// Copyright 2018 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library 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 Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package enode
import (
"crypto/ecdsa"
"encoding/hex"
"errors"
"fmt"
"net"
"net/url"
"regexp"
"strconv"
"github.com/dexon-foundation/dexon/common/math"
"github.com/dexon-foundation/dexon/crypto"
"github.com/dexon-foundation/dexon/p2p/enr"
)
var incompleteNodeURL = regexp.MustCompile("(?i)^(?:enode://)?([0-9a-f]+)$")
// MustParseV4 parses a node URL. It panics if the URL is not valid.
func MustParseV4(rawurl string) *Node {
n, err := ParseV4(rawurl)
if err != nil {
panic("invalid node URL: " + err.Error())
}
return n
}
// ParseV4 parses a node URL.
//
// There are two basic forms of node URLs:
//
// - incomplete nodes, which only have the public key (node ID)
// - complete nodes, which contain the public key and IP/Port information
//
// For incomplete nodes, the designator must look like one of these
//
// enode://<hex node id>
// <hex node id>
//
// For complete nodes, the node ID is encoded in the username portion
// of the URL, separated from the host by an @ sign. The hostname can
// only be given as an IP address, DNS domain names are not allowed.
// The port in the host name section is the TCP listening port. If the
// TCP and UDP (discovery) ports differ, the UDP port is specified as
// query parameter "discport".
//
// In the following example, the node URL describes
// a node with IP address 10.3.58.6, TCP listening port 30303
// and UDP discovery port 30301.
//
// enode://<hex node id>@10.3.58.6:30303?discport=30301
func ParseV4(rawurl string) (*Node, error) {
if m := incompleteNodeURL.FindStringSubmatch(rawurl); m != nil {
id, err := parsePubkey(m[1])
if err != nil {
return nil, fmt.Errorf("invalid node ID (%v)", err)
}
return NewV4(id, nil, 0, 0), nil
}
return parseComplete(rawurl)
}
// NewV4 creates a node from discovery v4 node information. The record
// contained in the node has a zero-length signature.
func NewV4(pubkey *ecdsa.PublicKey, ip net.IP, tcp, udp int) *Node {
var r enr.Record
if ip != nil {
r.Set(enr.IP(ip))
}
if udp != 0 {
r.Set(enr.UDP(udp))
}
if tcp != 0 {
r.Set(enr.TCP(tcp))
}
signV4Compat(&r, pubkey)
n, err := New(v4CompatID{}, &r)
if err != nil {
panic(err)
}
return n
}
func parseComplete(rawurl string) (*Node, error) {
var (
id *ecdsa.PublicKey
ip net.IP
tcpPort, udpPort uint64
)
u, err := url.Parse(rawurl)
if err != nil {
return nil, err
}
if u.Scheme != "enode" {
return nil, errors.New("invalid URL scheme, want \"enode\"")
}
// Parse the Node ID from the user portion.
if u.User == nil {
return nil, errors.New("does not contain node ID")
}
if id, err = parsePubkey(u.User.String()); err != nil {
return nil, fmt.Errorf("invalid node ID (%v)", err)
}
// Parse the IP address.
host, port, err := net.SplitHostPort(u.Host)
if err != nil {
return nil, fmt.Errorf("invalid host: %v", err)
}
if ip = net.ParseIP(host); ip == nil {
return nil, errors.New("invalid IP address")
}
// Ensure the IP is 4 bytes long for IPv4 addresses.
if ipv4 := ip.To4(); ipv4 != nil {
ip = ipv4
}
// Parse the port numbers.
if tcpPort, err = strconv.ParseUint(port, 10, 16); err != nil {
return nil, errors.New("invalid port")
}
udpPort = tcpPort
qv := u.Query()
if qv.Get("discport") != "" {
udpPort, err = strconv.ParseUint(qv.Get("discport"), 10, 16)
if err != nil {
return nil, errors.New("invalid discport in query")
}
}
return NewV4(id, ip, int(tcpPort), int(udpPort)), nil
}
// parsePubkey parses a hex-encoded secp256k1 public key.
func parsePubkey(in string) (*ecdsa.PublicKey, error) {
b, err := hex.DecodeString(in)
if err != nil {
return nil, err
} else if len(b) != 64 {
return nil, fmt.Errorf("wrong length, want %d hex chars", 128)
}
b = append([]byte{0x4}, b...)
return crypto.UnmarshalPubkey(b)
}
func (n *Node) v4URL() string {
var (
scheme enr.ID
nodeid string
key ecdsa.PublicKey
)
n.Load(&scheme)
n.Load((*Secp256k1)(&key))
switch {
case scheme == "v4" || key != ecdsa.PublicKey{}:
nodeid = fmt.Sprintf("%x", crypto.FromECDSAPub(&key)[1:])
default:
nodeid = fmt.Sprintf("%s.%x", scheme, n.id[:])
}
u := url.URL{Scheme: "enode"}
if n.Incomplete() {
u.Host = nodeid
} else {
addr := net.TCPAddr{IP: n.IP(), Port: n.TCP()}
u.User = url.User(nodeid)
u.Host = addr.String()
if n.UDP() != n.TCP() {
u.RawQuery = "discport=" + strconv.Itoa(n.UDP())
}
}
return u.String()
}
// PubkeyToIDV4 derives the v4 node address from the given public key.
func PubkeyToIDV4(key *ecdsa.PublicKey) ID {
e := make([]byte, 64)
math.ReadBits(key.X, e[:len(e)/2])
math.ReadBits(key.Y, e[len(e)/2:])
return ID(crypto.Keccak256Hash(e))
}
