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// Copyright 2018 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 external
import (
"fmt"
"math/big"
"sync"
"github.com/ethereum/go-ethereum"
"github.com/ethereum/go-ethereum/accounts"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/hexutil"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/event"
"github.com/ethereum/go-ethereum/internal/ethapi"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/rpc"
"github.com/ethereum/go-ethereum/signer/core"
)
type ExternalBackend struct {
signers []accounts.Wallet
}
func (eb *ExternalBackend) Wallets() []accounts.Wallet {
return eb.signers
}
func NewExternalBackend(endpoint string) (*ExternalBackend, error) {
signer, err := NewExternalSigner(endpoint)
if err != nil {
return nil, err
}
return &ExternalBackend{
signers: []accounts.Wallet{signer},
}, nil
}
func (eb *ExternalBackend) Subscribe(sink chan<- accounts.WalletEvent) event.Subscription {
return event.NewSubscription(func(quit <-chan struct{}) error {
<-quit
return nil
})
}
// ExternalSigner provides an API to interact with an external signer (clef)
// It proxies request to the external signer while forwarding relevant
// request headers
type ExternalSigner struct {
client *rpc.Client
endpoint string
status string
cacheMu sync.RWMutex
cache []accounts.Account
}
func NewExternalSigner(endpoint string) (*ExternalSigner, error) {
client, err := rpc.Dial(endpoint)
if err != nil {
return nil, err
}
extsigner := &ExternalSigner{
client: client,
endpoint: endpoint,
}
// Check if reachable
version, err := extsigner.pingVersion()
if err != nil {
return nil, err
}
extsigner.status = fmt.Sprintf("ok [version=%v]", version)
return extsigner, nil
}
func (api *ExternalSigner) URL() accounts.URL {
return accounts.URL{
Scheme: "extapi",
Path: api.endpoint,
}
}
func (api *ExternalSigner) Status() (string, error) {
return api.status, nil
}
func (api *ExternalSigner) Open(passphrase string) error {
return fmt.Errorf("operation not supported on external signers")
}
func (api *ExternalSigner) Close() error {
return fmt.Errorf("operation not supported on external signers")
}
func (api *ExternalSigner) Accounts() []accounts.Account {
var accnts []accounts.Account
res, err := api.listAccounts()
if err != nil {
log.Error("account listing failed", "error", err)
return accnts
}
for _, addr := range res {
accnts = append(accnts, accounts.Account{
URL: accounts.URL{
Scheme: "extapi",
Path: api.endpoint,
},
Address: addr,
})
}
api.cacheMu.Lock()
api.cache = accnts
api.cacheMu.Unlock()
return accnts
}
func (api *ExternalSigner) Contains(account accounts.Account) bool {
api.cacheMu.RLock()
defer api.cacheMu.RUnlock()
for _, a := range api.cache {
if a.Address == account.Address && (account.URL == (accounts.URL{}) || account.URL == api.URL()) {
return true
}
}
return false
}
func (api *ExternalSigner) Derive(path accounts.DerivationPath, pin bool) (accounts.Account, error) {
return accounts.Account{}, fmt.Errorf("operation not supported on external signers")
}
func (api *ExternalSigner) SelfDerive(base accounts.DerivationPath, chain ethereum.ChainStateReader) {
log.Error("operation SelfDerive not supported on external signers")
}
func (api *ExternalSigner) signHash(account accounts.Account, hash []byte) ([]byte, error) {
return []byte{}, fmt.Errorf("operation not supported on external signers")
}
// SignData signs keccak256(data). The mimetype parameter describes the type of data being signed
func (api *ExternalSigner) SignData(account accounts.Account, mimeType string, data []byte) ([]byte, error) {
// TODO! Replace this with a call to clef SignData with correct mime-type for Clique, once we
// have that in place
return api.signHash(account, crypto.Keccak256(data))
}
func (api *ExternalSigner) SignText(account accounts.Account, text []byte) ([]byte, error) {
return api.signHash(account, accounts.TextHash(text))
}
func (api *ExternalSigner) SignTx(account accounts.Account, tx *types.Transaction, chainID *big.Int) (*types.Transaction, error) {
res := ethapi.SignTransactionResult{}
to := common.NewMixedcaseAddress(*tx.To())
data := hexutil.Bytes(tx.Data())
args := &core.SendTxArgs{
Data: &data,
Nonce: hexutil.Uint64(tx.Nonce()),
Value: hexutil.Big(*tx.Value()),
Gas: hexutil.Uint64(tx.Gas()),
GasPrice: hexutil.Big(*tx.GasPrice()),
To: &to,
From: common.NewMixedcaseAddress(account.Address),
}
if err := api.client.Call(&res, "account_signTransaction", args); err != nil {
return nil, err
}
return res.Tx, nil
}
func (api *ExternalSigner) SignTextWithPassphrase(account accounts.Account, passphrase string, text []byte) ([]byte, error) {
return []byte{}, fmt.Errorf("passphrase-operations not supported on external signers")
}
func (api *ExternalSigner) SignTxWithPassphrase(account accounts.Account, passphrase string, tx *types.Transaction, chainID *big.Int) (*types.Transaction, error) {
return nil, fmt.Errorf("passphrase-operations not supported on external signers")
}
func (api *ExternalSigner) SignDataWithPassphrase(account accounts.Account, passphrase, mimeType string, data []byte) ([]byte, error) {
return nil, fmt.Errorf("passphrase-operations not supported on external signers")
}
func (api *ExternalSigner) listAccounts() ([]common.Address, error) {
var res []common.Address
if err := api.client.Call(&res, "account_list"); err != nil {
return nil, err
}
return res, nil
}
func (api *ExternalSigner) signCliqueBlock(a common.Address, rlpBlock hexutil.Bytes) (hexutil.Bytes, error) {
var sig hexutil.Bytes
if err := api.client.Call(&sig, "account_signData", core.ApplicationClique.Mime, a, rlpBlock); err != nil {
return nil, err
}
if sig[64] != 27 && sig[64] != 28 {
return nil, fmt.Errorf("invalid Ethereum signature (V is not 27 or 28)")
}
sig[64] -= 27 // Transform V from 27/28 to 0/1 for Clique use
return sig, nil
}
func (api *ExternalSigner) pingVersion() (string, error) {
var v string
if err := api.client.Call(&v, "account_version"); err != nil {
return "", err
}
return v, nil
}
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