master
2 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Simone Basso
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b7cc309901
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feat: re-implement the vanilla_tor experiment (#718)
This diff re-implements the vanilla_tor experiment. This experiment was part of the ooni/probe-legacy implementation. The reference issue is https://github.com/ooni/probe/issues/803. We didn't consider the possible improvements mentioned by the https://github.com/ooni/probe/issues/803#issuecomment-598715694 comment, which means we'll need to create a follow-up issue for them. We will then decide whether, when, and how to implement those follow-up measurements either into `vanilla_tor` or into the existing `tor` experiment. This novel `vanilla_tor` implementation emits test_keys that are mostly compatible with the original implementation, however: 1. the `timeout` is a `float64` rather than integer (but the default timeout is an integer, so there are no JSON-visible changes); 2. the `tor_log` string is gone and replaced by the `tor_logs` list of strings, which contains the same information; 3. the definition of `error` has been augmented to include the case in which there is an unknown error; 4. the implementation of vanilla_tor mirrors closely the one of torsf and we have taken steps to make the two implementations as comparable as possible in terms of the generated JSON measurement. The main reason why we replaced `tor_log` with `tor_logs` are: 1. that `torsf` already used that; 2. that reading the JSON is easier with this implementation compared to an implementation where all logs are into the same string. If one is processing the new data format using Python, then it will not be difficult convert `tor_log` to `tor_logs`. In any case, because we extract the most interesting fields (e.g., the percentage of the bootstrap where tor fails), it seems that logs are probably more useful as something you want to read in edge cases (I guess). Also, because we want `torsf` and `vanilla_tor` to have similar JSONs, we renamed `torsf`'s `default_timeout` to `timeout`. This change has little to none real-world impact, because no stable version of OONI Probe has ever shipped a `torsf` producing the `default_timeout` field. Regarding the structure of this diff, we have: 1. factored code to parse tor logs into a separate package; 2. implemented `vanilla_tor` as a stripped down `torsf` and added further changes to ensure compatibility with the previous `vanilla_tor`'s data format; 3. improved `torsf` to merge back the changes in `vanilla_tor`, so the two data formats of the two experiments are as similar as possible. We believe producing as similar as possible data formats helps anyone who's reading measurements generated by both experiments. We have retained/introduced `vanilla_tor`'s `error` field, which is not very useful when one has a more precise failure but is still what `vanilla_tor` used to emit, so it makes sense to also have this field. In addition to changing the implementation, we also updated the specs. As part of our future work, we may want to consider factoring the common code of these two experiments into the same underlying support library. |
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Simone Basso
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85664f1e31
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feat(torsf): collect tor logs, select rendezvous method, count bytes (#683)
This diff contains significant improvements over the previous implementation of the torsf experiment. We add support for configuring different rendezvous methods after the convo at https://github.com/ooni/probe/issues/2004. In doing that, I've tried to use a terminology that is consistent with the names being actually used by tor developers. In terms of what to do next, this diff basically instruments torsf to always rendezvous using domain fronting. Yet, it's also possible to change the rendezvous method from the command line, when using miniooni, which allows to experiment a bit more. In the same vein, by default we use a persistent tor datadir, but it's also possible to use a temporary datadir using the cmdline. Here's how a generic invocation of `torsf` looks like: ```bash ./miniooni -O DisablePersistentDatadir=true \ -O RendezvousMethod=amp \ -O DisableProgress=true \ torsf ``` (The default is `DisablePersistentDatadir=false` and `RendezvousMethod=domain_fronting`.) With this implementation, we can start measuring whether snowflake and tor together can boostrap, which seems the most important thing to focus on at the beginning. Understanding why the bootstrap most often does not converge with a temporary datadir on Android devices remains instead an open problem for now. (I'll also update the relevant issues or create new issues after commit this.) We also address some methodology improvements that were proposed in https://github.com/ooni/probe/issues/1686. Namely: 1. we record the tor version; 2. we include the bootstrap percentage by reading the logs; 3. we set the anomaly key correctly; 4. we measure the bytes send and received (by `tor` not by `snowflake`, since doing it for snowflake seems more complex at this stage). What remains to be done is the possibility of including Snowflake events into the measurement, which is not possible until the new improvements at common/event in snowflake.git are included into a tagged version of snowflake itself. (I'll make sure to mention this aspect to @cohosh in https://github.com/ooni/probe/issues/2004.) |