package blockchain import ( "errors" "fmt" "reflect" "time" amino "github.com/tendermint/go-amino" cmn "github.com/tendermint/tendermint/libs/common" "github.com/tendermint/tendermint/libs/log" "github.com/tendermint/tendermint/p2p" sm "github.com/tendermint/tendermint/state" "github.com/tendermint/tendermint/types" ) const ( // BlockchainChannel is a channel for blocks and status updates (`BlockStore` height) BlockchainChannel = byte(0x40) trySyncIntervalMS = 10 // stop syncing when last block's time is // within this much of the system time. // stopSyncingDurationMinutes = 10 // ask for best height every 10s statusUpdateIntervalSeconds = 10 // check if we should switch to consensus reactor switchToConsensusIntervalSeconds = 1 // NOTE: keep up to date with bcBlockResponseMessage bcBlockResponseMessagePrefixSize = 4 bcBlockResponseMessageFieldKeySize = 1 maxMsgSize = types.MaxBlockSizeBytes + bcBlockResponseMessagePrefixSize + bcBlockResponseMessageFieldKeySize ) type consensusReactor interface { // for when we switch from blockchain reactor and fast sync to // the consensus machine SwitchToConsensus(sm.State, int) } type peerError struct { err error peerID p2p.ID } func (e peerError) Error() string { return fmt.Sprintf("error with peer %v: %s", e.peerID, e.err.Error()) } // BlockchainReactor handles long-term catchup syncing. type BlockchainReactor struct { p2p.BaseReactor // immutable initialState sm.State blockExec *sm.BlockExecutor store *BlockStore pool *BlockPool fastSync bool requestsCh <-chan BlockRequest errorsCh <-chan peerError } // NewBlockchainReactor returns new reactor instance. func NewBlockchainReactor(state sm.State, blockExec *sm.BlockExecutor, store *BlockStore, fastSync bool) *BlockchainReactor { if state.LastBlockHeight != store.Height() { panic(fmt.Sprintf("state (%v) and store (%v) height mismatch", state.LastBlockHeight, store.Height())) } requestsCh := make(chan BlockRequest, maxTotalRequesters) const capacity = 1000 // must be bigger than peers count errorsCh := make(chan peerError, capacity) // so we don't block in #Receive#pool.AddBlock pool := NewBlockPool( store.Height()+1, requestsCh, errorsCh, ) bcR := &BlockchainReactor{ initialState: state, blockExec: blockExec, store: store, pool: pool, fastSync: fastSync, requestsCh: requestsCh, errorsCh: errorsCh, } bcR.BaseReactor = *p2p.NewBaseReactor("BlockchainReactor", bcR) return bcR } // SetLogger implements cmn.Service by setting the logger on reactor and pool. func (bcR *BlockchainReactor) SetLogger(l log.Logger) { bcR.BaseService.Logger = l bcR.pool.Logger = l } // OnStart implements cmn.Service. func (bcR *BlockchainReactor) OnStart() error { if bcR.fastSync { err := bcR.pool.Start() if err != nil { return err } go bcR.poolRoutine() } return nil } // OnStop implements cmn.Service. func (bcR *BlockchainReactor) OnStop() { bcR.pool.Stop() } // GetChannels implements Reactor func (bcR *BlockchainReactor) GetChannels() []*p2p.ChannelDescriptor { return []*p2p.ChannelDescriptor{ { ID: BlockchainChannel, Priority: 10, SendQueueCapacity: 1000, RecvBufferCapacity: 50 * 4096, RecvMessageCapacity: maxMsgSize, }, } } // AddPeer implements Reactor by sending our state to peer. func (bcR *BlockchainReactor) AddPeer(peer p2p.Peer) { msgBytes := cdc.MustMarshalBinaryBare(&bcStatusResponseMessage{bcR.store.Height()}) if !peer.Send(BlockchainChannel, msgBytes) { // doing nothing, will try later in `poolRoutine` } // peer is added to the pool once we receive the first // bcStatusResponseMessage from the peer and call pool.SetPeerHeight } // RemovePeer implements Reactor by removing peer from the pool. func (bcR *BlockchainReactor) RemovePeer(peer p2p.Peer, reason interface{}) { bcR.pool.RemovePeer(peer.ID()) } // respondToPeer loads a block and sends it to the requesting peer, // if we have it. Otherwise, we'll respond saying we don't have it. // According to the Tendermint spec, if all nodes are honest, // no node should be requesting for a block that's non-existent. func (bcR *BlockchainReactor) respondToPeer(msg *bcBlockRequestMessage, src p2p.Peer) (queued bool) { block := bcR.store.LoadBlock(msg.Height) if block != nil { msgBytes := cdc.MustMarshalBinaryBare(&bcBlockResponseMessage{Block: block}) return src.TrySend(BlockchainChannel, msgBytes) } bcR.Logger.Info("Peer asking for a block we don't have", "src", src, "height", msg.Height) msgBytes := cdc.MustMarshalBinaryBare(&bcNoBlockResponseMessage{Height: msg.Height}) return src.TrySend(BlockchainChannel, msgBytes) } // Receive implements Reactor by handling 4 types of messages (look below). func (bcR *BlockchainReactor) Receive(chID byte, src p2p.Peer, msgBytes []byte) { msg, err := decodeMsg(msgBytes) if err != nil { bcR.Logger.Error("Error decoding message", "src", src, "chId", chID, "msg", msg, "err", err, "bytes", msgBytes) bcR.Switch.StopPeerForError(src, err) return } if err = msg.ValidateBasic(); err != nil { bcR.Logger.Error("Peer sent us invalid msg", "peer", src, "msg", msg, "err", err) bcR.Switch.StopPeerForError(src, err) return } bcR.Logger.Debug("Receive", "src", src, "chID", chID, "msg", msg) switch msg := msg.(type) { case *bcBlockRequestMessage: if queued := bcR.respondToPeer(msg, src); !queued { // Unfortunately not queued since the queue is full. } case *bcBlockResponseMessage: bcR.pool.AddBlock(src.ID(), msg.Block, len(msgBytes)) case *bcStatusRequestMessage: // Send peer our state. msgBytes := cdc.MustMarshalBinaryBare(&bcStatusResponseMessage{bcR.store.Height()}) queued := src.TrySend(BlockchainChannel, msgBytes) if !queued { // sorry } case *bcStatusResponseMessage: // Got a peer status. Unverified. bcR.pool.SetPeerHeight(src.ID(), msg.Height) default: bcR.Logger.Error(fmt.Sprintf("Unknown message type %v", reflect.TypeOf(msg))) } } // Handle messages from the poolReactor telling the reactor what to do. // NOTE: Don't sleep in the FOR_LOOP or otherwise slow it down! func (bcR *BlockchainReactor) poolRoutine() { trySyncTicker := time.NewTicker(trySyncIntervalMS * time.Millisecond) statusUpdateTicker := time.NewTicker(statusUpdateIntervalSeconds * time.Second) switchToConsensusTicker := time.NewTicker(switchToConsensusIntervalSeconds * time.Second) blocksSynced := 0 chainID := bcR.initialState.ChainID state := bcR.initialState lastHundred := time.Now() lastRate := 0.0 didProcessCh := make(chan struct{}, 1) FOR_LOOP: for { select { case request := <-bcR.requestsCh: peer := bcR.Switch.Peers().Get(request.PeerID) if peer == nil { continue FOR_LOOP // Peer has since been disconnected. } msgBytes := cdc.MustMarshalBinaryBare(&bcBlockRequestMessage{request.Height}) queued := peer.TrySend(BlockchainChannel, msgBytes) if !queued { // We couldn't make the request, send-queue full. // The pool handles timeouts, just let it go. continue FOR_LOOP } case err := <-bcR.errorsCh: peer := bcR.Switch.Peers().Get(err.peerID) if peer != nil { bcR.Switch.StopPeerForError(peer, err) } case <-statusUpdateTicker.C: // ask for status updates go bcR.BroadcastStatusRequest() // nolint: errcheck case <-switchToConsensusTicker.C: height, numPending, lenRequesters := bcR.pool.GetStatus() outbound, inbound, _ := bcR.Switch.NumPeers() bcR.Logger.Debug("Consensus ticker", "numPending", numPending, "total", lenRequesters, "outbound", outbound, "inbound", inbound) if bcR.pool.IsCaughtUp() { bcR.Logger.Info("Time to switch to consensus reactor!", "height", height) bcR.pool.Stop() conR, ok := bcR.Switch.Reactor("CONSENSUS").(consensusReactor) if ok { conR.SwitchToConsensus(state, blocksSynced) } else { // should only happen during testing } break FOR_LOOP } case <-trySyncTicker.C: // chan time select { case didProcessCh <- struct{}{}: default: } case <-didProcessCh: // NOTE: It is a subtle mistake to process more than a single block // at a time (e.g. 10) here, because we only TrySend 1 request per // loop. The ratio mismatch can result in starving of blocks, a // sudden burst of requests and responses, and repeat. // Consequently, it is better to split these routines rather than // coupling them as it's written here. TODO uncouple from request // routine. // See if there are any blocks to sync. first, second := bcR.pool.PeekTwoBlocks() //bcR.Logger.Info("TrySync peeked", "first", first, "second", second) if first == nil || second == nil { // We need both to sync the first block. continue FOR_LOOP } else { // Try again quickly next loop. didProcessCh <- struct{}{} } firstParts := first.MakePartSet(types.BlockPartSizeBytes) firstPartsHeader := firstParts.Header() firstID := types.BlockID{first.Hash(), firstPartsHeader} // Finally, verify the first block using the second's commit // NOTE: we can probably make this more efficient, but note that calling // first.Hash() doesn't verify the tx contents, so MakePartSet() is // currently necessary. err := state.Validators.VerifyCommit( chainID, firstID, first.Height, second.LastCommit) if err != nil { bcR.Logger.Error("Error in validation", "err", err) peerID := bcR.pool.RedoRequest(first.Height) peer := bcR.Switch.Peers().Get(peerID) if peer != nil { // NOTE: we've already removed the peer's request, but we // still need to clean up the rest. bcR.Switch.StopPeerForError(peer, fmt.Errorf("BlockchainReactor validation error: %v", err)) } peerID2 := bcR.pool.RedoRequest(second.Height) peer2 := bcR.Switch.Peers().Get(peerID2) if peer2 != nil && peer2 != peer { // NOTE: we've already removed the peer's request, but we // still need to clean up the rest. bcR.Switch.StopPeerForError(peer2, fmt.Errorf("BlockchainReactor validation error: %v", err)) } continue FOR_LOOP } else { bcR.pool.PopRequest() // TODO: batch saves so we dont persist to disk every block bcR.store.SaveBlock(first, firstParts, second.LastCommit) // TODO: same thing for app - but we would need a way to // get the hash without persisting the state var err error state, err = bcR.blockExec.ApplyBlock(state, firstID, first) if err != nil { // TODO This is bad, are we zombie? cmn.PanicQ(fmt.Sprintf("Failed to process committed block (%d:%X): %v", first.Height, first.Hash(), err)) } blocksSynced++ if blocksSynced%100 == 0 { lastRate = 0.9*lastRate + 0.1*(100/time.Since(lastHundred).Seconds()) bcR.Logger.Info("Fast Sync Rate", "height", bcR.pool.height, "max_peer_height", bcR.pool.MaxPeerHeight(), "blocks/s", lastRate) lastHundred = time.Now() } } continue FOR_LOOP case <-bcR.Quit(): break FOR_LOOP } } } // BroadcastStatusRequest broadcasts `BlockStore` height. func (bcR *BlockchainReactor) BroadcastStatusRequest() error { msgBytes := cdc.MustMarshalBinaryBare(&bcStatusRequestMessage{bcR.store.Height()}) bcR.Switch.Broadcast(BlockchainChannel, msgBytes) return nil } //----------------------------------------------------------------------------- // Messages // BlockchainMessage is a generic message for this reactor. type BlockchainMessage interface { ValidateBasic() error } func RegisterBlockchainMessages(cdc *amino.Codec) { cdc.RegisterInterface((*BlockchainMessage)(nil), nil) cdc.RegisterConcrete(&bcBlockRequestMessage{}, "tendermint/blockchain/BlockRequest", nil) cdc.RegisterConcrete(&bcBlockResponseMessage{}, "tendermint/blockchain/BlockResponse", nil) cdc.RegisterConcrete(&bcNoBlockResponseMessage{}, "tendermint/blockchain/NoBlockResponse", nil) cdc.RegisterConcrete(&bcStatusResponseMessage{}, "tendermint/blockchain/StatusResponse", nil) cdc.RegisterConcrete(&bcStatusRequestMessage{}, "tendermint/blockchain/StatusRequest", nil) } func decodeMsg(bz []byte) (msg BlockchainMessage, err error) { if len(bz) > maxMsgSize { return msg, fmt.Errorf("Msg exceeds max size (%d > %d)", len(bz), maxMsgSize) } err = cdc.UnmarshalBinaryBare(bz, &msg) return } //------------------------------------- type bcBlockRequestMessage struct { Height int64 } // ValidateBasic performs basic validation. func (m *bcBlockRequestMessage) ValidateBasic() error { if m.Height < 0 { return errors.New("Negative Height") } return nil } func (m *bcBlockRequestMessage) String() string { return fmt.Sprintf("[bcBlockRequestMessage %v]", m.Height) } type bcNoBlockResponseMessage struct { Height int64 } // ValidateBasic performs basic validation. func (m *bcNoBlockResponseMessage) ValidateBasic() error { if m.Height < 0 { return errors.New("Negative Height") } return nil } func (brm *bcNoBlockResponseMessage) String() string { return fmt.Sprintf("[bcNoBlockResponseMessage %d]", brm.Height) } //------------------------------------- type bcBlockResponseMessage struct { Block *types.Block } // ValidateBasic performs basic validation. func (m *bcBlockResponseMessage) ValidateBasic() error { return m.Block.ValidateBasic() } func (m *bcBlockResponseMessage) String() string { return fmt.Sprintf("[bcBlockResponseMessage %v]", m.Block.Height) } //------------------------------------- type bcStatusRequestMessage struct { Height int64 } // ValidateBasic performs basic validation. func (m *bcStatusRequestMessage) ValidateBasic() error { if m.Height < 0 { return errors.New("Negative Height") } return nil } func (m *bcStatusRequestMessage) String() string { return fmt.Sprintf("[bcStatusRequestMessage %v]", m.Height) } //------------------------------------- type bcStatusResponseMessage struct { Height int64 } // ValidateBasic performs basic validation. func (m *bcStatusResponseMessage) ValidateBasic() error { if m.Height < 0 { return errors.New("Negative Height") } return nil } func (m *bcStatusResponseMessage) String() string { return fmt.Sprintf("[bcStatusResponseMessage %v]", m.Height) }