feat(mesh): app direct ports reachable over the mesh — IPv4 listeners mirrored onto [::]

The companion reaches the node at its fips0 ULA, and the web UI builds app
links as http://[<ULA>]:<direct port> — but rootless-podman published ports
bind 0.0.0.0 only, so every app URL was refused over the mesh (:8334 first).
A reconcile loop in the backend mirrors public IPv4 listeners: any port
>=1024 on 0.0.0.0 without an IPv6 any-listener gets a v6-ONLY [::] forwarder
to 127.0.0.1, following /proc/net/tcp* so install/remove and hardcoded
companion ports are covered without touching a single container. Purely
additive: IPv4/LAN/Tor access paths are untouched, v6only listeners cannot
collide with or intercept v4 traffic, and foreign IPv6 listeners win.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

core/Cargo.lock

@@ -145,6 +145,7 @@ dependencies = [
  "serde_yaml",
  "serial2-tokio",
  "sha2 0.10.9",
+ "socket2 0.5.10",
  "tar",
  "tempfile",
  "thiserror 1.0.69",

core/archipelago/Cargo.toml

@@ -22,6 +22,9 @@ iroh-swarm = ["dep:iroh", "dep:iroh-blobs"]
 [dependencies]
 # Core dependencies
 tokio = { version = "1", features = ["full"] }
+# Mesh port mirror: needs IPV6_V6ONLY on [::] listeners so they coexist with
+# the containers' own 0.0.0.0 binds (std/tokio don't expose the sockopt).
+socket2 = "0.5"
 libc = "0.2"   # process-group signalling for the supervised reticulum daemon
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"

core/archipelago/src/main.rs

@@ -34,6 +34,7 @@ mod bitcoin_rpc;
 mod bitcoin_status;
 mod blobs;
 mod bootstrap;
+mod mesh_ports;
 mod ceremony;
 mod config;
 mod constants;
@@ -395,6 +396,10 @@ async fn main() -> Result<()> {
     // iframe on kiosk nodes (docs/tv-input-iframe-apps.md).
     tokio::spawn(bootstrap::ensure_gamepad_keys());
 
+    // Mesh access: mirror IPv4-published app ports onto [::] so direct-port
+    // app URLs (http://[<fips0 ULA>]:<port>) work from the companion.
+    tokio::spawn(mesh_ports::run_mesh_port_mirror());
+
     // Pine voice: re-point IP-pinned Wyoming satellite entries (speakers) when
     // DHCP renumbering strands them — HA never re-resolves on its own.
     tokio::spawn(api::rpc::wyoming_satellite_keeper());

core/archipelago/src/mesh_ports.rs

@@ -0,0 +1,145 @@
+//! Mirror IPv4-published app ports onto IPv6 for mesh access.
+//!
+//! The companion (and anything else on the FIPS mesh) reaches this node at
+//! its fips0 ULA. The web UI builds app links from the current host + each
+//! app's DIRECT port (Direct Port Rule) — but rootless-podman published
+//! ports bind 0.0.0.0 only, so `http://[<ULA>]:8334` was refused for every
+//! catalog app even after nginx :80 learned IPv6 (2026-07-23, third
+//! "the node wasn't listening on v6" bug of the night).
+//!
+//! Instead of touching the container layer (port-publish changes would
+//! recreate every container), a reconcile loop mirrors the host's public
+//! IPv4 listeners: any port ≥1024 listening on 0.0.0.0 without an IPv6
+//! any-address listener gets a v6-only `[::]:<port>` forwarder to
+//! `127.0.0.1:<port>`. Ports appear/disappear with app install/remove, so
+//! the mirror follows `/proc/net/tcp*` rather than the catalog — companion
+//! containers with hardcoded ports (bitcoin-ui :8334) are covered the same
+//! as manifest-declared ones. Nothing is exposed that IPv4 didn't already
+//! expose to the LAN; the ULA is the established remote-access surface.
+
+use std::collections::{HashMap, HashSet};
+use std::net::{Ipv6Addr, SocketAddrV6};
+use std::time::Duration;
+
+use anyhow::{Context, Result};
+use tokio::task::JoinHandle;
+use tracing::{debug, info, warn};
+
+const RECONCILE_INTERVAL: Duration = Duration::from_secs(15);
+/// Never mirror system ports; nginx (80/443) handles its own v6 listeners.
+const MIN_PORT: u16 = 1024;
+
+/// Entry point — spawned from main; runs for the process lifetime.
+pub async fn run_mesh_port_mirror() {
+    let mut active: HashMap<u16, JoinHandle<()>> = HashMap::new();
+    loop {
+        match reconcile(&mut active).await {
+            Ok(()) => {}
+            Err(e) => debug!("mesh-ports: reconcile skipped: {e:#}"),
+        }
+        tokio::time::sleep(RECONCILE_INTERVAL).await;
+    }
+}
+
+async fn reconcile(active: &mut HashMap<u16, JoinHandle<()>>) -> Result<()> {
+    let v4 = listening_ports("/proc/net/tcp", 8).await?;
+    let v6 = listening_ports("/proc/net/tcp6", 32).await?;
+
+    // Drop mirrors whose backing IPv4 listener vanished (app removed/stopped).
+    active.retain(|port, handle| {
+        if v4.contains(port) && !handle.is_finished() {
+            true
+        } else {
+            handle.abort();
+            info!("mesh-ports: released [::]:{port} (backing 0.0.0.0 listener gone)");
+            false
+        }
+    });
+
+    for port in v4 {
+        if port < MIN_PORT || active.contains_key(&port) {
+            continue;
+        }
+        // A foreign IPv6 any-listener already serves this port (our own
+        // mirrors are excluded above via `active`).
+        if v6.contains(&port) {
+            continue;
+        }
+        match spawn_forwarder(port) {
+            Ok(handle) => {
+                info!("mesh-ports: mirroring [::]:{port} -> 127.0.0.1:{port}");
+                active.insert(port, handle);
+            }
+            Err(e) => debug!("mesh-ports: cannot mirror port {port}: {e:#}"),
+        }
+    }
+    Ok(())
+}
+
+/// Ports in LISTEN state bound to the any-address, parsed from /proc/net/tcp
+/// (`addr_hex_len` 8) or /proc/net/tcp6 (32).
+async fn listening_ports(path: &str, addr_hex_len: usize) -> Result<HashSet<u16>> {
+    let raw = tokio::fs::read_to_string(path)
+        .await
+        .with_context(|| format!("read {path}"))?;
+    let any_addr = "0".repeat(addr_hex_len);
+    let mut ports = HashSet::new();
+    for line in raw.lines().skip(1) {
+        let mut cols = line.split_whitespace();
+        let (Some(_sl), Some(local), Some(_rem), Some(state)) =
+            (cols.next(), cols.next(), cols.next(), cols.next())
+        else {
+            continue;
+        };
+        if state != "0A" {
+            continue; // not LISTEN
+        }
+        let Some((addr, port_hex)) = local.split_once(':') else {
+            continue;
+        };
+        if addr != any_addr {
+            continue;
+        }
+        if let Ok(port) = u16::from_str_radix(port_hex, 16) {
+            ports.insert(port);
+        }
+    }
+    Ok(ports)
+}
+
+/// A v6-only listener on [::]:port forwarding each connection to 127.0.0.1:port.
+fn spawn_forwarder(port: u16) -> Result<JoinHandle<()>> {
+    use socket2::{Domain, Protocol, Socket, Type};
+    let socket = Socket::new(Domain::IPV6, Type::STREAM, Some(Protocol::TCP))
+        .context("create v6 socket")?;
+    // v6only so we coexist with the app's own 0.0.0.0:<port> bind.
+    socket.set_only_v6(true).context("set v6only")?;
+    socket.set_reuse_address(true).ok();
+    socket.set_nonblocking(true).context("set nonblocking")?;
+    let addr = SocketAddrV6::new(Ipv6Addr::UNSPECIFIED, port, 0, 0);
+    socket.bind(&addr.into()).context("bind [::]")?;
+    socket.listen(128).context("listen")?;
+    let listener = tokio::net::TcpListener::from_std(socket.into())
+        .context("register with tokio")?;
+
+    Ok(tokio::spawn(async move {
+        loop {
+            let (mut inbound, _peer) = match listener.accept().await {
+                Ok(conn) => conn,
+                Err(e) => {
+                    warn!("mesh-ports: accept failed on [::]:{port}: {e}");
+                    tokio::time::sleep(Duration::from_millis(500)).await;
+                    continue;
+                }
+            };
+            tokio::spawn(async move {
+                match tokio::net::TcpStream::connect(("127.0.0.1", port)).await {
+                    Ok(mut upstream) => {
+                        let _ = tokio::io::copy_bidirectional(&mut inbound, &mut upstream).await;
+                    }
+                    Err(e) => debug!("mesh-ports: upstream 127.0.0.1:{port} refused: {e}"),
+                }
+            });
+        }
+    }))
+}