This is safe, because no entry_guard_t ever outlives its
guard_selection_t.
I want this because now that multiple guard selections can be active
during one tor session, we should make sure that any information we
register about guards is with respect to the selection that they came
from.
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.
This patch doesn't cover every case; omitted cases are marked with
"XXXX prop271", as usual. It leaves both the old interface and the
new interface for guard status notification, since they don't
actually work in the same way: the new API wants to be told when a
circuit has failed or succeeded, whereas the old API wants to know
when a channel has failed or succeeded.
I ran into some trouble with directory guard stuff, since when we
pick the directory guard, we don't actually have a circuit to
associate it with. I solved that by allowing guard states to be
associated with directory connections, not just circuits.
Here we add a little bit of state to origin circuits, and set up
the necessary functions for the circuit code to call in order to
find guards, use guards, and decide when circuits can be used.
There's also an incomplete function for the hard part of the
circuit-maintenance code, where we figure out whether any waiting
guards are ready to become usable.
(This patch finally uses the handle.c code to make safe handles to
entry_guard_t objects, so that we are allowed to free an
entry_guard_t without checking whether any origin_circuit_t is
holding a reference to it.)
This code handles:
* Maintaining the sampled set, the filtered set, and the
usable_filtered set.
* Maintaining the confirmed and primary guard lists.
* Picking guards for circuits, and updating guard state when
circuit state changes.
Additionally, I've done code structure movement: even more constants
and structures from entrynodes.c have become ENTRYNODES_PRIVATE
fields of entrynodes.h.
I've also included a bunch of documentation and a bunch of unit
tests. Coverage on the new code is pretty high.
I've noted important things to resolve before this branch is done
with the /XXXX.*prop271/ regex.
The previous commit, in moving a bunch of functions to bridges.c,
broke compilation because bridges.c required two entry points to
entrynodes.c it didn't have.
This patch is just:
* Code movement
* Adding headers here and there as needed
* Adding a bridges_free_all() with a call to it.
It breaks compilation, since the bridge code needed to make exactly
2 calls into entrynodes.c internals. I'll fix those in the next
commit.
The encoding code is very straightforward. The decoding code is a
bit tricky, but clean-ish. The sampling code is untested and
probably needs more work.
This was a relatively mechanical change. First, I added an accessor
function for the pathbias-state field of a guard. Then I did a
search-and-replace in circpathbias.c to replace "guard->pb." with
"pb->". Finally, I made sure that "pb" was declared whenever it was
needed.
The entry_guard_t structure should really be opaque, so that we
can change its contents and have the rest of Tor not care.
This commit makes it "mostly opaque" -- circpathbias.c can still see
inside it. (I'm making circpathbias.c exempt since it's the only
part of Tor outside of entrynodes.c that made serious use of
entry_guard_t internals.)
Clients that use bridges were ignoring their cached microdesc-flavor
consensus files, because they only thought they should use the microdesc
flavor once they had a known-working bridge that could offer microdescs,
and at first boot no bridges are known-working.
This bug caused bridge-using clients to download a new microdesc consensus
on each startup.
Fixes bug 20269; bugfix on 0.2.3.12-alpha.
Regardless of the setting of ExtendAllowPrivateAddresses.
This fixes a bug with pluggable transports that ignore the
(potentially private) address in their bridge line.
Fixes bug 18517; bugfix on 23b088907f in tor-0.2.8.1-alpha.
Most of these are simple. The only nontrivial part is that our
pattern for using ENUM_BF was confusing doxygen by making declarations
that didn't look like declarations.
Now we can specify to skip bridges that wouldn't be able to answer the
type of dir fetch we're launching.
It's still the responsibility of the rest of the code to prevent us from
launching a given dir fetch if we have no bridges that could handle it.
Now as we move into a future where most bridges can handle microdescs
we will generally find ourselves using them, rather than holding back
just because one of our bridges doesn't use them.
Path use bias measures how often we can actually succeed using the circuits we
actually try to use. It is a subset of path bias accounting, but it is
computed as a separate statistic because the rate of client circuit use may
vary depending on use case.
Turns out there's more than one way to block a tagged circuit.
This seems to successfully handle all of the normal exit circuits. Hidden
services need additional tweaks, still.
