[Freeswitch-users] ZRTP negotiation taking almost 10 seconds every time

[Peter Villeneuve]

Answering myself since I seem to have finally figured it out. Hopefully
this will save others the time I've spent debugging this.

The delay happens because ICE in FS is not responding correctly to
CSipSimple's stun binding requests, which eventually timeout.
If I turn off ICE in CSipSimple, then ZRTP negotiation happens almost
instantly as it should.

I believe there's an issue with FS's ICE implementation. Others seem to
have noticed the same problem (see
http://lists.freeswitch.org/pipermail/freeswitch-users/2014-June/105877.html
)

Is it possible to tweak and/or turn off ICE in FS?

Thanks


On Tue, Jun 10, 2014 at 6:23 PM, Peter Villeneuve <petervnv1 at gmail.com>
wrote:

> Hi,
>
> I've been trying to debug why ZRTP negotiation with FS as endpoint takes
> almost 10 seconds every single time. I remember in the past ZRTP
> negotiation used to take 2 to 3 seconds at most.
>
> I'm calling MoH extension from CSipSimple with ZRTP enabled to test it out
> and indeed it always takes 9 seconds to negotiate the ZRTP exchange. And
> even after it does it successfully and enteres secured state, I still see a
> lot of errors related to failed decryption.
>
> I have posted the FS and CSipSimple logs on pastebin. FS log here
> http://pastebin.com/WNGcpTqB  and CSipSimple log here
> http://pastebin.com/DfW5gqSW
>
>
> These are the relevant excerpts from FS which may help to shed light as to
> what's going on. You can see that the zrtp hellos from FS apparently never
> reach the CSipSimple client:
>
> *2014-06-10 16:17:55.949864 [DEBUG] switch_rtp.c:1352  [ zrtp engine]:
> WARNING! HELLO Max retransmissions count reached (20 retries). ID=9*
>
> But then you see a five second interval of nothing until CSipSimple's ZRTP
> hello reaches FS and the negotiation starts:
>
> *2014-06-10 16:17:55.949864 [DEBUG] switch_rtp.c:1352  [        zrtp]:
> Stream ID=9 CLEAR switching <START> ---> <NOZRTP>.*
> *2014-06-10 16:18:00.789889 [DEBUG] switch_rtp.c:1352  [  zrtp utils]:
> Received <Hello   > packet with ssrc=0 seq=1/1 size=168.
> Stream9:CLEAR:NOZRTP.*
>
> Once that's successfull indeed ZRTP appears to work properly, although I
> still see a lot of errors like this:
>
> 2*014-06-10 16:18:01.509898 [DEBUG] switch_rtp.c:1352  [zrtp protoco]:
> ERROR! Decrypt failed. ID=9:DH s=SRTP authentication failure (RTP size=51
> ssrc=690666908 seq=20192/20192 pt=111)*
> *2014-06-10 16:18:01.509898 [DEBUG] switch_rtp.c:1352  [ zrtp engine]: Add
> 140 bytes of entropy to the RNG pool.*
>
> Now I guess this could be due to dropped packets, but I'm curious if
> others have seen the same thing in their setups.
> Also, I see this message in the FS logs. On the CS logs everything seems
> to be fine. Why does FS think that CS needs new un-enrolment? I presume
> that nedpint is actually a typo for endpoint, but this just made me more
> confused.
>
> *2014-06-10 16:18:01.769867 [DEBUG] switch_rtp.c:1352  [zrtp protoco]:
> INFO! The user requires new un-enrolment - the nedpint may clear the cache
> or perform other action. ID=9*
> *c60c4480-f0ba-11e3-aa6e-ddba267b1226 2014-06-10 16:18:01.769867 [DEBUG]
> switch_rtp.c:1323 User unenrolled!*
> *2014-06-10 16:18:01.769867 [DEBUG] switch_rtp.c:1352  [  zrtp cache]:
> cache_put() zid1=346638366666393864366363, zis2=3888449c219de624b44b3ece
> MiTM=NO*
> *2014-06-10 16:18:01.769867 [DEBUG] switch_rtp.c:1352  [  zrtp cache]:
> cache_put() Just update existing value.*
>
>
> Any ideas as to what's happening?
>
> Thanks
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.freeswitch.org/pipermail/freeswitch-users/attachments/20140610/5829a636/attachment.html