just like how i like it

ipjs/README.md

@@ -0,0 +1,60 @@
+# lda-ipjs
+
+Typed Rust wrappers around Linux `ip -j ...` output, with optional experimental rtnetlink backends.
+
+## Purpose
+
+`lda-ipjs` exists so `wakey` can ask Linux networking questions in typed Rust instead of:
+
+- parsing plain-text shell output
+- scattering `tokio::process::Command::new("ip")` everywhere
+- mixing product logic with Linux networking trivia
+
+## Current contract
+
+Stable default behavior:
+
+- `address::get(...)` uses JSON (`ip -j address show`)
+- `link::get(...)` uses JSON (`ip -j link show`)
+- `neighbor::get(...)` uses JSON (`ip -j neigh show`)
+
+Optional experimental behavior:
+
+- feature: `experimental-nl`
+- enables rtnetlink-backed implementations
+- intended for places where one-pass kernel queries are materially better than repeated `ip -j` calls
+
+This means the public API is:
+
+- `get(...)` for the default backend
+- `get_with_backend(Backend::Json | Backend::Netlink)` when backend choice matters
+
+## Modules
+
+- `subcommands::address`
+  - typed address/interface-address data
+  - good place for subnet/broadcast derivation later
+- `subcommands::link`
+  - typed link/interface data
+  - useful for `ifindex -> ifname` mapping and interface metadata
+- `subcommands::neighbor`
+  - typed neighbor-table data
+  - currently the most useful experimental netlink surface
+
+## Backend policy
+
+JSON is the normal path.
+
+Use netlink only when:
+
+- the call is hot enough to matter
+- repeated shelling out is obviously wasteful
+- the netlink implementation is at least as coherent as the JSON one
+
+Today that mainly applies to `neighbor::nl`.
+
+## Relationship to wakey
+
+`wakey` is the product.
+
+`lda-ipjs` is a Linux networking adapter crate underneath it.

ipjs/src/subcommands/link/json.rs

@@ -0,0 +1,26 @@
+use std::{io, process::Output};
+
+use anyhow::Context;
+
+use super::LinkOutput;
+
+pub async fn get(dev: Option<&str>) -> anyhow::Result<Vec<LinkOutput>> {
+    let output = _get(dev).await.context("Can not run command")?;
+
+    if !output.status.success() {
+        anyhow::bail!(String::from_utf8_lossy(&output.stderr).into_owned());
+    }
+
+    serde_json::from_slice(&output.stdout).context("Deserialize failed")
+}
+
+pub async fn _get(dev: Option<&str>) -> io::Result<Output> {
+    let mut cmd = tokio::process::Command::new("ip");
+    cmd.args(["-j", "link", "show"]);
+
+    if let Some(d) = dev {
+        cmd.arg(d);
+    }
+
+    cmd.output().await
+}

ipjs/src/subcommands/link/mod.rs

@@ -1 +1,35 @@
-//! this is for link. You need link; at least to build an index -> name map. i Need It. sometimes.
+//! Typed wrappers for `ip -j link show`.
+
+pub mod json;
+#[cfg(all(unix, feature = "experimental-nl"))]
+pub mod nl;
+
+pub use crate::subcommands::Backend;
+use crate::utils::serialize::mac::option_mac;
+use macaddr::MacAddr;
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct LinkOutput {
+    pub ifindex: u32,
+    pub ifname: String,
+    #[serde(default)]
+    pub operstate: Option<String>,
+    #[serde(default, with = "option_mac")]
+    pub address: Option<MacAddr>,
+}
+
+pub async fn get(dev: Option<&str>) -> anyhow::Result<Vec<LinkOutput>> {
+    get_with_backend(Backend::Json, dev).await
+}
+
+pub async fn get_with_backend(
+    backend: Backend,
+    dev: Option<&str>,
+) -> anyhow::Result<Vec<LinkOutput>> {
+    match backend {
+        Backend::Json => json::get(dev).await,
+        #[cfg(all(unix, feature = "experimental-nl"))]
+        Backend::Netlink => nl::get(dev).await,
+    }
+}

ipjs/src/subcommands/link/nl.rs

@@ -0,0 +1,51 @@
+#![cfg(unix)]
+
+use futures::TryStreamExt;
+use rtnetlink::packet_route::link::LinkAttribute;
+
+use super::LinkOutput;
+
+pub async fn get(dev: Option<&str>) -> anyhow::Result<Vec<LinkOutput>> {
+    let (conn, handle, _) = rtnetlink::new_connection()?;
+    tokio::spawn(conn);
+
+    let mut req = handle.link().get();
+    if let Some(dev) = dev {
+        req = req.match_name(dev.to_owned());
+    }
+
+    let mut stream = req.execute();
+    let mut out = Vec::new();
+
+    while let Some(link) = stream.try_next().await? {
+        let mut ifname = None;
+        let mut operstate = None;
+        let mut address = None;
+
+        for attr in link.attributes {
+            match attr {
+                LinkAttribute::IfName(name) => ifname = Some(name),
+                LinkAttribute::Address(bytes) => {
+                    address = match bytes.len() {
+                        6 => bytes.first_chunk::<6>().map(|&b| macaddr::MacAddr::from(b)),
+                        8 => bytes.first_chunk::<8>().map(|&b| macaddr::MacAddr::from(b)),
+                        _ => None,
+                    }
+                }
+                LinkAttribute::OperState(state) => operstate = Some(format!("{state:?}")),
+                _ => {}
+            }
+        }
+
+        if let Some(ifname) = ifname {
+            out.push(LinkOutput {
+                ifindex: link.header.index,
+                ifname,
+                operstate,
+                address,
+            });
+        }
+    }
+
+    Ok(out)
+}

ipjs/src/subcommands/mod.rs

@@ -1,4 +1,5 @@
 pub mod address;
+pub mod link;
 pub mod neighbor;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]

ipjs/src/subcommands/neighbor/nl.rs

@@ -9,11 +9,11 @@ use futures::TryStreamExt;
 use macaddr::MacAddr;
 use rtnetlink::packet_route::{
     AddressFamily,
-    link::LinkAttribute,
     neighbour::{NeighbourAddress, NeighbourAttribute, NeighbourState},
 };
 
 use super::{NUDState, NeighborItem};
+use crate::subcommands::link;
 
 /// Fetch neighbors via rtnetlink. Empty slice = no filter (match all).
 /// Non-empty slice = match ANY in the set.
@@ -35,8 +35,12 @@ pub async fn get(
     let nud_set: HashSet<&NUDState> = nuds.iter().collect();
     let mac_set: HashSet<MacAddr> = macs.iter().copied().collect();
 
-    // Cache ifindex -> name
+    // Prefetch all links once; link lookups were the ugliest and most expensive part.
-    let mut ifname_cache: HashMap<u32, String> = HashMap::new();
+    let ifname_cache: HashMap<u32, String> = link::nl::get(None)
+        .await?
+        .into_iter()
+        .map(|link| (link.ifindex, link.ifname))
+        .collect();
     let mut result = vec![];
 
     'row: while let Some(msg) = neighbor_data.try_next().await? {
@@ -72,28 +76,7 @@ pub async fn get(
         }
 
         // Resolve ifindex -> name (cached)
-        let dev = match ifname_cache.get(&msg.header.ifindex) {
+        let dev = ifname_cache.get(&msg.header.ifindex).cloned();
-            Some(name) => Some(name.clone()),
-            None => {
-                let name = handle
-                    .link()
-                    .get()
-                    .match_index(msg.header.ifindex)
-                    .execute()
-                    .try_next()
-                    .await?
-                    .and_then(|link| {
-                        link.attributes.into_iter().find_map(|a| match a {
-                            LinkAttribute::IfName(n) => Some(n),
-                            _ => None,
-                        })
-                    });
-                if let Some(ref n) = name {
-                    ifname_cache.insert(msg.header.ifindex, n.clone());
-                }
-                name
-            }
-        };
 
         let (Some(ip), Some(dev)) = (ip, dev) else {
             continue 'row;