Start on a changelog for 0.3.1.1-alpha

changes/bug12062

-  o Minor bugfixes (hibernation, bandwidth accounting, shutdown):
-
-    - When hibernating, do not attempt to launch DNS checks. Fixes a
-      case of bug 12062; bugfix on 0.1.2.2-alpha.
-
-    - Resolve several bugs related to descriptor fetching on bridge
-      clients with bandwidth accounting enabled. (This combination is
-      not recommended!) Fixes a case of bug 12062; bugfix on
-      0.2.0.3-alpha.
-
-    - When hibernating, do not try to upload or download
-      descriptors. Fixes a case of bug 12062; bugfix on 0.0.9pre5.
-
-    - Do not attempt to launch self-reachability tests when entering
-      hibernation. Fixes a base of bug 12062; bugfix on 0.0.9pre5.
-

changes/bug13837

-  o Major features (Onion Services):
-    - Provide torrc options to pin the second and third hops of onion service
-      circuits to a list of nodes. The option HSLayer2Guards pins the second hop,
-      and the option HSLayer3Guards pins the third hop. Closes ticket 13837.

changes/bug20942

-  o Minor features (fallback directory mirrors):
-    - Reject any fallback directory mirror that serves an expired consensus.
-      Implements ticket 20942, patch by "minik".

changes/bug21074_downgrade

-  o Minor bugfixes (OSX):
-    - Don't exit the Tor process if setrlimit() fails to change the file
-      limit (which can happen sometimes on some versions of OSX). Fixes
-      bug 21074; bugfix on 0.0.9pre5.

changes/bug22605

-  o Minor bugfixes (linux seccomp2 sandbox):
-    - When running with the sandbox enabled, reload configuration files
-      correctly even when %include was used. Previously we
-      would crash. Fixes bug 22605; bugfix on 0.3.1.
-      Patch from Daniel Pinto.

changes/bug22798

-  o Minor features (windows, performance):
-    - Improve performance on Windows Vista and Windows 7 by adjusting TCP send
-      window size according to the recommendation from
-      SIO_IDEAL_SEND_BACKLOG_QUERY.  Closes ticket 22798. Patch from Vort.

changes/bug22907

-  o Documentation:
-    - Add documentation on how to build tor with Rust dependencies without
-      requiring being online.  Closes ticket 22907; bugfix on tor-0.3.0.3-alpha.

changes/bug23100

-  o Minor bugfixes (Performance):
-    - Use hidden service circuits (and other circuits longer than 3 hops)
-      to calculate a circuit build timeout. Previously, Tor only calculated
-      its build timeout based on circuits that planned to be exactly 3 hops
-      long. With this change, we include measurements from all circuits at
-      the point where they complete their third hop.  Fixes bug 23100;
-      bugfix on 0.2.2.2-alpha.

changes/bug23101

-  o Minor features (Performance):
-    - Support predictive circuit building for onion service circuits with
-      multiple layers of guards. Closes ticket 23101.

changes/bug23114

-  o Minor bugfixes (Performance):
-    - Consider circuits for timeout as soon as they complete a hop. This
-      is more accurate than applying the timeout in circuit_expire_building()
-      because that function is only called once per second, which is now
-      too slow for typical timeouts on the current network. Fixes bug 23114;
-      bugfix on 0.2.2.2-alpha.

changes/bug23571

-  o Minor bugfixes (hibernation):
-    - When hibernating, close connections normally and allow them to flush.
-      Fixes bug 23571; bugfix on 0.2.4.7-alpha. Also fixes bug 7267.

changes/bug23826-23828

-  o Major features (IPv6, directory documents):
-    - Add consensus method 27, which adds IPv6 ORPorts to the microdesc
-      consensus. This makes it easier for IPv6 clients to bootstrap and
-      choose reachable entry guards.
-      Implements 23826.
-    - Add consensus method 28, which removes IPv6 ORPorts from
-      microdescriptors. Now that there are IPv6 ORPorts in the microdesc
-      consensus, they are redundant in microdescs. This change is compatible
-      with tor clients on 0.2.8.x and later. (0.2.8.x introduced client IPv6
-      bootstrap and guard support.)
-      Implements 23828.
-    - Expand the documentation for AuthDirHasIPv6Connectivity when it is set
-      by different numbers of authorities.
-      Fixes 23870 on 0.2.4.1-alpha.

changes/bug23827

-  o Minor feature (IPv6):
-    - When a consensus has IPv6 ORPorts, make IPv6-only clients use them,
-      rather than waiting to download microdescriptors.
-      Implements 23827.
-    - Make IPv6-only clients wait for microdescs for relays, even if we were
-      previously using descriptors (or were using them as a bridge) and have
-      a cached descriptor for them.
-      Implements 23827.

changes/bug23848

-  o Minor features (embedding):
-    - On most errors that would cause Tor to exit, it now tries to return
-      from the tor_main() function, rather than calling the system exit()
-      function.  Most users won't notice a difference here, but it should
-      make a significant difference on platforms that try to run Tor inside
-      a separate thread: they should now be able to survive Tor's exit
-      conditions rather than having Tor shut down the entire process.
-      Closes ticket 23848.

changes/bug23953

-  o Minor features (performance):
-    - Use stdatomic.h where available, rather than mutexes, to implement
-      atomic_counter_t. Closes ticket 23953.

changes/bug24119

-  o Code simplification and refactoring:
-    - Rewrite channel_rsa_id_group_set_badness to reduce temporary memory
-      allocations with large numbers of OR connections (e.g. relays). Closes
-      ticket 24119.

changes/bug24137

-  o Minor bugfixes (Private Networks):
-   - Give out Exit flags in bootstrapping networks. Fixes bug 24137;
-     bugfix on 0.2.3.1-alpha.

changes/bug24318

-  o Documentation:
-    - Clarify the behavior of RelayBandwidth{Rate,Burst} with client traffic.
-      Closes ticket 24318.

changes/bug24337

-  o Minor features (defensive programming):
-    - Most of the functions in Tor that free objects have been replaced
-      with macros that free the objects and set the corresponding pointers
-      to NULL. This change should help prevent a large class of dangling
-      pointer bugs. Closes ticket 24337.
-
-    - Where possible, the tor_free() macro now only evaluates its input once.
-      Part of ticket 24337.