Split datasync messages in batches

When sending messages in quick succession, it might be that multiple
messages are batched together in datasync, resulting in a single large
payload.
This commit changes the behavior so that we can pass a max-message-size
and we split the message in batches before sending.

A more elegant way would be to split at the transport layer (i.e
waku/whisper), but that would be incompatible with older client.

We can still do that eventually to support larger messages.

VERSION

@@ -1 +1 @@
-0.63.1
+0.63.2

eth-node/bridge/geth/waku.go

@@ -38,6 +38,11 @@ func (w *gethWakuWrapper) MinPow() float64 {
 	return w.waku.MinPow()
 }
 
+// MaxMessageSize returns the MaxMessageSize set
+func (w *gethWakuWrapper) MaxMessageSize() uint32 {
+	return w.waku.MaxMessageSize()
+}
+
 // BloomFilter returns the aggregated bloom filter for all the topics of interest.
 // The nodes are required to send only messages that match the advertised bloom filter.
 // If a message does not match the bloom, it will tantamount to spam, and the peer will

eth-node/bridge/geth/whisper.go

@@ -37,6 +37,11 @@ func (w *gethWhisperWrapper) MinPow() float64 {
 	return w.whisper.MinPow()
 }
 
+// MaxMessageSize returns the MaxMessageSize set
+func (w *gethWhisperWrapper) MaxMessageSize() uint32 {
+	return w.whisper.MaxMessageSize()
+}
+
 // BloomFilter returns the aggregated bloom filter for all the topics of interest.
 // The nodes are required to send only messages that match the advertised bloom filter.
 // If a message does not match the bloom, it will tantamount to spam, and the peer will

eth-node/types/waku.go

@@ -35,6 +35,7 @@ type Waku interface {
 	AddSymKeyFromPassword(password string) (string, error)
 	DeleteSymKey(id string) bool
 	GetSymKey(id string) ([]byte, error)
+	MaxMessageSize() uint32
 
 	Subscribe(opts *SubscriptionOptions) (string, error)
 	GetFilter(id string) Filter

eth-node/types/whisper.go

@@ -21,6 +21,7 @@ type Whisper interface {
 	SetTimeSource(timesource func() time.Time)
 	// GetCurrentTime returns current time.
 	GetCurrentTime() time.Time
+	MaxMessageSize() uint32
 
 	// GetPrivateKey retrieves the private key of the specified identity.
 	GetPrivateKey(id string) (*ecdsa.PrivateKey, error)

protocol/common/message_processor.go

@@ -103,7 +103,11 @@ func NewMessageProcessor(
 	// but actual encrypt and send calls are postponed.
 	// sendDataSync is responsible for encrypting and sending postponed messages.
 	if features.Datasync {
-		ds.Init(p.sendDataSync)
+		// We set the max message size to 3/4 of the allowed message size, to leave
+		// room for encryption.
+		// Messages will be tried to send in any case, even if they exceed this
+		// value
+		ds.Init(p.sendDataSync, transport.MaxMessageSize()/4*3, logger)
 		ds.Start(300 * time.Millisecond)
 	}
 

protocol/datasync/transport.go

@@ -9,15 +9,24 @@ import (
 	"github.com/vacp2p/mvds/protobuf"
 	"github.com/vacp2p/mvds/state"
 	"github.com/vacp2p/mvds/transport"
+	"go.uber.org/zap"
 
 	datasyncpeer "github.com/status-im/status-go/protocol/datasync/peer"
 )
 
 var errNotInitialized = errors.New("Datasync transport not initialized")
 
+// payloadTagSize is the tag size for the protobuf.Payload message which is number of fields * 2 bytes
+var payloadTagSize = 14
+
+// timestampPayloadSize is the maximum size in bytes for the timestamp field (uint64)
+var timestampPayloadSize = 10
+
 type NodeTransport struct {
-	packets  chan transport.Packet
-	dispatch func(context.Context, *ecdsa.PublicKey, []byte, *protobuf.Payload) error
+	packets        chan transport.Packet
+	logger         *zap.Logger
+	maxMessageSize uint32
+	dispatch       func(context.Context, *ecdsa.PublicKey, []byte, *protobuf.Payload) error
 }
 
 func NewNodeTransport() *NodeTransport {
@@ -26,8 +35,10 @@ func NewNodeTransport() *NodeTransport {
 	}
 }
 
-func (t *NodeTransport) Init(dispatch func(context.Context, *ecdsa.PublicKey, []byte, *protobuf.Payload) error) {
+func (t *NodeTransport) Init(dispatch func(context.Context, *ecdsa.PublicKey, []byte, *protobuf.Payload) error, maxMessageSize uint32, logger *zap.Logger) {
 	t.dispatch = dispatch
+	t.maxMessageSize = maxMessageSize
+	t.logger = logger
 }
 
 func (t *NodeTransport) AddPacket(p transport.Packet) {
@@ -39,21 +50,100 @@ func (t *NodeTransport) Watch() transport.Packet {
 }
 
 func (t *NodeTransport) Send(_ state.PeerID, peer state.PeerID, payload protobuf.Payload) error {
+	var lastError error
 	if t.dispatch == nil {
 		return errNotInitialized
 	}
 
-	data, err := proto.Marshal(&payload)
-	if err != nil {
-		return err
+	payloads := splitPayloadInBatches(&payload, int(t.maxMessageSize))
+	for _, payload := range payloads {
+
+		data, err := proto.Marshal(payload)
+		if err != nil {
+			return err
+		}
+
+		publicKey, err := datasyncpeer.IDToPublicKey(peer)
+		if err != nil {
+			return err
+		}
+		err = t.dispatch(context.Background(), publicKey, data, payload)
+		if err != nil {
+			lastError = err
+			t.logger.Error("failed to send message", zap.Error(err))
+			continue
+		}
+	}
+	return lastError
+}
+
+func splitPayloadInBatches(payload *protobuf.Payload, maxSizeBytes int) []*protobuf.Payload {
+	newPayload := &protobuf.Payload{}
+	var response []*protobuf.Payload
+	currentSize := payloadTagSize
+
+	// this is not going to be 100% accurate, but should be fine in most cases, faster
+	// than using proto.Size
+	for _, ack := range payload.Acks {
+		if len(ack)+currentSize+1 > maxSizeBytes {
+			// We check if it's valid as it might be that the initial message
+			// is too big, in this case we still batch it
+			if newPayload.IsValid() {
+				response = append(response, newPayload)
+			}
+			newPayload = &protobuf.Payload{Acks: [][]byte{ack}}
+			currentSize = len(ack) + payloadTagSize + 1
+		} else {
+			newPayload.Acks = append(newPayload.Acks, ack)
+			currentSize += len(ack)
+		}
 	}
 
-	publicKey, err := datasyncpeer.IDToPublicKey(peer)
-	if err != nil {
-		return err
+	for _, offer := range payload.Offers {
+		if len(offer)+currentSize+1 > maxSizeBytes {
+			if newPayload.IsValid() {
+				response = append(response, newPayload)
+			}
+			newPayload = &protobuf.Payload{Offers: [][]byte{offer}}
+			currentSize = len(offer) + payloadTagSize + 1
+		} else {
+			newPayload.Offers = append(newPayload.Offers, offer)
+			currentSize += len(offer)
+		}
 	}
 
-	return t.dispatch(context.TODO(), publicKey, data, &payload)
+	for _, request := range payload.Requests {
+		if len(request)+currentSize+1 > maxSizeBytes {
+			if newPayload.IsValid() {
+				response = append(response, newPayload)
+			}
+			newPayload = &protobuf.Payload{Requests: [][]byte{request}}
+			currentSize = len(request) + payloadTagSize + 1
+		} else {
+			newPayload.Requests = append(newPayload.Requests, request)
+			currentSize += len(request)
+		}
+	}
+
+	for _, message := range payload.Messages {
+		// We add the body size, the length field for payload, the length field for group id,
+		// the length of timestamp, body and groupid
+		if currentSize+1+1+timestampPayloadSize+len(message.Body)+len(message.GroupId) > maxSizeBytes {
+			if newPayload.IsValid() {
+				response = append(response, newPayload)
+			}
+			newPayload = &protobuf.Payload{Messages: []*protobuf.Message{message}}
+			currentSize = timestampPayloadSize + len(message.Body) + len(message.GroupId) + payloadTagSize + 1 + 1
+		} else {
+			newPayload.Messages = append(newPayload.Messages, message)
+			currentSize += len(message.Body) + len(message.GroupId) + timestampPayloadSize
+		}
+	}
+
+	if newPayload.IsValid() {
+		response = append(response, newPayload)
+	}
+	return response
 }
 
 // CalculateSendTime calculates the next epoch

protocol/datasync/transport_test.go

@@ -0,0 +1,45 @@
+package datasync
+
+import (
+	"testing"
+
+	"github.com/vacp2p/mvds/protobuf"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestSplitPayloadInBatches(t *testing.T) {
+	payload := &protobuf.Payload{Acks: [][]byte{{0x1}}}
+
+	response := splitPayloadInBatches(payload, 100)
+	require.NotNil(t, response)
+	require.Len(t, response, 1)
+
+	payload = &protobuf.Payload{Acks: [][]byte{{0x1}, {0x2}, {0x3}, {0x4}}}
+	// 1 is the maximum size of the actual ack, + the tag size + 1, the length of the field
+	response = splitPayloadInBatches(payload, 1+payloadTagSize+1)
+	require.NotNil(t, response)
+	require.Len(t, response, 4)
+
+	payload = &protobuf.Payload{Offers: [][]byte{{0x1}, {0x2}, {0x3}, {0x4}}}
+	response = splitPayloadInBatches(payload, 1+payloadTagSize+1)
+	require.NotNil(t, response)
+	require.Len(t, response, 4)
+
+	payload = &protobuf.Payload{Requests: [][]byte{{0x1}, {0x2}, {0x3}, {0x4}}}
+	response = splitPayloadInBatches(payload, 1+payloadTagSize+1)
+	require.NotNil(t, response)
+	require.Len(t, response, 4)
+
+	payload = &protobuf.Payload{Messages: []*protobuf.Message{
+		{GroupId: []byte{0x1}, Timestamp: 1, Body: []byte{0x1}},
+		{GroupId: []byte{0x2}, Timestamp: 1, Body: []byte{0x2}},
+		{GroupId: []byte{0x3}, Timestamp: 1, Body: []byte{0x3}},
+		{GroupId: []byte{0x4}, Timestamp: 1, Body: []byte{0x4}},
+	},
+	}
+	// 1 for the size of Messages + 2 for the sizes of the repeated MessageFields fields + 10 for the worst size of timestamps + 1 for the size of the body + 1 for the size of group id
+	response = splitPayloadInBatches(payload, 1+payloadTagSize+2+timestampPayloadSize+1+1)
+	require.NotNil(t, response)
+	require.Len(t, response, 4)
+}

protocol/transport/transport.go

@@ -17,6 +17,7 @@ type Transport interface {
 	JoinPublic(chatID string) error
 	LeavePublic(chatID string) error
 	GetCurrentTime() uint64
+	MaxMessageSize() uint32
 
 	SendPublic(ctx context.Context, newMessage *types.NewMessage, chatName string) ([]byte, error)
 	SendPrivateWithSharedSecret(ctx context.Context, newMessage *types.NewMessage, publicKey *ecdsa.PublicKey, secret []byte) ([]byte, error)

protocol/transport/waku/waku_service.go

@@ -315,6 +315,10 @@ func (a *Transport) GetCurrentTime() uint64 {
 	return uint64(a.waku.GetCurrentTime().UnixNano() / int64(time.Millisecond))
 }
 
+func (a *Transport) MaxMessageSize() uint32 {
+	return a.waku.MaxMessageSize()
+}
+
 func (a *Transport) Stop() error {
 	if a.envelopesMonitor != nil {
 		a.envelopesMonitor.Stop()

protocol/transport/whisper/whisper_service.go

@@ -366,6 +366,10 @@ func (a *Transport) GetCurrentTime() uint64 {
 	return uint64(a.shh.GetCurrentTime().UnixNano() / int64(time.Millisecond))
 }
 
+func (a *Transport) MaxMessageSize() uint32 {
+	return a.shh.MaxMessageSize()
+}
+
 func (a *Transport) Stop() error {
 	if a.envelopesMonitor != nil {
 		a.envelopesMonitor.Stop()