woah

so what are these? auto gc and typed observation (because some flett shit is depending on ts)

Co-authored-by: Copilot <[email protected]>

wakey-linux/src/observations.rs

@@ -0,0 +1,579 @@
+use std::io::{self, ErrorKind};
+use std::net::IpAddr;
+use std::path::{Path, PathBuf};
+use std::time::{SystemTime, UNIX_EPOCH};
+
+use macaddr::MacAddr;
+use serde::{Deserialize, Serialize};
+
+const DEFAULT_MAC_NAME_CACHE: &str = "/tmp/wakey_mac_names.json";
+const DEFAULT_OBSERVATION_STORE: &str = "/tmp/wakey_observations.json";
+const MAC_NAME_CACHE_ENV: &str = "WAKEY_MAC_NAME_CACHE";
+const OBSERVATION_STORE_ENV: &str = "WAKEY_OBSERVATION_STORE";
+
+fn now_unix() -> u64 {
+    SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .map(|duration| duration.as_secs())
+        .unwrap_or(0)
+}
+
+pub(crate) fn mac_name_cache_path() -> PathBuf {
+    configured_path(MAC_NAME_CACHE_ENV, DEFAULT_MAC_NAME_CACHE)
+}
+
+pub(crate) fn observation_store_path() -> PathBuf {
+    configured_path(OBSERVATION_STORE_ENV, DEFAULT_OBSERVATION_STORE)
+}
+
+fn configured_path(env_key: &str, default: &str) -> PathBuf {
+    std::env::var_os(env_key)
+        .filter(|value| !value.is_empty())
+        .map(PathBuf::from)
+        .unwrap_or_else(|| PathBuf::from(default))
+}
+
+#[derive(Debug, Clone, Default, Serialize, Deserialize)]
+pub struct LocalObservationStore {
+    #[serde(default)]
+    pub dhcp_clients: std::collections::BTreeMap<String, ObservedDhcpClient>,
+    #[serde(default)]
+    pub neighbors: std::collections::BTreeMap<String, ObservedNeighbor>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ObservedDhcpClient {
+    pub mac: String,
+    pub ip: Option<IpAddr>,
+    pub hostname: Option<String>,
+    pub first_seen_unix: u64,
+    pub last_seen_unix: u64,
+    pub last_action: String,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ObservedNeighbor {
+    pub key: String,
+    pub mac: Option<String>,
+    pub ip: Option<IpAddr>,
+    pub first_seen_unix: u64,
+    pub last_seen_unix: u64,
+    pub last_action: String,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct LocalDeviceObservation {
+    pub kind: String,
+    pub action: String,
+    pub mac: Option<String>,
+    pub ip: Option<IpAddr>,
+    pub hostname: Option<String>,
+    pub first_seen_unix: u64,
+    pub last_seen_unix: u64,
+}
+
+/// Load the MAC-to-name cache used to preserve useful names across lease churn.
+pub async fn load_mac_name_cache() -> io::Result<std::collections::BTreeMap<String, String>> {
+    load_mac_name_cache_from_path(mac_name_cache_path()).await
+}
+
+pub async fn load_mac_name_cache_from_path(
+    path: impl AsRef<Path>,
+) -> io::Result<std::collections::BTreeMap<String, String>> {
+    match tokio::fs::read_to_string(path).await {
+        Ok(s) => serde_json::from_str(&s).map_err(io::Error::other),
+        Err(e) if e.kind() == ErrorKind::NotFound => Ok(Default::default()),
+        Err(e) => Err(e),
+    }
+}
+
+/// Persist the MAC-to-name cache back to disk.
+async fn save_mac_name_cache(map: &std::collections::BTreeMap<String, String>) -> io::Result<()> {
+    save_mac_name_cache_to_path(mac_name_cache_path(), map).await
+}
+
+pub(super) async fn save_mac_name_cache_to_path(
+    path: impl AsRef<Path>,
+    map: &std::collections::BTreeMap<String, String>,
+) -> io::Result<()> {
+    let s = serde_json::to_string(map).map_err(io::Error::other)?;
+    let _ = tokio::fs::write(path, s).await;
+    Ok(())
+}
+
+pub async fn load_observation_store() -> io::Result<LocalObservationStore> {
+    match tokio::fs::read_to_string(observation_store_path()).await {
+        Ok(s) => serde_json::from_str(&s).map_err(io::Error::other),
+        Err(e) if e.kind() == ErrorKind::NotFound => Ok(Default::default()),
+        Err(e) => Err(e),
+    }
+}
+
+pub async fn load_observation_store_from_path(
+    path: impl AsRef<Path>,
+) -> io::Result<LocalObservationStore> {
+    match tokio::fs::read_to_string(path).await {
+        Ok(s) => serde_json::from_str(&s).map_err(io::Error::other),
+        Err(e) if e.kind() == ErrorKind::NotFound => Ok(Default::default()),
+        Err(e) => Err(e),
+    }
+}
+
+async fn save_observation_store(store: &LocalObservationStore) -> io::Result<()> {
+    save_observation_store_to_path(observation_store_path(), store).await
+}
+
+async fn save_observation_store_to_path(
+    path: impl AsRef<Path>,
+    store: &LocalObservationStore,
+) -> io::Result<()> {
+    let s = serde_json::to_string(store).map_err(io::Error::other)?;
+    tokio::fs::write(path, s).await
+}
+
+pub async fn list_local_observations() -> io::Result<Vec<LocalDeviceObservation>> {
+    let store = load_observation_store().await?;
+    Ok(list_local_observations_from_store(store))
+}
+
+pub async fn list_local_observations_from_path(
+    path: impl AsRef<Path>,
+) -> io::Result<Vec<LocalDeviceObservation>> {
+    let store = load_observation_store_from_path(path).await?;
+    Ok(list_local_observations_from_store(store))
+}
+
+pub async fn prune_removed_observations_from_path(path: impl AsRef<Path>) -> io::Result<usize> {
+    let path = path.as_ref();
+    let mut store = load_observation_store_from_path(path).await?;
+    let before = store.dhcp_clients.len() + store.neighbors.len();
+    store
+        .dhcp_clients
+        .retain(|_, row| !row.last_action.eq_ignore_ascii_case("remove"));
+    store
+        .neighbors
+        .retain(|_, row| !row.last_action.eq_ignore_ascii_case("remove"));
+    let after = store.dhcp_clients.len() + store.neighbors.len();
+    let removed = before.saturating_sub(after);
+    if removed > 0 {
+        save_observation_store_to_path(path, &store).await?;
+    }
+    Ok(removed)
+}
+
+fn list_local_observations_from_store(store: LocalObservationStore) -> Vec<LocalDeviceObservation> {
+    let mut out = Vec::with_capacity(store.dhcp_clients.len() + store.neighbors.len());
+    out.extend(
+        store
+            .dhcp_clients
+            .into_values()
+            .map(|row| LocalDeviceObservation {
+                kind: "dhcp".into(),
+                action: row.last_action,
+                mac: Some(row.mac),
+                ip: row.ip,
+                hostname: row.hostname,
+                first_seen_unix: row.first_seen_unix,
+                last_seen_unix: row.last_seen_unix,
+            }),
+    );
+    out.extend(
+        store
+            .neighbors
+            .into_values()
+            .map(|row| LocalDeviceObservation {
+                kind: "neigh".into(),
+                action: row.last_action,
+                mac: row.mac,
+                ip: row.ip,
+                hostname: None,
+                first_seen_unix: row.first_seen_unix,
+                last_seen_unix: row.last_seen_unix,
+            }),
+    );
+    out.sort_by(|a, b| {
+        b.last_seen_unix
+            .cmp(&a.last_seen_unix)
+            .then(a.kind.cmp(&b.kind))
+            .then(a.mac.cmp(&b.mac))
+            .then(a.ip.cmp(&b.ip))
+    });
+    out
+}
+
+/// Observe a DHCP hotplug event and update the local MAC-to-name cache.
+pub async fn observe_dhcp_event(
+    action: &str,
+    mac: MacAddr,
+    ip: Option<IpAddr>,
+    hostname: Option<&str>,
+) -> io::Result<bool> {
+    if !matches!(action, "add" | "update" | "old" | "remove") {
+        // old not emitted by hotplug
+        return Ok(false);
+    }
+
+    let hostname = hostname
+        .map(str::trim)
+        .filter(|v| !v.is_empty() && *v != "*")
+        .map(ToOwned::to_owned);
+    let now = now_unix();
+    let mac_s = mac.to_string().to_ascii_lowercase();
+
+    let mut store = load_observation_store().await.unwrap_or_default();
+    let mut changed = false;
+    store
+        .dhcp_clients
+        .entry(mac_s.clone())
+        .and_modify(|row| {
+            if row.ip != ip
+                || row.hostname != hostname
+                || row.last_action != action
+                || row.last_seen_unix != now
+            {
+                row.ip = ip;
+                row.hostname = hostname.clone();
+                row.last_action = action.to_string();
+                row.last_seen_unix = now;
+                changed = true;
+            }
+        })
+        .or_insert_with(|| {
+            changed = true;
+            ObservedDhcpClient {
+                mac: mac_s.clone(),
+                ip,
+                hostname: hostname.clone(),
+                first_seen_unix: now,
+                last_seen_unix: now,
+                last_action: action.to_string(),
+            }
+        });
+    if changed {
+        save_observation_store(&store).await?;
+    }
+
+    if let Some(hostname) = hostname {
+        let mut cache = load_mac_name_cache().await.unwrap_or_default();
+        if cache.get(&mac_s).map(|v| v != &hostname).unwrap_or(true) {
+            cache.insert(mac_s, hostname);
+            save_mac_name_cache(&cache).await?;
+            changed = true;
+        }
+    }
+
+    Ok(changed)
+}
+
+pub async fn observe_neighbor_event(
+    action: &str,
+    mac: Option<MacAddr>,
+    ip: Option<IpAddr>,
+) -> io::Result<bool> {
+    let action = normalize_neighbor_action(action);
+    if !is_neighbor_observation_action(&action) {
+        return Ok(false);
+    }
+    let Some(key) = neighbor_observation_key(mac, ip) else {
+        return Ok(false);
+    };
+
+    let now = now_unix();
+    let mac = mac.map(|value| value.to_string().to_ascii_lowercase());
+    let mut store = load_observation_store().await.unwrap_or_default();
+    let mut changed = false;
+    let alias_keys = neighbor_observation_alias_keys(mac.as_deref(), ip, &key);
+    let mut row = store
+        .neighbors
+        .remove(&key)
+        .or_else(|| {
+            alias_keys
+                .iter()
+                .find_map(|alias| store.neighbors.remove(alias))
+        })
+        .unwrap_or_else(|| {
+            changed = true;
+            ObservedNeighbor {
+                key: key.clone(),
+                mac: mac.clone(),
+                ip,
+                first_seen_unix: now,
+                last_seen_unix: now,
+                last_action: action.clone(),
+            }
+        });
+    for alias in alias_keys {
+        if store.neighbors.remove(&alias).is_some() {
+            changed = true;
+        }
+    }
+    if row.key != key
+        || row.mac != mac
+        || row.ip != ip
+        || row.last_action != action
+        || row.last_seen_unix != now
+    {
+        row.key = key.clone();
+        row.mac = mac.clone();
+        row.ip = ip;
+        row.last_action = action.clone();
+        row.last_seen_unix = now;
+        changed = true;
+    }
+    store.neighbors.insert(key, row);
+    if let (Some(mac), Some(ip)) = (mac.as_deref(), ip)
+        && !is_offline_neighbor_action(&action)
+    {
+        mark_replaced_neighbor_ips_removed(&mut store, mac, ip, now, &mut changed);
+    }
+    if changed {
+        save_observation_store(&store).await?;
+    }
+    Ok(changed)
+}
+
+fn normalize_neighbor_action(action: &str) -> String {
+    match action.trim().to_ascii_lowercase().as_str() {
+        "del" => "remove".into(),
+        "old" => "update".into(),
+        other => other.to_string(),
+    }
+}
+
+fn is_neighbor_observation_action(action: &str) -> bool {
+    matches!(action, "add" | "update" | "remove")
+}
+
+fn is_offline_neighbor_action(action: &str) -> bool {
+    action == "remove"
+}
+
+fn neighbor_observation_key(mac: Option<MacAddr>, ip: Option<IpAddr>) -> Option<String> {
+    match (mac, ip) {
+        (Some(mac), Some(ip)) => Some(format!(
+            "mac:{}:ip:{ip}",
+            mac.to_string().to_ascii_lowercase()
+        )),
+        (Some(mac), None) => Some(format!("mac:{}", mac.to_string().to_ascii_lowercase())),
+        (None, Some(ip)) => Some(format!("ip:{ip}")),
+        (None, None) => None,
+    }
+}
+
+fn neighbor_observation_alias_keys(
+    mac: Option<&str>,
+    ip: Option<IpAddr>,
+    primary_key: &str,
+) -> Vec<String> {
+    let mut keys = Vec::with_capacity(2);
+    if let Some(mac) = mac {
+        keys.push(format!("mac:{mac}"));
+    }
+    if let Some(ip) = ip {
+        keys.push(format!("ip:{ip}"));
+    }
+    keys.retain(|key| key != primary_key);
+    keys
+}
+
+fn mark_replaced_neighbor_ips_removed(
+    store: &mut LocalObservationStore,
+    mac: &str,
+    current_ip: IpAddr,
+    now: u64,
+    changed: &mut bool,
+) {
+    for row in store.neighbors.values_mut() {
+        let Some(row_ip) = row.ip else {
+            continue;
+        };
+        if row.mac.as_deref() == Some(mac)
+            && row_ip != current_ip
+            && same_ip_family(row_ip, current_ip)
+            && !is_offline_neighbor_action(&row.last_action)
+        {
+            row.last_action = "remove".into();
+            row.last_seen_unix = now;
+            *changed = true;
+        }
+    }
+}
+
+fn same_ip_family(a: IpAddr, b: IpAddr) -> bool {
+    matches!(
+        (a, b),
+        (IpAddr::V4(_), IpAddr::V4(_)) | (IpAddr::V6(_), IpAddr::V6(_))
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use serial_test::serial;
+
+    struct EnvGuard {
+        keys: Vec<&'static str>,
+    }
+
+    impl EnvGuard {
+        fn set(key: &'static str, value: &std::path::Path) -> Self {
+            let guard = Self { keys: vec![key] };
+            // SAFETY: these tests are serialized and do not spawn work that reads these
+            // environment variables outside the test body.
+            unsafe {
+                std::env::set_var(key, value);
+            }
+            guard
+        }
+    }
+
+    impl Drop for EnvGuard {
+        fn drop(&mut self) {
+            for key in &self.keys {
+                // SAFETY: these tests are serialized and do not spawn work that reads these
+                // environment variables outside the test body.
+                unsafe {
+                    std::env::remove_var(key);
+                }
+            }
+        }
+    }
+
+    fn temp_file(name: &str) -> PathBuf {
+        let nonce = SystemTime::now()
+            .duration_since(UNIX_EPOCH)
+            .map(|duration| duration.as_nanos())
+            .unwrap_or(0);
+        std::env::temp_dir().join(format!("wakey-linux-{name}-{}-{nonce}", std::process::id()))
+    }
+
+    #[tokio::test]
+    #[serial]
+    async fn observation_and_name_cache_paths_can_be_overridden() {
+        let observation_path = temp_file("observations");
+        let cache_path = temp_file("names");
+        let _observation_guard = EnvGuard::set(OBSERVATION_STORE_ENV, &observation_path);
+        let _cache_guard = EnvGuard::set(MAC_NAME_CACHE_ENV, &cache_path);
+
+        let changed = observe_dhcp_event(
+            "add",
+            "aa:bb:cc:dd:ee:ff".parse().expect("mac should parse"),
+            Some("192.168.1.2".parse().expect("ip should parse")),
+            Some("lda"),
+        )
+        .await
+        .expect("observation should write");
+        assert!(changed);
+
+        let store = load_observation_store()
+            .await
+            .expect("observation store should read");
+        assert!(store.dhcp_clients.contains_key("aa:bb:cc:dd:ee:ff"));
+
+        let cache = load_mac_name_cache().await.expect("name cache should read");
+        assert_eq!(cache.get("aa:bb:cc:dd:ee:ff"), Some(&"lda".to_string()));
+
+        let _ = tokio::fs::remove_file(observation_path).await;
+        let _ = tokio::fs::remove_file(cache_path).await;
+    }
+
+    #[tokio::test]
+    #[serial]
+    async fn neighbor_observations_are_keyed_by_mac_ip_pair() {
+        let observation_path = temp_file("neighbor-observations");
+        let _observation_guard = EnvGuard::set(OBSERVATION_STORE_ENV, &observation_path);
+        let mac = "aa:bb:cc:dd:ee:ff".parse().expect("mac should parse");
+
+        observe_neighbor_event(
+            "add",
+            Some(mac),
+            Some("192.168.1.2".parse().expect("ip should parse")),
+        )
+        .await
+        .expect("first observation should write");
+        observe_neighbor_event(
+            "update",
+            Some(mac),
+            Some("192.168.1.3".parse().expect("ip should parse")),
+        )
+        .await
+        .expect("second observation should write");
+
+        let store = load_observation_store()
+            .await
+            .expect("observation store should read");
+        assert!(
+            store
+                .neighbors
+                .contains_key("mac:aa:bb:cc:dd:ee:ff:ip:192.168.1.2")
+        );
+        assert!(
+            store
+                .neighbors
+                .contains_key("mac:aa:bb:cc:dd:ee:ff:ip:192.168.1.3")
+        );
+        assert_eq!(
+            store.neighbors["mac:aa:bb:cc:dd:ee:ff:ip:192.168.1.2"].last_action,
+            "remove"
+        );
+
+        let _ = tokio::fs::remove_file(observation_path).await;
+    }
+
+    #[tokio::test]
+    #[serial]
+    async fn neighbor_observation_migrates_coarse_mac_key_to_mac_ip_pair() {
+        let observation_path = temp_file("neighbor-observations-migrate");
+        let _observation_guard = EnvGuard::set(OBSERVATION_STORE_ENV, &observation_path);
+        let mut neighbors = std::collections::BTreeMap::new();
+        neighbors.insert(
+            "mac:aa:bb:cc:dd:ee:ff".to_string(),
+            ObservedNeighbor {
+                key: "mac:aa:bb:cc:dd:ee:ff".to_string(),
+                mac: Some("aa:bb:cc:dd:ee:ff".to_string()),
+                ip: None,
+                first_seen_unix: 1,
+                last_seen_unix: 1,
+                last_action: "add".to_string(),
+            },
+        );
+        let fixture = LocalObservationStore {
+            dhcp_clients: Default::default(),
+            neighbors,
+        };
+        tokio::fs::write(
+            &observation_path,
+            serde_json::to_string(&fixture).expect("fixture should serialize"),
+        )
+        .await
+        .expect("fixture should write");
+
+        observe_neighbor_event(
+            "update",
+            Some("aa:bb:cc:dd:ee:ff".parse().expect("mac should parse")),
+            Some("192.168.1.2".parse().expect("ip should parse")),
+        )
+        .await
+        .expect("observation should write");
+
+        let store = load_observation_store()
+            .await
+            .expect("observation store should read");
+        assert!(!store.neighbors.contains_key("mac:aa:bb:cc:dd:ee:ff"));
+        let row = store
+            .neighbors
+            .get("mac:aa:bb:cc:dd:ee:ff:ip:192.168.1.2")
+            .expect("coarse key should migrate to pair key");
+        assert_eq!(row.first_seen_unix, 1);
+        assert_eq!(row.mac.as_deref(), Some("aa:bb:cc:dd:ee:ff"));
+        assert_eq!(
+            row.ip
+                .expect("ip should be carried into migrated row")
+                .to_string(),
+            "192.168.1.2"
+        );
+        assert_eq!(row.last_action, "update");
+
+        let _ = tokio::fs::remove_file(observation_path).await;
+    }
+}