// Copyright 2018 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 pss
import (
"bytes"
"context"
"crypto/ecdsa"
"crypto/rand"
"errors"
"fmt"
"sync"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/metrics"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/p2p/enode"
"github.com/ethereum/go-ethereum/p2p/protocols"
"github.com/ethereum/go-ethereum/rpc"
"github.com/ethereum/go-ethereum/swarm/log"
"github.com/ethereum/go-ethereum/swarm/network"
"github.com/ethereum/go-ethereum/swarm/pot"
"github.com/ethereum/go-ethereum/swarm/storage"
whisper "github.com/ethereum/go-ethereum/whisper/whisperv5"
)
const (
defaultPaddingByteSize = 16
DefaultMsgTTL = time.Second * 120
defaultDigestCacheTTL = time.Second * 10
defaultSymKeyCacheCapacity = 512
digestLength = 32 // byte length of digest used for pss cache (currently same as swarm chunk hash)
defaultWhisperWorkTime = 3
defaultWhisperPoW = 0.0000000001
defaultMaxMsgSize = 1024 * 1024
defaultCleanInterval = time.Second * 60 * 10
defaultOutboxCapacity = 100000
pssProtocolName = "pss"
pssVersion = 2
hasherCount = 8
)
var (
addressLength = len(pot.Address{})
)
// cache is used for preventing backwards routing
// will also be instrumental in flood guard mechanism
// and mailbox implementation
type pssCacheEntry struct {
expiresAt time.Time
}
// abstraction to enable access to p2p.protocols.Peer.Send
type senderPeer interface {
Info() *p2p.PeerInfo
ID() enode.ID
Address() []byte
Send(context.Context, interface{}) error
}
// per-key peer related information
// member `protected` prevents garbage collection of the instance
type pssPeer struct {
lastSeen time.Time
address *PssAddress
protected bool
}
// Pss configuration parameters
type PssParams struct {
MsgTTL time.Duration
CacheTTL time.Duration
privateKey *ecdsa.PrivateKey
SymKeyCacheCapacity int
AllowRaw bool // If true, enables sending and receiving messages without builtin pss encryption
}
// Sane defaults for Pss
func NewPssParams() *PssParams {
return &PssParams{
MsgTTL: DefaultMsgTTL,
CacheTTL: defaultDigestCacheTTL,
SymKeyCacheCapacity: defaultSymKeyCacheCapacity,
}
}
func (params *PssParams) WithPrivateKey(privatekey *ecdsa.PrivateKey) *PssParams {
params.privateKey = privatekey
return params
}
// Toplevel pss object, takes care of message sending, receiving, decryption and encryption, message handler dispatchers and message forwarding.
//
// Implements node.Service
type Pss struct {
*network.Kademlia // we can get the Kademlia address from this
privateKey *ecdsa.PrivateKey // pss can have it's own independent key
w *whisper.Whisper // key and encryption backend
auxAPIs []rpc.API // builtins (handshake, test) can add APIs
// sending and forwarding
fwdPool map[string]*protocols.Peer // keep track of all peers sitting on the pssmsg routing layer
fwdPoolMu sync.RWMutex
fwdCache map[pssDigest]pssCacheEntry // checksum of unique fields from pssmsg mapped to expiry, cache to determine whether to drop msg
fwdCacheMu sync.RWMutex
cacheTTL time.Duration // how long to keep messages in fwdCache (not implemented)
msgTTL time.Duration
paddingByteSize int
capstring string
outbox chan *PssMsg
// keys and peers
pubKeyPool map[string]map[Topic]*pssPeer // mapping of hex public keys to peer address by topic.
pubKeyPoolMu sync.RWMutex
symKeyPool map[string]map[Topic]*pssPeer // mapping of symkeyids to peer address by topic.
symKeyPoolMu sync.RWMutex
symKeyDecryptCache []*string // fast lookup of symkeys recently used for decryption; last used is on top of stack
symKeyDecryptCacheCursor int // modular cursor pointing to last used, wraps on symKeyDecryptCache array
symKeyDecryptCacheCapacity int // max amount of symkeys to keep.
// message handling
handlers map[Topic]map[*Handler]bool // topic and version based pss payload handlers. See pss.Handle()
handlersMu sync.RWMutex
allowRaw bool
hashPool sync.Pool
// process
quitC chan struct{}
}
func (p *Pss) String() string {
return fmt.Sprintf("pss: addr %x, pubkey %v", p.BaseAddr(), common.ToHex(crypto.FromECDSAPub(&p.privateKey.PublicKey)))
}
// Creates a new Pss instance.
//
// In addition to params, it takes a swarm network Kademlia
// and a FileStore storage for message cache storage.
func NewPss(k *network.Kademlia, params *PssParams) (*Pss, error) {
if params.privateKey == nil {
return nil, errors.New("missing private key for pss")
}
cap := p2p.Cap{
Name: pssProtocolName,
Version: pssVersion,
}
ps := &Pss{
Kademlia: k,
privateKey: params.privateKey,
w: whisper.New(&whisper.DefaultConfig),
quitC: make(chan struct{}),
fwdPool: make(map[string]*protocols.Peer),
fwdCache: make(map[pssDigest]pssCacheEntry),
cacheTTL: params.CacheTTL,
msgTTL: params.MsgTTL,
paddingByteSize: defaultPaddingByteSize,
capstring: cap.String(),
outbox: make(chan *PssMsg, defaultOutboxCapacity),
pubKeyPool: make(map[string]map[Topic]*pssPeer),
symKeyPool: make(map[string]map[Topic]*pssPeer),
symKeyDecryptCache: make([]*string, params.SymKeyCacheCapacity),
symKeyDecryptCacheCapacity: params.SymKeyCacheCapacity,
handlers: make(map[Topic]map[*Handler]bool),
allowRaw: params.AllowRaw,
hashPool: sync.Pool{
New: func() interface{} {
return storage.MakeHashFunc(storage.DefaultHash)()
},
},
}
for i := 0; i < hasherCount; i++ {
hashfunc := storage.MakeHashFunc(storage.DefaultHash)()
ps.hashPool.Put(hashfunc)
}
return ps, nil
}
/////////////////////////////////////////////////////////////////////
// SECTION: node.Service interface
/////////////////////////////////////////////////////////////////////
func (p *Pss) Start(srv *p2p.Server) error {
go func() {
ticker := time.NewTicker(defaultCleanInterval)
cacheTicker := time.NewTicker(p.cacheTTL)
defer ticker.Stop()
defer cacheTicker.Stop()
for {
select {
case <-cacheTicker.C:
p.cleanFwdCache()
case <-ticker.C:
p.cleanKeys()
case <-p.quitC:
return
}
}
}()
go func() {
for {
select {
case msg := <-p.outbox:
err := p.forward(msg)
if err != nil {
log.Error(err.Error())
metrics.GetOrRegisterCounter("pss.forward.err", nil).Inc(1)
}
case <-p.quitC:
return
}
}
}()
log.Info("Started Pss")
log.Info("Loaded EC keys", "pubkey", common.ToHex(crypto.FromECDSAPub(p.PublicKey())), "secp256", common.ToHex(crypto.CompressPubkey(p.PublicKey())))
return nil
}
func (p *Pss) Stop() error {
log.Info("Pss shutting down")
close(p.quitC)
return nil
}
var pssSpec = &protocols.Spec{
Name: pssProtocolName,
Version: pssVersion,
MaxMsgSize: defaultMaxMsgSize,
Messages: []interface{}{
PssMsg{},
},
}
func (p *Pss) Protocols() []p2p.Protocol {
return []p2p.Protocol{
{
Name: pssSpec.Name,
Version: pssSpec.Version,
Length: pssSpec.Length(),
Run: p.Run,
},
}
}
func (p *Pss) Run(peer *p2p.Peer, rw p2p.MsgReadWriter) error {
pp := protocols.NewPeer(peer, rw, pssSpec)
p.fwdPoolMu.Lock()
p.fwdPool[peer.Info().ID] = pp
p.fwdPoolMu.Unlock()
return pp.Run(p.handlePssMsg)
}
func (p *Pss) APIs() []rpc.API {
apis := []rpc.API{
{
Namespace: "pss",
Version: "1.0",
Service: NewAPI(p),
Public: true,
},
}
apis = append(apis, p.auxAPIs...)
return apis
}
// add API methods to the pss API
// must be run before node is started
func (p *Pss) addAPI(api rpc.API) {
p.auxAPIs = append(p.auxAPIs, api)
}
// Returns the swarm Kademlia address of the pss node
func (p *Pss) BaseAddr() []byte {
return p.Kademlia.BaseAddr()
}
// Returns the pss node's public key
func (p *Pss) PublicKey() *ecdsa.PublicKey {
return &p.privateKey.PublicKey
}
/////////////////////////////////////////////////////////////////////
// SECTION: Message handling
/////////////////////////////////////////////////////////////////////
// Links a handler function to a Topic
//
// All incoming messages with an envelope Topic matching the
// topic specified will be passed to the given Handler function.
//
// There may be an arbitrary number of handler functions per topic.
//
// Returns a deregister function which needs to be called to
// deregister the handler,
func (p *Pss) Register(topic *Topic, handler Handler) func() {
p.handlersMu.Lock()
defer p.handlersMu.Unlock()
handlers := p.handlers[*topic]
if handlers == nil {
handlers = make(map[*Handler]bool)
p.handlers[*topic] = handlers
}
handlers[&handler] = true
return func() { p.deregister(topic, &handler) }
}
func (p *Pss) deregister(topic *Topic, h *Handler) {
p.handlersMu.Lock()
defer p.handlersMu.Unlock()
handlers := p.handlers[*topic]
if len(handlers) == 1 {
delete(p.handlers, *topic)
return
}
delete(handlers, h)
}
// get all registered handlers for respective topics
func (p *Pss) getHandlers(topic Topic) map[*Handler]bool {
p.handlersMu.RLock()
defer p.handlersMu.RUnlock()
return p.handlers[topic]
}
// Filters incoming messages for processing or forwarding.
// Check if address partially matches
// If yes, it CAN be for us, and we process it
// Only passes error to pss protocol handler if payload is not valid pssmsg
func (p *Pss) handlePssMsg(ctx context.Context, msg interface{}) error {
metrics.GetOrRegisterCounter("pss.handlepssmsg", nil).Inc(1)
pssmsg, ok := msg.(*PssMsg)
if !ok {
return fmt.Errorf("invalid message type. Expected *PssMsg, got %T ", msg)
}
if int64(pssmsg.Expire) < time.Now().Unix() {
metrics.GetOrRegisterCounter("pss.expire", nil).Inc(1)
log.Warn("pss filtered expired message", "from", common.ToHex(p.Kademlia.BaseAddr()), "to", common.ToHex(pssmsg.To))
return nil
}
if p.checkFwdCache(pssmsg) {
log.Trace("pss relay block-cache match (process)", "from", common.ToHex(p.Kademlia.BaseAddr()), "to", (common.ToHex(pssmsg.To)))
return nil
}
p.addFwdCache(pssmsg)
if !p.isSelfPossibleRecipient(pssmsg) {
log.Trace("pss was for someone else :'( ... forwarding", "pss", common.ToHex(p.BaseAddr()))
return p.enqueue(pssmsg)
}
log.Trace("pss for us, yay! ... let's process!", "pss", common.ToHex(p.BaseAddr()))
if err := p.process(pssmsg); err != nil {
qerr := p.enqueue(pssmsg)
if qerr != nil {
return fmt.Errorf("process fail: processerr %v, queueerr: %v", err, qerr)
}
}
return nil
}
// Entry point to processing a message for which the current node can be the intended recipient.
// Attempts symmetric and asymmetric decryption with stored keys.
// Dispatches message to all handlers matching the message topic
func (p *Pss) process(pssmsg *PssMsg) error {
metrics.GetOrRegisterCounter("pss.process", nil).Inc(1)
var err error
var recvmsg *whisper.ReceivedMessage
var payload []byte
var from *PssAddress
var asymmetric bool
var keyid string
var keyFunc func(envelope *whisper.Envelope) (*whisper.ReceivedMessage, string, *PssAddress, error)
envelope := pssmsg.Payload
psstopic := Topic(envelope.Topic)
if pssmsg.isRaw() {
if !p.allowRaw {
return errors.New("raw message support disabled")
}
payload = pssmsg.Payload.Data
} else {
if pssmsg.isSym() {
keyFunc = p.processSym
} else {
asymmetric = true
keyFunc = p.processAsym
}
recvmsg, keyid, from, err = keyFunc(envelope)
if err != nil {
return errors.New("Decryption failed")
}
payload = recvmsg.Payload
}
if len(pssmsg.To) < addressLength {
if err := p.enqueue(pssmsg); err != nil {
return err
}
}
p.executeHandlers(psstopic, payload, from, asymmetric, keyid)
return nil
}
func (p *Pss) executeHandlers(topic Topic, payload []byte, from *PssAddress, asymmetric bool, keyid string) {
handlers := p.getHandlers(topic)
peer := p2p.NewPeer(enode.ID{}, fmt.Sprintf("%x", from), []p2p.Cap{})
for f := range handlers {
err := (*f)(payload, peer, asymmetric, keyid)
if err != nil {
log.Warn("Pss handler %p failed: %v", f, err)
}
}
}
// will return false if using partial address
func (p *Pss) isSelfRecipient(msg *PssMsg) bool {
return bytes.Equal(msg.To, p.Kademlia.BaseAddr())
}
// test match of leftmost bytes in given message to node's Kademlia address
func (p *Pss) isSelfPossibleRecipient(msg *PssMsg) bool {
local := p.Kademlia.BaseAddr()
return bytes.Equal(msg.To, local[:len(msg.To)])
}
/////////////////////////////////////////////////////////////////////
// SECTION: Encryption
/////////////////////////////////////////////////////////////////////
// Links a peer ECDSA public key to a topic
//
// This is required for asymmetric message exchange
// on the given topic
//
// The value in `address` will be used as a routing hint for the
// public key / topic association
func (p *Pss) SetPeerPublicKey(pubkey *ecdsa.PublicKey, topic Topic, address *PssAddress) error {
pubkeybytes := crypto.FromECDSAPub(pubkey)
if len(pubkeybytes) == 0 {
return fmt.Errorf("invalid public key: %v", pubkey)
}
pubkeyid := common.ToHex(pubkeybytes)
psp := &pssPeer{
address: address,
}
p.pubKeyPoolMu.Lock()
if _, ok := p.pubKeyPool[pubkeyid]; !ok {
p.pubKeyPool[pubkeyid] = make(map[Topic]*pssPeer)
}
p.pubKeyPool[pubkeyid][topic] = psp
p.pubKeyPoolMu.Unlock()
log.Trace("added pubkey", "pubkeyid", pubkeyid, "topic", topic, "address", common.ToHex(*address))
return nil
}
// Automatically generate a new symkey for a topic and address hint
func (p *Pss) GenerateSymmetricKey(topic Topic, address *PssAddress, addToCache bool) (string, error) {
keyid, err := p.w.GenerateSymKey()
if err != nil {
return "", err
}
p.addSymmetricKeyToPool(keyid, topic, address, addToCache, false)
return keyid, nil
}
// Links a peer symmetric key (arbitrary byte sequence) to a topic
//
// This is required for symmetrically encrypted message exchange
// on the given topic
//
// The key is stored in the whisper backend.
//
// If addtocache is set to true, the key will be added to the cache of keys
// used to attempt symmetric decryption of incoming messages.
//
// Returns a string id that can be used to retrieve the key bytes
// from the whisper backend (see pss.GetSymmetricKey())
func (p *Pss) SetSymmetricKey(key []byte, topic Topic, address *PssAddress, addtocache bool) (string, error) {
return p.setSymmetricKey(key, topic, address, addtocache, true)
}
func (p *Pss) setSymmetricKey(key []byte, topic Topic, address *PssAddress, addtocache bool, protected bool) (string, error) {
keyid, err := p.w.AddSymKeyDirect(key)
if err != nil {
return "", err
}
p.addSymmetricKeyToPool(keyid, topic, address, addtocache, protected)
return keyid, nil
}
// adds a symmetric key to the pss key pool, and optionally adds the key
// to the collection of keys used to attempt symmetric decryption of
// incoming messages
func (p *Pss) addSymmetricKeyToPool(keyid string, topic Topic, address *PssAddress, addtocache bool, protected bool) {
psp := &pssPeer{
address: address,
protected: protected,
}
p.symKeyPoolMu.Lock()
if _, ok := p.symKeyPool[keyid]; !ok {
p.symKeyPool[keyid] = make(map[Topic]*pssPeer)
}
p.symKeyPool[keyid][topic] = psp
p.symKeyPoolMu.Unlock()
if addtocache {
p.symKeyDecryptCacheCursor++
p.symKeyDecryptCache[p.symKeyDecryptCacheCursor%cap(p.symKeyDecryptCache)] = &keyid
}
key, _ := p.GetSymmetricKey(keyid)
log.Trace("added symkey", "symkeyid", keyid, "symkey", common.ToHex(key), "topic", topic, "address", fmt.Sprintf("%p", address), "cache", addtocache)
}
// Returns a symmetric key byte seqyence stored in the whisper backend
// by its unique id
//
// Passes on the error value from the whisper backend
func (p *Pss) GetSymmetricKey(symkeyid string) ([]byte, error) {
symkey, err := p.w.GetSymKey(symkeyid)
if err != nil {
return nil, err
}
return symkey, nil
}
// Returns all recorded topic and address combination for a specific public key
func (p *Pss) GetPublickeyPeers(keyid string) (topic []Topic, address []PssAddress, err error) {
p.pubKeyPoolMu.RLock()
defer p.pubKeyPoolMu.RUnlock()
for t, peer := range p.pubKeyPool[keyid] {
topic = append(topic, t)
address = append(address, *peer.address)
}
return topic, address, nil
}
func (p *Pss) getPeerAddress(keyid string, topic Topic) (PssAddress, error) {
p.pubKeyPoolMu.RLock()
defer p.pubKeyPoolMu.RUnlock()
if peers, ok := p.pubKeyPool[keyid]; ok {
if t, ok := peers[topic]; ok {
return *t.address, nil
}
}
return nil, fmt.Errorf("peer with pubkey %s, topic %x not found", keyid, topic)
}
// Attempt to decrypt, validate and unpack a
// symmetrically encrypted message
// If successful, returns the unpacked whisper ReceivedMessage struct
// encapsulating the decrypted message, and the whisper backend id
// of the symmetric key used to decrypt the message.
// It fails if decryption of the message fails or if the message is corrupted
func (p *Pss) processSym(envelope *whisper.Envelope) (*whisper.ReceivedMessage, string, *PssAddress, error) {
metrics.GetOrRegisterCounter("pss.process.sym", nil).Inc(1)
for i := p.symKeyDecryptCacheCursor; i > p.symKeyDecryptCacheCursor-cap(p.symKeyDecryptCache) && i > 0; i-- {
symkeyid := p.symKeyDecryptCache[i%cap(p.symKeyDecryptCache)]
symkey, err := p.w.GetSymKey(*symkeyid)
if err != nil {
continue
}
recvmsg, err := envelope.OpenSymmetric(symkey)
if err != nil {
continue
}
if !recvmsg.Validate() {
return nil, "", nil, fmt.Errorf("symmetrically encrypted message has invalid signature or is corrupt")
}
p.symKeyPoolMu.Lock()
from := p.symKeyPool[*symkeyid][Topic(envelope.Topic)].address
p.symKeyPoolMu.Unlock()
p.symKeyDecryptCacheCursor++
p.symKeyDecryptCache[p.symKeyDecryptCacheCursor%cap(p.symKeyDecryptCache)] = symkeyid
return recvmsg, *symkeyid, from, nil
}
return nil, "", nil, fmt.Errorf("could not decrypt message")
}
// Attempt to decrypt, validate and unpack an
// asymmetrically encrypted message
// If successful, returns the unpacked whisper ReceivedMessage struct
// encapsulating the decrypted message, and the byte representation of
// the public key used to decrypt the message.
// It fails if decryption of message fails, or if the message is corrupted
func (p *Pss) processAsym(envelope *whisper.Envelope) (*whisper.ReceivedMessage, string, *PssAddress, error) {
metrics.GetOrRegisterCounter("pss.process.asym", nil).Inc(1)
recvmsg, err := envelope.OpenAsymmetric(p.privateKey)
if err != nil {
return nil, "", nil, fmt.Errorf("could not decrypt message: %s", err)
}
// check signature (if signed), strip padding
if !recvmsg.Validate() {
return nil, "", nil, fmt.Errorf("invalid message")
}
pubkeyid := common.ToHex(crypto.FromECDSAPub(recvmsg.Src))
var from *PssAddress
p.pubKeyPoolMu.Lock()
if p.pubKeyPool[pubkeyid][Topic(envelope.Topic)] != nil {
from = p.pubKeyPool[pubkeyid][Topic(envelope.Topic)].address
}
p.pubKeyPoolMu.Unlock()
return recvmsg, pubkeyid, from, nil
}
// Symkey garbage collection
// a key is removed if:
// - it is not marked as protected
// - it is not in the incoming decryption cache
func (p *Pss) cleanKeys() (count int) {
for keyid, peertopics := range p.symKeyPool {
var expiredtopics []Topic
for topic, psp := range peertopics {
if psp.protected {
continue
}
var match bool
for i := p.symKeyDecryptCacheCursor; i > p.symKeyDecryptCacheCursor-cap(p.symKeyDecryptCache) && i > 0; i-- {
cacheid := p.symKeyDecryptCache[i%cap(p.symKeyDecryptCache)]
if *cacheid == keyid {
match = true
}
}
if !match {
expiredtopics = append(expiredtopics, topic)
}
}
for _, topic := range expiredtopics {
p.symKeyPoolMu.Lock()
delete(p.symKeyPool[keyid], topic)
log.Trace("symkey cleanup deletion", "symkeyid", keyid, "topic", topic, "val", p.symKeyPool[keyid])
p.symKeyPoolMu.Unlock()
count++
}
}
return
}
/////////////////////////////////////////////////////////////////////
// SECTION: Message sending
/////////////////////////////////////////////////////////////////////
func (p *Pss) enqueue(msg *PssMsg) error {
select {
case p.outbox <- msg:
return nil
default:
}
metrics.GetOrRegisterCounter("pss.enqueue.outbox.full", nil).Inc(1)
return errors.New("outbox full")
}
// Send a raw message (any encryption is responsibility of calling client)
//
// Will fail if raw messages are disallowed
func (p *Pss) SendRaw(address PssAddress, topic Topic, msg []byte) error {
if !p.allowRaw {
return errors.New("Raw messages not enabled")
}
pssMsgParams := &msgParams{
raw: true,
}
payload := &whisper.Envelope{
Data: msg,
Topic: whisper.TopicType(topic),
}
pssMsg := newPssMsg(pssMsgParams)
pssMsg.To = address
pssMsg.Expire = uint32(time.Now().Add(p.msgTTL).Unix())
pssMsg.Payload = payload
p.addFwdCache(pssMsg)
return p.enqueue(pssMsg)
}
// Send a message using symmetric encryption
//
// Fails if the key id does not match any of the stored symmetric keys
func (p *Pss) SendSym(symkeyid string, topic Topic, msg []byte) error {
symkey, err := p.GetSymmetricKey(symkeyid)
if err != nil {
return fmt.Errorf("missing valid send symkey %s: %v", symkeyid, err)
}
p.symKeyPoolMu.Lock()
psp, ok := p.symKeyPool[symkeyid][topic]
p.symKeyPoolMu.Unlock()
if !ok {
return fmt.Errorf("invalid topic '%s' for symkey '%s'", topic.String(), symkeyid)
} else if psp.address == nil {
return fmt.Errorf("no address hint for topic '%s' symkey '%s'", topic.String(), symkeyid)
}
err = p.send(*psp.address, topic, msg, false, symkey)
return err
}
// Send a message using asymmetric encryption
//
// Fails if the key id does not match any in of the stored public keys
func (p *Pss) SendAsym(pubkeyid string, topic Topic, msg []byte) error {
if _, err := crypto.UnmarshalPubkey(common.FromHex(pubkeyid)); err != nil {
return fmt.Errorf("Cannot unmarshal pubkey: %x", pubkeyid)
}
p.pubKeyPoolMu.Lock()
psp, ok := p.pubKeyPool[pubkeyid][topic]
p.pubKeyPoolMu.Unlock()
if !ok {
return fmt.Errorf("invalid topic '%s' for pubkey '%s'", topic.String(), pubkeyid)
} else if psp.address == nil {
return fmt.Errorf("no address hint for topic '%s' pubkey '%s'", topic.String(), pubkeyid)
}
go func() {
p.send(*psp.address, topic, msg, true, common.FromHex(pubkeyid))
}()
return nil
}
// Send is payload agnostic, and will accept any byte slice as payload
// It generates an whisper envelope for the specified recipient and topic,
// and wraps the message payload in it.
// TODO: Implement proper message padding
func (p *Pss) send(to []byte, topic Topic, msg []byte, asymmetric bool, key []byte) error {
metrics.GetOrRegisterCounter("pss.send", nil).Inc(1)
if key == nil || bytes.Equal(key, []byte{}) {
return fmt.Errorf("Zero length key passed to pss send")
}
padding := make([]byte, p.paddingByteSize)
c, err := rand.Read(padding)
if err != nil {
return err
} else if c < p.paddingByteSize {
return fmt.Errorf("invalid padding length: %d", c)
}
wparams := &whisper.MessageParams{
TTL: defaultWhisperTTL,
Src: p.privateKey,
Topic: whisper.TopicType(topic),
WorkTime: defaultWhisperWorkTime,
PoW: defaultWhisperPoW,
Payload: msg,
Padding: padding,
}
if asymmetric {
pk, err := crypto.UnmarshalPubkey(key)
if err != nil {
return fmt.Errorf("Cannot unmarshal pubkey: %x", key)
}
wparams.Dst = pk
} else {
wparams.KeySym = key
}
// set up outgoing message container, which does encryption and envelope wrapping
woutmsg, err := whisper.NewSentMessage(wparams)
if err != nil {
return fmt.Errorf("failed to generate whisper message encapsulation: %v", err)
}
// performs encryption.
// Does NOT perform / performs negligible PoW due to very low difficulty setting
// after this the message is ready for sending
envelope, err := woutmsg.Wrap(wparams)
if err != nil {
return fmt.Errorf("failed to perform whisper encryption: %v", err)
}
log.Trace("pssmsg whisper done", "env", envelope, "wparams payload", common.ToHex(wparams.Payload), "to", common.ToHex(to), "asym", asymmetric, "key", common.ToHex(key))
// prepare for devp2p transport
pssMsgParams := &msgParams{
sym: !asymmetric,
}
pssMsg := newPssMsg(pssMsgParams)
pssMsg.To = to
pssMsg.Expire = uint32(time.Now().Add(p.msgTTL).Unix())
pssMsg.Payload = envelope
return p.enqueue(pssMsg)
}
// Forwards a pss message to the peer(s) closest to the to recipient address in the PssMsg struct
// The recipient address can be of any length, and the byte slice will be matched to the MSB slice
// of the peer address of the equivalent length.
func (p *Pss) forward(msg *PssMsg) error {
metrics.GetOrRegisterCounter("pss.forward", nil).Inc(1)
to := make([]byte, addressLength)
copy(to[:len(msg.To)], msg.To)
// send with kademlia
// find the closest peer to the recipient and attempt to send
sent := 0
p.Kademlia.EachConn(to, 256, func(sp *network.Peer, po int, isproxbin bool) bool {
info := sp.Info()
// check if the peer is running pss
var ispss bool
for _, cap := range info.Caps {
if cap == p.capstring {
ispss = true
break
}
}
if !ispss {
log.Trace("peer doesn't have matching pss capabilities, skipping", "peer", info.Name, "caps", info.Caps)
return true
}
// get the protocol peer from the forwarding peer cache
sendMsg := fmt.Sprintf("MSG TO %x FROM %x VIA %x", to, p.BaseAddr(), sp.Address())
p.fwdPoolMu.RLock()
pp := p.fwdPool[sp.Info().ID]
p.fwdPoolMu.RUnlock()
// attempt to send the message
err := pp.Send(context.TODO(), msg)
if err != nil {
metrics.GetOrRegisterCounter("pss.pp.send.error", nil).Inc(1)
log.Error(err.Error())
return true
}
sent++
log.Trace(fmt.Sprintf("%v: successfully forwarded", sendMsg))
// continue forwarding if:
// - if the peer is end recipient but the full address has not been disclosed
// - if the peer address matches the partial address fully
// - if the peer is in proxbin
if len(msg.To) < addressLength && bytes.Equal(msg.To, sp.Address()[:len(msg.To)]) {
log.Trace(fmt.Sprintf("Pss keep forwarding: Partial address + full partial match"))
return true
} else if isproxbin {
log.Trace(fmt.Sprintf("%x is in proxbin, keep forwarding", common.ToHex(sp.Address())))
return true
}
// at this point we stop forwarding, and the state is as follows:
// - the peer is end recipient and we have full address
// - we are not in proxbin (directed routing)
// - partial addresses don't fully match
return false
})
if sent == 0 {
log.Debug("unable to forward to any peers")
if err := p.enqueue(msg); err != nil {
metrics.GetOrRegisterCounter("pss.forward.enqueue.error", nil).Inc(1)
log.Error(err.Error())
return err
}
}
// cache the message
p.addFwdCache(msg)
return nil
}
/////////////////////////////////////////////////////////////////////
// SECTION: Caching
/////////////////////////////////////////////////////////////////////
// cleanFwdCache is used to periodically remove expired entries from the forward cache
func (p *Pss) cleanFwdCache() {
metrics.GetOrRegisterCounter("pss.cleanfwdcache", nil).Inc(1)
p.fwdCacheMu.Lock()
defer p.fwdCacheMu.Unlock()
for k, v := range p.fwdCache {
if v.expiresAt.Before(time.Now()) {
delete(p.fwdCache, k)
}
}
}
// add a message to the cache
func (p *Pss) addFwdCache(msg *PssMsg) error {
metrics.GetOrRegisterCounter("pss.addfwdcache", nil).Inc(1)
var entry pssCacheEntry
var ok bool
p.fwdCacheMu.Lock()
defer p.fwdCacheMu.Unlock()
digest := p.digest(msg)
if entry, ok = p.fwdCache[digest]; !ok {
entry = pssCacheEntry{}
}
entry.expiresAt = time.Now().Add(p.cacheTTL)
p.fwdCache[digest] = entry
return nil
}
// check if message is in the cache
func (p *Pss) checkFwdCache(msg *PssMsg) bool {
p.fwdCacheMu.Lock()
defer p.fwdCacheMu.Unlock()
digest := p.digest(msg)
entry, ok := p.fwdCache[digest]
if ok {
if entry.expiresAt.After(time.Now()) {
log.Trace("unexpired cache", "digest", fmt.Sprintf("%x", digest))
metrics.GetOrRegisterCounter("pss.checkfwdcache.unexpired", nil).Inc(1)
return true
}
metrics.GetOrRegisterCounter("pss.checkfwdcache.expired", nil).Inc(1)
}
return false
}
// Digest of message
func (p *Pss) digest(msg *PssMsg) pssDigest {
hasher := p.hashPool.Get().(storage.SwarmHash)
defer p.hashPool.Put(hasher)
hasher.Reset()
hasher.Write(msg.serialize())
digest := pssDigest{}
key := hasher.Sum(nil)
copy(digest[:], key[:digestLength])
return digest
}
