Cleanup / temp buffers for various things

peer/interfaces.go

@@ -21,6 +21,8 @@ type WGDevice interface {
 
 // ControlConn sends pings to peers over the VPN control port.
 // Reading is handled separately via run, which feeds the App's pingCh.
+// buf is a caller-provided scratch buffer (at least control.Size bytes) used to
+// marshal the ping; the caller reuses one across sends.
 type ControlConn interface {
-	SendPing(dst netip.AddrPort, ping control.Ping) error
+	SendPing(dst netip.AddrPort, ping control.Ping, buf []byte) error
 }