Fix loss of MOH on an ISDN channel when parking a call for the second time.

Using the AMI redirect action to take an ISDN call out of a parking lot
causes the MOH state to get confused.  The redirect action does not take
the call off of hold.  When the call is subsequently parked again, the
call no longer hears MOH.

* Make chan_dahdi/sig_pri restart MOH on repeated AST_CONTROL_HOLD frames
if it is already in a state where it is supposed to be sending MOH.  The
MOH may have been stopped by other means.  (Such as killing the generator.)

This simple fix is done rather than making the AMI redirect action post an
AST_CONTROL_UNHOLD unconditionally when it redirects a channel and thus
potentially breaking something with an unexpected AST_CONTROL_UNHOLD.

(closes issue ABE-2873)
Patches:
      jira_abe_2873_c.3_bier.patch (license #5621) patch uploaded by rmudgett
........

Merged revisions 372521 from https://origsvn.digium.com/svn/asterisk/be/branches/C.3-bier

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/10@372522 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/sig_pri.c b/channels/sig_pri.c
index 6d95cf8453ebb654ab75a7e8a956c4b1869e8be0..ad8c31452075b6ddd09a744e3ed6880d1224756e 100644 (file)
--- a/channels/sig_pri.c
+++ b/channels/sig_pri.c
@@ -4686,6 +4686,12 @@ static enum sig_pri_moh_state sig_pri_moh_fsm_notify(struct ast_channel *chan, s
 
        next_state = pvt->moh_state;
        switch (event) {
+       case SIG_PRI_MOH_EVENT_HOLD:
+               if (strcasecmp(pvt->mohinterpret, "passthrough")) {
+                       /* Restart MOH in case it was stopped by other means. */
+                       ast_moh_start(chan, pvt->moh_suggested, pvt->mohinterpret);
+               }
+               break;
        case SIG_PRI_MOH_EVENT_UNHOLD:
                pri_notify(pvt->pri->pri, pvt->call, pvt->prioffset, PRI_NOTIFY_REMOTE_RETRIEVAL);
                /* Fall through */
@@ -4720,6 +4726,10 @@ static enum sig_pri_moh_state sig_pri_moh_fsm_moh(struct ast_channel *chan, stru
 
        next_state = pvt->moh_state;
        switch (event) {
+       case SIG_PRI_MOH_EVENT_HOLD:
+               /* Restart MOH in case it was stopped by other means. */
+               ast_moh_start(chan, pvt->moh_suggested, pvt->mohinterpret);
+               break;
        case SIG_PRI_MOH_EVENT_RESET:
        case SIG_PRI_MOH_EVENT_UNHOLD:
                ast_moh_stop(chan);