15 Dec
2006
15 Dec
'06
7:38 a.m.
Any way I could catch the final OK message instead of the REGISTER
message? Right now, I'm using the code below. Now I see that's not good
because I get the Expires from the client which may be higher than the
real Expires.
if( method=="REGISTER" ) {
if (!www_authorize("myrealm", "sip_conf")) {
www_challenge("myrealm", "0");
exit;
};
save("location");
avp_db_query("UPDATE sipfriends SET ipaddr='$si',
port='$sp', regseconds=$Ts+$hdr(expires), useragent='$ua' WHERE
name='$au'");
exit;
};
Bogdan-Andrei Iancu escreveu:
Hi Jerome,
you are right - a server may change the expire advertised by the
client. If it is the case or not, it's a matter of configuration in
OpenSER - see the min_expires and max_expires in the registrar module.
http://www.openser.org/docs/modules/1.2.x/registrar.html
if this params are not set, there is no risk of using the value
advertised by the client.
regards,
bogdan
Jerome Martin wrote:
On Thu, 2006-12-14 at 17:32 -0200, Juan Carlos
Castro y Castro wrote:
Forget I said that! There's $Ts +
$hdr("Expires")! That'll teach me
to always RTFA before answering!
Well, you need to be carefull about $hdr("Expires"). This is NOT the
only way a UA can specify an expiration delay for a REGISTER request.
If you take a look at the relevant parts of rfc3261
( http://www.ietf.org/rfc/rfc3261.txt ), you'll see that using an
Expires header is only one way of specifying a desired expired duration
for the REGISTER. The other way is by using a Contact header parameter
(page 60 of the rfc) :
10.2.1.1 Setting the Expiration Interval of
Contact Addresses
When a client sends a REGISTER request, it MAY suggest an expiration
interval that indicates how long the client would like the
registration to be valid. (As described in Section 10.3, the
registrar selects the actual time interval based on its local
policy.)
There are two ways in which a client can suggest an expiration
interval for a binding: through an Expires header field or an
"expires" Contact header parameter. The latter allows expiration
intervals to be suggested on a per-binding basis when more than one
binding is given in a single REGISTER request, whereas the former
suggests an expiration interval for all Contact header field values
that do not contain the "expires" parameter.
Also note that the expire parameter to a Contact header is totally
case-unsensitive ( page 32 of the RFC) :
When comparing header fields, field names are
always case-
insensitive. Unless otherwise stated in the definition of a
particular header field, field values, parameter names, and parameter
values are case-insensitive. Tokens are always case-insensitive.
Unless specified otherwise, values expressed as quoted strings are
case-sensitive. For example,
Contact: <sip:alice@atlanta.com>;expires=3600
is equivalent to
CONTACT: <sip:alice@atlanta.com>;ExPiReS=3600
A good example of a very popular SIP UA always using the Contact
header parameter method is the Linksys PAP2 ATA. On the other hand,
there are also
many popular ATAs that use the Expires header method, i.e. Audiocodes
MP1XX ATAs. So unless you're in a very controlled environment and you
don't
care at all to be generic and RFC3261-compliant, you must support
both. But
be carefull, in my experience this almost always bites you back one
day or the other.
Hope this helps,
Best Regards,
Jérôme Martin