[Asterisk-code-review] res pjsip pubsub: Correctly implement persisted subscriptions (asterisk[13])

[George Joseph]

Hello Mark Michelson, Richard Mudgett, Anonymous Coward #1000019, Joshua Colp,

I'd like you to reexamine a change.  Please visit

    https://gerrit.asterisk.org/4916

to look at the new patch set (#4).

Change subject: res_pjsip_pubsub:  Correctly implement persisted subscriptions
......................................................................

res_pjsip_pubsub:  Correctly implement persisted subscriptions

This patch fixes 2 original issues and more that those 2 exposed.

* When we send a NOTIFY, and the client either doesn't respond or
  responds with a non OK, pjproject only calls our
  pubsub_on_evsub_state callback, no others.  Since
  pubsub_on_evsub_state (which does the sub_tree cleanup) does not
  expect to be called back without the other callbacks being called
  first, it just returns leaving the sub_tree orphaned.  Now
  pubsub_on_evsub_state checks the event for PJSIP_EVENT_TSX_STATE
  which is what pjproject will set to tell us that it was the
  transaction that timed out or failed and not the subscription
  itself timing our or being terminated by the client. If is
  TSX_STATE, pubsub_on_evsub_state now does the proper cleanup
  regardless of the state of the subscription.

* When a client renews a subscription, we don't update the
  persisted subscription with the new expires timestamp.  This causes
  subscription_persistence_recreate to prune the subscription if/when
  asterisk restarts.  Now, pubsub_on_rx_refresh calls
  subscription_persistence_update to apply the new expires timestamp.
  This exposed other issues however...

* When creating a dialog from rdata (which sub_persistence_recreate
  does from the packet buffer) there must NOT be a tag on the To
  header (which there will be when a client refreshes a
  subscription).  If there is one, pjsip_dlg_create_uas will fail.
  To address this, subscription_persistence_update now accepts a flag
  that indicates that the original packet buffer must not be updated.
  New subscribes don't set the flag and renews do.  This makes sure
  that when the rdata is recreated on asterisk startup, it's done
  from the original subscribe packet which won't have the tag on To.

* The acts of creating a dialog and evsub by themselves when
  recreating a subscription does NOT restart pjproject's subscription
  timer.  The result was that even if we did correctly recreate the
  subscription, we never removed it if the client happened to go away
  or send a non-OK response to a NOTIFY.  However, there is no
  pjproject function exposed to just set the timer on an evsub that
  wasn't created by an incoming subscribe request.  To address this,
  a new pjproject evsub API was created (pjsip_evsub_set_uas_timeout)
  and a patch sent to Teluu, which was accepted.  Since this requires
  an updated pjproject, we create our own timer using
  ast_sip_schedule_task if the new API isn't available such as when
  the user isn't using the bundled pjproject.

While addressing these issues, additional debugging was added and
some existing messages made more useful.  A few formatting changes
were also made to 'pjsip show scheduled tasks' to make displaying
the subscription timers a little more friendly.

ASTERISK-26696
ASTERISK-26756

Change-Id: I8c605fc1e3923f466a74db087d5ab6f90abce68e
---
M configure
M configure.ac
M include/asterisk/autoconfig.h.in
M res/res_pjsip/pjsip_scheduler.c
M res/res_pjsip_exten_state.c
M res/res_pjsip_pubsub.c
M third-party/pjproject/configure.m4
A third-party/pjproject/patches/0010-evsub-Add-pjsip_evsub_set_uas_timeout.patch
8 files changed, 380 insertions(+), 50 deletions(-)


  git pull ssh://gerrit.asterisk.org:29418/asterisk refs/changes/16/4916/4
-- 
To view, visit https://gerrit.asterisk.org/4916
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Gerrit-MessageType: newpatchset
Gerrit-Change-Id: I8c605fc1e3923f466a74db087d5ab6f90abce68e
Gerrit-PatchSet: 4
Gerrit-Project: asterisk
Gerrit-Branch: 13
Gerrit-Owner: George Joseph <gjoseph at digium.com>
Gerrit-Reviewer: Anonymous Coward #1000019
Gerrit-Reviewer: George Joseph <gjoseph at digium.com>
Gerrit-Reviewer: Joshua Colp <jcolp at digium.com>
Gerrit-Reviewer: Mark Michelson <mmichelson at digium.com>
Gerrit-Reviewer: Richard Mudgett <rmudgett at digium.com>