[Serusers] call log and accounting for forwarded and referred calls

[Richard]

>  >  In
>  > this example, B (an IP phone) sets his phone forwarding to C which is a
> long
>  > distance number. A is from PSTN. When A makes a call to B, B sends 302
> to
>  > the PSTN gateway. The gateway forwards the call to ser which routes it
> back
>  > to C via the PSTN gatway. So in ser's call log, I see a call from A to
> C.
>  > Apparently I can't charge A or C. Only B is in my domain. But B is not
> even
>  > in the second call log. In my understanding, if B sets the forward
> setting
>  > on his phone to a toll number, he should be the one paying the bill.
> 
> regarding pstn gws, i recommend that you turn off 302 processing, since
> otherwise your gw may end up paying for the forwarded (expensive) leg of
> the call, since, as you say, you cannot charge the PSTN caller.
> 


Since logging and accounting is a problem, I want to only allow local
numbers in the forward field. Is there any function available to match and
modify the contact field. For example, if it is "Contact:
<sip:18085551212 at mydomain.com>", I should change it to "Contact:
vm+(original-callee-number)@mydomain.com" which goes to voicemail. Are
search() and append_urihf() good for this?

I think the same issue applies to REFER. However I won't be able to disallow
a toll call on REFER. It is possible a secretary makes a toll call, then
REFREs to the boss. So I have to find some way to log and account this.

Thanks,
Richard