package eth
import (
"github.com/ethereum/ethchain-go"
"github.com/ethereum/ethutil-go"
"github.com/ethereum/ethwire-go"
"log"
"net"
"strconv"
"strings"
"sync/atomic"
"time"
)
const (
// The size of the output buffer for writing messages
outputBufferSize = 50
)
// Peer capabillities
type Caps byte
const (
CapDiscoveryTy = 0x01
CapTxTy = 0x02
CapChainTy = 0x04
CapDefault = CapChainTy | CapTxTy | CapDiscoveryTy
)
var capsToString = map[Caps]string{
CapDiscoveryTy: "Peer discovery",
CapTxTy: "Transaction relaying",
CapChainTy: "Block chain relaying",
}
func (c Caps) String() string {
var caps []string
if c&CapDiscoveryTy > 0 {
caps = append(caps, capsToString[CapDiscoveryTy])
}
if c&CapChainTy > 0 {
caps = append(caps, capsToString[CapChainTy])
}
if c&CapTxTy > 0 {
caps = append(caps, capsToString[CapTxTy])
}
return strings.Join(caps, " | ")
}
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
host []byte
port uint16
caps Caps
}
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,
port: 30303,
}
}
func NewOutboundPeer(addr string, ethereum *Ethereum, caps Caps) *Peer {
p := &Peer{
outputQueue: make(chan *ethwire.Msg, outputBufferSize),
quit: make(chan bool),
ethereum: ethereum,
inbound: false,
connected: 0,
disconnect: 0,
caps: caps,
}
// Set up the connection in another goroutine so we don't block the main thread
go func() {
conn, err := net.DialTimeout("tcp", addr, 30*time.Second)
if err != nil {
log.Println("Connection to peer failed", err)
p.Stop()
return
}
p.conn = conn
// Atomically set the connection state
atomic.StoreInt32(&p.connected, 1)
atomic.StoreInt32(&p.disconnect, 0)
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
pingTimer := time.NewTicker(2 * time.Minute)
serviceTimer := time.NewTicker(5 * time.Second)
out:
for {
select {
// Main message queue. All outbound messages are processed through here
case msg := <-p.outputQueue:
p.writeMessage(msg)
p.lastSend = time.Now()
// Ping timer sends a ping to the peer each 2 minutes
case <-pingTimer.C:
p.writeMessage(ethwire.NewMessage(ethwire.MsgPingTy, ""))
// Service timer takes care of peer broadcasting, transaction
// posting or block posting
case <-serviceTimer.C:
if p.caps&CapDiscoveryTy > 0 {
msg := p.peersMessage()
p.ethereum.BroadcastMsg(msg)
}
case <-p.quit:
// Break out of the for loop if a quit message is posted
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
msgs, err := ethwire.ReadMessages(p.conn)
for _, msg := range msgs {
if err != nil {
log.Println(err)
break out
}
switch msg.Type {
case ethwire.MsgHandshakeTy:
// Version message
p.handleHandshake(msg)
p.QueueMessage(ethwire.NewMessage(ethwire.MsgGetPeersTy, ""))
case ethwire.MsgDiscTy:
p.Stop()
case ethwire.MsgPingTy:
// Respond back with pong
p.QueueMessage(ethwire.NewMessage(ethwire.MsgPongTy, ""))
case ethwire.MsgPongTy:
// If we received a pong back from a peer we set the
// last pong so the peer handler knows this peer is still
// active.
p.lastPong = time.Now().Unix()
case ethwire.MsgBlockTy:
// Get all blocks and process them
msg.Data = msg.Data
for i := msg.Data.Length() - 1; i >= 0; i-- {
block := ethchain.NewBlockFromRlpValue(msg.Data.Get(i))
err := p.ethereum.BlockManager.ProcessBlock(block)
if err != nil {
log.Println(err)
}
}
case ethwire.MsgTxTy:
// If the message was a transaction queue the transaction
// in the TxPool where it will undergo validation and
// processing when a new block is found
for i := 0; i < msg.Data.Length(); i++ {
p.ethereum.TxPool.QueueTransaction(ethchain.NewTransactionFromRlpValue(msg.Data.Get(i)))
}
case ethwire.MsgGetPeersTy:
// Flag this peer as a 'requested of new peers' this to
// prevent malicious peers being forced.
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 := 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] = unpackAddr(data.Get(i).Get(0), data.Get(i).Get(1).AsUint())
}
// Connect to the list of peers
p.ethereum.ProcessPeerList(peers)
// Mark unrequested again
p.requestedPeerList = false
//}
case ethwire.MsgGetChainTy:
var parent *ethchain.Block
// Length minus one since the very last element in the array is a count
l := msg.Data.Length() - 1
// Ignore empty get chains
if l <= 1 {
break
}
// Amount of parents in the canonical chain
amountOfBlocks := msg.Data.Get(l).AsUint()
// Check each SHA block hash from the message and determine whether
// the SHA is in the database
for i := 0; i < l; i++ {
if data := msg.Data.Get(i).AsBytes(); p.ethereum.BlockManager.BlockChain().HasBlock(data) {
parent = p.ethereum.BlockManager.BlockChain().GetBlock(data)
break
}
}
// If a parent is found send back a reply
if parent != nil {
chain := p.ethereum.BlockManager.BlockChain().GetChainFromHash(parent.Hash(), amountOfBlocks)
p.QueueMessage(ethwire.NewMessage(ethwire.MsgBlockTy, append(chain, amountOfBlocks)))
} else {
// If no blocks are found we send back a reply with msg not in chain
// and the last hash from get chain
lastHash := msg.Data.Get(l - 1)
log.Printf("Sending not in chain with hash %x\n", lastHash.AsRaw())
p.QueueMessage(ethwire.NewMessage(ethwire.MsgNotInChainTy, []interface{}{lastHash.AsRaw()}))
}
case ethwire.MsgNotInChainTy:
log.Printf("Not in chain %x\n", msg.Data)
// TODO
// Unofficial but fun nonetheless
case ethwire.MsgTalkTy:
log.Printf("%v says: %s\n", p.conn.RemoteAddr(), msg.Data.AsString())
}
}
}
p.Stop()
}
func packAddr(address, port string) ([]byte, uint16) {
addr := strings.Split(address, ".")
a, _ := strconv.Atoi(addr[0])
b, _ := strconv.Atoi(addr[1])
c, _ := strconv.Atoi(addr[2])
d, _ := strconv.Atoi(addr[3])
host := []byte{byte(a), byte(b), byte(c), byte(d)}
prt, _ := strconv.Atoi(port)
return host, uint16(prt)
}
func unpackAddr(value *ethutil.RlpValue, p uint64) string {
a := strconv.Itoa(int(value.Get(0).AsUint()))
b := strconv.Itoa(int(value.Get(1).AsUint()))
c := strconv.Itoa(int(value.Get(2).AsUint()))
d := strconv.Itoa(int(value.Get(3).AsUint()))
host := strings.Join([]string{a, b, c, d}, ".")
port := strconv.Itoa(int(p))
return net.JoinHostPort(host, port)
}
func (p *Peer) Start() {
peerHost, peerPort, _ := net.SplitHostPort(p.conn.LocalAddr().String())
servHost, servPort, _ := net.SplitHostPort(p.conn.RemoteAddr().String())
if peerHost == servHost {
log.Println("Connected to self")
p.Stop()
return
}
if p.inbound {
p.host, p.port = packAddr(peerHost, peerPort)
} else {
p.host, p.port = packAddr(servHost, servPort)
}
err := p.pushHandshake()
if err != nil {
log.Printf("Peer can't send outbound version ack", err)
p.Stop()
return
}
// 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, []interface{}{
uint32(0), uint32(0), "/Ethereum(G) v0.0.1/", p.caps, p.port,
})
p.QueueMessage(msg)
return nil
}
func (p *Peer) peersMessage() *ethwire.Msg {
outPeers := make([]interface{}, len(p.ethereum.InOutPeers()))
// Serialise each peer
for i, peer := range p.ethereum.InOutPeers() {
outPeers[i] = peer.RlpData()
}
// Return the message to the peer with the known list of connected clients
return ethwire.NewMessage(ethwire.MsgPeersTy, outPeers)
}
// Pushes the list of outbound peers to the client when requested
func (p *Peer) pushPeers() {
p.QueueMessage(p.peersMessage())
}
func (p *Peer) handleHandshake(msg *ethwire.Msg) {
c := msg.Data
// [PROTOCOL_VERSION, NETWORK_ID, CLIENT_ID]
p.versionKnown = true
var istr string
// If this is an inbound connection send an ack back
if p.inbound {
if port := c.Get(4).AsUint(); port != 0 {
p.port = uint16(port)
}
istr = "inbound"
} else {
msg := ethwire.NewMessage(ethwire.MsgGetChainTy, []interface{}{p.ethereum.BlockManager.BlockChain().CurrentBlock.Hash(), uint64(100)})
p.QueueMessage(msg)
istr = "outbound"
}
if caps := Caps(c.Get(3).AsByte()); caps != 0 {
p.caps = caps
}
log.Printf("peer connect (%s) %v %s [%s]\n", istr, p.conn.RemoteAddr(), c.Get(2).AsString(), p.caps)
}
func (p *Peer) RlpData() []interface{} {
return []interface{}{p.host, p.port /*port*/}
}
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})
}
