chore: fix clippy warnings about HashMap iteration (#10661)

Not quite sure how these didn't get picked up by CI but they showed in
my local IDE.

---------

Signed-off-by: Thomas Eizinger <thomas@eizinger.io>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

rust/connlib/phoenix-channel/src/lib.rs

@@ -4,7 +4,7 @@ mod get_user_agent;
 mod login_url;
 
 use anyhow::{Context as _, Result};
-use std::collections::{HashMap, VecDeque};
+use std::collections::{BTreeMap, VecDeque};
 use std::net::{IpAddr, SocketAddr, ToSocketAddrs as _};
 use std::sync::Arc;
 use std::time::{Duration, Instant};
@@ -48,7 +48,7 @@ pub struct PhoenixChannel<TInitReq, TInboundMsg, TFinish> {
 
     _phantom: PhantomData<TInboundMsg>,
 
-    pending_join_requests: HashMap<OutboundRequestId, Instant>,
+    pending_join_requests: BTreeMap<OutboundRequestId, Instant>,
 
     // Stored here to allow re-connecting.
     url_prototype: Secret<LoginUrl<TFinish>>,

rust/connlib/snownet/src/node/connections.rs

@@ -1,5 +1,5 @@
 use std::{
-    collections::{BTreeMap, HashMap, VecDeque},
+    collections::{BTreeMap, VecDeque},
     fmt,
     hash::Hash,
     iter,
@@ -23,9 +23,9 @@ pub struct Connections<TId, RId> {
 
     established_by_wireguard_session_index: BTreeMap<usize, TId>,
 
-    disconnected_ids: HashMap<TId, Instant>,
-    disconnected_public_keys: HashMap<[u8; 32], Instant>,
-    disconnected_session_indices: HashMap<usize, Instant>,
+    disconnected_ids: BTreeMap<TId, Instant>,
+    disconnected_public_keys: BTreeMap<[u8; 32], Instant>,
+    disconnected_session_indices: BTreeMap<usize, Instant>,
 }
 
 impl<TId, RId> Default for Connections<TId, RId> {
@@ -359,9 +359,9 @@ pub struct UnknownConnection {
 }
 
 impl UnknownConnection {
-    fn by_id<TId>(id: TId, disconnected_ids: &HashMap<TId, Instant>, now: Instant) -> Self
+    fn by_id<TId>(id: TId, disconnected_ids: &BTreeMap<TId, Instant>, now: Instant) -> Self
     where
-        TId: fmt::Display + Eq + Hash,
+        TId: fmt::Display + Eq + Ord,
     {
         Self {
             id: id.to_string(),
@@ -372,7 +372,7 @@ impl UnknownConnection {
         }
     }
 
-    fn by_index(id: usize, disconnected_indices: &HashMap<usize, Instant>, now: Instant) -> Self {
+    fn by_index(id: usize, disconnected_indices: &BTreeMap<usize, Instant>, now: Instant) -> Self {
         Self {
             id: id.to_string(),
             kind: "index",
@@ -384,7 +384,7 @@ impl UnknownConnection {
 
     fn by_public_key(
         key: [u8; 32],
-        disconnected_public_keys: &HashMap<[u8; 32], Instant>,
+        disconnected_public_keys: &BTreeMap<[u8; 32], Instant>,
         now: Instant,
     ) -> Self {
         Self {

rust/connlib/tunnel/src/tests/sim_client.rs

@@ -483,7 +483,7 @@ pub struct RefClient {
 
     /// The expected TCP connections.
     #[debug(skip)]
-    pub(crate) expected_tcp_connections: HashMap<(IpAddr, Destination, SPort, DPort), ResourceId>,
+    pub(crate) expected_tcp_connections: BTreeMap<(IpAddr, Destination, SPort, DPort), ResourceId>,
 
     /// The expected UDP DNS handshakes.
     #[debug(skip)]
@@ -703,10 +703,6 @@ impl RefClient {
         }
     }
 
-    #[expect(
-        clippy::disallowed_methods,
-        reason = "We don't care about the ordering of the expected TCP connections."
-    )]
     pub(crate) fn expected_resource_status(
         &self,
         has_failed_tcp_connection: impl Fn((SPort, DPort)) -> bool,
@@ -1223,10 +1219,6 @@ impl RefClient {
             .contains_key(&(src, dst, sport, dport))
     }
 
-    #[expect(
-        clippy::disallowed_methods,
-        reason = "Iteration order does not matter here."
-    )]
     pub(crate) fn tcp_connection_tuple_to_resource(
         &self,
         resource: ResourceId,

rust/connlib/tunnel/src/tests/transition.rs

@@ -144,6 +144,28 @@ pub(crate) enum Destination {
     IpAddr(IpAddr),
 }
 
+impl Ord for Destination {
+    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
+        match (self, other) {
+            (
+                Destination::DomainName { name: left, .. },
+                Destination::DomainName { name: right, .. },
+            ) => left.cmp(right),
+            (Destination::IpAddr(left), Destination::IpAddr(right)) => left.cmp(right),
+
+            // These are according to variant order.
+            (Destination::DomainName { .. }, Destination::IpAddr(_)) => std::cmp::Ordering::Less,
+            (Destination::IpAddr(_), Destination::DomainName { .. }) => std::cmp::Ordering::Greater,
+        }
+    }
+}
+
+impl PartialOrd for Destination {
+    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
 impl Eq for Destination {}
 
 impl std::hash::Hash for Destination {

rust/relay/server/src/server.rs

@@ -54,7 +54,7 @@ pub struct Server<R> {
     public_address: IpStack,
 
     /// All client allocations, indexed by client's socket address.
-    allocations: HashMap<ClientSocket, Allocation>,
+    allocations: BTreeMap<ClientSocket, Allocation>,
     clients_by_allocation: HashMap<AllocationPort, ClientSocket>,
     /// Redundant mapping so we can look route data with a single lookup.
     channel_and_client_by_port_and_peer: