From d9dc3463d04e8fa98045200f610e20d17ae3605f Mon Sep 17 00:00:00 2001
From: Brannon King <countprimes@gmail.com>
Date: Thu, 14 Oct 2021 17:43:23 -0400
Subject: [PATCH] [lbry] don't ban peers on tx-not-in-block behavior

---
 server.go | 33 ++++++++++++++++++++-------------
 1 file changed, 20 insertions(+), 13 deletions(-)

diff --git a/server.go b/server.go
index 0e57f622..4aefb2c8 100644
--- a/server.go
+++ b/server.go
@@ -389,11 +389,13 @@ func (sp *serverPeer) addBanScore(persistent, transient uint32, reason string) b
 	}
 	score := sp.banScore.Increase(persistent, transient)
 	if score > warnThreshold {
-		peerLog.Warnf("Misbehaving peer %s: %s -- ban score increased to %d",
-			sp, reason, score)
+		peerLog.Warnf("Misbehaving peer %s: %s -- ban score increased to %d", sp, reason, score)
 		if score > cfg.BanThreshold {
-			peerLog.Warnf("Misbehaving peer %s -- banning and disconnecting",
-				sp)
+			if sp.server.ConnectedCount() <= 1 {
+				peerLog.Warnf("Refusing to ban peer %s as it is the only peer", sp)
+				return false
+			}
+			peerLog.Warnf("Misbehaving peer %s -- banning and disconnecting", sp)
 			sp.server.BanPeer(sp)
 			sp.Disconnect()
 			return true
@@ -1330,24 +1332,28 @@ func (sp *serverPeer) OnNotFound(p *peer.Peer, msg *wire.MsgNotFound) {
 		case wire.InvTypeWitnessTx:
 			numTxns++
 		default:
-			peerLog.Debugf("Invalid inv type '%d' in notfound message from %s",
-				inv.Type, sp)
+			peerLog.Infof("Invalid inv type '%d' in NotFound message from %s. Disconnecting...", inv.Type, sp)
 			sp.Disconnect()
 			return
 		}
 	}
 	if numBlocks > 0 {
 		blockStr := pickNoun(uint64(numBlocks), "block", "blocks")
-		reason := fmt.Sprintf("%d %v not found", numBlocks, blockStr)
-		if sp.addBanScore(20*numBlocks, 0, reason) {
-			return
+		reason := fmt.Sprintf("%d %v not found on %s", numBlocks, blockStr, sp)
+		if sp.addBanScore(20, 0, reason) {
+			return // once they fail to return us five block requests they're gone for good
 		}
 	}
 	if numTxns > 0 {
-		txStr := pickNoun(uint64(numTxns), "transaction", "transactions")
-		reason := fmt.Sprintf("%d %v not found", numBlocks, txStr)
-		if sp.addBanScore(0, 10*numTxns, reason) {
-			return
+		// This is an expected situation if transactions in the mempool make it into a block before
+		// this node knows about said block. We don't want to ban them for that alone
+		peerLog.Debugf("%d transactions not found on %s", numTxns, sp)
+		if numBlocks+numTxns < wire.MaxInvPerMsg { // if our message is full then it is likely followed by another one that isn't
+			txStr := pickNoun(uint64(numTxns), "transaction", "transactions")
+			reason := fmt.Sprintf("%d %v not found on %s", numTxns, txStr, sp)
+			if sp.addBanScore(0, 20, reason) {
+				return // if they fail us five times in one minute, they're gone -- hitting them at new-block should be rare
+			}
 		}
 	}
 
@@ -2727,6 +2733,7 @@ func newServer(listenAddrs, agentBlacklist, agentWhitelist []string,
 
 	claimTrieCfg := claimtrieconfig.DefaultConfig
 	claimTrieCfg.DataDir = cfg.DataDir
+	claimTrieCfg.Interrupt = interrupt
 
 	var ct *claimtrie.ClaimTrie