As the session manager handles messages sent to unavailable resources
just like messages sent to bare JIDs, mod_carboncopy must do that, too.
That is, forward them only to those carbon-copy-enabled resources that
don't have a top priority, in order to avoid duplicates.
On connection timeout, drop any messages that were forwarded by some
encapsulating protocol, such as XEP-0280 carbon copies or XEP-0313
archive messages. Bouncing or resending them could easily lead to
unexpected results.
Implement the optional session resumption feature described in XEP-0198.
A client that supports this feature may now resume the previous session
(within a configurable number of seconds) if the connection was lost.
During resumption, ejabberd will retransmit any stanzas that hadn't been
acknowledged by the client.
Implement partial support for XEP-0198: Stream Management. After
successful negotiation of this feature, the server requests an ACK for
each stanza transmitted to the client and responds to ACK requests
issued by the client. On session termination, the server re-routes any
unacknowledged stanzas. The length of the pending queue can be limited
by setting the "max_ack_queue" option to some integer value (default:
500). XEP-0198 support can be disabled entirely by setting the
"stream_management" option to false (default: true).
So far, stream management is implemented only for c2s connections, and
the optional stream resumption feature also described in XEP-0198 is not
(yet) supported.
This addition was originally based on a patch provided by Magnus Henoch
and updated by Grzegorz Grasza. Their code implements an early draft of
XEP-0198 for some previous version of ejabberd. It has since been
rewritten almost entirely.
Fix configure's --{enable,disable}-transient_supervisors option: Make
sure it's enabled with --enable and disabled with --disable, not the
other way round. This also makes --disable the default setting, as
documented.
