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mailserver.go
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mailserver.go
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// Copyright 2017 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 mailserver
import (
"encoding/binary"
"errors"
"fmt"
"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/metrics"
"github.com/ethereum/go-ethereum/rlp"
"github.com/status-im/status-go/db"
"github.com/status-im/status-go/params"
whisper "github.com/status-im/whisper/whisperv6"
"github.com/syndtr/goleveldb/leveldb"
"github.com/syndtr/goleveldb/leveldb/iterator"
"github.com/syndtr/goleveldb/leveldb/opt"
"github.com/syndtr/goleveldb/leveldb/util"
)
const (
maxQueryRange = 24 * time.Hour
noLimits = 0
)
var (
errDirectoryNotProvided = errors.New("data directory not provided")
errDecryptionMethodNotProvided = errors.New("decryption method is not provided")
// By default go-ethereum/metrics creates dummy metrics that don't register anything.
// Real metrics are collected only if -metrics flag is set
requestProcessTimer = metrics.NewRegisteredTimer("mailserver/requestProcessTime", nil)
requestsMeter = metrics.NewRegisteredMeter("mailserver/requests", nil)
requestErrorsCounter = metrics.NewRegisteredCounter("mailserver/requestErrors", nil)
sentEnvelopesMeter = metrics.NewRegisteredMeter("mailserver/sentEnvelopes", nil)
sentEnvelopesSizeMeter = metrics.NewRegisteredMeter("mailserver/sentEnvelopesSize", nil)
archivedMeter = metrics.NewRegisteredMeter("mailserver/archivedEnvelopes", nil)
archivedSizeMeter = metrics.NewRegisteredMeter("mailserver/archivedEnvelopesSize", nil)
archivedErrorsCounter = metrics.NewRegisteredCounter("mailserver/archiveErrors", nil)
)
const (
timestampLength = 4
dbKeyLength = common.HashLength + timestampLength
requestLimitLength = 4
requestTimeRangeLength = timestampLength * 2
)
type cursorType []byte
// dbImpl is an interface introduced to be able to test some unexpected
// panics from leveldb that are difficult to reproduce.
// normally the db implementation is leveldb.DB, but in TestMailServerDBPanicSuite
// we use panicDB to test panics from the db.
// more info about the panic errors:
// https://github.com/syndtr/goleveldb/issues/224
type dbImpl interface {
Close() error
Write(*leveldb.Batch, *opt.WriteOptions) error
Put([]byte, []byte, *opt.WriteOptions) error
Get([]byte, *opt.ReadOptions) ([]byte, error)
NewIterator(*util.Range, *opt.ReadOptions) iterator.Iterator
}
// WMailServer whisper mailserver.
type WMailServer struct {
db dbImpl
w *whisper.Whisper
pow float64
symFilter *whisper.Filter
asymFilter *whisper.Filter
muLimiter sync.RWMutex
limiter *limiter
tick *ticker
}
// DBKey key to be stored on db.
type DBKey struct {
timestamp uint32
hash common.Hash
raw []byte
}
// NewDbKey creates a new DBKey with the given values.
func NewDbKey(t uint32, h common.Hash) *DBKey {
var k DBKey
k.timestamp = t
k.hash = h
k.raw = make([]byte, dbKeyLength)
binary.BigEndian.PutUint32(k.raw, k.timestamp)
copy(k.raw[4:], k.hash[:])
return &k
}
// Init initializes mailServer.
func (s *WMailServer) Init(shh *whisper.Whisper, config *params.WhisperConfig) error {
var err error
if len(config.DataDir) == 0 {
return errDirectoryNotProvided
}
if len(config.MailServerPassword) == 0 && len(config.MailServerAsymKey) == 0 {
return errDecryptionMethodNotProvided
}
s.w = shh
s.pow = config.MinimumPoW
if err := s.setupRequestMessageDecryptor(config); err != nil {
return err
}
s.setupLimiter(time.Duration(config.MailServerRateLimit) * time.Second)
// Open database in the last step in order not to init with error
// and leave the database open by accident.
database, err := db.Open(config.DataDir, nil)
if err != nil {
return fmt.Errorf("open DB: %s", err)
}
s.db = database
return nil
}
// setupLimiter in case limit is bigger than 0 it will setup an automated
// limit db cleanup.
func (s *WMailServer) setupLimiter(limit time.Duration) {
if limit > 0 {
s.limiter = newLimiter(limit)
s.setupMailServerCleanup(limit)
}
}
// setupRequestMessageDecryptor setup a Whisper filter to decrypt
// incoming Whisper requests.
func (s *WMailServer) setupRequestMessageDecryptor(config *params.WhisperConfig) error {
s.symFilter = nil
s.asymFilter = nil
if config.MailServerPassword != "" {
keyID, err := s.w.AddSymKeyFromPassword(config.MailServerPassword)
if err != nil {
return fmt.Errorf("create symmetric key: %v", err)
}
symKey, err := s.w.GetSymKey(keyID)
if err != nil {
return fmt.Errorf("save symmetric key: %v", err)
}
s.symFilter = &whisper.Filter{KeySym: symKey}
}
if config.MailServerAsymKey != "" {
keyAsym, err := crypto.HexToECDSA(config.MailServerAsymKey)
if err != nil {
return err
}
s.asymFilter = &whisper.Filter{KeyAsym: keyAsym}
}
return nil
}
// setupMailServerCleanup periodically runs an expired entries deleteion for
// stored limits.
func (s *WMailServer) setupMailServerCleanup(period time.Duration) {
if s.tick == nil {
s.tick = &ticker{}
}
go s.tick.run(period, s.limiter.deleteExpired)
}
// Close the mailserver and its associated db connection.
func (s *WMailServer) Close() {
if s.db != nil {
if err := s.db.Close(); err != nil {
log.Error(fmt.Sprintf("s.db.Close failed: %s", err))
}
}
if s.tick != nil {
s.tick.stop()
}
}
func recoverLevelDBPanics(calleMethodName string) {
// Recover from possible goleveldb panics
if r := recover(); r != nil {
if errString, ok := r.(string); ok {
log.Error(fmt.Sprintf("recovered from panic in %s: %s", calleMethodName, errString))
}
}
}
// Archive a whisper envelope.
func (s *WMailServer) Archive(env *whisper.Envelope) {
defer recoverLevelDBPanics("Archive")
key := NewDbKey(env.Expiry-env.TTL, env.Hash())
rawEnvelope, err := rlp.EncodeToBytes(env)
if err != nil {
log.Error(fmt.Sprintf("rlp.EncodeToBytes failed: %s", err))
archivedErrorsCounter.Inc(1)
} else {
if err = s.db.Put(key.raw, rawEnvelope, nil); err != nil {
log.Error(fmt.Sprintf("Writing to DB failed: %s", err))
archivedErrorsCounter.Inc(1)
}
archivedMeter.Mark(1)
archivedSizeMeter.Mark(int64(whisper.EnvelopeHeaderLength + len(env.Data)))
}
}
// DeliverMail sends mail to specified whisper peer.
func (s *WMailServer) DeliverMail(peer *whisper.Peer, request *whisper.Envelope) {
log.Info("Delivering mail", "peer", peer.ID)
requestsMeter.Mark(1)
if peer == nil {
requestErrorsCounter.Inc(1)
log.Error("Whisper peer is nil")
return
}
if s.exceedsPeerRequests(peer.ID()) {
requestErrorsCounter.Inc(1)
return
}
defer recoverLevelDBPanics("DeliverMail")
if ok, lower, upper, bloom, limit, cursor := s.validateRequest(peer.ID(), request); ok {
_, lastEnvelopeHash, nextPageCursor, err := s.processRequest(peer, lower, upper, bloom, limit, cursor)
if err != nil {
log.Error(fmt.Sprintf("error in DeliverMail: %s", err))
return
}
if err := s.sendHistoricMessageResponse(peer, request, lastEnvelopeHash, nextPageCursor); err != nil {
log.Error(fmt.Sprintf("SendHistoricMessageResponse error: %s", err))
}
}
}
// exceedsPeerRequests in case limit its been setup on the current server and limit
// allows the query, it will store/update new query time for the current peer.
func (s *WMailServer) exceedsPeerRequests(peer []byte) bool {
s.muLimiter.RLock()
defer s.muLimiter.RUnlock()
if s.limiter != nil {
peerID := string(peer)
if !s.limiter.isAllowed(peerID) {
log.Info("peerID exceeded the number of requests per second")
return true
}
s.limiter.add(peerID)
}
return false
}
// processRequest processes the current request and re-sends all stored messages
// accomplishing lower and upper limits. The limit parameter determines the maximum number of
// messages to be sent back for the current request.
// The cursor parameter is used for pagination.
// After sending all the messages, a message of type p2pRequestCompleteCode is sent by the mailserver to
// the peer.
func (s *WMailServer) processRequest(peer *whisper.Peer, lower, upper uint32, bloom []byte, limit uint32, cursor cursorType) (ret []*whisper.Envelope, lastEnvelopeHash common.Hash, nextPageCursor cursorType, err error) {
// Recover from possible goleveldb panics
defer func() {
if r := recover(); r != nil {
err = fmt.Errorf("recovered from panic in processRequest: %v", r)
}
}()
var (
sentEnvelopes uint32
sentEnvelopesSize int64
zero common.Hash
ku []byte
kl []byte
)
kl = NewDbKey(lower, zero).raw
if cursor != nil {
ku = cursor
} else {
ku = NewDbKey(upper+1, zero).raw
}
i := s.db.NewIterator(&util.Range{Start: kl, Limit: ku}, nil)
i.Seek(ku)
defer i.Release()
start := time.Now()
for i.Prev() {
var envelope whisper.Envelope
decodeErr := rlp.DecodeBytes(i.Value(), &envelope)
if decodeErr != nil {
log.Error(fmt.Sprintf("RLP decoding failed: %s", decodeErr))
continue
}
if whisper.BloomFilterMatch(bloom, envelope.Bloom()) {
if peer == nil {
// used for test purposes
ret = append(ret, &envelope)
} else {
err = s.w.SendP2PDirect(peer, &envelope)
if err != nil {
log.Error(fmt.Sprintf("Failed to send direct message to peer: %s", err))
return
}
lastEnvelopeHash = envelope.Hash()
}
sentEnvelopes++
sentEnvelopesSize += whisper.EnvelopeHeaderLength + int64(len(envelope.Data))
if limit != noLimits && sentEnvelopes == limit {
nextPageCursor = i.Key()
break
}
}
}
requestProcessTimer.UpdateSince(start)
sentEnvelopesMeter.Mark(int64(sentEnvelopes))
sentEnvelopesSizeMeter.Mark(sentEnvelopesSize)
err = i.Error()
if err != nil {
log.Error(fmt.Sprintf("Level DB iterator error: %s", err))
}
return
}
func (s *WMailServer) sendHistoricMessageResponse(peer *whisper.Peer, request *whisper.Envelope, lastEnvelopeHash common.Hash, cursor cursorType) error {
requestID := request.Hash()
payload := append(requestID[:], lastEnvelopeHash[:]...)
payload = append(payload, cursor...)
return s.w.SendHistoricMessageResponse(peer, payload)
}
// openEnvelope tries to decrypt an envelope, first based on asymetric key (if
// provided) and second on the symetric key (if provided)
func (s *WMailServer) openEnvelope(request *whisper.Envelope) *whisper.ReceivedMessage {
if s.asymFilter != nil {
if d := request.Open(s.asymFilter); d != nil {
return d
}
}
if s.symFilter != nil {
if d := request.Open(s.symFilter); d != nil {
return d
}
}
return nil
}
// validateRequest runs different validations on the current request.
func (s *WMailServer) validateRequest(peerID []byte, request *whisper.Envelope) (bool, uint32, uint32, []byte, uint32, cursorType) {
if s.pow > 0.0 && request.PoW() < s.pow {
return false, 0, 0, nil, 0, nil
}
decrypted := s.openEnvelope(request)
if decrypted == nil {
log.Warn("Failed to decrypt p2p request")
return false, 0, 0, nil, 0, nil
}
if err := s.checkMsgSignature(decrypted, peerID); err != nil {
log.Warn(err.Error())
return false, 0, 0, nil, 0, nil
}
bloom, err := s.bloomFromReceivedMessage(decrypted)
if err != nil {
log.Warn(err.Error())
return false, 0, 0, nil, 0, nil
}
lower := binary.BigEndian.Uint32(decrypted.Payload[:4])
upper := binary.BigEndian.Uint32(decrypted.Payload[4:8])
if upper < lower {
log.Error(fmt.Sprintf("Query range is invalid: from > to (%d > %d)", lower, upper))
return false, 0, 0, nil, 0, nil
}
lowerTime := time.Unix(int64(lower), 0)
upperTime := time.Unix(int64(upper), 0)
if upperTime.Sub(lowerTime) > maxQueryRange {
log.Warn(fmt.Sprintf("Query range too big for peer %s", string(peerID)))
return false, 0, 0, nil, 0, nil
}
var limit uint32
if len(decrypted.Payload) >= requestTimeRangeLength+whisper.BloomFilterSize+requestLimitLength {
limit = binary.BigEndian.Uint32(decrypted.Payload[requestTimeRangeLength+whisper.BloomFilterSize:])
}
var cursor cursorType
if len(decrypted.Payload) == requestTimeRangeLength+whisper.BloomFilterSize+requestLimitLength+dbKeyLength {
cursor = decrypted.Payload[requestTimeRangeLength+whisper.BloomFilterSize+requestLimitLength:]
}
return true, lower, upper, bloom, limit, cursor
}
// checkMsgSignature returns an error in case the message is not correcly signed
func (s *WMailServer) checkMsgSignature(msg *whisper.ReceivedMessage, id []byte) error {
src := crypto.FromECDSAPub(msg.Src)
if len(src)-len(id) == 1 {
src = src[1:]
}
// if you want to check the signature, you can do it here. e.g.:
// if !bytes.Equal(peerID, src) {
if src == nil {
return errors.New("Wrong signature of p2p request")
}
return nil
}
// bloomFromReceivedMessage gor a given whisper.ReceivedMessage it extracts the
// used bloom filter
func (s *WMailServer) bloomFromReceivedMessage(msg *whisper.ReceivedMessage) ([]byte, error) {
payloadSize := len(msg.Payload)
if payloadSize < 8 {
return nil, errors.New("Undersized p2p request")
} else if payloadSize == 8 {
return whisper.MakeFullNodeBloom(), nil
} else if payloadSize < 8+whisper.BloomFilterSize {
return nil, errors.New("Undersized bloom filter in p2p request")
}
return msg.Payload[8 : 8+whisper.BloomFilterSize], nil
}