BUG/MINOR: server: fix logic flaw in idle connection list management
With variable connection limits, it's not possible to accurately determine
whether the mux is still in use by comparing usage and max to be equal due
to the fact that one determines the capacity and the other one takes care
of the context. This can cause some connections to be dropped before they
reach their stream ID limit.
It seems it could also cause some connections to be terminated with
streams still alive if the limit was reduced to match the newly computed
avail_streams() value, though this cannot yet happen with existing muxes.
Instead let's switch to usage reports and simply check whether connections
are both unused and available before adding them to the idle list.
This should be backported to 1.9.
diff --git a/include/types/connection.h b/include/types/connection.h
index f11cfb5..96728b3 100644
--- a/include/types/connection.h
+++ b/include/types/connection.h
@@ -342,7 +342,7 @@
int (*subscribe)(struct conn_stream *cs, int event_type, void *param); /* Subscribe to events, such as "being able to send" */
int (*unsubscribe)(struct conn_stream *cs, int event_type, void *param); /* Unsubscribe to events */
int (*avail_streams)(struct connection *conn); /* Returns the number of streams still available for a connection */
- int (*max_streams)(struct connection *conn); /* Returns the max number of streams available for that connection. */
+ int (*used_streams)(struct connection *conn); /* Returns the number of streams in use on a connection. */
void (*destroy)(struct connection *conn); /* Let the mux know one of its users left, so it may have to disappear */
void (*reset)(struct connection *conn); /* Reset the mux, because we're re-trying to connect */
const struct cs_info *(*get_cs_info)(struct conn_stream *cs); /* Return info on the specified conn_stream or NULL if not defined */