Bandwidth auths should publish average and weighted onionskin failure rates

While testing for path bias rates, I've noticed that the onionskin failure rate in the network can vary as much as +/- 30% in the matter of a few hours. This is rather insane.

We should publish statistics on this failure rate over time somehow. This might be a metrics task, but if the bandwidth auths do it, we can have them set consensus parameters for the path bias code to decide on how loudly to scream and when (see Proposal 209).

For that, I think I want network-wide averages, as well as consensus-bandwidth weighted averages. The path bias levels should be set using consensus-bandwidth weighted values.

See also legacy/trac#5457 (moved), but I don't think we should do that anymore, based on how easy it seems to be to cause onionskin overload.

moved from torflow#7281 (moved)

added component::core tor/torflow in Legacy / Trac priority::low in Legacy / Trac privcount in Legacy / Trac severity::normal in Legacy / Trac status::new in Legacy / Trac type::enhancement in Legacy / Trac labels

FYI: This requires the bw auths upgrading to a tor client that supports legacy/trac#7039 (moved) to get actual REASON=RESOURCELIMIT reason codes back as opposed to REASON=INTERNAL. However, we can just assume all first-hop circuit failures with open orconns are onionskin failures to start.

I think the way we want to do this is simple multiplication. Assuming the bw auth ambient failure really is an accurate measurement of the network-wide failure rate, then the adversary needs to fail 1.0-c/n of the remaining successful circuits in order to capture those routes.

Therefore, if the bandwidth auths publish a weighted circuit success rate as wcirc_success, the dirauths can just multiply the initial path bias numbers by this wcirc_success value to get new values for the consensus parameters pb_noticepct, pb_warnpct, and pb_extremepct.

As an alternative, see legacy/trac#7509 (moved).

FYI: The fixes for legacy/trac#7157 (moved) mean we only have to measure onionskin success rates for exit nodes, not the whole network.

Trac:
Cc: N/A to aagbsn@extc.org

We probably won't implement this in torflow, see legacy/trac#13630 (moved) for a replacement.

Trac:
Severity: N/A to Blocker
Sponsor: N/A to N/A
Reviewer: N/A to N/A

Priorities and Severities in torflow are meaningless, setting them all to Medium/Normal.

Trac:
Severity: Blocker to Normal
Priority: High to Medium

aagbsn was the default owner, unassigning

Trac:
Owner: aagbsn to N/A
Status: new to assigned

Mark all tickets that are assigned to nobody as "new".

Trac:
Status: assigned to new

Trac:
Cc: aagbsn@extc.org to aagbsn@extc.org, juga

Trac:
Parent: legacy/trac#5456 (moved) to 25925

Trac:
Parent: 25925 to legacy/trac#25925 (moved)

Replying to teor:

We probably won't implement this in torflow, see legacy/trac#13630 (moved) for a replacement.

Since currently the directory authorities do not use circuit failure information generated by Torflow, what would be the idea on how to solve this ticket?

We do not need this feature to replace torflow with sbws.

It is ok if we don't implement it. If you want to implement it, please do not spend more than half a day doing it.

Trac:
Priority: Medium to Low

This is a relay statistics task, not a bandwidth authority task

Trac:
Keywords: N/A deleted, privcount added
Parent: legacy/trac#25925 (moved) to N/A

mentioned in issue legacy/trac#7509 (moved)

mentioned in issue tpo/core/tor#7509 (closed)

moved from legacy/trac#7281 (moved)

added Feature label and removed 1 deleted label

removed 1 deleted label

added Icebox label

Hmm, I think this doesn't apply anymore, but just in case @mikeperry can have a quick look, moving this to /team.

added Bandwidth scanner operators label

removed Feature label

mentioned in issue torflow#13630 (closed)

The overload line basically does this now. I don't think we need this in sbws.

closed

removed Bandwidth scanner operators label

added Bandwidth scanner operators label