plugeth/cmd/devp2p/discv4cmd.go
Felix Lange 0568e81701
p2p/dnsdisc: add implementation of EIP-1459 (#20094)
This adds an implementation of node discovery via DNS TXT records to the
go-ethereum library. The implementation doesn't match EIP-1459 exactly,
the main difference being that this implementation uses separate merkle
trees for tree links and ENRs. The EIP will be updated to match p2p/dnsdisc.

To maintain DNS trees, cmd/devp2p provides a frontend for the p2p/dnsdisc
library. The new 'dns' subcommands can be used to create, sign and deploy DNS
discovery trees.
2019-09-25 11:38:13 +02:00

195 lines
4.8 KiB
Go

// 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 (
"fmt"
"net"
"strings"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/p2p/discover"
"github.com/ethereum/go-ethereum/p2p/enode"
"github.com/ethereum/go-ethereum/params"
"gopkg.in/urfave/cli.v1"
)
var (
discv4Command = cli.Command{
Name: "discv4",
Usage: "Node Discovery v4 tools",
Subcommands: []cli.Command{
discv4PingCommand,
discv4RequestRecordCommand,
discv4ResolveCommand,
discv4ResolveJSONCommand,
},
}
discv4PingCommand = cli.Command{
Name: "ping",
Usage: "Sends ping to a node",
Action: discv4Ping,
ArgsUsage: "<node>",
}
discv4RequestRecordCommand = cli.Command{
Name: "requestenr",
Usage: "Requests a node record using EIP-868 enrRequest",
Action: discv4RequestRecord,
ArgsUsage: "<node>",
}
discv4ResolveCommand = cli.Command{
Name: "resolve",
Usage: "Finds a node in the DHT",
Action: discv4Resolve,
ArgsUsage: "<node>",
Flags: []cli.Flag{bootnodesFlag},
}
discv4ResolveJSONCommand = cli.Command{
Name: "resolve-json",
Usage: "Re-resolves nodes in a nodes.json file",
Action: discv4ResolveJSON,
Flags: []cli.Flag{bootnodesFlag},
ArgsUsage: "<nodes.json file>",
}
)
var bootnodesFlag = cli.StringFlag{
Name: "bootnodes",
Usage: "Comma separated nodes used for bootstrapping",
}
func discv4Ping(ctx *cli.Context) error {
n := getNodeArg(ctx)
disc := startV4(ctx)
defer disc.Close()
start := time.Now()
if err := disc.Ping(n); err != nil {
return fmt.Errorf("node didn't respond: %v", err)
}
fmt.Printf("node responded to ping (RTT %v).\n", time.Since(start))
return nil
}
func discv4RequestRecord(ctx *cli.Context) error {
n := getNodeArg(ctx)
disc := startV4(ctx)
defer disc.Close()
respN, err := disc.RequestENR(n)
if err != nil {
return fmt.Errorf("can't retrieve record: %v", err)
}
fmt.Println(respN.String())
return nil
}
func discv4Resolve(ctx *cli.Context) error {
n := getNodeArg(ctx)
disc := startV4(ctx)
defer disc.Close()
fmt.Println(disc.Resolve(n).String())
return nil
}
func discv4ResolveJSON(ctx *cli.Context) error {
if ctx.NArg() < 1 {
return fmt.Errorf("need nodes file as argument")
}
disc := startV4(ctx)
defer disc.Close()
file := ctx.Args().Get(0)
// Load existing nodes in file.
var nodes []*enode.Node
if common.FileExist(file) {
nodes = loadNodesJSON(file).nodes()
}
// Add nodes from command line arguments.
for i := 1; i < ctx.NArg(); i++ {
n, err := parseNode(ctx.Args().Get(i))
if err != nil {
exit(err)
}
nodes = append(nodes, n)
}
result := make(nodeSet, len(nodes))
for _, n := range nodes {
n = disc.Resolve(n)
result[n.ID()] = nodeJSON{Seq: n.Seq(), N: n}
}
writeNodesJSON(file, result)
return nil
}
func parseBootnodes(ctx *cli.Context) ([]*enode.Node, error) {
s := params.RinkebyBootnodes
if ctx.IsSet(bootnodesFlag.Name) {
s = strings.Split(ctx.String(bootnodesFlag.Name), ",")
}
nodes := make([]*enode.Node, len(s))
var err error
for i, record := range s {
nodes[i], err = parseNode(record)
if err != nil {
return nil, fmt.Errorf("invalid bootstrap node: %v", err)
}
}
return nodes, nil
}
// startV4 starts an ephemeral discovery V4 node.
func startV4(ctx *cli.Context) *discover.UDPv4 {
socket, ln, cfg, err := listen()
if err != nil {
exit(err)
}
if commandHasFlag(ctx, bootnodesFlag) {
bn, err := parseBootnodes(ctx)
if err != nil {
exit(err)
}
cfg.Bootnodes = bn
}
disc, err := discover.ListenV4(socket, ln, cfg)
if err != nil {
exit(err)
}
return disc
}
func listen() (*net.UDPConn, *enode.LocalNode, discover.Config, error) {
var cfg discover.Config
cfg.PrivateKey, _ = crypto.GenerateKey()
db, _ := enode.OpenDB("")
ln := enode.NewLocalNode(db, cfg.PrivateKey)
socket, err := net.ListenUDP("udp4", &net.UDPAddr{IP: net.IP{0, 0, 0, 0}})
if err != nil {
db.Close()
return nil, nil, cfg, err
}
addr := socket.LocalAddr().(*net.UDPAddr)
ln.SetFallbackIP(net.IP{127, 0, 0, 1})
ln.SetFallbackUDP(addr.Port)
return socket, ln, cfg, nil
}