[SR-Users] fix_nated_contact() on REGISTER

[Daniel-Constantin Mierla]

On 6/2/10 3:00 PM, Andrei Pelinescu-Onciul wrote:
> [...]
>>>>>>
>>>>>> On 6/1/10 9:07 PM, Alex Balashov wrote:
>>>>>>              
>>>>>>> No, it'll store the fixed one, in the proper contact column, not the
>>>>>>> received column. I do this all the time, even though it's not the
>>>>>>> "proper" way.
>>>>>>>                
>>>>>> should be the original one with the last version, afaik. There were
>>>>>> issues with phones accepting calls which had a different uri than the
>>>>>> address they set in contact of register.
>>>>>>
>>>>>> So, the contact details were brocken in:
>>>>>> - contact - the address from header
>>>>>> - received - built from source ip and port
>>>>>> - socket - local socket where the register was received
>>>>>>
>>>>>> Note that there are two functions, fix_nated_contact() and
>>>>>> fix_nated_registrar().
>>>>>>              
>>>>> I know. I always use fix_nated_register. I just wonder why save()
>>>>> saves the fixed contact in case of fix_nated_contact(), because
>>>>> usually we have the problem that changes to the message are only
>>>>> visible when the message is forwarded (lumps are applied)
>>>>>
>>>>>            
>>>> but are you sure the fixed contact is saved? I quick look in the
>>>> registrar code seems to take the contact from headers, which are
>>>> pointing inside original message.
>>>>          
>>> I just tested with kamailio 3.0 and you are right. Yesterday I tested
>>> with ser 0.9.? and fix_nated_contact() seemed to save the rewritten
>>> contact header - strange.
>>>        
>> I have to correct myself - I made an error during the test. Kamailio
>> 3.0 with fix_nated_contact() saves the fixed contact URI (see
>> below).
>>      
> In all versions (older ser, ser, sip-router, kamailio), the changes done
> by fix_nated_contact() will be visible when the contact is save()'d.
> fix_nated_contact() directly modifies the parsed contact, which is then
> used by save().
>
> fix_nated_register() behaves differently. In older ser version and in
> kamailio it sets and avp with the received information. This avp is then
> checked by save() and used as received info.
> In newer ser versions and sip-router modules_s/nathelper  it adds
> a received=... parameter to each contact (it doesn't set any avp).
> In this case save() will generate itself the received uri if the message
> is flagged as coming from before a NAT. save() from modules_s/registrar
> and newer sers, doesn't need fix_nated_register(), it only needs that the
> message was properly flagged in the script. It will also not look at any
> avp.
> ser's fix_nated_register() is used for replicated REGISTERs or when the
> outbound proxy is not also the registrar. It will add a "received="
> parameter to each contact and the non-local registrar
> (or the replication peer) can use it to recover the original ip:port.
>    
Interesting, thanks for these details. I never used fix_nated_contact() 
for REGISTER as fix_nated_registrar() is the natural way for me. You 
saved me some time to dig in the sources.

To understand that fix_nated_contact() translates the pointers to the 
new lump? If yes, that means the PVs for contact go there as well.

Cheers,
Daniel

-- 
Daniel-Constantin Mierla
Kamailio (OpenSER) Advanced Training
Miami, Fl, USA - June 21-23, 2010
http://www.asipto.com/index.php/kamailio-advanced-training/