Official Go implementation of the Ethereum protocol
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go-ethereum/cmd/devp2p/crawl.go

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4.9 KiB

// Copyright 2019 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// go-ethereum 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
package main
import (
"sync"
"sync/atomic"
"time"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/p2p/enode"
)
type crawler struct {
input nodeSet
output nodeSet
disc resolver
iters []enode.Iterator
inputIter enode.Iterator
ch chan *enode.Node
closed chan struct{}
// settings
revalidateInterval time.Duration
mu sync.RWMutex
}
const (
nodeRemoved = iota
nodeSkipRecent
nodeSkipIncompat
nodeAdded
nodeUpdated
)
type resolver interface {
RequestENR(*enode.Node) (*enode.Node, error)
}
func newCrawler(input nodeSet, disc resolver, iters ...enode.Iterator) *crawler {
c := &crawler{
input: input,
output: make(nodeSet, len(input)),
disc: disc,
iters: iters,
inputIter: enode.IterNodes(input.nodes()),
ch: make(chan *enode.Node),
closed: make(chan struct{}),
}
c.iters = append(c.iters, c.inputIter)
// Copy input to output initially. Any nodes that fail validation
// will be dropped from output during the run.
for id, n := range input {
c.output[id] = n
}
return c
}
func (c *crawler) run(timeout time.Duration, nthreads int) nodeSet {
var (
timeoutTimer = time.NewTimer(timeout)
timeoutCh <-chan time.Time
statusTicker = time.NewTicker(time.Second * 8)
doneCh = make(chan enode.Iterator, len(c.iters))
liveIters = len(c.iters)
)
if nthreads < 1 {
nthreads = 1
}
defer timeoutTimer.Stop()
defer statusTicker.Stop()
for _, it := range c.iters {
go c.runIterator(doneCh, it)
}
var (
added atomic.Uint64
updated atomic.Uint64
skipped atomic.Uint64
recent atomic.Uint64
removed atomic.Uint64
wg sync.WaitGroup
)
wg.Add(nthreads)
for i := 0; i < nthreads; i++ {
go func() {
defer wg.Done()
for {
select {
case n := <-c.ch:
switch c.updateNode(n) {
case nodeSkipIncompat:
skipped.Add(1)
case nodeSkipRecent:
recent.Add(1)
case nodeRemoved:
removed.Add(1)
case nodeAdded:
added.Add(1)
default:
updated.Add(1)
}
case <-c.closed:
return
}
}
}()
}
loop:
for {
select {
case it := <-doneCh:
if it == c.inputIter {
// Enable timeout when we're done revalidating the input nodes.
log.Info("Revalidation of input set is done", "len", len(c.input))
if timeout > 0 {
timeoutCh = timeoutTimer.C
}
}
if liveIters--; liveIters == 0 {
break loop
}
case <-timeoutCh:
break loop
case <-statusTicker.C:
log.Info("Crawling in progress",
"added", added.Load(),
"updated", updated.Load(),
"removed", removed.Load(),
"ignored(recent)", recent.Load(),
"ignored(incompatible)", skipped.Load())
}
}
close(c.closed)
for _, it := range c.iters {
it.Close()
}
for ; liveIters > 0; liveIters-- {
<-doneCh
}
wg.Wait()
return c.output
}
func (c *crawler) runIterator(done chan<- enode.Iterator, it enode.Iterator) {
defer func() { done <- it }()
for it.Next() {
select {
case c.ch <- it.Node():
case <-c.closed:
return
}
}
}
// updateNode updates the info about the given node, and returns a status
// about what changed
func (c *crawler) updateNode(n *enode.Node) int {
c.mu.RLock()
node, ok := c.output[n.ID()]
c.mu.RUnlock()
// Skip validation of recently-seen nodes.
if ok && time.Since(node.LastCheck) < c.revalidateInterval {
return nodeSkipRecent
}
// Request the node record.
status := nodeUpdated
node.LastCheck = truncNow()
if nn, err := c.disc.RequestENR(n); err != nil {
if node.Score == 0 {
// Node doesn't implement EIP-868.
log.Debug("Skipping node", "id", n.ID())
return nodeSkipIncompat
}
node.Score /= 2
} else {
node.N = nn
node.Seq = nn.Seq()
node.Score++
if node.FirstResponse.IsZero() {
node.FirstResponse = node.LastCheck
status = nodeAdded
}
node.LastResponse = node.LastCheck
}
// Store/update node in output set.
c.mu.Lock()
defer c.mu.Unlock()
if node.Score <= 0 {
log.Debug("Removing node", "id", n.ID())
delete(c.output, n.ID())
return nodeRemoved
}
log.Debug("Updating node", "id", n.ID(), "seq", n.Seq(), "score", node.Score)
c.output[n.ID()] = node
return status
}
func truncNow() time.Time {
return time.Now().UTC().Truncate(1 * time.Second)
}