ua,call: add API for rejecting incoming call

[cspiel1]

Implements: baresip/baresip#3207

config

The redirect module has to be loaded first, at least before module menu because it stops the UA_EVENT_SIPSESS_CONN event if a redirect is set by the user.

# Application Modules

module_app		redirect.so
...
module_app		menu.so

[cspiel1]

Did some basic tests.

[cspiel1]

@zucher please could you test this? Does it fit to your needs?

[zucher]

@cspiel1 sure, thank you, I take a look tomorrow.

[zucher]

I just take a look shortly on the code, as static setting it's seems fine, but in my currently wish , I expect to manage the hangup rejection on demand dynamically according to the incoming number, so in such case static configuration doesn't fit.
The dynamic rejection depends on external CRM/DB, so managing asynchronously on event ( tcp /mqtt,dbus/...) seems the most appropriated.

[cspiel1]

This sounds useful in general. So, I'll try to find a solution for this. With an async query to the app currently I see the problem, that the answer has to come very quickly from the app in order to avoid sending of SIP retries. But I'll check the details for the timing.

[zucher]

I manage on my side some test to reject on SIP RINGING, and it's working, so the delay seems not an issue, and the divert on microsip use also the same method on ringing state.

[zucher]

but this means not treating the rejection/hhangup at application side but directly into baresip lib due to session depends, not accessible ouside the lib.

[cspiel1]

Working on an API function:

void call_reject(struct call *call, uint16_t scode, const char *reason, const char *fmt, ...);

/* usage example */
	call_reject(call, scode, reason,
	      "Contact: <%r>%s\r\n"
	      "Diversion: <%s>%r\r\n"
	      "Content-Length: 0\r\n\r\n",
	      &params.contact,
	      expstr,
	      account_aor(ua_account(ua)),
	      &params.divparams);

Edit: Maybe the name will change.

[zucher]

That's sound good, I'm working with callid's to be able to manage multiple incoming calls at a time. The integration of this function into an app becomes simpler
👍

[cspiel1]

Here is what we need in baresip core: baresip/baresip#3228.

The commit that follows add a new command the is able to reject a call with given Contact, expiry, Diversion parameters, scode and reason.

I have to change the title of this PR in order to switch to the right baresip branch.

[zucher]

@cspiel1 , Thank you that's working very fine !

[cspiel1]

You're welcome!

In order to keep menu/dynamic_menu.c in the baresip repo small and simple I suggest to keep the command call_redirect here in this baresip-apps module. Until otherwise requested.

I suggest also to keep the other commands uaredirect_add, uaredirect_clear and uaredirect_debug. They provide the early reject of a SIP INVITE. With early I mean that no call object, or SIP session/dialog is allocated and ringing is not started.