[OpenSIPS-Users] Feature request - pseudo-variable for destination IP address

Vitalii Aleksandrov vitalik.voip at gmail.com
Thu Jul 18 10:53:41 EDT 2019


Hi,

Original question was about different thing but the destination IP of a 
request or reply is not hard to get. I wrote a small module which 
extracts the destination uri from ru (du) for requests and from via for 
replies, makes a dns resolve if it's a domain name and then detects the 
outgoing interface of opensips and exports it as a PV to config. The 
goal was to configure rtpengine's direction to bridge between different 
interfaces. Adding just a few more lines of code will export the 
destination IP as a PV. Since I use dns cache module resolve happens 
only once and when t_relay() (tm module) searches for a destination it 
just reuses previously resolved values from cache. I can share it if 
anybody needs it.
> As far as I know, the equivalent variable to $si on the destination side is either $dd, which may not always be set, or $rd. Those are not guaranteed to be IP addresses, however. If DNS is being used, I don't believe OpenSIPS provides the results of the DNS lookup to the script in any variable, so I don't think there is a way to find the actual IP aside from doing your own DNS lookup (or possibly using the dns_cache module and snooping the cache, but I have had issues with this module in the past.)
>
> Ben Newlin
>
> On 6/28/19, 10:16 AM, "Users on behalf of rob.dyck at telus.net" <users-bounces at lists.opensips.org on behalf of rob.dyck at telus.net> wrote:
>
>      Unfortunately the address of the interface where the request was receeived is private. I am using 1 to 1 NAT.
>      
>      ----- Original Message -----
>      From: "Ovidiu Sas" <osas at voipembedded.com>
>      To: "OpenSIPS users mailling list" <users at lists.opensips.org>
>      Sent: Thursday, June 27, 2019 3:31:34 PM
>      Subject: Re: [OpenSIPS-Users] Feature request - pseudo-variable for destination IP address
>      
>      Check out the $Ri pvar:
>      https://www.opensips.org/Documentation/Script-CoreVar-3-0#toc78
>      
>      -ovidiu
>      
>      On Thu, Jun 27, 2019 at 6:23 PM rob.dyck at telus.net <rob.dyck at telus.net> wrote:
>      >
>      > I was looking for something similar to the $si PV but for the destination IP address. Either it doesn't exist or I am blind. I can't find things in the refrigerator either.
>      >
>      > The motivation.
>      >
>      > I have a working instance of Opensips with a basic residential configuration. I extended it to allow calling UAs on the LAN from the outside. It is a typical residential LAN without a fixed IP address. Dynamic DNS is working for me. I read the tutorial about Opensips behind NAT. Following the recommendations there I was able to setup rtpproxy, the advertised address and an alias for my Opensips. Initial testing using a softphone on a laptop using either WiFi or a mobile phone tethered to the laptop worked well. However it seems that some UAs will not accept a domain name in the SDP connection. The UAs that failed could be made to work by coding in an IP address. This is not a satisfactory solution because the router's address may chaange. There is probably some convoluted way to import the needed address into the script.  A pseudo-variable representing the destination IP address of the received INVITE or 200 OK could then be passed as the advertised address to the rtpproxy module.
>      >
>      > Thank you for having a look.
>      > Rob
>      >
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>      --
>      VoIP Embedded, Inc.
>      http://www.voipembedded.com
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