// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library 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 Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package whisperv6
import (
"bytes"
"crypto/ecdsa"
crand "crypto/rand"
"crypto/sha256"
"fmt"
"runtime"
"sync"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/rpc"
"github.com/syndtr/goleveldb/leveldb/errors"
"golang.org/x/crypto/pbkdf2"
"golang.org/x/sync/syncmap"
set "gopkg.in/fatih/set.v0"
)
type Statistics struct {
messagesCleared int
memoryCleared int
memoryUsed int
cycles int
totalMessagesCleared int
}
const (
minPowIdx = iota // Minimal PoW required by the whisper node
maxMsgSizeIdx = iota // Maximal message length allowed by the whisper node
overflowIdx = iota // Indicator of message queue overflow
)
// Whisper represents a dark communication interface through the Ethereum
// network, using its very own P2P communication layer.
type Whisper struct {
protocol p2p.Protocol // Protocol description and parameters
filters *Filters // Message filters installed with Subscribe function
privateKeys map[string]*ecdsa.PrivateKey // Private key storage
symKeys map[string][]byte // Symmetric key storage
keyMu sync.RWMutex // Mutex associated with key storages
poolMu sync.RWMutex // Mutex to sync the message and expiration pools
envelopes map[common.Hash]*Envelope // Pool of envelopes currently tracked by this node
expirations map[uint32]*set.SetNonTS // Message expiration pool
peerMu sync.RWMutex // Mutex to sync the active peer set
peers map[*Peer]struct{} // Set of currently active peers
messageQueue chan *Envelope // Message queue for normal whisper messages
p2pMsgQueue chan *Envelope // Message queue for peer-to-peer messages (not to be forwarded any further)
quit chan struct{} // Channel used for graceful exit
settings syncmap.Map // holds configuration settings that can be dynamically changed
statsMu sync.Mutex // guard stats
stats Statistics // Statistics of whisper node
mailServer MailServer // MailServer interface
}
// New creates a Whisper client ready to communicate through the Ethereum P2P network.
func New(cfg *Config) *Whisper {
if cfg == nil {
cfg = &DefaultConfig
}
whisper := &Whisper{
privateKeys: make(map[string]*ecdsa.PrivateKey),
symKeys: make(map[string][]byte),
envelopes: make(map[common.Hash]*Envelope),
expirations: make(map[uint32]*set.SetNonTS),
peers: make(map[*Peer]struct{}),
messageQueue: make(chan *Envelope, messageQueueLimit),
p2pMsgQueue: make(chan *Envelope, messageQueueLimit),
quit: make(chan struct{}),
}
whisper.filters = NewFilters(whisper)
whisper.settings.Store(minPowIdx, cfg.MinimumAcceptedPOW)
whisper.settings.Store(maxMsgSizeIdx, cfg.MaxMessageSize)
whisper.settings.Store(overflowIdx, false)
// p2p whisper sub protocol handler
whisper.protocol = p2p.Protocol{
Name: ProtocolName,
Version: uint(ProtocolVersion),
Length: NumberOfMessageCodes,
Run: whisper.HandlePeer,
NodeInfo: func() interface{} {
return map[string]interface{}{
"version": ProtocolVersionStr,
"maxMessageSize": whisper.MaxMessageSize(),
"minimumPoW": whisper.MinPow(),
}
},
}
return whisper
}
func (w *Whisper) MinPow() float64 {
val, _ := w.settings.Load(minPowIdx)
return val.(float64)
}
// MaxMessageSize returns the maximum accepted message size.
func (w *Whisper) MaxMessageSize() uint32 {
val, _ := w.settings.Load(maxMsgSizeIdx)
return val.(uint32)
}
// Overflow returns an indication if the message queue is full.
func (w *Whisper) Overflow() bool {
val, _ := w.settings.Load(overflowIdx)
return val.(bool)
}
// APIs returns the RPC descriptors the Whisper implementation offers
func (w *Whisper) APIs() []rpc.API {
return []rpc.API{
{
Namespace: ProtocolName,
Version: ProtocolVersionStr,
Service: NewPublicWhisperAPI(w),
Public: true,
},
}
}
// RegisterServer registers MailServer interface.
// MailServer will process all the incoming messages with p2pRequestCode.
func (w *Whisper) RegisterServer(server MailServer) {
w.mailServer = server
}
// Protocols returns the whisper sub-protocols ran by this particular client.
func (w *Whisper) Protocols() []p2p.Protocol {
return []p2p.Protocol{w.protocol}
}
// Version returns the whisper sub-protocols version number.
func (w *Whisper) Version() uint {
return w.protocol.Version
}
// SetMaxMessageSize sets the maximal message size allowed by this node
func (w *Whisper) SetMaxMessageSize(size uint32) error {
if size > MaxMessageSize {
return fmt.Errorf("message size too large [%d>%d]", size, MaxMessageSize)
}
w.settings.Store(maxMsgSizeIdx, size)
return nil
}
// SetMinimumPoW sets the minimal PoW required by this node
func (w *Whisper) SetMinimumPoW(val float64) error {
if val <= 0.0 {
return fmt.Errorf("invalid PoW: %f", val)
}
w.settings.Store(minPowIdx, val)
return nil
}
// getPeer retrieves peer by ID
func (w *Whisper) getPeer(peerID []byte) (*Peer, error) {
w.peerMu.Lock()
defer w.peerMu.Unlock()
for p := range w.peers {
id := p.peer.ID()
if bytes.Equal(peerID, id[:]) {
return p, nil
}
}
return nil, fmt.Errorf("Could not find peer with ID: %x", peerID)
}
// AllowP2PMessagesFromPeer marks specific peer trusted,
// which will allow it to send historic (expired) messages.
func (w *Whisper) AllowP2PMessagesFromPeer(peerID []byte) error {
p, err := w.getPeer(peerID)
if err != nil {
return err
}
p.trusted = true
return nil
}
// RequestHistoricMessages sends a message with p2pRequestCode to a specific peer,
// which is known to implement MailServer interface, and is supposed to process this
// request and respond with a number of peer-to-peer messages (possibly expired),
// which are not supposed to be forwarded any further.
// The whisper protocol is agnostic of the format and contents of envelope.
func (w *Whisper) RequestHistoricMessages(peerID []byte, envelope *Envelope) error {
p, err := w.getPeer(peerID)
if err != nil {
return err
}
p.trusted = true
return p2p.Send(p.ws, p2pRequestCode, envelope)
}
// SendP2PMessage sends a peer-to-peer message to a specific peer.
func (w *Whisper) SendP2PMessage(peerID []byte, envelope *Envelope) error {
p, err := w.getPeer(peerID)
if err != nil {
return err
}
return w.SendP2PDirect(p, envelope)
}
// SendP2PDirect sends a peer-to-peer message to a specific peer.
func (w *Whisper) SendP2PDirect(peer *Peer, envelope *Envelope) error {
return p2p.Send(peer.ws, p2pCode, envelope)
}
// NewKeyPair generates a new cryptographic identity for the client, and injects
// it into the known identities for message decryption. Returns ID of the new key pair.
func (w *Whisper) NewKeyPair() (string, error) {
key, err := crypto.GenerateKey()
if err != nil || !validatePrivateKey(key) {
key, err = crypto.GenerateKey() // retry once
}
if err != nil {
return "", err
}
if !validatePrivateKey(key) {
return "", fmt.Errorf("failed to generate valid key")
}
id, err := GenerateRandomID()
if err != nil {
return "", fmt.Errorf("failed to generate ID: %s", err)
}
w.keyMu.Lock()
defer w.keyMu.Unlock()
if w.privateKeys[id] != nil {
return "", fmt.Errorf("failed to generate unique ID")
}
w.privateKeys[id] = key
return id, nil
}
// DeleteKeyPair deletes the specified key if it exists.
func (w *Whisper) DeleteKeyPair(key string) bool {
w.keyMu.Lock()
defer w.keyMu.Unlock()
if w.privateKeys[key] != nil {
delete(w.privateKeys, key)
return true
}
return false
}
// AddKeyPair imports a asymmetric private key and returns it identifier.
func (w *Whisper) AddKeyPair(key *ecdsa.PrivateKey) (string, error) {
id, err := GenerateRandomID()
if err != nil {
return "", fmt.Errorf("failed to generate ID: %s", err)
}
w.keyMu.Lock()
w.privateKeys[id] = key
w.keyMu.Unlock()
return id, nil
}
// HasKeyPair checks if the the whisper node is configured with the private key
// of the specified public pair.
func (w *Whisper) HasKeyPair(id string) bool {
w.keyMu.RLock()
defer w.keyMu.RUnlock()
return w.privateKeys[id] != nil
}
// GetPrivateKey retrieves the private key of the specified identity.
func (w *Whisper) GetPrivateKey(id string) (*ecdsa.PrivateKey, error) {
w.keyMu.RLock()
defer w.keyMu.RUnlock()
key := w.privateKeys[id]
if key == nil {
return nil, fmt.Errorf("invalid id")
}
return key, nil
}
// GenerateSymKey generates a random symmetric key and stores it under id,
// which is then returned. Will be used in the future for session key exchange.
func (w *Whisper) GenerateSymKey() (string, error) {
key := make([]byte, aesKeyLength)
_, err := crand.Read(key)
if err != nil {
return "", err
} else if !validateSymmetricKey(key) {
return "", fmt.Errorf("error in GenerateSymKey: crypto/rand failed to generate random data")
}
id, err := GenerateRandomID()
if err != nil {
return "", fmt.Errorf("failed to generate ID: %s", err)
}
w.keyMu.Lock()
defer w.keyMu.Unlock()
if w.symKeys[id] != nil {
return "", fmt.Errorf("failed to generate unique ID")
}
w.symKeys[id] = key
return id, nil
}
// AddSymKeyDirect stores the key, and returns its id.
func (w *Whisper) AddSymKeyDirect(key []byte) (string, error) {
if len(key) != aesKeyLength {
return "", fmt.Errorf("wrong key size: %d", len(key))
}
id, err := GenerateRandomID()
if err != nil {
return "", fmt.Errorf("failed to generate ID: %s", err)
}
w.keyMu.Lock()
defer w.keyMu.Unlock()
if w.symKeys[id] != nil {
return "", fmt.Errorf("failed to generate unique ID")
}
w.symKeys[id] = key
return id, nil
}
// AddSymKeyFromPassword generates the key from password, stores it, and returns its id.
func (w *Whisper) AddSymKeyFromPassword(password string) (string, error) {
id, err := GenerateRandomID()
if err != nil {
return "", fmt.Errorf("failed to generate ID: %s", err)
}
if w.HasSymKey(id) {
return "", fmt.Errorf("failed to generate unique ID")
}
// kdf should run no less than 0.1 seconds on an average computer,
// because it's an once in a session experience
derived := pbkdf2.Key([]byte(password), nil, 65356, aesKeyLength, sha256.New)
if err != nil {
return "", err
}
w.keyMu.Lock()
defer w.keyMu.Unlock()
// double check is necessary, because deriveKeyMaterial() is very slow
if w.symKeys[id] != nil {
return "", fmt.Errorf("critical error: failed to generate unique ID")
}
w.symKeys[id] = derived
return id, nil
}
// HasSymKey returns true if there is a key associated with the given id.
// Otherwise returns false.
func (w *Whisper) HasSymKey(id string) bool {
w.keyMu.RLock()
defer w.keyMu.RUnlock()
return w.symKeys[id] != nil
}
// DeleteSymKey deletes the key associated with the name string if it exists.
func (w *Whisper) DeleteSymKey(id string) bool {
w.keyMu.Lock()
defer w.keyMu.Unlock()
if w.symKeys[id] != nil {
delete(w.symKeys, id)
return true
}
return false
}
// GetSymKey returns the symmetric key associated with the given id.
func (w *Whisper) GetSymKey(id string) ([]byte, error) {
w.keyMu.RLock()
defer w.keyMu.RUnlock()
if w.symKeys[id] != nil {
return w.symKeys[id], nil
}
return nil, fmt.Errorf("non-existent key ID")
}
// Subscribe installs a new message handler used for filtering, decrypting
// and subsequent storing of incoming messages.
func (w *Whisper) Subscribe(f *Filter) (string, error) {
return w.filters.Install(f)
}
// GetFilter returns the filter by id.
func (w *Whisper) GetFilter(id string) *Filter {
return w.filters.Get(id)
}
// Unsubscribe removes an installed message handler.
func (w *Whisper) Unsubscribe(id string) error {
ok := w.filters.Uninstall(id)
if !ok {
return fmt.Errorf("Unsubscribe: Invalid ID")
}
return nil
}
// Send injects a message into the whisper send queue, to be distributed in the
// network in the coming cycles.
func (w *Whisper) Send(envelope *Envelope) error {
ok, err := w.add(envelope)
if err != nil {
return err
}
if !ok {
return fmt.Errorf("failed to add envelope")
}
return err
}
// Start implements node.Service, starting the background data propagation thread
// of the Whisper protocol.
func (w *Whisper) Start(*p2p.Server) error {
log.Info("started whisper v." + ProtocolVersionStr)
go w.update()
numCPU := runtime.NumCPU()
for i := 0; i < numCPU; i++ {
go w.processQueue()
}
return nil
}
// Stop implements node.Service, stopping the background data propagation thread
// of the Whisper protocol.
func (w *Whisper) Stop() error {
close(w.quit)
log.Info("whisper stopped")
return nil
}
// HandlePeer is called by the underlying P2P layer when the whisper sub-protocol
// connection is negotiated.
func (wh *Whisper) HandlePeer(peer *p2p.Peer, rw p2p.MsgReadWriter) error {
// Create the new peer and start tracking it
whisperPeer := newPeer(wh, peer, rw)
wh.peerMu.Lock()
wh.peers[whisperPeer] = struct{}{}
wh.peerMu.Unlock()
defer func() {
wh.peerMu.Lock()
delete(wh.peers, whisperPeer)
wh.peerMu.Unlock()
}()
// Run the peer handshake and state updates
if err := whisperPeer.handshake(); err != nil {
return err
}
whisperPeer.start()
defer whisperPeer.stop()
return wh.runMessageLoop(whisperPeer, rw)
}
// runMessageLoop reads and processes inbound messages directly to merge into client-global state.
func (wh *Whisper) runMessageLoop(p *Peer, rw p2p.MsgReadWriter) error {
for {
// fetch the next packet
packet, err := rw.ReadMsg()
if err != nil {
log.Warn("message loop", "peer", p.peer.ID(), "err", err)
return err
}
if packet.Size > wh.MaxMessageSize() {
log.Warn("oversized message received", "peer", p.peer.ID())
return errors.New("oversized message received")
}
switch packet.Code {
case statusCode:
// this should not happen, but no need to panic; just ignore this message.
log.Warn("unxepected status message received", "peer", p.peer.ID())
case messagesCode:
// decode the contained envelopes
var envelope Envelope
if err := packet.Decode(&envelope); err != nil {
log.Warn("failed to decode envelope, peer will be disconnected", "peer", p.peer.ID(), "err", err)
return errors.New("invalid envelope")
}
cached, err := wh.add(&envelope)
if err != nil {
log.Warn("bad envelope received, peer will be disconnected", "peer", p.peer.ID(), "err", err)
return errors.New("invalid envelope")
}
if cached {
p.mark(&envelope)
}
case p2pCode:
// peer-to-peer message, sent directly to peer bypassing PoW checks, etc.
// this message is not supposed to be forwarded to other peers, and
// therefore might not satisfy the PoW, expiry and other requirements.
// these messages are only accepted from the trusted peer.
if p.trusted {
var envelope Envelope
if err := packet.Decode(&envelope); err != nil {
log.Warn("failed to decode direct message, peer will be disconnected", "peer", p.peer.ID(), "err", err)
return errors.New("invalid direct message")
}
wh.postEvent(&envelope, true)
}
case p2pRequestCode:
// Must be processed if mail server is implemented. Otherwise ignore.
if wh.mailServer != nil {
var request Envelope
if err := packet.Decode(&request); err != nil {
log.Warn("failed to decode p2p request message, peer will be disconnected", "peer", p.peer.ID(), "err", err)
return errors.New("invalid p2p request")
}
wh.mailServer.DeliverMail(p, &request)
}
default:
// New message types might be implemented in the future versions of Whisper.
// For forward compatibility, just ignore.
}
packet.Discard()
}
}
// add inserts a new envelope into the message pool to be distributed within the
// whisper network. It also inserts the envelope into the expiration pool at the
// appropriate time-stamp. In case of error, connection should be dropped.
func (wh *Whisper) add(envelope *Envelope) (bool, error) {
now := uint32(time.Now().Unix())
sent := envelope.Expiry - envelope.TTL
if sent > now {
if sent-SynchAllowance > now {
return false, fmt.Errorf("envelope created in the future [%x]", envelope.Hash())
} else {
// recalculate PoW, adjusted for the time difference, plus one second for latency
envelope.calculatePoW(sent - now + 1)
}
}
if envelope.Expiry < now {
if envelope.Expiry+SynchAllowance*2 < now {
return false, fmt.Errorf("very old message")
} else {
log.Debug("expired envelope dropped", "hash", envelope.Hash().Hex())
return false, nil // drop envelope without error
}
}
if uint32(envelope.size()) > wh.MaxMessageSize() {
return false, fmt.Errorf("huge messages are not allowed [%x]", envelope.Hash())
}
if envelope.PoW() < wh.MinPow() {
log.Debug("envelope with low PoW dropped", "PoW", envelope.PoW(), "hash", envelope.Hash().Hex())
return false, nil // drop envelope without error
}
hash := envelope.Hash()
wh.poolMu.Lock()
_, alreadyCached := wh.envelopes[hash]
if !alreadyCached {
wh.envelopes[hash] = envelope
if wh.expirations[envelope.Expiry] == nil {
wh.expirations[envelope.Expiry] = set.NewNonTS()
}
if !wh.expirations[envelope.Expiry].Has(hash) {
wh.expirations[envelope.Expiry].Add(hash)
}
}
wh.poolMu.Unlock()
if alreadyCached {
log.Trace("whisper envelope already cached", "hash", envelope.Hash().Hex())
} else {
log.Trace("cached whisper envelope", "hash", envelope.Hash().Hex())
wh.statsMu.Lock()
wh.stats.memoryUsed += envelope.size()
wh.statsMu.Unlock()
wh.postEvent(envelope, false) // notify the local node about the new message
if wh.mailServer != nil {
wh.mailServer.Archive(envelope)
}
}
return true, nil
}
// postEvent queues the message for further processing.
func (w *Whisper) postEvent(envelope *Envelope, isP2P bool) {
if isP2P {
w.p2pMsgQueue <- envelope
} else {
w.checkOverflow()
w.messageQueue <- envelope
}
}
// checkOverflow checks if message queue overflow occurs and reports it if necessary.
func (w *Whisper) checkOverflow() {
queueSize := len(w.messageQueue)
if queueSize == messageQueueLimit {
if !w.Overflow() {
w.settings.Store(overflowIdx, true)
log.Warn("message queue overflow")
}
} else if queueSize <= messageQueueLimit/2 {
if w.Overflow() {
w.settings.Store(overflowIdx, false)
log.Warn("message queue overflow fixed (back to normal)")
}
}
}
// processQueue delivers the messages to the watchers during the lifetime of the whisper node.
func (w *Whisper) processQueue() {
var e *Envelope
for {
select {
case <-w.quit:
return
case e = <-w.messageQueue:
w.filters.NotifyWatchers(e, false)
case e = <-w.p2pMsgQueue:
w.filters.NotifyWatchers(e, true)
}
}
}
// update loops until the lifetime of the whisper node, updating its internal
// state by expiring stale messages from the pool.
func (w *Whisper) update() {
// Start a ticker to check for expirations
expire := time.NewTicker(expirationCycle)
// Repeat updates until termination is requested
for {
select {
case <-expire.C:
w.expire()
case <-w.quit:
return
}
}
}
// expire iterates over all the expiration timestamps, removing all stale
// messages from the pools.
func (w *Whisper) expire() {
w.poolMu.Lock()
defer w.poolMu.Unlock()
w.statsMu.Lock()
defer w.statsMu.Unlock()
w.stats.reset()
now := uint32(time.Now().Unix())
for expiry, hashSet := range w.expirations {
if expiry < now {
// Dump all expired messages and remove timestamp
hashSet.Each(func(v interface{}) bool {
sz := w.envelopes[v.(common.Hash)].size()
delete(w.envelopes, v.(common.Hash))
w.stats.messagesCleared++
w.stats.memoryCleared += sz
w.stats.memoryUsed -= sz
return true
})
w.expirations[expiry].Clear()
delete(w.expirations, expiry)
}
}
}
// Stats returns the whisper node statistics.
func (w *Whisper) Stats() Statistics {
w.statsMu.Lock()
defer w.statsMu.Unlock()
return w.stats
}
// Envelopes retrieves all the messages currently pooled by the node.
func (w *Whisper) Envelopes() []*Envelope {
w.poolMu.RLock()
defer w.poolMu.RUnlock()
all := make([]*Envelope, 0, len(w.envelopes))
for _, envelope := range w.envelopes {
all = append(all, envelope)
}
return all
}
// Messages iterates through all currently floating envelopes
// and retrieves all the messages, that this filter could decrypt.
func (w *Whisper) Messages(id string) []*ReceivedMessage {
result := make([]*ReceivedMessage, 0)
w.poolMu.RLock()
defer w.poolMu.RUnlock()
if filter := w.filters.Get(id); filter != nil {
for _, env := range w.envelopes {
msg := filter.processEnvelope(env)
if msg != nil {
result = append(result, msg)
}
}
}
return result
}
// isEnvelopeCached checks if envelope with specific hash has already been received and cached.
func (w *Whisper) isEnvelopeCached(hash common.Hash) bool {
w.poolMu.Lock()
defer w.poolMu.Unlock()
_, exist := w.envelopes[hash]
return exist
}
// reset resets the node's statistics after each expiry cycle.
func (s *Statistics) reset() {
s.cycles++
s.totalMessagesCleared += s.messagesCleared
s.memoryCleared = 0
s.messagesCleared = 0
}
// ValidatePublicKey checks the format of the given public key.
func ValidatePublicKey(k *ecdsa.PublicKey) bool {
return k != nil && k.X != nil && k.Y != nil && k.X.Sign() != 0 && k.Y.Sign() != 0
}
// validatePrivateKey checks the format of the given private key.
func validatePrivateKey(k *ecdsa.PrivateKey) bool {
if k == nil || k.D == nil || k.D.Sign() == 0 {
return false
}
return ValidatePublicKey(&k.PublicKey)
}
// validateSymmetricKey returns false if the key contains all zeros
func validateSymmetricKey(k []byte) bool {
return len(k) > 0 && !containsOnlyZeros(k)
}
// containsOnlyZeros checks if the data contain only zeros.
func containsOnlyZeros(data []byte) bool {
for _, b := range data {
if b != 0 {
return false
}
}
return true
}
// bytesToUintLittleEndian converts the slice to 64-bit unsigned integer.
func bytesToUintLittleEndian(b []byte) (res uint64) {
mul := uint64(1)
for i := 0; i < len(b); i++ {
res += uint64(b[i]) * mul
mul *= 256
}
return res
}
// BytesToUintBigEndian converts the slice to 64-bit unsigned integer.
func BytesToUintBigEndian(b []byte) (res uint64) {
for i := 0; i < len(b); i++ {
res *= 256
res += uint64(b[i])
}
return res
}
// GenerateRandomID generates a random string, which is then returned to be used as a key id
func GenerateRandomID() (id string, err error) {
buf := make([]byte, keyIdSize)
_, err = crand.Read(buf)
if err != nil {
return "", err
}
if !validateSymmetricKey(buf) {
return "", fmt.Errorf("error in generateRandomID: crypto/rand failed to generate random data")
}
id = common.Bytes2Hex(buf)
return id, err
}
