Re: [Devel] [Users] nathelper/rtpproxy when both SIP UA are behind same NAT

I agree that the solution that was presented is BAD for the reasons stated by both of us and probably more :) Perhaps using $Ri after the successful lookup() and comparing it to the $src_ip AVP would work. The problem was trying to compare a pseudo variable with an AVP. The doc <snipped below> does not state that pseudo variables can be used by avp_write(). Pseudo-variables can be used with following modules of OpenSER: * avpops - function “avp_printf()” * xlog - functions “xlog()” and “xdbg()” I did try to use avp_write() to save a pseudo variable to an AVP but was unsuccessful. Do you have an example of writing a pseudo variable to an AVP ? Regards, Norm Tavis P wrote: > Another, more lightweight solution, is: > > After a successful lookup(location) you can compare the received IP > address ($si) with the destination domain/ip address returned from > the > "lookup" function call ($rd), i think these two pieces of information > are reliable for this purpose > > This way you don't have to make extra database calls to determine > locality > > Also if you want to compare pseudo variables you can first write > them to > an AVP using "avp_write" and then you can make use of "avp_check" > with > data sourced from a pseudo variable > > Norman Brandinger wrote: > > > > > > >> I have looked into the problem related to saving saving resources by >> not calling rtpproxy or mediaproxy when both the caller and >> callee are >> behind the same NAT. >> >> This topic has been discussed many times however, there have been no >> "working" examples, or even partial examples posted (that I'm aware >> of). >> >> Below is a solution to the problem, but is a BAD hack at best. >> >> This solution is BAD because AVP's are added to the usr_preferences >> table during the registration process, but there is no notification >> that a registration has expired and is no longer valid. A cron job >> could be run periodically to delete all received_ip AVP's with no >> matching entry in the location table, but this is another hack to >> fix >> the first hack. >> >> The solution is BAD because a database calls must be made to save >> the >> received_ip address into an AVP, then another database call must be >> made to reload the value just so that it can be tested against the >> caller's $src_ip. A pseudo variable $Ri already exists that >> contains >> the value we use in received_ip, but I have not been able to find a >> way for avp_check() to use $Ri. >> >> The solution is BAD because it will fail when the SIP device(s) are >> behind more than a single NAT router. I believe this is not an >> issue >> for 95% of the users and 99% of the small office or home users. >> >> I think that a better solution would be to enhance avp_check() to >> accept pseudo variables for the "value" parameter. This would >> remove >> the need for any database calls. >> >> I'm cross-posting this response to the developers list to bring this >> to their attention and ask for suggestions (it's possible that I've >> totally missed something). If a decision is made to open the avpops >> module to pseudo variables (other than just avp_print()), I would >> suggest the following be looked at: >> >> avp_check() the value parm should accept pseudo variables >> avp_write() the value parm should accept pseudo variables >> avp_pushto() the name parameter should accept pseudo variables >> avp_op() the value parameter should accept pseudo variables >> >> Regards, >> Norm >> >> >> 1) During REGISTER processing, place the following code. I would >> suggest that you put the code "after" all authentication checks and >> "after" the save("location") statement. >> >> # Delete any previously saved IP addressess from the user. >> avp_db_delete("$from/username","s:received_ip"); >> >> # Save the source IP address of the user into an AVP called >> received_ip. >> # The saved IP address should be the public address of the NAT >> router. >> avp_write("$src_ip", "s:received_ip"); >> >> # Save the AVP received_ip into the usr_preferences tables >> associated >> with the user that just registered >> avp_db_store("$from/username","s:received_ip"); >> >> 2) During INVITE processing (or wherever you make the decision to >> use >> or not use rtpproxy / mediaproxy) , place the following code. >> >> >> #--------------------------------------------------------------------------- >> >> >> >> # Are the caller and callee behind the same NAT ? >> >> #--------------------------------------------------------------------------- >> >> >> >> avp_db_load("$to/username", "s:received_ip"); >> if (avp_check("s:received_ip", "eq/$src_ip")) { >> setflag(CALLER_AND_CALLEE_ ARE_BEHIND_THE_SAME_NAT); >> }; >> >> >> >> _______________________________________________ >> Devel mailing list >> Devel(a)openser.org >> http://openser.org/cgi-bin/mailman/listinfo/devel >> >> >> >> > > > >