From: Matt Joiner <anacrolix@gmail.com>
Date: Thu, 10 Dec 2020 00:13:27 +0000 (+1100)
Subject: Don't send keepalives if a connection isn't useful to us
X-Git-Tag: v1.19.0~2
X-Git-Url: http://www.git.stargrave.org/?a=commitdiff_plain;h=de964db3c2ebdf439722c23f797a78c43fd8f6c2;p=btrtrc.git

Don't send keepalives if a connection isn't useful to us

This might help break the situation where anacrolix/torrent Clients that are connected to each other never release a connection until there's new connections that look more promising.
---

diff --git a/peerconn.go b/peerconn.go
index 633e54ce..e333d213 100644
--- a/peerconn.go
+++ b/peerconn.go
@@ -663,7 +663,7 @@ func (cn *PeerConn) writer(keepAliveTimeout time.Duration) {
 		if cn.writeBuffer.Len() == 0 {
 			cn.fillWriteBuffer()
 		}
-		if cn.writeBuffer.Len() == 0 && time.Since(lastWrite) >= keepAliveTimeout {
+		if cn.writeBuffer.Len() == 0 && time.Since(lastWrite) >= keepAliveTimeout && cn.useful() {
 			cn.writeBuffer.Write(pp.Message{Keepalive: true}.MustMarshalBinary())
 			postedKeepalives.Add(1)
 		}