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674 lines
16 KiB
674 lines
16 KiB
package blocksync
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import (
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"context"
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"errors"
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"fmt"
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"math"
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"sync"
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"sync/atomic"
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"time"
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"github.com/tendermint/tendermint/internal/libs/flowrate"
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"github.com/tendermint/tendermint/libs/log"
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"github.com/tendermint/tendermint/libs/service"
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"github.com/tendermint/tendermint/types"
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)
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/*
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eg, L = latency = 0.1s
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P = num peers = 10
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FN = num full nodes
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BS = 1kB block size
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CB = 1 Mbit/s = 128 kB/s
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CB/P = 12.8 kB
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B/S = CB/P/BS = 12.8 blocks/s
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12.8 * 0.1 = 1.28 blocks on conn
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*/
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const (
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requestIntervalMS = 2
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maxTotalRequesters = 600
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maxPeerErrBuffer = 1000
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maxPendingRequests = maxTotalRequesters
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maxPendingRequestsPerPeer = 20
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// Minimum recv rate to ensure we're receiving blocks from a peer fast
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// enough. If a peer is not sending us data at at least that rate, we
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// consider them to have timedout and we disconnect.
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//
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// Assuming a DSL connection (not a good choice) 128 Kbps (upload) ~ 15 KB/s,
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// sending data across atlantic ~ 7.5 KB/s.
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minRecvRate = 7680
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// Maximum difference between current and new block's height.
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maxDiffBetweenCurrentAndReceivedBlockHeight = 100
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)
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var peerTimeout = 15 * time.Second // not const so we can override with tests
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/*
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Peers self report their heights when we join the block pool.
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Starting from our latest pool.height, we request blocks
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in sequence from peers that reported higher heights than ours.
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Every so often we ask peers what height they're on so we can keep going.
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Requests are continuously made for blocks of higher heights until
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the limit is reached. If most of the requests have no available peers, and we
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are not at peer limits, we can probably switch to consensus reactor
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*/
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// BlockRequest stores a block request identified by the block Height and the
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// PeerID responsible for delivering the block.
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type BlockRequest struct {
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Height int64
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PeerID types.NodeID
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}
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// BlockPool keeps track of the block sync peers, block requests and block responses.
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type BlockPool struct {
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service.BaseService
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logger log.Logger
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lastAdvance time.Time
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mtx sync.RWMutex
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// block requests
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requesters map[int64]*bpRequester
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height int64 // the lowest key in requesters.
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// peers
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peers map[types.NodeID]*bpPeer
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maxPeerHeight int64 // the biggest reported height
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// atomic
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numPending int32 // number of requests pending assignment or block response
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requestsCh chan<- BlockRequest
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errorsCh chan<- peerError
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startHeight int64
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lastHundredBlockTimeStamp time.Time
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lastSyncRate float64
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}
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// NewBlockPool returns a new BlockPool with the height equal to start. Block
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// requests and errors will be sent to requestsCh and errorsCh accordingly.
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func NewBlockPool(
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logger log.Logger,
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start int64,
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requestsCh chan<- BlockRequest,
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errorsCh chan<- peerError,
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) *BlockPool {
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bp := &BlockPool{
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logger: logger,
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peers: make(map[types.NodeID]*bpPeer),
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requesters: make(map[int64]*bpRequester),
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height: start,
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startHeight: start,
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numPending: 0,
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requestsCh: requestsCh,
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errorsCh: errorsCh,
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lastSyncRate: 0,
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}
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bp.BaseService = *service.NewBaseService(logger, "BlockPool", bp)
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return bp
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}
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// OnStart implements service.Service by spawning requesters routine and recording
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// pool's start time.
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func (pool *BlockPool) OnStart(ctx context.Context) error {
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pool.lastAdvance = time.Now()
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pool.lastHundredBlockTimeStamp = pool.lastAdvance
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go pool.makeRequestersRoutine(ctx)
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return nil
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}
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func (*BlockPool) OnStop() {}
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// spawns requesters as needed
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func (pool *BlockPool) makeRequestersRoutine(ctx context.Context) {
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for {
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if !pool.IsRunning() {
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break
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}
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_, numPending, lenRequesters := pool.GetStatus()
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switch {
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case numPending >= maxPendingRequests:
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// sleep for a bit.
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time.Sleep(requestIntervalMS * time.Millisecond)
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// check for timed out peers
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pool.removeTimedoutPeers()
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case lenRequesters >= maxTotalRequesters:
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// sleep for a bit.
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time.Sleep(requestIntervalMS * time.Millisecond)
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// check for timed out peers
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pool.removeTimedoutPeers()
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default:
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// request for more blocks.
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pool.makeNextRequester(ctx)
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}
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}
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}
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func (pool *BlockPool) removeTimedoutPeers() {
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pool.mtx.Lock()
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defer pool.mtx.Unlock()
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for _, peer := range pool.peers {
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// check if peer timed out
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if !peer.didTimeout && peer.numPending > 0 {
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curRate := peer.recvMonitor.CurrentTransferRate()
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// curRate can be 0 on start
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if curRate != 0 && curRate < minRecvRate {
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err := errors.New("peer is not sending us data fast enough")
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pool.sendError(err, peer.id)
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pool.logger.Error("SendTimeout", "peer", peer.id,
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"reason", err,
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"curRate", fmt.Sprintf("%d KB/s", curRate/1024),
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"minRate", fmt.Sprintf("%d KB/s", minRecvRate/1024))
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peer.didTimeout = true
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}
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}
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if peer.didTimeout {
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pool.removePeer(peer.id)
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}
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}
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}
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// GetStatus returns pool's height, numPending requests and the number of
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// requesters.
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func (pool *BlockPool) GetStatus() (height int64, numPending int32, lenRequesters int) {
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pool.mtx.RLock()
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defer pool.mtx.RUnlock()
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return pool.height, atomic.LoadInt32(&pool.numPending), len(pool.requesters)
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}
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// IsCaughtUp returns true if this node is caught up, false - otherwise.
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func (pool *BlockPool) IsCaughtUp() bool {
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pool.mtx.RLock()
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defer pool.mtx.RUnlock()
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// Need at least 1 peer to be considered caught up.
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if len(pool.peers) == 0 {
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return false
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}
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// NOTE: we use maxPeerHeight - 1 because to sync block H requires block H+1
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// to verify the LastCommit.
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return pool.height >= (pool.maxPeerHeight - 1)
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}
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// PeekTwoBlocks returns blocks at pool.height and pool.height+1.
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// We need to see the second block's Commit to validate the first block.
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// So we peek two blocks at a time.
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// The caller will verify the commit.
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func (pool *BlockPool) PeekTwoBlocks() (first *types.Block, second *types.Block) {
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pool.mtx.RLock()
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defer pool.mtx.RUnlock()
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if r := pool.requesters[pool.height]; r != nil {
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first = r.getBlock()
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}
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if r := pool.requesters[pool.height+1]; r != nil {
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second = r.getBlock()
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}
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return
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}
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// PopRequest pops the first block at pool.height.
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// It must have been validated by 'second'.Commit from PeekTwoBlocks().
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func (pool *BlockPool) PopRequest() {
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pool.mtx.Lock()
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defer pool.mtx.Unlock()
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if r := pool.requesters[pool.height]; r != nil {
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r.Stop()
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delete(pool.requesters, pool.height)
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pool.height++
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pool.lastAdvance = time.Now()
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// the lastSyncRate will be updated every 100 blocks, it uses the adaptive filter
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// to smooth the block sync rate and the unit represents the number of blocks per second.
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if (pool.height-pool.startHeight)%100 == 0 {
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newSyncRate := 100 / time.Since(pool.lastHundredBlockTimeStamp).Seconds()
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if pool.lastSyncRate == 0 {
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pool.lastSyncRate = newSyncRate
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} else {
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pool.lastSyncRate = 0.9*pool.lastSyncRate + 0.1*newSyncRate
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}
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pool.lastHundredBlockTimeStamp = time.Now()
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}
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} else {
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panic(fmt.Sprintf("Expected requester to pop, got nothing at height %v", pool.height))
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}
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}
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// RedoRequest invalidates the block at pool.height,
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// Remove the peer and redo request from others.
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// Returns the ID of the removed peer.
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func (pool *BlockPool) RedoRequest(height int64) types.NodeID {
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pool.mtx.Lock()
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defer pool.mtx.Unlock()
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request := pool.requesters[height]
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peerID := request.getPeerID()
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if peerID != types.NodeID("") {
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// RemovePeer will redo all requesters associated with this peer.
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pool.removePeer(peerID)
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}
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return peerID
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}
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// AddBlock validates that the block comes from the peer it was expected from and calls the requester to store it.
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// TODO: ensure that blocks come in order for each peer.
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func (pool *BlockPool) AddBlock(peerID types.NodeID, block *types.Block, blockSize int) {
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pool.mtx.Lock()
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defer pool.mtx.Unlock()
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requester := pool.requesters[block.Height]
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if requester == nil {
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pool.logger.Error("peer sent us a block we didn't expect",
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"peer", peerID, "curHeight", pool.height, "blockHeight", block.Height)
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diff := pool.height - block.Height
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if diff < 0 {
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diff *= -1
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}
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if diff > maxDiffBetweenCurrentAndReceivedBlockHeight {
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pool.sendError(errors.New("peer sent us a block we didn't expect with a height too far ahead/behind"), peerID)
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}
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return
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}
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if requester.setBlock(block, peerID) {
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atomic.AddInt32(&pool.numPending, -1)
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peer := pool.peers[peerID]
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if peer != nil {
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peer.decrPending(blockSize)
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}
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} else {
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err := errors.New("requester is different or block already exists")
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pool.logger.Error(err.Error(), "peer", peerID, "requester", requester.getPeerID(), "blockHeight", block.Height)
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pool.sendError(err, peerID)
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}
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}
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// MaxPeerHeight returns the highest reported height.
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func (pool *BlockPool) MaxPeerHeight() int64 {
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pool.mtx.RLock()
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defer pool.mtx.RUnlock()
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return pool.maxPeerHeight
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}
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// LastAdvance returns the time when the last block was processed (or start
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// time if no blocks were processed).
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func (pool *BlockPool) LastAdvance() time.Time {
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pool.mtx.RLock()
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defer pool.mtx.RUnlock()
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return pool.lastAdvance
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}
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// SetPeerRange sets the peer's alleged blockchain base and height.
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func (pool *BlockPool) SetPeerRange(peerID types.NodeID, base int64, height int64) {
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pool.mtx.Lock()
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defer pool.mtx.Unlock()
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peer := pool.peers[peerID]
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if peer != nil {
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peer.base = base
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peer.height = height
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} else {
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peer = &bpPeer{
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pool: pool,
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id: peerID,
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base: base,
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height: height,
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numPending: 0,
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logger: pool.logger.With("peer", peerID),
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startAt: time.Now(),
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}
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pool.peers[peerID] = peer
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}
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if height > pool.maxPeerHeight {
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pool.maxPeerHeight = height
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}
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}
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// RemovePeer removes the peer with peerID from the pool. If there's no peer
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// with peerID, function is a no-op.
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func (pool *BlockPool) RemovePeer(peerID types.NodeID) {
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pool.mtx.Lock()
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defer pool.mtx.Unlock()
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pool.removePeer(peerID)
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}
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func (pool *BlockPool) removePeer(peerID types.NodeID) {
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for _, requester := range pool.requesters {
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if requester.getPeerID() == peerID {
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requester.redo(peerID)
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}
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}
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peer, ok := pool.peers[peerID]
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if ok {
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if peer.timeout != nil {
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peer.timeout.Stop()
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}
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delete(pool.peers, peerID)
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// Find a new peer with the biggest height and update maxPeerHeight if the
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// peer's height was the biggest.
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if peer.height == pool.maxPeerHeight {
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pool.updateMaxPeerHeight()
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}
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}
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}
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// If no peers are left, maxPeerHeight is set to 0.
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func (pool *BlockPool) updateMaxPeerHeight() {
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var max int64
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for _, peer := range pool.peers {
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if peer.height > max {
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max = peer.height
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}
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}
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pool.maxPeerHeight = max
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}
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// Pick an available peer with the given height available.
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// If no peers are available, returns nil.
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func (pool *BlockPool) pickIncrAvailablePeer(height int64) *bpPeer {
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pool.mtx.Lock()
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defer pool.mtx.Unlock()
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for _, peer := range pool.peers {
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if peer.didTimeout {
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pool.removePeer(peer.id)
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continue
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}
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if peer.numPending >= maxPendingRequestsPerPeer {
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continue
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}
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if height < peer.base || height > peer.height {
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continue
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}
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peer.incrPending()
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return peer
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}
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return nil
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}
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func (pool *BlockPool) makeNextRequester(ctx context.Context) {
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pool.mtx.Lock()
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defer pool.mtx.Unlock()
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nextHeight := pool.height + pool.requestersLen()
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if nextHeight > pool.maxPeerHeight {
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return
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}
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request := newBPRequester(pool.logger, pool, nextHeight)
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pool.requesters[nextHeight] = request
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atomic.AddInt32(&pool.numPending, 1)
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err := request.Start(ctx)
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if err != nil {
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request.logger.Error("error starting request", "err", err)
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}
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}
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func (pool *BlockPool) requestersLen() int64 {
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return int64(len(pool.requesters))
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}
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func (pool *BlockPool) sendRequest(height int64, peerID types.NodeID) {
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if !pool.IsRunning() {
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return
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}
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pool.requestsCh <- BlockRequest{height, peerID}
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}
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func (pool *BlockPool) sendError(err error, peerID types.NodeID) {
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if !pool.IsRunning() {
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return
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}
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pool.errorsCh <- peerError{err, peerID}
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}
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// for debugging purposes
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//nolint:unused
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func (pool *BlockPool) debug() string {
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pool.mtx.Lock()
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defer pool.mtx.Unlock()
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str := ""
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nextHeight := pool.height + pool.requestersLen()
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for h := pool.height; h < nextHeight; h++ {
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if pool.requesters[h] == nil {
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str += fmt.Sprintf("H(%v):X ", h)
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} else {
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str += fmt.Sprintf("H(%v):", h)
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str += fmt.Sprintf("B?(%v) ", pool.requesters[h].block != nil)
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}
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}
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return str
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}
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func (pool *BlockPool) targetSyncBlocks() int64 {
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pool.mtx.RLock()
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defer pool.mtx.RUnlock()
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return pool.maxPeerHeight - pool.startHeight + 1
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}
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func (pool *BlockPool) getLastSyncRate() float64 {
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pool.mtx.RLock()
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defer pool.mtx.RUnlock()
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return pool.lastSyncRate
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}
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//-------------------------------------
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type bpPeer struct {
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didTimeout bool
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numPending int32
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height int64
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base int64
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pool *BlockPool
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id types.NodeID
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recvMonitor *flowrate.Monitor
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timeout *time.Timer
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startAt time.Time
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logger log.Logger
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}
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func (peer *bpPeer) resetMonitor() {
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peer.recvMonitor = flowrate.New(peer.startAt, time.Second, time.Second*40)
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initialValue := float64(minRecvRate) * math.E
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peer.recvMonitor.SetREMA(initialValue)
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}
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func (peer *bpPeer) resetTimeout() {
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if peer.timeout == nil {
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peer.timeout = time.AfterFunc(peerTimeout, peer.onTimeout)
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} else {
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peer.timeout.Reset(peerTimeout)
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}
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}
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func (peer *bpPeer) incrPending() {
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if peer.numPending == 0 {
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peer.resetMonitor()
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peer.resetTimeout()
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}
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peer.numPending++
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}
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func (peer *bpPeer) decrPending(recvSize int) {
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peer.numPending--
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if peer.numPending == 0 {
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peer.timeout.Stop()
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} else {
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peer.recvMonitor.Update(recvSize)
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peer.resetTimeout()
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}
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}
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func (peer *bpPeer) onTimeout() {
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peer.pool.mtx.Lock()
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defer peer.pool.mtx.Unlock()
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err := errors.New("peer did not send us anything")
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peer.pool.sendError(err, peer.id)
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peer.logger.Error("SendTimeout", "reason", err, "timeout", peerTimeout)
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peer.didTimeout = true
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}
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//-------------------------------------
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|
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type bpRequester struct {
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service.BaseService
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logger log.Logger
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pool *BlockPool
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height int64
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gotBlockCh chan struct{}
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redoCh chan types.NodeID // redo may send multitime, add peerId to identify repeat
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|
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mtx sync.Mutex
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peerID types.NodeID
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block *types.Block
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}
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|
|
func newBPRequester(logger log.Logger, pool *BlockPool, height int64) *bpRequester {
|
|
bpr := &bpRequester{
|
|
logger: pool.logger,
|
|
pool: pool,
|
|
height: height,
|
|
gotBlockCh: make(chan struct{}, 1),
|
|
redoCh: make(chan types.NodeID, 1),
|
|
|
|
peerID: "",
|
|
block: nil,
|
|
}
|
|
bpr.BaseService = *service.NewBaseService(logger, "bpRequester", bpr)
|
|
return bpr
|
|
}
|
|
|
|
func (bpr *bpRequester) OnStart(ctx context.Context) error {
|
|
go bpr.requestRoutine(ctx)
|
|
return nil
|
|
}
|
|
|
|
func (*bpRequester) OnStop() {}
|
|
|
|
// Returns true if the peer matches and block doesn't already exist.
|
|
func (bpr *bpRequester) setBlock(block *types.Block, peerID types.NodeID) bool {
|
|
bpr.mtx.Lock()
|
|
if bpr.block != nil || bpr.peerID != peerID {
|
|
bpr.mtx.Unlock()
|
|
return false
|
|
}
|
|
bpr.block = block
|
|
bpr.mtx.Unlock()
|
|
|
|
select {
|
|
case bpr.gotBlockCh <- struct{}{}:
|
|
default:
|
|
}
|
|
return true
|
|
}
|
|
|
|
func (bpr *bpRequester) getBlock() *types.Block {
|
|
bpr.mtx.Lock()
|
|
defer bpr.mtx.Unlock()
|
|
return bpr.block
|
|
}
|
|
|
|
func (bpr *bpRequester) getPeerID() types.NodeID {
|
|
bpr.mtx.Lock()
|
|
defer bpr.mtx.Unlock()
|
|
return bpr.peerID
|
|
}
|
|
|
|
// This is called from the requestRoutine, upon redo().
|
|
func (bpr *bpRequester) reset() {
|
|
bpr.mtx.Lock()
|
|
defer bpr.mtx.Unlock()
|
|
|
|
if bpr.block != nil {
|
|
atomic.AddInt32(&bpr.pool.numPending, 1)
|
|
}
|
|
|
|
bpr.peerID = ""
|
|
bpr.block = nil
|
|
}
|
|
|
|
// Tells bpRequester to pick another peer and try again.
|
|
// NOTE: Nonblocking, and does nothing if another redo
|
|
// was already requested.
|
|
func (bpr *bpRequester) redo(peerID types.NodeID) {
|
|
select {
|
|
case bpr.redoCh <- peerID:
|
|
default:
|
|
}
|
|
}
|
|
|
|
// Responsible for making more requests as necessary
|
|
// Returns only when a block is found (e.g. AddBlock() is called)
|
|
func (bpr *bpRequester) requestRoutine(ctx context.Context) {
|
|
OUTER_LOOP:
|
|
for {
|
|
// Pick a peer to send request to.
|
|
var peer *bpPeer
|
|
PICK_PEER_LOOP:
|
|
for {
|
|
if !bpr.IsRunning() || !bpr.pool.IsRunning() {
|
|
return
|
|
}
|
|
peer = bpr.pool.pickIncrAvailablePeer(bpr.height)
|
|
if peer == nil {
|
|
time.Sleep(requestIntervalMS * time.Millisecond)
|
|
continue PICK_PEER_LOOP
|
|
}
|
|
break PICK_PEER_LOOP
|
|
}
|
|
bpr.mtx.Lock()
|
|
bpr.peerID = peer.id
|
|
bpr.mtx.Unlock()
|
|
|
|
// Send request and wait.
|
|
bpr.pool.sendRequest(bpr.height, peer.id)
|
|
WAIT_LOOP:
|
|
for {
|
|
select {
|
|
case <-ctx.Done():
|
|
return
|
|
case peerID := <-bpr.redoCh:
|
|
if peerID == bpr.peerID {
|
|
bpr.reset()
|
|
continue OUTER_LOOP
|
|
} else {
|
|
continue WAIT_LOOP
|
|
}
|
|
case <-bpr.gotBlockCh:
|
|
// We got a block!
|
|
// Continue the for-loop and wait til Quit.
|
|
continue WAIT_LOOP
|
|
}
|
|
}
|
|
}
|
|
}
|