[SR-Users] fix_nated_contact() on REGISTER

[Andrei Pelinescu-Onciul]

On Jun 02, 2010 at 15:35, Daniel-Constantin Mierla <miconda at gmail.com> wrote:
> 
> 
> 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.

It does  c->uri.s = buf, where buf is pkg_malloc'ed and contains the
 "fixed" uri (and it's used also in insert_new_lump_after()).

I wouldn't use fix_nated_contact() for REGISTERs, but sometimes it's
 useful to fix contacts in dialogs.


Andrei