path: root/cmd/bootnode/main.go

// Copyright 2015 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// go-ethereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.

// bootnode runs a bootstrap node for the Ethereum Discovery Protocol.
package main

import (
    "crypto/ecdsa"
    "flag"
    "fmt"
    "net"
    "os"

    "github.com/ethereum/go-ethereum/cmd/utils"
    "github.com/ethereum/go-ethereum/crypto"
    "github.com/ethereum/go-ethereum/log"
    "github.com/ethereum/go-ethereum/p2p/discover"
    "github.com/ethereum/go-ethereum/p2p/discv5"
    "github.com/ethereum/go-ethereum/p2p/nat"
    "github.com/ethereum/go-ethereum/p2p/netutil"
)

func main() {
    var (
        listenAddr  = flag.String("addr", ":30301", "listen address")
        genKey      = flag.String("genkey", "", "generate a node key")
        writeAddr   = flag.Bool("writeaddress", false, "write out the node's pubkey hash and quit")
        nodeKeyFile = flag.String("nodekey", "", "private key filename")
        nodeKeyHex  = flag.String("nodekeyhex", "", "private key as hex (for testing)")
        natdesc     = flag.String("nat", "none", "port mapping mechanism (any|none|upnp|pmp|extip:<IP>)")
        netrestrict = flag.String("netrestrict", "", "restrict network communication to the given IP networks (CIDR masks)")
        runv5       = flag.Bool("v5", false, "run a v5 topic discovery bootnode")
        verbosity   = flag.Int("verbosity", int(log.LvlInfo), "log verbosity (0-9)")
        vmodule     = flag.String("vmodule", "", "log verbosity pattern")

        nodeKey *ecdsa.PrivateKey
        err     error
    )
    flag.Parse()

    glogger := log.NewGlogHandler(log.StreamHandler(os.Stderr, log.TerminalFormat(false)))
    glogger.Verbosity(log.Lvl(*verbosity))
    glogger.Vmodule(*vmodule)
    log.Root().SetHandler(glogger)

    natm, err := nat.Parse(*natdesc)
    if err != nil {
        utils.Fatalf("-nat: %v", err)
    }
    switch {
    case *genKey != "":
        nodeKey, err = crypto.GenerateKey()
        if err != nil {
            utils.Fatalf("could not generate key: %v", err)
        }
        if err = crypto.SaveECDSA(*genKey, nodeKey); err != nil {
            utils.Fatalf("%v", err)
        }
        return
    case *nodeKeyFile == "" && *nodeKeyHex == "":
        utils.Fatalf("Use -nodekey or -nodekeyhex to specify a private key")
    case *nodeKeyFile != "" && *nodeKeyHex != "":
        utils.Fatalf("Options -nodekey and -nodekeyhex are mutually exclusive")
    case *nodeKeyFile != "":
        if nodeKey, err = crypto.LoadECDSA(*nodeKeyFile); err != nil {
            utils.Fatalf("-nodekey: %v", err)
        }
    case *nodeKeyHex != "":
        if nodeKey, err = crypto.HexToECDSA(*nodeKeyHex); err != nil {
            utils.Fatalf("-nodekeyhex: %v", err)
        }
    }

    if *writeAddr {
        fmt.Printf("%v\n", discover.PubkeyID(&nodeKey.PublicKey))
        os.Exit(0)
    }

    var restrictList *netutil.Netlist
    if *netrestrict != "" {
        restrictList, err = netutil.ParseNetlist(*netrestrict)
        if err != nil {
            utils.Fatalf("-netrestrict: %v", err)
        }
    }

    addr, err := net.ResolveUDPAddr("udp", *listenAddr)
    if err != nil {
        utils.Fatalf("-ResolveUDPAddr: %v", err)
    }
    conn, err := net.ListenUDP("udp", addr)
    if err != nil {
        utils.Fatalf("-ListenUDP: %v", err)
    }

    realaddr := conn.LocalAddr().(*net.UDPAddr)
    if natm != nil {
        if !realaddr.IP.IsLoopback() {
            go nat.Map(natm, nil, "udp", realaddr.Port, realaddr.Port, "ethereum discovery")
        }
        // TODO: react to external IP changes over time.
        if ext, err := natm.ExternalIP(); err == nil {
            realaddr = &net.UDPAddr{IP: ext, Port: realaddr.Port}
        }
    }

    if *runv5 {
        if _, err := discv5.ListenUDP(nodeKey, conn, realaddr, "", restrictList); err != nil {
            utils.Fatalf("%v", err)
        }
    } else {
        cfg := discover.Config{
            PrivateKey:   nodeKey,
            AnnounceAddr: realaddr,
            NetRestrict:  restrictList,
        }
        if _, err := discover.ListenUDP(conn, cfg); err != nil {
            utils.Fatalf("%v", err)
        }
    }

    select {}
}