, stakeInfo *map[commo
 // PostConsensusProcessing is called by consensus participants, after consensus is done, to:
 // 1. add the new block to blockchain
 // 2. [leader] send new block to the client
+// 3. [leader] send cross shard tx receipts to destination shard
 func (node *Node) PostConsensusProcessing(newBlock *types.Block) {
+	if err := node.AddNewBlock(newBlock); err != nil {
+		utils.Logger().Error().
+			Err(err).
+			Msg("Error when adding new block")
+		return
+	}
+
 	if node.Consensus.PubKey.IsEqual(node.Consensus.LeaderPubKey) {
 		node.BroadcastNewBlock(newBlock)
+		node.BroadcastCXReceipts(newBlock)
 	} else {
 		utils.Logger().Info().
 			Uint64("ViewID", node.Consensus.GetViewID()).
 			Msg("BINGO !!! Reached Consensus")
 	}
 
-	if err := node.AddNewBlock(newBlock); err != nil {
-		utils.Logger().Error().
-			Err(err).
-			Msg("Error when adding new block")
-	}
-
 	if node.NodeConfig.GetNetworkType() != nodeconfig.Mainnet {
 		// Update contract deployer's nonce so default contract like faucet can issue transaction with current nonce
 		nonce := node.GetNonceOfAddress(crypto.PubkeyToAddress(node.ContractDeployerKey.PublicKey))