Merge pull request #825 from obscuren/develop

core: chain fork fix

6 files changed, 117 insertions, 35 deletions

diff --git a/cmd/geth/main.go b/cmd/geth/main.go
index bec47efbb..365390a07 100644
--- a/cmd/geth/main.go
+++ b/cmd/geth/main.go
@@ -47,7 +47,7 @@ import _ "net/http/pprof"
 
 const (
 	ClientIdentifier = "Geth"
-	Version          = "0.9.12"
+	Version          = "0.9.13"
 )
 
 var (
diff --git a/core/chain_manager.go b/core/chain_manager.go
index fb2af0280..32ad4a2ba 100644
--- a/core/chain_manager.go
+++ b/core/chain_manager.go
@@ -74,8 +74,9 @@ type ChainManager struct {
 	eventMux     *event.TypeMux
 	genesisBlock *types.Block
 	// Last known total difficulty
-	mu              sync.RWMutex
-	tsmu            sync.RWMutex
+	mu   sync.RWMutex
+	tsmu sync.RWMutex
+
 	td              *big.Int
 	currentBlock    *types.Block
 	lastBlockHash   common.Hash
@@ -92,15 +93,14 @@ type ChainManager struct {
 
 func NewChainManager(blockDb, stateDb common.Database, mux *event.TypeMux) *ChainManager {
 	bc := &ChainManager{
-		blockDb:         blockDb,
-		stateDb:         stateDb,
-		genesisBlock:    GenesisBlock(stateDb),
-		eventMux:        mux,
-		quit:            make(chan struct{}),
-		cache:           NewBlockCache(blockCacheLimit),
-		currentGasLimit: new(big.Int),
+		blockDb:      blockDb,
+		stateDb:      stateDb,
+		genesisBlock: GenesisBlock(stateDb),
+		eventMux:     mux,
+		quit:         make(chan struct{}),
+		cache:        NewBlockCache(blockCacheLimit),
 	}
-	bc.setLastBlock()
+	bc.setLastState()
 
 	// Check the current state of the block hashes and make sure that we do not have any of the bad blocks in our chain
 	for _, hash := range badHashes {
@@ -145,7 +145,7 @@ func (bc *ChainManager) SetHead(head *types.Block) {
 	bc.transState = statedb.Copy()
 	bc.setTotalDifficulty(head.Td)
 	bc.insert(head)
-	bc.setLastBlock()
+	bc.setLastState()
 }
 
 func (self *ChainManager) Td() *big.Int {
@@ -212,7 +212,7 @@ func (self *ChainManager) setTransState(statedb *state.StateDB) {
 	self.transState = statedb
 }
 
-func (bc *ChainManager) setLastBlock() {
+func (bc *ChainManager) setLastState() {
 	data, _ := bc.blockDb.Get([]byte("LastBlock"))
 	if len(data) != 0 {
 		block := bc.GetBlock(common.BytesToHash(data))
@@ -224,6 +224,7 @@ func (bc *ChainManager) setLastBlock() {
 	} else {
 		bc.Reset()
 	}
+	bc.currentGasLimit = CalcGasLimit(bc.currentBlock)
 
 	if glog.V(logger.Info) {
 		glog.Infof("Last block (#%v) %x TD=%v\n", bc.currentBlock.Number(), bc.currentBlock.Hash(), bc.td)
@@ -319,6 +320,7 @@ func (bc *ChainManager) ResetWithGenesisBlock(gb *types.Block) {
 	bc.insert(bc.genesisBlock)
 	bc.currentBlock = bc.genesisBlock
 	bc.makeCache()
+	bc.td = gb.Difficulty()
 }
 
 // Export writes the active chain to the given writer.
@@ -346,8 +348,6 @@ func (self *ChainManager) Export(w io.Writer) error {
 func (bc *ChainManager) insert(block *types.Block) {
 	key := append(blockNumPre, block.Number().Bytes()...)
 	bc.blockDb.Put(key, block.Hash().Bytes())
-	// Push block to cache
-	bc.cache.Push(block)
 
 	bc.blockDb.Put([]byte("LastBlock"), block.Hash().Bytes())
 	bc.currentBlock = block
@@ -358,6 +358,8 @@ func (bc *ChainManager) write(block *types.Block) {
 	enc, _ := rlp.EncodeToBytes((*types.StorageBlock)(block))
 	key := append(blockHashPre, block.Hash().Bytes()...)
 	bc.blockDb.Put(key, enc)
+	// Push block to cache
+	bc.cache.Push(block)
 }
 
 // Accessors
@@ -552,16 +554,17 @@ func (self *ChainManager) InsertChain(chain types.Blocks) error {
 			// Compare the TD of the last known block in the canonical chain to make sure it's greater.
 			// At this point it's possible that a different chain (fork) becomes the new canonical chain.
 			if block.Td.Cmp(self.td) > 0 {
-				//if block.Header().Number.Cmp(new(big.Int).Add(cblock.Header().Number, common.Big1)) < 0 {
-				if block.Number().Cmp(cblock.Number()) <= 0 {
+				// Check for chain forks. If H(block.num - 1) != block.parent, we're on a fork and need to do some merging
+				if previous := self.getBlockByNumber(block.NumberU64() - 1); previous.Hash() != block.ParentHash() {
 					chash := cblock.Hash()
 					hash := block.Hash()
 
 					if glog.V(logger.Info) {
 						glog.Infof("Split detected. New head #%v (%x) TD=%v, was #%v (%x) TD=%v\n", block.Header().Number, hash[:4], block.Td, cblock.Header().Number, chash[:4], self.td)
 					}
+
 					// during split we merge two different chains and create the new canonical chain
-					self.merge(self.getBlockByNumber(block.NumberU64()), block)
+					self.merge(previous, block)
 
 					queue[i] = ChainSplitEvent{block, logs}
 					queueEvent.splitCount++
@@ -587,16 +590,19 @@ func (self *ChainManager) InsertChain(chain types.Blocks) error {
 					glog.Infof("inserted block #%d (%d TXs %d UNCs) (%x...)\n", block.Number(), len(block.Transactions()), len(block.Uncles()), block.Hash().Bytes()[0:4])
 				}
 			} else {
+				if glog.V(logger.Detail) {
+					glog.Infof("inserted forked block #%d (%d TXs %d UNCs) (%x...)\n", block.Number(), len(block.Transactions()), len(block.Uncles()), block.Hash().Bytes()[0:4])
+				}
+
 				queue[i] = ChainSideEvent{block, logs}
 				queueEvent.sideCount++
 			}
+			self.futureBlocks.Delete(block.Hash())
 		}
 		self.mu.Unlock()
 
 		stats.processed++
 
-		self.futureBlocks.Delete(block.Hash())
-
 	}
 
 	if (stats.queued > 0 || stats.processed > 0) && bool(glog.V(logger.Info)) {
@@ -610,33 +616,38 @@ func (self *ChainManager) InsertChain(chain types.Blocks) error {
 	return nil
 }
 
-// merge takes two blocks, an old chain and a new chain and will reconstruct the blocks and inserts them
+// diff takes two blocks, an old chain and a new chain and will reconstruct the blocks and inserts them
 // to be part of the new canonical chain.
-func (self *ChainManager) merge(oldBlock, newBlock *types.Block) {
+func (self *ChainManager) diff(oldBlock, newBlock *types.Block) types.Blocks {
 	glog.V(logger.Debug).Infof("Applying diff to %x & %x\n", oldBlock.Hash().Bytes()[:4], newBlock.Hash().Bytes()[:4])
 
-	var oldChain, newChain types.Blocks
-	// First find the split (common ancestor) so we can perform an adequate merge
+	var newChain types.Blocks
+	// first find common number
+	for newBlock = newBlock; newBlock.NumberU64() != oldBlock.NumberU64(); newBlock = self.GetBlock(newBlock.ParentHash()) {
+		newChain = append(newChain, newBlock)
+	}
+
+	glog.V(logger.Debug).Infoln("Found common number", newBlock.Number())
 	for {
-		oldBlock, newBlock = self.GetBlock(oldBlock.ParentHash()), self.GetBlock(newBlock.ParentHash())
 		if oldBlock.Hash() == newBlock.Hash() {
 			break
 		}
-		oldChain = append(oldChain, oldBlock)
 		newChain = append(newChain, newBlock)
+
+		oldBlock, newBlock = self.GetBlock(oldBlock.ParentHash()), self.GetBlock(newBlock.ParentHash())
 	}
 
+	return newChain
+}
+
+// merge merges two different chain to the new canonical chain
+func (self *ChainManager) merge(oldBlock, newBlock *types.Block) {
+	newChain := self.diff(oldBlock, newBlock)
+
 	// insert blocks
 	for _, block := range newChain {
 		self.insert(block)
 	}
-
-	if glog.V(logger.Detail) {
-		for i, oldBlock := range oldChain {
-			glog.Infof("- %.10v   = %x\n", oldBlock.Number(), oldBlock.Hash())
-			glog.Infof("+ %.10v   = %x\n", newChain[i].Number(), newChain[i].Hash())
-		}
-	}
 }
 
 func (self *ChainManager) update() {
diff --git a/core/chain_manager_test.go b/core/chain_manager_test.go
index c2911150a..a88afd7c8 100644
--- a/core/chain_manager_test.go
+++ b/core/chain_manager_test.go
@@ -9,6 +9,7 @@ import (
 	"strconv"
 	"testing"
 
+	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/event"
@@ -56,12 +57,14 @@ func testFork(t *testing.T, bman *BlockProcessor, i, N int, f func(td1, td2 *big
 	}
 	// Compare difficulties
 	f(tdpre, td)
+
+	// Loop over parents making sure reconstruction is done properly
 }
 
 func printChain(bc *ChainManager) {
 	for i := bc.CurrentBlock().Number().Uint64(); i > 0; i-- {
 		b := bc.GetBlockByNumber(uint64(i))
-		fmt.Printf("\t%x\n", b.Hash())
+		fmt.Printf("\t%x %v\n", b.Hash(), b.Difficulty())
 	}
 }
 
@@ -344,3 +347,50 @@ func TestGetAncestors(t *testing.T) {
 	ancestors := chainMan.GetAncestors(chain[len(chain)-1], 4)
 	fmt.Println(ancestors)
 }
+
+type bproc struct{}
+
+func (bproc) Process(*types.Block) (state.Logs, error) { return nil, nil }
+
+func makeChainWithDiff(genesis *types.Block, d []int, seed byte) []*types.Block {
+	var chain []*types.Block
+	for i, difficulty := range d {
+		header := &types.Header{Number: big.NewInt(int64(i + 1)), Difficulty: big.NewInt(int64(difficulty))}
+		block := types.NewBlockWithHeader(header)
+		copy(block.HeaderHash[:2], []byte{byte(i + 1), seed})
+		if i == 0 {
+			block.ParentHeaderHash = genesis.Hash()
+		} else {
+			copy(block.ParentHeaderHash[:2], []byte{byte(i), seed})
+		}
+
+		chain = append(chain, block)
+	}
+	return chain
+}
+
+func TestReorg(t *testing.T) {
+	db, _ := ethdb.NewMemDatabase()
+	var eventMux event.TypeMux
+
+	genesis := GenesisBlock(db)
+	bc := &ChainManager{blockDb: db, stateDb: db, genesisBlock: genesis, eventMux: &eventMux}
+	bc.cache = NewBlockCache(100)
+	bc.futureBlocks = NewBlockCache(100)
+	bc.processor = bproc{}
+	bc.ResetWithGenesisBlock(genesis)
+	bc.txState = state.ManageState(bc.State())
+
+	chain1 := makeChainWithDiff(genesis, []int{1, 2, 4}, 10)
+	chain2 := makeChainWithDiff(genesis, []int{1, 2, 3, 4}, 11)
+
+	bc.InsertChain(chain1)
+	bc.InsertChain(chain2)
+
+	prev := bc.CurrentBlock()
+	for block := bc.GetBlockByNumber(bc.CurrentBlock().NumberU64() - 1); block.NumberU64() != 0; prev, block = block, bc.GetBlockByNumber(block.NumberU64()-1) {
+		if prev.ParentHash() != block.Hash() {
+			t.Errorf("parent hash mismatch %x - %x", prev.ParentHash(), block.Hash())
+		}
+	}
+}
diff --git a/core/types/block.go b/core/types/block.go
index fa83fc8e8..19cf49c12 100644
--- a/core/types/block.go
+++ b/core/types/block.go
@@ -351,7 +351,7 @@ func (self *Block) Copy() *Block {
 }
 
 func (self *Block) String() string {
-	return fmt.Sprintf(`Block(#%v): Size: %v TD: %v {
+	str := fmt.Sprintf(`Block(#%v): Size: %v TD: %v {
 MinerHash: %x
 %v
 Transactions:
@@ -360,6 +360,16 @@ Uncles:
 %v
 }
 `, self.Number(), self.Size(), self.Td, self.header.HashNoNonce(), self.header, self.transactions, self.uncles)
+
+	if (self.HeaderHash != common.Hash{}) {
+		str += fmt.Sprintf("\nFake hash = %x", self.HeaderHash)
+	}
+
+	if (self.ParentHeaderHash != common.Hash{}) {
+		str += fmt.Sprintf("\nFake parent hash = %x", self.ParentHeaderHash)
+	}
+
+	return str
 }
 
 func (self *Header) String() string {
diff --git a/eth/downloader/downloader.go b/eth/downloader/downloader.go
index 60d908758..a3917854f 100644
--- a/eth/downloader/downloader.go
+++ b/eth/downloader/downloader.go
@@ -436,6 +436,8 @@ func (d *Downloader) process(peer *peer) error {
 		if err != nil && core.IsParentErr(err) {
 			glog.V(logger.Debug).Infoln("Aborting process due to missing parent.")
 
+			// XXX this needs a lot of attention
+			blocks = nil
 			break
 		} else if err != nil {
 			// immediatly unregister the false peer but do not disconnect
@@ -472,3 +474,7 @@ func (d *Downloader) isProcessing() bool {
 func (d *Downloader) isBusy() bool {
 	return d.isFetchingHashes() || d.isDownloadingBlocks() || d.isProcessing()
 }
+
+func (d *Downloader) IsBusy() bool {
+	return d.isBusy()
+}
diff --git a/eth/handler.go b/eth/handler.go
index d00d00f23..61149049e 100644
--- a/eth/handler.go
+++ b/eth/handler.go
@@ -163,6 +163,11 @@ func (pm *ProtocolManager) synchronise(peer *peer) {
 	if peer.td.Cmp(pm.chainman.Td()) <= 0 {
 		return
 	}
+	// Check downloader if it's busy so it doesn't show the sync message
+	// for every attempty
+	if pm.downloader.IsBusy() {
+		return
+	}
 
 	glog.V(logger.Info).Infof("Synchronisation attempt using %s TD=%v\n", peer.id, peer.td)
 	// Get the hashes from the peer (synchronously)