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package core
import (
"context"
"errors"
"fmt"
"io"
"math/rand"
"sync"
"time"
math2 "github.com/ipfs/go-ipfs/thirdparty/math2"
lgbl "gx/ipfs/QmZ4zF1mBrt8C2mSCM4ZYE4aAnv78f7GvrzufJC4G5tecK/go-libp2p-loggables"
peer "gx/ipfs/QmQsErDt8Qgw1XrsXf2BpEzDgGWtB1YLsTAARBup5b6B9W/go-libp2p-peer"
goprocess "gx/ipfs/QmSF8fPo3jgVBAy8fpdjjYqgG87dkJgUprRBHRd2tmfgpP/goprocess"
procctx "gx/ipfs/QmSF8fPo3jgVBAy8fpdjjYqgG87dkJgUprRBHRd2tmfgpP/goprocess/context"
periodicproc "gx/ipfs/QmSF8fPo3jgVBAy8fpdjjYqgG87dkJgUprRBHRd2tmfgpP/goprocess/periodic"
config "gx/ipfs/QmYVqYJTVjetcf1guieEgWpK1PZtHPytP624vKzTF1P3r2/go-ipfs-config"
inet "gx/ipfs/QmZNJyx9GGCX4GeuHnLB8fxaxMLs4MjTjHokxfQcCd6Nve/go-libp2p-net"
pstore "gx/ipfs/Qmda4cPRvSRyox3SqgJN6DfSZGU5TtHufPTp9uXjFj71X6/go-libp2p-peerstore"
host "gx/ipfs/QmeMYW7Nj8jnnEfs9qhm7SxKkoDPUWXu3MsxX6BFwz34tf/go-libp2p-host"
)
// ErrNotEnoughBootstrapPeers signals that we do not have enough bootstrap
// peers to bootstrap correctly.
var ErrNotEnoughBootstrapPeers = errors.New("not enough bootstrap peers to bootstrap")
// BootstrapConfig specifies parameters used in an IpfsNode's network
// bootstrapping process.
type BootstrapConfig struct {
// MinPeerThreshold governs whether to bootstrap more connections. If the
// node has less open connections than this number, it will open connections
// to the bootstrap nodes. From there, the routing system should be able
// to use the connections to the bootstrap nodes to connect to even more
// peers. Routing systems like the IpfsDHT do so in their own Bootstrap
// process, which issues random queries to find more peers.
MinPeerThreshold int
// Period governs the periodic interval at which the node will
// attempt to bootstrap. The bootstrap process is not very expensive, so
// this threshold can afford to be small (<=30s).
Period time.Duration
// ConnectionTimeout determines how long to wait for a bootstrap
// connection attempt before cancelling it.
ConnectionTimeout time.Duration
// BootstrapPeers is a function that returns a set of bootstrap peers
// for the bootstrap process to use. This makes it possible for clients
// to control the peers the process uses at any moment.
BootstrapPeers func() []pstore.PeerInfo
}
// DefaultBootstrapConfig specifies default sane parameters for bootstrapping.
var DefaultBootstrapConfig = BootstrapConfig{
MinPeerThreshold: 4,
Period: 30 * time.Second,
ConnectionTimeout: (30 * time.Second) / 3, // Perod / 3
}
func BootstrapConfigWithPeers(pis []pstore.PeerInfo) BootstrapConfig {
cfg := DefaultBootstrapConfig
cfg.BootstrapPeers = func() []pstore.PeerInfo {
return pis
}
return cfg
}
// Bootstrap kicks off IpfsNode bootstrapping. This function will periodically
// check the number of open connections and -- if there are too few -- initiate
// connections to well-known bootstrap peers. It also kicks off subsystem
// bootstrapping (i.e. routing).
func Bootstrap(n *IpfsNode, cfg BootstrapConfig) (io.Closer, error) {
// make a signal to wait for one bootstrap round to complete.
doneWithRound := make(chan struct{})
// the periodic bootstrap function -- the connection supervisor
periodic := func(worker goprocess.Process) {
ctx := procctx.OnClosingContext(worker)
defer log.EventBegin(ctx, "periodicBootstrap", n.Identity).Done()
if err := bootstrapRound(ctx, n.PeerHost, cfg); err != nil {
log.Event(ctx, "bootstrapError", n.Identity, lgbl.Error(err))
log.Debugf("%s bootstrap error: %s", n.Identity, err)
}
<-doneWithRound
}
// kick off the node's periodic bootstrapping
proc := periodicproc.Tick(cfg.Period, periodic)
proc.Go(periodic) // run one right now.
// kick off Routing.Bootstrap
if n.Routing != nil {
ctx := procctx.OnClosingContext(proc)
if err := n.Routing.Bootstrap(ctx); err != nil {
proc.Close()
return nil, err
}
}
doneWithRound <- struct{}{}
close(doneWithRound) // it no longer blocks periodic
return proc, nil
}
func bootstrapRound(ctx context.Context, host host.Host, cfg BootstrapConfig) error {
ctx, cancel := context.WithTimeout(ctx, cfg.ConnectionTimeout)
defer cancel()
id := host.ID()
// get bootstrap peers from config. retrieving them here makes
// sure we remain observant of changes to client configuration.
peers := cfg.BootstrapPeers()
// determine how many bootstrap connections to open
connected := host.Network().Peers()
if len(connected) >= cfg.MinPeerThreshold {
log.Event(ctx, "bootstrapSkip", id)
log.Debugf("%s core bootstrap skipped -- connected to %d (> %d) nodes",
id, len(connected), cfg.MinPeerThreshold)
return nil
}
numToDial := cfg.MinPeerThreshold - len(connected)
// filter out bootstrap nodes we are already connected to
var notConnected []pstore.PeerInfo
for _, p := range peers {
if host.Network().Connectedness(p.ID) != inet.Connected {
notConnected = append(notConnected, p)
}
}
// if connected to all bootstrap peer candidates, exit
if len(notConnected) < 1 {
log.Debugf("%s no more bootstrap peers to create %d connections", id, numToDial)
if len(peers) == 0 {
// We *need* to bootstrap but we have no bootstrap peers
// configured *at all*, inform the user.
log.Error("no bootstrap nodes configured: go-ipfs may have difficulty connecting to the network")
}
return ErrNotEnoughBootstrapPeers
}
// connect to a random susbset of bootstrap candidates
randSubset := randomSubsetOfPeers(notConnected, numToDial)
defer log.EventBegin(ctx, "bootstrapStart", id).Done()
log.Debugf("%s bootstrapping to %d nodes: %s", id, numToDial, randSubset)
return bootstrapConnect(ctx, host, randSubset)
}
func bootstrapConnect(ctx context.Context, ph host.Host, peers []pstore.PeerInfo) error {
if len(peers) < 1 {
return ErrNotEnoughBootstrapPeers
}
errs := make(chan error, len(peers))
var wg sync.WaitGroup
for _, p := range peers {
// performed asynchronously because when performed synchronously, if
// one `Connect` call hangs, subsequent calls are more likely to
// fail/abort due to an expiring context.
// Also, performed asynchronously for dial speed.
wg.Add(1)
go func(p pstore.PeerInfo) {
defer wg.Done()
defer log.EventBegin(ctx, "bootstrapDial", ph.ID(), p.ID).Done()
log.Debugf("%s bootstrapping to %s", ph.ID(), p.ID)
ph.Peerstore().AddAddrs(p.ID, p.Addrs, pstore.PermanentAddrTTL)
if err := ph.Connect(ctx, p); err != nil {
log.Event(ctx, "bootstrapDialFailed", p.ID)
log.Debugf("failed to bootstrap with %v: %s", p.ID, err)
errs <- err
return
}
log.Event(ctx, "bootstrapDialSuccess", p.ID)
log.Infof("bootstrapped with %v", p.ID)
}(p)
}
wg.Wait()
// our failure condition is when no connection attempt succeeded.
// So drain the errs channel, counting the results.
close(errs)
count := 0
var err error
for err = range errs {
if err != nil {
count++
}
}
if count == len(peers) {
return fmt.Errorf("failed to bootstrap. %s", err)
}
return nil
}
func toPeerInfos(bpeers []config.BootstrapPeer) []pstore.PeerInfo {
pinfos := make(map[peer.ID]*pstore.PeerInfo)
for _, bootstrap := range bpeers {
pinfo, ok := pinfos[bootstrap.ID()]
if !ok {
pinfo = new(pstore.PeerInfo)
pinfos[bootstrap.ID()] = pinfo
pinfo.ID = bootstrap.ID()
}
pinfo.Addrs = append(pinfo.Addrs, bootstrap.Transport())
}
var peers []pstore.PeerInfo
for _, pinfo := range pinfos {
peers = append(peers, *pinfo)
}
return peers
}
func randomSubsetOfPeers(in []pstore.PeerInfo, max int) []pstore.PeerInfo {
n := math2.IntMin(max, len(in))
var out []pstore.PeerInfo
for _, val := range rand.Perm(len(in)) {
out = append(out, in[val])
if len(out) >= n {
break
}
}
return out
}