This check makes it so we can reach "done" without setting "conn",
and so the "if (conn)" check will not be redundant, and so coverity
won't complain. Fixes CID 1422205. Not actually a bug.
Our mock network put all the guards on the same IPv4 address, which
doesn't fly when we start applying EnforceDistinctSubnets. So in
this commit, I disable EnforceDistinctSubnets when running the old
guard_restriction_t test.
This commit also adds a regression test for #22753.
This is an important thing I hadn't considered when writing prop271:
sometimes you have to restrict what guard you use for a particular
circuit. Most frequently, that would be because you plan to use a
certain node as your exit, and so you can't choose that for your
guard.
This change means that the upgrade-waiting-circuits algorithm needs
a slight tweak too: circuit A cannot block circuit B from upgrading
if circuit B needs to follow a restriction that circuit A does not
follow.
George pointed out that (-1,0,1) for (never usable, maybe usable
later, usable right now) was a pretty rotten convention that made
the code harder to read.
This includes:
* making bridge_info_t exposed but opaque
* allowing guards where we don't know an identity
* making it possible to learn the identity of a guard
* creating a guard that lacks a node_t
* remembering a guard's address and port.
* Looking up a guard by address and port.
* Only enforcing the rule that we need a live consensus to update
the "listed" status for guards when we are not using bridges.
Currently, this code doesn't actually have the contexts behave
differently, (except for the legacy context), but it does switch
back and forth between them nicely.
Some of these will get torrc options to override them too; this
is just the mechanical conversion.
Also, add documentation for a couple of undocumented (but now used)
parameters.
To do this, it makes sense to treat legacy guards as a separate
guard_selection_t *, and handle them separately. This also means we
add support here for having multiple guard selections.
Note that we don't persist pathbias information yet; that will take
some refactoring.
