4 files changed, 43 insertions, 1 deletions

diff --git a/src/transport/identity.rs b/src/transport/identity.rs
index c597d77..303177a 100644
--- a/src/transport/identity.rs
+++ b/src/transport/identity.rs
@@ -44,7 +44,7 @@ use crate::transport::paths::{Gate, PathHandler, Paths, scheme_of};
 use crate::transport::stats::{IdentityCounts, IdentityStats, TransportStats};
 use crate::transport::traffic::Traffic;
 use crate::transport::{
-    Destination, EncodedMessage, HandlerFn, IdentityProof, MessageHandler, MessageKind,
+    Connection, Destination, EncodedMessage, HandlerFn, IdentityProof, MessageHandler, MessageKind,
     ParsedMessage, Transport,
 };
 
@@ -554,10 +554,15 @@ impl Transport for IdentityTransport {
             None => (self.shared.hinted_at(peer).into_iter().next()?, false),
         };
         let connection = self.shared.paths.connection(&address);
+        let punching = match connection {
+            Some(Connection::Relayed) => self.shared.paths.punching(&address),
+            _ => None,
+        };
         Some(Destination {
             address: self.shared.paths.location(&address),
             proven: is_proven,
             connection,
+            punching,
             paths: self.shared.paths.info(&proven),
         })
     }
diff --git a/src/transport/libp2p.rs b/src/transport/libp2p.rs
index a5541f6..610b94e 100644
--- a/src/transport/libp2p.rs
+++ b/src/transport/libp2p.rs
@@ -2334,6 +2334,17 @@ impl Transport for Libp2pTransport {
         lock(&self.book).connection(&peer)
     }
 
+    fn punching(&self, target: &str) -> Option<crate::transport::Punching> {
+        let peer = PeerId::from_str(target).ok()?;
+        let (failed, next) = *lock(&self.book).punching.get(&peer)?;
+        Some(crate::transport::Punching {
+            failed,
+            next_in_secs: next
+                .saturating_duration_since(tokio::time::Instant::now())
+                .as_secs(),
+        })
+    }
+
     fn location(&self, target: &str) -> Option<String> {
         let peer = PeerId::from_str(target).ok()?;
         let address = lock(&self.book).location(&peer)?.clone();
diff --git a/src/transport/mod.rs b/src/transport/mod.rs
index fb13ad9..40fdfc0 100644
--- a/src/transport/mod.rs
+++ b/src/transport/mod.rs
@@ -361,11 +361,24 @@ pub(crate) struct Destination {
     pub(crate) proven: bool,
     /// The transport's connection to it, if the transport has connections.
     pub(crate) connection: Option<Connection>,
+    /// While it is connected only through a relay: how hole punching went.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(crate) punching: Option<Punching>,
     /// Every address it proved itself at, best first, as the paths layer measures them
     /// (`transport::paths`).
     pub(crate) paths: Vec<stats::PathInfo>,
 }
 
+/// Hole punching to a peer connected only through a relay (libp2p), once a punch failed.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub(crate) struct Punching {
+    /// Punches that failed in a row.
+    pub(crate) failed: usize,
+    /// When it is tried again, in seconds from now (0: due).
+    pub(crate) next_in_secs: u64,
+}
+
 /// How a transport with connections (libp2p) is connected to a peer.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize)]
 #[serde(rename_all = "camelCase")]
@@ -712,6 +725,13 @@ pub(crate) trait Transport: Send + Sync {
         None
     }
 
+    /// How hole punching to `target` went, if a punch failed and it is still connected
+    /// only through a relay (libp2p). By default never.
+    fn punching(&self, target: &str) -> Option<Punching> {
+        let _ = target;
+        None
+    }
+
     /// The smoothed round-trip time of the path messages to `peer` go over, if
     /// measured (`transport::paths`). By default none.
     fn rtt(&self, peer: &str) -> Option<std::time::Duration> {
diff --git a/src/transport/paths.rs b/src/transport/paths.rs
index 13fc6db..e8858da 100644
--- a/src/transport/paths.rs
+++ b/src/transport/paths.rs
@@ -706,6 +706,12 @@ impl Paths {
         link.inner.connection(&target)
     }
 
+    /// How hole punching to `address` went (`Transport::punching`).
+    pub(crate) fn punching(&self, address: &str) -> Option<crate::transport::Punching> {
+        let (link, target) = self.split(address)?;
+        link.inner.punching(&target)
+    }
+
     /// Paths' own figures, and every transport's.
     pub(crate) fn stats(&self) -> TransportStats {
         let mut stats = TransportStats::default();