vmm: config: Implement Clone for NetConfig

The custom version duplicates any FDs that have been provided so that
the validation logic used on hotplug, which takes a clone of the config,
can be safely carried out.

Signed-off-by: Rob Bradford <robert.bradford@intel.com>

vmm/src/config.rs

@@ -1134,6 +1134,22 @@ impl NetConfig {
     }
 }
 
+impl Clone for NetConfig {
+    fn clone(&self) -> Self {
+        NetConfig {
+            tap: self.tap.clone(),
+            vhost_socket: self.vhost_socket.clone(),
+            id: self.id.clone(),
+            fds: self
+                .fds
+                .as_ref()
+                // SAFETY: We have been handed these FDs through the API
+                .map(|fds| fds.iter().map(|fd| unsafe { libc::dup(*fd) }).collect()),
+            ..*self
+        }
+    }
+}
+
 impl RngConfig {
     pub fn parse(rng: &str) -> Result<Self> {
         let mut parser = OptionParser::new();