// 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/>.
package adapters
import (
"crypto/ecdsa"
"encoding/hex"
"encoding/json"
"fmt"
"net"
"os"
"strconv"
"github.com/docker/docker/pkg/reexec"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/node"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/p2p/enode"
"github.com/ethereum/go-ethereum/rpc"
)
// Node represents a node in a simulation network which is created by a
// NodeAdapter, for example:
//
// * SimNode - An in-memory node
// * ExecNode - A child process node
// * DockerNode - A Docker container node
//
type Node interface {
// Addr returns the node's address (e.g. an Enode URL)
Addr() []byte
// Client returns the RPC client which is created once the node is
// up and running
Client() (*rpc.Client, error)
// ServeRPC serves RPC requests over the given connection
ServeRPC(net.Conn) error
// Start starts the node with the given snapshots
Start(snapshots map[string][]byte) error
// Stop stops the node
Stop() error
// NodeInfo returns information about the node
NodeInfo() *p2p.NodeInfo
// Snapshots creates snapshots of the running services
Snapshots() (map[string][]byte, error)
}
// NodeAdapter is used to create Nodes in a simulation network
type NodeAdapter interface {
// Name returns the name of the adapter for logging purposes
Name() string
// NewNode creates a new node with the given configuration
NewNode(config *NodeConfig) (Node, error)
}
// NodeConfig is the configuration used to start a node in a simulation
// network
type NodeConfig struct {
// ID is the node's ID which is used to identify the node in the
// simulation network
ID enode.ID
// PrivateKey is the node's private key which is used by the devp2p
// stack to encrypt communications
PrivateKey *ecdsa.PrivateKey
// Enable peer events for Msgs
EnableMsgEvents bool
// Name is a human friendly name for the node like "node01"
Name string
// Services are the names of the services which should be run when
// starting the node (for SimNodes it should be the names of services
// contained in SimAdapter.services, for other nodes it should be
// services registered by calling the RegisterService function)
Services []string
// function to sanction or prevent suggesting a peer
Reachable func(id enode.ID) bool
Port uint16
}
// nodeConfigJSON is used to encode and decode NodeConfig as JSON by encoding
// all fields as strings
type nodeConfigJSON struct {
ID string `json:"id"`
PrivateKey string `json:"private_key"`
Name string `json:"name"`
Services []string `json:"services"`
EnableMsgEvents bool `json:"enable_msg_events"`
Port uint16 `json:"port"`
}
// MarshalJSON implements the json.Marshaler interface by encoding the config
// fields as strings
func (n *NodeConfig) MarshalJSON() ([]byte, error) {
confJSON := nodeConfigJSON{
ID: n.ID.String(),
Name: n.Name,
Services: n.Services,
Port: n.Port,
EnableMsgEvents: n.EnableMsgEvents,
}
if n.PrivateKey != nil {
confJSON.PrivateKey = hex.EncodeToString(crypto.FromECDSA(n.PrivateKey))
}
return json.Marshal(confJSON)
}
// UnmarshalJSON implements the json.Unmarshaler interface by decoding the json
// string values into the config fields
func (n *NodeConfig) UnmarshalJSON(data []byte) error {
var confJSON nodeConfigJSON
if err := json.Unmarshal(data, &confJSON); err != nil {
return err
}
if confJSON.ID != "" {
if err := n.ID.UnmarshalText([]byte(confJSON.ID)); err != nil {
return err
}
}
if confJSON.PrivateKey != "" {
key, err := hex.DecodeString(confJSON.PrivateKey)
if err != nil {
return err
}
privKey, err := crypto.ToECDSA(key)
if err != nil {
return err
}
n.PrivateKey = privKey
}
n.Name = confJSON.Name
n.Services = confJSON.Services
n.Port = confJSON.Port
n.EnableMsgEvents = confJSON.EnableMsgEvents
return nil
}
// Node returns the node descriptor represented by the config.
func (n *NodeConfig) Node() *enode.Node {
return enode.NewV4(&n.PrivateKey.PublicKey, net.IP{127, 0, 0, 1}, int(n.Port), int(n.Port))
}
// RandomNodeConfig returns node configuration with a randomly generated ID and
// PrivateKey
func RandomNodeConfig() *NodeConfig {
key, err := crypto.GenerateKey()
if err != nil {
panic("unable to generate key")
}
id := enode.PubkeyToIDV4(&key.PublicKey)
port, err := assignTCPPort()
if err != nil {
panic("unable to assign tcp port")
}
return &NodeConfig{
ID: id,
Name: fmt.Sprintf("node_%s", id.String()),
PrivateKey: key,
Port: port,
EnableMsgEvents: true,
}
}
func assignTCPPort() (uint16, error) {
l, err := net.Listen("tcp", "127.0.0.1:0")
if err != nil {
return 0, err
}
l.Close()
_, port, err := net.SplitHostPort(l.Addr().String())
if err != nil {
return 0, err
}
p, err := strconv.ParseInt(port, 10, 32)
if err != nil {
return 0, err
}
return uint16(p), nil
}
// ServiceContext is a collection of options and methods which can be utilised
// when starting services
type ServiceContext struct {
RPCDialer
NodeContext *node.ServiceContext
Config *NodeConfig
Snapshot []byte
}
// RPCDialer is used when initialising services which need to connect to
// other nodes in the network (for example a simulated Swarm node which needs
// to connect to a Geth node to resolve ENS names)
type RPCDialer interface {
DialRPC(id enode.ID) (*rpc.Client, error)
}
// Services is a collection of services which can be run in a simulation
type Services map[string]ServiceFunc
// ServiceFunc returns a node.Service which can be used to boot a devp2p node
type ServiceFunc func(ctx *ServiceContext) (node.Service, error)
// serviceFuncs is a map of registered services which are used to boot devp2p
// nodes
var serviceFuncs = make(Services)
// RegisterServices registers the given Services which can then be used to
// start devp2p nodes using either the Exec or Docker adapters.
//
// It should be called in an init function so that it has the opportunity to
// execute the services before main() is called.
func RegisterServices(services Services) {
for name, f := range services {
if _, exists := serviceFuncs[name]; exists {
panic(fmt.Sprintf("node service already exists: %q", name))
}
serviceFuncs[name] = f
}
// now we have registered the services, run reexec.Init() which will
// potentially start one of the services if the current binary has
// been exec'd with argv[0] set to "p2p-node"
if reexec.Init() {
os.Exit(0)
}
}
