[asterisk-bugs] [JIRA] (ASTERISK-26544) res_rtp_asterisk: Delay in DTLS handshake causes audio setup delay

[Marcelo Gornstein (JIRA)]

    [ https://issues.asterisk.org/jira/browse/ASTERISK-26544?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=234289#comment-234289 ] 

Marcelo Gornstein commented on ASTERISK-26544:
----------------------------------------------

Hello Richard,

That's odd. Here's the config file for Asterisk:
{code}
dtlscertfile=/webrtc/certs/STAR_vip2phone_net.crt
dtlsprivatekey=/webrtc/certs/vip2phone.net.key
{code}

And this is the one for FreeSWITCH:
{code}
      <param name="tls-cert-dir" value="/webrtc/certs"/>
{code}

In the directory /webrtc/certs I have wss.pem, which is formed by

{code}
cat STAR_vip2phone_net.crt vip2phone.net.key > wss.pem
{code}

And that's the file being used by FreeSWITCH. I don't have a certificate generated specifically for this, and I haven't included the string FreeSWITCH on it either.

Any other thoughts to track this down?

Thanks!

> res_rtp_asterisk: Delay in DTLS handshake causes audio setup delay
> ------------------------------------------------------------------
>
>                 Key: ASTERISK-26544
>                 URL: https://issues.asterisk.org/jira/browse/ASTERISK-26544
>             Project: Asterisk
>          Issue Type: Bug
>      Security Level: None
>          Components: Resources/res_rtp_asterisk
>    Affects Versions: 13.6.0, 13.9.0, 13.12.0, 13.11.2, 13.12.1, 14.0.0, 14.1.1
>         Environment: Amazon Linux: 4.4.23-31.54.amzn1.x86_64 #1 SMP x86_64 GNU/Linux
> OpenSSL: 1.0.2j
> LibSRTP: 1.5.4
> SIPml5: e3152e1edf116b651de379b3cc971bf699787c26 (Fri Mar 4 09:47:48 2016 +0100)
> Chrome: 54.0.2840.71 (64-bit)
> FireFox: 49.0.2
> Opera: 41.0
> Online JSSip Demo at: https://tryit.jssip.net/
> Amazon EC2 instance
>            Reporter: Marcelo Gornstein
>            Assignee: Unassigned
>         Attachments: 54752_jira_asterisk_26544_v13_test.pcap, 54755_jira_asterisk_26544_v13_test_force_dtlsv1.pcap, cert.txt, dtls-handshake-audio-delay-asterisk-14.1.1-2.zip, dtls-handshake-audio-delay-asterisk-14.1.1-3.zip, dtls-handshake-audio-delay-asterisk-14.1.1.zip, freeswitch-capture-call-without-delay.zip, jira_asterisk_26544_v14_force_dtlsv1.patch, jira_asterisk_26544_v14_test.patch, res_rtp_asterisk.c.rej, screencapture-ssllabs-ssltest-analyze-html-1480426789448.png, sip_trace.txt
>
>
> Hello,
> It seems that there is a delay in the audio setup when using WebRTC with latest Asterisk versions and latest browser versions (described in the Environment section).
> Sometimes there is no delay, but most of the time the delay goes between 1 second to a couple of minutes. 
> This seems to be related to a delay in the DTLS connection handshake between Asterisk and the browser (although this is just a guess after trying to isolate the issue).
> sip.conf
> {code}
> [100]
> nat=force_rport,comedia
> host=dynamic
> type=friend
> secret=secret
> disallow=all
> allow=g722
> icesupport=yes
> transport=wss
> dtlsenable=yes
> dtlsverify=no
> dtlscertfile=/cert.crt
> dtlsprivatekey=/cert.key
> dtlssetup=actpass
> videosupport=no
> encryption=yes
> avpf=yes
> force_avp=yes
> directmedia=no
> canreinvite=no
> context=wrtc
> {code}
> extensions.conf
> {code}
> [wrtc]
> exten => _X.,1,Answer
> same => n,Playback(tt-monkeys&tt-monkeys&tt-monkeys&tt-monkeys&tt-monkeys&tt-monkeys&tt-monkeys&tt-monkeys&tt-monkeys&tt-monkeys&tt-monkeys&tt-monkeys&tt-monkeys&tt-monkeys&tt-monkeys&tt-monkeys&tt-monkeys)
> same => n,Hangup
> {code}
> rtp.conf
> {code}
> [general]
> rtpstart=6000
> rtpend=65535
> icesupport=true
> [ice_host_candidates]
> x.x.x.x => y.y.y.y ; x.x.x.x is the internal IP, y.y.y.y is the external IP
> {code}
> [Edit by Rusty - removed excessive debug in description field as per issue tracker guidelines. Moving to attachment.]
> FireFox shows this in its logs:
> {code}
> 276467712[7f8929a4aec0]: [|WebrtcAudioSessionConduit] AudioConduit.cpp:612: GetAudioFrame 
> 276467712[7f8929a4aec0]: [|WebrtcAudioSessionConduit] AudioConduit.cpp:716: GetAudioFrame GetAudioFrame:Got samples: length 320 
> {code}
> But no audio is played until some (random) number of seconds pass, and this logs shows up:
> {code}
> 261443584[7f89265334a0]: Flow[568ce410feebc53d:0,rtp(none)]; Layer[dtls]: PacketReceived(2001)
> 261443584[7f89265334a0]: Flow[568ce410feebc53d:0,rtp(none)]; Layer[dtls]: Checking digest, algorithm=sha-256
> 261443584[7f89265334a0]: Flow[568ce410feebc53d:0,rtp(none)]; Layer[ice]:  SendPacket(75) succeeded
> 261443584[7f89265334a0]: Flow[568ce410feebc53d:0,rtp(none)]; Layer[dtls]: ****** SSL handshake completed ******
> 261443584[7f89265334a0]: Flow[568ce410feebc53d:0,rtp(none)]; Layer[dtls]: ALPN not negotiated, selecting default
> 261443584[7f89265334a0]: /builds/slave/m-rel-m64-00000000000000000000/build/src/media/mtransport/transportlayerdtls.cpp:865: Flow[568ce410feebc53d:0,rtp(none)]; 
> {code}
> EDIT: I forgot to mention that looking at the output from chrome://webrtc-internals, I noticed that during the delay the browser is stalled at ICEConnectionStateChecking. As soon as the audio is connected, it goes to ICEConnectionStateConnected.
>  
> Without changing any browser or network settings whatsoever either in the Asterisk Box or the browser's box, sometimes it just works. But most of the time the delay is present.
> With FreeSWITCH (cec0cb39830546a3a1c1df7ad7a05b05f14b8975 - Fri Oct 28 15:38:25 2016 -0500) works perfectly, every single time.
> Any help is greatly appreciated!
> Thank you.
> Best regards,



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