Give the connected-socket test helper one home

Carrying the in-line decrypt tests up brought a second copy of
install_connected_udp with them: netmon's tests already had one, and the
two differed only in which local address they bound. Both now call one
helper alongside make_node, on the netmon copy's wildcard bind, so the
suite that was already passing keeps the socket it was passing with.

src/node/tests/connected_udp.rs

@@ -107,36 +107,6 @@ fn far_side_frame(session: &mut NoiseSession, receiver_idx: SessionIndex) -> Vec
     build_encrypted(&header, &ciphertext)
 }
 
-/// Install a real `connect()`-ed UDP socket on a peer, the way the
-/// tick-driven activation in `dataplane::connected_udp` does.
-///
-/// The socket is opened against the loopback discard port: nothing is
-/// ever sent through it, and the tests only care whether the handle is
-/// still installed afterwards.
-#[cfg(any(target_os = "linux", target_os = "macos"))]
-fn install_connected_udp(node: &mut Node, addr: &NodeAddr, transport_id: TransportId) {
-    let local: std::net::SocketAddr = "127.0.0.1:0".parse().unwrap();
-    let peer_sa: std::net::SocketAddr = "127.0.0.1:9".parse().unwrap();
-
-    let owned = crate::transport::udp::open_connected_fd(local, peer_sa, 65_536, 65_536)
-        .expect("open a connected UDP socket");
-    let socket = std::sync::Arc::new(crate::transport::udp::ConnectedPeerSocket::from_fd(
-        owned, peer_sa, local,
-    ));
-    let (packet_tx, _packet_rx) = packet_channel(8);
-    let drain = crate::transport::udp::PeerRecvDrain::spawn(
-        socket.clone(),
-        transport_id,
-        peer_sa,
-        packet_tx,
-    )
-    .expect("spawn the peer recv drain");
-
-    node.get_peer_mut(addr)
-        .expect("peer present")
-        .set_connected_udp(socket, drain);
-}
-
 /// **The defect.**
 ///
 /// The in-line decrypt path called `set_current_addr` as a bare

src/node/tests/mod.rs

@@ -59,6 +59,39 @@ pub(super) fn make_node_with(config: Config) -> Node {
     Node::new(config).unwrap()
 }
 
+/// Install a real `connect()`-ed UDP socket on a peer, the way the tick-driven
+/// activation in `dataplane::connected_udp` does.
+///
+/// The socket is opened against the loopback discard port: nothing is ever sent
+/// through it, and the callers only care whether the handle is still installed
+/// afterwards.
+#[cfg(any(target_os = "linux", target_os = "macos"))]
+pub(super) fn install_connected_udp(
+    node: &mut Node,
+    addr: &NodeAddr,
+    transport_id: crate::transport::TransportId,
+) {
+    let local: std::net::SocketAddr = "0.0.0.0:0".parse().unwrap();
+    let peer_sa: std::net::SocketAddr = "127.0.0.1:9".parse().unwrap();
+
+    let owned = crate::transport::udp::open_connected_fd(local, peer_sa, 65_536, 65_536)
+        .expect("open a connected UDP socket");
+    let bound = crate::transport::udp::ConnectedPeerSocket::from_fd(owned, peer_sa, local);
+    let socket = std::sync::Arc::new(bound);
+    let (packet_tx, _packet_rx) = packet_channel(8);
+    let drain = crate::transport::udp::PeerRecvDrain::spawn(
+        socket.clone(),
+        transport_id,
+        peer_sa,
+        packet_tx,
+    )
+    .expect("spawn the peer recv drain");
+
+    node.get_peer_mut(addr)
+        .expect("peer present")
+        .set_connected_udp(socket, drain);
+}
+
 /// Build a test node with an explicit `max_peers` limit (replaces the removed
 /// `set_max_peers` setter; resource limits are immutable post-construction).
 pub(super) fn make_node_with_max_peers(max_peers: usize) -> Node {

src/node/tests/netmon.rs

@@ -31,35 +31,6 @@ fn identity_of(nodes: &[TestNode], j: usize) -> PeerIdentity {
     PeerIdentity::from_pubkey_full(nodes[j].node.identity().pubkey_full())
 }
 
-/// Install a real `connect()`-ed UDP socket on a peer, the way the tick-driven
-/// activation does.
-///
-/// The socket is opened against a discard port on loopback: nothing is ever
-/// sent through it, and the test only cares whether the handle survives a
-/// medium change.
-#[cfg(any(target_os = "linux", target_os = "macos"))]
-fn install_connected_udp(node: &mut Node, addr: &NodeAddr, transport_id: TransportId) {
-    let local: std::net::SocketAddr = "0.0.0.0:0".parse().unwrap();
-    let peer_sa: std::net::SocketAddr = "127.0.0.1:9".parse().unwrap();
-
-    let owned = crate::transport::udp::open_connected_fd(local, peer_sa, 65_536, 65_536)
-        .expect("open a connected UDP socket");
-    let bound = crate::transport::udp::ConnectedPeerSocket::from_fd(owned, peer_sa, local);
-    let socket = std::sync::Arc::new(bound);
-    let (packet_tx, _packet_rx) = crate::transport::packet_channel(8);
-    let drain = crate::transport::udp::PeerRecvDrain::spawn(
-        socket.clone(),
-        transport_id,
-        peer_sa,
-        packet_tx,
-    )
-    .expect("spawn the peer recv drain");
-
-    node.get_peer_mut(addr)
-        .expect("peer present")
-        .set_connected_udp(socket, drain);
-}
-
 /// **The defect this feature exists for.**
 ///
 /// Established UDP peers get a per-peer `connect()`-ed socket. `open_connected_fd`