eth/protocols, prp/tracker: add support for req/rep rtt tracking (#22608)

* eth/protocols, prp/tracker: add support for req/rep rtt tracking

* p2p/tracker: sanity cap the number of pending requests

* pap/tracker: linter <3

* p2p/tracker: disable entire tracker if no metrics are enabled

eth/protocols/eth/handler.go

@@ -223,7 +223,7 @@ func handleMessage(backend Backend, peer *Peer) error {
 	if peer.Version() >= ETH66 {
 		handlers = eth66
 	}
-	// Track the emount of time it takes to serve the request and run the handler
+	// Track the amount of time it takes to serve the request and run the handler
 	if metrics.Enabled {
 		h := fmt.Sprintf("%s/%s/%d/%#02x", p2p.HandleHistName, ProtocolName, peer.Version(), msg.Code)
 		defer func(start time.Time) {

eth/protocols/eth/handlers.go

@@ -327,6 +327,8 @@ func handleBlockHeaders66(backend Backend, msg Decoder, peer *Peer) error {
 	if err := msg.Decode(res); err != nil {
 		return fmt.Errorf("%w: message %v: %v", errDecode, msg, err)
 	}
+	requestTracker.Fulfil(peer.id, peer.version, BlockHeadersMsg, res.RequestId)
+
 	return backend.Handle(peer, &res.BlockHeadersPacket)
 }
 
@@ -345,6 +347,8 @@ func handleBlockBodies66(backend Backend, msg Decoder, peer *Peer) error {
 	if err := msg.Decode(res); err != nil {
 		return fmt.Errorf("%w: message %v: %v", errDecode, msg, err)
 	}
+	requestTracker.Fulfil(peer.id, peer.version, BlockBodiesMsg, res.RequestId)
+
 	return backend.Handle(peer, &res.BlockBodiesPacket)
 }
 
@@ -363,6 +367,8 @@ func handleNodeData66(backend Backend, msg Decoder, peer *Peer) error {
 	if err := msg.Decode(res); err != nil {
 		return fmt.Errorf("%w: message %v: %v", errDecode, msg, err)
 	}
+	requestTracker.Fulfil(peer.id, peer.version, NodeDataMsg, res.RequestId)
+
 	return backend.Handle(peer, &res.NodeDataPacket)
 }
 
@@ -381,6 +387,8 @@ func handleReceipts66(backend Backend, msg Decoder, peer *Peer) error {
 	if err := msg.Decode(res); err != nil {
 		return fmt.Errorf("%w: message %v: %v", errDecode, msg, err)
 	}
+	requestTracker.Fulfil(peer.id, peer.version, ReceiptsMsg, res.RequestId)
+
 	return backend.Handle(peer, &res.ReceiptsPacket)
 }
 
@@ -506,5 +514,7 @@ func handlePooledTransactions66(backend Backend, msg Decoder, peer *Peer) error
 		}
 		peer.markTransaction(tx.Hash())
 	}
+	requestTracker.Fulfil(peer.id, peer.version, PooledTransactionsMsg, txs.RequestId)
+
 	return backend.Handle(peer, &txs.PooledTransactionsPacket)
 }

eth/protocols/eth/peer.go

@@ -413,8 +413,11 @@ func (p *Peer) RequestOneHeader(hash common.Hash) error {
 		Reverse: false,
 	}
 	if p.Version() >= ETH66 {
+		id := rand.Uint64()
+
+		requestTracker.Track(p.id, p.version, GetBlockHeadersMsg, BlockHeadersMsg, id)
 		return p2p.Send(p.rw, GetBlockHeadersMsg, &GetBlockHeadersPacket66{
-			RequestId:             rand.Uint64(),
+			RequestId:             id,
 			GetBlockHeadersPacket: &query,
 		})
 	}
@@ -432,8 +435,11 @@ func (p *Peer) RequestHeadersByHash(origin common.Hash, amount int, skip int, re
 		Reverse: reverse,
 	}
 	if p.Version() >= ETH66 {
+		id := rand.Uint64()
+
+		requestTracker.Track(p.id, p.version, GetBlockHeadersMsg, BlockHeadersMsg, id)
 		return p2p.Send(p.rw, GetBlockHeadersMsg, &GetBlockHeadersPacket66{
-			RequestId:             rand.Uint64(),
+			RequestId:             id,
 			GetBlockHeadersPacket: &query,
 		})
 	}
@@ -451,8 +457,11 @@ func (p *Peer) RequestHeadersByNumber(origin uint64, amount int, skip int, rever
 		Reverse: reverse,
 	}
 	if p.Version() >= ETH66 {
+		id := rand.Uint64()
+
+		requestTracker.Track(p.id, p.version, GetBlockHeadersMsg, BlockHeadersMsg, id)
 		return p2p.Send(p.rw, GetBlockHeadersMsg, &GetBlockHeadersPacket66{
-			RequestId:             rand.Uint64(),
+			RequestId:             id,
 			GetBlockHeadersPacket: &query,
 		})
 	}
@@ -476,8 +485,11 @@ func (p *Peer) ExpectRequestHeadersByNumber(origin uint64, amount int, skip int,
 func (p *Peer) RequestBodies(hashes []common.Hash) error {
 	p.Log().Debug("Fetching batch of block bodies", "count", len(hashes))
 	if p.Version() >= ETH66 {
+		id := rand.Uint64()
+
+		requestTracker.Track(p.id, p.version, GetBlockBodiesMsg, BlockBodiesMsg, id)
 		return p2p.Send(p.rw, GetBlockBodiesMsg, &GetBlockBodiesPacket66{
-			RequestId:            rand.Uint64(),
+			RequestId:            id,
 			GetBlockBodiesPacket: hashes,
 		})
 	}
@@ -489,8 +501,11 @@ func (p *Peer) RequestBodies(hashes []common.Hash) error {
 func (p *Peer) RequestNodeData(hashes []common.Hash) error {
 	p.Log().Debug("Fetching batch of state data", "count", len(hashes))
 	if p.Version() >= ETH66 {
+		id := rand.Uint64()
+
+		requestTracker.Track(p.id, p.version, GetNodeDataMsg, NodeDataMsg, id)
 		return p2p.Send(p.rw, GetNodeDataMsg, &GetNodeDataPacket66{
-			RequestId:         rand.Uint64(),
+			RequestId:         id,
 			GetNodeDataPacket: hashes,
 		})
 	}
@@ -501,8 +516,11 @@ func (p *Peer) RequestNodeData(hashes []common.Hash) error {
 func (p *Peer) RequestReceipts(hashes []common.Hash) error {
 	p.Log().Debug("Fetching batch of receipts", "count", len(hashes))
 	if p.Version() >= ETH66 {
+		id := rand.Uint64()
+
+		requestTracker.Track(p.id, p.version, GetReceiptsMsg, ReceiptsMsg, id)
 		return p2p.Send(p.rw, GetReceiptsMsg, &GetReceiptsPacket66{
-			RequestId:         rand.Uint64(),
+			RequestId:         id,
 			GetReceiptsPacket: hashes,
 		})
 	}
@@ -513,8 +531,11 @@ func (p *Peer) RequestReceipts(hashes []common.Hash) error {
 func (p *Peer) RequestTxs(hashes []common.Hash) error {
 	p.Log().Debug("Fetching batch of transactions", "count", len(hashes))
 	if p.Version() >= ETH66 {
+		id := rand.Uint64()
+
+		requestTracker.Track(p.id, p.version, GetPooledTransactionsMsg, PooledTransactionsMsg, id)
 		return p2p.Send(p.rw, GetPooledTransactionsMsg, &GetPooledTransactionsPacket66{
-			RequestId:                   rand.Uint64(),
+			RequestId:                   id,
 			GetPooledTransactionsPacket: hashes,
 		})
 	}

eth/protocols/eth/tracker.go

@@ -0,0 +1,26 @@
+// Copyright 2021 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 eth
+
+import (
+	"time"
+
+	"github.com/ethereum/go-ethereum/p2p/tracker"
+)
+
+// requestTracker is a singleton tracker for eth/66 and newer request times.
+var requestTracker = tracker.New(ProtocolName, 5*time.Minute)

eth/protocols/snap/handler.go

@@ -227,6 +227,8 @@ func handleMessage(backend Backend, peer *Peer) error {
 				return fmt.Errorf("accounts not monotonically increasing: #%d [%x] vs #%d [%x]", i-1, res.Accounts[i-1].Hash[:], i, res.Accounts[i].Hash[:])
 			}
 		}
+		requestTracker.Fulfil(peer.id, peer.version, AccountRangeMsg, res.ID)
+
 		return backend.Handle(peer, res)
 
 	case msg.Code == GetStorageRangesMsg:
@@ -360,6 +362,8 @@ func handleMessage(backend Backend, peer *Peer) error {
 				}
 			}
 		}
+		requestTracker.Fulfil(peer.id, peer.version, StorageRangesMsg, res.ID)
+
 		return backend.Handle(peer, res)
 
 	case msg.Code == GetByteCodesMsg:
@@ -404,6 +408,8 @@ func handleMessage(backend Backend, peer *Peer) error {
 		if err := msg.Decode(res); err != nil {
 			return fmt.Errorf("%w: message %v: %v", errDecode, msg, err)
 		}
+		requestTracker.Fulfil(peer.id, peer.version, ByteCodesMsg, res.ID)
+
 		return backend.Handle(peer, res)
 
 	case msg.Code == GetTrieNodesMsg:
@@ -497,6 +503,8 @@ func handleMessage(backend Backend, peer *Peer) error {
 		if err := msg.Decode(res); err != nil {
 			return fmt.Errorf("%w: message %v: %v", errDecode, msg, err)
 		}
+		requestTracker.Fulfil(peer.id, peer.version, TrieNodesMsg, res.ID)
+
 		return backend.Handle(peer, res)
 
 	default:

eth/protocols/snap/peer.go

@@ -65,6 +65,8 @@ func (p *Peer) Log() log.Logger {
 // trie, starting with the origin.
 func (p *Peer) RequestAccountRange(id uint64, root common.Hash, origin, limit common.Hash, bytes uint64) error {
 	p.logger.Trace("Fetching range of accounts", "reqid", id, "root", root, "origin", origin, "limit", limit, "bytes", common.StorageSize(bytes))
+
+	requestTracker.Track(p.id, p.version, GetAccountRangeMsg, AccountRangeMsg, id)
 	return p2p.Send(p.rw, GetAccountRangeMsg, &GetAccountRangePacket{
 		ID:     id,
 		Root:   root,
@@ -83,6 +85,7 @@ func (p *Peer) RequestStorageRanges(id uint64, root common.Hash, accounts []comm
 	} else {
 		p.logger.Trace("Fetching ranges of small storage slots", "reqid", id, "root", root, "accounts", len(accounts), "first", accounts[0], "bytes", common.StorageSize(bytes))
 	}
+	requestTracker.Track(p.id, p.version, GetStorageRangesMsg, StorageRangesMsg, id)
 	return p2p.Send(p.rw, GetStorageRangesMsg, &GetStorageRangesPacket{
 		ID:       id,
 		Root:     root,
@@ -96,6 +99,8 @@ func (p *Peer) RequestStorageRanges(id uint64, root common.Hash, accounts []comm
 // RequestByteCodes fetches a batch of bytecodes by hash.
 func (p *Peer) RequestByteCodes(id uint64, hashes []common.Hash, bytes uint64) error {
 	p.logger.Trace("Fetching set of byte codes", "reqid", id, "hashes", len(hashes), "bytes", common.StorageSize(bytes))
+
+	requestTracker.Track(p.id, p.version, GetByteCodesMsg, ByteCodesMsg, id)
 	return p2p.Send(p.rw, GetByteCodesMsg, &GetByteCodesPacket{
 		ID:     id,
 		Hashes: hashes,
@@ -107,6 +112,8 @@ func (p *Peer) RequestByteCodes(id uint64, hashes []common.Hash, bytes uint64) e
 // a specificstate trie.
 func (p *Peer) RequestTrieNodes(id uint64, root common.Hash, paths []TrieNodePathSet, bytes uint64) error {
 	p.logger.Trace("Fetching set of trie nodes", "reqid", id, "root", root, "pathsets", len(paths), "bytes", common.StorageSize(bytes))
+
+	requestTracker.Track(p.id, p.version, GetTrieNodesMsg, TrieNodesMsg, id)
 	return p2p.Send(p.rw, GetTrieNodesMsg, &GetTrieNodesPacket{
 		ID:    id,
 		Root:  root,

eth/protocols/snap/tracker.go

@@ -0,0 +1,26 @@
+// Copyright 2021 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 snap
+
+import (
+	"time"
+
+	"github.com/ethereum/go-ethereum/p2p/tracker"
+)
+
+// requestTracker is a singleton tracker for request times.
+var requestTracker = tracker.New(ProtocolName, time.Minute)

p2p/metrics.go

@@ -33,9 +33,6 @@ const (
 
 	// HandleHistName is the prefix of the per-packet serving time histograms.
 	HandleHistName = "p2p/handle"
-
-	// WaitHistName is the prefix of the per-packet (req only) waiting time histograms.
-	WaitHistName = "p2p/wait"
 )
 
 var (

p2p/tracker/tracker.go

@@ -0,0 +1,203 @@
+// Copyright 2021 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 tracker
+
+import (
+	"container/list"
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/metrics"
+)
+
+const (
+	// trackedGaugeName is the prefix of the per-packet request tracking.
+	trackedGaugeName = "p2p/tracked"
+
+	// lostMeterName is the prefix of the per-packet request expirations.
+	lostMeterName = "p2p/lost"
+
+	// staleMeterName is the prefix of the per-packet stale responses.
+	staleMeterName = "p2p/stale"
+
+	// waitHistName is the prefix of the per-packet (req only) waiting time histograms.
+	waitHistName = "p2p/wait"
+
+	// maxTrackedPackets is a huge number to act as a failsafe on the number of
+	// pending requests the node will track. It should never be hit unless an
+	// attacker figures out a way to spin requests.
+	maxTrackedPackets = 100000
+)
+
+// request tracks sent network requests which have not yet received a response.
+type request struct {
+	peer    string
+	version uint // Protocol version
+
+	reqCode uint64 // Protocol message code of the request
+	resCode uint64 // Protocol message code of the expected response
+
+	time   time.Time     // Timestamp when the request was made
+	expire *list.Element // Expiration marker to untrack it
+}
+
+// Tracker is a pending network request tracker to measure how much time it takes
+// a remote peer to respond.
+type Tracker struct {
+	protocol string        // Protocol capability identifier for the metrics
+	timeout  time.Duration // Global timeout after which to drop a tracked packet
+
+	pending map[uint64]*request // Currently pending requests
+	expire  *list.List          // Linked list tracking the expiration order
+	wake    *time.Timer         // Timer tracking the expiration of the next item
+
+	lock sync.Mutex // Lock protecting from concurrent updates
+}
+
+// New creates a new network request tracker to monitor how much time it takes to
+// fill certain requests and how individual peers perform.
+func New(protocol string, timeout time.Duration) *Tracker {
+	return &Tracker{
+		protocol: protocol,
+		timeout:  timeout,
+		pending:  make(map[uint64]*request),
+		expire:   list.New(),
+	}
+}
+
+// Track adds a network request to the tracker to wait for a response to arrive
+// or until the request it cancelled or times out.
+func (t *Tracker) Track(peer string, version uint, reqCode uint64, resCode uint64, id uint64) {
+	if !metrics.Enabled {
+		return
+	}
+	t.lock.Lock()
+	defer t.lock.Unlock()
+
+	// If there's a duplicate request, we've just random-collided (or more probably,
+	// we have a bug), report it. We could also add a metric, but we're not really
+	// expecting ourselves to be buggy, so a noisy warning should be enough.
+	if _, ok := t.pending[id]; ok {
+		log.Error("Network request id collision", "protocol", t.protocol, "version", version, "code", reqCode, "id", id)
+		return
+	}
+	// If we have too many pending requests, bail out instead of leaking memory
+	if pending := len(t.pending); pending >= maxTrackedPackets {
+		log.Error("Request tracker exceeded allowance", "pending", pending, "peer", peer, "protocol", t.protocol, "version", version, "code", reqCode)
+		return
+	}
+	// Id doesn't exist yet, start tracking it
+	t.pending[id] = &request{
+		peer:    peer,
+		version: version,
+		reqCode: reqCode,
+		resCode: resCode,
+		time:    time.Now(),
+		expire:  t.expire.PushBack(id),
+	}
+	g := fmt.Sprintf("%s/%s/%d/%#02x", trackedGaugeName, t.protocol, version, reqCode)
+	metrics.GetOrRegisterGauge(g, nil).Inc(1)
+
+	// If we've just inserted the first item, start the expiration timer
+	if t.wake == nil {
+		t.wake = time.AfterFunc(t.timeout, t.clean)
+	}
+}
+
+// clean is called automatically when a preset time passes without a response
+// being dleivered for the first network request.
+func (t *Tracker) clean() {
+	t.lock.Lock()
+	defer t.lock.Unlock()
+
+	// Expire anything within a certain threshold (might be no items at all if
+	// we raced with the delivery)
+	for t.expire.Len() > 0 {
+		// Stop iterating if the next pending request is still alive
+		var (
+			head = t.expire.Front()
+			id   = head.Value.(uint64)
+			req  = t.pending[id]
+		)
+		if time.Since(req.time) < t.timeout+5*time.Millisecond {
+			break
+		}
+		// Nope, dead, drop it
+		t.expire.Remove(head)
+		delete(t.pending, id)
+
+		g := fmt.Sprintf("%s/%s/%d/%#02x", trackedGaugeName, t.protocol, req.version, req.reqCode)
+		metrics.GetOrRegisterGauge(g, nil).Dec(1)
+
+		m := fmt.Sprintf("%s/%s/%d/%#02x", lostMeterName, t.protocol, req.version, req.reqCode)
+		metrics.GetOrRegisterMeter(m, nil).Mark(1)
+	}
+	t.schedule()
+}
+
+// schedule starts a timer to trigger on the expiration of the first network
+// packet.
+func (t *Tracker) schedule() {
+	if t.expire.Len() == 0 {
+		t.wake = nil
+		return
+	}
+	t.wake = time.AfterFunc(time.Until(t.pending[t.expire.Front().Value.(uint64)].time.Add(t.timeout)), t.clean)
+}
+
+// Fulfil fills a pending request, if any is available, reporting on various metrics.
+func (t *Tracker) Fulfil(peer string, version uint, code uint64, id uint64) {
+	if !metrics.Enabled {
+		return
+	}
+	t.lock.Lock()
+	defer t.lock.Unlock()
+
+	// If it's a non existing request, track as stale response
+	req, ok := t.pending[id]
+	if !ok {
+		m := fmt.Sprintf("%s/%s/%d/%#02x", staleMeterName, t.protocol, version, code)
+		metrics.GetOrRegisterMeter(m, nil).Mark(1)
+		return
+	}
+	// If the response is funky, it might be some active attack
+	if req.peer != peer || req.version != version || req.resCode != code {
+		log.Warn("Network response id collision",
+			"have", fmt.Sprintf("%s:%s/%d:%d", peer, t.protocol, version, code),
+			"want", fmt.Sprintf("%s:%s/%d:%d", peer, t.protocol, req.version, req.resCode),
+		)
+		return
+	}
+	// Everything matches, mark the request serviced and meter it
+	t.expire.Remove(req.expire)
+	if req.expire.Prev() == nil {
+		t.wake.Stop()
+		t.schedule()
+	}
+	g := fmt.Sprintf("%s/%s/%d/%#02x", trackedGaugeName, t.protocol, req.version, req.reqCode)
+	metrics.GetOrRegisterGauge(g, nil).Dec(1)
+
+	h := fmt.Sprintf("%s/%s/%d/%#02x", waitHistName, t.protocol, req.version, req.reqCode)
+	sampler := func() metrics.Sample {
+		return metrics.ResettingSample(
+			metrics.NewExpDecaySample(1028, 0.015),
+		)
+	}
+	metrics.GetOrRegisterHistogramLazy(h, nil, sampler).Update(time.Since(req.time).Microseconds())
+}