This proposal implements part of Prop335; it's based on a patch
from Neel Chauhan.
When configured to do so, authorities will assign a MiddleOnly flag
to certain relays. Any relay which an authority gives this flag
will not get Exit, V2Dir, Guard, or HSDir, and might get BadExit if
the authority votes for that one.
AssumeReachable should only be about whether a relay thinks that it
is reachable itself. But previously, we've had it also turn off
reachability checking of _other_ relays on authorities.
(Technically, reachability tests were still run, but we would ignore
the results.)
With this patch, there is a new AuthDirTestReachability option
(default 1) that controls whether authorities run reachability
tests.
Making this change allows us to have test networks where authorities
set AssumeReachable without disabling their reachability testing
entirely.
Closes ticket #34445.
For various reasons, this was a nontrivial movement. There are
several places in the code where we do something like "update the
flags on this routerstatus or node if we're an authority", and at
least one where we pretended to be an authority when we weren't.
The main.c code is responsible for initialization and shutdown;
the mainloop.c code is responsible for running the main loop of Tor.
Splitting the "generic event loop" part of mainloop.c from the
event-loop-specific part is not done as part of this patch.
In dirauth:
* bwauth.c reads and uses bandwidth files
* guardfraction.c reads and uses the guardfraction file
* reachability.c tests relay reachability
* recommend_pkg.c handles the recommended-packages lines.
* recv_descs.c handles fingerprint files and processing incoming
routerinfos that relays upload to us
* voteflag.c computes flag thresholds and sets those thresholds on
routerstatuses when computing votes
In control:
* fmt_serverstatus.c generates the ancient "v1 server status"
format that controllers expect.
In nodelist:
* routerstatus_fmt.c formats routerstatus entries for a consensus,
a vote, or for the controller.
