Stasis: Fix StasisStart/End order and missing events

This corrects several bugs that currently exist in the stasis
application code.

* After a masquerade, the resulting channels have channel topics that
  do not match their uniqueids
** Masquerades now swap channel topics appropriately
* StasisStart and StasisEnd messages are leaked to observer
  applications due to being published on channel topics
** StasisStart and StasisEnd publishing is now properly restricted
   to controlling apps via app topics
* Race conditions exist where StasisStart and StasisEnd messages due to
  a masquerade may be received out of order due to being published on
  different topics
** These messages are now published directly on the app topic so this
   is now a non-issue
* StasisEnds are sometimes missing when sent due to masquerades and
  bridge swaps into and out of Stasis()
** This was due to StasisEnd processing adjusting message-sent flags
   after Stasis() had already exited and Stasis() had been re-entered
** This was corrected by adjusting these flags prior to sending the
   message while the initial Stasis() application was still shutting
   down

Review: https://reviewboard.asterisk.org/r/4213/
ASTERISK-24537 #close
Reported by: Matt DiMeo
........

Merged revisions 429061 from http://svn.asterisk.org/svn/asterisk/branches/12
........

Merged revisions 429062 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@429063 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 9 insertions, 0 deletions

diff --git a/main/channel_internal_api.c b/main/channel_internal_api.c
index c62812ea7..624bdd1cb 100644
--- a/main/channel_internal_api.c
+++ b/main/channel_internal_api.c
@@ -1534,6 +1534,15 @@ void ast_channel_internal_swap_uniqueid_and_linkedid(struct ast_channel *a, stru
 	b->linkedid = temp;
 }
 
+void ast_channel_internal_swap_topics(struct ast_channel *a, struct ast_channel *b)
+{
+	struct stasis_cp_single *temp;
+
+	temp = a->topics;
+	a->topics = b->topics;
+	b->topics = temp;
+}
+
 void ast_channel_internal_set_fake_ids(struct ast_channel *chan, const char *uniqueid, const char *linkedid)
 {
 	ast_copy_string(chan->uniqueid.unique_id, uniqueid, sizeof(chan->uniqueid.unique_id));