go-waku/waku/v2/discovery/enr.go

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package discovery
import (
"context"
"fmt"
"github.com/ethereum/go-ethereum/p2p/dnsdisc"
"github.com/ethereum/go-ethereum/p2p/enode"
"github.com/libp2p/go-libp2p-core/peer"
ma "github.com/multiformats/go-multiaddr"
)
type DnsDiscoveryParameters struct {
nameserver string
}
type DnsDiscoveryOption func(*DnsDiscoveryParameters)
// WithMultiaddress is a WakuNodeOption that configures libp2p to listen on a list of multiaddresses
func WithNameserver(nameserver string) DnsDiscoveryOption {
return func(params *DnsDiscoveryParameters) {
params.nameserver = nameserver
}
}
// RetrieveNodes returns a list of multiaddress given a url to a DNS discoverable
// ENR tree
func RetrieveNodes(ctx context.Context, url string, opts ...DnsDiscoveryOption) ([]ma.Multiaddr, error) {
var multiAddrs []ma.Multiaddr
params := new(DnsDiscoveryParameters)
for _, opt := range opts {
opt(params)
}
client := dnsdisc.NewClient(dnsdisc.Config{
Resolver: GetResolver(ctx, params.nameserver),
})
tree, err := client.SyncTree(url)
if err != nil {
return nil, err
}
for _, node := range tree.Nodes() {
m, err := EnodeToMultiAddr(node)
if err != nil {
return nil, err
}
multiAddrs = append(multiAddrs, m)
}
return multiAddrs, nil
}
func EnodeToMultiAddr(node *enode.Node) (ma.Multiaddr, error) {
peerID, err := peer.IDFromPublicKey(&ECDSAPublicKey{node.Pubkey()})
if err != nil {
return nil, err
}
return ma.NewMultiaddr(fmt.Sprintf("/ip4/%s/tcp/%d/p2p/%s", node.IP(), node.TCP(), peerID))
}