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.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) 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: // 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 (TODO reverse order?) msg.Data = msg.Data.Get(0) 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 := 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: var parent *ethchain.Block // FIXME msg.Data = msg.Data.Get(0) // Length minus one since the very last element in the array is a count l := msg.Data.Length() - 1 // 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, chain)) } 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) p.QueueMessage(ethwire.NewMessage(ethwire.MsgNotInChainTy, lastHash.AsRaw())) } case ethwire.MsgNotInChainTy: log.Println("Not in chain, not yet implemented") // TODO // Unofficial but fun nonetheless case ethwire.MsgTalkTy: log.Printf("%v says: %s\n", p.conn.RemoteAddr(), msg.Data.Get(0).AsString()) } } 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() } } else { msg := ethwire.NewMessage(ethwire.MsgGetChainTy, []interface{}{p.ethereum.BlockManager.BlockChain().CurrentBlock.Hash(), uint64(100)}) p.QueueMessage(msg) } } 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}) }