How to get Answered number / answered CLID in case of simultaneous calls forwarding in Asterisk?

Question

I have a problem, already 20 hours on the topic, but can't solve it. The case that I can't bill the call because I can't get an exact CLID of an answered number in case of simultaneous call forwarding in Asterisk. ${CDR(src)}, ${CDR(dst)} do not help here.

I call from PSTN +79000000000 to DID +78120000000 and call is landed to our Asterisk. On asterisk, via the same trunk the call is being forwarded to another PSTN +74950000000 and answered there. On call completion in CDR we can see:

src: 79000000000
dst: 78120000000

and no info about the last 78120000000 -> 74950000000 call

I can use CDR variable to store 74950000000 in before calling Dial application:

Set(CDR(fwd)=74950000000);
Dial(SIP/78120000000/74950000000);

then in CDR on call completion we can see:

src: 79000000000
dst: 78120000000
fwd: 74950000000

and that's okay, because I can limit max call duration before Dial and bill the call after Hangup. All thanks to known fwd.

sip.conf

[78120000000]
name=78120000000
type=peer
host=sip.provider.com

extensions.ael

context sequential {
   _.=> {
       Set(CDR(fwd)=74950000000);
       Dial(SIP/78120000000/74950000000);
       Hangup();
    }
    h => {
       Set(BILL_THE_CALL=${ODBC_BILL_THE_CALL()});
       // billing is easily executed thanks to logged fwd in CDR
    }
  }

But in case of simultaneous call forwarding this is impossible:

  context simultaneous {
   _.=> {
       // can't set fwd before call completion, because don't know 
       // if my_cell_phone or softphone will answer
       // my_cell_phone costs 5 cents/min, softfone is free of charge
       Dial(SIP/78120000000/74950000000&SIP/softphone);
       Hangup();
   }
   h => {
       Set(BILL_THE_CALL=${ODBC_BILL_THE_CALL()});
       // billing is impossible because fwd is not logged to CDR
   }
 }

On call completion in CDR we can see the same, as for sequential case, without fwd:

src: 79000000000
dst: 78120000000

and no info about the last 78120000000 -> 74950000000 or to softphone

So, do you know any way to get that Answered username, answered number, answered CLID, whatsoever in order to be able to bill the call?

http://www.voip-info.org/wiki/view/Asterisk+variables

http://www.voip-info.org/wiki/view/Asterisk+func+channel

etc. links contain nothing helpful for me.

On the call I can also apply

sip show channel faf7767642

and see channel Username, Origination uri, etc that contain my fwd number, but I can't get them from there with dialplan. But when I call:

NoOp(${CHANNEL(username)});

it just shows nothing. Have any ideas? Can't believe I missed something obvious. Thank you!

Answer 1

Yes, it worked thanks to M(x) execution during Dial() command with Set(GLOBAL(var)=${CHANNEL(peername)}) inside that macro-x context.

context macro-give-me-answered-clid {
    _. => {
        Set(GLOBAL(simultaneous_call_answered_peer)=${CHANNEL(peername)});
    }
}

context simultaneous {
   _.=> {
     // can't set fwd before call completion, because don't know 
     // if my_cell_phone or softphone will answer
     // my_cell_phone costs 5 cents/min, softfone is free of charge
     Dial(SIP/78120000000/74950000000&SIP/softphone,,M(give-me-answered-clid));
     Hangup();
   }

   h => {
     Set(CDR(fwd)=${simultaneous_call_answered_peer})
     Set(BILL_THE_CALL=${ODBC_BILL_THE_CALL()});
     // billing is ok because fwd is now logged to CDR
   }
} 

Maybe not nice, maybe yet stupid, but works and I am happy with that for now. Thank you so much for your help, artheops!

As to developing complex solutions without expert skills, that's a perfect Guy Ritchie's answer on that:

The only way to get smarter is by playing smarter opponent.

(c) Revolver, 2005. That's THE ONLY way to get expert.