Add inactivity ping

kylecarbs · kylecarbs · commit cdecac151009 · 2022-09-01T03:51:13.000Z
diff --git a/tailnet/conn.go b/tailnet/conn.go
@@ -302,7 +302,17 @@ func (c *Conn) UpdateNodes(nodes []*Node) error {
 	for _, peer := range c.netMap.Peers {
 		if peerStatus, ok := status.Peer[peer.Key]; ok {
 			// Clear out inactive connections!
+			// If the connection hasn't been written to in a while, we manually
+			// send a ping to ensure it's still alive.
 			if !peerStatus.Active {
+				c.Ping(peer.Addresses[0].Addr(), tailcfg.PingDisco, func(pr *ipnstate.PingResult) {
+					if pr.Err != "" {
+						// If an error happened during ping (like no route to host),
+						// we omit it from being added to the map, and go on!
+						return
+					}
+					peerMap[peer.ID] = peer
+				})
 				continue
 			}
 		}
