I have to contact through a SIP trunk a device without SDP.
The device answers with a 180 ringing message followed by a 183 Session Progress (still without SDP)
Finally the device send a 487 Request Terminated.
As I found on the net, in case of a 183 Session Progress without SDP Asterisk replaces it by 180 Ringing.
My problem is that the device sends in the 183 Session Progress message a custom header which is required for my application.
It seems Asterisk doesn’t copy all headers from the origination message.
Which piece of code should I modify in the chan_sip.c file to modify the behavior?
I am not a C developer …
Thanks for your time.