[SR-Users] fix_nated_sdp function

Hello, Can someone point me to what is wrong with this SDP: ``` v=0 o=- 3826710256 3826710256 IN IP4 100.113.232.22 s=pjmedia b=AS:386 t=0 0 a=X-nat:0 m=audio 4012 RTP/SAVP 96 8 120 121 c=IN IP4 100.113.232.22 b=TIAS:96000 a=rtcp:4013 IN IP4 100.113.232.22 a=sendrecv a=rtpmap:96 opus/48000/2 a=fmtp:96 useinbandfec=1 a=rtpmap:8 PCMA/8000 a=rtpmap:120 telephone-event/48000 a=fmtp:120 0-16 a=rtpmap:121 telephone-event/8000 a=fmtp:121 0-16 a=ssrc:886437437 cname:61141a4c6ecaa55e a=crypto:1 AES_256_CM_HMAC_SHA1_80 inline:J9gds2sgq3OQccZ4fQoy3Oh9P2sWAXGHpLx+v/Ykh3gFQtAcaD8u5zpygEw2Dw== a=crypto:2 AES_256_CM_HMAC_SHA1_32 inline:yVCi20viRSxW+7hkUDjDBfXX4eAsuNrGj96ByTpDejOww8A0+BwSDjO40U1u3A== a=crypto:3 AES_CM_128_HMAC_SHA1_80 inline:9vWxWlHSBcLYv0p+qYTviva7Bc6tUb+fKblHaQ1D a=crypto:4 AES_CM_128_HMAC_SHA1_32 inline:UlLlQR2NB1owPDx7fFyGqnq09AVFVOLB50I3f/FC ``` I'm trying to apply function "fix_nated_sdp" to it, but getting back this error: <no `IP[4|6]' in `a=rtcp' field> By looking at the source code, seems that the nextissip value is 0, and that's why it fails (nextissip value:0/len:14) Any idea why?