ceph_entity_addr_encoding_len
int ceph_entity_addr_encoding_len(const struct ceph_entity_addr *addr);
ctrl_len = 1 + ceph_entity_addr_encoding_len(&con->peer_addr);
ctrl_len = 1 + 4 + ceph_entity_addr_encoding_len(my_addr) +
ceph_entity_addr_encoding_len(&con->peer_addr) + 6 * 8;
ctrl_len = 1 + 4 + ceph_entity_addr_encoding_len(my_addr) + 5 * 8;