[SR-Users] provoke delay?

[marius zbihlei]

On 10/26/2010 05:09 PM, Alex Balashov wrote:
> Pike or ratelimit modules may facilitate this; otherwise, no.
>
>    

> --
> Alex Balashov - Principal
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>
> On Oct 26, 2010, at 9:55 AM, "Nicolas Rüger"<NicolasRueger at gmx.de>
> wrote:
>
>    
>> Hello,
>>
>> is there a mechanism to provoke a DELAY for certain incoming INVITES
>> before passing them to the callee???
>>
>>
>>      
Hello, It is not a good design practice to do it synchronously, mainly 
because the worker process will remain blocked for 30s . Imagine an 
attacker sending 30 requests and DoS the whole server , because of the 
limited number of worker process (not to mention that 30s delay means 
retrasmits from the TM layer- so these need to be handled by tm before 
the "sleep").

Anyway I wouldn't recommend a design like this.  As others suggested 
pike and ratelimite (mostly ratelimit) will allow you to drop calls from 
attackers. You could add a Retry-After header so to inform a normal UA 
to retry the request after a number of seconds.

Marius
>> Just the single message needs to be delayed as the caller might be
>> suspicios. I do already have a list in database and can check the
>> caller against the list.
>>
>> I do need something in routing logic to delay the current message
>> WITHOUT slowing down kamailio and kill performance.
>>
>>
>> something like in this pseudo_code:
>>
>> route{
>>
>>   if (is_method("INVITE")&&  !has_totag() ) {
>>     if (user_delaylist == TRUE){
>>
>>          delay_message_for(30 sec.);
>>
>>     }
>>   }
>> }
>>
>>
>>
>> Any ideas and suggestions are appreciated!
>>
>>
>> Regards,
>>
>> Nicolas
>>
>> -- 
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>>
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>>      
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