[Kamailio-Devel] Flags are not visible when processing CANCEL

[Alex Balashov]

Iñaki Baz Castillo wrote:

> This is, even if ACK (end-to-end for a 200 OK) and CANCEL are an
> "indepent" transaction, Kamailio knows that them belongs to an INVITE
> transaction.
> 
> Based on it, I think that Kamailio could retrieve INVITE transaction
> flags when CANCEL or ACK (end-to-end) arrives.

True.

Ultimately, I think this comes down to a philosophical question and a 
matter of taste.  It is not necessarily meaningful or desirable to say 
that Kamailio has visibility into the full context and state of the 
INVITE transaction when processing a CANCEL or end-to-end ACK.

Simply looking up in a table whether a transaction with that GUID and 
tags is currently being tracked is not logically equivalent to fully 
importing/superimposing all INVITE transaction state into the processing 
context for CANCEL and end-to-end ACK, in much the same way that the 
dialog module can be used to check for the existence of a 'known' dialog 
without otherwise relying on information from the dialog layer for any 
routing decisions, etc. (which is appropriate since proxies are not 
dialog-stateful).

-- 
Alex Balashov
Evariste Systems
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