Avoid using peers returning empty responses, not sending skeleton req…

…uests (erigontech#6281)

Co-authored-by: Alexey Sharp <alexeysharp@Alexeys-iMac.local>

cmd/sentry/sentry/sentry_grpc_server.go

@@ -55,6 +55,7 @@ type PeerInfo struct {
 	peer          *p2p.Peer
 	lock          sync.RWMutex
 	deadlines     []time.Time // Request deadlines
+	uselessTill   time.Time
 	latestDealine time.Time
 	height        uint64
 	rw            p2p.MsgReadWriter
@@ -151,6 +152,12 @@ func (pi *PeerInfo) AddDeadline(deadline time.Time) {
 	pi.latestDealine = deadline
 }
 
+func (pi *PeerInfo) UselessTill(deadline time.Time) {
+	pi.lock.Lock()
+	defer pi.lock.Unlock()
+	pi.uselessTill = deadline
+}
+
 func (pi *PeerInfo) Height() uint64 {
 	return atomic.LoadUint64(&pi.height)
 }
@@ -184,6 +191,12 @@ func (pi *PeerInfo) ClearDeadlines(now time.Time, givePermit bool) int {
 	return len(pi.deadlines)
 }
 
+func (pi *PeerInfo) IsUseless(now time.Time) bool {
+	pi.lock.RLock()
+	defer pi.lock.RUnlock()
+	return now.Before(pi.uselessTill)
+}
+
 func (pi *PeerInfo) LatestDeadline() time.Time {
 	pi.lock.RLock()
 	defer pi.lock.RUnlock()
@@ -736,6 +749,15 @@ func (ss *GrpcServer) PeerMinBlock(_ context.Context, req *proto_sentry.PeerMinB
 	return &emptypb.Empty{}, nil
 }
 
+func (ss *GrpcServer) PeerUseless(_ context.Context, req *proto_sentry.PeerUselessRequest) (*emptypb.Empty, error) {
+	peerID := ConvertH512ToPeerID(req.PeerId)
+	peerInfo := ss.getPeer(peerID)
+	if peerInfo != nil {
+		peerInfo.UselessTill(time.Now().Add(10 * time.Minute))
+	}
+	return &emptypb.Empty{}, nil
+}
+
 func (ss *GrpcServer) findBestPeersWithPermit(peerCount int) []*PeerInfo {
 	// Choose peer(s) that we can send this request to, with maximum number of permits
 	now := time.Now()
@@ -746,7 +768,7 @@ func (ss *GrpcServer) findBestPeersWithPermit(peerCount int) []*PeerInfo {
 		deadlines := peerInfo.ClearDeadlines(now, false /* givePermit */)
 		height := peerInfo.Height()
 		//fmt.Printf("%d deadlines for peer %s\n", deadlines, peerID)
-		if deadlines < maxPermitsPerPeer {
+		if deadlines < maxPermitsPerPeer && !peerInfo.IsUseless(now) {
 			heap.Push(&byMinBlock, PeerRef{pi: peerInfo, height: height})
 			if byMinBlock.Len() > peerCount {
 				// Remove the worst peer
@@ -782,7 +804,7 @@ func (ss *GrpcServer) findPeerByMinBlock(minBlock uint64) (*PeerInfo, bool) {
 		if peerInfo.Height() >= minBlock {
 			deadlines := peerInfo.ClearDeadlines(now, false /* givePermit */)
 			//fmt.Printf("%d deadlines for peer %s\n", deadlines, peerID)
-			if deadlines < maxPermitsPerPeer {
+			if deadlines < maxPermitsPerPeer && !peerInfo.IsUseless(now) {
 				permits := maxPermitsPerPeer - deadlines
 				if permits > maxPermits {
 					maxPermits = permits

cmd/sentry/sentry/sentry_multi_client.go

@@ -390,6 +390,16 @@ func (cs *MultiClient) blockHeaders66(ctx context.Context, in *proto_sentry.Inbo
 }
 
 func (cs *MultiClient) blockHeaders(ctx context.Context, pkt eth.BlockHeadersPacket, rlpStream *rlp.Stream, peerID *proto_types.H512, sentry direct.SentryClient) error {
+	if len(pkt) == 0 {
+		outreq := proto_sentry.PeerUselessRequest{
+			PeerId: peerID,
+		}
+		if _, err := sentry.PeerUseless(ctx, &outreq, &grpc.EmptyCallOption{}); err != nil {
+			return fmt.Errorf("sending peer useless request: %v", err)
+		}
+		// No point processing empty response
+		return nil
+	}
 	// Stream is at the BlockHeadersPacket, which is list of headers
 	if _, err := rlpStream.List(); err != nil {
 		return fmt.Errorf("decode 2 BlockHeadersPacket66: %w", err)

go.mod

@@ -3,7 +3,7 @@ module github.com/ledgerwatch/erigon
 go 1.18
 
 require (
-	github.com/ledgerwatch/erigon-lib v0.0.0-20221211145319-874c497dda90
+	github.com/ledgerwatch/erigon-lib v0.0.0-20221211222033-d70b55bc1a66
 	github.com/ledgerwatch/erigon-snapshot v1.1.1-0.20221117232719-cf68648bf146
 	github.com/ledgerwatch/log/v3 v3.6.0
 	github.com/ledgerwatch/secp256k1 v1.0.0

go.sum

@@ -561,8 +561,8 @@ github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/kylelemons/godebug v0.0.0-20170224010052-a616ab194758 h1:0D5M2HQSGD3PYPwICLl+/9oulQauOuETfgFvhBDffs0=
 github.com/leanovate/gopter v0.2.9 h1:fQjYxZaynp97ozCzfOyOuAGOU4aU/z37zf/tOujFk7c=
 github.com/leanovate/gopter v0.2.9/go.mod h1:U2L/78B+KVFIx2VmW6onHJQzXtFb+p5y3y2Sh+Jxxv8=
-github.com/ledgerwatch/erigon-lib v0.0.0-20221211145319-874c497dda90 h1:ZsCnxEiUWDgp9ed/TeAnF15nVha4TRiL/1RGRecgs/c=
-github.com/ledgerwatch/erigon-lib v0.0.0-20221211145319-874c497dda90/go.mod h1:Cy/yMqN6ufAXayVYLEIKnRoYz25PK9Uxmp1yil+wA/A=
+github.com/ledgerwatch/erigon-lib v0.0.0-20221211222033-d70b55bc1a66 h1:6BpdJ+kx5pAKkVnET5jPTvbP9ymooENJ4k2WYW2LzTY=
+github.com/ledgerwatch/erigon-lib v0.0.0-20221211222033-d70b55bc1a66/go.mod h1:JmIvswKJVoUFNWHzMdszyBdTxboIM4dVs0u5dE6YZmI=
 github.com/ledgerwatch/erigon-snapshot v1.1.1-0.20221117232719-cf68648bf146 h1:BBoJuTSC1Z41wvz26l+HBJCXEBrPh3LXjkJd4CT6n1E=
 github.com/ledgerwatch/erigon-snapshot v1.1.1-0.20221117232719-cf68648bf146/go.mod h1:3AuPxZc85jkehh/HA9h8gabv5MSi3kb/ddtzBsTVJFo=
 github.com/ledgerwatch/log/v3 v3.6.0 h1:JBUSK1epPyutUrz7KYDTcJtQLEHnehECRpKbM1ugy5M=

turbo/stages/headerdownload/header_algos.go

@@ -440,7 +440,7 @@ func (hd *HeaderDownload) requestMoreHeadersForPOS(currentTime time.Time) (timeo
 		Anchor:  anchor,
 		Hash:    anchor.parentHash,
 		Number:  anchor.blockHeight - 1,
-		Length:  192,
+		Length:  128,
 		Skip:    0,
 		Reverse: true,
 	}
@@ -456,7 +456,7 @@ func (hd *HeaderDownload) UpdateStats(req *HeaderRequest, skeleton bool) {
 			hd.stats.SkeletonReqMinBlock = req.Number
 		}
 		if req.Number+req.Length*req.Skip > hd.stats.SkeletonReqMaxBlock {
-			hd.stats.SkeletonReqMaxBlock = req.Number + req.Length*req.Skip
+			hd.stats.SkeletonReqMaxBlock = req.Number + req.Length*(req.Skip+1)
 		}
 	} else {
 		hd.stats.Requests++
@@ -489,7 +489,7 @@ func (hd *HeaderDownload) RequestSkeleton() *HeaderRequest {
 	hd.lock.RLock()
 	defer hd.lock.RUnlock()
 	log.Debug("[Downloader] Request skeleton", "anchors", len(hd.anchors), "top seen height", hd.topSeenHeightPoW, "highestInDb", hd.highestInDb)
-	stride := uint64(8 * 192)
+	stride := uint64(1) // Fix for BSC, for some reason most peers cannot response to the skeleton requests with non-zero strides anymore, so we are getting stuck very frequently
 	strideHeight := hd.highestInDb + stride
 	var length uint64 = 192
 	return &HeaderRequest{Number: strideHeight, Length: length, Skip: stride - 1, Reverse: false}