[SR-Users] Strange behavior for unregister() function. Wrong docs? Bug?

[Daniel-Constantin Mierla]

Hello,

that is a "known hack" to go around the route block type restrictions
for functions.

The purpose of the restrictions is to limit the usage in the blocks
where the developer intended to allow the function to be used, like
she/he tested for those route blocks or thought it is enough there and
didn't analyze the effects when using in other route block types.

However, many functions are just safe to use in other route block types
than those imposed by the developer.

Probably the unregister() is safe in onreply block, because it doesn't
need to generate a reply or use information from request URI.

Cheers,
Daniel

On 13.08.19 07:28, Joel Serrano wrote:
> Forgot to add:
>
> root at csbc01:~# kamailio -V
> version: kamailio 5.3.0-dev7 (x86_64/linux)
> flags: STATS: Off, USE_TCP, USE_TLS, USE_SCTP, TLS_HOOKS,
> USE_RAW_SOCKS, DISABLE_NAGLE, USE_MCAST, DNS_IP_HACK, SHM_MMAP,
> PKG_MALLOC, Q_MALLOC, F_MALLOC, TLSF_MALLOC, DBG_SR_MEMORY, USE_FUTEX,
> FAST_LOCK-ADAPTIVE_WAIT, USE_DNS_CACHE, USE_DNS_FAILOVER, USE_NAPTR,
> USE_DST_BLACKLIST, HAVE_RESOLV_RES
> ADAPTIVE_WAIT_LOOPS 1024, MAX_RECV_BUFFER_SIZE 262144, MAX_URI_SIZE
> 1024, BUF_SIZE 65535, DEFAULT PKG_SIZE 8MB
> poll method support: poll, epoll_lt, epoll_et, sigio_rt, select.
> id: unknown
> compiled with gcc 8.3.0
> root at csbc01:~#
>
>
>
> On Mon, Aug 12, 2019 at 2:13 PM Joel Serrano <joel at textplus.com
> <mailto:joel at textplus.com>> wrote:
>
>     Hello, 
>
>     I'm playing around with the unregister() function from the
>     registrar module:
>
>     https://www.kamailio.org/docs/modules/devel/modules/registrar.html#registrar.f.unregister
>
>     Docs say that that it can be used in REQUEST_ROUTE or FAILURE_ROUTE.
>
>     I needed it in REPLY_ROUTE, and before reading the docs I tried it
>     and got this error:
>
>     Aug 12 15:52:44 csbc01 kamailio: CRITICAL: <core>
>     [core/cfg.y:3526]: yyerror_at(): parse error in config file
>     /etc/kamailio/csbc/reply_routes.cfg, line 27, column 71: Command
>     cannot be used in the block#012
>     Aug 12 15:52:44 csbc01 kamailio[12737]: ERROR: bad config file (1
>     errors)
>
>     But, I have this working on another setup, I compared, and my
>     difference is that I'm running unregister() inside a route, and
>     calling that route from reply_route, and that works (and by works,
>     I mean it also does what it is supposed to do, which is unregister
>     the AoR).
>
>     So this doesn't work:
>
>     ...
>     onreply_route[MANAGE_REG_REPLY] {
>          if(status=~"2[0-9][0-9]") {
>              if(($sel(contact.expires)==0) || ($hdr(Expires)==0)){
>                 if (unregister("location",
>     "$sht(sipserver=>$fU::contact)")) {
>                     xlog("L_NOTICE", "[usrloc] removed user location\n");
>                 }
>                 route(DEL_SIPSERVER);
>     }
>     ...
>
>     But this works:
>
>     ...
>     onreply_route[MANAGE_REG_REPLY] {
>          if(status=~"2[0-9][0-9]") {
>              if(($sel(contact.expires)==0) || ($hdr(Expires)==0)){
>                 route(UNREG_CUSTOMER);
>                 route(DEL_SIPSERVER);
>     }
>     ...
>
>     ...
>     route[UNREG_CUSTOMER] {
>                 if (unregister("location",
>     "$sht(sipserver=>$fU::contact)")) {
>                     xlog("L_NOTICE", "[usrloc] removed user location\n");
>                 }
>     }
>     ...
>
>
>
>     So I'm in no-mans-land right now, docs say it's not allowed in
>     REPLY_ROUTE, and if I try it it will fail, but if I try it inside
>     a route, it woks (hack?).
>
>     What is the correct approach here? Should unregister() be valid in
>     reply_route (like other similar functions, for example: save())
>     and therefor docs should be updated and the error in the logs
>     should also be updated, or if it's really not supported, shouldn't
>     Kamailio not let me use it anywhere that a ends up being called
>     from reply_route?
>
>     I hope I have explained myself correctly. As always, please let me
>     know if this should be a GH issue instead and I'll happily create it.
>
>     Thanks, 
>     Joel.
>
>
>
>
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-- 
Daniel-Constantin Mierla -- www.asipto.com
www.twitter.com/miconda -- www.linkedin.com/in/miconda

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