From fc4fee8649f11e6ab500af3ee3a458d85fbd0867 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A9ter=20Szil=C3=A1gyi?= <peterke@gmail.com>
Date: Wed, 12 Jun 2019 12:30:06 +0300
Subject: [PATCH] eth: enforce stricter known limits on idle peers

---
 eth/peer.go | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/eth/peer.go b/eth/peer.go
index 54c0ea0d53..208badc5ed 100644
--- a/eth/peer.go
+++ b/eth/peer.go
@@ -196,9 +196,13 @@ func (p *peer) MarkTransaction(hash common.Hash) {
 // SendTransactions sends transactions to the peer and includes the hashes
 // in its transaction hash set for future reference.
 func (p *peer) SendTransactions(txs types.Transactions) error {
+	// Mark all the transactions as known, but ensure we don't overflow our limits
 	for _, tx := range txs {
 		p.knownTxs.Add(tx.Hash())
 	}
+	for p.knownTxs.Cardinality() >= maxKnownTxs {
+		p.knownTxs.Pop()
+	}
 	return p2p.Send(p.rw, TxMsg, txs)
 }
 
@@ -207,9 +211,13 @@ func (p *peer) SendTransactions(txs types.Transactions) error {
 func (p *peer) AsyncSendTransactions(txs []*types.Transaction) {
 	select {
 	case p.queuedTxs <- txs:
+		// Mark all the transactions as known, but ensure we don't overflow our limits
 		for _, tx := range txs {
 			p.knownTxs.Add(tx.Hash())
 		}
+		for p.knownTxs.Cardinality() >= maxKnownTxs {
+			p.knownTxs.Pop()
+		}
 	default:
 		p.Log().Debug("Dropping transaction propagation", "count", len(txs))
 	}
@@ -218,9 +226,13 @@ func (p *peer) AsyncSendTransactions(txs []*types.Transaction) {
 // SendNewBlockHashes announces the availability of a number of blocks through
 // a hash notification.
 func (p *peer) SendNewBlockHashes(hashes []common.Hash, numbers []uint64) error {
+	// Mark all the block hashes as known, but ensure we don't overflow our limits
 	for _, hash := range hashes {
 		p.knownBlocks.Add(hash)
 	}
+	for p.knownBlocks.Cardinality() >= maxKnownBlocks {
+		p.knownBlocks.Pop()
+	}
 	request := make(newBlockHashesData, len(hashes))
 	for i := 0; i < len(hashes); i++ {
 		request[i].Hash = hashes[i]
@@ -235,7 +247,11 @@ func (p *peer) SendNewBlockHashes(hashes []common.Hash, numbers []uint64) error
 func (p *peer) AsyncSendNewBlockHash(block *types.Block) {
 	select {
 	case p.queuedAnns <- block:
+		// Mark all the block hash as known, but ensure we don't overflow our limits
 		p.knownBlocks.Add(block.Hash())
+		for p.knownBlocks.Cardinality() >= maxKnownBlocks {
+			p.knownBlocks.Pop()
+		}
 	default:
 		p.Log().Debug("Dropping block announcement", "number", block.NumberU64(), "hash", block.Hash())
 	}
@@ -243,7 +259,11 @@ func (p *peer) AsyncSendNewBlockHash(block *types.Block) {
 
 // SendNewBlock propagates an entire block to a remote peer.
 func (p *peer) SendNewBlock(block *types.Block, td *big.Int) error {
+	// Mark all the block hash as known, but ensure we don't overflow our limits
 	p.knownBlocks.Add(block.Hash())
+	for p.knownBlocks.Cardinality() >= maxKnownBlocks {
+		p.knownBlocks.Pop()
+	}
 	return p2p.Send(p.rw, NewBlockMsg, []interface{}{block, td})
 }
 
@@ -252,7 +272,11 @@ func (p *peer) SendNewBlock(block *types.Block, td *big.Int) error {
 func (p *peer) AsyncSendNewBlock(block *types.Block, td *big.Int) {
 	select {
 	case p.queuedProps <- &propEvent{block: block, td: td}:
+		// Mark all the block hash as known, but ensure we don't overflow our limits
 		p.knownBlocks.Add(block.Hash())
+		for p.knownBlocks.Cardinality() >= maxKnownBlocks {
+			p.knownBlocks.Pop()
+		}
 	default:
 		p.Log().Debug("Dropping block propagation", "number", block.NumberU64(), "hash", block.Hash())
 	}