optimize: do not prepare noise for non-receivers

mixnet/dissemination/src/iteration.rs

@@ -136,7 +136,7 @@ fn relay_messages(
     // Collect messages to relay
     let mut all_msgs_to_relay: Vec<Vec<(NodeId, Message<MessageId>)>> = Vec::new();
     for node in nodes.iter_mut() {
-        all_msgs_to_relay.push(node.read_queues());
+        all_msgs_to_relay.push(node.read_queues(None));
     }
 
     // Relay the messages

mixnet/ordering/src/iteration.rs

@@ -280,7 +280,7 @@ impl AllMessagesToRelay {
     fn new(mixnodes: &mut [Node<DataMessage>]) -> Self {
         let mut all_msgs_to_relay = Vec::with_capacity(mixnodes.len());
         for node in mixnodes.iter_mut() {
-            all_msgs_to_relay.push((node.id, node.read_queues()));
+            all_msgs_to_relay.push((node.id, node.read_queues(Some(RECEIVER_NODE_ID))));
         }
         Self(all_msgs_to_relay)
     }

mixnet/protocol/src/node.rs

@@ -87,10 +87,25 @@ where
         first_received
     }
 
-    pub fn read_queues(&mut self) -> MessagesToRelay<M> {
+    pub fn read_queues(&mut self, noise_receiver: Option<NodeId>) -> MessagesToRelay<M> {
         let mut msgs_to_relay: MessagesToRelay<M> = Vec::with_capacity(self.queues.len());
         self.queues.iter_mut().for_each(|(node_id, queue)| {
-            msgs_to_relay.push((*node_id, queue.pop()));
+            let msg = queue.pop();
+            match msg {
+                Message::Data(_) => {
+                    msgs_to_relay.push((*node_id, msg));
+                }
+                Message::Noise => match noise_receiver {
+                    Some(noise_receiver) => {
+                        if *node_id == noise_receiver {
+                            msgs_to_relay.push((*node_id, msg));
+                        }
+                    }
+                    None => {
+                        msgs_to_relay.push((*node_id, msg));
+                    }
+                },
+            }
         });
         msgs_to_relay
     }