From 7a6eda9ca3abcb64bd41a6b85ea56a5b3f8b0b51 Mon Sep 17 00:00:00 2001
From: tv <tv@krebsco.de>
Date: Sun, 1 Nov 2026 13:30:12 +0100
Subject: libp2p: one Book::usable for all dials

---
 src/transport/libp2p/book.rs | 40 +++++++++++++++++++++++++++++-----------
 1 file changed, 29 insertions(+), 11 deletions(-)

(limited to 'src/transport/libp2p/book.rs')

diff --git a/src/transport/libp2p/book.rs b/src/transport/libp2p/book.rs
index 087cd17..c5a73c4 100644
--- a/src/transport/libp2p/book.rs
+++ b/src/transport/libp2p/book.rs
@@ -493,18 +493,20 @@ impl Book {
     /// (`left_out`), or without a route from here (`routes`), directly or through a
     /// relay there.
     pub(super) fn left_out(&mut self, address: &Multiaddr) -> bool {
-        if left_out(&self.ignored, address) {
-            return true;
-        }
-        let at = if is_relayed(address) {
-            address
-                .iter()
-                .take_while(|protocol| !matches!(protocol, Protocol::P2pCircuit))
-                .collect::<Multiaddr>()
-        } else {
-            address.clone()
+        excluded(&self.ignored, &mut self.routes, address)
+    }
+
+    /// Where `peer` can be dialled: its known addresses, but those through this node,
+    /// and those left out (`left_out`). What every dial of ours goes to (connecting,
+    /// upgrading a relayed connection, retrying a hole punch), so none dials into a
+    /// range left out.
+    pub(super) fn usable(&mut self, peer: &PeerId, local: PeerId) -> Vec<Multiaddr> {
+        let Some(known) = self.addresses.get(peer) else {
+            return Vec::new();
         };
-        ip_of(&at).is_some_and(|ip| !self.routes.routable(ip))
+        let mut usable = dialable(known, local);
+        usable.retain(|address| !excluded(&self.ignored, &mut self.routes, address));
+        usable
     }
 
     /// Asks again which ranges have a route (`Routes::recheck`); the addresses in those
@@ -698,6 +700,22 @@ pub(super) fn book_connection(
 
 /// The addresses of `known` this node can dial: not those through itself as the relay
 /// (a relay reaches the nodes it relays for only while they are connected to it).
+/// `Book::left_out`, by the fields it needs, for where the book is borrowed in parts.
+pub(super) fn excluded(ignored: &[IpRange], routes: &mut Routes, address: &Multiaddr) -> bool {
+    if left_out(ignored, address) {
+        return true;
+    }
+    let at = if is_relayed(address) {
+        address
+            .iter()
+            .take_while(|protocol| !matches!(protocol, Protocol::P2pCircuit))
+            .collect::<Multiaddr>()
+    } else {
+        address.clone()
+    };
+    ip_of(&at).is_some_and(|ip| !routes.routable(ip))
+}
+
 pub(super) fn dialable(known: &[Multiaddr], local: PeerId) -> Vec<Multiaddr> {
     known
         .iter()
-- 
cgit v1.3.1