feat: idm snooping (#71)

Implement IDM snooping, a new feature that lets you snoop on messages between guests and the host. The feature exposes the IDM packets send and receives
to the API, allowing kratactl to now listen for messages and feed them to a user for debugging purposes.

crates/daemon/src/control.rs

@@ -13,7 +13,8 @@ use krata::{
             control_service_server::ControlService, ConsoleDataReply, ConsoleDataRequest,
             CreateGuestReply, CreateGuestRequest, DestroyGuestReply, DestroyGuestRequest,
             ListGuestsReply, ListGuestsRequest, ReadGuestMetricsReply, ReadGuestMetricsRequest,
-            ResolveGuestReply, ResolveGuestRequest, WatchEventsReply, WatchEventsRequest,
+            ResolveGuestReply, ResolveGuestRequest, SnoopIdmReply, SnoopIdmRequest,
+            WatchEventsReply, WatchEventsRequest,
         },
     },
 };
@@ -88,6 +89,9 @@ impl ControlService for RuntimeControlService {
     type WatchEventsStream =
         Pin<Box<dyn Stream<Item = Result<WatchEventsReply, Status>> + Send + 'static>>;
 
+    type SnoopIdmStream =
+        Pin<Box<dyn Stream<Item = Result<SnoopIdmReply, Status>> + Send + 'static>>;
+
     async fn create_guest(
         &self,
         request: Request<CreateGuestRequest>,
@@ -346,4 +350,18 @@ impl ControlService for RuntimeControlService {
         };
         Ok(Response::new(Box::pin(output) as Self::WatchEventsStream))
     }
+
+    async fn snoop_idm(
+        &self,
+        request: Request<SnoopIdmRequest>,
+    ) -> Result<Response<Self::SnoopIdmStream>, Status> {
+        let _ = request.into_inner();
+        let mut messages = self.idm.snoop();
+        let output = try_stream! {
+            while let Ok(event) = messages.recv().await {
+                yield SnoopIdmReply { from: event.from, to: event.to, packet: Some(event.packet) };
+            }
+        };
+        Ok(Response::new(Box::pin(output) as Self::SnoopIdmStream))
+    }
 }