Thanks guys, good points indeed - let me play around and see what I can come up with.
The question is: if we find a clean solution would you be ok with adding it into the repo? I suppose initially we could even implement with compile time flag like "SPIRAL_UNIQUE_DLG" for example. Although, I don't particularly like doing this sort of thing.
I think the question is: would everyone accept having to call get_dlg(callid, ftag, ttag, branch) when according to RFC3261 a dialog should be identifiable by only the 3 (cid, ftag, ttag).
IMO, this would be a good feature to add to Kamailio, so hopefully it can be approved?
Cheers Jason
On Thu, Aug 25, 2011 at 11:29 AM, Klaus Darilion < klaus.mailinglists@pernau.at> wrote:
Am 25.08.2011 11:16, schrieb Timo Reimann:
On 25.08.2011 10:31, Klaus Darilion wrote:
Am 25.08.2011 10:14, schrieb Jason Penton:
From some initial work and testing I can confirm that this works
ONLY
when using the top Via *without* branch tags. Not sure what impact
this
could have? This is because a BYE results in a different set of branch tags from
the
original set of invite branches - I am investigating why and how
this
works now.
Sure. the branch tag is a transaction identifier and must be unique in space and time. Thus, BYE must have another tag. That's why I said you have to put some data into RR cookies - this is the only data which stays the same during the dialog (except tags and call-id).
If you only want to know if an in-dialog request is from orig->term or from term->orig, then the is_direction function is already sufficient.
If you want to detect a certain spiral leg in dialog module, IMO you have to add another matching parameter (besides tags and call-id) to dialog module which will be set as RR-cookie and retrieved from Route header for in-dialog requests. Every time the initial requests spirals through the proxy, you have to add such a cookie which of course must
be
different to the previous inserted cookie (therefore ftag is not sufficient anymore) - either generate a random identifier or reuse
some
data from the message (e.g. you could copy branch-tag to RR header as
it
should be unique)
Let me emphasize that you don't need to add a new RR cookie: You can re-use the existing one that implements DID mode and simply extend the hash function to cover that extra value you choose. (Random number or branch parameter, as Klaus mentioned; see my comments below though.)
Indeed - I have not thought about this parameter. If it would be extended to be unique it should work - as long as the DID value in in-dialog requests is correct. Thus, DID_FALLBACK mode would not work anymore.
regards Klaus
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