Official Go implementation of the Ethereum protocol
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go-ethereum/cmd/devp2p/enrcmd.go

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5.2 KiB

// 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 (
"bytes"
"encoding/base64"
"encoding/hex"
"fmt"
"io"
"net"
"os"
"strconv"
"strings"
"github.com/ethereum/go-ethereum/p2p/enode"
"github.com/ethereum/go-ethereum/p2p/enr"
"github.com/ethereum/go-ethereum/rlp"
"gopkg.in/urfave/cli.v1"
)
var fileFlag = cli.StringFlag{Name: "file"}
var enrdumpCommand = cli.Command{
Name: "enrdump",
Usage: "Pretty-prints node records",
Action: enrdump,
Flags: []cli.Flag{
fileFlag,
},
}
func enrdump(ctx *cli.Context) error {
var source string
if file := ctx.String(fileFlag.Name); file != "" {
if ctx.NArg() != 0 {
return fmt.Errorf("can't dump record from command-line argument in -file mode")
}
var b []byte
var err error
if file == "-" {
b, err = io.ReadAll(os.Stdin)
} else {
b, err = os.ReadFile(file)
}
if err != nil {
return err
}
source = string(b)
} else if ctx.NArg() == 1 {
source = ctx.Args()[0]
} else {
return fmt.Errorf("need record as argument")
}
r, err := parseRecord(source)
if err != nil {
return fmt.Errorf("INVALID: %v", err)
}
dumpRecord(os.Stdout, r)
return nil
}
// dumpRecord creates a human-readable description of the given node record.
func dumpRecord(out io.Writer, r *enr.Record) {
n, err := enode.New(enode.ValidSchemes, r)
if err != nil {
fmt.Fprintf(out, "INVALID: %v\n", err)
} else {
fmt.Fprintf(out, "Node ID: %v\n", n.ID())
dumpNodeURL(out, n)
}
kv := r.AppendElements(nil)[1:]
fmt.Fprintf(out, "Record has sequence number %d and %d key/value pairs.\n", r.Seq(), len(kv)/2)
fmt.Fprint(out, dumpRecordKV(kv, 2))
}
func dumpNodeURL(out io.Writer, n *enode.Node) {
var key enode.Secp256k1
if n.Load(&key) != nil {
return // no secp256k1 public key
}
fmt.Fprintf(out, "URLv4: %s\n", n.URLv4())
}
func dumpRecordKV(kv []interface{}, indent int) string {
// Determine the longest key name for alignment.
var out string
var longestKey = 0
for i := 0; i < len(kv); i += 2 {
key := kv[i].(string)
if len(key) > longestKey {
longestKey = len(key)
}
}
// Print the keys, invoking formatters for known keys.
for i := 0; i < len(kv); i += 2 {
key := kv[i].(string)
val := kv[i+1].(rlp.RawValue)
pad := longestKey - len(key)
out += strings.Repeat(" ", indent) + strconv.Quote(key) + strings.Repeat(" ", pad+1)
formatter := attrFormatters[key]
if formatter == nil {
formatter = formatAttrRaw
}
fmtval, ok := formatter(val)
if ok {
out += fmtval + "\n"
} else {
out += hex.EncodeToString(val) + " (!)\n"
}
}
return out
}
// parseNode parses a node record and verifies its signature.
func parseNode(source string) (*enode.Node, error) {
if strings.HasPrefix(source, "enode://") {
return enode.ParseV4(source)
}
r, err := parseRecord(source)
if err != nil {
return nil, err
}
return enode.New(enode.ValidSchemes, r)
}
// parseRecord parses a node record from hex, base64, or raw binary input.
func parseRecord(source string) (*enr.Record, error) {
bin := []byte(source)
if d, ok := decodeRecordHex(bytes.TrimSpace(bin)); ok {
bin = d
} else if d, ok := decodeRecordBase64(bytes.TrimSpace(bin)); ok {
bin = d
}
var r enr.Record
err := rlp.DecodeBytes(bin, &r)
return &r, err
}
func decodeRecordHex(b []byte) ([]byte, bool) {
if bytes.HasPrefix(b, []byte("0x")) {
b = b[2:]
}
dec := make([]byte, hex.DecodedLen(len(b)))
_, err := hex.Decode(dec, b)
return dec, err == nil
}
func decodeRecordBase64(b []byte) ([]byte, bool) {
if bytes.HasPrefix(b, []byte("enr:")) {
b = b[4:]
}
dec := make([]byte, base64.RawURLEncoding.DecodedLen(len(b)))
n, err := base64.RawURLEncoding.Decode(dec, b)
return dec[:n], err == nil
}
// attrFormatters contains formatting functions for well-known ENR keys.
var attrFormatters = map[string]func(rlp.RawValue) (string, bool){
"id": formatAttrString,
"ip": formatAttrIP,
"ip6": formatAttrIP,
"tcp": formatAttrUint,
"tcp6": formatAttrUint,
"udp": formatAttrUint,
"udp6": formatAttrUint,
}
func formatAttrRaw(v rlp.RawValue) (string, bool) {
s := hex.EncodeToString(v)
return s, true
}
func formatAttrString(v rlp.RawValue) (string, bool) {
content, _, err := rlp.SplitString(v)
return strconv.Quote(string(content)), err == nil
}
func formatAttrIP(v rlp.RawValue) (string, bool) {
content, _, err := rlp.SplitString(v)
if err != nil || len(content) != 4 && len(content) != 6 {
return "", false
}
return net.IP(content).String(), true
}
func formatAttrUint(v rlp.RawValue) (string, bool) {
var x uint64
if err := rlp.DecodeBytes(v, &x); err != nil {
return "", false
}
return strconv.FormatUint(x, 10), true
}