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package blockchain
import (
"bytes"
"errors"
"reflect"
"time"
wire "github.com/tendermint/go-wire"
"github.com/tendermint/tendermint/p2p"
"github.com/tendermint/tendermint/proxy"
sm "github.com/tendermint/tendermint/state"
"github.com/tendermint/tendermint/types"
cmn "github.com/tendermint/tmlibs/common"
)
const (
// BlockchainChannel is a channel for blocks and status updates (`BlockStore` height)
BlockchainChannel = byte(0x40)
defaultChannelCapacity = 100
trySyncIntervalMS = 100
// 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
)
type consensusReactor interface {
// for when we switch from blockchain reactor and fast sync to
// the consensus machine
SwitchToConsensus(*sm.State)
}
// BlockchainReactor handles long-term catchup syncing.
type BlockchainReactor struct {
p2p.BaseReactor
state *sm.State
proxyAppConn proxy.AppConnConsensus // same as consensus.proxyAppConn
store *BlockStore
pool *BlockPool
fastSync bool
requestsCh chan BlockRequest
timeoutsCh chan string
evsw types.EventSwitch
}
// NewBlockchainReactor returns new reactor instance.
func NewBlockchainReactor(state *sm.State, proxyAppConn proxy.AppConnConsensus, store *BlockStore, fastSync bool) *BlockchainReactor {
if state.LastBlockHeight == store.Height()-1 {
store.height-- // XXX HACK, make this better
}
if state.LastBlockHeight != store.Height() {
cmn.PanicSanity(cmn.Fmt("state (%v) and store (%v) height mismatch", state.LastBlockHeight, store.Height()))
}
requestsCh := make(chan BlockRequest, defaultChannelCapacity)
timeoutsCh := make(chan string, defaultChannelCapacity)
pool := NewBlockPool(
store.Height()+1,
requestsCh,
timeoutsCh,
)
bcR := &BlockchainReactor{
state: state,
proxyAppConn: proxyAppConn,
store: store,
pool: pool,
fastSync: fastSync,
requestsCh: requestsCh,
timeoutsCh: timeoutsCh,
}
bcR.BaseReactor = *p2p.NewBaseReactor("BlockchainReactor", bcR)
return bcR
}
// OnStart implements BaseService
func (bcR *BlockchainReactor) OnStart() error {
bcR.BaseReactor.OnStart()
if bcR.fastSync {
_, err := bcR.pool.Start()
if err != nil {
return err
}
go bcR.poolRoutine()
}
return nil
}
// OnStop implements BaseService
func (bcR *BlockchainReactor) OnStop() {
bcR.BaseReactor.OnStop()
bcR.pool.Stop()
}
// GetChannels implements Reactor
func (bcR *BlockchainReactor) GetChannels() []*p2p.ChannelDescriptor {
return []*p2p.ChannelDescriptor{
&p2p.ChannelDescriptor{
ID: BlockchainChannel,
Priority: 5,
SendQueueCapacity: 100,
},
}
}
// AddPeer implements Reactor by sending our state to peer.
func (bcR *BlockchainReactor) AddPeer(peer p2p.Peer) {
if !peer.Send(BlockchainChannel, struct{ BlockchainMessage }{&bcStatusResponseMessage{bcR.store.Height()}}) {
// doing nothing, will try later in `poolRoutine`
}
}
// RemovePeer implements Reactor by removing peer from the pool.
func (bcR *BlockchainReactor) RemovePeer(peer p2p.Peer, reason interface{}) {
bcR.pool.RemovePeer(peer.Key())
}
// 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 {
msg := &bcBlockResponseMessage{Block: block}
return src.TrySend(BlockchainChannel, struct{ BlockchainMessage }{msg})
}
bcR.Logger.Info("Peer asking for a block we don't have", "src", src, "height", msg.Height)
return src.TrySend(BlockchainChannel, struct{ BlockchainMessage }{
&bcNoBlockResponseMessage{Height: msg.Height},
})
}
// Receive implements Reactor by handling 4 types of messages (look below).
func (bcR *BlockchainReactor) Receive(chID byte, src p2p.Peer, msgBytes []byte) {
_, msg, err := DecodeMessage(msgBytes, bcR.maxMsgSize())
if err != nil {
bcR.Logger.Error("Error decoding message", "err", err)
return
}
bcR.Logger.Debug("Receive", "src", src, "chID", chID, "msg", msg)
// TODO: improve logic to satisfy megacheck
switch msg := msg.(type) {
case *bcBlockRequestMessage:
if queued := bcR.respondToPeer(msg, src); !queued {
// Unfortunately not queued since the queue is full.
}
case *bcBlockResponseMessage:
// Got a block.
bcR.pool.AddBlock(src.Key(), msg.Block, len(msgBytes))
case *bcStatusRequestMessage:
// Send peer our state.
queued := src.TrySend(BlockchainChannel, struct{ BlockchainMessage }{&bcStatusResponseMessage{bcR.store.Height()}})
if !queued {
// sorry
}
case *bcStatusResponseMessage:
// Got a peer status. Unverified.
bcR.pool.SetPeerHeight(src.Key(), msg.Height)
default:
bcR.Logger.Error(cmn.Fmt("Unknown message type %v", reflect.TypeOf(msg)))
}
}
// maxMsgSize returns the maximum allowable size of a
// message on the blockchain reactor.
func (bcR *BlockchainReactor) maxMsgSize() int {
return bcR.state.Params.BlockSizeParams.MaxBytes + 2
}
// Handle messages from the poolReactor telling the reactor what to do.
// NOTE: Don't sleep in the FOR_LOOP or otherwise slow it down!
// (Except for the SYNC_LOOP, which is the primary purpose and must be synchronous.)
func (bcR *BlockchainReactor) poolRoutine() {
trySyncTicker := time.NewTicker(trySyncIntervalMS * time.Millisecond)
statusUpdateTicker := time.NewTicker(statusUpdateIntervalSeconds * time.Second)
switchToConsensusTicker := time.NewTicker(switchToConsensusIntervalSeconds * time.Second)
chainID := bcR.state.ChainID
FOR_LOOP:
for {
select {
case request := <-bcR.requestsCh: // chan BlockRequest
peer := bcR.Switch.Peers().Get(request.PeerID)
if peer == nil {
continue FOR_LOOP // Peer has since been disconnected.
}
msg := &bcBlockRequestMessage{request.Height}
queued := peer.TrySend(BlockchainChannel, struct{ BlockchainMessage }{msg})
if !queued {
// We couldn't make the request, send-queue full.
// The pool handles timeouts, just let it go.
continue FOR_LOOP
}
case peerID := <-bcR.timeoutsCh: // chan string
// Peer timed out.
peer := bcR.Switch.Peers().Get(peerID)
if peer != nil {
bcR.Switch.StopPeerForError(peer, errors.New("BlockchainReactor Timeout"))
}
case <-statusUpdateTicker.C:
// ask for status updates
go bcR.BroadcastStatusRequest()
case <-switchToConsensusTicker.C:
height, numPending, _ := bcR.pool.GetStatus()
outbound, inbound, _ := bcR.Switch.NumPeers()
bcR.Logger.Info("Consensus ticker", "numPending", numPending, "total", len(bcR.pool.requesters),
"outbound", outbound, "inbound", inbound)
if bcR.pool.IsCaughtUp() {
bcR.Logger.Info("Time to switch to consensus reactor!", "height", height)
bcR.pool.Stop()
conR := bcR.Switch.Reactor("CONSENSUS").(consensusReactor)
conR.SwitchToConsensus(bcR.state)
break FOR_LOOP
}
case <-trySyncTicker.C: // chan time
// This loop can be slow as long as it's doing syncing work.
SYNC_LOOP:
for i := 0; i < 10; i++ {
// 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.
break SYNC_LOOP
}
firstParts := first.MakePartSet(bcR.state.Params.BlockPartSizeBytes)
firstPartsHeader := firstParts.Header()
// 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 := bcR.state.Validators.VerifyCommit(
chainID, types.BlockID{first.Hash(), firstPartsHeader}, first.Height, second.LastCommit)
if err != nil {
bcR.Logger.Error("Error in validation", "err", err)
bcR.pool.RedoRequest(first.Height)
break SYNC_LOOP
} else {
bcR.pool.PopRequest()
bcR.store.SaveBlock(first, firstParts, second.LastCommit)
// TODO: should we be firing events? need to fire NewBlock events manually ...
// NOTE: we could improve performance if we
// didn't make the app commit to disk every block
// ... but we would need a way to get the hash without it persisting
err := bcR.state.ApplyBlock(bcR.evsw, bcR.proxyAppConn, first, firstPartsHeader, types.MockMempool{})
if err != nil {
// TODO This is bad, are we zombie?
cmn.PanicQ(cmn.Fmt("Failed to process committed block (%d:%X): %v", first.Height, first.Hash(), err))
}
}
}
continue FOR_LOOP
case <-bcR.Quit:
break FOR_LOOP
}
}
}
// BroadcastStatusRequest broadcasts `BlockStore` height.
func (bcR *BlockchainReactor) BroadcastStatusRequest() error {
bcR.Switch.Broadcast(BlockchainChannel, struct{ BlockchainMessage }{&bcStatusRequestMessage{bcR.store.Height()}})
return nil
}
// SetEventSwitch implements events.Eventable
func (bcR *BlockchainReactor) SetEventSwitch(evsw types.EventSwitch) {
bcR.evsw = evsw
}
//-----------------------------------------------------------------------------
// Messages
const (
msgTypeBlockRequest = byte(0x10)
msgTypeBlockResponse = byte(0x11)
msgTypeNoBlockResponse = byte(0x12)
msgTypeStatusResponse = byte(0x20)
msgTypeStatusRequest = byte(0x21)
)
// BlockchainMessage is a generic message for this reactor.
type BlockchainMessage interface{}
var _ = wire.RegisterInterface(
struct{ BlockchainMessage }{},
wire.ConcreteType{&bcBlockRequestMessage{}, msgTypeBlockRequest},
wire.ConcreteType{&bcBlockResponseMessage{}, msgTypeBlockResponse},
wire.ConcreteType{&bcNoBlockResponseMessage{}, msgTypeNoBlockResponse},
wire.ConcreteType{&bcStatusResponseMessage{}, msgTypeStatusResponse},
wire.ConcreteType{&bcStatusRequestMessage{}, msgTypeStatusRequest},
)
// DecodeMessage decodes BlockchainMessage.
// TODO: ensure that bz is completely read.
func DecodeMessage(bz []byte, maxSize int) (msgType byte, msg BlockchainMessage, err error) {
msgType = bz[0]
n := int(0)
r := bytes.NewReader(bz)
msg = wire.ReadBinary(struct{ BlockchainMessage }{}, r, maxSize, &n, &err).(struct{ BlockchainMessage }).BlockchainMessage
if err != nil && n != len(bz) {
err = errors.New("DecodeMessage() had bytes left over")
}
return
}
//-------------------------------------
type bcBlockRequestMessage struct {
Height int
}
func (m *bcBlockRequestMessage) String() string {
return cmn.Fmt("[bcBlockRequestMessage %v]", m.Height)
}
type bcNoBlockResponseMessage struct {
Height int
}
func (brm *bcNoBlockResponseMessage) String() string {
return cmn.Fmt("[bcNoBlockResponseMessage %d]", brm.Height)
}
//-------------------------------------
// NOTE: keep up-to-date with maxBlockchainResponseSize
type bcBlockResponseMessage struct {
Block *types.Block
}
func (m *bcBlockResponseMessage) String() string {
return cmn.Fmt("[bcBlockResponseMessage %v]", m.Block.Height)
}
//-------------------------------------
type bcStatusRequestMessage struct {
Height int
}
func (m *bcStatusRequestMessage) String() string {
return cmn.Fmt("[bcStatusRequestMessage %v]", m.Height)
}
//-------------------------------------
type bcStatusResponseMessage struct {
Height int
}
func (m *bcStatusResponseMessage) String() string {
return cmn.Fmt("[bcStatusResponseMessage %v]", m.Height)
}