eth/fetcher: fix blob transaction propagation (#30125)

This PR fixes an issue with blob transaction propagation due to the blob
transation txpool rejecting transactions with gapped nonces. The
specific changes are:

- fetch transactions from a peer in the order they were announced to
minimize nonce-gaps (which cause blob txs to be rejected

- don't wait on fetching blob transactions after announcement is
received, since they are not broadcast

Testing:
- unit tests updated to reflect that fetch order should always match tx
announcement order
- unit test added to confirm blob transactions are scheduled immediately
for fetching
  - running the PR on an eth mainnet full node without incident so far

---------

Signed-off-by: Roberto Bayardo <bayardo@alum.mit.edu>
Co-authored-by: Gary Rong <garyrong0905@gmail.com>

cmd/devp2p/internal/ethtest/suite.go

@@ -849,8 +849,17 @@ func (s *Suite) TestBlobViolations(t *utesting.T) {
 		if code, _, err := conn.Read(); err != nil {
 			t.Fatalf("expected disconnect on blob violation, got err: %v", err)
 		} else if code != discMsg {
+			if code == protoOffset(ethProto)+eth.NewPooledTransactionHashesMsg {
+				// sometimes we'll get a blob transaction hashes announcement before the disconnect
+				// because blob transactions are scheduled to be fetched right away.
+				if code, _, err = conn.Read(); err != nil {
+					t.Fatalf("expected disconnect on blob violation, got err on second read: %v", err)
+				}
+			}
+			if code != discMsg {
 				t.Fatalf("expected disconnect on blob violation, got msg code: %d", code)
 			}
+		}
 		conn.Close()
 	}
 }

eth/fetcher/tx_fetcher.go

@@ -17,7 +17,6 @@
 package fetcher
 
 import (
-	"bytes"
 	"errors"
 	"fmt"
 	"math"
@@ -35,7 +34,7 @@ import (
 )
 
 const (
-	// maxTxAnnounces is the maximum number of unique transaction a peer
+	// maxTxAnnounces is the maximum number of unique transactions a peer
 	// can announce in a short time.
 	maxTxAnnounces = 4096
 
@@ -114,16 +113,23 @@ var errTerminated = errors.New("terminated")
 type txAnnounce struct {
 	origin string        // Identifier of the peer originating the notification
 	hashes []common.Hash // Batch of transaction hashes being announced
-	metas  []*txMetadata // Batch of metadata associated with the hashes
+	metas  []txMetadata  // Batch of metadata associated with the hashes
 }
 
-// txMetadata is a set of extra data transmitted along the announcement for better
+// txMetadata provides the extra data transmitted along with the announcement
-// fetch scheduling.
+// for better fetch scheduling.
 type txMetadata struct {
 	kind byte   // Transaction consensus type
 	size uint32 // Transaction size in bytes
 }
 
+// txMetadataWithSeq is a wrapper of transaction metadata with an extra field
+// tracking the transaction sequence number.
+type txMetadataWithSeq struct {
+	txMetadata
+	seq uint64
+}
+
 // txRequest represents an in-flight transaction retrieval request destined to
 // a specific peers.
 type txRequest struct {
@@ -159,7 +165,7 @@ type txDrop struct {
 // The invariants of the fetcher are:
 //   - Each tracked transaction (hash) must only be present in one of the
 //     three stages. This ensures that the fetcher operates akin to a finite
-//     state automata and there's do data leak.
+//     state automata and there's no data leak.
 //   - Each peer that announced transactions may be scheduled retrievals, but
 //     only ever one concurrently. This ensures we can immediately know what is
 //     missing from a reply and reschedule it.
@@ -169,17 +175,18 @@ type TxFetcher struct {
 	drop    chan *txDrop
 	quit    chan struct{}
 
+	txSeq       uint64                             // Unique transaction sequence number
 	underpriced *lru.Cache[common.Hash, time.Time] // Transactions discarded as too cheap (don't re-fetch)
 
 	// Stage 1: Waiting lists for newly discovered transactions that might be
 	// broadcast without needing explicit request/reply round trips.
 	waitlist  map[common.Hash]map[string]struct{}           // Transactions waiting for an potential broadcast
 	waittime  map[common.Hash]mclock.AbsTime                // Timestamps when transactions were added to the waitlist
-	waitslots map[string]map[common.Hash]*txMetadata // Waiting announcements grouped by peer (DoS protection)
+	waitslots map[string]map[common.Hash]*txMetadataWithSeq // Waiting announcements grouped by peer (DoS protection)
 
 	// Stage 2: Queue of transactions that waiting to be allocated to some peer
 	// to be retrieved directly.
-	announces map[string]map[common.Hash]*txMetadata // Set of announced transactions, grouped by origin peer
+	announces map[string]map[common.Hash]*txMetadataWithSeq // Set of announced transactions, grouped by origin peer
 	announced map[common.Hash]map[string]struct{}           // Set of download locations, grouped by transaction hash
 
 	// Stage 3: Set of transactions currently being retrieved, some which may be
@@ -218,8 +225,8 @@ func NewTxFetcherForTests(
 		quit:        make(chan struct{}),
 		waitlist:    make(map[common.Hash]map[string]struct{}),
 		waittime:    make(map[common.Hash]mclock.AbsTime),
-		waitslots:   make(map[string]map[common.Hash]*txMetadata),
+		waitslots:   make(map[string]map[common.Hash]*txMetadataWithSeq),
-		announces:   make(map[string]map[common.Hash]*txMetadata),
+		announces:   make(map[string]map[common.Hash]*txMetadataWithSeq),
 		announced:   make(map[common.Hash]map[string]struct{}),
 		fetching:    make(map[common.Hash]string),
 		requests:    make(map[string]*txRequest),
@@ -247,7 +254,7 @@ func (f *TxFetcher) Notify(peer string, types []byte, sizes []uint32, hashes []c
 	// loop, so anything caught here is time saved internally.
 	var (
 		unknownHashes = make([]common.Hash, 0, len(hashes))
-		unknownMetas  = make([]*txMetadata, 0, len(hashes))
+		unknownMetas  = make([]txMetadata, 0, len(hashes))
 
 		duplicate   int64
 		underpriced int64
@@ -264,7 +271,7 @@ func (f *TxFetcher) Notify(peer string, types []byte, sizes []uint32, hashes []c
 			// Transaction metadata has been available since eth68, and all
 			// legacy eth protocols (prior to eth68) have been deprecated.
 			// Therefore, metadata is always expected in the announcement.
-			unknownMetas = append(unknownMetas, &txMetadata{kind: types[i], size: sizes[i]})
+			unknownMetas = append(unknownMetas, txMetadata{kind: types[i], size: sizes[i]})
 		}
 	}
 	txAnnounceKnownMeter.Mark(duplicate)
@@ -431,9 +438,19 @@ func (f *TxFetcher) loop() {
 				ann.metas = ann.metas[:want-maxTxAnnounces]
 			}
 			// All is well, schedule the remainder of the transactions
-			idleWait := len(f.waittime) == 0
+			var (
-			_, oldPeer := f.announces[ann.origin]
+				idleWait   = len(f.waittime) == 0
+				_, oldPeer = f.announces[ann.origin]
+				hasBlob    bool
 
+				// nextSeq returns the next available sequence number for tagging
+				// transaction announcement and also bump it internally.
+				nextSeq = func() uint64 {
+					seq := f.txSeq
+					f.txSeq++
+					return seq
+				}
+			)
 			for i, hash := range ann.hashes {
 				// If the transaction is already downloading, add it to the list
 				// of possible alternates (in case the current retrieval fails) and
@@ -443,9 +460,17 @@ func (f *TxFetcher) loop() {
 
 					// Stage 2 and 3 share the set of origins per tx
 					if announces := f.announces[ann.origin]; announces != nil {
-						announces[hash] = ann.metas[i]
+						announces[hash] = &txMetadataWithSeq{
+							txMetadata: ann.metas[i],
+							seq:        nextSeq(),
+						}
 					} else {
-						f.announces[ann.origin] = map[common.Hash]*txMetadata{hash: ann.metas[i]}
+						f.announces[ann.origin] = map[common.Hash]*txMetadataWithSeq{
+							hash: {
+								txMetadata: ann.metas[i],
+								seq:        nextSeq(),
+							},
+						}
 					}
 					continue
 				}
@@ -456,9 +481,17 @@ func (f *TxFetcher) loop() {
 
 					// Stage 2 and 3 share the set of origins per tx
 					if announces := f.announces[ann.origin]; announces != nil {
-						announces[hash] = ann.metas[i]
+						announces[hash] = &txMetadataWithSeq{
+							txMetadata: ann.metas[i],
+							seq:        nextSeq(),
+						}
 					} else {
-						f.announces[ann.origin] = map[common.Hash]*txMetadata{hash: ann.metas[i]}
+						f.announces[ann.origin] = map[common.Hash]*txMetadataWithSeq{
+							hash: {
+								txMetadata: ann.metas[i],
+								seq:        nextSeq(),
+							},
+						}
 					}
 					continue
 				}
@@ -475,24 +508,47 @@ func (f *TxFetcher) loop() {
 					f.waitlist[hash][ann.origin] = struct{}{}
 
 					if waitslots := f.waitslots[ann.origin]; waitslots != nil {
-						waitslots[hash] = ann.metas[i]
+						waitslots[hash] = &txMetadataWithSeq{
+							txMetadata: ann.metas[i],
+							seq:        nextSeq(),
+						}
 					} else {
-						f.waitslots[ann.origin] = map[common.Hash]*txMetadata{hash: ann.metas[i]}
+						f.waitslots[ann.origin] = map[common.Hash]*txMetadataWithSeq{
+							hash: {
+								txMetadata: ann.metas[i],
+								seq:        nextSeq(),
+							},
+						}
 					}
 					continue
 				}
 				// Transaction unknown to the fetcher, insert it into the waiting list
 				f.waitlist[hash] = map[string]struct{}{ann.origin: {}}
-				f.waittime[hash] = f.clock.Now()
 
+				// Assign the current timestamp as the wait time, but for blob transactions,
+				// skip the wait time since they are only announced.
+				if ann.metas[i].kind != types.BlobTxType {
+					f.waittime[hash] = f.clock.Now()
+				} else {
+					hasBlob = true
+					f.waittime[hash] = f.clock.Now() - mclock.AbsTime(txArriveTimeout)
+				}
 				if waitslots := f.waitslots[ann.origin]; waitslots != nil {
-					waitslots[hash] = ann.metas[i]
+					waitslots[hash] = &txMetadataWithSeq{
+						txMetadata: ann.metas[i],
+						seq:        nextSeq(),
+					}
 				} else {
-					f.waitslots[ann.origin] = map[common.Hash]*txMetadata{hash: ann.metas[i]}
+					f.waitslots[ann.origin] = map[common.Hash]*txMetadataWithSeq{
+						hash: {
+							txMetadata: ann.metas[i],
+							seq:        nextSeq(),
+						},
+					}
 				}
 			}
 			// If a new item was added to the waitlist, schedule it into the fetcher
-			if idleWait && len(f.waittime) > 0 {
+			if hasBlob || (idleWait && len(f.waittime) > 0) {
 				f.rescheduleWait(waitTimer, waitTrigger)
 			}
 			// If this peer is new and announced something already queued, maybe
@@ -516,7 +572,7 @@ func (f *TxFetcher) loop() {
 						if announces := f.announces[peer]; announces != nil {
 							announces[hash] = f.waitslots[peer][hash]
 						} else {
-							f.announces[peer] = map[common.Hash]*txMetadata{hash: f.waitslots[peer][hash]}
+							f.announces[peer] = map[common.Hash]*txMetadataWithSeq{hash: f.waitslots[peer][hash]}
 						}
 						delete(f.waitslots[peer], hash)
 						if len(f.waitslots[peer]) == 0 {
@@ -873,7 +929,7 @@ func (f *TxFetcher) scheduleFetches(timer *mclock.Timer, timeout chan struct{},
 			hashes = make([]common.Hash, 0, maxTxRetrievals)
 			bytes  uint64
 		)
-		f.forEachAnnounce(f.announces[peer], func(hash common.Hash, meta *txMetadata) bool {
+		f.forEachAnnounce(f.announces[peer], func(hash common.Hash, meta txMetadata) bool {
 			// If the transaction is already fetching, skip to the next one
 			if _, ok := f.fetching[hash]; ok {
 				return true
@@ -938,28 +994,26 @@ func (f *TxFetcher) forEachPeer(peers map[string]struct{}, do func(peer string))
 	}
 }
 
-// forEachAnnounce does a range loop over a map of announcements in production,
+// forEachAnnounce loops over the given announcements in arrival order, invoking
-// but during testing it does a deterministic sorted random to allow reproducing
+// the do function for each until it returns false. We enforce an arrival
-// issues.
+// ordering to minimize the chances of transaction nonce-gaps, which result in
-func (f *TxFetcher) forEachAnnounce(announces map[common.Hash]*txMetadata, do func(hash common.Hash, meta *txMetadata) bool) {
+// transactions being rejected by the txpool.
-	// If we're running production, use whatever Go's map gives us
+func (f *TxFetcher) forEachAnnounce(announces map[common.Hash]*txMetadataWithSeq, do func(hash common.Hash, meta txMetadata) bool) {
-	if f.rand == nil {
+	type announcement struct {
-		for hash, meta := range announces {
+		hash common.Hash
-			if !do(hash, meta) {
+		meta txMetadata
-				return
+		seq  uint64
-			}
 	}
-		return
+	// Process announcements by their arrival order
+	list := make([]announcement, 0, len(announces))
+	for hash, entry := range announces {
+		list = append(list, announcement{hash: hash, meta: entry.txMetadata, seq: entry.seq})
 	}
-	// We're running the test suite, make iteration deterministic
+	sort.Slice(list, func(i, j int) bool {
-	list := make([]common.Hash, 0, len(announces))
+		return list[i].seq < list[j].seq
-	for hash := range announces {
+	})
-		list = append(list, hash)
+	for i := range list {
-	}
+		if !do(list[i].hash, list[i].meta) {
-	sortHashes(list)
-	rotateHashes(list, f.rand.Intn(len(list)))
-	for _, hash := range list {
-		if !do(hash, announces[hash]) {
 			return
 		}
 	}
@@ -975,26 +1029,3 @@ func rotateStrings(slice []string, n int) {
 		slice[i] = orig[(i+n)%len(orig)]
 	}
 }
-
-// sortHashes sorts a slice of hashes. This method is only used in tests in order
-// to simulate random map iteration but keep it deterministic.
-func sortHashes(slice []common.Hash) {
-	for i := 0; i < len(slice); i++ {
-		for j := i + 1; j < len(slice); j++ {
-			if bytes.Compare(slice[i][:], slice[j][:]) > 0 {
-				slice[i], slice[j] = slice[j], slice[i]
-			}
-		}
-	}
-}
-
-// rotateHashes rotates the contents of a slice by n steps. This method is only
-// used in tests to simulate random map iteration but keep it deterministic.
-func rotateHashes(slice []common.Hash, n int) {
-	orig := make([]common.Hash, len(slice))
-	copy(orig, slice)
-
-	for i := 0; i < len(orig); i++ {
-		slice[i] = orig[(i+n)%len(orig)]
-	}
-}

eth/fetcher/tx_fetcher_test.go

@@ -701,7 +701,7 @@ func TestTransactionFetcherMissingRescheduling(t *testing.T) {
 			},
 			// Deliver the middle transaction requested, the one before which
 			// should be dropped and the one after re-requested.
-			doTxEnqueue{peer: "A", txs: []*types.Transaction{testTxs[0]}, direct: true}, // This depends on the deterministic random
+			doTxEnqueue{peer: "A", txs: []*types.Transaction{testTxs[1]}, direct: true},
 			isScheduled{
 				tracking: map[string][]announce{
 					"A": {
@@ -1070,7 +1070,7 @@ func TestTransactionFetcherRateLimiting(t *testing.T) {
 					"A": announces,
 				},
 				fetching: map[string][]common.Hash{
-					"A": hashes[1643 : 1643+maxTxRetrievals],
+					"A": hashes[:maxTxRetrievals],
 				},
 			},
 		},
@@ -1130,9 +1130,9 @@ func TestTransactionFetcherBandwidthLimiting(t *testing.T) {
 					},
 				},
 				fetching: map[string][]common.Hash{
-					"A": {{0x02}, {0x03}, {0x04}},
+					"A": {{0x01}, {0x02}, {0x03}},
-					"B": {{0x06}},
+					"B": {{0x05}},
-					"C": {{0x08}},
+					"C": {{0x07}},
 				},
 			},
 		},
@@ -1209,8 +1209,8 @@ func TestTransactionFetcherDoSProtection(t *testing.T) {
 					"B": announceB[:maxTxAnnounces/2-1],
 				},
 				fetching: map[string][]common.Hash{
-					"A": hashesA[1643 : 1643+maxTxRetrievals],
+					"A": hashesA[:maxTxRetrievals],
-					"B": append(append([]common.Hash{}, hashesB[maxTxAnnounces/2-3:maxTxAnnounces/2-1]...), hashesB[:maxTxRetrievals-2]...),
+					"B": hashesB[:maxTxRetrievals],
 				},
 			},
 			// Ensure that adding even one more hash results in dropping the hash
@@ -1227,8 +1227,8 @@ func TestTransactionFetcherDoSProtection(t *testing.T) {
 					"B": announceB[:maxTxAnnounces/2-1],
 				},
 				fetching: map[string][]common.Hash{
-					"A": hashesA[1643 : 1643+maxTxRetrievals],
+					"A": hashesA[:maxTxRetrievals],
-					"B": append(append([]common.Hash{}, hashesB[maxTxAnnounces/2-3:maxTxAnnounces/2-1]...), hashesB[:maxTxRetrievals-2]...),
+					"B": hashesB[:maxTxRetrievals],
 				},
 			},
 		},
@@ -1759,6 +1759,76 @@ func TestTransactionFetcherFuzzCrash04(t *testing.T) {
 	})
 }
 
+// This test ensures the blob transactions will be scheduled for fetching
+// once they are announced in the network.
+func TestBlobTransactionAnnounce(t *testing.T) {
+	testTransactionFetcherParallel(t, txFetcherTest{
+		init: func() *TxFetcher {
+			return NewTxFetcher(
+				func(common.Hash) bool { return false },
+				nil,
+				func(string, []common.Hash) error { return nil },
+				nil,
+			)
+		},
+		steps: []interface{}{
+			// Initial announcement to get something into the waitlist
+			doTxNotify{peer: "A", hashes: []common.Hash{{0x01}, {0x02}}, types: []byte{types.LegacyTxType, types.LegacyTxType}, sizes: []uint32{111, 222}},
+			isWaiting(map[string][]announce{
+				"A": {
+					{common.Hash{0x01}, types.LegacyTxType, 111},
+					{common.Hash{0x02}, types.LegacyTxType, 222},
+				},
+			}),
+			// Announce a blob transaction
+			doTxNotify{peer: "B", hashes: []common.Hash{{0x03}}, types: []byte{types.BlobTxType}, sizes: []uint32{333}},
+			isWaiting(map[string][]announce{
+				"A": {
+					{common.Hash{0x01}, types.LegacyTxType, 111},
+					{common.Hash{0x02}, types.LegacyTxType, 222},
+				},
+				"B": {
+					{common.Hash{0x03}, types.BlobTxType, 333},
+				},
+			}),
+			doWait{time: 0, step: true}, // zero time, but the blob fetching should be scheduled
+			isWaiting(map[string][]announce{
+				"A": {
+					{common.Hash{0x01}, types.LegacyTxType, 111},
+					{common.Hash{0x02}, types.LegacyTxType, 222},
+				},
+			}),
+			isScheduled{
+				tracking: map[string][]announce{
+					"B": {
+						{common.Hash{0x03}, types.BlobTxType, 333},
+					},
+				},
+				fetching: map[string][]common.Hash{ // Depends on deterministic test randomizer
+					"B": {{0x03}},
+				},
+			},
+			doWait{time: txArriveTimeout, step: true}, // zero time, but the blob fetching should be scheduled
+			isWaiting(nil),
+			isScheduled{
+				tracking: map[string][]announce{
+					"A": {
+						{common.Hash{0x01}, types.LegacyTxType, 111},
+						{common.Hash{0x02}, types.LegacyTxType, 222},
+					},
+					"B": {
+						{common.Hash{0x03}, types.BlobTxType, 333},
+					},
+				},
+				fetching: map[string][]common.Hash{ // Depends on deterministic test randomizer
+					"A": {{0x01}, {0x02}},
+					"B": {{0x03}},
+				},
+			},
+		},
+	})
+}
+
 func testTransactionFetcherParallel(t *testing.T, tt txFetcherTest) {
 	t.Parallel()
 	testTransactionFetcher(t, tt)