Fixes a possible root cause of 11553 by only making 64 attempts at
most to pick a circuitID. Previously, we would test every possible
circuit ID until we found one or ran out.
This algorithm succeeds probabilistically. As the comment says:
This potentially causes us to give up early if our circuit ID
space is nearly full. If we have N circuit IDs in use, then we
will reject a new circuit with probability (N / max_range) ^
MAX_CIRCID_ATTEMPTS. This means that in practice, a few percent
of our circuit ID capacity will go unused.
The alternative here, though, is to do a linear search over the
whole circuit ID space every time we extend a circuit, which is
not so great either.
This makes new vs old clients distinguishable, so we should try to
batch it with other patches that do that, like 11438.
Right now this accounts for about 1% of circuits over all, but if you
pick a guard that's running 0.2.3, it will be about 6% of the circuits
running through that guard.
Making sure that every circuit has at least one ntor link means that
we're getting plausibly good forward secrecy on every circuit.
This implements ticket 9777,
The old code had logic to use a shorter path length if we didn't
have enough nodes. But we don't support 2-node networks anwyay.
Fix for #9926. I'm not calling this a bugfix on any particular
version, since a 2-node network would fail to work for you for a lot
of other reasons too, and it's not clear to me when that began, or if
2-node networks would ever have worked.
We need to subtract both the current built circuits *and* the attempted
circuits from the attempt count during scaling, since *both* have already been
counted there.
It seems that some versions of clang that would prefer the
-Wswitch-enum compiler flag to warn about switch statements with
missing enum values, even if those switch statements have a
default.
Fixes bug 8598; bugfix on 0.2.4.10-alpha.
Now that circid_t is 4 bytes long, the default integer promotions will
leave it alone when sizeof(int) == 4, which will leave us formatting an
unsigned as an int. That's technically undefined behavior.
Fixes bug 8447 on bfffc1f0fc. Bug not
in any released Tor.
These seem to have gotten conflicted out of existence while mike was
working on path bias stuff.
Thanks to sysrqb for collecting these in a handy patch.
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.
Also, deprecate the torrc options for the scaling values. It's unlikely anyone
but developers will ever tweak them, even if we provided a single ratio value.
