Merge pull request ethereum#288 from nextyio/consensus-sync

Resolve chain desync due to chain fork

Author: Zergity

consensus/dccs/2_dccs.go

@@ -277,6 +277,18 @@ func (c *Context) verifySeal2() error {
 	return nil
 }
 
+func (c *Context) getHeader(hash common.Hash, number uint64) *types.Header {
+	header := c.getHeaderByNumber(number)
+	if header != nil && header.Hash() == hash {
+		return header
+	}
+	header = c.getHeaderByHash(hash)
+	if header != nil && header.Number.Uint64() == number {
+		return header
+	}
+	return nil
+}
+
 // getHeaderByNumber returns either:
 // + the context head, if number == head.Number
 // + the header in parents if available (nessesary for batch headers processing)

consensus/dccs/2_queue.go

@@ -257,6 +257,7 @@ func (c *Context) getSealingQueue(parentHash common.Hash) (*SealingQueue, error)
 	}
 
 	var maxDiff uint64
+	hash := parentHash
 
 	// scan backward atmost LeakDurations blocks from number
 	for i := uint64(0); i < c.engine.config.LeakDuration; i++ {
@@ -275,9 +276,9 @@ func (c *Context) getSealingQueue(parentHash common.Hash) (*SealingQueue, error)
 		// TODO: optimization for leakage case
 
 		n := number - i
-		header := c.getHeaderByNumber(n)
+		header := c.getHeader(hash, n)
 		if header == nil {
-			log.Error("getSealingQueue: getHeaderByNumber returns nil", "n", n, "len(parents)", len(c.parents))
+			log.Error("Header not found", "number", n, "hash", hash, "len(parents)", len(c.parents))
 			return nil, errUnknownBlock
 		}
 		sealer, err := c.ecrecover(header)
@@ -295,6 +296,9 @@ func (c *Context) getSealingQueue(parentHash common.Hash) (*SealingQueue, error)
 		if i < minBlockToScan || len(recents) < int(maxDiff)/2 {
 			addRecent(sealer)
 		}
+
+		// next parent in the hash chain
+		hash = header.ParentHash
 	}
 
 	apps, err := c.crawlSealerApplications(parent)

core/blockchain.go

@@ -1378,8 +1378,7 @@ func (bc *BlockChain) writeBlockWithState(block *types.Block, receipts []*types.
 
 // ChainCompare compares the weight of remote chain to local chain.
 func ChainCompare(remoteTD, localTD *big.Int, remoteHash, localHash common.Hash) int {
-	cmp := remoteTD.Cmp(localTD)
-	if cmp != 0 {
+	if cmp := remoteTD.Cmp(localTD); cmp != 0 {
 		return cmp
 	}
 	return bytes.Compare(localHash.Bytes(), remoteHash.Bytes())
@@ -1495,7 +1494,7 @@ func (bc *BlockChain) insertChain(chain types.Blocks, verifySeals bool) (int, []
 		)
 		for block != nil && err == ErrKnownBlock {
 			externTd = new(big.Int).Add(externTd, block.Difficulty())
-			if localTd.Cmp(externTd) < 0 {
+			if ChainCompare(localTd, externTd, current.Hash(), block.Hash()) < 0 {
 				break
 			}
 			log.Debug("Ignoring already known block", "number", block.Number(), "hash", block.Hash())
@@ -1787,7 +1786,7 @@ func (bc *BlockChain) insertSideChain(block *types.Block, it *insertIterator) (i
 	// If the externTd was larger than our local TD, we now need to reimport the previous
 	// blocks to regenerate the required state
 	localTd := bc.GetTd(current.Hash(), current.NumberU64())
-	if localTd.Cmp(externTd) > 0 {
+	if ChainCompare(localTd, externTd, current.Hash(), block.Hash()) > 0 {
 		log.Info("Sidechain written to disk", "start", it.first().NumberU64(), "end", it.previous().Number, "sidetd", externTd, "localtd", localTd)
 		return it.index, nil, nil, err
 	}

core/headerchain.go

@@ -280,7 +280,7 @@ func (hc *HeaderChain) InsertHeaderChain(chain []*types.Header, writeHeader WhCa
 		if hc.HasHeader(hash, header.Number.Uint64()) {
 			externTd := hc.GetTd(hash, header.Number.Uint64())
 			localTd := hc.GetTd(hc.currentHeaderHash, hc.CurrentHeader().Number.Uint64())
-			if externTd == nil || externTd.Cmp(localTd) <= 0 {
+			if externTd == nil || ChainCompare(externTd, localTd, hash, hc.currentHeaderHash) <= 0 {
 				stats.ignored++
 				continue
 			}