path: root/ethereum.go

package eth

import (
    "container/list"
    "github.com/ethereum/eth-go/ethchain"
    "github.com/ethereum/eth-go/ethdb"
    "github.com/ethereum/eth-go/ethutil"
    "github.com/ethereum/eth-go/ethwire"
    "io/ioutil"
    "log"
    "net"
    "net/http"
    "strconv"
    "sync"
    "sync/atomic"
    "time"
)

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
}

func New(caps Caps, usePnp bool) (*Ethereum, error) {
    db, err := ethdb.NewLDBDatabase("database")
    //db, err := ethdb.NewMemDatabase()
    if err != nil {
        return nil, err
    }

    var nat NAT
    if usePnp {
        nat, err = Discover()
        if err != nil {
            ethutil.Config.Log.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,
    }
    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) 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) AddPeer(conn net.Conn) {
    peer := NewPeer(conn, s, true)

    if peer != nil && s.peers.Len() < s.MaxPeers {
        s.peers.PushBack(peer)
        peer.Start()
    }
}

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

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

            if phost == ahost {
                alreadyConnected = true
                return
            }
        })

        if alreadyConnected {
            return nil
        }

        peer := NewOutboundPeer(addr, s, s.serverCaps)

        s.peers.PushBack(peer)

        log.Printf("[SERV] Adding peer %d / %d\n", s.peers.Len(), s.MaxPeers)
    }

    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() {
    s.peerMut.Lock()
    defer s.peerMut.Unlock()

    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.peers.Remove(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() {
    // Bind to addr and port
    ln, err := net.Listen("tcp", ":"+s.Port)
    if err != nil {
        log.Println("Connection listening disabled. Acting as client")
    } else {
        // Starting accepting connections
        ethutil.Config.Log.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()

    if ethutil.Config.Seed {
        ethutil.Config.Log.Debugln("Seeding")
        // 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)
                        log.Println("Found DNS Bootstrap Peer:", peer)
                        peers = append(peers, peer)
                    }
                } else {
                    log.Println("Couldn't resolve :", target)
                }
            }
            // Connect to Peer list
            s.ProcessPeerList(peers)
        } else {
            // Fallback to servers.poc3.txt
            resp, err := http.Get("http://www.ethereum.org/servers.poc3.txt")
            if err != nil {
                log.Println("Fetching seed failed:", err)
                return
            }
            defer resp.Body.Close()
            body, err := ioutil.ReadAll(resp.Body)
            if err != nil {
                log.Println("Reading seed failed:", err)
                return
            }

            s.ConnectToPeer(string(body))
        }
    }
}

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

    s.txPool.Stop()
    s.stateManager.Stop()

    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(0 * time.Second)
    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 {
                ethutil.Config.Log.Debugln("can't add UPnP port mapping:", err)
                break out
            }
            if first && err == nil {
                _, err = s.nat.GetExternalAddress()
                if err != nil {
                    ethutil.Config.Log.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 {
        ethutil.Config.Log.Debugln("unable to remove UPnP port mapping:", err)
    } else {
        ethutil.Config.Log.Debugln("succesfully disestablished UPnP port mapping")
    }
}