From 8fc0bb43e15e9ffa99777e478162c101557d505b Mon Sep 17 00:00:00 2001
From: tv <tv@krebsco.de>
Date: Sun, 1 Nov 2026 23:08:48 +0100
Subject: probe when reachable

---
 src/transport/libp2p/book.rs   |  3 +++
 src/transport/libp2p/driver.rs | 10 ++++++++++
 src/transport/libp2p/mod.rs    |  4 ++++
 3 files changed, 17 insertions(+)

(limited to 'src/transport/libp2p')

diff --git a/src/transport/libp2p/book.rs b/src/transport/libp2p/book.rs
index 3de8cef..0c61714 100644
--- a/src/transport/libp2p/book.rs
+++ b/src/transport/libp2p/book.rs
@@ -113,6 +113,9 @@ pub(super) struct Book {
     pub(super) discovered: Vec<Multiaddr>,
     /// Told when a seed is found (`Transport::on_seeds_found`).
     pub(super) seeds_found: Option<Arc<tokio::sync::Notify>>,
+    /// Told when others may reach this node where they couldn't before
+    /// (`Transport::on_reachable`).
+    pub(super) reachable: Option<Arc<tokio::sync::Notify>>,
 }
 
 /// What `Libp2pStats` counts since start.
diff --git a/src/transport/libp2p/driver.rs b/src/transport/libp2p/driver.rs
index 39a2a5d..6ef04e7 100644
--- a/src/transport/libp2p/driver.rs
+++ b/src/transport/libp2p/driver.rs
@@ -420,6 +420,10 @@ pub(super) async fn run(
                         book.failed_relays.remove(&relay_peer_id);
                         if !renewal {
                             book.counts.slots_granted += 1;
+                            // Peers that couldn't reach us may now, through it.
+                            if let Some(reachable) = &book.reachable {
+                                reachable.notify_one();
+                            }
                         }
                     }
                     if !renewal {
@@ -440,6 +444,12 @@ pub(super) async fn run(
                                 (Reachability::Public, Some(address.clone()))
                             }
                         };
+                        if matches!(new, NatStatus::Public(_))
+                            && !matches!(old, NatStatus::Public(_))
+                            && let Some(reachable) = &book.reachable
+                        {
+                            reachable.notify_one();
+                        }
                     }
                     nat = new;
                 }
diff --git a/src/transport/libp2p/mod.rs b/src/transport/libp2p/mod.rs
index 3ebe7f6..056b1b2 100644
--- a/src/transport/libp2p/mod.rs
+++ b/src/transport/libp2p/mod.rs
@@ -500,6 +500,10 @@ impl Transport for Libp2pTransport {
         lock(&self.book).seeds_found = Some(found);
     }
 
+    fn on_reachable(&self, reachable: Arc<tokio::sync::Notify>) {
+        lock(&self.book).reachable = Some(reachable);
+    }
+
     /// Nodes found on the LAN (mDNS) that speak continuum.
     fn discovered_seeds(&self) -> Vec<String> {
         std::mem::take(&mut lock(&self.book).discovered)
-- 
cgit v1.3.1