package eth
import (
"github.com/ethereum/ethchain-go"
"github.com/ethereum/ethutil-go"
"github.com/ethereum/ethwire-go"
"log"
"net"
"strconv"
"sync/atomic"
"time"
)
const (
// The size of the output buffer for writing messages
outputBufferSize = 50
)
type Peer struct {
// Ethereum interface
ethereum *Ethereum
// Net connection
conn net.Conn
// Output queue which is used to communicate and handle messages
outputQueue chan *ethwire.Msg
// Quit channel
quit chan bool
// Determines whether it's an inbound or outbound peer
inbound bool
// Flag for checking the peer's connectivity state
connected int32
disconnect int32
// Last known message send
lastSend time.Time
// Indicated whether a verack has been send or not
// This flag is used by writeMessage to check if messages are allowed
// to be send or not. If no version is known all messages are ignored.
versionKnown bool
// Last received pong message
lastPong int64
// Indicates whether a MsgGetPeersTy was requested of the peer
// this to prevent receiving false peers.
requestedPeerList bool
}
func NewPeer(conn net.Conn, ethereum *Ethereum, inbound bool) *Peer {
return &Peer{
outputQueue: make(chan *ethwire.Msg, outputBufferSize),
quit: make(chan bool),
ethereum: ethereum,
conn: conn,
inbound: inbound,
disconnect: 0,
connected: 1,
}
}
func NewOutboundPeer(addr string, ethereum *Ethereum) *Peer {
p := &Peer{
outputQueue: make(chan *ethwire.Msg, outputBufferSize),
quit: make(chan bool),
ethereum: ethereum,
inbound: false,
connected: 0,
disconnect: 0,
}
// Set up the connection in another goroutine so we don't block the main thread
go func() {
conn, err := net.Dial("tcp", addr)
if err != nil {
p.Stop()
}
p.conn = conn
// Atomically set the connection state
atomic.StoreInt32(&p.connected, 1)
atomic.StoreInt32(&p.disconnect, 0)
log.Println("Connected to peer ::", conn.RemoteAddr())
p.Start()
}()
return p
}
// Outputs any RLP encoded data to the peer
func (p *Peer) QueueMessage(msg *ethwire.Msg) {
p.outputQueue <- msg
}
func (p *Peer) writeMessage(msg *ethwire.Msg) {
// Ignore the write if we're not connected
if atomic.LoadInt32(&p.connected) != 1 {
return
}
if !p.versionKnown {
switch msg.Type {
case ethwire.MsgHandshakeTy: // Ok
default: // Anything but ack is allowed
return
}
}
err := ethwire.WriteMessage(p.conn, msg)
if err != nil {
log.Println("Can't send message:", err)
// Stop the client if there was an error writing to it
p.Stop()
return
}
}
// Outbound message handler. Outbound messages are handled here
func (p *Peer) HandleOutbound() {
// The ping timer. Makes sure that every 2 minutes a ping is send to the peer
tickleTimer := time.NewTicker(2 * time.Minute)
out:
for {
select {
// Main message queue. All outbound messages are processed through here
case msg := <-p.outputQueue:
p.writeMessage(msg)
p.lastSend = time.Now()
case <-tickleTimer.C:
p.writeMessage(ethwire.NewMessage(ethwire.MsgPingTy, ""))
// Break out of the for loop if a quit message is posted
case <-p.quit:
break out
}
}
clean:
// This loop is for draining the output queue and anybody waiting for us
for {
select {
case <-p.outputQueue:
// TODO
default:
break clean
}
}
}
// Inbound handler. Inbound messages are received here and passed to the appropriate methods
func (p *Peer) HandleInbound() {
out:
for atomic.LoadInt32(&p.disconnect) == 0 {
// Wait for a message from the peer
msg, err := ethwire.ReadMessage(p.conn)
if err != nil {
log.Println(err)
break out
}
if ethutil.Config.Debug {
log.Printf("Received %s\n", msg.Type.String())
}
switch msg.Type {
case ethwire.MsgHandshakeTy:
// Version message
p.handleHandshake(msg)
case ethwire.MsgDiscTy:
p.Stop()
case ethwire.MsgPingTy:
// Respond back with pong
p.QueueMessage(ethwire.NewMessage(ethwire.MsgPongTy, ""))
case ethwire.MsgPongTy:
p.lastPong = time.Now().Unix()
case ethwire.MsgBlockTy:
for i := 0; i < msg.Data.Length(); i++ {
block := ethchain.NewBlockFromRlpValue(msg.Data.Get(i))
err := p.ethereum.BlockManager.ProcessBlock(block)
if err != nil {
log.Println(err)
}
}
case ethwire.MsgTxTy:
for i := 0; i < msg.Data.Length(); i++ {
p.ethereum.TxPool.QueueTransaction(ethchain.NewTransactionFromRlpValue(msg.Data.Get(i)))
}
case ethwire.MsgGetPeersTy:
p.requestedPeerList = true
// Peer asked for list of connected peers
p.pushPeers()
case ethwire.MsgPeersTy:
// Received a list of peers (probably because MsgGetPeersTy was send)
// Only act on message if we actually requested for a peers list
if p.requestedPeerList {
data := ethutil.Conv(msg.Data)
// Create new list of possible peers for the ethereum to process
peers := make([]string, data.Length())
// Parse each possible peer
for i := 0; i < data.Length(); i++ {
peers[i] = data.Get(i).AsString() + strconv.Itoa(int(data.Get(i).AsUint()))
}
// Connect to the list of peers
p.ethereum.ProcessPeerList(peers)
// Mark unrequested again
p.requestedPeerList = false
}
case ethwire.MsgGetChainTy:
}
}
p.Stop()
}
func (p *Peer) Start() {
if !p.inbound {
err := p.pushHandshake()
if err != nil {
log.Printf("Peer can't send outbound version ack", err)
p.Stop()
}
}
// Run the outbound handler in a new goroutine
go p.HandleOutbound()
// Run the inbound handler in a new goroutine
go p.HandleInbound()
}
func (p *Peer) Stop() {
if atomic.AddInt32(&p.disconnect, 1) != 1 {
return
}
close(p.quit)
if atomic.LoadInt32(&p.connected) != 0 {
p.writeMessage(ethwire.NewMessage(ethwire.MsgDiscTy, ""))
p.conn.Close()
}
log.Println("Peer shutdown")
}
func (p *Peer) pushHandshake() error {
msg := ethwire.NewMessage(ethwire.MsgHandshakeTy, ethutil.Encode([]interface{}{
1, 0, p.ethereum.Nonce,
}))
p.QueueMessage(msg)
return nil
}
// Pushes the list of outbound peers to the client when requested
func (p *Peer) pushPeers() {
outPeers := make([]interface{}, len(p.ethereum.OutboundPeers()))
// Serialise each peer
for i, peer := range p.ethereum.OutboundPeers() {
outPeers[i] = peer.RlpEncode()
}
// Send message to the peer with the known list of connected clients
msg := ethwire.NewMessage(ethwire.MsgPeersTy, ethutil.Encode(outPeers))
p.QueueMessage(msg)
}
func (p *Peer) handleHandshake(msg *ethwire.Msg) {
c := msg.Data
// [PROTOCOL_VERSION, NETWORK_ID, CLIENT_ID]
if c.Get(2).AsUint() == p.ethereum.Nonce {
//if msg.Nonce == p.ethereum.Nonce {
log.Println("Peer connected to self, disconnecting")
p.Stop()
return
}
p.versionKnown = true
// If this is an inbound connection send an ack back
if p.inbound {
err := p.pushHandshake()
if err != nil {
log.Println("Peer can't send ack back")
p.Stop()
}
}
}
func (p *Peer) RlpEncode() []byte {
host, prt, err := net.SplitHostPort(p.conn.RemoteAddr().String())
if err != nil {
return nil
}
i, err := strconv.Atoi(prt)
if err != nil {
return nil
}
port := ethutil.NumberToBytes(uint16(i), 16)
return ethutil.Encode([]interface{}{host, port})
}
