Prevent frequent requests with same topics

params/config.go

@@ -8,6 +8,7 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
+	"time"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/crypto"
@@ -315,6 +316,8 @@ type ShhextConfig struct {
 	EnableLastUsedMonitor bool
 	// ConnectionTarget will be used by connection manager. It will ensure that we connected with configured number of servers.
 	ConnectionTarget int
+	// RequestsDelay used to ensure that no similar requests are sent within short periods of time.
+	RequestsDelay time.Duration
 }
 
 // Validate validates the ShhextConfig struct and returns an error if inconsistent values are found

services/shhext/api.go

@@ -80,6 +80,9 @@ type MessagesRequest struct {
 	// Timeout is the time to live of the request specified in seconds.
 	// Default is 10 seconds
 	Timeout time.Duration `json:"timeout"`
+
+	// Force ensures that requests will bypass enforced delay.
+	Force bool `json:"force"`
 }
 
 func (r *MessagesRequest) setDefaults(now time.Time) {
@@ -223,11 +226,17 @@ func (api *PublicAPI) RequestMessages(_ context.Context, r MessagesRequest) (hex
 	if err != nil {
 		return nil, err
 	}
+	hash := envelope.Hash()
+	if !r.Force {
+		err = api.service.requestsRegistry.Register(hash, r.Topics)
+		if err != nil {
+			return nil, err
+		}
+	}
 
 	if err := shh.RequestHistoricMessagesWithTimeout(mailServerNode.ID().Bytes(), envelope, r.Timeout*time.Second); err != nil {
 		return nil, err
 	}
-	hash := envelope.Hash()
 	return hash[:], nil
 }
 

services/shhext/requests.go

@@ -0,0 +1,83 @@
+package shhext
+
+import (
+	"fmt"
+	"hash/fnv"
+	"sync"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common"
+	whisper "github.com/status-im/whisper/whisperv6"
+)
+
+const (
+	// defaultRequestsDelay will be used in RequestsRegistry if no other was provided.
+	defaultRequestsDelay = 3 * time.Second
+)
+
+type requestMeta struct {
+	timestamp time.Time
+	lastUID   common.Hash
+}
+
+// NewRequestsRegistry creates instance of the RequestsRegistry and returns pointer to it.
+func NewRequestsRegistry(delay time.Duration) *RequestsRegistry {
+	return &RequestsRegistry{
+		delay:        delay,
+		uidToTopics:  map[common.Hash]common.Hash{},
+		byTopicsHash: map[common.Hash]requestMeta{},
+	}
+}
+
+// RequestsRegistry keeps map for all requests with timestamp when they were made.
+type RequestsRegistry struct {
+	mu           sync.Mutex
+	delay        time.Duration
+	uidToTopics  map[common.Hash]common.Hash
+	byTopicsHash map[common.Hash]requestMeta
+}
+
+// Register request with given topics. If request with same topics was made in less then configured delay then error
+// will be returned.
+func (r *RequestsRegistry) Register(uid common.Hash, topics []whisper.TopicType) error {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	topicsHash := topicsToHash(topics)
+	if meta, exist := r.byTopicsHash[topicsHash]; exist {
+		if time.Since(meta.timestamp) < r.delay {
+			return fmt.Errorf("another request with the same topics was sent less than %s ago. Please wait for a bit longer, or set `force` to true in request parameters", r.delay)
+		}
+	}
+	newMeta := requestMeta{
+		timestamp: time.Now(),
+		lastUID:   uid,
+	}
+	r.uidToTopics[uid] = topicsHash
+	r.byTopicsHash[topicsHash] = newMeta
+	return nil
+}
+
+// Unregister removes request with given UID from registry.
+func (r *RequestsRegistry) Unregister(uid common.Hash) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	topicsHash, exist := r.uidToTopics[uid]
+	if !exist {
+		return
+	}
+	delete(r.uidToTopics, uid)
+	meta := r.byTopicsHash[topicsHash]
+	// remove topicsHash only if we are trying to unregister last request with this topic.
+	if meta.lastUID == uid {
+		delete(r.byTopicsHash, topicsHash)
+	}
+}
+
+// topicsToHash returns non-cryptographic hash of the topics.
+func topicsToHash(topics []whisper.TopicType) common.Hash {
+	hash := fnv.New32()
+	for i := range topics {
+		_, _ = hash.Write(topics[i][:]) // never returns error per documentation
+	}
+	return common.BytesToHash(hash.Sum(nil))
+}

services/shhext/requests_test.go

@@ -0,0 +1,44 @@
+package shhext
+
+import (
+	"testing"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common"
+	whisper "github.com/status-im/whisper/whisperv6"
+	"github.com/stretchr/testify/require"
+)
+
+func TestRegisterSameRequests(t *testing.T) {
+	registry := NewRequestsRegistry(10 * time.Second)
+	topics := []whisper.TopicType{{1}}
+	require.NoError(t, registry.Register(common.Hash{1}, topics))
+	require.Error(t, registry.Register(common.Hash{2}, topics))
+}
+
+func TestRegisterSameRequestsWithoutDelay(t *testing.T) {
+	registry := NewRequestsRegistry(0)
+	topics := []whisper.TopicType{{1}}
+	require.NoError(t, registry.Register(common.Hash{1}, topics))
+	require.NoError(t, registry.Register(common.Hash{2}, topics))
+}
+
+func TestRegisterDifferentRequests(t *testing.T) {
+	registry := NewRequestsRegistry(10 * time.Second)
+	require.NoError(t, registry.Register(common.Hash{1}, []whisper.TopicType{{1}}))
+	require.NoError(t, registry.Register(common.Hash{2}, []whisper.TopicType{{2}}))
+}
+
+func TestUnregisterReplacedRequest(t *testing.T) {
+	registry := NewRequestsRegistry(0)
+	unreg := common.Hash{1}
+	topics := []whisper.TopicType{{1}}
+	require.NoError(t, registry.Register(unreg, topics))
+	replacement := common.Hash{2}
+	require.NoError(t, registry.Register(replacement, topics))
+	// record should be replaced with common.Hash{2}, so when we will remove unreg it will not affect topics map
+	registry.Unregister(unreg)
+	record, exist := registry.uidToTopics[replacement]
+	require.True(t, exist, "replaced record should exist")
+	require.Equal(t, replacement, registry.byTopicsHash[record].lastUID)
+}

services/shhext/service.go

@@ -44,6 +44,7 @@ type Service struct {
 	w                *whisper.Whisper
 	config           params.ShhextConfig
 	tracker          *tracker
+	requestsRegistry *RequestsRegistry
 	server           *p2p.Server
 	nodeID           *ecdsa.PrivateKey
 	deduplicator     *dedup.Deduplicator
@@ -66,6 +67,11 @@ var _ node.Service = (*Service)(nil)
 func New(w *whisper.Whisper, handler EnvelopeEventsHandler, db *leveldb.DB, config params.ShhextConfig) *Service {
 	cache := mailservers.NewCache(db)
 	ps := mailservers.NewPeerStore(cache)
+	delay := defaultRequestsDelay
+	if config.RequestsDelay != 0 {
+		delay = config.RequestsDelay
+	}
+	requestsRegistry := NewRequestsRegistry(delay)
 	track := &tracker{
 		w:                      w,
 		handler:                handler,
@@ -73,11 +79,13 @@ func New(w *whisper.Whisper, handler EnvelopeEventsHandler, db *leveldb.DB, conf
 		batches:                map[common.Hash]map[common.Hash]struct{}{},
 		mailPeers:              ps,
 		mailServerConfirmation: config.MailServerConfirmations,
+		requestsRegistry:       requestsRegistry,
 	}
 	return &Service{
 		w:                w,
 		config:           config,
 		tracker:          track,
+		requestsRegistry: requestsRegistry,
 		deduplicator:     dedup.NewDeduplicator(w, db),
 		debug:            config.DebugAPIEnabled,
 		dataDir:          config.BackupDisabledDataDir,

services/shhext/service_test.go

@@ -242,6 +242,26 @@ func (s *ShhExtSuite) TestRequestMessagesErrors() {
 	s.Contains(err.Error(), "Query range is invalid: from > to (10 > 5)")
 }
 
+func (s *ShhExtSuite) TestMultipleRequestMessagesWithoutForce() {
+	waitErr := helpers.WaitForPeerAsync(s.nodes[0].Server(), s.nodes[1].Server().Self().String(), p2p.PeerEventTypeAdd, time.Second)
+	s.nodes[0].Server().AddPeer(s.nodes[1].Server().Self())
+	s.Require().NoError(<-waitErr)
+	client, err := s.nodes[0].Attach()
+	s.NoError(err)
+	s.NoError(client.Call(nil, "shhext_requestMessages", MessagesRequest{
+		MailServerPeer: s.nodes[1].Server().Self().String(),
+		Topics:         []whisper.TopicType{{1}},
+	}))
+	s.EqualError(client.Call(nil, "shhext_requestMessages", MessagesRequest{
+		MailServerPeer: s.nodes[1].Server().Self().String(),
+		Topics:         []whisper.TopicType{{1}},
+	}), "another request with the same topics was sent less than 3s ago. Please wait for a bit longer, or set `force` to true in request parameters")
+	s.NoError(client.Call(nil, "shhext_requestMessages", MessagesRequest{
+		MailServerPeer: s.nodes[1].Server().Self().String(),
+		Topics:         []whisper.TopicType{{2}},
+	}))
+}
+
 func (s *ShhExtSuite) TestRequestMessagesSuccess() {
 	var err error
 
@@ -301,6 +321,7 @@ func (s *ShhExtSuite) TestRequestMessagesSuccess() {
 	hash, err = api.RequestMessages(context.TODO(), MessagesRequest{
 		MailServerPeer: mailNode.Server().Self().String(),
 		SymKeyID:       symKeyID,
+		Force:          true,
 	})
 	s.Require().NoError(err)
 	s.Require().NotNil(hash)
@@ -309,6 +330,7 @@ func (s *ShhExtSuite) TestRequestMessagesSuccess() {
 	// a public key extracted from MailServerPeer will be used.
 	hash, err = api.RequestMessages(context.TODO(), MessagesRequest{
 		MailServerPeer: mailNode.Server().Self().String(),
+		Force:          true,
 	})
 	s.Require().NoError(err)
 	s.Require().NotNil(hash)

services/shhext/tracker.go

@@ -37,6 +37,8 @@ type tracker struct {
 
 	mailPeers *mailservers.PeerStore
 
+	requestsRegistry *RequestsRegistry
+
 	wg   sync.WaitGroup
 	quit chan struct{}
 }
@@ -194,7 +196,7 @@ func (t *tracker) handleRequestSent(event whisper.EnvelopeEvent) {
 func (t *tracker) handleEventMailServerRequestCompleted(event whisper.EnvelopeEvent) {
 	t.mu.Lock()
 	defer t.mu.Unlock()
-
+	t.requestsRegistry.Unregister(event.Hash)
 	state, ok := t.cache[event.Hash]
 	if !ok || state != MailServerRequestSent {
 		return
@@ -211,7 +213,7 @@ func (t *tracker) handleEventMailServerRequestCompleted(event whisper.EnvelopeEv
 func (t *tracker) handleEventMailServerRequestExpired(event whisper.EnvelopeEvent) {
 	t.mu.Lock()
 	defer t.mu.Unlock()
-
+	t.requestsRegistry.Unregister(event.Hash)
 	state, ok := t.cache[event.Hash]
 	if !ok || state != MailServerRequestSent {
 		return

services/shhext/tracker_test.go

@@ -36,6 +36,7 @@ func (s *TrackerSuite) SetupTest() {
 		cache:            map[common.Hash]EnvelopeState{},
 		batches:          map[common.Hash]map[common.Hash]struct{}{},
 		mailPeers:        mailservers.NewPeerStore(mailservers.NewCache(db)),
+		requestsRegistry: NewRequestsRegistry(0),
 	}
 }
 

vendor/github.com/status-im/whisper/whisperv6/message.go

@@ -75,6 +75,7 @@ type ReceivedMessage struct {
 
 	SymKeyHash   common.Hash // The Keccak256Hash of the key
 	EnvelopeHash common.Hash // Message envelope hash to act as a unique id
+	History      bool
 }
 
 func isMessageSigned(flags byte) bool {