// 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 node
import (
"crypto/ecdsa"
"encoding/json"
"io/ioutil"
"net"
"os"
"path/filepath"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
"github.com/ethereum/go-ethereum/p2p/discover"
"github.com/ethereum/go-ethereum/p2p/nat"
)
var (
datadirPrivateKey = "nodekey" // Path within the datadir to the node's private key
datadirStaticNodes = "static-nodes.json" // Path within the datadir to the static node list
datadirTrustedNodes = "trusted-nodes.json" // Path within the datadir to the trusted node list
datadirNodeDatabase = "nodes" // Path within the datadir to store the node infos
)
// Config represents a small collection of configuration values to fine tune the
// P2P network layer of a protocol stack. These values can be further extended by
// all registered services.
type Config struct {
// DataDir is the file system folder the node should use for any data storage
// requirements. The configured data directory will not be directly shared with
// registered services, instead those can use utility methods to create/access
// databases or flat files. This enables ephemeral nodes which can fully reside
// in memory.
DataDir string
// This field should be a valid secp256k1 private key that will be used for both
// remote peer identification as well as network traffic encryption. If no key
// is configured, the preset one is loaded from the data dir, generating it if
// needed.
PrivateKey *ecdsa.PrivateKey
// Name sets the node name of this server. Use common.MakeName to create a name
// that follows existing conventions.
Name string
// NoDiscovery specifies whether the peer discovery mechanism should be started
// or not. Disabling is usually useful for protocol debugging (manual topology).
NoDiscovery bool
// Bootstrap nodes used to establish connectivity with the rest of the network.
BootstrapNodes []*discover.Node
// Network interface address on which the node should listen for inbound peers.
ListenAddr string
// If set to a non-nil value, the given NAT port mapper is used to make the
// listening port available to the Internet.
NAT nat.Interface
// If Dialer is set to a non-nil value, the given Dialer is used to dial outbound
// peer connections.
Dialer *net.Dialer
// If NoDial is true, the node will not dial any peers.
NoDial bool
// MaxPeers is the maximum number of peers that can be connected. If this is
// set to zero, then only the configured static and trusted peers can connect.
MaxPeers int
// MaxPendingPeers is the maximum number of peers that can be pending in the
// handshake phase, counted separately for inbound and outbound connections.
// Zero defaults to preset values.
MaxPendingPeers int
}
// NodeKey retrieves the currently configured private key of the node, checking
// first any manually set key, falling back to the one found in the configured
// data folder. If no key can be found, a new one is generated.
func (c *Config) NodeKey() *ecdsa.PrivateKey {
// Use any specifically configured key
if c.PrivateKey != nil {
return c.PrivateKey
}
// Generate ephemeral key if no datadir is being used
if c.DataDir == "" {
key, err := crypto.GenerateKey()
if err != nil {
glog.Fatalf("Failed to generate ephemeral node key: %v", err)
}
return key
}
// Fall back to persistent key from the data directory
keyfile := filepath.Join(c.DataDir, datadirPrivateKey)
if key, err := crypto.LoadECDSA(keyfile); err == nil {
return key
}
// No persistent key found, generate and store a new one
key, err := crypto.GenerateKey()
if err != nil {
glog.Fatalf("Failed to generate node key: %v", err)
}
if err := crypto.SaveECDSA(keyfile, key); err != nil {
glog.V(logger.Error).Infof("Failed to persist node key: %v", err)
}
return key
}
// StaticNodes returns a list of node enode URLs configured as static nodes.
func (c *Config) StaticNodes() []*discover.Node {
return c.parsePersistentNodes(datadirStaticNodes)
}
// TrusterNodes returns a list of node enode URLs configured as trusted nodes.
func (c *Config) TrusterNodes() []*discover.Node {
return c.parsePersistentNodes(datadirTrustedNodes)
}
// parsePersistentNodes parses a list of discovery node URLs loaded from a .json
// file from within the data directory.
func (c *Config) parsePersistentNodes(file string) []*discover.Node {
// Short circuit if no node config is present
if c.DataDir == "" {
return nil
}
path := filepath.Join(c.DataDir, file)
if _, err := os.Stat(path); err != nil {
return nil
}
// Load the nodes from the config file
blob, err := ioutil.ReadFile(path)
if err != nil {
glog.V(logger.Error).Infof("Failed to access nodes: %v", err)
return nil
}
nodelist := []string{}
if err := json.Unmarshal(blob, &nodelist); err != nil {
glog.V(logger.Error).Infof("Failed to load nodes: %v", err)
return nil
}
// Interpret the list as a discovery node array
var nodes []*discover.Node
for _, url := range nodelist {
if url == "" {
continue
}
node, err := discover.ParseNode(url)
if err != nil {
glog.V(logger.Error).Infof("Node URL %s: %v\n", url, err)
continue
}
nodes = append(nodes, node)
}
return nodes
}
