[Serusers] [Serdev] loose_route behaviour, detecting single Route with myself

[Greger V. Teigre]

I vote for a new preloaded_route() in trunk. I also suggest a new alias 
for loose_route (or rename and create loose_route as backwards 
compatible name): in_dialog() returning true if and only if the message 
being processed is and in-dialog message.
g-)

Nils Ohlmeier wrote:
> On Wednesday 11 July 2007 21:57:15 Martin Hoffmann wrote:
>   
>> Indeed. The only way loose_route() can end up using tel URIs is when
>> someone preloaded a message with a Route header and used a tel URI as
>> Request-URI, which is perfectly legal.
>>     
>
> Exactly.
>
>   
>> As for the return value of loose_route(), behaviour has changed over
>> time a bit. In 0.8 it used to return true only if there was yet another
>> Route header, ie., it returned false if this proxy was the last one in
>> the chain of record routing. This changed sometime in 0.9 to the current
>> behaviour to return true whenever there the topmost Route is this proxy.
>>     
>
> Yes. My assumption was that loose_route() returns true if the message came to 
> the proxy by the usage of Route headers. Or in other words: the routing of 
> this message was completely handle by the loose_route function because of the 
> presence of correct Route headers.
>
>   
>> In most cases this is what you want, because the presence of Routes
>> indicates an in-dialog message which you want to treat differently (In
>> practice, most UAs just forward the message to the outgoing proxy
>> without adding a Route header, which is perfectly legal as well). The
>> proper test for this, of course, is to check for the presence of a To
>> tag. But it seems to be common to all SER configs I have seen to misuse
>> loose_route() in this way.
>>     
>
> The realization of the fact that the presence or absence of To-tag is not 
> enough to decide if a request belongs to a dialog or not. The big exception 
> here is the ACK for negative replies. It has a To-tag but a dialog was not 
> established.
>
>   
>> Changing the behaviour of loose_route() yet again would mess up a lot of
>> configs as the earlier change messed up a lot of configs (it certainly
>> cost me a couple of hours debugging). Having another function would
>> probably be a better approach. Especially, since loose_route() is
>> actually the wrong name. The function does both loose and static record
>> routing.
>>     
>
> I agree, changing the return value again would not help. The big question is 
> if a preloaded request should be "handled" by the loose_route function?
>
> I guess the best solution would be to have one function preloaded() which 
> returns true on preloaded requests and just consumes the Route header. And if 
> this function returned true you could treat the request like any other 
> incoming request from one of your UAs without a Route header.
> Then you would call loose_route() only to take care of the remaining in-dialog 
> request (no matter if it is loose or strict routing).
>
> But such a seperation would mean a change in the behavior again, because 
> currently preloaded requests are also handled by loose_route() (it returns 
> true for these requests). So it would be only an option to change this in 
> head.
>
> Cheers
>   Nils
>
>
>   
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