eth: use finalized count for total protection, keep EMA on inclusions

Change the long-term protection category from total inclusions to
total finalized inclusions. Finalized txs are harder to game (require
actual block finality, not just inclusion) and represent confirmed
on-chain value.

The recent-inclusion EMA stays on chain head inclusions for
responsiveness — a peer delivering txs that appear in the latest
blocks gets quick protection without waiting for finalization.

The tracker now checks CurrentFinalBlock() on each chain head event
and credits delivering peers for all newly finalized blocks since
the last check.

eth/backend.go

@@ -467,7 +467,7 @@ func (s *Ethereum) Start() error {
 		stats := s.handler.txTracker.GetAllPeerStats()
 		result := make(map[string]PeerInclusionStats, len(stats))
 		for id, ps := range stats {
-			result[id] = PeerInclusionStats{Included: ps.Included, RecentIncluded: ps.RecentIncluded}
+			result[id] = PeerInclusionStats{Finalized: ps.Finalized, RecentIncluded: ps.RecentIncluded}
 		}
 		return result
 	})

eth/dropper.go

@@ -61,7 +61,7 @@ var (
 // to decide which peers to protect. Any stats provider (e.g. txtracker) can
 // implement getPeerInclusionStatsFunc by returning this struct per peer ID.
 type PeerInclusionStats struct {
-	Included       int64   // Cumulative on-chain inclusions attributed to this peer
+	Finalized      int64   // Cumulative finalized inclusions attributed to this peer
 	RecentIncluded float64 // EMA of per-block inclusions (0 if not tracked)
 }
 
@@ -79,7 +79,7 @@ type protectionCategory struct {
 // protectionCategories is the list of protection criteria. Each category
 // independently selects its top-N peers per pool; the union is protected.
 var protectionCategories = []protectionCategory{
-	{"total-included", func(s PeerInclusionStats) float64 { return float64(s.Included) }, inclusionProtectionFrac},
+	{"total-finalized", func(s PeerInclusionStats) float64 { return float64(s.Finalized) }, inclusionProtectionFrac},
 	{"recent-included", func(s PeerInclusionStats) float64 { return s.RecentIncluded }, inclusionProtectionFrac},
 }
 

eth/txtracker/tracker.go

@@ -22,18 +22,19 @@ const (
 
 // PeerStats holds the per-peer inclusion data.
 type PeerStats struct {
-	Included       int64   // Cumulative on-chain inclusions attributed to this peer
-	RecentIncluded float64 // EMA of per-block inclusions
+	Finalized      int64   // Cumulative finalized inclusions attributed to this peer
+	RecentIncluded float64 // EMA of per-block inclusions (at chain head time)
 }
 
 // Chain is the blockchain interface needed by the tracker.
 type Chain interface {
 	SubscribeChainHeadEvent(ch chan<- core.ChainHeadEvent) event.Subscription
 	GetBlockByNumber(number uint64) *types.Block
+	CurrentFinalBlock() *types.Header
 }
 
 type peerStats struct {
-	included       int64
+	finalized      int64
 	recentIncluded float64
 }
 
@@ -45,9 +46,10 @@ type Tracker struct {
 	peers map[string]*peerStats
 	order []common.Hash // insertion order for LRU eviction
 
-	chain  Chain
-	headCh chan core.ChainHeadEvent
-	sub    event.Subscription
+	chain        Chain
+	lastFinalNum uint64 // last finalized block number processed
+	headCh       chan core.ChainHeadEvent
+	sub          event.Subscription
 
 	quit chan struct{}
 	wg   sync.WaitGroup
@@ -109,7 +111,7 @@ func (t *Tracker) GetAllPeerStats() map[string]PeerStats {
 	result := make(map[string]PeerStats, len(t.peers))
 	for id, ps := range t.peers {
 		result[id] = PeerStats{
-			Included:       ps.included,
+			Finalized:      ps.finalized,
 			RecentIncluded: ps.recentIncluded,
 		}
 	}
@@ -132,6 +134,7 @@ func (t *Tracker) loop() {
 }
 
 func (t *Tracker) handleChainHead(ev core.ChainHeadEvent) {
+	// Update recent-inclusion EMA from the new head block.
 	block := t.chain.GetBlockByNumber(ev.Header.Number.Uint64())
 	if block == nil {
 		return
@@ -139,27 +142,56 @@ func (t *Tracker) handleChainHead(ev core.ChainHeadEvent) {
 	t.mu.Lock()
 	defer t.mu.Unlock()
 
-	// Credit delivering peers for each included transaction.
+	// Count per-peer inclusions in this block for the EMA.
 	blockIncl := make(map[string]int)
 	for _, tx := range block.Transactions() {
-		hash := tx.Hash()
-		peer, ok := t.txs[hash]
-		if !ok || peer == "" {
-			continue
+		if peer := t.txs[tx.Hash()]; peer != "" {
+			blockIncl[peer]++
 		}
-		ps := t.peers[peer]
-		if ps == nil {
-			ps = &peerStats{}
-			t.peers[peer] = ps
-		}
-		ps.included++
-		blockIncl[peer]++
 	}
-	// Update per-peer recent-inclusion EMA for all tracked peers.
+	// Update EMA for all tracked peers (decay inactive ones).
 	for peer, ps := range t.peers {
 		ps.recentIncluded = (1-emaAlpha)*ps.recentIncluded + emaAlpha*float64(blockIncl[peer])
 	}
-	if len(blockIncl) > 0 {
-		log.Trace("Credited peers for block inclusions", "block", ev.Header.Number, "peers", len(blockIncl))
-	}
+	// Check if the finalized block has advanced.
+	t.checkFinalization()
+}
+
+// checkFinalization credits peers for transactions in newly finalized blocks.
+// Must be called with t.mu held.
+func (t *Tracker) checkFinalization() {
+	finalHeader := t.chain.CurrentFinalBlock()
+	if finalHeader == nil {
+		return
+	}
+	finalNum := finalHeader.Number.Uint64()
+	if finalNum <= t.lastFinalNum {
+		return
+	}
+	// Credit peers for all blocks from lastFinalNum+1 to finalNum.
+	var credited int
+	for num := t.lastFinalNum + 1; num <= finalNum; num++ {
+		block := t.chain.GetBlockByNumber(num)
+		if block == nil {
+			continue
+		}
+		for _, tx := range block.Transactions() {
+			peer := t.txs[tx.Hash()]
+			if peer == "" {
+				continue
+			}
+			ps := t.peers[peer]
+			if ps == nil {
+				ps = &peerStats{}
+				t.peers[peer] = ps
+			}
+			ps.finalized++
+			credited++
+		}
+	}
+	if credited > 0 {
+		log.Trace("Credited peers for finalized inclusions",
+			"from", t.lastFinalNum+1, "to", finalNum, "txs", credited)
+	}
+	t.lastFinalNum = finalNum
 }