142 lines
		
	
	
		
			3.8 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			142 lines
		
	
	
		
			3.8 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
// Copyright 2015 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package useragent
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import (
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	"encoding/json"
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	"fmt"
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	"net"
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	"github.com/ethereum/go-ethereum/accounts"
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	"github.com/ethereum/go-ethereum/common"
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	"github.com/ethereum/go-ethereum/logger"
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	"github.com/ethereum/go-ethereum/logger/glog"
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	"github.com/ethereum/go-ethereum/rpc/shared"
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)
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// remoteFrontend implements xeth.Frontend and will communicate with an external
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// user agent over a connection
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type RemoteFrontend struct {
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	enabled bool
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	mgr     *accounts.Manager
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	d       *json.Decoder
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	e       *json.Encoder
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	n       int
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}
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// NewRemoteFrontend creates a new frontend which will interact with an user agent
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// over the given connection
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func NewRemoteFrontend(conn net.Conn, mgr *accounts.Manager) *RemoteFrontend {
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	return &RemoteFrontend{false, mgr, json.NewDecoder(conn), json.NewEncoder(conn), 0}
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}
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// Enable will enable user interaction
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func (fe *RemoteFrontend) Enable() {
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	fe.enabled = true
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}
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// UnlockAccount asks the user agent for the user password and tries to unlock the account.
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// It will try 3 attempts before giving up.
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func (fe *RemoteFrontend) UnlockAccount(address []byte) bool {
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	if !fe.enabled {
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		return false
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	}
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	err := fe.send(AskPasswordMethod, common.Bytes2Hex(address))
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	if err != nil {
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		glog.V(logger.Error).Infof("Unable to send password request to agent - %v\n", err)
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		return false
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	}
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	passwdRes, err := fe.recv()
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	if err != nil {
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		glog.V(logger.Error).Infof("Unable to recv password response from agent - %v\n", err)
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		return false
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	}
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	if passwd, ok := passwdRes.Result.(string); ok {
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		err = fe.mgr.Unlock(common.BytesToAddress(address), passwd)
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	}
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	if err == nil {
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		return true
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	}
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	glog.V(logger.Debug).Infoln("3 invalid account unlock attempts")
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	return false
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}
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// ConfirmTransaction asks the user for approval
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func (fe *RemoteFrontend) ConfirmTransaction(tx string) bool {
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	if !fe.enabled {
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		return true // backwards compatibility
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	}
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	err := fe.send(ConfirmTransactionMethod, tx)
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	if err != nil {
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		glog.V(logger.Error).Infof("Unable to send tx confirmation request to agent - %v\n", err)
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		return false
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	}
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	confirmResponse, err := fe.recv()
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	if err != nil {
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		glog.V(logger.Error).Infof("Unable to recv tx confirmation response from agent - %v\n", err)
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		return false
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	}
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	if confirmed, ok := confirmResponse.Result.(bool); ok {
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		return confirmed
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	}
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	return false
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}
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// send request to the agent
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func (fe *RemoteFrontend) send(method string, params ...interface{}) error {
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	fe.n += 1
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	p, err := json.Marshal(params)
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	if err != nil {
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		glog.V(logger.Info).Infof("Unable to send agent request %v\n", err)
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		return err
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	}
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	req := shared.Request{
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		Method:  method,
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		Jsonrpc: shared.JsonRpcVersion,
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		Id:      fe.n,
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		Params:  p,
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	}
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	return fe.e.Encode(&req)
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}
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// recv user response from agent
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func (fe *RemoteFrontend) recv() (*shared.SuccessResponse, error) {
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	var res json.RawMessage
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	if err := fe.d.Decode(&res); err != nil {
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		return nil, err
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	}
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	var response shared.SuccessResponse
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	if err := json.Unmarshal(res, &response); err == nil {
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		return &response, nil
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	}
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	return nil, fmt.Errorf("Invalid user agent response")
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}
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