release: ChangeLog and ReleaseNotes for 0.4.7.5-alpha

Changes in version 0.4.7.5-alpha - 2022-03-25

  This version contains, of what we hope, the final work for congestion

  control paving the way to the stable version. We expect this to be the last

  alpha version of the 0.4.7.x series. Mostly minor bugfixes except one major

  bugfix that changes how Tor behaves with DNS timeouts for Exit relays. As

  always with an alpha, we recommend all relay operators to upgrade from

  previous alpha to this one.

  o Major bugfixes (onion service, congestion control):

    - Fix the onion service upload case where the congestion control

      parameters were not added to the right object. Fixes bug 40586;

      bugfix on 0.4.7.4-alpha.

  o Major bugfixes (relay, DNS):

    - Lower the DNS timeout from 3 attempts at 5 seconds each to 2

      attempts at 1 seconds each. Two new consensus parameters were

      added to control these values. This change should improve observed

      performance under DNS load; see ticket for more details. Fixes bug

      40312; bugfix on 0.3.5.1-alpha.

  o Minor features (control port):

    - Provide congestion control fields on CIRC_BW and STREAM control

      port events, for use by sbws. Closes ticket 40568.

  o Minor features (fallbackdir):

    - Regenerate fallback directories generated on March 25, 2022.

  o Minor features (geoip data):

    - Update the geoip files to match the IPFire Location Database, as

      retrieved on 2022/03/25.

  o Minor bugfixes (DNSPort, dormant mode):

    - A request on the DNSPort now wakes up a dormant tor. Fixes bug

      40577; bugfix on 0.3.5.1-alpha.

  o Minor bugfixes (metrics port, onion service):

    - Fix the metrics with a port label to be unique. Before this, all

      ports of an onion service would be on the same line which violates

      the Prometheus rules of unique labels. Fixes bug 40581; bugfix

      on 0.4.5.1-alpha.

  o Minor bugfixes (onion service congestion control):

    - Avoid a non-fatal assertion failure in the case where we fail to

      set up congestion control on a rendezvous circuit. This could

      happen naturally if a cache entry expired at an unexpected time.

      Fixes bug 40576; bugfix on 0.4.7.4-alpha.

  o Minor bugfixes (onion service, client):

    - Fix a rare but fatal assertion failure due to a guard subsystem

      recursion triggered by the onion service client. Fixes bug 40579;

      bugfix on 0.3.5.1-alpha.

  o Minor bugfixes (relay, overload):

    - Decide whether to signal overload based on a fraction and

      assessment period of ntor handshake drops. Previously, a single

      drop could trigger an overload state, which caused many false

      positives. Fixes bug 40560; bugfix on 0.4.7.1-alpha.

Changes in version 0.4.7.4-alpha - 2022-02-25

  This version contains the negotiation congestion control work which is the

  final part needed before going stable. There are also various bugfixes

  o Minor features (fallbackdir):

    - Regenerate fallback directories generated on March 25, 2022.

  o Minor features (geoip data):

    - Update the geoip files to match the IPFire Location Database,

      as retrieved on 2022/03/25.

  o Major bugfixes (relay, DNS):

    - Lower the DNS timeout from 3 attempts at 5 seconds each to 2 attempts at

      1 seconds each. Two new consensus parameters were added to control these

      values. This change should improve observed performance under DNS load;

      see ticket for more details. Fixes bug 40312; bugfix on

      0.3.5.1-alpha.

  o Minor bugfixes (relay, overload):

    - Decide whether to signal overload based on a fraction and

      assessment period of ntor handshake drops. Previously, a single

      drop could trigger an overload state, which caused many false

      positives. Fixes bug 40560; bugfix on 0.4.7.1-alpha.