[asterisk-dev] SipAddHeader and SIP REFER

[Kirill Katsnelson]

Additional headers from SIPAddHeader are not added to the REFER packet. 
This is a practical case for us now.

The machinery is all there, so it seems an easy fix. I do not know, 
however, what is the best way to implement the functionality so it might 
be useful to everyone. I see the following options:

1. Just always add the headers if set in the dialplan, just like it is 
done with the INVITE.

2. Create an option in sip.conf that would enable behavior (1), default off.

3. Extend Transfer() application with a flag argument, and a flag to 
enable sending the extra headers.

4. Do not release a patch. Nobody would be interested anyway.

I would be all for the option (1); however, it might have regression 
implication, if someone's implementation depends on not sending the 
extra headers. Cannot think of an RFC compliant SIP implementation that 
would be really broken, but can cause e. g. unintended information leak.

(2) seems a good compromise in this case, while (3)seems overcomplicated 
to me.

What do you think?

  -kkm