go-waku/waku/v2/discv5/discover.go

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package discv5
import (
"context"
"crypto/ecdsa"
"errors"
"fmt"
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"net"
"sync"
"sync/atomic"
"time"
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"github.com/libp2p/go-libp2p/core/host"
"github.com/libp2p/go-libp2p/core/peer"
"github.com/multiformats/go-multiaddr"
"github.com/waku-org/go-discover/discover"
"github.com/waku-org/go-waku/logging"
v2 "github.com/waku-org/go-waku/waku/v2"
"github.com/waku-org/go-waku/waku/v2/metrics"
"github.com/waku-org/go-waku/waku/v2/peers"
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wenr "github.com/waku-org/go-waku/waku/v2/protocol/enr"
"github.com/waku-org/go-waku/waku/v2/utils"
"go.uber.org/zap"
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"github.com/ethereum/go-ethereum/p2p/enode"
"github.com/ethereum/go-ethereum/p2p/nat"
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)
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var ErrNoDiscV5Listener = errors.New("no discv5 listener")
type PeerConnector interface {
Subscribe(context.Context, <-chan v2.PeerData)
}
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type DiscoveryV5 struct {
params *discV5Parameters
host host.Host
config discover.Config
udpAddr *net.UDPAddr
listener *discover.UDPv5
localnode *enode.LocalNode
peerConnector PeerConnector
peerCh chan v2.PeerData
NAT nat.Interface
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log *zap.Logger
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started atomic.Bool
cancel context.CancelFunc
wg *sync.WaitGroup
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}
type discV5Parameters struct {
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autoUpdate bool
autoFindPeers bool
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bootnodes []*enode.Node
udpPort uint
advertiseAddr []multiaddr.Multiaddr
loopPredicate func(*enode.Node) bool
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}
type DiscoveryV5Option func(*discV5Parameters)
var protocolID = [6]byte{'d', '5', 'w', 'a', 'k', 'u'}
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const peerDelay = 100 * time.Millisecond
const bucketSize = 16
const delayBetweenDiscoveredPeerCnt = 5 * time.Second
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func WithAutoUpdate(autoUpdate bool) DiscoveryV5Option {
return func(params *discV5Parameters) {
params.autoUpdate = autoUpdate
}
}
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func WithBootnodes(bootnodes []*enode.Node) DiscoveryV5Option {
return func(params *discV5Parameters) {
params.bootnodes = bootnodes
}
}
func WithAdvertiseAddr(addr []multiaddr.Multiaddr) DiscoveryV5Option {
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return func(params *discV5Parameters) {
params.advertiseAddr = addr
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}
}
func WithUDPPort(port uint) DiscoveryV5Option {
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return func(params *discV5Parameters) {
params.udpPort = port
}
}
func WithPredicate(predicate func(*enode.Node) bool) DiscoveryV5Option {
return func(params *discV5Parameters) {
params.loopPredicate = predicate
}
}
func WithAutoFindPeers(find bool) DiscoveryV5Option {
return func(params *discV5Parameters) {
params.autoFindPeers = find
}
}
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func DefaultOptions() []DiscoveryV5Option {
return []DiscoveryV5Option{
WithUDPPort(9000),
WithAutoFindPeers(true),
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}
}
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func NewDiscoveryV5(priv *ecdsa.PrivateKey, localnode *enode.LocalNode, peerConnector PeerConnector, log *zap.Logger, opts ...DiscoveryV5Option) (*DiscoveryV5, error) {
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params := new(discV5Parameters)
optList := DefaultOptions()
optList = append(optList, opts...)
for _, opt := range optList {
opt(params)
}
logger := log.Named("discv5")
var NAT nat.Interface = nil
if params.advertiseAddr == nil {
NAT = nat.Any()
}
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return &DiscoveryV5{
params: params,
peerConnector: peerConnector,
NAT: NAT,
wg: &sync.WaitGroup{},
localnode: localnode,
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config: discover.Config{
PrivateKey: priv,
Bootnodes: params.bootnodes,
V5Config: discover.V5Config{
ProtocolID: &protocolID,
},
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},
udpAddr: &net.UDPAddr{
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IP: net.IPv4zero,
Port: int(params.udpPort),
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},
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log: logger,
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}, nil
}
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func (d *DiscoveryV5) Node() *enode.Node {
return d.localnode.Node()
}
func (d *DiscoveryV5) listen(ctx context.Context) error {
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conn, err := net.ListenUDP("udp", d.udpAddr)
if err != nil {
return err
}
d.udpAddr = conn.LocalAddr().(*net.UDPAddr)
if d.NAT != nil && !d.udpAddr.IP.IsLoopback() {
d.wg.Add(1)
go func() {
defer d.wg.Done()
nat.Map(d.NAT, ctx.Done(), "udp", d.udpAddr.Port, d.udpAddr.Port, "go-waku discv5 discovery")
}()
}
d.localnode.SetFallbackUDP(d.udpAddr.Port)
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listener, err := discover.ListenV5(conn, d.localnode, d.config)
if err != nil {
return err
}
d.listener = listener
d.log.Info("started Discovery V5",
zap.Stringer("listening", d.udpAddr),
logging.TCPAddr("advertising", d.localnode.Node().IP(), d.localnode.Node().TCP()))
d.log.Info("Discovery V5: discoverable ENR ", logging.ENode("enr", d.localnode.Node()))
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return nil
}
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// Sets the host to be able to mount or consume a protocol
func (d *DiscoveryV5) SetHost(h host.Host) {
d.host = h
}
// only works if the discovery v5 hasn't been started yet.
func (d *DiscoveryV5) Start(ctx context.Context) error {
// compare and swap sets the discovery v5 to `started` state
// and prevents multiple calls to the start method by being atomic.
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if !d.started.CompareAndSwap(false, true) {
return nil
}
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ctx, cancel := context.WithCancel(ctx)
d.cancel = cancel
d.peerCh = make(chan v2.PeerData)
d.peerConnector.Subscribe(ctx, d.peerCh)
err := d.listen(ctx)
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if err != nil {
return err
}
if d.params.autoFindPeers {
d.wg.Add(1)
go func() {
defer d.wg.Done()
d.runDiscoveryV5Loop(ctx)
}()
}
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return nil
}
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func (d *DiscoveryV5) SetBootnodes(nodes []*enode.Node) error {
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if d.listener == nil {
return ErrNoDiscV5Listener
}
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return d.listener.SetFallbackNodes(nodes)
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}
// only works if the discovery v5 is in running state
// so we can assume that cancel method is set
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func (d *DiscoveryV5) Stop() {
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if !d.started.CompareAndSwap(true, false) { // if Discoveryv5 is running, set started to false
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return
}
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d.cancel()
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if d.listener != nil {
d.listener.Close()
d.listener = nil
d.log.Info("stopped Discovery V5")
}
d.wg.Wait()
close(d.peerCh)
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}
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/*
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func isWakuNode(node *enode.Node) bool {
enrField := new(utils.WakuEnrBitfield)
if err := node.Record().Load(enr.WithEntry(utils.WakuENRField, &enrField)); err != nil {
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if !enr.IsNotFound(err) {
utils.Logger().Named("discv5").Error("could not retrieve port for enr ", zap.Any("node", node))
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}
return false
}
if enrField != nil {
return *enrField != uint8(0)
}
return false
}
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*/
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func evaluateNode(node *enode.Node) bool {
if node == nil {
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return false
}
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// TODO: consider node filtering based on ENR; we do not filter based on ENR in the first waku discv5 beta stage
/*if !isWakuNode(node) {
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return false
}*/
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_, err := wenr.EnodeToPeerInfo(node)
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if err != nil {
metrics.RecordDiscV5Error(context.Background(), "peer_info_failure")
utils.Logger().Named("discv5").Error("obtaining peer info from enode", logging.ENode("enr", node), zap.Error(err))
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return false
}
return true
}
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// Predicate is a function that is applied to an iterator to filter the nodes to be retrieved according to some logic
type Predicate func(enode.Iterator) enode.Iterator
// PeerIterator gets random nodes from DHT via discv5 listener.
// Used for caching enr address in peerExchange
// Used for connecting to peers in discovery_connector
func (d *DiscoveryV5) PeerIterator(predicate ...Predicate) (enode.Iterator, error) {
if d.listener == nil {
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return nil, ErrNoDiscV5Listener
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}
iterator := enode.Filter(d.listener.RandomNodes(), evaluateNode)
if d.params.loopPredicate != nil {
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iterator = enode.Filter(iterator, d.params.loopPredicate)
}
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for _, p := range predicate {
iterator = p(iterator)
}
return iterator, nil
}
func (d *DiscoveryV5) Iterate(ctx context.Context, iterator enode.Iterator, onNode func(*enode.Node, peer.AddrInfo) error) {
defer iterator.Close()
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peerCnt := 0
for {
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if !delayedHasNext(ctx, iterator) {
return
}
peerCnt++
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if peerCnt == bucketSize { // Delay every bucketSize peers discovered
peerCnt = 0
t := time.NewTimer(delayBetweenDiscoveredPeerCnt)
select {
case <-ctx.Done():
return
case <-t.C:
t.Stop()
}
}
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_, addresses, err := wenr.Multiaddress(iterator.Node())
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if err != nil {
metrics.RecordDiscV5Error(context.Background(), "peer_info_failure")
d.log.Error("extracting multiaddrs from enr", zap.Error(err))
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continue
}
peerAddrs, err := peer.AddrInfosFromP2pAddrs(addresses...)
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if err != nil {
metrics.RecordDiscV5Error(context.Background(), "peer_info_failure")
d.log.Error("converting multiaddrs to addrinfos", zap.Error(err))
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continue
}
if len(peerAddrs) != 0 {
err := onNode(iterator.Node(), peerAddrs[0])
if err != nil {
d.log.Error("processing node", zap.Error(err))
}
}
select {
case <-ctx.Done():
return
default:
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}
}
}
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func delayedHasNext(ctx context.Context, iterator enode.Iterator) bool {
// Delay if .Next() is too fast
start := time.Now()
hasNext := iterator.Next()
if !hasNext {
return false
}
elapsed := time.Since(start)
if elapsed < peerDelay {
t := time.NewTimer(peerDelay - elapsed)
select {
case <-ctx.Done():
return false
case <-t.C:
t.Stop()
}
}
return true
}
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// Iterates over the nodes found via discv5 belonging to the node's current shard, and sends them to peerConnector
func (d *DiscoveryV5) peerLoop(ctx context.Context) error {
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iterator, err := d.PeerIterator(FilterPredicate(func(n *enode.Node) bool {
localRS, err := wenr.RelaySharding(d.localnode.Node().Record())
if err != nil {
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return false
}
if localRS == nil { // No shard registered, so no need to check for shards
return true
}
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nodeRS, err := wenr.RelaySharding(n.Record())
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if err != nil || nodeRS == nil {
return false
}
if nodeRS.Cluster != localRS.Cluster {
return false
}
// Contains any
for _, idx := range localRS.Indices {
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if nodeRS.Contains(localRS.Cluster, idx) {
return true
}
}
return false
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}))
if err != nil {
metrics.RecordDiscV5Error(context.Background(), "iterator_failure")
return fmt.Errorf("obtaining iterator: %w", err)
}
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defer iterator.Close()
d.Iterate(ctx, iterator, func(n *enode.Node, p peer.AddrInfo) error {
peer := v2.PeerData{
Origin: peers.Discv5,
AddrInfo: p,
ENR: n,
}
select {
case d.peerCh <- peer:
case <-ctx.Done():
return nil
}
return nil
})
return nil
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}
func (d *DiscoveryV5) runDiscoveryV5Loop(ctx context.Context) {
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restartLoop:
for {
err := d.peerLoop(ctx)
if err != nil {
d.log.Debug("iterating discv5", zap.Error(err))
}
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t := time.NewTimer(5 * time.Second)
select {
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case <-t.C:
t.Stop()
case <-ctx.Done():
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t.Stop()
break restartLoop
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}
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}
d.log.Warn("Discv5 loop stopped")
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}
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func (d *DiscoveryV5) IsStarted() bool {
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return d.started.Load()
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}