Hello,

the sip3.txt contains just a SIP message, nothing really special about it. 😊

Cheers,

Henning

From: Patrick Wakano <pwak...@gmail.com>
Sent: Mittwoch, 3. Mai 2023 08:02
To: mico...@gmail.com
Cc: Kamailio (SER) - Users Mailing List <sr-users@lists.kamailio.org>
Subject: [SR-Users] Re: Clarification of 'return false' behaviour

Thanks Henning and Daniel for taking the time to check this out!
I will double check my env but anyway will review my script and follow Daniel's 
recommendations!
Hennig, would you be able to disclose the contents of your /root/sip3.txt file? 
It really got my interest in this nc usage!
Appreciate your replies!

Kind regards,
Patrick

On Tue, 2 May 2023 at 18:10, Daniel-Constantin Mierla 
<mico...@gmail.com<mailto:mico...@gmail.com>> wrote:

Hello,

indeed, it is somehow confusing, because in terms of evaluating the return code 
in logical expression, 'false' means the return code was negative and 'true' 
means it was positve.

Then the core keywords 'true' and 'false' are just aliases to 1 and 0 for use 
with core parameters, but their meaning is not related to logical evaluation of 
function's return code.

Someone decided like 20 years ago to have this kind of logical evaluation and 
it continued to be like that till now.

There was a regression at some point when return 0 was no longer exiting, being 
fixed at some point. One may notice the behaviour change if run same config 
before and after.

In general is not good to just return the value from execution of a function, 
but evaluate to true or false and return explicitly own values. Instead of

return x()

do:

if(x()) {

return 1;

} else {

return -1;

}

Cheers,
Daniel
On 01.05.23 01:10, Patrick Wakano wrote:
Thanks very much for the clarification Daniel! Appreciate it!
However it does seem that some modules have inconsistencies with return values 
now. So, for instance, the is_ip_rfc918() says it will return true or false 
(https://kamailio.org/docs/modules/5.6.x/modules/ipops.html#ipops.f.is_ip_rfc1918
 - most functions of this module return true or false) and then when used 
directly with return, it terminates execution. Based on your explanation, it 
shouldn't return true or false, but likely -1 or 1, which would never be 
considered 'return 0'
Also, the below code works in version 5.4, but terminates execution in version 
5.6, so are you aware of changes in this behaviour in version 5.5 or 5.6 
(before the 5.7 changes you mentioned)?
route[is_src_private]
{
     return is_ip_rfc1918("$si");
}
request_route
{
...
        if (route(is_src_private)) {
                xlog("L_NOTICE", "SRC private\n");
        } else {
                xlog("L_NOTICE", "SRC public\n");
        }
...
}

Best regards!
Patrick

On Fri, 28 Apr 2023 at 16:29, Daniel-Constantin Mierla 
<mico...@gmail.com<mailto:mico...@gmail.com>> wrote:
Hello,

false is 0 and it was actually designed for setting global parameters, not for 
use as comparison with functions return code or as parameter for return from 
route blocks. Like:

log_stderror = false

The grammar of the language defines a coupe of token variants for same purpose:


   YES         "yes"|"true"|"on"|"enable"
   NO          "no"|"false"|"off"|"disable"

Where YES is replaced by 1 and NO is replaced by 0:

   <INITIAL>{YES}          { count(); yylval.intval=1;
                               yy_number_str=yytext; return NUMBER; }
   <INITIAL>{NO}           { count(); yylval.intval=0;
                               yy_number_str=yytext; return NUMBER; }

In the devel version (upcoming 5.7.0), the evaluation of return mode can be 
controlled by core parameter return_mode, allowing to switch to a more 
"standard" mode, similar to other scripting languages -- see:

  - https://www.kamailio.org/wikidocs/cookbooks/devel/core/#return_mode

Cheers,
Daniel

On 28.04.23 08:14, Patrick Wakano wrote:
Hi list,
Hope you are all well!

I'm using Kamailio version 5.6.4 (installed from the repo 
rpm.kamailio.org/centos/7<http://rpm.kamailio.org/centos/7>) and noticed that 
every route that uses "return false" is exiting the script, instead of 
returning.... This was not the case on version 5.4.6 as the same script is 
running fine.....
From this page 
https://www.kamailio.org/wikidocs/tutorials/faq/main/#how-is-the-function-return-code-evaluated,
 I would think that when a route returns false, it would return -1 and not stop 
execution, since negative is equal to false, but it is actually stopping (same 
as return 0)...
So, as an example, this test code doesn't work as expected. In case the source 
is a public IP, the script doesn't print the "SRC public" it just exits and 
then of course every other logic meant to be done is not executed....

route[is_src_private]
{
        if (is_ip_rfc1918("$si")) {
                return true;
        }
        return false;
        #return is_ip_rfc1918("$si"); # this doesn't work too in case the $si 
is a public IP
}
request_route
{
...
        if (route(is_src_private)) {
                xlog("L_NOTICE", "SRC private\n");
        } else {
                xlog("L_NOTICE", "SRC public\n");
        }
...
}
If is_src_private is changed to return -1 instead of false, then it all works 
fine.

Also, I noticed that the following code will print "TEST: 0" in case the $si is 
public and then stop execution. So looks like false is really being converted 
to 0, but I guess that's unexpected... anyway apologies if I'm missing 
something obvious....
route[is_src_private]
{
        $var(t) = false;
        if (is_ip_rfc1918("$si")) {
                $var(t) = true;
        }
        xlog("L_ERR", "TEST: $var(t)\n");
        return $var(t);
}

I could not find a recent ticket or email related to this situation and I've 
already spent hours trying to understand what is the logic/problem here, so 
would anyone have been across a similar case that could provide some insight 
and clarify what is the expected behaviour of the false usage (and boolean in 
general if possible)?

Thank you,
Kind regards,
Patrick Wakano


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--

Daniel-Constantin Mierla -- www.asipto.com<http://www.asipto.com>

www.twitter.com/miconda<http://www.twitter.com/miconda> -- 
www.linkedin.com/in/miconda<http://www.linkedin.com/in/miconda>

Kamailio World Conference - June 5-7, 2023 - 
www.kamailioworld.com<http://www.kamailioworld.com>

--

Daniel-Constantin Mierla -- www.asipto.com<http://www.asipto.com>

www.twitter.com/miconda<http://www.twitter.com/miconda> -- 
www.linkedin.com/in/miconda<http://www.linkedin.com/in/miconda>

Kamailio World Conference - June 5-7, 2023 - 
www.kamailioworld.com<http://www.kamailioworld.com>
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