// 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 simulations
import (
"bytes"
"context"
"encoding/json"
"fmt"
"sync"
"time"
"github.com/ethereum/go-ethereum/event"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/p2p/enode"
"github.com/ethereum/go-ethereum/p2p/simulations/adapters"
)
var DialBanTimeout = 200 * time.Millisecond
// NetworkConfig defines configuration options for starting a Network
type NetworkConfig struct {
ID string `json:"id"`
DefaultService string `json:"default_service,omitempty"`
}
// Network models a p2p simulation network which consists of a collection of
// simulated nodes and the connections which exist between them.
//
// The Network has a single NodeAdapter which is responsible for actually
// starting nodes and connecting them together.
//
// The Network emits events when nodes are started and stopped, when they are
// connected and disconnected, and also when messages are sent between nodes.
type Network struct {
NetworkConfig
Nodes []*Node `json:"nodes"`
nodeMap map[enode.ID]int
Conns []*Conn `json:"conns"`
connMap map[string]int
nodeAdapter adapters.NodeAdapter
events event.Feed
lock sync.RWMutex
quitc chan struct{}
}
// NewNetwork returns a Network which uses the given NodeAdapter and NetworkConfig
func NewNetwork(nodeAdapter adapters.NodeAdapter, conf *NetworkConfig) *Network {
return &Network{
NetworkConfig: *conf,
nodeAdapter: nodeAdapter,
nodeMap: make(map[enode.ID]int),
connMap: make(map[string]int),
quitc: make(chan struct{}),
}
}
// Events returns the output event feed of the Network.
func (net *Network) Events() *event.Feed {
return &net.events
}
// NewNodeWithConfig adds a new node to the network with the given config,
// returning an error if a node with the same ID or name already exists
func (net *Network) NewNodeWithConfig(conf *adapters.NodeConfig) (*Node, error) {
net.lock.Lock()
defer net.lock.Unlock()
if conf.Reachable == nil {
conf.Reachable = func(otherID enode.ID) bool {
_, err := net.InitConn(conf.ID, otherID)
if err != nil && bytes.Compare(conf.ID.Bytes(), otherID.Bytes()) < 0 {
return false
}
return true
}
}
// check the node doesn't already exist
if node := net.getNode(conf.ID); node != nil {
return nil, fmt.Errorf("node with ID %q already exists", conf.ID)
}
if node := net.getNodeByName(conf.Name); node != nil {
return nil, fmt.Errorf("node with name %q already exists", conf.Name)
}
// if no services are configured, use the default service
if len(conf.Services) == 0 {
conf.Services = []string{net.DefaultService}
}
// use the NodeAdapter to create the node
adapterNode, err := net.nodeAdapter.NewNode(conf)
if err != nil {
return nil, err
}
node := &Node{
Node: adapterNode,
Config: conf,
}
log.Trace(fmt.Sprintf("node %v created", conf.ID))
net.nodeMap[conf.ID] = len(net.Nodes)
net.Nodes = append(net.Nodes, node)
// emit a "control" event
net.events.Send(ControlEvent(node))
return node, nil
}
// Config returns the network configuration
func (net *Network) Config() *NetworkConfig {
return &net.NetworkConfig
}
// StartAll starts all nodes in the network
func (net *Network) StartAll() error {
for _, node := range net.Nodes {
if node.Up {
continue
}
if err := net.Start(node.ID()); err != nil {
return err
}
}
return nil
}
// StopAll stops all nodes in the network
func (net *Network) StopAll() error {
for _, node := range net.Nodes {
if !node.Up {
continue
}
if err := net.Stop(node.ID()); err != nil {
return err
}
}
return nil
}
// Start starts the node with the given ID
func (net *Network) Start(id enode.ID) error {
return net.startWithSnapshots(id, nil)
}
// startWithSnapshots starts the node with the given ID using the give
// snapshots
func (net *Network) startWithSnapshots(id enode.ID, snapshots map[string][]byte) error {
net.lock.Lock()
defer net.lock.Unlock()
node := net.getNode(id)
if node == nil {
return fmt.Errorf("node %v does not exist", id)
}
if node.Up {
return fmt.Errorf("node %v already up", id)
}
log.Trace(fmt.Sprintf("starting node %v: %v using %v", id, node.Up, net.nodeAdapter.Name()))
if err := node.Start(snapshots); err != nil {
log.Warn(fmt.Sprintf("start up failed: %v", err))
return err
}
node.Up = true
log.Info(fmt.Sprintf("started node %v: %v", id, node.Up))
net.events.Send(NewEvent(node))
// subscribe to peer events
client, err := node.Client()
if err != nil {
return fmt.Errorf("error getting rpc client for node %v: %s", id, err)
}
events := make(chan *p2p.PeerEvent)
sub, err := client.Subscribe(context.Background(), "admin", events, "peerEvents")
if err != nil {
return fmt.Errorf("error getting peer events for node %v: %s", id, err)
}
go net.watchPeerEvents(id, events, sub)
return nil
}
// watchPeerEvents reads peer events from the given channel and emits
// corresponding network events
func (net *Network) watchPeerEvents(id enode.ID, events chan *p2p.PeerEvent, sub event.Subscription) {
defer func() {
sub.Unsubscribe()
// assume the node is now down
net.lock.Lock()
defer net.lock.Unlock()
node := net.getNode(id)
if node == nil {
log.Error("Can not find node for id", "id", id)
return
}
node.Up = false
net.events.Send(NewEvent(node))
}()
for {
select {
case event, ok := <-events:
if !ok {
return
}
peer := event.Peer
switch event.Type {
case p2p.PeerEventTypeAdd:
net.DidConnect(id, peer)
case p2p.PeerEventTypeDrop:
net.DidDisconnect(id, peer)
case p2p.PeerEventTypeMsgSend:
net.DidSend(id, peer, event.Protocol, *event.MsgCode)
case p2p.PeerEventTypeMsgRecv:
net.DidReceive(peer, id, event.Protocol, *event.MsgCode)
}
case err := <-sub.Err():
if err != nil {
log.Error(fmt.Sprintf("error getting peer events for node %v", id), "err", err)
}
return
}
}
}
// Stop stops the node with the given ID
func (net *Network) Stop(id enode.ID) error {
net.lock.Lock()
defer net.lock.Unlock()
node := net.getNode(id)
if node == nil {
return fmt.Errorf("node %v does not exist", id)
}
if !node.Up {
return fmt.Errorf("node %v already down", id)
}
if err := node.Stop(); err != nil {
return err
}
node.Up = false
log.Info(fmt.Sprintf("stop node %v: %v", id, node.Up))
net.events.Send(ControlEvent(node))
return nil
}
// Connect connects two nodes together by calling the "admin_addPeer" RPC
// method on the "one" node so that it connects to the "other" node
func (net *Network) Connect(oneID, otherID enode.ID) error {
log.Debug(fmt.Sprintf("connecting %s to %s", oneID, otherID))
conn, err := net.InitConn(oneID, otherID)
if err != nil {
return err
}
client, err := conn.one.Client()
if err != nil {
return err
}
net.events.Send(ControlEvent(conn))
return client.Call(nil, "admin_addPeer", string(conn.other.Addr()))
}
// Disconnect disconnects two nodes by calling the "admin_removePeer" RPC
// method on the "one" node so that it disconnects from the "other" node
func (net *Network) Disconnect(oneID, otherID enode.ID) error {
conn := net.GetConn(oneID, otherID)
if conn == nil {
return fmt.Errorf("connection between %v and %v does not exist", oneID, otherID)
}
if !conn.Up {
return fmt.Errorf("%v and %v already disconnected", oneID, otherID)
}
client, err := conn.one.Client()
if err != nil {
return err
}
net.events.Send(ControlEvent(conn))
return client.Call(nil, "admin_removePeer", string(conn.other.Addr()))
}
// DidConnect tracks the fact that the "one" node connected to the "other" node
func (net *Network) DidConnect(one, other enode.ID) error {
net.lock.Lock()
defer net.lock.Unlock()
conn, err := net.getOrCreateConn(one, other)
if err != nil {
return fmt.Errorf("connection between %v and %v does not exist", one, other)
}
if conn.Up {
return fmt.Errorf("%v and %v already connected", one, other)
}
conn.Up = true
net.events.Send(NewEvent(conn))
return nil
}
// DidDisconnect tracks the fact that the "one" node disconnected from the
// "other" node
func (net *Network) DidDisconnect(one, other enode.ID) error {
net.lock.Lock()
defer net.lock.Unlock()
conn := net.getConn(one, other)
if conn == nil {
return fmt.Errorf("connection between %v and %v does not exist", one, other)
}
if !conn.Up {
return fmt.Errorf("%v and %v already disconnected", one, other)
}
conn.Up = false
conn.initiated = time.Now().Add(-DialBanTimeout)
net.events.Send(NewEvent(conn))
return nil
}
// DidSend tracks the fact that "sender" sent a message to "receiver"
func (net *Network) DidSend(sender, receiver enode.ID, proto string, code uint64) error {
msg := &Msg{
One: sender,
Other: receiver,
Protocol: proto,
Code: code,
Received: false,
}
net.events.Send(NewEvent(msg))
return nil
}
// DidReceive tracks the fact that "receiver" received a message from "sender"
func (net *Network) DidReceive(sender, receiver enode.ID, proto string, code uint64) error {
msg := &Msg{
One: sender,
Other: receiver,
Protocol: proto,
Code: code,
Received: true,
}
net.events.Send(NewEvent(msg))
return nil
}
// GetNode gets the node with the given ID, returning nil if the node does not
// exist
func (net *Network) GetNode(id enode.ID) *Node {
net.lock.Lock()
defer net.lock.Unlock()
return net.getNode(id)
}
// GetNode gets the node with the given name, returning nil if the node does
// not exist
func (net *Network) GetNodeByName(name string) *Node {
net.lock.Lock()
defer net.lock.Unlock()
return net.getNodeByName(name)
}
// GetNodes returns the existing nodes
func (net *Network) GetNodes() (nodes []*Node) {
net.lock.Lock()
defer net.lock.Unlock()
nodes = append(nodes, net.Nodes...)
return nodes
}
func (net *Network) getNode(id enode.ID) *Node {
i, found := net.nodeMap[id]
if !found {
return nil
}
return net.Nodes[i]
}
func (net *Network) getNodeByName(name string) *Node {
for _, node := range net.Nodes {
if node.Config.Name == name {
return node
}
}
return nil
}
// GetConn returns the connection which exists between "one" and "other"
// regardless of which node initiated the connection
func (net *Network) GetConn(oneID, otherID enode.ID) *Conn {
net.lock.Lock()
defer net.lock.Unlock()
return net.getConn(oneID, otherID)
}
// GetOrCreateConn is like GetConn but creates the connection if it doesn't
// already exist
func (net *Network) GetOrCreateConn(oneID, otherID enode.ID) (*Conn, error) {
net.lock.Lock()
defer net.lock.Unlock()
return net.getOrCreateConn(oneID, otherID)
}
func (net *Network) getOrCreateConn(oneID, otherID enode.ID) (*Conn, error) {
if conn := net.getConn(oneID, otherID); conn != nil {
return conn, nil
}
one := net.getNode(oneID)
if one == nil {
return nil, fmt.Errorf("node %v does not exist", oneID)
}
other := net.getNode(otherID)
if other == nil {
return nil, fmt.Errorf("node %v does not exist", otherID)
}
conn := &Conn{
One: oneID,
Other: otherID,
one: one,
other: other,
}
label := ConnLabel(oneID, otherID)
net.connMap[label] = len(net.Conns)
net.Conns = append(net.Conns, conn)
return conn, nil
}
func (net *Network) getConn(oneID, otherID enode.ID) *Conn {
label := ConnLabel(oneID, otherID)
i, found := net.connMap[label]
if !found {
return nil
}
return net.Conns[i]
}
// InitConn(one, other) retrieves the connectiton model for the connection between
// peers one and other, or creates a new one if it does not exist
// the order of nodes does not matter, i.e., Conn(i,j) == Conn(j, i)
// it checks if the connection is already up, and if the nodes are running
// NOTE:
// it also checks whether there has been recent attempt to connect the peers
// this is cheating as the simulation is used as an oracle and know about
// remote peers attempt to connect to a node which will then not initiate the connection
func (net *Network) InitConn(oneID, otherID enode.ID) (*Conn, error) {
net.lock.Lock()
defer net.lock.Unlock()
if oneID == otherID {
return nil, fmt.Errorf("refusing to connect to self %v", oneID)
}
conn, err := net.getOrCreateConn(oneID, otherID)
if err != nil {
return nil, err
}
if conn.Up {
return nil, fmt.Errorf("%v and %v already connected", oneID, otherID)
}
if time.Since(conn.initiated) < DialBanTimeout {
return nil, fmt.Errorf("connection between %v and %v recently attempted", oneID, otherID)
}
err = conn.nodesUp()
if err != nil {
log.Trace(fmt.Sprintf("nodes not up: %v", err))
return nil, fmt.Errorf("nodes not up: %v", err)
}
log.Debug("InitConn - connection initiated")
conn.initiated = time.Now()
return conn, nil
}
// Shutdown stops all nodes in the network and closes the quit channel
func (net *Network) Shutdown() {
for _, node := range net.Nodes {
log.Debug(fmt.Sprintf("stopping node %s", node.ID().TerminalString()))
if err := node.Stop(); err != nil {
log.Warn(fmt.Sprintf("error stopping node %s", node.ID().TerminalString()), "err", err)
}
}
close(net.quitc)
}
//Reset resets all network properties:
//emtpies the nodes and the connection list
func (net *Network) Reset() {
net.lock.Lock()
defer net.lock.Unlock()
//re-initialize the maps
net.connMap = make(map[string]int)
net.nodeMap = make(map[enode.ID]int)
net.Nodes = nil
net.Conns = nil
}
// Node is a wrapper around adapters.Node which is used to track the status
// of a node in the network
type Node struct {
adapters.Node `json:"-"`
// Config if the config used to created the node
Config *adapters.NodeConfig `json:"config"`
// Up tracks whether or not the node is running
Up bool `json:"up"`
}
// ID returns the ID of the node
func (n *Node) ID() enode.ID {
return n.Config.ID
}
// String returns a log-friendly string
func (n *Node) String() string {
return fmt.Sprintf("Node %v", n.ID().TerminalString())
}
// NodeInfo returns information about the node
func (n *Node) NodeInfo() *p2p.NodeInfo {
// avoid a panic if the node is not started yet
if n.Node == nil {
return nil
}
info := n.Node.NodeInfo()
info.Name = n.Config.Name
return info
}
// MarshalJSON implements the json.Marshaler interface so that the encoded
// JSON includes the NodeInfo
func (n *Node) MarshalJSON() ([]byte, error) {
return json.Marshal(struct {
Info *p2p.NodeInfo `json:"info,omitempty"`
Config *adapters.NodeConfig `json:"config,omitempty"`
Up bool `json:"up"`
}{
Info: n.NodeInfo(),
Config: n.Config,
Up: n.Up,
})
}
// Conn represents a connection between two nodes in the network
type Conn struct {
// One is the node which initiated the connection
One enode.ID `json:"one"`
// Other is the node which the connection was made to
Other enode.ID `json:"other"`
// Up tracks whether or not the connection is active
Up bool `json:"up"`
// Registers when the connection was grabbed to dial
initiated time.Time
one *Node
other *Node
}
// nodesUp returns whether both nodes are currently up
func (c *Conn) nodesUp() error {
if !c.one.Up {
return fmt.Errorf("one %v is not up", c.One)
}
if !c.other.Up {
return fmt.Errorf("other %v is not up", c.Other)
}
return nil
}
// String returns a log-friendly string
func (c *Conn) String() string {
return fmt.Sprintf("Conn %v->%v", c.One.TerminalString(), c.Other.TerminalString())
}
// Msg represents a p2p message sent between two nodes in the network
type Msg struct {
One enode.ID `json:"one"`
Other enode.ID `json:"other"`
Protocol string `json:"protocol"`
Code uint64 `json:"code"`
Received bool `json:"received"`
}
// String returns a log-friendly string
func (m *Msg) String() string {
return fmt.Sprintf("Msg(%d) %v->%v", m.Code, m.One.TerminalString(), m.Other.TerminalString())
}
// ConnLabel generates a deterministic string which represents a connection
// between two nodes, used to compare if two connections are between the same
// nodes
func ConnLabel(source, target enode.ID) string {
var first, second enode.ID
if bytes.Compare(source.Bytes(), target.Bytes()) > 0 {
first = target
second = source
} else {
first = source
second = target
}
return fmt.Sprintf("%v-%v", first, second)
}
// Snapshot represents the state of a network at a single point in time and can
// be used to restore the state of a network
type Snapshot struct {
Nodes []NodeSnapshot `json:"nodes,omitempty"`
Conns []Conn `json:"conns,omitempty"`
}
// NodeSnapshot represents the state of a node in the network
type NodeSnapshot struct {
Node Node `json:"node,omitempty"`
// Snapshots is arbitrary data gathered from calling node.Snapshots()
Snapshots map[string][]byte `json:"snapshots,omitempty"`
}
// Snapshot creates a network snapshot
func (net *Network) Snapshot() (*Snapshot, error) {
net.lock.Lock()
defer net.lock.Unlock()
snap := &Snapshot{
Nodes: make([]NodeSnapshot, len(net.Nodes)),
Conns: make([]Conn, len(net.Conns)),
}
for i, node := range net.Nodes {
snap.Nodes[i] = NodeSnapshot{Node: *node}
if !node.Up {
continue
}
snapshots, err := node.Snapshots()
if err != nil {
return nil, err
}
snap.Nodes[i].Snapshots = snapshots
}
for i, conn := range net.Conns {
snap.Conns[i] = *conn
}
return snap, nil
}
// Load loads a network snapshot
func (net *Network) Load(snap *Snapshot) error {
for _, n := range snap.Nodes {
if _, err := net.NewNodeWithConfig(n.Node.Config); err != nil {
return err
}
if !n.Node.Up {
continue
}
if err := net.startWithSnapshots(n.Node.Config.ID, n.Snapshots); err != nil {
return err
}
}
for _, conn := range snap.Conns {
if !net.GetNode(conn.One).Up || !net.GetNode(conn.Other).Up {
//in this case, at least one of the nodes of a connection is not up,
//so it would result in the snapshot `Load` to fail
continue
}
if err := net.Connect(conn.One, conn.Other); err != nil {
return err
}
}
return nil
}
// Subscribe reads control events from a channel and executes them
func (net *Network) Subscribe(events chan *Event) {
for {
select {
case event, ok := <-events:
if !ok {
return
}
if event.Control {
net.executeControlEvent(event)
}
case <-net.quitc:
return
}
}
}
func (net *Network) executeControlEvent(event *Event) {
log.Trace("execute control event", "type", event.Type, "event", event)
switch event.Type {
case EventTypeNode:
if err := net.executeNodeEvent(event); err != nil {
log.Error("error executing node event", "event", event, "err", err)
}
case EventTypeConn:
if err := net.executeConnEvent(event); err != nil {
log.Error("error executing conn event", "event", event, "err", err)
}
case EventTypeMsg:
log.Warn("ignoring control msg event")
}
}
func (net *Network) executeNodeEvent(e *Event) error {
if !e.Node.Up {
return net.Stop(e.Node.ID())
}
if _, err := net.NewNodeWithConfig(e.Node.Config); err != nil {
return err
}
return net.Start(e.Node.ID())
}
func (net *Network) executeConnEvent(e *Event) error {
if e.Conn.Up {
return net.Connect(e.Conn.One, e.Conn.Other)
} else {
return net.Disconnect(e.Conn.One, e.Conn.Other)
}
}
