path: root/cmd/wnode/main.go

// Copyright 2017 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/>.

// This is a simple Whisper node. It could be used as a stand-alone bootstrap node.
// Also, could be used for different test and diagnostics purposes.

package main

import (
    "bufio"
    "crypto/ecdsa"
    crand "crypto/rand"
    "crypto/sha512"
    "encoding/binary"
    "encoding/hex"
    "flag"
    "fmt"
    "io/ioutil"
    "os"
    "path/filepath"
    "strconv"
    "strings"
    "time"

    "github.com/ethereum/go-ethereum/cmd/utils"
    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/console"
    "github.com/ethereum/go-ethereum/crypto"
    "github.com/ethereum/go-ethereum/log"
    "github.com/ethereum/go-ethereum/p2p"
    "github.com/ethereum/go-ethereum/p2p/discover"
    "github.com/ethereum/go-ethereum/p2p/nat"
    "github.com/ethereum/go-ethereum/whisper/mailserver"
    whisper "github.com/ethereum/go-ethereum/whisper/whisperv6"
    "golang.org/x/crypto/pbkdf2"
)

const quitCommand = "~Q"
const entropySize = 32

// singletons
var (
    server     *p2p.Server
    shh        *whisper.Whisper
    done       chan struct{}
    mailServer mailserver.WMailServer
    entropy    [entropySize]byte

    input = bufio.NewReader(os.Stdin)
)

// encryption
var (
    symKey  []byte
    pub     *ecdsa.PublicKey
    asymKey *ecdsa.PrivateKey
    nodeid  *ecdsa.PrivateKey
    topic   whisper.TopicType

    asymKeyID    string
    asymFilterID string
    symFilterID  string
    symPass      string
    msPassword   string
)

// cmd arguments
var (
    bootstrapMode  = flag.Bool("standalone", false, "boostrap node: don't initiate connection to peers, just wait for incoming connections")
    forwarderMode  = flag.Bool("forwarder", false, "forwarder mode: only forward messages, neither encrypt nor decrypt messages")
    mailServerMode = flag.Bool("mailserver", false, "mail server mode: delivers expired messages on demand")
    requestMail    = flag.Bool("mailclient", false, "request expired messages from the bootstrap server")
    asymmetricMode = flag.Bool("asym", false, "use asymmetric encryption")
    generateKey    = flag.Bool("generatekey", false, "generate and show the private key")
    fileExMode     = flag.Bool("fileexchange", false, "file exchange mode")
    testMode       = flag.Bool("test", false, "use of predefined parameters for diagnostics (password, etc.)")
    echoMode       = flag.Bool("echo", false, "echo mode: prints some arguments for diagnostics")

    argVerbosity = flag.Int("verbosity", int(log.LvlError), "log verbosity level")
    argTTL       = flag.Uint("ttl", 30, "time-to-live for messages in seconds")
    argWorkTime  = flag.Uint("work", 5, "work time in seconds")
    argMaxSize   = flag.Uint("maxsize", uint(whisper.DefaultMaxMessageSize), "max size of message")
    argPoW       = flag.Float64("pow", whisper.DefaultMinimumPoW, "PoW for normal messages in float format (e.g. 2.7)")
    argServerPoW = flag.Float64("mspow", whisper.DefaultMinimumPoW, "PoW requirement for Mail Server request")

    argIP      = flag.String("ip", "", "IP address and port of this node (e.g. 127.0.0.1:30303)")
    argPub     = flag.String("pub", "", "public key for asymmetric encryption")
    argDBPath  = flag.String("dbpath", "", "path to the server's DB directory")
    argIDFile  = flag.String("idfile", "", "file name with node id (private key)")
    argEnode   = flag.String("boot", "", "bootstrap node you want to connect to (e.g. enode://e454......08d50@52.176.211.200:16428)")
    argTopic   = flag.String("topic", "", "topic in hexadecimal format (e.g. 70a4beef)")
    argSaveDir = flag.String("savedir", "", "directory where all incoming messages will be saved as files")
)

func main() {
    processArgs()
    initialize()
    run()
}

func processArgs() {
    flag.Parse()

    if len(*argIDFile) > 0 {
        var err error
        nodeid, err = crypto.LoadECDSA(*argIDFile)
        if err != nil {
            utils.Fatalf("Failed to load file [%s]: %s.", *argIDFile, err)
        }
    }

    const enodePrefix = "enode://"
    if len(*argEnode) > 0 {
        if (*argEnode)[:len(enodePrefix)] != enodePrefix {
            *argEnode = enodePrefix + *argEnode
        }
    }

    if len(*argTopic) > 0 {
        x, err := hex.DecodeString(*argTopic)
        if err != nil {
            utils.Fatalf("Failed to parse the topic: %s", err)
        }
        topic = whisper.BytesToTopic(x)
    }

    if *asymmetricMode && len(*argPub) > 0 {
        pub = crypto.ToECDSAPub(common.FromHex(*argPub))
        if !isKeyValid(pub) {
            utils.Fatalf("invalid public key")
        }
    }

    if len(*argSaveDir) > 0 {
        if _, err := os.Stat(*argSaveDir); os.IsNotExist(err) {
            utils.Fatalf("Download directory '%s' does not exist", *argSaveDir)
        }
    } else if *fileExMode {
        utils.Fatalf("Parameter 'savedir' is mandatory for file exchange mode")
    }

    if *echoMode {
        echo()
    }
}

func echo() {
    fmt.Printf("ttl = %d \n", *argTTL)
    fmt.Printf("workTime = %d \n", *argWorkTime)
    fmt.Printf("pow = %f \n", *argPoW)
    fmt.Printf("mspow = %f \n", *argServerPoW)
    fmt.Printf("ip = %s \n", *argIP)
    fmt.Printf("pub = %s \n", common.ToHex(crypto.FromECDSAPub(pub)))
    fmt.Printf("idfile = %s \n", *argIDFile)
    fmt.Printf("dbpath = %s \n", *argDBPath)
    fmt.Printf("boot = %s \n", *argEnode)
}

func initialize() {
    log.Root().SetHandler(log.LvlFilterHandler(log.Lvl(*argVerbosity), log.StreamHandler(os.Stderr, log.TerminalFormat(false))))

    done = make(chan struct{})
    var peers []*discover.Node
    var err error

    if *generateKey {
        key, err := crypto.GenerateKey()
        if err != nil {
            utils.Fatalf("Failed to generate private key: %s", err)
        }
        k := hex.EncodeToString(crypto.FromECDSA(key))
        fmt.Printf("Random private key: %s \n", k)
        os.Exit(0)
    }

    if *testMode {
        symPass = "wwww" // ascii code: 0x77777777
        msPassword = "wwww"
    }

    if *bootstrapMode {
        if len(*argIP) == 0 {
            argIP = scanLineA("Please enter your IP and port (e.g. 127.0.0.1:30348): ")
        }
    } else {
        if len(*argEnode) == 0 {
            argEnode = scanLineA("Please enter the peer's enode: ")
        }
        peer := discover.MustParseNode(*argEnode)
        peers = append(peers, peer)
    }

    cfg := &whisper.Config{
        MaxMessageSize:     uint32(*argMaxSize),
        MinimumAcceptedPOW: *argPoW,
    }

    if *mailServerMode {
        if len(msPassword) == 0 {
            msPassword, err = console.Stdin.PromptPassword("Please enter the Mail Server password: ")
            if err != nil {
                utils.Fatalf("Failed to read Mail Server password: %s", err)
            }
        }

        shh = whisper.New(cfg)
        shh.RegisterServer(&mailServer)
        mailServer.Init(shh, *argDBPath, msPassword, *argServerPoW)
    } else {
        shh = whisper.New(cfg)
    }

    if *argPoW != whisper.DefaultMinimumPoW {
        err := shh.SetMinimumPoW(*argPoW)
        if err != nil {
            utils.Fatalf("Failed to set PoW: %s", err)
        }
    }

    if uint32(*argMaxSize) != whisper.DefaultMaxMessageSize {
        err := shh.SetMaxMessageSize(uint32(*argMaxSize))
        if err != nil {
            utils.Fatalf("Failed to set max message size: %s", err)
        }
    }

    asymKeyID, err = shh.NewKeyPair()
    if err != nil {
        utils.Fatalf("Failed to generate a new key pair: %s", err)
    }

    asymKey, err = shh.GetPrivateKey(asymKeyID)
    if err != nil {
        utils.Fatalf("Failed to retrieve a new key pair: %s", err)
    }

    if nodeid == nil {
        tmpID, err := shh.NewKeyPair()
        if err != nil {
            utils.Fatalf("Failed to generate a new key pair: %s", err)
        }

        nodeid, err = shh.GetPrivateKey(tmpID)
        if err != nil {
            utils.Fatalf("Failed to retrieve a new key pair: %s", err)
        }
    }

    maxPeers := 80
    if *bootstrapMode {
        maxPeers = 800
    }

    server = &p2p.Server{
        Config: p2p.Config{
            PrivateKey:     nodeid,
            MaxPeers:       maxPeers,
            Name:           common.MakeName("wnode", "6.0"),
            Protocols:      shh.Protocols(),
            ListenAddr:     *argIP,
            NAT:            nat.Any(),
            BootstrapNodes: peers,
            StaticNodes:    peers,
            TrustedNodes:   peers,
        },
    }

    _, err = crand.Read(entropy[:])
    if err != nil {
        utils.Fatalf("crypto/rand failed: %s", err)
    }
}

func startServer() {
    err := server.Start()
    if err != nil {
        utils.Fatalf("Failed to start Whisper peer: %s.", err)
    }

    fmt.Printf("my public key: %s \n", common.ToHex(crypto.FromECDSAPub(&asymKey.PublicKey)))
    fmt.Println(server.NodeInfo().Enode)

    if *bootstrapMode {
        configureNode()
        fmt.Println("Bootstrap Whisper node started")
    } else {
        fmt.Println("Whisper node started")
        // first see if we can establish connection, then ask for user input
        waitForConnection(true)
        configureNode()
    }

    if !*forwarderMode {
        fmt.Printf("Please type the message. To quit type: '%s'\n", quitCommand)
    }
}

func isKeyValid(k *ecdsa.PublicKey) bool {
    return k.X != nil && k.Y != nil
}

func configureNode() {
    var err error
    var p2pAccept bool

    if *forwarderMode {
        return
    }

    if *asymmetricMode {
        if len(*argPub) == 0 {
            s := scanLine("Please enter the peer's public key: ")
            b := common.FromHex(s)
            if b == nil {
                utils.Fatalf("Error: can not convert hexadecimal string")
            }
            pub = crypto.ToECDSAPub(b)
            if !isKeyValid(pub) {
                utils.Fatalf("Error: invalid public key")
            }
        }
    }

    if *requestMail {
        p2pAccept = true
        if len(msPassword) == 0 {
            msPassword, err = console.Stdin.PromptPassword("Please enter the Mail Server password: ")
            if err != nil {
                utils.Fatalf("Failed to read Mail Server password: %s", err)
            }
        }
    }

    if !*asymmetricMode && !*forwarderMode {
        if len(symPass) == 0 {
            symPass, err = console.Stdin.PromptPassword("Please enter the password for symmetric encryption: ")
            if err != nil {
                utils.Fatalf("Failed to read passphrase: %v", err)
            }
        }

        symKeyID, err := shh.AddSymKeyFromPassword(symPass)
        if err != nil {
            utils.Fatalf("Failed to create symmetric key: %s", err)
        }
        symKey, err = shh.GetSymKey(symKeyID)
        if err != nil {
            utils.Fatalf("Failed to save symmetric key: %s", err)
        }
        if len(*argTopic) == 0 {
            generateTopic([]byte(symPass))
        }

        fmt.Printf("Filter is configured for the topic: %x \n", topic)
    }

    if *mailServerMode {
        if len(*argDBPath) == 0 {
            argDBPath = scanLineA("Please enter the path to DB file: ")
        }
    }

    symFilter := whisper.Filter{
        KeySym:   symKey,
        Topics:   [][]byte{topic[:]},
        AllowP2P: p2pAccept,
    }
    symFilterID, err = shh.Subscribe(&symFilter)
    if err != nil {
        utils.Fatalf("Failed to install filter: %s", err)
    }

    asymFilter := whisper.Filter{
        KeyAsym:  asymKey,
        Topics:   [][]byte{topic[:]},
        AllowP2P: p2pAccept,
    }
    asymFilterID, err = shh.Subscribe(&asymFilter)
    if err != nil {
        utils.Fatalf("Failed to install filter: %s", err)
    }
}

func generateTopic(password []byte) {
    x := pbkdf2.Key(password, password, 4096, 128, sha512.New)
    for i := 0; i < len(x); i++ {
        topic[i%whisper.TopicLength] ^= x[i]
    }
}

func waitForConnection(timeout bool) {
    var cnt int
    var connected bool
    for !connected {
        time.Sleep(time.Millisecond * 50)
        connected = server.PeerCount() > 0
        if timeout {
            cnt++
            if cnt > 1000 {
                utils.Fatalf("Timeout expired, failed to connect")
            }
        }
    }

    fmt.Println("Connected to peer.")
}

func run() {
    defer mailServer.Close()
    startServer()
    defer server.Stop()
    shh.Start(nil)
    defer shh.Stop()

    if !*forwarderMode {
        go messageLoop()
    }

    if *requestMail {
        requestExpiredMessagesLoop()
    } else if *fileExMode {
        sendFilesLoop()
    } else {
        sendLoop()
    }
}

func sendLoop() {
    for {
        s := scanLine("")
        if s == quitCommand {
            fmt.Println("Quit command received")
            close(done)
            break
        }
        sendMsg([]byte(s))

        if *asymmetricMode {
            // print your own message for convenience,
            // because in asymmetric mode it is impossible to decrypt it
            timestamp := time.Now().Unix()
            from := crypto.PubkeyToAddress(asymKey.PublicKey)
            fmt.Printf("\n%d <%x>: %s\n", timestamp, from, s)
        }
    }
}

func sendFilesLoop() {
    for {
        s := scanLine("")
        if s == quitCommand {
            fmt.Println("Quit command received")
            close(done)
            break
        }
        b, err := ioutil.ReadFile(s)
        if err != nil {
            fmt.Printf(">>> Error: %s \n", err)
            continue
        } else {
            h := sendMsg(b)
            if (h == common.Hash{}) {
                fmt.Printf(">>> Error: message was not sent \n")
            } else {
                timestamp := time.Now().Unix()
                from := crypto.PubkeyToAddress(asymKey.PublicKey)
                fmt.Printf("\n%d <%x>: sent message with hash %x\n", timestamp, from, h)
            }
        }
    }
}

func scanLine(prompt string) string {
    if len(prompt) > 0 {
        fmt.Print(prompt)
    }
    txt, err := input.ReadString('\n')
    if err != nil {
        utils.Fatalf("input error: %s", err)
    }
    txt = strings.TrimRight(txt, "\n\r")
    return txt
}

func scanLineA(prompt string) *string {
    s := scanLine(prompt)
    return &s
}

func scanUint(prompt string) uint32 {
    s := scanLine(prompt)
    i, err := strconv.Atoi(s)
    if err != nil {
        utils.Fatalf("Fail to parse the lower time limit: %s", err)
    }
    return uint32(i)
}

func sendMsg(payload []byte) common.Hash {
    params := whisper.MessageParams{
        Src:      asymKey,
        Dst:      pub,
        KeySym:   symKey,
        Payload:  payload,
        Topic:    topic,
        TTL:      uint32(*argTTL),
        PoW:      *argPoW,
        WorkTime: uint32(*argWorkTime),
    }

    msg, err := whisper.NewSentMessage(&params)
    if err != nil {
        utils.Fatalf("failed to create new message: %s", err)
    }
    envelope, err := msg.Wrap(&params)
    if err != nil {
        fmt.Printf("failed to seal message: %v \n", err)
        return common.Hash{}
    }

    err = shh.Send(envelope)
    if err != nil {
        fmt.Printf("failed to send message: %v \n", err)
        return common.Hash{}
    }

    return envelope.Hash()
}

func messageLoop() {
    sf := shh.GetFilter(symFilterID)
    if sf == nil {
        utils.Fatalf("symmetric filter is not installed")
    }

    af := shh.GetFilter(asymFilterID)
    if af == nil {
        utils.Fatalf("asymmetric filter is not installed")
    }

    ticker := time.NewTicker(time.Millisecond * 50)

    for {
        select {
        case <-ticker.C:
            m1 := sf.Retrieve()
            m2 := af.Retrieve()
            messages := append(m1, m2...)
            for _, msg := range messages {
                // All messages are saved upon specifying argSaveDir.
                // fileExMode only specifies how messages are displayed on the console after they are saved.
                // if fileExMode == true, only the hashes are displayed, since messages might be too big.
                if len(*argSaveDir) > 0 {
                    writeMessageToFile(*argSaveDir, msg)
                }

                if !*fileExMode && len(msg.Payload) <= 2048 {
                    printMessageInfo(msg)
                }
            }
        case <-done:
            return
        }
    }
}

func printMessageInfo(msg *whisper.ReceivedMessage) {
    timestamp := fmt.Sprintf("%d", msg.Sent) // unix timestamp for diagnostics
    text := string(msg.Payload)

    var address common.Address
    if msg.Src != nil {
        address = crypto.PubkeyToAddress(*msg.Src)
    }

    if whisper.IsPubKeyEqual(msg.Src, &asymKey.PublicKey) {
        fmt.Printf("\n%s <%x>: %s\n", timestamp, address, text) // message from myself
    } else {
        fmt.Printf("\n%s [%x]: %s\n", timestamp, address, text) // message from a peer
    }
}

func writeMessageToFile(dir string, msg *whisper.ReceivedMessage) {
    timestamp := fmt.Sprintf("%d", msg.Sent)
    name := fmt.Sprintf("%x", msg.EnvelopeHash)

    var address common.Address
    if msg.Src != nil {
        address = crypto.PubkeyToAddress(*msg.Src)
    }

    // this is a sample code; uncomment if you don't want to save your own messages.
    //if whisper.IsPubKeyEqual(msg.Src, &asymKey.PublicKey) {
    //  fmt.Printf("\n%s <%x>: message from myself received, not saved: '%s'\n", timestamp, address, name)
    //  return
    //}

    if len(dir) > 0 {
        fullpath := filepath.Join(dir, name)
        err := ioutil.WriteFile(fullpath, msg.Raw, 0644)
        if err != nil {
            fmt.Printf("\n%s {%x}: message received but not saved: %s\n", timestamp, address, err)
        } else {
            fmt.Printf("\n%s {%x}: message received and saved as '%s' (%d bytes)\n", timestamp, address, name, len(msg.Raw))
        }
    } else {
        fmt.Printf("\n%s {%x}: message received (%d bytes), but not saved: %s\n", timestamp, address, len(msg.Raw), name)
    }
}

func requestExpiredMessagesLoop() {
    var key, peerID, bloom []byte
    var timeLow, timeUpp uint32
    var t string
    var xt whisper.TopicType

    keyID, err := shh.AddSymKeyFromPassword(msPassword)
    if err != nil {
        utils.Fatalf("Failed to create symmetric key for mail request: %s", err)
    }
    key, err = shh.GetSymKey(keyID)
    if err != nil {
        utils.Fatalf("Failed to save symmetric key for mail request: %s", err)
    }
    peerID = extractIDFromEnode(*argEnode)
    shh.AllowP2PMessagesFromPeer(peerID)

    for {
        timeLow = scanUint("Please enter the lower limit of the time range (unix timestamp): ")
        timeUpp = scanUint("Please enter the upper limit of the time range (unix timestamp): ")
        t = scanLine("Please enter the topic (hexadecimal): ")
        if len(t) >= whisper.TopicLength*2 {
            x, err := hex.DecodeString(t)
            if err != nil {
                utils.Fatalf("Failed to parse the topic: %s", err)
            }
            xt = whisper.BytesToTopic(x)
            bloom = whisper.TopicToBloom(xt)
            obfuscateBloom(bloom)
        } else {
            bloom = whisper.MakeFullNodeBloom()
        }
        if timeUpp == 0 {
            timeUpp = 0xFFFFFFFF
        }

        data := make([]byte, 8, 8+whisper.BloomFilterSize)
        binary.BigEndian.PutUint32(data, timeLow)
        binary.BigEndian.PutUint32(data[4:], timeUpp)
        data = append(data, bloom...)

        var params whisper.MessageParams
        params.PoW = *argServerPoW
        params.Payload = data
        params.KeySym = key
        params.Src = asymKey
        params.WorkTime = 5

        msg, err := whisper.NewSentMessage(&params)
        if err != nil {
            utils.Fatalf("failed to create new message: %s", err)
        }
        env, err := msg.Wrap(&params)
        if err != nil {
            utils.Fatalf("Wrap failed: %s", err)
        }

        err = shh.RequestHistoricMessages(peerID, env)
        if err != nil {
            utils.Fatalf("Failed to send P2P message: %s", err)
        }

        time.Sleep(time.Second * 5)
    }
}

func extractIDFromEnode(s string) []byte {
    n, err := discover.ParseNode(s)
    if err != nil {
        utils.Fatalf("Failed to parse enode: %s", err)
    }
    return n.ID[:]
}

// obfuscateBloom adds 16 random bits to the the bloom
// filter, in order to obfuscate the containing topics.
// it does so deterministically within every session.
// despite additional bits, it will match on average
// 32000 times less messages than full node's bloom filter.
func obfuscateBloom(bloom []byte) {
    const half = entropySize / 2
    for i := 0; i < half; i++ {
        x := int(entropy[i])
        if entropy[half+i] < 128 {
            x += 256
        }

        bloom[x/8] = 1 << uint(x%8) // set the bit number X
    }
}