[OpenSIPS-Users] Detecting CANCEL arriving at same time as 200 OK

[John Quick]

Using OpenSIPS v1.9 as a routing Proxy for a dialler service, there are a
few calls each day where the dialler sends CANCEL at almost the same time as
the called destination responds with 200 OK. In fact, the problem cases are
when "200 OK" arrives milliseconds before the CANCEL.

I am trying to find a way - when handling the CANCEL request - to detect if
a "200 OK" has already been received. I tried setting a dialog flag in the
onreply_route then checking that flag in the main route when $rm ==CANCEL,
but this does not work. Is there any other way, such as using
t_check_trans(), to reliably identify the few calls where this sequence
occurs?

By the way, the reason I need to detect these cases is because it breaks the
Radius accounts reporting. These calls send start when the call starts, but
no stop when the call ends.

John Quick
Smartvox Limited
Web: www.smartvox.co.uk