27 Feb
2004
27 Feb
'04
12:23 a.m.
In some situations ser inserts two Route header fields (for example
UDP->TCP traversal). Such route header fields have a special parameter
so that ser knows that there are two of them and it should remove both
of them when processing the message, example:
Route: <sip:12@ser.host;lr;r2>
Route: <sip:23@ser.host;lr;r2>
Unfortunately there are many broken implementations that remove unknown
parameter from Route header fields and even such that remove lr
parameter so ser can receive:
Route: <sip:12@ser.host>
Route: <sip:23@ser.host>
If a previous host was a strict router, you will receive:
METHOD sip:12@ser.host SIP/2.0
Route: <sip:23@ser.host>
loose_route will rewrite the Request-URI with the route header field and
you will have a message with the IP of your server in the Request-URI.
Now imagine what happends if uri == myself follows.
That's one case, another case is when you receive message like this:
METHOD sip:1.2.3.4@callee
Route: <sip:your_server;lr>
Route: <sip:foreing_server;lr>
Route containing your_server will be removed because it belongs to your
server and the message will be forwarded to "foreign_server". But the
Request-URI does contain a different value -- so all subsequent tests in
the config file which operate on the Request-URI will be wrong.
loose_route returns 1 in those two cases and 0 in all other. When
loose_route returns 1, you know that you should just apply all security
restrictions (like when forwarding to a PSTN gateway) and send the
message. All the tests and modification which are performed when you are
processing a request establishing a dialog should not be applied here.
Jan.
On 26-02 17:23, Klaus Darilion wrote:
Andrei Pelinescu-Onciul wrote:
On Feb 25, 2004 at 18:56, Klaus Darilion
<klaus.mailinglists(a)pernau.at>
wrote:
I'm still confused ... the BYE request from Windows Messenger with a
route-set will be handled be the if(loose_route()){...} block, but not
the BYE request from Xlite with a route-set. But shouldn't also the BYE
from Xlite be processed in the if(loose_route()){...} block? I don't
want to care about in-dialog requests in my routing logic which deals
with voicemail, hunt groups ...
An other possibility would be to remove the t_relay in the loose_route
block, so that all in-dialog requests (Messenger and xlite) are
processed by the following routing logic.
thanks,
klaus
I'm still confused. I try to write it down in
my own words as far as I
understand it and hope that somebody will confirm or correct my
statements:
So, loose_route does the rewritting of the req-URI (strict routing) and
removing of route headers if there are Route: headers in the request.
After that, the request should be routable by t_relay.
The loose_route function will rewrite the req-URI of "strict_routing"
messages. So the if(uri==myself) statement shouldn't be TRUE anymore, or
does this statement checks the original req-URI?
No, it checks the "new" uri, so in the strict router case you are right,
it won't match (of course assuming the new uri!= proxy).
In the loose router case, the message will be sent to the loose route
uri (not to the request uri) and the request uri will not be changed,
so your uri==myself could match although the message will be sent
elsewhere.