p2p/enr: initial implementation

This commit is contained in:
Anton Evangelatov 2017-11-28 12:00:32 +01:00 committed by Felix Lange
parent ce823c9f84
commit d94202c943
3 changed files with 618 additions and 0 deletions

396
p2p/enr/enr.go Normal file
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// Copyright 2015 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 discover implements the Ethereum Node Record as per https://github.com/ethereum/EIPs/pull/778
package enr
import (
"bytes"
"crypto/ecdsa"
"encoding/binary"
"errors"
"net"
"sort"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/rlp"
"github.com/btcsuite/btcd/btcec"
)
// The maximum encoded size of a node record is 300 bytes. Implementations should reject records larger than this size.
const (
RECORD_MAX_SIZE = 300
ID_SECP256k1_KECCAK = "secp256k1-keccak" // "secp256k1-keccak" identity scheme identifier
)
// Pseudo-const identifiers for pre-defined keys
var (
ID = []byte(`id`) // name of identity scheme, e.g. "secp256k1-keccak"
SECP256K1 = []byte(`secp256k1`) // compressed secp256k1 public key
IP4 = []byte(`ip4`) // IPv4 address, 4 bytes
IP6 = []byte(`ip6`) // IPv6 address, 16 bytes
DISCV5 = []byte(`discv5`) // UDP port for discovery v5
)
type record struct {
k []byte
v []byte
}
type ENR struct {
seq uint32 // sequence number
signature []byte // record's signature
raw []byte // RLP encoded record
records []record // list of all key/value pairs, sorted prior to RLP encoding
dirty bool // keeps track if record was modified after it was signed and encoded
}
func NewENR() *ENR {
return &ENR{
dirty: true,
}
}
func (e *ENR) GetID() (string, error) {
for _, r := range e.records {
if bytes.Compare(ID, r.k) == 0 {
return string(r.v), nil
}
}
return "", errors.New("id record does not exist")
}
func (e *ENR) SetID(id string) {
e.dirty = true
e.records = append(e.records, record{ID, []byte(id)})
}
func (e *ENR) GetSecp256k1() ([]byte, error) {
for _, r := range e.records {
if bytes.Compare(SECP256K1, r.k) == 0 {
return r.v, nil
}
}
return nil, errors.New("secp256k1 record does not exist")
}
func (e *ENR) SetSecp256k1(pk []byte) {
e.dirty = true
e.records = append(e.records, record{SECP256K1, pk})
}
func (e *ENR) GetIPv4() (net.IP, error) {
for _, r := range e.records {
if bytes.Compare(IP4, r.k) == 0 {
if len(r.v) != net.IPv4len {
return nil, errors.New("wrong ipv4 record length")
}
return net.IP(r.v), nil
}
}
return nil, errors.New("ip4 record does not exist")
}
func (e *ENR) SetIPv4(ip net.IP) error {
e.dirty = true
ipv4 := ip.To4()
if ipv4 == nil {
return errors.New("param is not a valid ipv4 address")
}
e.records = append(e.records, record{IP4, ipv4})
return nil
}
func (e *ENR) GetIPv6() (net.IP, error) {
for _, r := range e.records {
if bytes.Compare(IP6, r.k) == 0 {
if len(r.v) != net.IPv6len {
return nil, errors.New("wrong ipv6 record length")
}
return net.IP(r.v), nil
}
}
return nil, errors.New("ip6 record does not exist")
}
func (e *ENR) SetIPv6(ip net.IP) error {
if len(ip) != net.IPv6len {
return errors.New("param length is not equal to 16 bytes")
}
e.dirty = true
e.records = append(e.records, record{IP6, ip})
return nil
}
func (e *ENR) GetDiscv5() (uint32, error) {
for _, r := range e.records {
if bytes.Compare(DISCV5, r.k) == 0 {
buf := bytes.NewBuffer(r.v)
var port uint32
err := binary.Read(buf, binary.BigEndian, &port)
if err != nil {
return 0, err
}
return port, nil
}
}
return 0, errors.New("secp256k1 record does not exist")
}
func (e *ENR) SetDiscv5(port uint32) error {
e.dirty = true
buf := new(bytes.Buffer)
err := binary.Write(buf, binary.BigEndian, port)
if err != nil {
return err
}
e.records = append(e.records, record{DISCV5, buf.Bytes()})
return nil
}
func (e *ENR) GetRaw(k []byte) ([]byte, error) {
for _, r := range e.records {
if bytes.Compare(r.k, k) == 0 {
return r.v, nil
}
}
return nil, errors.New("record does not exist")
}
func (e *ENR) SetRaw(k []byte, v []byte) {
e.dirty = true
e.records = append(e.records, record{k, v})
}
func (e *ENR) Encode() ([]byte, error) {
if e.dirty {
return nil, errors.New("record is not signed")
}
return e.raw, nil
}
func (e *ENR) NodeAddress() ([]byte, error) {
pk, err := e.GetSecp256k1()
if err != nil {
return nil, err
}
digest := crypto.Keccak256Hash(pk)
return digest.Bytes(), nil
}
func (e *ENR) Decode(data []byte) error {
if len(data) > RECORD_MAX_SIZE {
return errors.New("record is too big")
}
s := rlp.NewStream(bytes.NewReader(data), RECORD_MAX_SIZE)
signature, err := s.Bytes()
if err != nil {
return err
}
// consume the list prefix
_, err = s.List()
if err != nil {
return err
}
seq, err := s.Uint()
if err != nil {
return err
}
var records []record
// read key/value pairs until we reach rlp.EOL
for _, _, err = s.Kind(); err == nil; _, _, err = s.Kind() {
key, err2 := s.Bytes()
if err2 != nil {
return err2
}
value, err2 := s.Bytes()
if err2 != nil {
return err2
}
records = append(records, record{k: key, v: value})
}
if err != rlp.EOL {
return err
}
e.signature = signature
e.raw = data
e.seq = uint32(seq)
e.records = records
err = e.verifySignature()
if err != nil {
return err
}
e.dirty = false
return nil
}
func (e *ENR) Sign(privkey *ecdsa.PrivateKey) error {
e.seq = e.seq + 1
e.SetID(ID_SECP256k1_KECCAK)
pk := (*btcec.PublicKey)(&privkey.PublicKey).SerializeCompressed()
e.SetSecp256k1(pk)
var err error
e.signature, e.raw, err = e.SignAndEncode(privkey)
if err != nil {
return err
}
// mark record ready for encoding
e.dirty = false
return nil
}
func (e *ENR) SignAndEncode(privkey *ecdsa.PrivateKey) ([]byte, []byte, error) {
content, err := e.SerialisedContent()
if err != nil {
return nil, nil, err
}
digest := crypto.Keccak256Hash(content)
signature, err := crypto.Sign(digest.Bytes(), privkey)
if err != nil {
return nil, nil, err
}
blob, err := rlp.EncodeToBytes(signature)
if err != nil {
return nil, nil, err
}
raw := append(blob, content...)
return signature, raw, nil
}
func (e *ENR) SerialisedContent() ([]byte, error) {
var buffer bytes.Buffer
blob, err := rlp.EncodeToBytes(e.seq)
if err != nil {
return nil, err
}
_, err = buffer.Write(blob)
if err != nil {
return nil, err
}
sort.Slice(e.records, func(i, j int) bool {
return bytes.Compare(e.records[i].k, e.records[j].k) < 0
})
for _, r := range e.records {
kk, err := rlp.EncodeToBytes(r.k)
if err != nil {
return nil, err
}
_, err = buffer.Write(kk)
if err != nil {
return nil, err
}
vv, err := rlp.EncodeToBytes(r.v)
if err != nil {
return nil, err
}
_, err = buffer.Write(vv)
if err != nil {
return nil, err
}
}
return wrapList(buffer.Bytes()), nil
}
func (e *ENR) verifySignature() error {
id, err := e.GetID()
if err != nil {
return err
}
// currently "secp256k1-keccak" is the only known identity scheme
if id != ID_SECP256k1_KECCAK {
return errors.New("unknown identity scheme")
}
// get publickey from record
blob, err := e.GetSecp256k1()
if err != nil {
return err
}
pk, err := btcec.ParsePubKey(blob, btcec.S256())
if err != nil {
return err
}
pubkey1 := pk.SerializeUncompressed()
// get publickey from message and signature
content, err := e.SerialisedContent()
if err != nil {
return err
}
digest := crypto.Keccak256Hash(content)
pubkey2, err := crypto.Ecrecover(digest.Bytes(), e.signature)
if err != nil {
return err
}
if bytes.Compare(pubkey1, pubkey2) != 0 {
return errors.New("public key mismatch")
}
return nil
}
func wrapList(c []byte) []byte {
head := make([]byte, 9)
res := rlp.LengthPrefix(head, uint64(len(c)))
return append(res, c...)
}

218
p2p/enr/enr_test.go Normal file
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// Copyright 2015 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 enr
import (
"bytes"
"encoding/hex"
"net"
"reflect"
"testing"
"github.com/btcsuite/btcd/btcec"
"github.com/ethereum/go-ethereum/crypto"
)
const (
privkeyHex = "b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291"
)
func TestGetSetID(t *testing.T) {
id := "someid"
e := NewENR()
e.SetID(id)
got, err := e.GetID()
if err != nil {
t.Fatalf("error: %#v", err)
}
if got != id {
t.Fatalf("got %#v, expected %#v", got, id)
}
}
func TestGetSetIP4(t *testing.T) {
ip := net.IP{192, 168, 0, 3}
e := NewENR()
e.SetIPv4(ip)
got, err := e.GetIPv4()
if err != nil {
t.Fatalf("error: %#v", err)
}
if !got.Equal(ip) {
t.Fatalf("got %#v, expected %#v", got, ip)
}
}
func TestGetSetIP6(t *testing.T) {
ip := net.IP{0x20, 0x01, 0x48, 0x60, 0, 0, 0x20, 0x01, 0, 0, 0, 0, 0, 0, 0x00, 0x68}
e := NewENR()
e.SetIPv6(ip)
got, err := e.GetIPv6()
if err != nil {
t.Fatalf("error: %#v", err)
}
if !got.Equal(ip) {
t.Fatalf("got %#v, expected %#v", got, ip)
}
}
func TestGetSetDiscv5(t *testing.T) {
port := uint32(30309)
e := NewENR()
err := e.SetDiscv5(port)
if err != nil {
t.Fatalf("error: %#v", err)
}
got, err := e.GetDiscv5()
if err != nil {
t.Fatalf("error: %#v", err)
}
if got != port {
t.Fatalf("got %#v, expected %#v", got, port)
}
}
func TestGetSetSecp256k1(t *testing.T) {
privkey, err := crypto.HexToECDSA(privkeyHex)
if err != nil {
t.Fatalf("error: %#v", err)
}
e := NewENR()
err = e.Sign(privkey)
if err != nil {
t.Fatalf("error: %#v", err)
}
got, err := e.GetSecp256k1()
if err != nil {
t.Fatalf("error: %#v", err)
}
expected := (*btcec.PublicKey)(&privkey.PublicKey).SerializeCompressed()
if bytes.Compare(got, expected) != 0 {
t.Fatalf("got %#v, expected %#v", got, expected)
}
}
func TestDirty(t *testing.T) {
privkey, err := crypto.HexToECDSA(privkeyHex)
if err != nil {
t.Fatalf("error: %#v", err)
}
e := NewENR()
err = e.Sign(privkey)
if err != nil {
t.Fatalf("error: %#v", err)
}
if _, err := e.Encode(); err != nil {
t.Fatalf("error: %#v", err)
}
e.SetRaw([]byte(`some key`), []byte(`some value`))
if _, err := e.Encode(); err == nil {
t.Fatal("expected err, got nil")
}
}
func TestSignEncodeAndDecode(t *testing.T) {
privkey, err := crypto.HexToECDSA(privkeyHex)
if err != nil {
t.Fatal(err)
}
e := NewENR()
e.SetDiscv5(30303)
e.SetIPv4(net.ParseIP("127.0.0.1"))
err = e.Sign(privkey)
if err != nil {
t.Fatal(err)
}
record, err := e.Encode()
if err != nil {
t.Fatal(err)
}
e2 := NewENR()
err = e2.Decode(record)
if err != nil {
t.Fatal(err)
}
if !reflect.DeepEqual(e, e2) {
t.Errorf("got\n%#v, expected\n%#v", e2, e)
}
expectedRecord := "b8415571f9a36b1e26c366745894656dd1565033cdeda18d330c9a9bac67dfc3e786556b0490e509372fa9db5abf418accd895467e8ff047bbdc147789bef71a2cc401f8560186646973637635840000765f82696490736563703235366b312d6b656363616b83697034847f00000189736563703235366b31a103ca634cae0d49acb401d8a4c6b6fe8c55b70d115bf400769cc1400f3258cd3138"
got := hex.EncodeToString(record)
if got != expectedRecord {
t.Errorf("got\n%#v, expected\n%#v", got, expectedRecord)
}
blob, err := e2.Encode()
if err != nil {
t.Fatal(err)
}
got = hex.EncodeToString(blob)
if got != expectedRecord {
t.Errorf("got\n%#v, expected\n%#v", got, expectedRecord)
}
}
func TestNodeAddress(t *testing.T) {
privkey, err := crypto.HexToECDSA(privkeyHex)
if err != nil {
t.Fatal(err)
}
e := NewENR()
err = e.Sign(privkey)
if err != nil {
t.Fatal(err)
}
addr, err := e.NodeAddress()
if err != nil {
t.Fatal(err)
}
expected := "caaa1485d83b18b32ed9ad666026151bf0cae8a0a88c857ae2d4c5be2daa6726"
got := hex.EncodeToString(addr)
if got != expected {
t.Errorf("got\n%#v, expected\n%#v", got, expected)
}
}

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@ -136,6 +136,10 @@ func (head *listhead) encode(buf []byte) []byte {
return buf[:puthead(buf, 0xC0, 0xF7, uint64(head.size))] return buf[:puthead(buf, 0xC0, 0xF7, uint64(head.size))]
} }
func LengthPrefix(buf []byte, size uint64) []byte {
return buf[:puthead(buf, 0xC0, 0xF7, size)]
}
// headsize returns the size of a list or string header // headsize returns the size of a list or string header
// for a value of the given size. // for a value of the given size.
func headsize(size uint64) int { func headsize(size uint64) int {