Feature/exit policy

[jstuczyn]

Description

Closes: #4024

Apart from obviously testing the thing, before it can be merged, we need to make sure the following is adjusted to the correct value (i.e. we need to redeploy the website):

nym/common/network-defaults/src/mainnet.rs

Line 31 in 86fcb51

pub const EXIT_POLICY_URL: &str = &*"http://localhost:8001/sample_policy";

edit 25/10/23: it was already updated

what does it do?

as the related ticket describes, it adds a different kind of request filtering to our network requesters. rather than being based on the current allow lists system, it uses a tornull-based exit policy.

right now this is enabled via the with-exit-policy flag (or obviously also via modifying config.toml file), however, soon this will get deprecated and the exit policy will become the default. even further in the future, the allow-list will be completely removed and NRs will all be exclusively running the exit policy.

to see whether particular NR uses the exit policy (and what entires it has there) you can do one of the following:

• attempt to access some url that would normally be disallowed (duh)
• if the NR is embedded in the gateway, you can query it via /api/v1/network-requester/exit-policy endpoint on the nym-node HTTP API
• finally, you can use the mixnet "query" API on NR. (the easiest way to see it, in testing, would be to use this tool: https://github.com/nymtech/nym/blob/130165a7bae532e0174de24dac5838b78dec2552/tools/nym-nr-query/src/main.rs with, for example, cargo run -- -c ../../envs/sandbox.env --provider <provider-address> exit-policy

finally, @tommyv1987 @benedettadavico when testing you can set the EXIT_POLICY environmental variable to any endpoint serving a valid policy file. For my local tests I've just had a dummy sample_policy served with python -m http.server 8001

for the 'real' deployment file, that we will use in mainnet, you can see it here: https://github.com/nymtech/nym-websites/pull/88#issuecomment-1772577284

Checklist:

• added a changelog entry to CHANGELOG.md