Fix indefinite port_settings_* failures

Cargo.toml

@@ -53,7 +53,7 @@ omicron-common = { git = "https://github.com/oxidecomputer/omicron", branch= "ma
 oximeter = { git = "https://github.com/oxidecomputer/omicron", branch = "main" }
 oximeter-producer = { git = "https://github.com/oxidecomputer/omicron", branch = "main" }
 oximeter-instruments = { git = "https://github.com/oxidecomputer/omicron", branch = "main", default-features = false, features = ["kstat"] }
-oxnet = { version = "0.1.6", default-features = false, features = ["schemars", "serde"] }
+oxnet = { version = "0.1.7", default-features = false, features = ["schemars", "serde"] }
 propolis = { git = "https://github.com/oxidecomputer/propolis" }
 smf = { git = "https://github.com/illumos/smf-rs" }
 slog-error-chain = { git = "https://github.com/oxidecomputer/slog-error-chain", branch = "main" }

asic/src/chaos/mod.rs

@@ -9,6 +9,7 @@ use serde::{Deserialize, Serialize};
 use slog::Logger;
 use std::collections::HashMap;
 use std::sync::Mutex;
+use std::sync::OnceLock;
 use tokio::sync::mpsc;
 
 #[cfg(feature = "multicast")]
@@ -344,6 +345,7 @@ pub struct Handle {
     ports: Mutex<HashMap<PortHdl, Port>>,
     config: AsicConfig,
     log: Logger,
+    updates: OnceLock<mpsc::UnboundedSender<PortUpdate>>,
 }
 
 impl Handle {
@@ -353,6 +355,7 @@ impl Handle {
             ports: Mutex::new(HashMap::new()),
             config: config.clone(),
             log: log.clone(),
+            updates: OnceLock::new(),
         })
     }
     /// Chaos ASICs always report as a model.
@@ -494,6 +497,22 @@ impl AsicOps for Handle {
         unfurl!(self, port_enable_set);
         let mut ports = self.ports.lock().unwrap();
         get_port_mut(&mut ports, port_hdl)?.enabled = val;
+
+        let Some(chan) = self.updates.get() else {
+            return Ok(());
+        };
+
+        let asic_port_id = self.port_to_asic_id(port_hdl)?;
+        let r1 = chan.send(PortUpdate::Enable { asic_port_id, enabled: val });
+        let r2 = chan.send(PortUpdate::LinkUp { asic_port_id, linkup: val });
+
+        if r1.is_err() || r2.is_err() {
+            return Err(AsicError::Internal(
+                "PortUpdate tx failed. That rx chan should never be dropped."
+                    .to_string(),
+            ));
+        }
+
         Ok(())
     }
 
@@ -579,9 +598,12 @@ impl AsicOps for Handle {
 
     fn register_port_update_handler(
         &self,
-        _tx_channel: mpsc::UnboundedSender<PortUpdate>,
+        tx_channel: mpsc::UnboundedSender<PortUpdate>,
     ) -> AsicResult<()> {
         unfurl!(self, register_port_update_handler);
+        if self.updates.set(tx_channel).is_err() {
+            return Err(AsicError::Exists);
+        }
         Ok(())
     }
 

common/Cargo.toml

@@ -6,6 +6,7 @@ edition = "2024"
 
 [features]
 multicast = []
+test-utils = []
 
 [dependencies]
 anyhow.workspace = true