TY_CALLBACK
case TY_CALLBACK:
nak.hdr.id = TY_CALLBACK;
if (!REJECTED(lcp, TY_CALLBACK)) {
INC_FSM_OPT(TY_CALLBACK, 3, o);
INC_FSM_OPT(TY_CALLBACK, 3, o);
INC_FSM_OPT(TY_CALLBACK, sz + 3, o);