package eth // XXX Fair warning, most of the code is re-used from the old protocol. Please be aware that most of this will actually change // The idea is that most of the calls within the protocol will become synchronous. // Block downloading and block processing will be complete seperate processes /* # Possible scenarios // Synching scenario // Use the best peer to synchronise blocks, err := pm.downloader.Synchronise() if err != nil { // handle break } pm.chainman.InsertChain(blocks) // Receiving block with known parent if parent_exist { if err := pm.chainman.InsertChain(block); err != nil { // handle break } pm.BroadcastBlock(block) } // Receiving block with unknown parent blocks, err := pm.downloader.SynchroniseWithPeer(peer) if err != nil { // handle break } pm.chainman.InsertChain(blocks) */ import ( "fmt" "math" "math/big" "sync" "time" "github.com/ethereum/go-ethereum/common" "github.com/ethereum/go-ethereum/core" "github.com/ethereum/go-ethereum/core/types" "github.com/ethereum/go-ethereum/eth/downloader" "github.com/ethereum/go-ethereum/event" "github.com/ethereum/go-ethereum/logger" "github.com/ethereum/go-ethereum/logger/glog" "github.com/ethereum/go-ethereum/p2p" "github.com/ethereum/go-ethereum/rlp" ) const ( peerCountTimeout = 12 * time.Second // Amount of time it takes for the peer handler to ignore minDesiredPeerCount minDesiredPeerCount = 5 // Amount of peers desired to start syncing ) func errResp(code errCode, format string, v ...interface{}) error { return fmt.Errorf("%v - %v", code, fmt.Sprintf(format, v...)) } type hashFetcherFn func(common.Hash) error type blockFetcherFn func([]common.Hash) error // extProt is an interface which is passed around so we can expose GetHashes and GetBlock without exposing it to the rest of the protocol // extProt is passed around to peers which require to GetHashes and GetBlocks type extProt struct { getHashes hashFetcherFn getBlocks blockFetcherFn } func (ep extProt) GetHashes(hash common.Hash) error { return ep.getHashes(hash) } func (ep extProt) GetBlock(hashes []common.Hash) error { return ep.getBlocks(hashes) } type ProtocolManager struct { protVer, netId int txpool txPool chainman *core.ChainManager downloader *downloader.Downloader pmu sync.Mutex peers map[string]*peer SubProtocol p2p.Protocol eventMux *event.TypeMux txSub event.Subscription minedBlockSub event.Subscription newPeerCh chan *peer quitSync chan struct{} } // NewProtocolManager returns a new ethereum sub protocol manager. The Ethereum sub protocol manages peers capable // with the ethereum network. func NewProtocolManager(protocolVersion, networkId int, mux *event.TypeMux, txpool txPool, chainman *core.ChainManager, downloader *downloader.Downloader) *ProtocolManager { manager := &ProtocolManager{ eventMux: mux, txpool: txpool, chainman: chainman, downloader: downloader, peers: make(map[string]*peer), newPeerCh: make(chan *peer, 1), quitSync: make(chan struct{}), } manager.SubProtocol = p2p.Protocol{ Name: "eth", Version: uint(protocolVersion), Length: ProtocolLength, Run: func(p *p2p.Peer, rw p2p.MsgReadWriter) error { peer := manager.newPeer(protocolVersion, networkId, p, rw) manager.newPeerCh <- peer return manager.handle(peer) }, } return manager } func (pm *ProtocolManager) syncHandler() { // itimer is used to determine when to start ignoring `minDesiredPeerCount` itimer := time.NewTimer(peerCountTimeout) out: for { select { case <-pm.newPeerCh: // Meet the `minDesiredPeerCount` before we select our best peer if len(pm.peers) < minDesiredPeerCount { break } // Find the best peer peer := getBestPeer(pm.peers) if peer == nil { glog.V(logger.Debug).Infoln("Sync attempt cancelled. No peers available") } itimer.Stop() go pm.synchronise(peer) case <-itimer.C: // The timer will make sure that the downloader keeps an active state // in which it attempts to always check the network for highest td peers // Either select the peer or restart the timer if no peers could // be selected. if peer := getBestPeer(pm.peers); peer != nil { go pm.synchronise(peer) } else { itimer.Reset(5 * time.Second) } case <-pm.quitSync: break out } } } func (pm *ProtocolManager) synchronise(peer *peer) { // Make sure the peer's TD is higher than our own. If not drop. if peer.td.Cmp(pm.chainman.Td()) <= 0 { return } glog.V(logger.Info).Infof("Synchronisation attempt using %s TD=%v\n", peer.id, peer.td) // Get the hashes from the peer (synchronously) err := pm.downloader.Synchronise(peer.id, peer.recentHash) if err != nil { // handle error glog.V(logger.Debug).Infoln("error downloading:", err) } } func (pm *ProtocolManager) Start() { // broadcast transactions pm.txSub = pm.eventMux.Subscribe(core.TxPreEvent{}) go pm.txBroadcastLoop() // broadcast mined blocks pm.minedBlockSub = pm.eventMux.Subscribe(core.NewMinedBlockEvent{}) go pm.minedBroadcastLoop() // sync handler go pm.syncHandler() } func (pm *ProtocolManager) Stop() { pm.txSub.Unsubscribe() // quits txBroadcastLoop pm.minedBlockSub.Unsubscribe() // quits blockBroadcastLoop close(pm.quitSync) // quits the sync handler } func (pm *ProtocolManager) newPeer(pv, nv int, p *p2p.Peer, rw p2p.MsgReadWriter) *peer { td, current, genesis := pm.chainman.Status() return newPeer(pv, nv, genesis, current, td, p, rw) } func (pm *ProtocolManager) handle(p *peer) error { if err := p.handleStatus(); err != nil { return err } pm.pmu.Lock() pm.peers[p.id] = p pm.pmu.Unlock() pm.downloader.RegisterPeer(p.id, p.recentHash, p.requestHashes, p.requestBlocks) defer func() { pm.pmu.Lock() defer pm.pmu.Unlock() delete(pm.peers, p.id) pm.downloader.UnregisterPeer(p.id) }() // propagate existing transactions. new transactions appearing // after this will be sent via broadcasts. if err := p.sendTransactions(pm.txpool.GetTransactions()); err != nil { return err } // main loop. handle incoming messages. for { if err := pm.handleMsg(p); err != nil { return err } } return nil } func (self *ProtocolManager) handleMsg(p *peer) error { msg, err := p.rw.ReadMsg() if err != nil { return err } if msg.Size > ProtocolMaxMsgSize { return errResp(ErrMsgTooLarge, "%v > %v", msg.Size, ProtocolMaxMsgSize) } // make sure that the payload has been fully consumed defer msg.Discard() switch msg.Code { case GetTxMsg: // ignore case StatusMsg: return errResp(ErrExtraStatusMsg, "uncontrolled status message") case TxMsg: // TODO: rework using lazy RLP stream var txs []*types.Transaction if err := msg.Decode(&txs); err != nil { return errResp(ErrDecode, "msg %v: %v", msg, err) } for i, tx := range txs { if tx == nil { return errResp(ErrDecode, "transaction %d is nil", i) } jsonlogger.LogJson(&logger.EthTxReceived{ TxHash: tx.Hash().Hex(), RemoteId: p.ID().String(), }) } self.txpool.AddTransactions(txs) case GetBlockHashesMsg: var request getBlockHashesMsgData if err := msg.Decode(&request); err != nil { return errResp(ErrDecode, "->msg %v: %v", msg, err) } if request.Amount > maxHashes { request.Amount = maxHashes } hashes := self.chainman.GetBlockHashesFromHash(request.Hash, request.Amount) if glog.V(logger.Debug) { if len(hashes) == 0 { glog.Infof("invalid block hash %x", request.Hash.Bytes()[:4]) } } // returns either requested hashes or nothing (i.e. not found) return p.sendBlockHashes(hashes) case BlockHashesMsg: msgStream := rlp.NewStream(msg.Payload, uint64(msg.Size)) var hashes []common.Hash if err := msgStream.Decode(&hashes); err != nil { break } err := self.downloader.AddHashes(p.id, hashes) if err != nil { glog.V(logger.Debug).Infoln(err) } case GetBlocksMsg: var blocks []*types.Block msgStream := rlp.NewStream(msg.Payload, uint64(msg.Size)) if _, err := msgStream.List(); err != nil { return err } var i int for { i++ var hash common.Hash err := msgStream.Decode(&hash) if err == rlp.EOL { break } else if err != nil { return errResp(ErrDecode, "msg %v: %v", msg, err) } block := self.chainman.GetBlock(hash) if block != nil { blocks = append(blocks, block) } if i == maxBlocks { break } } return p.sendBlocks(blocks) case BlocksMsg: var blocks []*types.Block msgStream := rlp.NewStream(msg.Payload, uint64(msg.Size)) if err := msgStream.Decode(&blocks); err != nil { glog.V(logger.Detail).Infoln("Decode error", err) blocks = nil } self.downloader.DeliverChunk(p.id, blocks) case NewBlockMsg: var request newBlockMsgData if err := msg.Decode(&request); err != nil { return errResp(ErrDecode, "%v: %v", msg, err) } if err := request.Block.ValidateFields(); err != nil { return errResp(ErrDecode, "block validation %v: %v", msg, err) } hash := request.Block.Hash() // Add the block hash as a known hash to the peer. This will later be used to determine // who should receive this. p.blockHashes.Add(hash) _, chainHead, _ := self.chainman.Status() jsonlogger.LogJson(&logger.EthChainReceivedNewBlock{ BlockHash: hash.Hex(), BlockNumber: request.Block.Number(), // this surely must be zero ChainHeadHash: chainHead.Hex(), BlockPrevHash: request.Block.ParentHash().Hex(), RemoteId: p.ID().String(), }) // Make sure the block isn't already known. If this is the case simply drop // the message and move on. If the TD is < currentTd; drop it as well. If this // chain at some point becomes canonical, the downloader will fetch it. if self.chainman.HasBlock(hash) { break } if self.chainman.Td().Cmp(request.TD) > 0 && new(big.Int).Add(request.Block.Number(), big.NewInt(7)).Cmp(self.chainman.CurrentBlock().Number()) < 0 { glog.V(logger.Debug).Infof("[%s] dropped block %v due to low TD %v\n", p.id, request.Block.Number(), request.TD) break } // Attempt to insert the newly received by checking if the parent exists. // if the parent exists we process the block and propagate to our peers // if the parent does not exists we delegate to the downloader. if self.chainman.HasBlock(request.Block.ParentHash()) { if err := self.chainman.InsertChain(types.Blocks{request.Block}); err != nil { // handle error return nil } self.BroadcastBlock(hash, request.Block) } else { // adding blocks is synchronous go func() { // TODO check parent error err := self.downloader.AddBlock(p.id, request.Block, request.TD) if err != nil { glog.V(logger.Detail).Infoln("downloader err:", err) return } self.BroadcastBlock(hash, request.Block) }() } default: return errResp(ErrInvalidMsgCode, "%v", msg.Code) } return nil } // BroadcastBlock will propagate the block to its connected peers. It will sort // out which peers do not contain the block in their block set and will do a // sqrt(peers) to determine the amount of peers we broadcast to. func (pm *ProtocolManager) BroadcastBlock(hash common.Hash, block *types.Block) { pm.pmu.Lock() defer pm.pmu.Unlock() // Find peers who don't know anything about the given hash. Peers that // don't know about the hash will be a candidate for the broadcast loop var peers []*peer for _, peer := range pm.peers { if !peer.blockHashes.Has(hash) { peers = append(peers, peer) } } // Broadcast block to peer set peers = peers[:int(math.Sqrt(float64(len(peers))))] for _, peer := range peers { peer.sendNewBlock(block) } glog.V(logger.Detail).Infoln("broadcast block to", len(peers), "peers") } // BroadcastTx will propagate the block to its connected peers. It will sort // out which peers do not contain the block in their block set and will do a // sqrt(peers) to determine the amount of peers we broadcast to. func (pm *ProtocolManager) BroadcastTx(hash common.Hash, tx *types.Transaction) { pm.pmu.Lock() defer pm.pmu.Unlock() // Find peers who don't know anything about the given hash. Peers that // don't know about the hash will be a candidate for the broadcast loop var peers []*peer for _, peer := range pm.peers { if !peer.txHashes.Has(hash) { peers = append(peers, peer) } } // Broadcast block to peer set peers = peers[:int(math.Sqrt(float64(len(peers))))] for _, peer := range peers { peer.sendTransaction(tx) } glog.V(logger.Detail).Infoln("broadcast tx to", len(peers), "peers") } // Mined broadcast loop func (self *ProtocolManager) minedBroadcastLoop() { // automatically stops if unsubscribe for obj := range self.minedBlockSub.Chan() { switch ev := obj.(type) { case core.NewMinedBlockEvent: self.BroadcastBlock(ev.Block.Hash(), ev.Block) } } } func (self *ProtocolManager) txBroadcastLoop() { // automatically stops if unsubscribe for obj := range self.txSub.Chan() { event := obj.(core.TxPreEvent) self.BroadcastTx(event.Tx.Hash(), event.Tx) } }