accounts: refactor API for generalized USB wallets

1 files changed, 0 insertions, 898 deletions

diff --git a/accounts/usbwallet/ledger_wallet.go b/accounts/usbwallet/ledger_wallet.go
deleted file mode 100644
index b8f04d74c..000000000
--- a/accounts/usbwallet/ledger_wallet.go
+++ /dev/null
@@ -1,898 +0,0 @@
-// Copyright 2017 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/>.
-
-// This file contains the implementation for interacting with the Ledger hardware
-// wallets. The wire protocol spec can be found in the Ledger Blue GitHub repo:
-// https://raw.githubusercontent.com/LedgerHQ/blue-app-eth/master/doc/ethapp.asc
-
-package usbwallet
-
-import (
-	"context"
-	"encoding/binary"
-	"encoding/hex"
-	"errors"
-	"fmt"
-	"io"
-	"math/big"
-	"sync"
-	"time"
-
-	ethereum "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/log"
-	"github.com/ethereum/go-ethereum/rlp"
-	"github.com/karalabe/hid"
-)
-
-// ledgerOpcode is an enumeration encoding the supported Ledger opcodes.
-type ledgerOpcode byte
-
-// ledgerParam1 is an enumeration encoding the supported Ledger parameters for
-// specific opcodes. The same parameter values may be reused between opcodes.
-type ledgerParam1 byte
-
-// ledgerParam2 is an enumeration encoding the supported Ledger parameters for
-// specific opcodes. The same parameter values may be reused between opcodes.
-type ledgerParam2 byte
-
-const (
-	ledgerOpRetrieveAddress  ledgerOpcode = 0x02 // Returns the public key and Ethereum address for a given BIP 32 path
-	ledgerOpSignTransaction  ledgerOpcode = 0x04 // Signs an Ethereum transaction after having the user validate the parameters
-	ledgerOpGetConfiguration ledgerOpcode = 0x06 // Returns specific wallet application configuration
-
-	ledgerP1DirectlyFetchAddress    ledgerParam1 = 0x00 // Return address directly from the wallet
-	ledgerP1ConfirmFetchAddress     ledgerParam1 = 0x01 // Require a user confirmation before returning the address
-	ledgerP1InitTransactionData     ledgerParam1 = 0x00 // First transaction data block for signing
-	ledgerP1ContTransactionData     ledgerParam1 = 0x80 // Subsequent transaction data block for signing
-	ledgerP2DiscardAddressChainCode ledgerParam2 = 0x00 // Do not return the chain code along with the address
-	ledgerP2ReturnAddressChainCode  ledgerParam2 = 0x01 // Require a user confirmation before returning the address
-)
-
-// errReplyInvalidHeader is the error message returned by a Ledger data exchange
-// if the device replies with a mismatching header. This usually means the device
-// is in browser mode.
-var errReplyInvalidHeader = errors.New("invalid reply header")
-
-// errInvalidVersionReply is the error message returned by a Ledger version retrieval
-// when a response does arrive, but it does not contain the expected data.
-var errInvalidVersionReply = errors.New("invalid version reply")
-
-// ledgerWallet represents a live USB Ledger hardware wallet.
-type ledgerWallet struct {
-	hub *LedgerHub    // USB hub the device originates from (TODO(karalabe): remove if hotplug lands on Windows)
-	url *accounts.URL // Textual URL uniquely identifying this wallet
-
-	info    hid.DeviceInfo // Known USB device infos about the wallet
-	device  *hid.Device    // USB device advertising itself as a Ledger wallet
-	failure error          // Any failure that would make the device unusable
-
-	version  [3]byte                                    // Current version of the Ledger Ethereum app (zero if app is offline)
-	browser  bool                                       // Flag whether the Ledger is in browser mode (reply channel mismatch)
-	accounts []accounts.Account                         // List of derive accounts pinned on the Ledger
-	paths    map[common.Address]accounts.DerivationPath // Known derivation paths for signing operations
-
-	deriveNextPath accounts.DerivationPath   // Next derivation path for account auto-discovery
-	deriveNextAddr common.Address            // Next derived account address for auto-discovery
-	deriveChain    ethereum.ChainStateReader // Blockchain state reader to discover used account with
-	deriveReq      chan chan struct{}        // Channel to request a self-derivation on
-	deriveQuit     chan chan error           // Channel to terminate the self-deriver with
-
-	healthQuit chan chan error
-
-	// Locking a hardware wallet is a bit special. Since hardware devices are lower
-	// performing, any communication with them might take a non negligible amount of
-	// time. Worse still, waiting for user confirmation can take arbitrarily long,
-	// but exclusive communication must be upheld during. Locking the entire wallet
-	// in the mean time however would stall any parts of the system that don't want
-	// to communicate, just read some state (e.g. list the accounts).
-	//
-	// As such, a hardware wallet needs two locks to function correctly. A state
-	// lock can be used to protect the wallet's software-side internal state, which
-	// must not be held exlusively during hardware communication. A communication
-	// lock can be used to achieve exclusive access to the device itself, this one
-	// however should allow "skipping" waiting for operations that might want to
-	// use the device, but can live without too (e.g. account self-derivation).
-	//
-	// Since we have two locks, it's important to know how to properly use them:
-	//   - Communication requires the `device` to not change, so obtaining the
-	//     commsLock should be done after having a stateLock.
-	//   - Communication must not disable read access to the wallet state, so it
-	//     must only ever hold a *read* lock to stateLock.
-	commsLock chan struct{} // Mutex (buf=1) for the USB comms without keeping the state locked
-	stateLock sync.RWMutex  // Protects read and write access to the wallet struct fields
-
-	log log.Logger // Contextual logger to tag the ledger with its id
-}
-
-// URL implements accounts.Wallet, returning the URL of the Ledger device.
-func (w *ledgerWallet) URL() accounts.URL {
-	return *w.url // Immutable, no need for a lock
-}
-
-// Status implements accounts.Wallet, always whether the Ledger is opened, closed
-// or whether the Ethereum app was not started on it.
-func (w *ledgerWallet) Status() string {
-	w.stateLock.RLock() // No device communication, state lock is enough
-	defer w.stateLock.RUnlock()
-
-	if w.failure != nil {
-		return fmt.Sprintf("Failed: %v", w.failure)
-	}
-	if w.device == nil {
-		return "Closed"
-	}
-	if w.browser {
-		return "Ethereum app in browser mode"
-	}
-	if w.offline() {
-		return "Ethereum app offline"
-	}
-	return fmt.Sprintf("Ethereum app v%d.%d.%d online", w.version[0], w.version[1], w.version[2])
-}
-
-// offline returns whether the wallet and the Ethereum app is offline or not.
-//
-// The method assumes that the state lock is held!
-func (w *ledgerWallet) offline() bool {
-	return w.version == [3]byte{0, 0, 0}
-}
-
-// failed returns if the USB device wrapped by the wallet failed for some reason.
-// This is used by the device scanner to report failed wallets as departed.
-//
-// The method assumes that the state lock is *not* held!
-func (w *ledgerWallet) failed() bool {
-	w.stateLock.RLock() // No device communication, state lock is enough
-	defer w.stateLock.RUnlock()
-
-	return w.failure != nil
-}
-
-// Open implements accounts.Wallet, attempting to open a USB connection to the
-// Ledger hardware wallet. The Ledger does not require a user passphrase, so that
-// parameter is silently discarded.
-func (w *ledgerWallet) Open(passphrase string) error {
-	w.stateLock.Lock() // State lock is enough since there's no connection yet at this point
-	defer w.stateLock.Unlock()
-
-	// If the wallet was already opened, don't try to open again
-	if w.device != nil {
-		return accounts.ErrWalletAlreadyOpen
-	}
-	// Otherwise iterate over all USB devices and find this again (no way to directly do this)
-	device, err := w.info.Open()
-	if err != nil {
-		return err
-	}
-	// Wallet seems to be successfully opened, guess if the Ethereum app is running
-	w.device = device
-	w.commsLock = make(chan struct{}, 1)
-	w.commsLock <- struct{}{} // Enable lock
-
-	w.paths = make(map[common.Address]accounts.DerivationPath)
-
-	w.deriveReq = make(chan chan struct{})
-	w.deriveQuit = make(chan chan error)
-	w.healthQuit = make(chan chan error)
-
-	defer func() {
-		go w.heartbeat()
-		go w.selfDerive()
-	}()
-
-	if _, err = w.ledgerDerive(accounts.DefaultBaseDerivationPath); err != nil {
-		// Ethereum app is not running or in browser mode, nothing more to do, return
-		if err == errReplyInvalidHeader {
-			w.browser = true
-		}
-		return nil
-	}
-	// Try to resolve the Ethereum app's version, will fail prior to v1.0.2
-	if w.version, err = w.ledgerVersion(); err != nil {
-		w.version = [3]byte{1, 0, 0} // Assume worst case, can't verify if v1.0.0 or v1.0.1
-	}
-	go w.hub.updateFeed.Send(accounts.WalletEvent{Wallet: w, Kind: accounts.WalletOpened})
-
-	return nil
-}
-
-// heartbeat is a health check loop for the Ledger wallets to periodically verify
-// whether they are still present or if they malfunctioned. It is needed because:
-//  - libusb on Windows doesn't support hotplug, so we can't detect USB unplugs
-//  - communication timeout on the Ledger requires a device power cycle to fix
-func (w *ledgerWallet) heartbeat() {
-	w.log.Debug("Ledger health-check started")
-	defer w.log.Debug("Ledger health-check stopped")
-
-	// Execute heartbeat checks until termination or error
-	var (
-		errc chan error
-		err  error
-	)
-	for errc == nil && err == nil {
-		// Wait until termination is requested or the heartbeat cycle arrives
-		select {
-		case errc = <-w.healthQuit:
-			// Termination requested
-			continue
-		case <-time.After(heartbeatCycle):
-			// Heartbeat time
-		}
-		// Execute a tiny data exchange to see responsiveness
-		w.stateLock.RLock()
-		if w.device == nil {
-			// Terminated while waiting for the lock
-			w.stateLock.RUnlock()
-			continue
-		}
-		<-w.commsLock // Don't lock state while resolving version
-		_, err = w.ledgerVersion()
-		w.commsLock <- struct{}{}
-		w.stateLock.RUnlock()
-
-		if err != nil && err != errInvalidVersionReply {
-			w.stateLock.Lock() // Lock state to tear the wallet down
-			w.failure = err
-			w.close()
-			w.stateLock.Unlock()
-		}
-		// Ignore non hardware related errors
-		err = nil
-	}
-	// In case of error, wait for termination
-	if err != nil {
-		w.log.Debug("Ledger health-check failed", "err", err)
-		errc = <-w.healthQuit
-	}
-	errc <- err
-}
-
-// Close implements accounts.Wallet, closing the USB connection to the Ledger.
-func (w *ledgerWallet) Close() error {
-	// Ensure the wallet was opened
-	w.stateLock.RLock()
-	hQuit, dQuit := w.healthQuit, w.deriveQuit
-	w.stateLock.RUnlock()
-
-	// Terminate the health checks
-	var herr error
-	if hQuit != nil {
-		errc := make(chan error)
-		hQuit <- errc
-		herr = <-errc // Save for later, we *must* close the USB
-	}
-	// Terminate the self-derivations
-	var derr error
-	if dQuit != nil {
-		errc := make(chan error)
-		dQuit <- errc
-		derr = <-errc // Save for later, we *must* close the USB
-	}
-	// Terminate the device connection
-	w.stateLock.Lock()
-	defer w.stateLock.Unlock()
-
-	w.healthQuit = nil
-	w.deriveQuit = nil
-	w.deriveReq = nil
-
-	if err := w.close(); err != nil {
-		return err
-	}
-	if herr != nil {
-		return herr
-	}
-	return derr
-}
-
-// close is the internal wallet closer that terminates the USB connection and
-// resets all the fields to their defaults.
-//
-// Note, close assumes the state lock is held!
-func (w *ledgerWallet) close() error {
-	// Allow duplicate closes, especially for health-check failures
-	if w.device == nil {
-		return nil
-	}
-	// Close the device, clear everything, then return
-	w.device.Close()
-	w.device = nil
-
-	w.browser, w.version = false, [3]byte{}
-	w.accounts, w.paths = nil, nil
-
-	return nil
-}
-
-// Accounts implements accounts.Wallet, returning the list of accounts pinned to
-// the Ledger hardware wallet. If self-derivation was enabled, the account list
-// is periodically expanded based on current chain state.
-func (w *ledgerWallet) Accounts() []accounts.Account {
-	// Attempt self-derivation if it's running
-	reqc := make(chan struct{}, 1)
-	select {
-	case w.deriveReq <- reqc:
-		// Self-derivation request accepted, wait for it
-		<-reqc
-	default:
-		// Self-derivation offline, throttled or busy, skip
-	}
-	// Return whatever account list we ended up with
-	w.stateLock.RLock()
-	defer w.stateLock.RUnlock()
-
-	cpy := make([]accounts.Account, len(w.accounts))
-	copy(cpy, w.accounts)
-	return cpy
-}
-
-// selfDerive is an account derivation loop that upon request attempts to find
-// new non-zero accounts.
-func (w *ledgerWallet) selfDerive() {
-	w.log.Debug("Ledger self-derivation started")
-	defer w.log.Debug("Ledger self-derivation stopped")
-
-	// Execute self-derivations until termination or error
-	var (
-		reqc chan struct{}
-		errc chan error
-		err  error
-	)
-	for errc == nil && err == nil {
-		// Wait until either derivation or termination is requested
-		select {
-		case errc = <-w.deriveQuit:
-			// Termination requested
-			continue
-		case reqc = <-w.deriveReq:
-			// Account discovery requested
-		}
-		// Derivation needs a chain and device access, skip if either unavailable
-		w.stateLock.RLock()
-		if w.device == nil || w.deriveChain == nil || w.offline() {
-			w.stateLock.RUnlock()
-			reqc <- struct{}{}
-			continue
-		}
-		select {
-		case <-w.commsLock:
-		default:
-			w.stateLock.RUnlock()
-			reqc <- struct{}{}
-			continue
-		}
-		// Device lock obtained, derive the next batch of accounts
-		var (
-			accs  []accounts.Account
-			paths []accounts.DerivationPath
-
-			nextAddr = w.deriveNextAddr
-			nextPath = w.deriveNextPath
-
-			context = context.Background()
-		)
-		for empty := false; !empty; {
-			// Retrieve the next derived Ethereum account
-			if nextAddr == (common.Address{}) {
-				if nextAddr, err = w.ledgerDerive(nextPath); err != nil {
-					w.log.Warn("Ledger account derivation failed", "err", err)
-					break
-				}
-			}
-			// Check the account's status against the current chain state
-			var (
-				balance *big.Int
-				nonce   uint64
-			)
-			balance, err = w.deriveChain.BalanceAt(context, nextAddr, nil)
-			if err != nil {
-				w.log.Warn("Ledger balance retrieval failed", "err", err)
-				break
-			}
-			nonce, err = w.deriveChain.NonceAt(context, nextAddr, nil)
-			if err != nil {
-				w.log.Warn("Ledger nonce retrieval failed", "err", err)
-				break
-			}
-			// If the next account is empty, stop self-derivation, but add it nonetheless
-			if balance.Sign() == 0 && nonce == 0 {
-				empty = true
-			}
-			// We've just self-derived a new account, start tracking it locally
-			path := make(accounts.DerivationPath, len(nextPath))
-			copy(path[:], nextPath[:])
-			paths = append(paths, path)
-
-			account := accounts.Account{
-				Address: nextAddr,
-				URL:     accounts.URL{Scheme: w.url.Scheme, Path: fmt.Sprintf("%s/%s", w.url.Path, path)},
-			}
-			accs = append(accs, account)
-
-			// Display a log message to the user for new (or previously empty accounts)
-			if _, known := w.paths[nextAddr]; !known || (!empty && nextAddr == w.deriveNextAddr) {
-				w.log.Info("Ledger discovered new account", "address", nextAddr, "path", path, "balance", balance, "nonce", nonce)
-			}
-			// Fetch the next potential account
-			if !empty {
-				nextAddr = common.Address{}
-				nextPath[len(nextPath)-1]++
-			}
-		}
-		// Self derivation complete, release device lock
-		w.commsLock <- struct{}{}
-		w.stateLock.RUnlock()
-
-		// Insert any accounts successfully derived
-		w.stateLock.Lock()
-		for i := 0; i < len(accs); i++ {
-			if _, ok := w.paths[accs[i].Address]; !ok {
-				w.accounts = append(w.accounts, accs[i])
-				w.paths[accs[i].Address] = paths[i]
-			}
-		}
-		// Shift the self-derivation forward
-		// TODO(karalabe): don't overwrite changes from wallet.SelfDerive
-		w.deriveNextAddr = nextAddr
-		w.deriveNextPath = nextPath
-		w.stateLock.Unlock()
-
-		// Notify the user of termination and loop after a bit of time (to avoid trashing)
-		reqc <- struct{}{}
-		if err == nil {
-			select {
-			case errc = <-w.deriveQuit:
-				// Termination requested, abort
-			case <-time.After(selfDeriveThrottling):
-				// Waited enough, willing to self-derive again
-			}
-		}
-	}
-	// In case of error, wait for termination
-	if err != nil {
-		w.log.Debug("Ledger self-derivation failed", "err", err)
-		errc = <-w.deriveQuit
-	}
-	errc <- err
-}
-
-// Contains implements accounts.Wallet, returning whether a particular account is
-// or is not pinned into this Ledger instance. Although we could attempt to resolve
-// unpinned accounts, that would be an non-negligible hardware operation.
-func (w *ledgerWallet) Contains(account accounts.Account) bool {
-	w.stateLock.RLock()
-	defer w.stateLock.RUnlock()
-
-	_, exists := w.paths[account.Address]
-	return exists
-}
-
-// Derive implements accounts.Wallet, deriving a new account at the specific
-// derivation path. If pin is set to true, the account will be added to the list
-// of tracked accounts.
-func (w *ledgerWallet) Derive(path accounts.DerivationPath, pin bool) (accounts.Account, error) {
-	// Try to derive the actual account and update its URL if successful
-	w.stateLock.RLock() // Avoid device disappearing during derivation
-
-	if w.device == nil || w.offline() {
-		w.stateLock.RUnlock()
-		return accounts.Account{}, accounts.ErrWalletClosed
-	}
-	<-w.commsLock // Avoid concurrent hardware access
-	address, err := w.ledgerDerive(path)
-	w.commsLock <- struct{}{}
-
-	w.stateLock.RUnlock()
-
-	// If an error occurred or no pinning was requested, return
-	if err != nil {
-		return accounts.Account{}, err
-	}
-	account := accounts.Account{
-		Address: address,
-		URL:     accounts.URL{Scheme: w.url.Scheme, Path: fmt.Sprintf("%s/%s", w.url.Path, path)},
-	}
-	if !pin {
-		return account, nil
-	}
-	// Pinning needs to modify the state
-	w.stateLock.Lock()
-	defer w.stateLock.Unlock()
-
-	if _, ok := w.paths[address]; !ok {
-		w.accounts = append(w.accounts, account)
-		w.paths[address] = path
-	}
-	return account, nil
-}
-
-// SelfDerive implements accounts.Wallet, trying to discover accounts that the
-// user used previously (based on the chain state), but ones that he/she did not
-// explicitly pin to the wallet manually. To avoid chain head monitoring, self
-// derivation only runs during account listing (and even then throttled).
-func (w *ledgerWallet) SelfDerive(base accounts.DerivationPath, chain ethereum.ChainStateReader) {
-	w.stateLock.Lock()
-	defer w.stateLock.Unlock()
-
-	w.deriveNextPath = make(accounts.DerivationPath, len(base))
-	copy(w.deriveNextPath[:], base[:])
-
-	w.deriveNextAddr = common.Address{}
-	w.deriveChain = chain
-}
-
-// SignHash implements accounts.Wallet, however signing arbitrary data is not
-// supported for Ledger wallets, so this method will always return an error.
-func (w *ledgerWallet) SignHash(acc accounts.Account, hash []byte) ([]byte, error) {
-	return nil, accounts.ErrNotSupported
-}
-
-// SignTx implements accounts.Wallet. It sends the transaction over to the Ledger
-// wallet to request a confirmation from the user. It returns either the signed
-// transaction or a failure if the user denied the transaction.
-//
-// Note, if the version of the Ethereum application running on the Ledger wallet is
-// too old to sign EIP-155 transactions, but such is requested nonetheless, an error
-// will be returned opposed to silently signing in Homestead mode.
-func (w *ledgerWallet) SignTx(account accounts.Account, tx *types.Transaction, chainID *big.Int) (*types.Transaction, error) {
-	w.stateLock.RLock() // Comms have own mutex, this is for the state fields
-	defer w.stateLock.RUnlock()
-
-	// If the wallet is closed, or the Ethereum app doesn't run, abort
-	if w.device == nil || w.offline() {
-		return nil, accounts.ErrWalletClosed
-	}
-	// Make sure the requested account is contained within
-	path, ok := w.paths[account.Address]
-	if !ok {
-		return nil, accounts.ErrUnknownAccount
-	}
-	// Ensure the wallet is capable of signing the given transaction
-	if chainID != nil && w.version[0] <= 1 && w.version[1] <= 0 && w.version[2] <= 2 {
-		return nil, fmt.Errorf("Ledger v%d.%d.%d doesn't support signing this transaction, please update to v1.0.3 at least", w.version[0], w.version[1], w.version[2])
-	}
-	// All infos gathered and metadata checks out, request signing
-	<-w.commsLock
-	defer func() { w.commsLock <- struct{}{} }()
-
-	// Ensure the device isn't screwed with while user confirmation is pending
-	// TODO(karalabe): remove if hotplug lands on Windows
-	w.hub.commsLock.Lock()
-	w.hub.commsPend++
-	w.hub.commsLock.Unlock()
-
-	defer func() {
-		w.hub.commsLock.Lock()
-		w.hub.commsPend--
-		w.hub.commsLock.Unlock()
-	}()
-	return w.ledgerSign(path, account.Address, tx, chainID)
-}
-
-// SignHashWithPassphrase implements accounts.Wallet, however signing arbitrary
-// data is not supported for Ledger wallets, so this method will always return
-// an error.
-func (w *ledgerWallet) SignHashWithPassphrase(account accounts.Account, passphrase string, hash []byte) ([]byte, error) {
-	return nil, accounts.ErrNotSupported
-}
-
-// SignTxWithPassphrase implements accounts.Wallet, attempting to sign the given
-// transaction with the given account using passphrase as extra authentication.
-// Since the Ledger does not support extra passphrases, it is silently ignored.
-func (w *ledgerWallet) SignTxWithPassphrase(account accounts.Account, passphrase string, tx *types.Transaction, chainID *big.Int) (*types.Transaction, error) {
-	return w.SignTx(account, tx, chainID)
-}
-
-// ledgerVersion retrieves the current version of the Ethereum wallet app running
-// on the Ledger wallet.
-//
-// The version retrieval protocol is defined as follows:
-//
-//   CLA | INS | P1 | P2 | Lc | Le
-//   ----+-----+----+----+----+---
-//    E0 | 06  | 00 | 00 | 00 | 04
-//
-// With no input data, and the output data being:
-//
-//   Description                                        | Length
-//   ---------------------------------------------------+--------
-//   Flags 01: arbitrary data signature enabled by user | 1 byte
-//   Application major version                          | 1 byte
-//   Application minor version                          | 1 byte
-//   Application patch version                          | 1 byte
-func (w *ledgerWallet) ledgerVersion() ([3]byte, error) {
-	// Send the request and wait for the response
-	reply, err := w.ledgerExchange(ledgerOpGetConfiguration, 0, 0, nil)
-	if err != nil {
-		return [3]byte{}, err
-	}
-	if len(reply) != 4 {
-		return [3]byte{}, errInvalidVersionReply
-	}
-	// Cache the version for future reference
-	var version [3]byte
-	copy(version[:], reply[1:])
-	return version, nil
-}
-
-// ledgerDerive retrieves the currently active Ethereum address from a Ledger
-// wallet at the specified derivation path.
-//
-// The address derivation protocol is defined as follows:
-//
-//   CLA | INS | P1 | P2 | Lc  | Le
-//   ----+-----+----+----+-----+---
-//    E0 | 02  | 00 return address
-//               01 display address and confirm before returning
-//                  | 00: do not return the chain code
-//                  | 01: return the chain code
-//                       | var | 00
-//
-// Where the input data is:
-//
-//   Description                                      | Length
-//   -------------------------------------------------+--------
-//   Number of BIP 32 derivations to perform (max 10) | 1 byte
-//   First derivation index (big endian)              | 4 bytes
-//   ...                                              | 4 bytes
-//   Last derivation index (big endian)               | 4 bytes
-//
-// And the output data is:
-//
-//   Description             | Length
-//   ------------------------+-------------------
-//   Public Key length       | 1 byte
-//   Uncompressed Public Key | arbitrary
-//   Ethereum address length | 1 byte
-//   Ethereum address        | 40 bytes hex ascii
-//   Chain code if requested | 32 bytes
-func (w *ledgerWallet) ledgerDerive(derivationPath []uint32) (common.Address, error) {
-	// Flatten the derivation path into the Ledger request
-	path := make([]byte, 1+4*len(derivationPath))
-	path[0] = byte(len(derivationPath))
-	for i, component := range derivationPath {
-		binary.BigEndian.PutUint32(path[1+4*i:], component)
-	}
-	// Send the request and wait for the response
-	reply, err := w.ledgerExchange(ledgerOpRetrieveAddress, ledgerP1DirectlyFetchAddress, ledgerP2DiscardAddressChainCode, path)
-	if err != nil {
-		return common.Address{}, err
-	}
-	// Discard the public key, we don't need that for now
-	if len(reply) < 1 || len(reply) < 1+int(reply[0]) {
-		return common.Address{}, errors.New("reply lacks public key entry")
-	}
-	reply = reply[1+int(reply[0]):]
-
-	// Extract the Ethereum hex address string
-	if len(reply) < 1 || len(reply) < 1+int(reply[0]) {
-		return common.Address{}, errors.New("reply lacks address entry")
-	}
-	hexstr := reply[1 : 1+int(reply[0])]
-
-	// Decode the hex sting into an Ethereum address and return
-	var address common.Address
-	hex.Decode(address[:], hexstr)
-	return address, nil
-}
-
-// ledgerSign sends the transaction to the Ledger wallet, and waits for the user
-// to confirm or deny the transaction.
-//
-// The transaction signing protocol is defined as follows:
-//
-//   CLA | INS | P1 | P2 | Lc  | Le
-//   ----+-----+----+----+-----+---
-//    E0 | 04  | 00: first transaction data block
-//               80: subsequent transaction data block
-//                  | 00 | variable | variable
-//
-// Where the input for the first transaction block (first 255 bytes) is:
-//
-//   Description                                      | Length
-//   -------------------------------------------------+----------
-//   Number of BIP 32 derivations to perform (max 10) | 1 byte
-//   First derivation index (big endian)              | 4 bytes
-//   ...                                              | 4 bytes
-//   Last derivation index (big endian)               | 4 bytes
-//   RLP transaction chunk                            | arbitrary
-//
-// And the input for subsequent transaction blocks (first 255 bytes) are:
-//
-//   Description           | Length
-//   ----------------------+----------
-//   RLP transaction chunk | arbitrary
-//
-// And the output data is:
-//
-//   Description | Length
-//   ------------+---------
-//   signature V | 1 byte
-//   signature R | 32 bytes
-//   signature S | 32 bytes
-func (w *ledgerWallet) ledgerSign(derivationPath []uint32, address common.Address, tx *types.Transaction, chainID *big.Int) (*types.Transaction, error) {
-	// Flatten the derivation path into the Ledger request
-	path := make([]byte, 1+4*len(derivationPath))
-	path[0] = byte(len(derivationPath))
-	for i, component := range derivationPath {
-		binary.BigEndian.PutUint32(path[1+4*i:], component)
-	}
-	// Create the transaction RLP based on whether legacy or EIP155 signing was requeste
-	var (
-		txrlp []byte
-		err   error
-	)
-	if chainID == nil {
-		if txrlp, err = rlp.EncodeToBytes([]interface{}{tx.Nonce(), tx.GasPrice(), tx.Gas(), tx.To(), tx.Value(), tx.Data()}); err != nil {
-			return nil, err
-		}
-	} else {
-		if txrlp, err = rlp.EncodeToBytes([]interface{}{tx.Nonce(), tx.GasPrice(), tx.Gas(), tx.To(), tx.Value(), tx.Data(), chainID, big.NewInt(0), big.NewInt(0)}); err != nil {
-			return nil, err
-		}
-	}
-	payload := append(path, txrlp...)
-
-	// Send the request and wait for the response
-	var (
-		op    = ledgerP1InitTransactionData
-		reply []byte
-	)
-	for len(payload) > 0 {
-		// Calculate the size of the next data chunk
-		chunk := 255
-		if chunk > len(payload) {
-			chunk = len(payload)
-		}
-		// Send the chunk over, ensuring it's processed correctly
-		reply, err = w.ledgerExchange(ledgerOpSignTransaction, op, 0, payload[:chunk])
-		if err != nil {
-			return nil, err
-		}
-		// Shift the payload and ensure subsequent chunks are marked as such
-		payload = payload[chunk:]
-		op = ledgerP1ContTransactionData
-	}
-	// Extract the Ethereum signature and do a sanity validation
-	if len(reply) != 65 {
-		return nil, errors.New("reply lacks signature")
-	}
-	signature := append(reply[1:], reply[0])
-
-	// Create the correct signer and signature transform based on the chain ID
-	var signer types.Signer
-	if chainID == nil {
-		signer = new(types.HomesteadSigner)
-	} else {
-		signer = types.NewEIP155Signer(chainID)
-		signature[64] = signature[64] - byte(chainID.Uint64()*2+35)
-	}
-	// Inject the final signature into the transaction and sanity check the sender
-	signed, err := tx.WithSignature(signer, signature)
-	if err != nil {
-		return nil, err
-	}
-	sender, err := types.Sender(signer, signed)
-	if err != nil {
-		return nil, err
-	}
-	if sender != address {
-		return nil, fmt.Errorf("signer mismatch: expected %s, got %s", address.Hex(), sender.Hex())
-	}
-	return signed, nil
-}
-
-// ledgerExchange performs a data exchange with the Ledger wallet, sending it a
-// message and retrieving the response.
-//
-// The common transport header is defined as follows:
-//
-//  Description                           | Length
-//  --------------------------------------+----------
-//  Communication channel ID (big endian) | 2 bytes
-//  Command tag                           | 1 byte
-//  Packet sequence index (big endian)    | 2 bytes
-//  Payload                               | arbitrary
-//
-// The Communication channel ID allows commands multiplexing over the same
-// physical link. It is not used for the time being, and should be set to 0101
-// to avoid compatibility issues with implementations ignoring a leading 00 byte.
-//
-// The Command tag describes the message content. Use TAG_APDU (0x05) for standard
-// APDU payloads, or TAG_PING (0x02) for a simple link test.
-//
-// The Packet sequence index describes the current sequence for fragmented payloads.
-// The first fragment index is 0x00.
-//
-// APDU Command payloads are encoded as follows:
-//
-//  Description              | Length
-//  -----------------------------------
-//  APDU length (big endian) | 2 bytes
-//  APDU CLA                 | 1 byte
-//  APDU INS                 | 1 byte
-//  APDU P1                  | 1 byte
-//  APDU P2                  | 1 byte
-//  APDU length              | 1 byte
-//  Optional APDU data       | arbitrary
-func (w *ledgerWallet) ledgerExchange(opcode ledgerOpcode, p1 ledgerParam1, p2 ledgerParam2, data []byte) ([]byte, error) {
-	// Construct the message payload, possibly split into multiple chunks
-	apdu := make([]byte, 2, 7+len(data))
-
-	binary.BigEndian.PutUint16(apdu, uint16(5+len(data)))
-	apdu = append(apdu, []byte{0xe0, byte(opcode), byte(p1), byte(p2), byte(len(data))}...)
-	apdu = append(apdu, data...)
-
-	// Stream all the chunks to the device
-	header := []byte{0x01, 0x01, 0x05, 0x00, 0x00} // Channel ID and command tag appended
-	chunk := make([]byte, 64)
-	space := len(chunk) - len(header)
-
-	for i := 0; len(apdu) > 0; i++ {
-		// Construct the new message to stream
-		chunk = append(chunk[:0], header...)
-		binary.BigEndian.PutUint16(chunk[3:], uint16(i))
-
-		if len(apdu) > space {
-			chunk = append(chunk, apdu[:space]...)
-			apdu = apdu[space:]
-		} else {
-			chunk = append(chunk, apdu...)
-			apdu = nil
-		}
-		// Send over to the device
-		w.log.Trace("Data chunk sent to the Ledger", "chunk", hexutil.Bytes(chunk))
-		if _, err := w.device.Write(chunk); err != nil {
-			return nil, err
-		}
-	}
-	// Stream the reply back from the wallet in 64 byte chunks
-	var reply []byte
-	chunk = chunk[:64] // Yeah, we surely have enough space
-	for {
-		// Read the next chunk from the Ledger wallet
-		if _, err := io.ReadFull(w.device, chunk); err != nil {
-			return nil, err
-		}
-		w.log.Trace("Data chunk received from the Ledger", "chunk", hexutil.Bytes(chunk))
-
-		// Make sure the transport header matches
-		if chunk[0] != 0x01 || chunk[1] != 0x01 || chunk[2] != 0x05 {
-			return nil, errReplyInvalidHeader
-		}
-		// If it's the first chunk, retrieve the total message length
-		var payload []byte
-
-		if chunk[3] == 0x00 && chunk[4] == 0x00 {
-			reply = make([]byte, 0, int(binary.BigEndian.Uint16(chunk[5:7])))
-			payload = chunk[7:]
-		} else {
-			payload = chunk[5:]
-		}
-		// Append to the reply and stop when filled up
-		if left := cap(reply) - len(reply); left > len(payload) {
-			reply = append(reply, payload...)
-		} else {
-			reply = append(reply, payload[:left]...)
-			break
-		}
-	}
-	return reply[:len(reply)-2], nil
-}