cmd/devp2p: add commands for node key management (#21202)

These commands mirror the key/URL generation functions of cmd/bootnode.

    $ devp2p key generate mynode.key
    $ devp2p key to-enode mynode.key -ip 203.0.113.21 -tcp 30304
    enode://78a7746089baf4b8615f54a5f0b67b22b1...

cmd/devp2p/keycmd.go

@@ -0,0 +1,105 @@
+// Copyright 2020 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"
+
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/p2p/enode"
+	"gopkg.in/urfave/cli.v1"
+)
+
+var (
+	keyCommand = cli.Command{
+		Name:  "key",
+		Usage: "Operations on node keys",
+		Subcommands: []cli.Command{
+			keyGenerateCommand,
+			keyToNodeCommand,
+		},
+	}
+	keyGenerateCommand = cli.Command{
+		Name:      "generate",
+		Usage:     "Generates node key files",
+		ArgsUsage: "keyfile",
+		Action:    genkey,
+	}
+	keyToNodeCommand = cli.Command{
+		Name:      "to-enode",
+		Usage:     "Creates an enode URL from a node key file",
+		ArgsUsage: "keyfile",
+		Action:    keyToURL,
+		Flags:     []cli.Flag{hostFlag, tcpPortFlag, udpPortFlag},
+	}
+)
+
+var (
+	hostFlag = cli.StringFlag{
+		Name:  "ip",
+		Usage: "IP address of the node",
+		Value: "127.0.0.1",
+	}
+	tcpPortFlag = cli.IntFlag{
+		Name:  "tcp",
+		Usage: "TCP port of the node",
+		Value: 30303,
+	}
+	udpPortFlag = cli.IntFlag{
+		Name:  "udp",
+		Usage: "UDP port of the node",
+		Value: 30303,
+	}
+)
+
+func genkey(ctx *cli.Context) error {
+	if ctx.NArg() != 1 {
+		return fmt.Errorf("need key file as argument")
+	}
+	file := ctx.Args().Get(0)
+
+	key, err := crypto.GenerateKey()
+	if err != nil {
+		return fmt.Errorf("could not generate key: %v", err)
+	}
+	return crypto.SaveECDSA(file, key)
+}
+
+func keyToURL(ctx *cli.Context) error {
+	if ctx.NArg() != 1 {
+		return fmt.Errorf("need key file as argument")
+	}
+
+	var (
+		file = ctx.Args().Get(0)
+		host = ctx.String(hostFlag.Name)
+		tcp  = ctx.Int(tcpPortFlag.Name)
+		udp  = ctx.Int(udpPortFlag.Name)
+	)
+	key, err := crypto.LoadECDSA(file)
+	if err != nil {
+		return err
+	}
+	ip := net.ParseIP(host)
+	if ip == nil {
+		return fmt.Errorf("invalid IP address %q", host)
+	}
+	node := enode.NewV4(&key.PublicKey, ip, tcp, udp)
+	fmt.Println(node.URLv4())
+	return nil
+}

cmd/devp2p/main.go

@@ -58,6 +58,7 @@ func init() {
 	// Add subcommands.
 	app.Commands = []cli.Command{
 		enrdumpCommand,
+		keyCommand,
 		discv4Command,
 		discv5Command,
 		dnsCommand,