Hi Jeremy,
On 09/15/2011 07:07 PM, Jeremy Childs wrote:
Thanks, for the reply, Bogdan.
I see what you're getting at, but the problem runs a little deeper
that this, though. For the reply from the NATed UA, the dialog module
needs to store the "fixed" contact, and it has no way of getting this
information, as it only looks at the incoming header, not what
fix_nated_contact has already pushed into a lump.
I agree with this limitation - but this will affect only the case when
the dialog module has to send in dialog requests (like BYE).
In your opinion, how difficult would it be to just make $ct writable?
If it was writable, then nathelper could be coerced into putting
$avp(contact) into $ct, where it could presumable be read normally by
dialog.so. This assumes that modules have access to core variables
that may have changed since the packet was received.
The problem here is more complex as with the current design, changing a
change is impossible - basically you should first undo the prev change,
before doing a new one.
I recently ran into a similar problem with codec_delete and friends
where I need to remove a codec that has no a=rtpmap entry.
codec_delete can't find the coded to remove it, as it has no rtpmap
entry, and once codec_delete was done removing the codecs it could
find, any textops I ran on the SDP after that point corrupted the packet.
I'm not really following. Could show a simple example with an SDP + ops
you are doing?
Regards,
Bogdan
Any suggestions on how we can remove this one-rewrite limitation?
On 11-09-14 11:47 AM, Bogdan-Andrei Iancu wrote:
Hi Jeremy,
Indeed, seems to be an incompatibility here...What I would suggest is
a bit of a trick, to manually handle the NATed contact in a dialog
variable...Haven;t tried it, just an idea.
On initial INVITE :
modparam("nathelper", "received_avp", "$avp(contact)")
...
topology_hiding();
if (nat_uac_test()) {
fix_nated_register(); # puts the fix contact into received avp
$dlg_val(caller_contact) = $avp(contact);
}
...
And for sequential requests:
...
loose_route();
...
if ( match_dialog() ) {
# sequential request from callee to caller?
if ($DLG_dir=="UPSTREAM") $ru = $dlg_val(caller_contact) ;
}
Again, not tested, not sure it will work, but just an idea :)
Regards,
Bogdan
On 09/13/2011 07:30 PM, Jeremy Childs wrote:
I'm having a problem with the dialog module's topology hiding when a
UA is behind a NAT.
If I call
if (nat_uac_test()) {
fix_nated_contact();
}
topology_hiding();
The Contact header is rewritten twice - once by fix_nated_contact()
and again by topology_hiding(). This results in an invalid contact
header.
Is there an obvious way I'm missing that could make these two
modules coexist, or is the best solution to add NAT knowledge to
dlg_tophiding.c? This seems like a lot of code to duplicate.
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--
Bogdan-Andrei Iancu
OpenSIPS eBootcamp - 19th of September 2011
OpenSIPS solutions and "know-how"
--
Bogdan-Andrei Iancu
OpenSIPS eBootcamp - 19th of September 2011
OpenSIPS solutions and "know-how"
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