Get real channel of a DAHDI call.

Starting with Asterisk v1.8, the DAHDI channel name format was changed for
ISDN calls to: DAHDI/i<span>/<number>[:<subaddress>]-<sequence-number>

There were several reasons that the channel name had to change.

1) Call completion requires a device state for ISDN phones.  The generic
device state uses the channel name.

2) Calls do not necessarily have B channels.  Calls placed on hold by an
ISDN phone do not have B channels.

3) The B channel a call initially requests may not be the B channel the
call ultimately uses.  Changes to the internal implementation of the
Asterisk master channel list caused deadlock problems for chan_dahdi if it
needed to change the channel name.  Chan_dahdi no longer changes the
channel name.

4) DTMF attended transfers now work with ISDN phones because the channel
name is "dialable" like the chan_sip channel names.

For various reasons, some people need to know which B channel a DAHDI call
is using.

* Added CHANNEL(dahdi_span), CHANNEL(dahdi_channel), and
CHANNEL(dahdi_type) so the dialplan can determine the B channel currently
in use by the channel.  Use CHANNEL(no_media_path) to determine if the
channel even has a B channel.

* Added AMI event DAHDIChannel to associate a DAHDI channel with an
Asterisk channel so AMI applications can passively determine the B channel
currently in use.  Calls with "no-media" as the DAHDIChannel do not have
an associated B channel.  No-media calls are either on hold or
call-waiting.

(closes issue #17683)
Reported by: mrwho
Tested by: rmudgett

(closes issue #18603)
Reported by: arjankroon
Patches:
      issue17683_18603_v1.8_v2.patch uploaded by rmudgett (license 664)
Tested by: stever28, rmudgett


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@309445 65c4cc65-6c06-0410-ace0-fbb531ad65f3
This commit is contained in:
Richard Mudgett
2011-03-04 15:22:04 +00:00
parent d5e1774082
commit 5b9f9f78ca
5 changed files with 147 additions and 0 deletions

View File

@@ -913,6 +913,24 @@ static void sig_pri_open_media(struct sig_pri_chan *p)
}
}
/*!
* \internal
* \brief Post an AMI B channel association event.
* \since 1.8
*
* \param p Channel private control structure.
*
* \note Assumes the private and owner are locked.
*
* \return Nothing
*/
static void sig_pri_ami_channel_event(struct sig_pri_chan *p)
{
if (p->calls->ami_channel_event) {
p->calls->ami_channel_event(p->chan_pvt, p->owner);
}
}
struct ast_channel *sig_pri_request(struct sig_pri_chan *p, enum sig_pri_law law, const struct ast_channel *requestor, int transfercapability)
{
struct ast_channel *ast;
@@ -1291,6 +1309,10 @@ static int pri_fixup_principle(struct sig_pri_span *pri, int principle, q931_cal
sig_pri_open_media(new_chan);
}
if (new_chan->owner) {
sig_pri_ami_channel_event(new_chan);
}
sig_pri_unlock_private(old_chan);
if (new_chan->owner) {
ast_channel_unlock(new_chan->owner);