LDAP_UNAVAILABLE signals "the server is shutting down or a subsystem
necessary to complete the operation is offline", so intelligent clients
tend to infer the connection will not be usable any more, which is not
the case here.

Reuse the connection walking facility in timeout management.

Trying to abandon an operation does not automatically make it completed,
it might have failed already but we're just racing to reach the client
to record that.

During response processing, an upstream connection could be marked ready
after a different bind had already been allocated to it, thus allowing
two binds to be in progress on the same connection.

Ondřej Kuzník authored Dec 13, 2017 and Ondřej Kuzník committed Nov 17, 2020

Introduces pinned operations. When SASL bind finishes, we might still
have to maintain a link between the client an an upstream for future
bind operations if we got a SASL Bind in Progress result code. We zero
out the msgids and remember a server-unique identifer on the client and
the relevant operation that lets us retrieve that link again. This
operation is reclaimed just like anything else when connections drop.

Hopefully, this should work for LDAP TXN and VC Exop support with SASL
later as well since it allows for many-to-many links to exist.

Ondřej Kuzník authored Jun 27, 2017 and Ondřej Kuzník committed Nov 17, 2020

Stats now logs all operations, stats2 additionally intermediate messages
(search entries).

Ondřej Kuzník authored Jun 27, 2017 and Ondřej Kuzník committed Nov 17, 2020

If we can't find an upstream, we keep the client around, so it needs to
be unblocked.