From 4c1616a746a648c816042f596eb199174a9858f1 Mon Sep 17 00:00:00 2001 From: Determinant Date: Fri, 9 Aug 2019 21:15:05 -0400 Subject: add necessary code base --- eth/sync.go | 216 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 216 insertions(+) create mode 100644 eth/sync.go (limited to 'eth/sync.go') diff --git a/eth/sync.go b/eth/sync.go new file mode 100644 index 0000000..9e180ee --- /dev/null +++ b/eth/sync.go @@ -0,0 +1,216 @@ +// Copyright 2015 The go-ethereum Authors +// This file is part of the go-ethereum library. +// +// The go-ethereum library is free software: you can redistribute it and/or modify +// it under the terms of the GNU Lesser General Public License as published by +// the Free Software Foundation, either version 3 of the License, or +// (at your option) any later version. +// +// The go-ethereum library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU Lesser General Public License for more details. +// +// You should have received a copy of the GNU Lesser General Public License +// along with the go-ethereum library. If not, see . + +package eth + +import ( + "math/rand" + "sync/atomic" + "time" + + "github.com/ethereum/go-ethereum/common" + "github.com/ethereum/go-ethereum/core/types" + "github.com/ethereum/go-ethereum/eth/downloader" + "github.com/ethereum/go-ethereum/log" + "github.com/ethereum/go-ethereum/p2p/enode" +) + +const ( + forceSyncCycle = 10 * time.Second // Time interval to force syncs, even if few peers are available + minDesiredPeerCount = 5 // Amount of peers desired to start syncing + + // This is the target size for the packs of transactions sent by txsyncLoop. + // A pack can get larger than this if a single transactions exceeds this size. + txsyncPackSize = 100 * 1024 +) + +type txsync struct { + p *peer + txs []*types.Transaction +} + +// syncTransactions starts sending all currently pending transactions to the given peer. +func (pm *ProtocolManager) syncTransactions(p *peer) { + var txs types.Transactions + pending, _ := pm.txpool.Pending() + for _, batch := range pending { + txs = append(txs, batch...) + } + if len(txs) == 0 { + return + } + select { + case pm.txsyncCh <- &txsync{p, txs}: + case <-pm.quitSync: + } +} + +// txsyncLoop takes care of the initial transaction sync for each new +// connection. When a new peer appears, we relay all currently pending +// transactions. In order to minimise egress bandwidth usage, we send +// the transactions in small packs to one peer at a time. +func (pm *ProtocolManager) txsyncLoop() { + var ( + pending = make(map[enode.ID]*txsync) + sending = false // whether a send is active + pack = new(txsync) // the pack that is being sent + done = make(chan error, 1) // result of the send + ) + + // send starts a sending a pack of transactions from the sync. + send := func(s *txsync) { + // Fill pack with transactions up to the target size. + size := common.StorageSize(0) + pack.p = s.p + pack.txs = pack.txs[:0] + for i := 0; i < len(s.txs) && size < txsyncPackSize; i++ { + pack.txs = append(pack.txs, s.txs[i]) + size += s.txs[i].Size() + } + // Remove the transactions that will be sent. + s.txs = s.txs[:copy(s.txs, s.txs[len(pack.txs):])] + if len(s.txs) == 0 { + delete(pending, s.p.ID()) + } + // Send the pack in the background. + s.p.Log().Trace("Sending batch of transactions", "count", len(pack.txs), "bytes", size) + sending = true + go func() { done <- pack.p.SendTransactions(pack.txs) }() + } + + // pick chooses the next pending sync. + pick := func() *txsync { + if len(pending) == 0 { + return nil + } + n := rand.Intn(len(pending)) + 1 + for _, s := range pending { + if n--; n == 0 { + return s + } + } + return nil + } + + for { + select { + case s := <-pm.txsyncCh: + pending[s.p.ID()] = s + if !sending { + send(s) + } + case err := <-done: + sending = false + // Stop tracking peers that cause send failures. + if err != nil { + pack.p.Log().Debug("Transaction send failed", "err", err) + delete(pending, pack.p.ID()) + } + // Schedule the next send. + if s := pick(); s != nil { + send(s) + } + case <-pm.quitSync: + return + } + } +} + +// syncer is responsible for periodically synchronising with the network, both +// downloading hashes and blocks as well as handling the announcement handler. +func (pm *ProtocolManager) syncer() { + // Start and ensure cleanup of sync mechanisms + pm.fetcher.Start() + defer pm.fetcher.Stop() + defer pm.downloader.Terminate() + + // Wait for different events to fire synchronisation operations + forceSync := time.NewTicker(forceSyncCycle) + defer forceSync.Stop() + + for { + select { + case <-pm.newPeerCh: + // Make sure we have peers to select from, then sync + if pm.peers.Len() < minDesiredPeerCount { + break + } + go pm.synchronise(pm.peers.BestPeer()) + + case <-forceSync.C: + // Force a sync even if not enough peers are present + go pm.synchronise(pm.peers.BestPeer()) + + case <-pm.noMorePeers: + return + } + } +} + +// synchronise tries to sync up our local block chain with a remote peer. +func (pm *ProtocolManager) synchronise(peer *peer) { + // Short circuit if no peers are available + if peer == nil { + return + } + // Make sure the peer's TD is higher than our own + currentBlock := pm.blockchain.CurrentBlock() + td := pm.blockchain.GetTd(currentBlock.Hash(), currentBlock.NumberU64()) + + pHead, pTd := peer.Head() + if pTd.Cmp(td) <= 0 { + return + } + // Otherwise try to sync with the downloader + mode := downloader.FullSync + if atomic.LoadUint32(&pm.fastSync) == 1 { + // Fast sync was explicitly requested, and explicitly granted + mode = downloader.FastSync + } + if mode == downloader.FastSync { + // Make sure the peer's total difficulty we are synchronizing is higher. + if pm.blockchain.GetTdByHash(pm.blockchain.CurrentFastBlock().Hash()).Cmp(pTd) >= 0 { + return + } + } + // Run the sync cycle, and disable fast sync if we've went past the pivot block + if err := pm.downloader.Synchronise(peer.id, pHead, pTd, mode); err != nil { + return + } + if atomic.LoadUint32(&pm.fastSync) == 1 { + log.Info("Fast sync complete, auto disabling") + atomic.StoreUint32(&pm.fastSync, 0) + } + // If we've successfully finished a sync cycle and passed any required checkpoint, + // enable accepting transactions from the network. + head := pm.blockchain.CurrentBlock() + if head.NumberU64() >= pm.checkpointNumber { + // Checkpoint passed, sanity check the timestamp to have a fallback mechanism + // for non-checkpointed (number = 0) private networks. + if head.Time() >= uint64(time.Now().AddDate(0, -1, 0).Unix()) { + atomic.StoreUint32(&pm.acceptTxs, 1) + } + } + if head.NumberU64() > 0 { + // We've completed a sync cycle, notify all peers of new state. This path is + // essential in star-topology networks where a gateway node needs to notify + // all its out-of-date peers of the availability of a new block. This failure + // scenario will most often crop up in private and hackathon networks with + // degenerate connectivity, but it should be healthy for the mainnet too to + // more reliably update peers or the local TD state. + go pm.BroadcastBlock(head, false) + } +} -- cgit v1.2.3