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" "sync" "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/logger" "github.com/ethereum/go-ethereum/logger/glog" "github.com/ethereum/go-ethereum/p2p" "github.com/ethereum/go-ethereum/rlp" ) 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 } // NewProtocolManager returns a new ethereum sub protocol manager. The Ethereum sub protocol manages peers capable // with the ethereum network. func NewProtocolManager(protocolVersion, networkId int, txpool txPool, chainman *core.ChainManager, downloader *downloader.Downloader) *ProtocolManager { manager := &ProtocolManager{ txpool: txpool, chainman: chainman, downloader: downloader, peers: make(map[string]*peer), } 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) err := manager.handle(peer) glog.V(logger.Detail).Infof("[%s]: %v\n", peer.id, err) return err }, } return manager } 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.td, p.currentHash, 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) return p.sendBlockHashes(hashes) case BlockHashesMsg: msgStream := rlp.NewStream(msg.Payload) var hashes []common.Hash if err := msgStream.Decode(&hashes); err != nil { break } self.downloader.HashCh <- hashes case GetBlocksMsg: msgStream := rlp.NewStream(msg.Payload) if _, err := msgStream.List(); err != nil { return err } var blocks []*types.Block 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: msgStream := rlp.NewStream(msg.Payload) var blocks []*types.Block 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 detirmine // 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) && self.chainman.Td().Cmp(request.TD) > 0 { 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. // NOTE we can reduce chatter by dropping blocks with Td < currentTd 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 { self.downloader.AddBlock(p.id, request.Block, request.TD) } 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") }