+package protocol
+
+import (
+ "encoding/hex"
+ "fmt"
+
+ log "github.com/sirupsen/logrus"
+
+ "github.com/vapor/config"
+ "github.com/vapor/errors"
+ "github.com/vapor/event"
+ "github.com/vapor/protocol/bc"
+ "github.com/vapor/protocol/bc/types"
+ "github.com/vapor/protocol/state"
+)
+
+const (
+ maxSignatureCacheSize = 10000
+)
+
+var (
+ errVotingOperationOverFlow = errors.New("voting operation result overflow")
+ errDoubleSignBlock = errors.New("the consensus is double sign in same height of different block")
+ errInvalidSignature = errors.New("the signature of block is invalid")
+ errSignForkChain = errors.New("can not sign fork before the irreversible block")
+)
+
+func signCacheKey(blockHash, pubkey string) string {
+ return fmt.Sprintf("%s:%s", blockHash, pubkey)
+}
+
+func (c *Chain) isIrreversible(blockNode *state.BlockNode) bool {
+ consensusNodes, err := c.consensusNodeManager.getConsensusNodes(&blockNode.Parent.Hash)
+ if err != nil {
+ return false
+ }
+
+ signCount := 0
+ for i := 0; i < len(consensusNodes); i++ {
+ if ok, _ := blockNode.BlockWitness.Test(uint32(i)); ok {
+ signCount++
+ }
+ }
+
+ return signCount > len(consensusNodes)*2/3
+}
+
+// GetVoteResultByHash return vote result by block hash
+func (c *Chain) GetVoteResultByHash(blockHash *bc.Hash) (*state.VoteResult, error) {
+ blockNode := c.index.GetNode(blockHash)
+ return c.consensusNodeManager.getVoteResult(state.CalcVoteSeq(blockNode.Height), blockNode)
+}
+
+// IsBlocker returns whether the consensus node is a blocker at the specified time
+func (c *Chain) IsBlocker(prevBlockHash *bc.Hash, pubKey string, timeStamp uint64) (bool, error) {
+ xPub, err := c.consensusNodeManager.getBlocker(prevBlockHash, timeStamp)
+ if err != nil {
+ return false, err
+ }
+ return xPub == pubKey, nil
+}
+
+// GetBlock return blocker by specified timestamp
+func (c *Chain) GetBlocker(prevBlockHash *bc.Hash, timestamp uint64) (string, error) {
+ return c.consensusNodeManager.getBlocker(prevBlockHash, timestamp)
+}
+
+// ProcessBlockSignature process the received block signature messages
+// return whether a block become irreversible, if so, the chain module must update status
+func (c *Chain) ProcessBlockSignature(signature, xPub []byte, blockHash *bc.Hash) error {
+ xpubStr := hex.EncodeToString(xPub[:])
+ blockNode := c.index.GetNode(blockHash)
+ // save the signature if the block is not exist
+ if blockNode == nil {
+ cacheKey := signCacheKey(blockHash.String(), xpubStr)
+ c.signatureCache.Add(cacheKey, signature)
+ return nil
+ }
+
+ consensusNode, err := c.consensusNodeManager.getConsensusNode(&blockNode.Parent.Hash, xpubStr)
+ if err != nil {
+ return err
+ }
+
+ if exist, _ := blockNode.BlockWitness.Test(uint32(consensusNode.Order)); exist {
+ return nil
+ }
+
+ c.cond.L.Lock()
+ defer c.cond.L.Unlock()
+ if err := c.checkNodeSign(blockNode.BlockHeader(), consensusNode, signature); err != nil {
+ return err
+ }
+
+ if err := c.updateBlockSignature(blockNode, consensusNode.Order, signature); err != nil {
+ return err
+ }
+ return c.eventDispatcher.Post(event.BlockSignatureEvent{BlockHash: *blockHash, Signature: signature, XPub: xPub})
+}
+
+// validateSign verify the signatures of block, and return the number of correct signature
+// if some signature is invalid, they will be reset to nil
+// if the block has not the signature of blocker, it will return error
+func (c *Chain) validateSign(block *types.Block) error {
+ consensusNodeMap, err := c.consensusNodeManager.getConsensusNodes(&block.PreviousBlockHash)
+ if err != nil {
+ return err
+ }
+
+ hasBlockerSign := false
+ blockHash := block.Hash()
+ for pubKey, node := range consensusNodeMap {
+ if len(block.Witness) <= int(node.Order) {
+ continue
+ }
+
+ if block.Get(node.Order) == nil {
+ cachekey := signCacheKey(blockHash.String(), pubKey)
+ if signature, ok := c.signatureCache.Get(cachekey); ok {
+ block.Set(node.Order, signature.([]byte))
+ } else {
+ continue
+ }
+ }
+
+ if err := c.checkNodeSign(&block.BlockHeader, node, block.Get(node.Order)); err == errDoubleSignBlock {
+ log.WithFields(log.Fields{"module": logModule, "blockHash": blockHash.String(), "pubKey": pubKey}).Warn("the consensus node double sign the same height of different block")
+ block.Delete(node.Order)
+ continue
+ } else if err != nil {
+ return err
+ }
+
+ isBlocker, err := c.IsBlocker(&block.PreviousBlockHash, pubKey, block.Timestamp)
+ if err != nil {
+ return err
+ }
+
+ if isBlocker {
+ hasBlockerSign = true
+ }
+
+ }
+
+ if !hasBlockerSign {
+ return errors.New("the block has no signature of the blocker")
+ }
+ return nil
+}
+
+func (c *Chain) checkNodeSign(bh *types.BlockHeader, consensusNode *state.ConsensusNode, signature []byte) error {
+ if !consensusNode.XPub.Verify(bh.Hash().Bytes(), signature) {
+ return errInvalidSignature
+ }
+
+ blockNodes := c.consensusNodeManager.blockIndex.NodesByHeight(bh.Height)
+ for _, blockNode := range blockNodes {
+ if blockNode.Hash == bh.Hash() {
+ continue
+ }
+
+ consensusNode, err := c.consensusNodeManager.getConsensusNode(&blockNode.Parent.Hash, consensusNode.XPub.String())
+ if err != nil && err != errNotFoundConsensusNode {
+ return err
+ }
+
+ if err == errNotFoundConsensusNode {
+ continue
+ }
+
+ if ok, err := blockNode.BlockWitness.Test(uint32(consensusNode.Order)); err == nil && ok {
+ return errDoubleSignBlock
+ }
+ }
+ return nil
+}
+
+// SignBlock signing the block if current node is consensus node
+func (c *Chain) SignBlock(block *types.Block) ([]byte, error) {
+ xprv := config.CommonConfig.PrivateKey()
+ xpubStr := xprv.XPub().String()
+ node, err := c.consensusNodeManager.getConsensusNode(&block.PreviousBlockHash, xpubStr)
+ if err == errNotFoundConsensusNode {
+ return nil, nil
+ } else if err != nil {
+ return nil, err
+ }
+
+ c.cond.L.Lock()
+ defer c.cond.L.Unlock()
+ //check double sign in same block height
+ blockNodes := c.consensusNodeManager.blockIndex.NodesByHeight(block.Height)
+ for _, blockNode := range blockNodes {
+ // Has already signed the same height block
+ if ok, err := blockNode.BlockWitness.Test(uint32(node.Order)); err == nil && ok {
+ return nil, nil
+ }
+ }
+
+ for blockNode := c.index.GetNode(&block.PreviousBlockHash); !c.index.InMainchain(blockNode.Hash); blockNode = blockNode.Parent {
+ if blockNode.Height <= c.bestIrreversibleNode.Height {
+ return nil, errSignForkChain
+ }
+ }
+
+ signature := block.Get(node.Order)
+ if len(signature) == 0 {
+ signature = xprv.Sign(block.Hash().Bytes())
+ block.Set(node.Order, signature)
+ }
+ return signature, nil
+}
+
+func (c *Chain) updateBlockSignature(blockNode *state.BlockNode, nodeOrder uint64, signature []byte) error {
+ if err := blockNode.BlockWitness.Set(uint32(nodeOrder)); err != nil {
+ return err
+ }
+
+ blockHeader, err := c.store.GetBlockHeader(&blockNode.Hash, blockNode.Height)
+ if err != nil {
+ return err
+ }
+
+ blockHeader.Set(nodeOrder, signature)
+
+ if err := c.store.SaveBlockHeader(blockHeader); err != nil {
+ return err
+ }
+
+ if c.isIrreversible(blockNode) && blockNode.Height > c.bestIrreversibleNode.Height {
+ if err := c.store.SaveChainStatus(c.bestNode, blockNode, state.NewUtxoViewpoint(), []*state.VoteResult{}); err != nil {
+ return err
+ }
+
+ c.bestIrreversibleNode = blockNode
+ }
+ return nil
+}