[Users] Checking Request-URI

[Klaus Darilion]

Andreas Sikkema wrote:
> Hi,
> 
> Yesterday I noticed something strange happenign one on of our 
> servers. Calls were being sent to servers within our VoIP 
> platform by OpenSER without (as far as I can see) really being 
> handled according to our OpenSER configuration.
> 
> When I looked into it, I found that the Request-URI contained 
> the IP address of the internal server, instead of the IP address 
> of our OpenSER machine or our SIP domain.

Maybe someone sent a SIP message with the local IP address in the R-URI 
to your proxy. According to your config this should not matter as you 
rewrite the domain for every incoming SIP request - except for loose-route.

For loose-route I would suggest to check for a to-tag too. Then, the 
called SIP UA should reject the call. You could also use dialog module 
to see if a dialog exists before forwarding in loose_route.

regards
klaus


> 
> How can I check that the Request-URI contains only the SIP 
> domain or the IP address of the OpenSER server? 
> 
> Might this have something to do with the loose_route() block?
> 
> Here's (heavily edited) basically our INVITE handling code from 
> openser.cfg:
> 
> if (loose_route())
> {
> 	use_media_proxy();
> 
> 	t_relay();
> 	exit;
> };
> 
> if (method=="INVITE")
> {
> 	t_on_reply("1");
> 
> 	rewritehost("SIP_DOMAIN");
> 
> 	# Check if it is international number format
> 	if (uri=~"^sip:00")
> 	{
> 		strip(2);
> 	};
> 
> 	if ( (method == "INVITE") )
> 	{
> 		if (!proxy_authorize("SIP_DOMAIN", "subscriber"))
> 		{
> 			proxy_challenge("SIP_DOMAIN", "0");
> 			exit;
> 		};
> 
> 		# let's check from=id ... avoids accounting confusion
> 		if (!check_from())
> 		{
> 			sl_send_reply("403", "That is ugly -- use
> From=id next time (gw)");
> 			exit;
> 		};
> 	};
> 
> 	if (is_uri_host_local())
> 	{
> 		log("ATS: incoming message is for a local host ($tu)");
> 
> 		route(3);
> 	};
>