sess_do_free
{ SESS_RUNNING, SESS_EV_CLOSED, sess_do_free }, /* XXX */
{ SESS_FAILED, SESS_EV_TIMEOUT, sess_do_free }, /* N6 */
{ SESS_FAILED, SESS_EV_FREE, sess_do_free }, /* N6 */
int sess_do_free(struct session *, struct sessev *);