protocol/bbft.go

   1 package protocol
   2
   3 import (
   4         "encoding/hex"
   5         "fmt"
   6
   7         log "github.com/sirupsen/logrus"
   8
   9         "github.com/vapor/config"
  10         "github.com/vapor/errors"
  11         "github.com/vapor/event"
  12         "github.com/vapor/protocol/bc"
  13         "github.com/vapor/protocol/bc/types"
  14         "github.com/vapor/protocol/state"
  15 )
  16
  17 const (
  18         maxSignatureCacheSize = 10000
  19 )
  20
  21 var (
  22         errDoubleSignBlock  = errors.New("the consensus is double sign in same height of different block")
  23         errInvalidSignature = errors.New("the signature of block is invalid")
  24         errSignForkChain    = errors.New("can not sign fork before the irreversible block")
  25 )
  26
  27 func signCacheKey(blockHash, pubkey string) string {
  28         return fmt.Sprintf("%s:%s", blockHash, pubkey)
  29 }
  30
  31 func (c *Chain) checkDoubleSign(bh *types.BlockHeader, xPub string) error {
  32         blockHashes, err := c.store.GetBlockHashesByHeight(bh.Height)
  33         if err != nil {
  34                 return err
  35         }
  36
  37         for _, blockHash := range blockHashes {
  38                 if *blockHash == bh.Hash() {
  39                         continue
  40                 }
  41
  42                 blockHeader, err := c.store.GetBlockHeader(blockHash)
  43                 if err != nil {
  44                         return err
  45                 }
  46
  47                 consensusNode, err := c.getConsensusNode(&blockHeader.PreviousBlockHash, xPub)
  48                 if err == errNotFoundConsensusNode {
  49                         continue
  50                 } else if err != nil {
  51                         return err
  52                 }
  53
  54                 if blockHeader.BlockWitness.Get(consensusNode.Order) != nil {
  55                         return errDoubleSignBlock
  56                 }
  57         }
  58         return nil
  59 }
  60
  61 func (c *Chain) checkNodeSign(bh *types.BlockHeader, consensusNode *state.ConsensusNode, signature []byte) error {
  62         if !consensusNode.XPub.Verify(bh.Hash().Bytes(), signature) {
  63                 return errInvalidSignature
  64         }
  65
  66         return c.checkDoubleSign(bh, consensusNode.XPub.String())
  67 }
  68
  69 func (c *Chain) isIrreversible(blockHeader *types.BlockHeader) bool {
  70         consensusNodes, err := c.getConsensusNodes(&blockHeader.PreviousBlockHash)
  71         if err != nil {
  72                 return false
  73         }
  74
  75         signCount := 0
  76         for i := 0; i < len(consensusNodes); i++ {
  77                 if blockHeader.BlockWitness.Get(uint64(i)) != nil {
  78                         signCount++
  79                 }
  80         }
  81
  82         return signCount > len(consensusNodes)*2/3
  83 }
  84
  85 func (c *Chain) updateBlockSignature(blockHeader *types.BlockHeader, nodeOrder uint64, signature []byte) error {
  86         blockHeader.Set(nodeOrder, signature)
  87         if err := c.store.SaveBlockHeader(blockHeader); err != nil {
  88                 return err
  89         }
  90
  91         if !c.isIrreversible(blockHeader) || blockHeader.Height <= c.lastIrrBlockHeader.Height {
  92                 return nil
  93         }
  94
  95         if c.InMainChain(blockHeader.Hash()) {
  96                 if err := c.store.SaveChainStatus(c.bestBlockHeader, blockHeader, []*types.BlockHeader{}, state.NewUtxoViewpoint(), []*state.ConsensusResult{}); err != nil {
  97                         return err
  98                 }
  99
 100                 c.lastIrrBlockHeader = blockHeader
 101         } else {
 102                 // block is on a forked chain
 103                 log.WithFields(log.Fields{"module": logModule}).Info("majority votes received on forked chain")
 104                 tail, err := c.traceLongestChainTail(blockHeader)
 105                 if err != nil {
 106                         return err
 107                 }
 108
 109                 return c.reorganizeChain(tail)
 110         }
 111         return nil
 112 }
 113
 114 // validateSign verify the signatures of block, and return the number of correct signature
 115 // if some signature is invalid, they will be reset to nil
 116 // if the block does not have the signature of blocker, it will return error
 117 func (c *Chain) validateSign(block *types.Block) error {
 118         consensusNodeMap, err := c.getConsensusNodes(&block.PreviousBlockHash)
 119         if err != nil {
 120                 return err
 121         }
 122
 123         blocker, err := c.GetBlocker(&block.PreviousBlockHash, block.Timestamp)
 124         if err != nil {
 125                 return err
 126         }
 127
 128         hasBlockerSign := false
 129         blockHash := block.Hash()
 130         for pubKey, node := range consensusNodeMap {
 131                 if block.BlockWitness.Get(node.Order) == nil {
 132                         cachekey := signCacheKey(blockHash.String(), pubKey)
 133                         if signature, ok := c.signatureCache.Get(cachekey); ok {
 134                                 block.Set(node.Order, signature.([]byte))
 135                         } else {
 136                                 continue
 137                         }
 138                 }
 139
 140                 if err := c.checkNodeSign(&block.BlockHeader, node, block.Get(node.Order)); err == errDoubleSignBlock {
 141                         log.WithFields(log.Fields{"module": logModule, "blockHash": blockHash.String(), "pubKey": pubKey}).Warn("the consensus node double sign the same height of different block")
 142                         block.BlockWitness.Delete(node.Order)
 143                         continue
 144                 } else if err != nil {
 145                         return err
 146                 }
 147
 148                 if blocker == pubKey {
 149                         hasBlockerSign = true
 150                 }
 151         }
 152
 153         if !hasBlockerSign {
 154                 return errors.New("the block has no signature of the blocker")
 155         }
 156         return nil
 157 }
 158
 159 // ProcessBlockSignature process the received block signature messages
 160 // return whether a block become irreversible, if so, the chain module must update status
 161 func (c *Chain) ProcessBlockSignature(signature, xPub []byte, blockHash *bc.Hash) error {
 162         xpubStr := hex.EncodeToString(xPub[:])
 163         blockHeader, _ := c.store.GetBlockHeader(blockHash)
 164
 165         // save the signature if the block is not exist
 166         if blockHeader == nil {
 167                 cacheKey := signCacheKey(blockHash.String(), xpubStr)
 168                 c.signatureCache.Add(cacheKey, signature)
 169                 return nil
 170         }
 171
 172         consensusNode, err := c.getConsensusNode(&blockHeader.PreviousBlockHash, xpubStr)
 173         if err != nil {
 174                 return err
 175         }
 176
 177         if blockHeader.BlockWitness.Get(consensusNode.Order) != nil {
 178                 return nil
 179         }
 180
 181         c.cond.L.Lock()
 182         defer c.cond.L.Unlock()
 183         if err := c.checkNodeSign(blockHeader, consensusNode, signature); err != nil {
 184                 return err
 185         }
 186
 187         if err := c.updateBlockSignature(blockHeader, consensusNode.Order, signature); err != nil {
 188                 return err
 189         }
 190         return c.eventDispatcher.Post(event.BlockSignatureEvent{BlockHash: *blockHash, Signature: signature, XPub: xPub})
 191 }
 192
 193 // SignBlock signing the block if current node is consensus node
 194 func (c *Chain) SignBlock(block *types.Block) ([]byte, error) {
 195         xprv := config.CommonConfig.PrivateKey()
 196         xpubStr := xprv.XPub().String()
 197         node, err := c.getConsensusNode(&block.PreviousBlockHash, xpubStr)
 198         if err == errNotFoundConsensusNode {
 199                 return nil, nil
 200         } else if err != nil {
 201                 return nil, err
 202         }
 203
 204         if err := c.checkDoubleSign(&block.BlockHeader, node.XPub.String()); err == errDoubleSignBlock {
 205                 return nil, nil
 206         } else if err != nil {
 207                 return nil, err
 208         }
 209
 210         signature := block.Get(node.Order)
 211         if len(signature) == 0 {
 212                 signature = xprv.Sign(block.Hash().Bytes())
 213                 block.Set(node.Order, signature)
 214         }
 215         return signature, nil
 216 }