rtpengine_manage: send SDP two times

[sergey-safarov]

Description

When used rtpengine_manage function then RTPengine node returns the correct response but in the outbound SIP message, SDP is duplicated.

Troubleshooting

Reproduction

Updated /etc/kamailio/kamailio.cfg like in this patch.

diff --git a/etc/kamailio.cfg b/etc/kamailio.cfg
index be71dbb54a..89960b38d8 100644
--- a/etc/kamailio.cfg
+++ b/etc/kamailio.cfg
@@ -1,4 +1,7 @@
 #!KAMAILIO
+#!define WITH_DEBUG
+#!define WITH_NAT
+#!define WITH_RTPENGINE
 #
 # Kamailio SIP Server v5.5 - default configuration script
 #     - web: https://www.kamailio.org
@@ -195,6 +198,8 @@ children=8
  *      listen=[proto]:[localip]:[lport] advertise [publicip]:[pport]
  * - it can be set many times to add more sockets to listen to */
 # listen=udp:10.0.0.10:5060
+listen=tcp:3.236.25.6:5060
+listen=tcp:[2600:1f18:578:5700::6]:5060
 
 /* life time of TCP connection when there is no traffic
  * - a bit higher than registration expires to cope with UA behind NAT */
@@ -456,7 +461,7 @@ modparam("presence_xml", "force_active", 1)
 #!ifdef WITH_NAT
 #!ifdef WITH_RTPENGINE
 # ----- rtpengine params -----
-modparam("rtpengine", "rtpengine_sock", "udp:127.0.0.1:2223")
+modparam("rtpengine", "rtpengine_sock", "udp6:rtp-us-east-1a-6.nga911.com:2223 udp6:rtp-us-east-1a-7.nga911.com:2223")
 #!else
 # ----- rtpproxy params -----
 modparam("rtpproxy", "rtpproxy_sock", "udp:127.0.0.1:7722")
@@ -528,6 +533,11 @@ request_route {
        # handle requests within SIP dialogs
        route(WITHINDLG);
 
+       if (loose_route()) {
+               route(NATMANAGE);
+               record_route();
+               route(RELAY);
+       }
        ### only initial requests (no To tag)
 
        # authentication
@@ -850,10 +860,11 @@ route[NATMANAGE] {
        if (!(isflagset(FLT_NATS) || isbflagset(FLB_NATB))) return;
 
 #!ifdef WITH_RTPENGINE
-       if(nat_uac_test("8")) {
-               rtpengine_manage("SIP-source-address replace-origin replace-session-connection");
+       if($avp(rtpengine_offer) == "done") {
+               rtpengine_manage("ICE=remove address-family=IP4 SDES=off");
        } else {
-               rtpengine_manage("replace-origin replace-session-connection");
+               rtpengine_manage("ICE=remove address-family=IP6 SDES=off");
+               $avp(rtpengine_offer) = "done";
        }
 #!else
        if(nat_uac_test("8")) {

Make a call via Kamailio node. In my case used a call with "Route" headers.

Log Messages

In Kamailio rtpengine_manage.log, you will find the correct RTPengine response, like:

9(32302) DEBUG: {1 34817407 INVITE 6b2a7c4c-a032-11eb-8c29-870daa274dfe} rtpengine [rtpengine.c:2677]: rtpp_function_call(): proxy reply: d3:sdp599:v=0^M
o=2600hz 1618708279 1618708280 IN IP4 192.168.2.10^M
s=2600hz^M
c=IN IP6 2600:1f18:578:5700::1:e^M
t=0 0^M
m=audio 16476 RTP/AVP 0 8 102 9 3 103 101 13 104 105^M
a=rtpmap:0 PCMU/8000^M
a=rtpmap:8 PCMA/8000^M
a=rtpmap:102 opus/48000/2^M
a=fmtp:102 useinbandfec=1; maxaveragebitrate=30000; maxplaybackrate=48000; ptime=20; minptime=10; maxptime=40^M
a=rtpmap:9 G722/8000^M
a=rtpmap:3 GSM/8000^M
a=rtpmap:103 SPEEX/8000^M
a=rtpmap:101 telephone-event/8000^M
a=fmtp:101 0-16^M
a=rtpmap:13 CN/8000^M
a=rtpmap:104 telephone-event/48000^M
a=fmtp:104 0-16^M
a=rtpmap:105 CN/48000^M
a=sendrecv^M
a=rtcp:16477^M
a=ptime:20^M

But SIP message will have duplicated SDP.

SIP Traffic

rtpengine_manage.pcap.gz

Additional Information

• Kamailio Version - output of kamailio -v

[centos@sbc-a2 ~]$ kamailio -v
version: kamailio 5.5.0-pre0 (x86_64/linux) 9413fc
flags: USE_TCP, USE_TLS, USE_SCTP, TLS_HOOKS, USE_RAW_SOCKS, DISABLE_NAGLE, USE_MCAST, DNS_IP_HACK, SHM_MMAP, PKG_MALLOC, Q_MALLOC, F_MALLOC, TLSF_MALLOC, DBG_SR_MEMORY, USE_FUTEX, FAST_LOCK-ADAPTIVE_WAIT, USE_DNS_CACHE, USE_DNS_FAILOVER, USE_NAPTR, USE_DST_BLOCKLIST, HAVE_RESOLV_RES, TLS_PTHREAD_MUTEX_SHARED
ADAPTIVE_WAIT_LOOPS 1024, MAX_RECV_BUFFER_SIZE 262144, MAX_URI_SIZE 1024, BUF_SIZE 65535, DEFAULT PKG_SIZE 8MB
poll method support: poll, epoll_lt, epoll_et, sigio_rt, select.
id: 9413fc 
compiled on 04:03:33 Apr  3 2021 with gcc 8.3.1

• Operating System:

[centos@sbc-a2 ~]$ cat /etc/os-release 
NAME="CentOS Linux"
VERSION="8"
ID="centos"
ID_LIKE="rhel fedora"
VERSION_ID="8"
PLATFORM_ID="platform:el8"
PRETTY_NAME="CentOS Linux 8"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:centos:centos:8"
HOME_URL="https://centos.org/"
BUG_REPORT_URL="https://bugs.centos.org/"
CENTOS_MANTISBT_PROJECT="CentOS-8"
CENTOS_MANTISBT_PROJECT_VERSION="8"

[miconda]

This is a mistake in configuration file, a value is appended twice if the function is used twice. See FAQ in wiki for details of similar cases. Use sr-users mailing list to discuss the changes you did in kamailio.cfg and figure out where is the error.