path: root/ethereum.go

package eth

import (
    "container/list"
    "fmt"
    "io/ioutil"
    "math/rand"
    "net"
    "net/http"
    "strconv"
    "strings"
    "sync"
    "sync/atomic"
    "time"

    "github.com/ethereum/eth-go/ethchain"
    "github.com/ethereum/eth-go/ethcrypto"
    "github.com/ethereum/eth-go/ethlog"
    "github.com/ethereum/eth-go/ethrpc"
    "github.com/ethereum/eth-go/ethutil"
    "github.com/ethereum/eth-go/ethwire"
)

const seedTextFileUri string = "http://www.ethereum.org/servers.poc3.txt"

var ethlogger = ethlog.NewLogger("SERV")

func eachPeer(peers *list.List, callback func(*Peer, *list.Element)) {
    // Loop thru the peers and close them (if we had them)
    for e := peers.Front(); e != nil; e = e.Next() {
        if peer, ok := e.Value.(*Peer); ok {
            callback(peer, e)
        }
    }
}

const (
    processReapingTimeout = 60 // TODO increase
)

type Ethereum struct {
    // Channel for shutting down the ethereum
    shutdownChan chan bool
    quit         chan bool
    // DB interface
    //db *ethdb.LDBDatabase
    db ethutil.Database
    // State manager for processing new blocks and managing the over all states
    stateManager *ethchain.StateManager
    // The transaction pool. Transaction can be pushed on this pool
    // for later including in the blocks
    txPool *ethchain.TxPool
    // The canonical chain
    blockChain *ethchain.BlockChain
    // Peers (NYI)
    peers *list.List
    // Nonce
    Nonce uint64

    Addr net.Addr
    Port string

    peerMut sync.Mutex

    // Capabilities for outgoing peers
    serverCaps Caps

    nat NAT

    // Specifies the desired amount of maximum peers
    MaxPeers int

    Mining bool

    listening bool

    reactor *ethutil.ReactorEngine

    RpcServer *ethrpc.JsonRpcServer

    keyManager *ethcrypto.KeyManager

    clientIdentity ethwire.ClientIdentity

    isUpToDate bool
}

func New(db ethutil.Database, clientIdentity ethwire.ClientIdentity, keyManager *ethcrypto.KeyManager, caps Caps, usePnp bool) (*Ethereum, error) {

    var err error
    var nat NAT

    if usePnp {
        nat, err = Discover()
        if err != nil {
            ethlogger.Debugln("UPnP failed", err)
        }
    }

    ethutil.Config.Db = db

    nonce, _ := ethutil.RandomUint64()
    ethereum := &Ethereum{
        shutdownChan:   make(chan bool),
        quit:           make(chan bool),
        db:             db,
        peers:          list.New(),
        Nonce:          nonce,
        serverCaps:     caps,
        nat:            nat,
        keyManager:     keyManager,
        clientIdentity: clientIdentity,
        isUpToDate:     true,
    }
    ethereum.reactor = ethutil.NewReactorEngine()

    ethereum.txPool = ethchain.NewTxPool(ethereum)
    ethereum.blockChain = ethchain.NewBlockChain(ethereum)
    ethereum.stateManager = ethchain.NewStateManager(ethereum)

    // Start the tx pool
    ethereum.txPool.Start()

    return ethereum, nil
}

func (s *Ethereum) Reactor() *ethutil.ReactorEngine {
    return s.reactor
}

func (s *Ethereum) KeyManager() *ethcrypto.KeyManager {
    return s.keyManager
}

func (s *Ethereum) ClientIdentity() ethwire.ClientIdentity {
    return s.clientIdentity
}

func (s *Ethereum) BlockChain() *ethchain.BlockChain {
    return s.blockChain
}

func (s *Ethereum) StateManager() *ethchain.StateManager {
    return s.stateManager
}

func (s *Ethereum) TxPool() *ethchain.TxPool {
    return s.txPool
}

func (s *Ethereum) ServerCaps() Caps {
    return s.serverCaps
}
func (s *Ethereum) IsMining() bool {
    return s.Mining
}
func (s *Ethereum) PeerCount() int {
    return s.peers.Len()
}
func (s *Ethereum) IsUpToDate() bool {
    upToDate := true
    eachPeer(s.peers, func(peer *Peer, e *list.Element) {
        if atomic.LoadInt32(&peer.connected) == 1 {
            if peer.catchingUp == true && peer.versionKnown {
                upToDate = false
            }
        }
    })
    return upToDate
}
func (s *Ethereum) PushPeer(peer *Peer) {
    s.peers.PushBack(peer)
}
func (s *Ethereum) IsListening() bool {
    return s.listening
}

func (s *Ethereum) AddPeer(conn net.Conn) {
    peer := NewPeer(conn, s, true)

    if peer != nil {
        if s.peers.Len() < s.MaxPeers {
            peer.Start()
        } else {
            ethlogger.Debugf("Max connected peers reached. Not adding incoming peer.")
        }
    }
}

func (s *Ethereum) ProcessPeerList(addrs []string) {
    for _, addr := range addrs {
        // TODO Probably requires some sanity checks
        s.ConnectToPeer(addr)
    }
}

func (s *Ethereum) ConnectToPeer(addr string) error {
    if s.peers.Len() < s.MaxPeers {
        var alreadyConnected bool

        ahost, _, _ := net.SplitHostPort(addr)
        var chost string

        ips, err := net.LookupIP(ahost)

        if err != nil {
            return err
        } else {
            // If more then one ip is available try stripping away the ipv6 ones
            if len(ips) > 1 {
                var ipsv4 []net.IP
                // For now remove the ipv6 addresses
                for _, ip := range ips {
                    if strings.Contains(ip.String(), "::") {
                        continue
                    } else {
                        ipsv4 = append(ipsv4, ip)
                    }
                }
                if len(ipsv4) == 0 {
                    return fmt.Errorf("[SERV] No IPV4 addresses available for hostname")
                }

                // Pick a random ipv4 address, simulating round-robin DNS.
                rand.Seed(time.Now().UTC().UnixNano())
                i := rand.Intn(len(ipsv4))
                chost = ipsv4[i].String()
            } else {
                if len(ips) == 0 {
                    return fmt.Errorf("[SERV] No IPs resolved for the given hostname")
                    return nil
                }
                chost = ips[0].String()
            }
        }

        eachPeer(s.peers, func(p *Peer, v *list.Element) {
            if p.conn == nil {
                return
            }
            phost, _, _ := net.SplitHostPort(p.conn.RemoteAddr().String())

            if phost == chost {
                alreadyConnected = true
                //ethlogger.Debugf("Peer %s already added.\n", chost)
                return
            }
        })

        if alreadyConnected {
            return nil
        }

        NewOutboundPeer(addr, s, s.serverCaps)
    }

    return nil
}

func (s *Ethereum) OutboundPeers() []*Peer {
    // Create a new peer slice with at least the length of the total peers
    outboundPeers := make([]*Peer, s.peers.Len())
    length := 0
    eachPeer(s.peers, func(p *Peer, e *list.Element) {
        if !p.inbound && p.conn != nil {
            outboundPeers[length] = p
            length++
        }
    })

    return outboundPeers[:length]
}

func (s *Ethereum) InboundPeers() []*Peer {
    // Create a new peer slice with at least the length of the total peers
    inboundPeers := make([]*Peer, s.peers.Len())
    length := 0
    eachPeer(s.peers, func(p *Peer, e *list.Element) {
        if p.inbound {
            inboundPeers[length] = p
            length++
        }
    })

    return inboundPeers[:length]
}

func (s *Ethereum) InOutPeers() []*Peer {
    // Reap the dead peers first
    s.reapPeers()

    // Create a new peer slice with at least the length of the total peers
    inboundPeers := make([]*Peer, s.peers.Len())
    length := 0
    eachPeer(s.peers, func(p *Peer, e *list.Element) {
        // Only return peers with an actual ip
        if len(p.host) > 0 {
            inboundPeers[length] = p
            length++
        }
    })

    return inboundPeers[:length]
}

func (s *Ethereum) Broadcast(msgType ethwire.MsgType, data []interface{}) {
    msg := ethwire.NewMessage(msgType, data)
    s.BroadcastMsg(msg)
}

func (s *Ethereum) BroadcastMsg(msg *ethwire.Msg) {
    eachPeer(s.peers, func(p *Peer, e *list.Element) {
        p.QueueMessage(msg)
    })
}

func (s *Ethereum) Peers() *list.List {
    return s.peers
}

func (s *Ethereum) reapPeers() {
    eachPeer(s.peers, func(p *Peer, e *list.Element) {
        if atomic.LoadInt32(&p.disconnect) == 1 || (p.inbound && (time.Now().Unix()-p.lastPong) > int64(5*time.Minute)) {
            s.removePeerElement(e)
        }
    })
}

func (s *Ethereum) removePeerElement(e *list.Element) {
    s.peerMut.Lock()
    defer s.peerMut.Unlock()

    s.peers.Remove(e)

    s.reactor.Post("peerList", s.peers)
}

func (s *Ethereum) RemovePeer(p *Peer) {
    eachPeer(s.peers, func(peer *Peer, e *list.Element) {
        if peer == p {
            s.removePeerElement(e)
        }
    })
}

func (s *Ethereum) ReapDeadPeerHandler() {
    reapTimer := time.NewTicker(processReapingTimeout * time.Second)

    for {
        select {
        case <-reapTimer.C:
            s.reapPeers()
        }
    }
}

// Start the ethereum
func (s *Ethereum) Start(seed bool) {
    // Bind to addr and port
    ln, err := net.Listen("tcp", ":"+s.Port)
    if err != nil {
        ethlogger.Warnf("Port %s in use. Connection listening disabled. Acting as client", s.Port)
        s.listening = false
    } else {
        s.listening = true
        // Starting accepting connections
        ethlogger.Infoln("Ready and accepting connections")
        // Start the peer handler
        go s.peerHandler(ln)
    }

    if s.nat != nil {
        go s.upnpUpdateThread()
    }

    // Start the reaping processes
    go s.ReapDeadPeerHandler()
    go s.update()

    if seed {
        s.Seed()
    }
    ethlogger.Infoln("Server started")
}

func (s *Ethereum) Seed() {
    ethlogger.Debugln("Retrieving seed nodes")

    // Eth-Go Bootstrapping
    ips, er := net.LookupIP("seed.bysh.me")
    if er == nil {
        peers := []string{}
        for _, ip := range ips {
            node := fmt.Sprintf("%s:%d", ip.String(), 30303)
            ethlogger.Debugln("Found DNS Go Peer:", node)
            peers = append(peers, node)
        }
        s.ProcessPeerList(peers)
    }

    // Official DNS Bootstrapping
    _, nodes, err := net.LookupSRV("eth", "tcp", "ethereum.org")
    if err == nil {
        peers := []string{}
        // Iterate SRV nodes
        for _, n := range nodes {
            target := n.Target
            port := strconv.Itoa(int(n.Port))
            // Resolve target to ip (Go returns list, so may resolve to multiple ips?)
            addr, err := net.LookupHost(target)
            if err == nil {
                for _, a := range addr {
                    // Build string out of SRV port and Resolved IP
                    peer := net.JoinHostPort(a, port)
                    ethlogger.Debugln("Found DNS Bootstrap Peer:", peer)
                    peers = append(peers, peer)
                }
            } else {
                ethlogger.Debugln("Couldn't resolve :", target)
            }
        }
        // Connect to Peer list
        s.ProcessPeerList(peers)
    } else {
        // Fallback to servers.poc3.txt
        resp, err := http.Get(seedTextFileUri)
        if err != nil {
            ethlogger.Warnln("Fetching seed failed:", err)
            return
        }
        defer resp.Body.Close()
        body, err := ioutil.ReadAll(resp.Body)
        if err != nil {
            ethlogger.Warnln("Reading seed failed:", err)
            return
        }

        s.ConnectToPeer(string(body))
    }
}

func (s *Ethereum) peerHandler(listener net.Listener) {
    for {
        conn, err := listener.Accept()
        if err != nil {
            ethlogger.Debugln(err)

            continue
        }

        go s.AddPeer(conn)
    }
}

func (s *Ethereum) Stop() {
    // Close the database
    defer s.db.Close()

    eachPeer(s.peers, func(p *Peer, e *list.Element) {
        p.Stop()
    })

    close(s.quit)

    if s.RpcServer != nil {
        s.RpcServer.Stop()
    }
    s.txPool.Stop()
    s.stateManager.Stop()

    ethlogger.Infoln("Server stopped")
    close(s.shutdownChan)
}

// This function will wait for a shutdown and resumes main thread execution
func (s *Ethereum) WaitForShutdown() {
    <-s.shutdownChan
}

func (s *Ethereum) upnpUpdateThread() {
    // Go off immediately to prevent code duplication, thereafter we renew
    // lease every 15 minutes.
    timer := time.NewTimer(5 * time.Minute)
    lport, _ := strconv.ParseInt(s.Port, 10, 16)
    first := true
out:
    for {
        select {
        case <-timer.C:
            var err error
            _, err = s.nat.AddPortMapping("TCP", int(lport), int(lport), "eth listen port", 20*60)
            if err != nil {
                ethlogger.Debugln("can't add UPnP port mapping:", err)
                break out
            }
            if first && err == nil {
                _, err = s.nat.GetExternalAddress()
                if err != nil {
                    ethlogger.Debugln("UPnP can't get external address:", err)
                    continue out
                }
                first = false
            }
            timer.Reset(time.Minute * 15)
        case <-s.quit:
            break out
        }
    }

    timer.Stop()

    if err := s.nat.DeletePortMapping("TCP", int(lport), int(lport)); err != nil {
        ethlogger.Debugln("unable to remove UPnP port mapping:", err)
    } else {
        ethlogger.Debugln("succesfully disestablished UPnP port mapping")
    }
}

func (self *Ethereum) update() {
    upToDateTimer := time.NewTicker(1 * time.Second)

out:
    for {
        select {
        case <-upToDateTimer.C:
            if self.IsUpToDate() && !self.isUpToDate {
                self.reactor.Post("chainSync", false)
                self.isUpToDate = true
            } else if !self.IsUpToDate() && self.isUpToDate {
                self.reactor.Post("chainSync", true)
                self.isUpToDate = false
            }
        case <-self.quit:
            break out
        }
    }
}