fsm_close
void fsm_close(fsm *, const char *);
fsm_close(f, NULL);
fsm_close(f, NULL);
fsm_close(f, "Authentication is required");
fsm_close(&_this->lcp.fsm, reason);
fsm_close(&_this->lcp.fsm, NULL);
fsm_close(&ccp_fsm[unit], reason);
void fsm_close(fsm *, char *);
fsm_close(&ipcp_fsm[unit], reason);
fsm_close(&lcp_fsm[unit], reason);