libp2p: idle timeout follows keepalive

1 files changed, 9 insertions, 1 deletions

diff --git a/src/transport/libp2p/mod.rs b/src/transport/libp2p/mod.rs
index a159280..3ebe7f6 100644
--- a/src/transport/libp2p/mod.rs
+++ b/src/transport/libp2p/mod.rs
@@ -128,8 +128,16 @@ const SLOW_SEND: Duration = Duration::from_millis(5);
 const MAX_MESSAGE: usize = 128 << 20;
 /// How long a connection may take to come up.
 const CONNECT_TIMEOUT: Duration = Duration::from_secs(10);
-/// A connection nobody uses is closed after this; neighbours keep theirs busy.
+/// A connection nobody uses is closed after this at least; neighbours keep theirs busy,
+/// with a keepalive within one and a half intervals (`PeerState::take_keepalive_due`),
+/// so a long interval lengthens it (`idle_timeout`).
 const IDLE_TIMEOUT: Duration = Duration::from_secs(300);
+
+/// How long a connection may idle before it is closed: `IDLE_TIMEOUT`, or three
+/// keepalive intervals if that is longer.
+fn idle_timeout(keepalive: Duration) -> Duration {
+    IDLE_TIMEOUT.max(keepalive * 3)
+}
 /// Addresses of one dial tried at once (libp2p's default: 8). Hole punching (`HolePunching`)
 /// dials every address both sides offer, where they listen (LAN, VPNs, public IPv6) and
 /// where others saw them, often more than 8, while the other side punches towards all of