6 files changed, 30 insertions, 0 deletions
diff --git a/src/transport/identity.rs b/src/transport/identity.rs
index fb1600b..3ac06cb 100644
--- a/src/transport/identity.rs
+++ b/src/transport/identity.rs
@@ -632,6 +632,10 @@ impl Transport for IdentityTransport {
         self.shared.paths.discovered_seeds()
     }
 
+    fn on_seeds_found(&self, found: std::sync::Arc<tokio::sync::Notify>) {
+        self.shared.paths.on_seeds_found(found)
+    }
+
     /// A node ID resolves to itself if this node knows where it is; anything else is
     /// an address (`<scheme>:...`) or what one of the transports resolves to one (the
     /// first that does), asked WHO.
diff --git a/src/transport/libp2p/book.rs b/src/transport/libp2p/book.rs
index 8620895..3de8cef 100644
--- a/src/transport/libp2p/book.rs
+++ b/src/transport/libp2p/book.rs
@@ -111,6 +111,8 @@ pub(super) struct Book {
     /// Peers found on the LAN that speak continuum, with their address: seeds not
     /// handed out yet (`discovered_seeds`).
     pub(super) discovered: Vec<Multiaddr>,
+    /// Told when a seed is found (`Transport::on_seeds_found`).
+    pub(super) seeds_found: Option<Arc<tokio::sync::Notify>>,
 }
 
 /// What `Libp2pStats` counts since start.
@@ -253,6 +255,9 @@ impl Book {
             && self.discovered.len() < MAX_PEERS
         {
             self.discovered.push(address);
+            if let Some(found) = &self.seeds_found {
+                found.notify_one();
+            }
         }
     }
 
diff --git a/src/transport/libp2p/mod.rs b/src/transport/libp2p/mod.rs
index 0bbabc7..a159280 100644
--- a/src/transport/libp2p/mod.rs
+++ b/src/transport/libp2p/mod.rs
@@ -488,6 +488,10 @@ impl Transport for Libp2pTransport {
         }
     }
 
+    fn on_seeds_found(&self, found: Arc<tokio::sync::Notify>) {
+        lock(&self.book).seeds_found = Some(found);
+    }
+
     /// Nodes found on the LAN (mDNS) that speak continuum.
     fn discovered_seeds(&self) -> Vec<String> {
         std::mem::take(&mut lock(&self.book).discovered)
diff --git a/src/transport/mod.rs b/src/transport/mod.rs
index 5ad2427..a802269 100644
--- a/src/transport/mod.rs
+++ b/src/transport/mod.rs
@@ -818,6 +818,12 @@ pub(crate) trait Transport: Send + Sync {
         Vec::new()
     }
 
+    /// Has the transport tell `found` whenever it finds a seed by itself
+    /// (`discovered_seeds`). By default it never does.
+    fn on_seeds_found(&self, found: std::sync::Arc<tokio::sync::Notify>) {
+        let _ = found;
+    }
+
     /// Whether this node has a way to reach `peer` at all: an address of it on one of
     /// its transports. Members it can't reach aren't its neighbours (`swarm::topology`).
     /// By default yes, as for `local_addresses`.
diff --git a/src/transport/paths.rs b/src/transport/paths.rs
index ce19fd4..8149781 100644
--- a/src/transport/paths.rs
+++ b/src/transport/paths.rs
@@ -667,6 +667,13 @@ impl Paths {
             .collect()
     }
 
+    /// Each transport's (`Transport::on_seeds_found`).
+    pub(crate) fn on_seeds_found(&self, found: std::sync::Arc<tokio::sync::Notify>) {
+        for link in &self.links {
+            link.inner.on_seeds_found(found.clone());
+        }
+    }
+
     /// The address of the node a seed leads to, as paths keep it: an address of ours
     /// (`<scheme>:...`) whose transport reads it at once; with a scheme of ours, what
     /// that transport resolves the rest to (an address the transport can't read as an
diff --git a/src/transport/traffic.rs b/src/transport/traffic.rs
index e6d4a0c..6385f2e 100644
--- a/src/transport/traffic.rs
+++ b/src/transport/traffic.rs
@@ -330,6 +330,10 @@ impl Transport for CountingTransport {
         self.inner.discovered_seeds()
     }
 
+    fn on_seeds_found(&self, found: std::sync::Arc<tokio::sync::Notify>) {
+        self.inner.on_seeds_found(found)
+    }
+
     fn transports(&self) -> Vec<String> {
         self.inner.transports()
     }