[OpenSIPS-Users] Issue with rtpengine

[Sergey Pisanko]

I tried to remove crypto strings that's not needed with "replace_body()"
function before rtpengine execution.. And I got the string what I need. But
despite this, when rtpengine is applied and proxy relays message to UA2,
rtpengine adds a string what I got rid from SDP on the previous step. And I
don't have any idea, from where rtpengine get crypto string in a changed
body. Here is what the script in this part looks like:

branch_route[invite_to_pbx] {
   xlog("outgoing to pbx");
     if(has_body("application/sdp")) {
         if (replace_body_all("a=crypto:([1-9])+( AES_CM_256)+(.*)$", "")) {
            xlog("Replaced");
         }
       rtpengine_offer("RTP/SAVP ICE=remove"));
      }
 }

I also tried to execute this in a request route, but without changing.

Can you help me to understand why rtpengine ignores changed SDP? Is my
script logic correct?

Best regards,
Sergey Pysanko.
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01/18/22,
07:13:23 PM

пт, 14 янв. 2022 г. в 17:30, Sergey Pisanko <serp87 at yandex.ru>:

> Hello.
>
> I've faced an issue when using rtpengine module with tls transport. When
> UA originates a call it pointed set of crypto
> parameters in SDP, like that:
>
> a=crypto:1 AES_CM_256_HMAC_SHA1_80
> inline:PZASLY5HoxVo6Ljz2niwxqNJ+3A2mW71SgfL75cRFtShKQIvcKVF2Y39zGd1fQ==
> a=crypto:2 AES_CM_256_HMAC_SHA1_32
> inline:LRjGKIj8wvfxDP68+5XOEmlvO2ufqxDkhJ3hUQRWzjFulFr2kBztgSjrPSSACw==
> a=crypto:3 AES_CM_128_HMAC_SHA1_80
> inline:Nup7cVUaHGb+oQPf8gg1wDmjVJOZ5K+HZdhyovzz
> a=crypto:4 AES_CM_128_HMAC_SHA1_32
> inline:rjLdKaMyQ7+YQWCcIFKkVRLd+GZxkUogGK/4i1L0
>
> But when Opensips relays original message to UA2, rtpengine removes all
> the crypto suite strings except the first one.
> Unfortunately, there is no way to configure client's behaivior to send
> certain crypto suite.
> In other side, UA2, that is PBX, doesn't support all crypto suites except
> AES_CM_128_HMAC_SHA1_80
> Is there a way to configure Opensips/rtpengine to choose specific crypto
> string or to leave crypto set without changing at all?
>
> Best Regards,
> Sergey Pysanko.
>
>
>
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