rtpengine - media processing for fun and profit Learn how to relay, encrypt, capture, record and monitor RTP streams flowing through your network.

1. rtpengine
media processing for fun and profit
Andreas Granig • 09.05.2017
<agranig@sipwise.com>

2. Media Processing?
TranscodingRelaying
Recording
Transscribing
Encrypting
Injecting
Monitoring
Capturing

3. Agenda
Introduction
Relaying
Capturing
Encrypting
Recording
Monitoring

4. Introduction
rtpengine is…
○ a media relay
○ used by (but not limited to) Kamailio
○ kernel based
○ highly available
○ doing crypto stuff for WebRTC
○ hosted at github.com/sipwise/rtpengine
○ much more!

5. Relaying
rtpengine Kamailio Module
controlling
rtpengine Daemon
driving
rtpengine Kernel Module

6. Relaying
rtpengine
Kamailio
SIP
RTP
original SDP +
meta info
modified SDP +
meta info

7. Relaying
Kamailio
loadmodule “rtpengine.so”
modparam(“rtpengine”, “rtpengine_sock”,
“udp:127.0.0.1:12221”)
route {
...
rtpengine_manage();
...
}
Daemon
# rtpengine
--interface=ext/1.2.3.4
--listen-ng=127.0.0.1:12221

8. Encrypting
Transform SDP Profiles
for bridging SIP and WebRTC,
Encrypt/Decrypt DTLS-SRTP
in Kernel

9. Encrypting (eg. WebRTC Bridging)
rtpengine
Kamailio
SIP
RTP
original SDP +
meta info
modified SDP:
● changed profile
● added ICE candidates
● RTCP mux
DTLS-SRTP

10. Encrypting
Kamailio
loadmodule “rtpengine.so”
modparam(“rtpengine”, “rtpengine_sock”,
“udp:127.0.0.1:12221”)
route {
rtpengine_offer(“RTP/SAVPF ICE=force ”);
}
reply_route {
rtpengine_answer(“RTP/AVP ICE=remove
rtcp-mux-demux”);
}
Daemon
# rtpengine
--interface=ext/1.2.3.4
--listen-ng=127.0.0.1:12221

11. Capturing
Write Streams as PCAP
into spool directory,
Inspect with Wireshark
for further analysis.

12. Capturing
metainfo
/var/spool/recordings/meta//var/spool/recordings/pcap/
rtpengine
Kamailio
out.pcap
SIP
RTP

13. Capturing
Kamailio
loadmodule “rtpengine.so”
modparam(“rtpengine”, “rtpengine_sock”,
“udp:127.0.0.1:12221”)
route {
...
rtpengine_manage(“record-call”);
...
}
Daemon
# rtpengine
--interface=ext/1.2.3.4
--listen-ng=127.0.0.1:12221
--recording-method=pcap
--recording-dir=/tmp/rtp
--recording-format=eth

14. Recording
Expose call data in meta files
to pick up new calls,
Emit RTP via /proc
for further processing,
Read, transcode & store Data
as WAV or MP3

15. Recording
recorder
metainfo /var/spool/recordings/
/proc/rtpengine/0/calls/
rtpengine
Kamailio
out.wav
/nfs/recordings/Packet
Queue
SIP
RTP

16. Recording
Kamailio
loadmodule “rtpengine.so”
modparam(“rtpengine”, “rtpengine_sock”,
“udp:127.0.0.1:12221”)
route {
...
rtpengine_manage(“record-call
metadata=uuid:$var(aid)|uuid:$var(bid)”);
...
}
Daemon
# rtpengine
--interface=ext/1.2.3.4
--listen-ng=127.0.0.1:12221
--recording-method=proc
--recording-dir=/var/spool/rtpengine

17. Monitoring
Collect and Analyze RTP & RTCP
to calculate MOS
or duplicate to Homer,
Expose to Kamailio on delete
for storing and reporting

18. Monitoring

19. Monitoring (Homer)
Kamailio
loadmodule “rtpengine.so”
modparam(“rtpengine”, “rtpengine_sock”,
“udp:127.0.0.1:12221”)
route {
...
rtpengine_manage();
...
}
Daemon
# rtpengine
--interface=ext/1.2.3.4
--listen-ng=127.0.0.1:12221
--homer=10.10.10.5:9060
--homer-protocol=udp
--homer-id=99

20. Monitoring (native)
Kamailio
loadmodule “rtpengine.so”
modparam(“rtpengine”, “rtpengine_sock”,
“udp:127.0.0.1:12221”)
modparam(“rtpengine”, “mos_min_pv”,
“$avp(mos_min)“)
modparam(“rtpengine”, “mos_max_pv”,
“$avp(mos_max)“)
modparam(“rtpengine”, “mos_average_pv”,
“$avp(mos_avg)“)
route {
# invite:
rtpengine_offer();
# session-timer:
rtpengine_query();
# bye:
rtpengine_delete(“to-tag”);
xlog(“L_INFO”, “Call-ID $ci MOS
$avp(mos_min)/$avp(mos_max)/$avp(mos_avg)”);
# curl, acc, db/ndb for further exposure
}

21. Questions?
<agranig@sipwise.com>