Advertise signed peer cards on LAN

crates/geth-node/Cargo.toml

@@ -29,6 +29,7 @@ geth-ssh-identity = { path = "../geth-ssh-identity" }
 geth-store = { path = "../geth-store" }
 geth-types = { path = "../geth-types" }
 iroh.workspace = true
+swarm-discovery.workspace = true
 
 [dev-dependencies]
 tempfile.workspace = true

crates/geth-node/src/lib.rs

@@ -13,7 +13,8 @@ use geth_control::{
 use geth_crypto::AgentKey;
 use geth_db::DbResource;
 use geth_discovery::{
-    DiscoveredPeer, DiscoverySource, EndpointCandidate, PeerCard, discovery_is_untrusted_note,
+    DiscoveredPeer, DiscoverySource, EndpointCandidate, PEER_CARD_LAN_DISCOVERY_SERVICE, PeerCard,
+    discovery_is_untrusted_note, peer_card_from_txt_attributes, peer_card_txt_attributes,
 };
 use geth_document::{DocumentResource, DocumentState};
 use geth_iroh::{EndpointStatus, GethIrohConfig, GethIrohEndpoint, GethRelayMode};
@@ -193,6 +194,7 @@ pub async fn run_daemon(paths: GethPaths) -> Result<(), NodeError> {
     {
         spawn_iroh_control_accept_loop(node.clone(), endpoint);
     }
+    let _peer_card_lan_discovery = start_peer_card_lan_discovery(&node).await;
     if Path::new(&paths.socket_path()).exists() {
         std::fs::remove_file(paths.socket_path())?;
     }
@@ -259,6 +261,121 @@ async fn handle_stream(node: LocalNode, stream: UnixStream) -> Result<(), NodeEr
     Ok(())
 }
 
+async fn start_peer_card_lan_discovery(node: &LocalNode) -> Option<swarm_discovery::DropGuard> {
+    if !node.iroh_status.local_discovery || !node.iroh_status.enabled {
+        return None;
+    }
+
+    let card = match local_peer_card(node, DiscoverySource::Mdns, true).await {
+        Ok(card) => card,
+        Err(error) => {
+            tracing::warn!(%error, "signed peer-card LAN discovery disabled");
+            return None;
+        }
+    };
+    let attributes = match peer_card_txt_attributes(&card) {
+        Ok(attributes) => attributes,
+        Err(error) => {
+            tracing::warn!(%error, "could not encode peer-card LAN TXT payload");
+            return None;
+        }
+    };
+    let Some((port, addrs)) = lan_discovery_addrs(&card) else {
+        tracing::warn!(
+            "signed peer-card LAN discovery disabled because no direct Iroh address is known"
+        );
+        return None;
+    };
+
+    let paths = node.paths.clone();
+    let self_node_id = node.node_id.clone();
+    let discoverer = match swarm_discovery::Discoverer::new_interactive(
+        PEER_CARD_LAN_DISCOVERY_SERVICE.to_owned(),
+        lan_discovery_peer_id(&node.agent_id),
+    )
+    .with_addrs(port, addrs)
+    .with_txt_attributes(attributes)
+    {
+        Ok(discoverer) => discoverer,
+        Err(error) => {
+            tracing::warn!(%error, "could not build peer-card LAN discovery");
+            return None;
+        }
+    }
+    .with_callback(move |_peer_id, peer| {
+        if peer.is_expiry() {
+            return;
+        }
+        let card = match peer_card_from_txt_attributes(peer.txt_attributes()) {
+            Ok(card) => card,
+            Err(error) => {
+                tracing::debug!(%error, "ignoring invalid peer-card LAN discovery payload");
+                return;
+            }
+        };
+        if card.node_id.as_str() == self_node_id {
+            return;
+        }
+        let discovered = match DiscoveredPeer::candidate(
+            card.clone(),
+            UnixMillis(geth_store::now_ms()),
+            DiscoverySource::Mdns,
+        ) {
+            Ok(discovered) => discovered,
+            Err(error) => {
+                tracing::debug!(%error, "ignoring invalid LAN peer-card candidate");
+                return;
+            }
+        };
+        match Store::open(&paths.metadata_db()).and_then(|store| {
+            store.upsert_peer_card(&StoredPeerCard {
+                peer_id: card.node_id.to_string(),
+                card_json: serde_json::to_string(&card).map_err(geth_store::StoreError::from)?,
+                updated_at_ms: discovered.discovered_at.0,
+            })
+        }) {
+            Ok(()) => tracing::debug!(node = %card.node_id, "stored LAN peer-card candidate"),
+            Err(error) => tracing::warn!(%error, "could not store LAN peer-card candidate"),
+        }
+    });
+
+    match discoverer.spawn(&tokio::runtime::Handle::current()) {
+        Ok(guard) => {
+            tracing::info!(
+                service = PEER_CARD_LAN_DISCOVERY_SERVICE,
+                "signed peer-card LAN discovery running"
+            );
+            Some(guard)
+        }
+        Err(error) => {
+            tracing::warn!(%error, "could not start signed peer-card LAN discovery");
+            None
+        }
+    }
+}
+
+fn lan_discovery_peer_id(agent_id: &str) -> String {
+    format!("geth-{}", geth_crypto::blake3_hex(agent_id.as_bytes()))
+}
+
+fn lan_discovery_addrs(card: &PeerCard) -> Option<(u16, Vec<std::net::IpAddr>)> {
+    let mut parsed = card
+        .endpoints
+        .iter()
+        .flat_map(|endpoint| endpoint.direct_addresses.iter())
+        .filter_map(|addr| addr.parse::<std::net::SocketAddr>().ok())
+        .collect::<Vec<_>>();
+    parsed.sort_unstable();
+    parsed.dedup();
+    let port = parsed.first()?.port();
+    let addrs = parsed
+        .into_iter()
+        .filter(|addr| addr.port() == port)
+        .map(|addr| addr.ip())
+        .collect::<Vec<_>>();
+    (!addrs.is_empty()).then_some((port, addrs))
+}
+
 async fn export_peer_card(
     node: &LocalNode,
     out: Option<std::path::PathBuf>,
@@ -2143,6 +2260,32 @@ mod tests {
         .expect("write config");
     }
 
+    #[test]
+    fn lan_discovery_address_selection_uses_iroh_direct_addresses() {
+        let key = AgentKey::generate();
+        let card = PeerCard::signed(
+            "node:test".into(),
+            &key,
+            vec![EndpointCandidate {
+                endpoint_id: "endpoint:test".to_owned(),
+                relay_url: None,
+                direct_addresses: vec![
+                    "127.0.0.1:1111".to_owned(),
+                    "127.0.0.2:1111".to_owned(),
+                    "127.0.0.3:2222".to_owned(),
+                ],
+                source: DiscoverySource::Mdns,
+            }],
+            UnixMillis(1),
+        )
+        .expect("peer card");
+
+        let (port, addrs) = lan_discovery_addrs(&card).expect("lan addresses");
+
+        assert_eq!(port, 1111);
+        assert_eq!(addrs.len(), 2);
+    }
+
     #[tokio::test]
     async fn peer_ping_uses_signed_peer_card_over_iroh() {
         let left_home = tempfile::tempdir().expect("left home");