On 7/3/12 5:16 PM, Timo Teras wrote:
On Tue, 03 Jul 2012 16:23:45 +0200 Daniel-Constantin Mierla
<[email protected]> wrote:
On 7/3/12 3:49 PM, Timo Teras wrote:
On Tue, 03 Jul 2012 12:16:38 +0200 Daniel-Constantin Mierla
<[email protected]> wrote:
Hello,
On 7/3/12 8:02 AM, Timo Teras wrote:
Hi,
I fixed some uac From rewriting issues in commit e1d1c774c9ac0b4d,
however even with the latest versions I'm still seeing corruption
in From headers when they are rewritten for the whole dialogue
(from_restore_mode=auto, the default).
I spent some time analyzing the problem and the problem seems to
be connected with the fact that only the bitwise difference of the
original and modified URI are stored (XOR). The only purpose for
this appears to be the idea to save only the difference in the rr
params instead of two full URIs.
However, it appears that in many cases (especially call transfer)
the From header will be altered during dialogue. This is
explicitly allowed in RFC 3261 ยง 20.20:
The From header field indicates the initiator of the request.
This may be different from the initiator of the dialog.
I've seen this in practise with few commercial SIP stacks.
Sometimes the changes are minor, or even trivial - but with the
difference encoding having even one character changed (e.g.
case), being deleted or added will result in the whole header
being corrupted.
I'm now wondering if we should just store both URIs in the rr
params. While taking little more space, it should fix us sending
garbage to the wire (which usually results in dropped call as the
remote will reject the garbage messages).
Any better ideas?
it makes sense storing the entire value. Not sure if anyone else
will want to be made configurable via mod param, I will go for
simplest approach and have only the correct option, it will help
in code maintenance.
Sounds good. Should probably do it for the stable branches too. I
can help with some of this, if needed. You have any estimate for
the fix?
I just expressed my opinion on how to fix it, but there is no plan
for me to work on it in the near future, being caught in other tasks
and traveling. So you can go ahead and make a patch to fix it for
master, then later, based on the impact, it can be backported.
Ah. Ok. "I will go" just sounded like you'll do it. Sorry for
confusion. I'll try to take stab at it then when I get a minute for
it. :)
"I would go" would have been more appropriate, indeed. I can help
reviewing when you have it, nothing else in short term unfortunately.
Cheers,
Daniel
--
Daniel-Constantin Mierla - http://www.asipto.com
http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda
Kamailio Advanced Training, Seattle, USA, Sep 23-26, 2012 -
http://asipto.com/u/katu
Kamailio Practical Workshop, Netherlands, Sep 10-12, 2012 -
http://asipto.com/u/kpw
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