[tor-relays] possible interference between sbws and a libressl relay (was: Measuring the Accuracy of Tor Relays' Advertised Bandwidths)

[Felix]

Hi everybody

This is an early report and has to be confirmed over the next days.

Am 2019-08-26 um 11:58 PM schrieb teor:
 >> On 27 Aug 2019, at 05:19, Toralf Förster <toralf.foerster at gmx.de>
 >> wrote:
 >>
 >>> On 8/26/19 3:14 AM, teor wrote:
 >>> We expect to have funding to fix these bugs some time in the
 >>> next month or two.
 >>
 >> So I'll just wait.
 >
 > Waiting might not help, if the issue is on your relay

Trying out different settings on server side had no effect.
The relay s/w environment seems to interfere with sbws.

At first: I run serveral relays on Freebsd since longer time and always
compile libressl, libevent, zstd and tor(-devel), like:

Jul 15 20:59:17.470 [notice] Tor 0.4.1.3-alpha running on FreeBSD
with Libevent 2.1.10-stable, OpenSSL LibreSSL 2.9.2, Zlib 1.2.11,
Liblzma 5.2.3, and Libzstd 1.4.0.

This worked fine until Aug/16 when I lost nearly all the relays guard flags:

Consensus Sep/7
ACBBB426CE1D0641A590BF1FC1CF05416FC0FF6F Planetclaire62
  Fast             !Running Stable V2Dir Valid bw=8200
  Fast             !Running Stable V2Dir Valid
!Fast              Running Stable V2Dir Valid
  Fast             !Running Stable V2Dir Valid
!Fast              Running Stable V2Dir Valid
  Fast             !Running Stable V2Dir Valid
  Fast              Running Stable V2Dir Valid bw=747
  Fast Guard HSDir  Running Stable V2Dir Valid
  Fast Guard HSDir  Running Stable V2Dir Valid bw=8180
  Fast              Running Stable V2Dir Valid bw=8180
bwauth=faravahar


No clue why this happend. Since then I searched for the reason. On
Sep/14 the change to openssl brought back the guard flag today:

Sep 14 04:20:29.748 [notice] Tor 0.4.1.5 running on FreeBSD with
Libevent 2.1.10-stable, OpenSSL 1.0.2s, Zlib 1.2.11, Liblzma 5.2.3, and
Libzstd 1.4.0.

Consensus today
ACBBB426CE1D0641A590BF1FC1CF05416FC0FF6F Planetclaire62
Fast !Guard Running !Stable V2Dir Valid bw=16000
Fast !Guard Running !Stable V2Dir Valid
Fast  Guard Running  Stable V2Dir Valid bw=14000
Fast !Guard Running !Stable V2Dir Valid
Fast  Guard Running  Stable V2Dir Valid bw=22000
Fast !Guard Running !Stable V2Dir Valid
Fast  Guard Running  Stable V2Dir Valid bw=12200
Fast  Guard Running  Stable V2Dir Valid
Fast  Guard Running  Stable V2Dir Valid bw=12100
Fast  Guard Running  Stable V2Dir Valid bw=14000
bwauth=longclaw


 >>> I don't think the sbws bandwidth authorities are causing the
 >>> issue that you're seeing with your consensus weight or flags.

The sbws bandwidth authorities now can measure the bandwidth of the relay.

Can somebody confirm my observation or has prove (please no speculations).


Am 2019-08-28 um 8:09 PM schrieb Toralf Förster:
> On 8/26/19 11:58 PM, teor wrote:
>> Waiting might not help
> Indeed.
>
> The picture is:
> 	A bunch of relays, running since a longer time by different operators, are affected.
> 	Examples are [1], [2] and [3]
> 	The hoster do differ (Hetzner, i3D.net B.V, Host Europe GmbH), the OS too (Linux, Open BSD, FreeBSD), and the country (DE, NL)
>
> So the root cause might be a peer those hosters route their traffic too -or- located in the Tor software -or- ...
>
> It seems there's nothing I can do here to narrow down the issue nor to blame my hoster, or?
> I do wonder about the number of relays affected, meaning lost their Guard flags around 15th of August and didn't get it back till today?
>
> [1] me : 			https://metrics.torproject.org/rs.html#details/63BF46A63F9C21FD315CD061B3EAA3EB05283A0A
> [2] Felix:			https://metrics.torproject.org/rs.html#details/CE47F0356D86CF0A1A2008D97623216D560FB0A8
> [3] me searched this too:	https://metrics.torproject.org/rs.html#details/0CDCFB0B6E1500E57BDD7F240543EBAEF81C11CA

Toralf, may-be your s/w environment shows similar incompatibility to
sbws? But may-be it's something different. Good luck!


--
Cheers, Felix