orin-status: report the CAN interface (up, bus state, frames/s); --can picks it

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DDwfd6Ki8UfG4hK6W5YpJz

src/orin-status/can.rs

@@ -0,0 +1,55 @@
+//! The CAN interface the recorder reads (the PEAK on the OBD port): up or down, frames
+//! per second from the sysfs counter, and the controller's bus state from `ip`. Shown so
+//! a down interface is seen before a capture, not discovered as refused marks.
+
+use std::fs;
+use std::path::Path;
+use std::process::Command;
+use std::time::Instant;
+
+use serde_json::{json, Value};
+
+pub struct Can {
+    iface: String,
+    prev: Option<(Instant, u64)>,
+}
+
+/// Controller state as `ip -j -d link show` reports it: ERROR-ACTIVE, ERROR-WARNING,
+/// ERROR-PASSIVE, BUS-OFF or STOPPED.
+fn bus_state(iface: &str) -> Option<String> {
+    let out = Command::new("ip").args(["-j", "-d", "link", "show", iface]).output().ok()?;
+    let v: Value = serde_json::from_slice(&out.stdout).ok()?;
+    Some(v[0]["linkinfo"]["info_data"]["state"].as_str()?.to_string())
+}
+
+impl Can {
+    pub fn new(iface: &str) -> Self {
+        Can { iface: iface.to_string(), prev: None }
+    }
+
+    pub fn read(&mut self, out: &mut Vec<(&'static str, Value)>) {
+        let dir = Path::new("/sys/class/net").join(&self.iface);
+        if !dir.exists() {
+            self.prev = None;
+            out.push(("can_up", json!(false)));
+            out.push(("can_bus_state", json!("absent")));
+            return;
+        }
+        // operstate is "up" for an interface that is up, "unknown" on some CAN drivers: use the flags.
+        let flags = fs::read_to_string(dir.join("flags")).ok().and_then(|s| u32::from_str_radix(s.trim().trim_start_matches("0x"), 16).ok());
+        out.push(("can_up", json!(flags.is_some_and(|f| f & 1 != 0))));
+        if let Some(state) = bus_state(&self.iface) {
+            out.push(("can_bus_state", json!(state)));
+        }
+        let rx: Option<u64> = fs::read_to_string(dir.join("statistics/rx_packets")).ok().and_then(|s| s.trim().parse().ok());
+        if let Some(rx) = rx {
+            let now = Instant::now();
+            if let Some((t, p)) = self.prev.replace((now, rx)) {
+                let dt = now.duration_since(t).as_secs_f64();
+                if dt > 0.0 && rx >= p {
+                    out.push(("can_rx_fps", json!(((rx - p) as f64 / dt).round())));
+                }
+            }
+        }
+    }
+}

src/orin-status/main.rs

@@ -1,7 +1,7 @@
 //! orin-status — the Orin's own health on the bus, once a second.
 //!
 //! Temperatures, CPU and GPU load, the shared memory pool, module power, the fan,
-//! network links (WiFi, LTE, the USB link to the tablet) and the UPS battery, each
+//! network links (WiFi, LTE, the USB link to the tablet), the CAN interface and the UPS battery, each
 //! as an envelope on `yukart/host/<signal>`, retained. Names and units come from
 //! contracts' `signals.json` (source `host`).
 //!
@@ -9,6 +9,7 @@
 //! it stale, which is the honest picture. The service's own state goes on
 //! `yukart/system/orin-status`, with a last will for when it vanishes.
 
+mod can;
 mod host;
 mod net;
 mod ups;
@@ -25,6 +26,7 @@ use serde_json::{json, Value};
 const USAGE: &str = "\
 usage: orin-status [options]
   --broker HOST:PORT   MQTT broker                 (127.0.0.1:1883)
+  --can IFACE          CAN interface to report     (can_pcan)
   --i2c DEV            I²C bus of the UPS INA219   (/dev/i2c-7)
   --ups-addr ADDR      INA219 address, hex         (41)
   --once               print one reading as JSON and exit (no broker)";
@@ -57,6 +59,7 @@ fn units() -> std::collections::HashMap<String, String> {
 struct Sources {
     host: host::Host,
     net: net::Net,
+    can: can::Can,
     ups: ups::Ups,
 }
 
@@ -67,6 +70,7 @@ impl Sources {
         let mut failed = Vec::new();
         self.host.read(&mut out);
         self.net.read(&mut out);
+        self.can.read(&mut out);
         if !self.ups.read(&mut out) {
             failed.push("ups");
         }
@@ -77,6 +81,7 @@ impl Sources {
 fn main() -> ExitCode {
     let mut broker = "127.0.0.1:1883".to_string();
     let mut i2c = "/dev/i2c-7".to_string();
+    let mut can_iface = "can_pcan".to_string();
     let mut addr: u16 = 0x41;
     let mut once = false;
     let mut args = std::env::args().skip(1);
@@ -85,6 +90,7 @@ fn main() -> ExitCode {
             "--once" => once = true,
             "--broker" => broker = args.next().unwrap_or_default(),
             "--i2c" => i2c = args.next().unwrap_or_default(),
+            "--can" => can_iface = args.next().unwrap_or_default(),
             "--ups-addr" => match args.next().and_then(|v| u16::from_str_radix(v.trim_start_matches("0x"), 16).ok()) {
                 Some(v) => addr = v,
                 None => {
@@ -100,7 +106,7 @@ fn main() -> ExitCode {
     }
 
     let units = units();
-    let mut src = Sources { host: host::Host::discover(), net: net::Net::start(), ups: ups::Ups::new(&i2c, addr) };
+    let mut src = Sources { host: host::Host::discover(), net: net::Net::start(), can: can::Can::new(&can_iface), ups: ups::Ups::new(&i2c, addr) };
 
     if once {
         src.read(); // rates and CPU load need two readings