WEB: Lifecycle + Lane ownership + Diag fixes

Co-Authored-By: brekotis <93345790+brekotis@users.noreply.github.com>

src/web/session.rs

@@ -62,6 +62,22 @@ pub(crate) struct StreamIdentity {
     pub(crate) instance: u64,
 }
 
+/// Exact server-local identity of one carrier-lane incarnation.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub(crate) struct CarrierLaneIdentity {
+    /// Numeric lane identifier carried on the wire.
+    pub(crate) lane_id: u32,
+    /// Monotonic server-local incarnation of that numeric lane.
+    pub(crate) instance: u64,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+struct WebSocketLaneClaim {
+    lane: CarrierLaneIdentity,
+    peer_port: u16,
+    connection_id: Option<u64>,
+}
+
 struct StreamState {
     instance: u64,
     inbound: VecDeque<InboundChunk>,
@@ -144,7 +160,7 @@ struct SessionState {
     carrier_lanes: HashMap<u32, CarrierLane>,
     lane_open_waits: usize,
     next_lane_instance: u64,
-    websocket_lane_reservations: HashMap<u32, u16>,
+    websocket_lane_reservations: HashMap<u32, WebSocketLaneClaim>,
     pending_bytes: usize,
     pending_items: usize,
     pending_control_bytes: usize,
@@ -506,11 +522,14 @@ fn remember_closed(state: &mut SessionState, stream_id: u32, limit: usize) -> Op
     evicted
 }
 
-fn insert_carrier_lane(state: &mut SessionState, lane_id: u32) -> Option<u64> {
+fn insert_carrier_lane(state: &mut SessionState, lane_id: u32) -> Option<CarrierLaneIdentity> {
+    if state.carrier_lanes.contains_key(&lane_id) {
+        return None;
+    }
     let instance = state.next_lane_instance;
     state.next_lane_instance = instance.checked_add(1)?;
     state
         .carrier_lanes
         .insert(lane_id, CarrierLane::new(instance));
-    Some(instance)
+    Some(CarrierLaneIdentity { lane_id, instance })
 }