If any circuits were opened during a scaling event, we were scaling attempts
and successes by different amounts. This leads to rounding error.
The fix is to record how many circuits are in a state that hasn't been fully
counted yet, and subtract that before scaling, and add it back afterwords.
Since they use RELAY_EARLY (which can be seen by all hops on the path),
it's not safe to say they actually count as a successful use.
There are also problems with trying to allow them to finish extending due to
the circuit purpose state machine logic. It is way less complicated (and
possibly more semantically coherent) to simply wait until we actually try to
do something with them before claiming we 'used' them.
Also, we shouldn't call timed out circuits 'used' either, for semantic
consistency.
An adversary could let the first stream request succeed (ie the resolve), but
then tag and timeout the remainder (via cell dropping), forcing them on new
circuits.
Rolling back the state will cause us to probe such circuits, which should lead
to probe failures in the event of such tagging due to either unrecognized
cells coming in while we wait for the probe, or the cipher state getting out
of sync in the case of dropped cells.
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.
The implementation is pretty straightforward: parse_extended_hostname() is
modified to drop any leading components from an address like
'foo.aaaaaaaaaaaaaaaa.onion'.
This is an automatically generated commit, from the following perl script,
run with the options "-w -i -p".
s/smartlist_string_num_isin/smartlist_contains_int_as_string/g;
s/smartlist_string_isin((?:_case)?)/smartlist_contains_string$1/g;
s/smartlist_digest_isin/smartlist_contains_digest/g;
s/smartlist_isin/smartlist_contains/g;
s/digestset_isin/digestset_contains/g;
In 6fbdf635 we added a couple of statements like:
if (test) {
...
};
The extraneous semicolons there get flagged as worrisome empty
statements by the cparser library, so let's fix them.
Patch by Christian Grothoff; fixes bug 7115.
Otherwise, it's possible to create streams or circuits with these
bogus IDs, leading to orphaned circuits or streams, or to ones that
can cause bandwidth DOS problems.
Fixes bug 7889; bugfix on all released Tors.
In general, if we tried to use a circ for a stream, but then decided to place
that stream on a different circuit, we need to probe the original circuit
before deciding it was a "success".
We also need to do the same for cannibalized circuits that go unused.
