Refactor `mullvad-relay-selector`

Implement a system built on 'queries' for selecting appropriate relays.
A query is a set of constraints which dictates which relay(s) that *can*
be chosen by the relay selector.

The user's settings can naturally be expressed as a query. The semantics
of merging two queries in a way that always prefer user settings is
defined by the new `Intersection` trait.

Split `mullvad-relay-selector` into several modules:

- `query.rs`: Definition of a query on different types of relays. This
module is integral to the new API of `mullvad-relay-selector`
- `matcher.rs`: Logic for filtering out candidate relays based on a
query.
- `detailer.rs`: Logic for deriving connection details for the selected
relay.
- `tests/`: Integration tests for the new relay selector. These tests
only use the public APIs of `RelaySelector` and make sure that the
output matches the expected output in different scenarios.

2 files changed, 2 insertions, 1 deletions

diff --git a/talpid-core/src/tunnel_state_machine/connecting_state.rs b/talpid-core/src/tunnel_state_machine/connecting_state.rs
index 71a88e64fb..96800f8a0d 100644
--- a/talpid-core/src/tunnel_state_machine/connecting_state.rs
+++ b/talpid-core/src/tunnel_state_machine/connecting_state.rs
@@ -69,7 +69,7 @@ impl ConnectingState {
         match shared_values.runtime.block_on(
             shared_values
                 .tunnel_parameters_generator
-                .generate(retry_attempt),
+                .generate(retry_attempt, shared_values.connectivity.has_ipv6()),
         ) {
             Err(err) => {
                 ErrorState::enter(shared_values, ErrorStateCause::TunnelParameterError(err))
diff --git a/talpid-core/src/tunnel_state_machine/mod.rs b/talpid-core/src/tunnel_state_machine/mod.rs
index 164b1741ad..02bd2bdbff 100644
--- a/talpid-core/src/tunnel_state_machine/mod.rs
+++ b/talpid-core/src/tunnel_state_machine/mod.rs
@@ -417,6 +417,7 @@ pub trait TunnelParametersGenerator: Send + 'static {
     fn generate(
         &mut self,
         retry_attempt: u32,
+        ipv6: bool,
     ) -> Pin<Box<dyn Future<Output = Result<TunnelParameters, ParameterGenerationError>>>>;
 }