package core import ( "bytes" "fmt" "io" "math/big" "runtime" "sync" "sync/atomic" "time" "github.com/ethereum/go-ethereum/common" "github.com/ethereum/go-ethereum/core/state" "github.com/ethereum/go-ethereum/core/types" "github.com/ethereum/go-ethereum/event" "github.com/ethereum/go-ethereum/logger" "github.com/ethereum/go-ethereum/logger/glog" "github.com/ethereum/go-ethereum/params" "github.com/ethereum/go-ethereum/pow" "github.com/ethereum/go-ethereum/rlp" "github.com/rcrowley/go-metrics" ) var ( chainlogger = logger.NewLogger("CHAIN") jsonlogger = logger.NewJsonLogger() blockHashPre = []byte("block-hash-") blockNumPre = []byte("block-num-") blockInsertTimer = metrics.GetOrRegisterTimer("core/BlockInsertions", metrics.DefaultRegistry) ) const ( blockCacheLimit = 10000 maxFutureBlocks = 256 maxTimeFutureBlocks = 30 ) // CalcDifficulty is the difficulty adjustment algorithm. It returns // the difficulty that a new block b should have when created at time // given the parent block's time and difficulty. func CalcDifficulty(time int64, parentTime int64, parentDiff *big.Int) *big.Int { diff := new(big.Int) adjust := new(big.Int).Div(parentDiff, params.DifficultyBoundDivisor) if big.NewInt(time-parentTime).Cmp(params.DurationLimit) < 0 { diff.Add(parentDiff, adjust) } else { diff.Sub(parentDiff, adjust) } if diff.Cmp(params.MinimumDifficulty) < 0 { return params.MinimumDifficulty } return diff } // CalcTD computes the total difficulty of block. func CalcTD(block, parent *types.Block) *big.Int { if parent == nil { return block.Difficulty() } d := block.Difficulty() d.Add(d, parent.Td) return d } // CalcGasLimit computes the gas limit of the next block after parent. // The result may be modified by the caller. func CalcGasLimit(parent *types.Block) *big.Int { decay := new(big.Int).Div(parent.GasLimit(), params.GasLimitBoundDivisor) contrib := new(big.Int).Mul(parent.GasUsed(), big.NewInt(3)) contrib = contrib.Div(contrib, big.NewInt(2)) contrib = contrib.Div(contrib, params.GasLimitBoundDivisor) gl := new(big.Int).Sub(parent.GasLimit(), decay) gl = gl.Add(gl, contrib) gl = gl.Add(gl, big.NewInt(1)) gl.Set(common.BigMax(gl, params.MinGasLimit)) if gl.Cmp(params.GenesisGasLimit) < 0 { gl.Add(parent.GasLimit(), decay) gl.Set(common.BigMin(gl, params.GenesisGasLimit)) } return gl } type ChainManager struct { //eth EthManager blockDb common.Database stateDb common.Database processor types.BlockProcessor eventMux *event.TypeMux genesisBlock *types.Block // Last known total difficulty mu sync.RWMutex chainmu sync.RWMutex tsmu sync.RWMutex td *big.Int currentBlock *types.Block lastBlockHash common.Hash currentGasLimit *big.Int transState *state.StateDB txState *state.ManagedState cache *BlockCache futureBlocks *BlockCache quit chan struct{} // procInterrupt must be atomically called procInterrupt int32 // interrupt signaler for block processing wg sync.WaitGroup pow pow.PoW } func NewChainManager(genesis *types.Block, blockDb, stateDb common.Database, pow pow.PoW, mux *event.TypeMux) (*ChainManager, error) { bc := &ChainManager{ blockDb: blockDb, stateDb: stateDb, genesisBlock: GenesisBlock(42, stateDb), eventMux: mux, quit: make(chan struct{}), cache: NewBlockCache(blockCacheLimit), pow: pow, } // Check the genesis block given to the chain manager. If the genesis block mismatches block number 0 // throw an error. If no block or the same block's found continue. if g := bc.GetBlockByNumber(0); g != nil && g.Hash() != genesis.Hash() { return nil, fmt.Errorf("Genesis mismatch. Maybe different nonce (%d vs %d)? %x / %x", g.Nonce(), genesis.Nonce(), g.Hash().Bytes()[:4], genesis.Hash().Bytes()[:4]) } bc.genesisBlock = genesis 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 { if block := bc.GetBlock(hash); block != nil { glog.V(logger.Error).Infof("Found bad hash. Reorganising chain to state %x\n", block.ParentHash().Bytes()[:4]) block = bc.GetBlock(block.ParentHash()) if block == nil { glog.Fatal("Unable to complete. Parent block not found. Corrupted DB?") } bc.SetHead(block) glog.V(logger.Error).Infoln("Chain reorg was successfull. Resuming normal operation") } } bc.transState = bc.State().Copy() // Take ownership of this particular state bc.txState = state.ManageState(bc.State().Copy()) bc.futureBlocks = NewBlockCache(maxFutureBlocks) bc.makeCache() go bc.update() return bc, nil } func (bc *ChainManager) SetHead(head *types.Block) { bc.mu.Lock() defer bc.mu.Unlock() for block := bc.currentBlock; block != nil && block.Hash() != head.Hash(); block = bc.GetBlock(block.Header().ParentHash) { bc.removeBlock(block) } bc.cache = NewBlockCache(blockCacheLimit) bc.currentBlock = head bc.makeCache() statedb := state.New(head.Root(), bc.stateDb) bc.txState = state.ManageState(statedb) bc.transState = statedb.Copy() bc.setTotalDifficulty(head.Td) bc.insert(head) bc.setLastState() } func (self *ChainManager) Td() *big.Int { self.mu.RLock() defer self.mu.RUnlock() return new(big.Int).Set(self.td) } func (self *ChainManager) GasLimit() *big.Int { self.mu.RLock() defer self.mu.RUnlock() return self.currentBlock.GasLimit() } func (self *ChainManager) LastBlockHash() common.Hash { self.mu.RLock() defer self.mu.RUnlock() return self.lastBlockHash } func (self *ChainManager) CurrentBlock() *types.Block { self.mu.RLock() defer self.mu.RUnlock() return self.currentBlock } func (self *ChainManager) Status() (td *big.Int, currentBlock common.Hash, genesisBlock common.Hash) { self.mu.RLock() defer self.mu.RUnlock() return new(big.Int).Set(self.td), self.currentBlock.Hash(), self.genesisBlock.Hash() } func (self *ChainManager) SetProcessor(proc types.BlockProcessor) { self.processor = proc } func (self *ChainManager) State() *state.StateDB { return state.New(self.CurrentBlock().Root(), self.stateDb) } func (self *ChainManager) TransState() *state.StateDB { self.tsmu.RLock() defer self.tsmu.RUnlock() return self.transState } func (self *ChainManager) setTransState(statedb *state.StateDB) { self.transState = statedb } func (bc *ChainManager) setLastState() { data, _ := bc.blockDb.Get([]byte("LastBlock")) if len(data) != 0 { block := bc.GetBlock(common.BytesToHash(data)) if block != nil { bc.currentBlock = block bc.lastBlockHash = block.Hash() } else { glog.Fatalf("Fatal. LastBlock not found. Please run removedb and resync") } } else { bc.Reset() } bc.td = bc.currentBlock.Td 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) } } func (bc *ChainManager) makeCache() { if bc.cache == nil { bc.cache = NewBlockCache(blockCacheLimit) } // load in last `blockCacheLimit` - 1 blocks. Last block is the current. for _, block := range bc.GetBlocksFromHash(bc.currentBlock.Hash(), blockCacheLimit) { bc.cache.Push(block) } } func (bc *ChainManager) Reset() { bc.mu.Lock() defer bc.mu.Unlock() for block := bc.currentBlock; block != nil; block = bc.GetBlock(block.Header().ParentHash) { bc.removeBlock(block) } if bc.cache == nil { bc.cache = NewBlockCache(blockCacheLimit) } // Prepare the genesis block bc.write(bc.genesisBlock) bc.insert(bc.genesisBlock) bc.currentBlock = bc.genesisBlock bc.makeCache() bc.setTotalDifficulty(common.Big("0")) } func (bc *ChainManager) removeBlock(block *types.Block) { bc.blockDb.Delete(append(blockHashPre, block.Hash().Bytes()...)) } func (bc *ChainManager) ResetWithGenesisBlock(gb *types.Block) { bc.mu.Lock() defer bc.mu.Unlock() for block := bc.currentBlock; block != nil; block = bc.GetBlock(block.Header().ParentHash) { bc.removeBlock(block) } // Prepare the genesis block gb.Td = gb.Difficulty() bc.genesisBlock = gb bc.write(bc.genesisBlock) bc.insert(bc.genesisBlock) bc.currentBlock = bc.genesisBlock bc.makeCache() bc.td = gb.Difficulty() } // Export writes the active chain to the given writer. func (self *ChainManager) Export(w io.Writer) error { if err := self.ExportN(w, uint64(0), self.currentBlock.NumberU64()); err != nil { return err } return nil } // ExportN writes a subset of the active chain to the given writer. func (self *ChainManager) ExportN(w io.Writer, first uint64, last uint64) error { self.mu.RLock() defer self.mu.RUnlock() if first > last { return fmt.Errorf("export failed: first (%d) is greater than last (%d)", first, last) } glog.V(logger.Info).Infof("exporting %d blocks...\n", last-first+1) for nr := first; nr <= last; nr++ { block := self.GetBlockByNumber(nr) if block == nil { return fmt.Errorf("export failed on #%d: not found", nr) } if err := block.EncodeRLP(w); err != nil { return err } } return nil } // insert injects a block into the current chain block chain. Note, this function // assumes that the `mu` mutex is held! func (bc *ChainManager) insert(block *types.Block) { key := append(blockNumPre, block.Number().Bytes()...) err := bc.blockDb.Put(key, block.Hash().Bytes()) if err != nil { glog.Fatal("db write fail:", err) } err = bc.blockDb.Put([]byte("LastBlock"), block.Hash().Bytes()) if err != nil { glog.Fatal("db write fail:", err) } bc.currentBlock = block bc.lastBlockHash = block.Hash() } func (bc *ChainManager) write(block *types.Block) { enc, _ := rlp.EncodeToBytes((*types.StorageBlock)(block)) key := append(blockHashPre, block.Hash().Bytes()...) err := bc.blockDb.Put(key, enc) if err != nil { glog.Fatal("db write fail:", err) } // Push block to cache bc.cache.Push(block) } // Accessors func (bc *ChainManager) Genesis() *types.Block { return bc.genesisBlock } // Block fetching methods func (bc *ChainManager) HasBlock(hash common.Hash) bool { data, _ := bc.blockDb.Get(append(blockHashPre, hash[:]...)) return len(data) != 0 } func (self *ChainManager) GetBlockHashesFromHash(hash common.Hash, max uint64) (chain []common.Hash) { block := self.GetBlock(hash) if block == nil { return } // XXX Could be optimised by using a different database which only holds hashes (i.e., linked list) for i := uint64(0); i < max; i++ { block = self.GetBlock(block.ParentHash()) if block == nil { break } chain = append(chain, block.Hash()) if block.Number().Cmp(common.Big0) <= 0 { break } } return } func (self *ChainManager) GetBlock(hash common.Hash) *types.Block { /* if block := self.cache.Get(hash); block != nil { return block } */ data, _ := self.blockDb.Get(append(blockHashPre, hash[:]...)) if len(data) == 0 { return nil } var block types.StorageBlock if err := rlp.Decode(bytes.NewReader(data), &block); err != nil { glog.V(logger.Error).Infof("invalid block RLP for hash %x: %v", hash, err) return nil } return (*types.Block)(&block) } func (self *ChainManager) GetBlockByNumber(num uint64) *types.Block { self.mu.RLock() defer self.mu.RUnlock() return self.getBlockByNumber(num) } // GetBlocksFromHash returns the block corresponding to hash and up to n-1 ancestors. func (self *ChainManager) GetBlocksFromHash(hash common.Hash, n int) (blocks []*types.Block) { for i := 0; i < n; i++ { block := self.GetBlock(hash) if block == nil { break } blocks = append(blocks, block) hash = block.ParentHash() } return } // non blocking version func (self *ChainManager) getBlockByNumber(num uint64) *types.Block { key, _ := self.blockDb.Get(append(blockNumPre, big.NewInt(int64(num)).Bytes()...)) if len(key) == 0 { return nil } return self.GetBlock(common.BytesToHash(key)) } func (self *ChainManager) GetUnclesInChain(block *types.Block, length int) (uncles []*types.Header) { for i := 0; block != nil && i < length; i++ { uncles = append(uncles, block.Uncles()...) block = self.GetBlock(block.ParentHash()) } return } // setTotalDifficulty updates the TD of the chain manager. Note, this function // assumes that the `mu` mutex is held! func (bc *ChainManager) setTotalDifficulty(td *big.Int) { bc.td = new(big.Int).Set(td) } func (bc *ChainManager) Stop() { close(bc.quit) atomic.StoreInt32(&bc.procInterrupt, 1) bc.wg.Wait() glog.V(logger.Info).Infoln("Chain manager stopped") } type queueEvent struct { queue []interface{} canonicalCount int sideCount int splitCount int } func (self *ChainManager) procFutureBlocks() { var blocks []*types.Block self.futureBlocks.Each(func(i int, block *types.Block) { blocks = append(blocks, block) }) if len(blocks) > 0 { types.BlockBy(types.Number).Sort(blocks) self.InsertChain(blocks) } } // InsertChain will attempt to insert the given chain in to the canonical chain or, otherwise, create a fork. It an error is returned // it will return the index number of the failing block as well an error describing what went wrong (for possible errors see core/errors.go). func (self *ChainManager) InsertChain(chain types.Blocks) (int, error) { self.wg.Add(1) defer self.wg.Done() self.chainmu.Lock() defer self.chainmu.Unlock() // A queued approach to delivering events. This is generally // faster than direct delivery and requires much less mutex // acquiring. var ( queue = make([]interface{}, len(chain)) queueEvent = queueEvent{queue: queue} stats struct{ queued, processed, ignored int } tstart = time.Now() nonceDone = make(chan nonceResult, len(chain)) nonceQuit = make(chan struct{}) nonceChecked = make([]bool, len(chain)) ) // Start the parallel nonce verifier. go verifyNonces(self.pow, chain, nonceQuit, nonceDone) defer close(nonceQuit) txcount := 0 for i, block := range chain { if atomic.LoadInt32(&self.procInterrupt) == 1 { glog.V(logger.Debug).Infoln("Premature abort during chain processing") break } bstart := time.Now() // Wait for block i's nonce to be verified before processing // its state transition. for !nonceChecked[i] { r := <-nonceDone nonceChecked[r.i] = true if !r.valid { block := chain[r.i] return r.i, &BlockNonceErr{Hash: block.Hash(), Number: block.Number(), Nonce: block.Nonce()} } } if BadHashes[block.Hash()] { err := fmt.Errorf("Found known bad hash in chain %x", block.Hash()) blockErr(block, err) return i, err } // Setting block.Td regardless of error (known for example) prevents errors down the line // in the protocol handler block.Td = new(big.Int).Set(CalcTD(block, self.GetBlock(block.ParentHash()))) // Call in to the block processor and check for errors. It's likely that if one block fails // all others will fail too (unless a known block is returned). logs, err := self.processor.Process(block) if err != nil { if IsKnownBlockErr(err) { stats.ignored++ continue } if err == BlockFutureErr { // Allow up to MaxFuture second in the future blocks. If this limit // is exceeded the chain is discarded and processed at a later time // if given. if max := time.Now().Unix() + maxTimeFutureBlocks; block.Time() > max { return i, fmt.Errorf("%v: BlockFutureErr, %v > %v", BlockFutureErr, block.Time(), max) } self.futureBlocks.Push(block) stats.queued++ continue } if IsParentErr(err) && self.futureBlocks.Has(block.ParentHash()) { self.futureBlocks.Push(block) stats.queued++ continue } blockErr(block, err) return i, err } txcount += len(block.Transactions()) cblock := self.currentBlock // 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 { // chain fork if block.ParentHash() != cblock.Hash() { // during split we merge two different chains and create the new canonical chain err := self.merge(cblock, block) if err != nil { return i, err } queue[i] = ChainSplitEvent{block, logs} queueEvent.splitCount++ } self.mu.Lock() self.setTotalDifficulty(block.Td) self.insert(block) self.mu.Unlock() jsonlogger.LogJson(&logger.EthChainNewHead{ BlockHash: block.Hash().Hex(), BlockNumber: block.Number(), ChainHeadHash: cblock.Hash().Hex(), BlockPrevHash: block.ParentHash().Hex(), }) self.setTransState(state.New(block.Root(), self.stateDb)) self.txState.SetState(state.New(block.Root(), self.stateDb)) queue[i] = ChainEvent{block, block.Hash(), logs} queueEvent.canonicalCount++ if glog.V(logger.Debug) { glog.Infof("[%v] inserted block #%d (%d TXs %d UNCs) (%x...). Took %v\n", time.Now().UnixNano(), block.Number(), len(block.Transactions()), len(block.Uncles()), block.Hash().Bytes()[0:4], time.Since(bstart)) } } else { if glog.V(logger.Detail) { glog.Infof("inserted forked block #%d (TD=%v) (%d TXs %d UNCs) (%x...). Took %v\n", block.Number(), block.Difficulty(), len(block.Transactions()), len(block.Uncles()), block.Hash().Bytes()[0:4], time.Since(bstart)) } queue[i] = ChainSideEvent{block, logs} queueEvent.sideCount++ } // Write block to database. Eventually we'll have to improve on this and throw away blocks that are // not in the canonical chain. self.write(block) // Delete from future blocks self.futureBlocks.Delete(block.Hash()) stats.processed++ blockInsertTimer.UpdateSince(bstart) } if (stats.queued > 0 || stats.processed > 0 || stats.ignored > 0) && bool(glog.V(logger.Info)) { tend := time.Since(tstart) start, end := chain[0], chain[len(chain)-1] glog.Infof("imported %d block(s) (%d queued %d ignored) including %d txs in %v. #%v [%x / %x]\n", stats.processed, stats.queued, stats.ignored, txcount, tend, end.Number(), start.Hash().Bytes()[:4], end.Hash().Bytes()[:4]) } go self.eventMux.Post(queueEvent) return 0, nil } // 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) diff(oldBlock, newBlock *types.Block) (types.Blocks, error) { var ( newChain types.Blocks commonBlock *types.Block oldStart = oldBlock newStart = newBlock ) // first reduce whoever is higher bound if oldBlock.NumberU64() > newBlock.NumberU64() { // reduce old chain for oldBlock = oldBlock; oldBlock != nil && oldBlock.NumberU64() != newBlock.NumberU64(); oldBlock = self.GetBlock(oldBlock.ParentHash()) { } } else { // reduce new chain and append new chain blocks for inserting later on for newBlock = newBlock; newBlock != nil && newBlock.NumberU64() != oldBlock.NumberU64(); newBlock = self.GetBlock(newBlock.ParentHash()) { newChain = append(newChain, newBlock) } } if oldBlock == nil { return nil, fmt.Errorf("Invalid old chain") } if newBlock == nil { return nil, fmt.Errorf("Invalid new chain") } numSplit := newBlock.Number() for { if oldBlock.Hash() == newBlock.Hash() { commonBlock = oldBlock break } newChain = append(newChain, newBlock) oldBlock, newBlock = self.GetBlock(oldBlock.ParentHash()), self.GetBlock(newBlock.ParentHash()) if oldBlock == nil { return nil, fmt.Errorf("Invalid old chain") } if newBlock == nil { return nil, fmt.Errorf("Invalid new chain") } } if glog.V(logger.Info) { commonHash := commonBlock.Hash() glog.Infof("Fork detected @ %x. Reorganising chain from #%v %x to %x", commonHash[:4], numSplit, oldStart.Hash().Bytes()[:4], newStart.Hash().Bytes()[:4]) } return newChain, nil } // merge merges two different chain to the new canonical chain func (self *ChainManager) merge(oldBlock, newBlock *types.Block) error { newChain, err := self.diff(oldBlock, newBlock) if err != nil { return fmt.Errorf("chain reorg failed: %v", err) } // insert blocks. Order does not matter. Last block will be written in ImportChain itself which creates the new head properly self.mu.Lock() for _, block := range newChain { self.insert(block) } self.mu.Unlock() return nil } func (self *ChainManager) update() { events := self.eventMux.Subscribe(queueEvent{}) futureTimer := time.Tick(5 * time.Second) out: for { select { case ev := <-events.Chan(): switch ev := ev.(type) { case queueEvent: for _, event := range ev.queue { switch event := event.(type) { case ChainEvent: // We need some control over the mining operation. Acquiring locks and waiting for the miner to create new block takes too long // and in most cases isn't even necessary. if self.lastBlockHash == event.Hash { self.currentGasLimit = CalcGasLimit(event.Block) self.eventMux.Post(ChainHeadEvent{event.Block}) } } self.eventMux.Post(event) } } case <-futureTimer: self.procFutureBlocks() case <-self.quit: break out } } } func blockErr(block *types.Block, err error) { h := block.Header() glog.V(logger.Error).Infof("Bad block #%v (%x)\n", h.Number, h.Hash().Bytes()) glog.V(logger.Error).Infoln(err) glog.V(logger.Debug).Infoln(verifyNonces) } type nonceResult struct { i int valid bool } // block verifies nonces of the given blocks in parallel and returns // an error if one of the blocks nonce verifications failed. func verifyNonces(pow pow.PoW, blocks []*types.Block, quit <-chan struct{}, done chan<- nonceResult) { // Spawn a few workers. They listen for blocks on the in channel // and send results on done. The workers will exit in the // background when in is closed. var ( in = make(chan int) nworkers = runtime.GOMAXPROCS(0) ) defer close(in) if len(blocks) < nworkers { nworkers = len(blocks) } for i := 0; i < nworkers; i++ { go func() { for i := range in { done <- nonceResult{i: i, valid: pow.Verify(blocks[i])} } }() } // Feed block indices to the workers. for i := range blocks { select { case in <- i: continue case <-quit: return } } }