We have two sendme.h files at the moment; we should fix that, but
not in this branch.

rl1987 authored 5 years ago and Nick Mathewson committed 5 years ago

Hopefully this will fix CID 1444769.

Comment clarifications now that the code is seperated. It's the same code, but
its doing this for different reasons on each side.

The client side had garbage histograms and deadcode here, too. That code has
been removed.

The tests have also been updated to properly test the intro circ by sending
padding from the relay side to the client, and verifying that both shut down
when padding was up. (The tests previously erroneously tested only the client
side of intro circs, which actually were supposed to be doing nothing).

This just moves the state transition directives into the proper client/relay
side functions. It also allows us to remove some dead-code from the client
side (since the client doesn't send padding).

- Add some more useful logs for future debugging.

- Stop usage of circpad_state_to_string(). It's innacurate.

- Reduce severity and fix up log domain of some logging messages.

Perhaps the machine on the other side is still not done.

As part of our machines, we need to know when a PADDING_NEGOATIATE(D) cell gets
sent out, so we add an event for this.

We are gonna use this function to register our new machine.

Signed-off-by: David Goulet <dgoulet@torproject.org>

To ease debugging of miscount issues, attach vanguards with --loglevel DEBUG
and obtain control port logs (or use any other control port CIRC and
CIRC_MINOR event logging mechanism).

If circuit padding wants to keep a circuit open and pathbias used to ignore
it, pathbias should continue to ignore it.

This may catch other purpose-change related miscounts (such as timeout
measurement, cannibalization, onion service circuit transitions, and
vanguards).

Also test circpad expiry safeguard.

When a circuit is marked for close, check to see if any of our padding
machines want to take ownership of it and continue padding until the machine
hits the END state.

For safety, we also ensure that machines that do not terminate are still
closed as follows: Because padding machine timers are UINT32_MAX in size, if
some sort of network event doesn't happen on a padding-only circuit within
that time, we can conclude it is deadlocked and allow
circuit_expire_old_circuits_clientside() to close it.

If too much network activity happens, then per-machine padding limits can be
used to cease padding, which will cause network cell events to cease, on the
circuit, which will cause circpad to abandon the circuit as per the above time
limit.

Practracker beatings are even more fun when they get caused mid-PR due to a github auto-rebase of a PR

Because github PRs choose the most recent origin/master at the time of the PR
(and for any fixups pushed to a PR later to send to CI), there are tons of
conflicts and unexpected practracker issues.

This means CI can suddenly fail after fixups to a branch that pass locally.

Then CI fails and we have to close and re-open the PR.

We need to check here because otherwise we can try to schedule padding with no
tokens left upon the receipt of a padding event when our bins just became
empty.

Our other tests tested state lengths against padding packets, and token counts
against non-padding packets. This test checks state lengths against
non-padding packets (and also padding packets too), and checks token counts
against padding packets (and also non-padding packets too).

The next three commits are needed to make this test pass (it found 3 bugs).
Yay?