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discover.go
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discover.go
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package discv5
import (
"context"
"crypto/ecdsa"
"math/rand"
"net"
"sync"
"time"
"github.com/ethereum/go-ethereum/p2p/enode"
"github.com/ethereum/go-ethereum/p2p/enr"
"github.com/ethereum/go-ethereum/p2p/nat"
"github.com/libp2p/go-libp2p-core/discovery"
"github.com/libp2p/go-libp2p-core/host"
"github.com/libp2p/go-libp2p-core/peer"
"github.com/status-im/go-discover/discover"
"github.com/status-im/go-waku/logging"
"github.com/status-im/go-waku/waku/v2/utils"
"go.uber.org/zap"
)
type DiscoveryV5 struct {
sync.Mutex
discovery.Discovery
params *discV5Parameters
host host.Host
config discover.Config
udpAddr *net.UDPAddr
listener *discover.UDPv5
localnode *enode.LocalNode
NAT nat.Interface
quit chan struct{}
log *zap.Logger
wg *sync.WaitGroup
peerCache peerCache
}
type peerCache struct {
sync.RWMutex
recs map[peer.ID]peerRecord
rng *rand.Rand
}
type peerRecord struct {
expire int64
peer peer.AddrInfo
}
type discV5Parameters struct {
autoUpdate bool
bootnodes []*enode.Node
udpPort int
advertiseAddr *net.IP
}
type DiscoveryV5Option func(*discV5Parameters)
func WithAutoUpdate(autoUpdate bool) DiscoveryV5Option {
return func(params *discV5Parameters) {
params.autoUpdate = autoUpdate
}
}
func WithBootnodes(bootnodes []*enode.Node) DiscoveryV5Option {
return func(params *discV5Parameters) {
params.bootnodes = bootnodes
}
}
func WithAdvertiseAddr(addr net.IP) DiscoveryV5Option {
return func(params *discV5Parameters) {
params.advertiseAddr = &addr
}
}
func WithUDPPort(port int) DiscoveryV5Option {
return func(params *discV5Parameters) {
params.udpPort = port
}
}
func DefaultOptions() []DiscoveryV5Option {
return []DiscoveryV5Option{
WithUDPPort(9000),
}
}
func NewDiscoveryV5(host host.Host, priv *ecdsa.PrivateKey, localnode *enode.LocalNode, log *zap.Logger, opts ...DiscoveryV5Option) (*DiscoveryV5, error) {
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()
}
return &DiscoveryV5{
host: host,
params: params,
NAT: NAT,
wg: &sync.WaitGroup{},
peerCache: peerCache{
rng: rand.New(rand.NewSource(rand.Int63())),
recs: make(map[peer.ID]peerRecord),
},
localnode: localnode,
config: discover.Config{
PrivateKey: priv,
Bootnodes: params.bootnodes,
ValidNodeFn: func(n enode.Node) bool {
// TODO: track https://github.com/status-im/nim-waku/issues/770 for improvements over validation func
return evaluateNode(&n)
},
V5Config: discover.V5Config{
ProtocolID: [6]byte{'d', '5', 'w', 'a', 'k', 'u'},
},
},
udpAddr: &net.UDPAddr{
IP: net.IPv4zero,
Port: params.udpPort,
},
log: logger,
}, nil
}
func (d *DiscoveryV5) listen() error {
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, d.quit, "udp", d.udpAddr.Port, d.udpAddr.Port, "go-waku discv5 discovery")
}()
}
d.localnode.SetFallbackUDP(d.udpAddr.Port)
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()))
return nil
}
func (d *DiscoveryV5) Start() error {
d.Lock()
defer d.Unlock()
d.wg.Wait() // Waiting for other go routines to stop
d.quit = make(chan struct{}, 1)
err := d.listen()
if err != nil {
return err
}
return nil
}
func (d *DiscoveryV5) Stop() {
d.Lock()
defer d.Unlock()
close(d.quit)
d.listener.Close()
d.listener = nil
d.log.Info("stopped Discovery V5")
d.wg.Wait()
}
/*
func isWakuNode(node *enode.Node) bool {
enrField := new(utils.WakuEnrBitfield)
if err := node.Record().Load(enr.WithEntry(utils.WakuENRField, &enrField)); err != nil {
if !enr.IsNotFound(err) {
utils.Logger().Named("discv5").Error("could not retrieve port for enr ", zap.Any("node", node))
}
return false
}
if enrField != nil {
return *enrField != uint8(0)
}
return false
}
*/
func hasTCPPort(node *enode.Node) bool {
enrTCP := new(enr.TCP)
if err := node.Record().Load(enr.WithEntry(enrTCP.ENRKey(), enrTCP)); err != nil {
if !enr.IsNotFound(err) {
utils.Logger().Named("discv5").Error("retrieving port for enr", logging.ENode("enr", node))
}
return false
}
return true
}
func evaluateNode(node *enode.Node) bool {
if node == nil || node.IP() == nil {
return false
}
// TODO: consider node filtering based on ENR; we do not filter based on ENR in the first waku discv5 beta stage
if /*!isWakuNode(node) ||*/ !hasTCPPort(node) {
return false
}
_, err := utils.EnodeToPeerInfo(node)
if err != nil {
utils.Logger().Named("discv5").Error("obtaining peer info from enode", logging.ENode("enr", node), zap.Error(err))
return false
}
return true
}
func (d *DiscoveryV5) Advertise(ctx context.Context, ns string, opts ...discovery.Option) (time.Duration, error) {
// Get options
var options discovery.Options
err := options.Apply(opts...)
if err != nil {
return 0, err
}
// TODO: once discv5 spec introduces capability and topic discovery, implement this function
return 20 * time.Minute, nil
}
func (d *DiscoveryV5) iterate(ctx context.Context, iterator enode.Iterator, limit int, doneCh chan struct{}) {
defer d.wg.Done()
for {
if len(d.peerCache.recs) >= limit {
break
}
if ctx.Err() != nil {
break
}
exists := iterator.Next()
if !exists {
break
}
addresses, err := utils.Multiaddress(iterator.Node())
if err != nil {
d.log.Error("extracting multiaddrs from enr", zap.Error(err))
continue
}
peerAddrs, err := peer.AddrInfosFromP2pAddrs(addresses...)
if err != nil {
d.log.Error("converting multiaddrs to addrinfos", zap.Error(err))
continue
}
for _, p := range peerAddrs {
d.peerCache.recs[p.ID] = peerRecord{
expire: time.Now().Unix() + 3600, // Expires in 1hr
peer: p,
}
}
}
close(doneCh)
}
func (d *DiscoveryV5) removeExpiredPeers() int {
// Remove all expired entries from cache
currentTime := time.Now().Unix()
newCacheSize := len(d.peerCache.recs)
for p := range d.peerCache.recs {
rec := d.peerCache.recs[p]
if rec.expire < currentTime {
newCacheSize--
delete(d.peerCache.recs, p)
}
}
return newCacheSize
}
func (d *DiscoveryV5) FindPeers(ctx context.Context, topic string, opts ...discovery.Option) (<-chan peer.AddrInfo, error) {
// Get options
var options discovery.Options
err := options.Apply(opts...)
if err != nil {
return nil, err
}
const maxLimit = 100
limit := options.Limit
if limit == 0 || limit > maxLimit {
limit = maxLimit
}
// We are ignoring the topic. Future versions might use a map[string]*peerCache instead where the string represents the pubsub topic
d.peerCache.Lock()
defer d.peerCache.Unlock()
cacheSize := d.removeExpiredPeers()
// Discover new records if we don't have enough
if cacheSize < limit && d.listener != nil {
d.Lock()
iterator := d.listener.RandomNodes()
iterator = enode.Filter(iterator, evaluateNode)
defer iterator.Close()
doneCh := make(chan struct{})
d.wg.Add(1)
go d.iterate(ctx, iterator, limit, doneCh)
select {
case <-ctx.Done():
case <-doneCh:
}
d.Unlock()
}
// Randomize and fill channel with available records
count := len(d.peerCache.recs)
if limit < count {
count = limit
}
chPeer := make(chan peer.AddrInfo, count)
perm := d.peerCache.rng.Perm(len(d.peerCache.recs))[0:count]
permSet := make(map[int]int)
for i, v := range perm {
permSet[v] = i
}
sendLst := make([]*peer.AddrInfo, count)
iter := 0
for k := range d.peerCache.recs {
if sendIndex, ok := permSet[iter]; ok {
peerInfo := d.peerCache.recs[k].peer
sendLst[sendIndex] = &peerInfo
}
iter++
}
for _, send := range sendLst {
chPeer <- *send
}
close(chPeer)
return chPeer, err
}