The core protocol of WoopChain
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woop/consensus/consensus_leader.go

321 lines
9.6 KiB

package consensus
import (
"bytes"
"crypto/sha256"
"encoding/binary"
"encoding/gob"
"harmony-benchmark/blockchain"
"harmony-benchmark/p2p"
"strings"
"time"
)
// WaitForNewBlock waits for a new block.
func (consensus *Consensus) WaitForNewBlock(blockChannel chan blockchain.Block) {
consensus.Log.Debug("Waiting for block", "consensus", consensus)
for { // keep waiting for new blocks
newBlock := <-blockChannel
// TODO: think about potential race condition
consensus.Log.Debug("STARTING CONSENSUS", "consensus", consensus)
for consensus.state == FINISHED {
time.Sleep(500 * time.Millisecond)
consensus.startConsensus(&newBlock)
break
}
}
}
// ProcessMessageLeader is the leader's consensus message dispatcher
func (consensus *Consensus) ProcessMessageLeader(message []byte) {
msgType, err := GetConsensusMessageType(message)
if err != nil {
consensus.Log.Error("Failed to get consensus message type.", "err", err, "consensus", consensus)
}
payload, err := GetConsensusMessagePayload(message)
if err != nil {
consensus.Log.Error("Failed to get consensus message payload.", "err", err, "consensus", consensus)
}
switch msgType {
case ANNOUNCE:
consensus.Log.Error("Unexpected message type", "msgType", msgType, "consensus", consensus)
case COMMIT:
consensus.processCommitMessage(payload)
case CHALLENGE:
consensus.Log.Error("Unexpected message type", "msgType", msgType, "consensus", consensus)
case RESPONSE:
consensus.processResponseMessage(payload)
case START_CONSENSUS:
consensus.processStartConsensusMessage(payload)
default:
consensus.Log.Error("Unexpected message type", "msgType", msgType, "consensus", consensus)
}
}
// Handler for message which triggers consensus process
func (consensus *Consensus) processStartConsensusMessage(payload []byte) {
tx := blockchain.NewCoinbaseTX("x", "y", 0)
consensus.startConsensus(blockchain.NewGenesisBlock(tx, 0))
}
func (consensus *Consensus) startConsensus(newBlock *blockchain.Block) {
// Copy over block hash and block header data
copy(consensus.blockHash[:], newBlock.Hash[:])
// prepare message and broadcast to validators
byteBuffer := bytes.NewBuffer([]byte{})
encoder := gob.NewEncoder(byteBuffer)
encoder.Encode(newBlock)
consensus.blockHeader = byteBuffer.Bytes()
msgToSend := consensus.constructAnnounceMessage()
p2p.BroadcastMessage(consensus.validators, msgToSend)
// Set state to ANNOUNCE_DONE
consensus.state = ANNOUNCE_DONE
}
// Construct the announce message to send to validators
func (consensus *Consensus) constructAnnounceMessage() []byte {
buffer := bytes.NewBuffer([]byte{})
// 4 byte consensus id
fourBytes := make([]byte, 4)
binary.BigEndian.PutUint32(fourBytes, consensus.consensusId)
buffer.Write(fourBytes)
// 32 byte block hash
buffer.Write(consensus.blockHash[:])
// 2 byte leader id
twoBytes := make([]byte, 2)
binary.BigEndian.PutUint16(twoBytes, consensus.nodeId)
buffer.Write(twoBytes)
// n byte of block header
buffer.Write(consensus.blockHeader)
// 4 byte of payload size
sizeOfPayload := uint32(len(consensus.blockHeader))
binary.BigEndian.PutUint32(fourBytes, sizeOfPayload)
buffer.Write(fourBytes)
// 64 byte of signature on previous data
signature := signMessage(buffer.Bytes())
buffer.Write(signature)
return consensus.ConstructConsensusMessage(ANNOUNCE, buffer.Bytes())
}
func signMessage(message []byte) []byte {
// TODO: implement real ECC signature
mockSignature := sha256.Sum256(message)
return append(mockSignature[:], mockSignature[:]...)
}
func (consensus *Consensus) processCommitMessage(payload []byte) {
//#### Read payload data
offset := 0
// 4 byte consensus id
consensusId := binary.BigEndian.Uint32(payload[offset : offset+4])
offset += 4
// 32 byte block hash
blockHash := payload[offset : offset+32]
offset += 32
// 2 byte validator id
validatorId := string(payload[offset : offset+2])
offset += 2
// 33 byte commit
commit := payload[offset : offset+33]
offset += 33
// 64 byte of signature on previous data
signature := payload[offset : offset+64]
offset += 64
//#### END: Read payload data
// TODO: make use of the data. This is just to avoid the unused variable warning
_ = commit
_ = signature
// check consensus Id
if consensusId != consensus.consensusId {
consensus.Log.Warn("Received COMMIT with wrong consensus Id", "myConsensusId", consensus.consensusId, "theirConsensusId", consensusId, "consensus", consensus)
return
}
if bytes.Compare(blockHash, consensus.blockHash[:]) != 0 {
consensus.Log.Warn("Received COMMIT with wrong consensus Id", "myConsensusId", consensus.consensusId, "theirConsensusId", consensusId, "consensus", consensus)
return
}
// proceed only when the message is not received before
consensus.mutex.Lock()
_, ok := consensus.commits[validatorId]
shouldProcess := !ok
if shouldProcess {
consensus.commits[validatorId] = validatorId
//consensus.Log.Debug("Number of commits received", "count", len(consensus.commits))
}
consensus.mutex.Unlock()
if !shouldProcess {
return
}
if len(consensus.commits) >= (2*len(consensus.validators))/3+1 && consensus.state < CHALLENGE_DONE {
consensus.mutex.Lock()
if len(consensus.commits) >= (2*len(consensus.validators))/3+1 && consensus.state < CHALLENGE_DONE {
consensus.Log.Debug("Enough commits received with signatures", "numOfSignatures", len(consensus.commits))
// Broadcast challenge
msgToSend := consensus.constructChallengeMessage()
p2p.BroadcastMessage(consensus.validators, msgToSend)
// Set state to CHALLENGE_DONE
consensus.state = CHALLENGE_DONE
}
consensus.mutex.Unlock()
}
}
// Construct the challenge message to send to validators
func (consensus *Consensus) constructChallengeMessage() []byte {
buffer := bytes.NewBuffer([]byte{})
// 4 byte consensus id
fourBytes := make([]byte, 4)
binary.BigEndian.PutUint32(fourBytes, consensus.consensusId)
buffer.Write(fourBytes)
// 32 byte block hash
buffer.Write(consensus.blockHash[:])
// 2 byte leader id
twoBytes := make([]byte, 2)
binary.BigEndian.PutUint16(twoBytes, consensus.nodeId)
buffer.Write(twoBytes)
// 33 byte aggregated commit
buffer.Write(getAggregatedCommit(consensus.commits))
// 33 byte aggregated key
buffer.Write(getAggregatedKey(consensus.commits))
// 32 byte challenge
buffer.Write(getChallenge())
// 64 byte of signature on previous data
signature := signMessage(buffer.Bytes())
buffer.Write(signature)
return consensus.ConstructConsensusMessage(CHALLENGE, buffer.Bytes())
}
func getAggregatedCommit(commits map[string]string) []byte {
// TODO: implement actual commit aggregation
var commitArray []string
for _, val := range commits {
commitArray = append(commitArray, val)
}
var commit [32]byte
commit = sha256.Sum256([]byte(strings.Join(commitArray, "")))
return append(commit[:], byte(0))
}
func getAggregatedKey(commits map[string]string) []byte {
// TODO: implement actual key aggregation
var commitArray []string
for key := range commits {
commitArray = append(commitArray, key)
}
var commit [32]byte
commit = sha256.Sum256([]byte(strings.Join(commitArray, "")))
return append(commit[:], byte(0))
}
func getChallenge() []byte {
// TODO: implement actual challenge data
return make([]byte, 32)
}
func (consensus *Consensus) processResponseMessage(payload []byte) {
//#### Read payload data
offset := 0
// 4 byte consensus id
consensusId := binary.BigEndian.Uint32(payload[offset : offset+4])
offset += 4
// 32 byte block hash
blockHash := payload[offset : offset+32]
offset += 32
// 2 byte validator id
validatorId := string(payload[offset : offset+2])
offset += 2
// 32 byte response
response := payload[offset : offset+32]
offset += 32
// 64 byte of signature on previous data
signature := payload[offset : offset+64]
offset += 64
//#### END: Read payload data
// TODO: make use of the data. This is just to avoid the unused variable warning
_ = consensusId
_ = blockHash
_ = response
_ = signature
shouldProcess := true
consensus.mutex.Lock()
// check consensus Id
if consensusId != consensus.consensusId {
shouldProcess = false
consensus.Log.Warn("Received RESPONSE with wrong consensus Id", "myConsensusId", consensus.consensusId, "theirConsensusId", consensusId, "consensus", consensus)
}
// proceed only when the message is not received before
_, ok := consensus.responses[validatorId]
shouldProcess = shouldProcess && !ok
if shouldProcess {
consensus.responses[validatorId] = validatorId
}
consensus.mutex.Unlock()
if !shouldProcess {
return
}
//consensus.Log.Debug("RECEIVED RESPONSE", "consensusId", consensusId)
if len(consensus.responses) >= (2*len(consensus.validators))/3+1 && consensus.state != FINISHED {
consensus.mutex.Lock()
if len(consensus.responses) >= (2*len(consensus.validators))/3+1 && consensus.state != FINISHED {
consensus.Log.Debug("Consensus reached with signatures.", "numOfSignatures", len(consensus.responses))
// Reset state to FINISHED, and clear other data.
consensus.ResetState()
consensus.consensusId++
consensus.Log.Debug("HOORAY!!! CONSENSUS REACHED!!!", "consensusId", consensus.consensusId)
// TODO: reconstruct the whole block from header and transactions
// For now, we used the stored whole block already stored in consensus.blockHeader
txDecoder := gob.NewDecoder(bytes.NewReader(consensus.blockHeader))
var blockHeaderObj blockchain.Block
err := txDecoder.Decode(&blockHeaderObj)
if err != nil {
consensus.Log.Debug("failed to construct the new block after consensus")
}
consensus.OnConsensusDone(&blockHeaderObj)
// Send signal to Node so the new block can be added and new round of consensus can be triggered
consensus.ReadySignal <- 1
}
consensus.mutex.Unlock()
}
}