package blockchain
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import (
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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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cmn "github.com/tendermint/tendermint/libs/common"
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flow "github.com/tendermint/tendermint/libs/flowrate"
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"github.com/tendermint/tendermint/libs/log"
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"github.com/tendermint/tendermint/p2p"
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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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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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type BlockPool struct {
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cmn.BaseService
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startTime time.Time
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mtx sync.Mutex
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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[p2p.ID]*bpPeer
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maxPeerHeight int64
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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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}
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func NewBlockPool(start int64, requestsCh chan<- BlockRequest, errorsCh chan<- peerError) *BlockPool {
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bp := &BlockPool{
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peers: make(map[p2p.ID]*bpPeer),
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requesters: make(map[int64]*bpRequester),
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height: start,
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numPending: 0,
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requestsCh: requestsCh,
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errorsCh: errorsCh,
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}
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bp.BaseService = *cmn.NewBaseService(nil, "BlockPool", bp)
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return bp
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}
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func (pool *BlockPool) OnStart() error {
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go pool.makeRequestersRoutine()
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pool.startTime = time.Now()
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return nil
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}
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func (pool *BlockPool) OnStop() {}
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// Run spawns requesters as needed.
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func (pool *BlockPool) makeRequestersRoutine() {
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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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if 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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} else if 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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} else {
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// request for more blocks.
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pool.makeNextRequester()
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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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if !peer.didTimeout && peer.numPending > 0 {
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curRate := peer.recvMonitor.Status().CurRate
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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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func (pool *BlockPool) GetStatus() (height int64, numPending int32, lenRequesters int) {
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pool.mtx.Lock()
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defer pool.mtx.Unlock()
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return pool.height, atomic.LoadInt32(&pool.numPending), len(pool.requesters)
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}
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// TODO: relax conditions, prevent abuse.
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func (pool *BlockPool) IsCaughtUp() bool {
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pool.mtx.Lock()
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defer pool.mtx.Unlock()
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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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pool.Logger.Debug("Blockpool has no peers")
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return false
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}
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// Some conditions to determine if we're caught up.
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// Ensures we've either received a block or waited some amount of time,
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// and that we're synced to the highest known height. Note we use maxPeerHeight - 1
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// because to sync block H requires block H+1 to verify the LastCommit.
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receivedBlockOrTimedOut := pool.height > 0 || time.Since(pool.startTime) > 5*time.Second
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ourChainIsLongestAmongPeers := pool.maxPeerHeight == 0 || pool.height >= (pool.maxPeerHeight-1)
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isCaughtUp := receivedBlockOrTimedOut && ourChainIsLongestAmongPeers
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return isCaughtUp
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}
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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.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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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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// Pop 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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/* The block can disappear at any time, due to removePeer().
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if r := pool.requesters[pool.height]; r == nil || r.block == nil {
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PanicSanity("PopRequest() requires a valid block")
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}
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*/
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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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} 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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// 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) p2p.ID {
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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 != p2p.ID("") {
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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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// TODO: ensure that blocks come in order for each peer.
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func (pool *BlockPool) AddBlock(peerID p2p.ID, 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.Info("peer sent us a block we didn't expect", "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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pool.Logger.Info("invalid peer", "peer", peerID, "blockHeight", block.Height)
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pool.sendError(errors.New("invalid peer"), peerID)
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}
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}
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// MaxPeerHeight returns the highest height reported by a peer.
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func (pool *BlockPool) MaxPeerHeight() int64 {
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pool.mtx.Lock()
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defer pool.mtx.Unlock()
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return pool.maxPeerHeight
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}
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// Sets the peer's alleged blockchain height.
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func (pool *BlockPool) SetPeerHeight(peerID p2p.ID, 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.height = height
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} else {
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peer = newBPPeer(pool, peerID, height)
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peer.setLogger(pool.Logger.With("peer", peerID))
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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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func (pool *BlockPool) RemovePeer(peerID p2p.ID) {
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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 p2p.ID) {
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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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delete(pool.peers, peerID)
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}
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// Pick an available peer with at least the given minHeight.
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// If no peers are available, returns nil.
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func (pool *BlockPool) pickIncrAvailablePeer(minHeight 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 peer.height < minHeight {
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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() {
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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, 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()
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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 p2p.ID) {
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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 p2p.ID) {
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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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// unused by tendermint; left for debugging purposes
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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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//-------------------------------------
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type bpPeer struct {
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pool *BlockPool
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id p2p.ID
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recvMonitor *flow.Monitor
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height int64
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numPending int32
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timeout *time.Timer
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didTimeout bool
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logger log.Logger
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}
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func newBPPeer(pool *BlockPool, peerID p2p.ID, height int64) *bpPeer {
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peer := &bpPeer{
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pool: pool,
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id: peerID,
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height: height,
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numPending: 0,
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logger: log.NewNopLogger(),
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}
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return peer
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}
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func (peer *bpPeer) setLogger(l log.Logger) {
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peer.logger = l
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}
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func (peer *bpPeer) resetMonitor() {
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peer.recvMonitor = flow.New(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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|
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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 {
|
|
cmn.BaseService
|
|
pool *BlockPool
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height int64
|
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gotBlockCh chan struct{}
|
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redoCh chan p2p.ID //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 p2p.ID
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block *types.Block
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}
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|
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func newBPRequester(pool *BlockPool, height int64) *bpRequester {
|
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bpr := &bpRequester{
|
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pool: pool,
|
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height: height,
|
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gotBlockCh: make(chan struct{}, 1),
|
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redoCh: make(chan p2p.ID, 1),
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|
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peerID: "",
|
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block: nil,
|
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}
|
|
bpr.BaseService = *cmn.NewBaseService(nil, "bpRequester", bpr)
|
|
return bpr
|
|
}
|
|
|
|
func (bpr *bpRequester) OnStart() error {
|
|
go bpr.requestRoutine()
|
|
return nil
|
|
}
|
|
|
|
// Returns true if the peer matches and block doesn't already exist.
|
|
func (bpr *bpRequester) setBlock(block *types.Block, peerID p2p.ID) 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() p2p.ID {
|
|
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 p2p.ID) {
|
|
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() {
|
|
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 {
|
|
//log.Info("No peers available", "height", height)
|
|
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 <-bpr.pool.Quit():
|
|
bpr.Stop()
|
|
return
|
|
case <-bpr.Quit():
|
|
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
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
//-------------------------------------
|
|
|
|
type BlockRequest struct {
|
|
Height int64
|
|
PeerID p2p.ID
|
|
}
|