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"
    "encoding/hex"
    "flag"
    "fmt"
    "io/ioutil"
    "log"
    "os"

    "github.com/ethereum/go-ethereum/crypto"
    "github.com/ethereum/go-ethereum/logger"
    "github.com/ethereum/go-ethereum/p2p/discover"
    "github.com/ethereum/go-ethereum/p2p/nat"
)

func main() {
    var (
        listenAddr  = flag.String("addr", ":30301", "listen address")
        genKey      = flag.String("genkey", "", "generate a node key 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>)")

        nodeKey *ecdsa.PrivateKey
        err     error
    )
    flag.Parse()
    logger.AddLogSystem(logger.NewStdLogSystem(os.Stdout, log.LstdFlags, logger.DebugLevel))

    if *genKey != "" {
        writeKey(*genKey)
        os.Exit(0)
    }

    natm, err := nat.Parse(*natdesc)
    if err != nil {
        log.Fatalf("-nat: %v", err)
    }
    switch {
    case *nodeKeyFile == "" && *nodeKeyHex == "":
        log.Fatal("Use -nodekey or -nodekeyhex to specify a private key")
    case *nodeKeyFile != "" && *nodeKeyHex != "":
        log.Fatal("Options -nodekey and -nodekeyhex are mutually exclusive")
    case *nodeKeyFile != "":
        if nodeKey, err = crypto.LoadECDSA(*nodeKeyFile); err != nil {
            log.Fatalf("-nodekey: %v", err)
        }
    case *nodeKeyHex != "":
        if nodeKey, err = crypto.HexToECDSA(*nodeKeyHex); err != nil {
            log.Fatalf("-nodekeyhex: %v", err)
        }
    }

    if _, err := discover.ListenUDP(nodeKey, *listenAddr, natm, ""); err != nil {
        log.Fatal(err)
    }
    select {}
}

func writeKey(target string) {
    key, err := crypto.GenerateKey()
    if err != nil {
        log.Fatal("could not generate key: %v", err)
    }
    b := crypto.FromECDSA(key)
    if target == "-" {
        fmt.Println(hex.EncodeToString(b))
    } else {
        if err := ioutil.WriteFile(target, b, 0600); err != nil {
            log.Fatal("write error: ", err)
        }
    }
}