11 Jul
2006
11 Jul
'06
10:18 p.m.
I repost Jan's original description of the "select identifier"
functionality. Since then, more select identifiers have been added, both from core and
modules.
g-)
SER core can parse select identifiers using the configuration parser.
A select identifiers begins with @ characters and contains several
components/tokens delimited by . (unless it is integer component).
Integer components are enclosed in [], for example:
@contact[1].uri
This identifier is converted into binary structure which contains the
array of components. After that the parser tries to lookup function
that matches the identifier.
Available functions are arranged in a tree-like structure. When
looking up a function the tree is traversed (starting at the root)
until the parser finds corresponding function. The part of the tree
containing TLS functions looks like:
"tls"-+-"peer"-+-"subj"-+-"name"
(select_peer_name())
| \
| "state" (select_peer_state())
|
+-"issuer"-+-"name" (select_peer_issuer_name())
\
"state" (select_peer_issuer_state())
Thus when you write @tls.peer.subj.state in the configuration file
then the parser will traverse the tree until it reaches
select_peer_state() function and then it would remember that this
function should be called.
The tree of identifiers and functions is built dynamically at runtime.
This is a nice feature becase this way modules can register their own
functions or whole subtrees and make their functions available in the
configuration file.
Thus if you load TLS module then all @tls.* selects become avaiable,
if you do not load the module they are not available. Only a couple of
core functions and the framework is built in the core, the rest can be
in modules.
This framework is currently used in tls and xmlrpc modules. XMLRPC
module exports the name of the XML-RPC method to the script. TLS
module exports information from TLS layer.
The SER core itself contains a couple of functions that can retrieve
various parts of a SIP message:
@from, @from.uri, @to, @to.uri, @from.tag, @from.name, @to.tag.
@to.name, @from.params, @to.params, @contact, @contact.uri,
@contact.params, @contact.expires, @contact.q, @via, and so on.
TLS related functions are described in a separate email.
sip wrote:
Sounds like something I might look more into. Thanks,
Greger. Is there
anything written more about @var constructs? I checked the admin guide (I
know... that was kind of silly considering how out of date it is ;) ), and
tried to do a search in Google (it seems to ignore the @, so @var just gives
me every message with the word 'var' in it) and didn't see anything. Is
there
anything over at OnSIP discussing it?
N.
On Tue, 11 Jul 2006 08:35:11 +0200, Greger V. Teigre wrote
If this functionality was added in later openser
versions than 0.9,
it will most likely not be in SER. What you are describing is hard
to do with the avpops version in 0.9. The avpops module was generic
enough to do more than it was designed for; making some code
operations quite dirty in 0.9 (using the ruri as a temporary storage
while manipulating a variable). SER head uses @var to more directly
access data instead of going through a module. You may want to have
a look at it! g-)
sip wrote:
> Is there a version of textops that can do substs with AVPs that will work on
> SER 0.9.6 or is that an openSER-only modification of the code?
>
> I'm curious because we're ALSO running into the issues of charging the
> call-forwarding user for forwarding a call to the PSTN instead of charging the
> calling party. Ideally, I'd like to rewrite the from address solely for the
> purpose of authenticating the user who's doing the forwarding and charging him
> for the call, but that would likely break things as there'd be no way to get
> back to the original user if I just rewrote the from username.
>
> SO, I thought, why not let the b2bua handle the details and just forward a uri
> with a prefix string that includes the user who's forwarding the call (the
> original RURI instead of just the rewritten one).
>
> And there's the trick. How do I craft a RURI out of bits and pieces of things
> into one long RURI?
>
> If it were all the same number, I could use prefix, but it's dynamic (as is
> the nature of most things), so prefix won't work.
>
>
> How do I take
>
> RURI=1105
>
> And add to it:
>
> The rewritten RURI from the call forwarding info: 18005551212
>
> AND the prefix for the b2bua auth: 9999
>
> To make:
>
>
> new ruri: 9999110518005551212
>
>
> N.
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