- if (e) {
- /* Make 'e' most-recently-used. */
- list_remove(&e->lru_node);
- list_push_back(&ml->lrus, &e->lru_node);
- if (e->port == src_port) {
- return false;
- }
- } else {
- /* Learn a new address.
- * First drop the least recently used mac source. */