[Kamailio-Devel] [Serdev] CVS:commitlog: sip_router/modules/tm t_cancel.c t_fwd.c t_reply.c t_reply.h t_suspend.c t_suspend.h tm.c tm_load.c tm_load.h

[Klaus Darilion]

Andrei Pelinescu-Onciul schrieb:
> [crossposting since this is of general interest]
> 
> On Nov 12, 2008 at 00:30, Klaus Darilion <klaus.mailinglists at pernau.at> wrote:
>> Hi Miklos!
>>
>> This sounds great. Can you make a sample function which uses the new 
>> feature?
> 
> We are thinking of doing a dns_prefetch module using this.
> The sip-router.cfg will look like:
> 
> route{
>     ...
>     dns_prefetch("uri", ROUTE_DNS_OK);
>     # end of script
> }
> 
> route[ROUTE_DNS_OK]{
>     if (dns_error){
>         ...
>     }
>     # continue normal processing
>     # the uri was resolved and is in the dns cache
>     ...
>     t_relay()
>     ...
> }

Ok. I see.


> However don't expect something quickly as everybody is quite busy and we
> would still need to write a dns resolver process pool (time consuming).

I still wonder if the DNS resolver in ser is really a good idea. For 
example if you take a look at bind, it is really mature and still they 
fix several issues with each release - and doing all the tricks to avoid 
cache poisoning and handling DNSSEC correctly is not easy. Thus, maybe 
having a DNS cache in ser can make sense, but having a full resolver IMO 
  not.

>> Can this also be used for DNS lookups and TCP/TLS connection setup?
> 
> Yes for DNS (see above) and in general for any route-level async processing
> involving tm (e.g. lookup some part of the message in a slow DB and 
> execute automatically another route when the DB responds).
> 
> It cannot be used for TCP/TLS, but it's not needed anyway. In ser TCP
> connection setup and TCP send is already asynchronous, at least if
> you have tcp_buf_write=yes in ser.cfg (I agree it's not a very well

Interesting. Is it really completely asynchronous  with any blocking, or 
is it handed over to a dedicated "TCP send" process which is then blocked?

> (BTW: most of the core new options documentation in ser can be found
>  in NEWS)

Probably this should be merged too.

thanks
klaus