rem: if (proto == -1) {
add: if (string_to_number(s, 0, 255, &proto) == -1) {
context: parse_protocol(const char *s){	int proto = string_to_number(s, 0, 255);	if (proto == -1) {		struct protoent *pent;		if ((pent = getprotobyname(s)))			proto = pent->p_proto;		else {			unsigned int i;			for (i = 0;			     i < sizeof(chain_protos)/sizeof(struct pprot);			     i++) {				if (strcmp(s, chain_protos[i].name) == 0) {					proto = chain_protos[i].num;					break;				}			}			if (i == sizeof(chain_protos)/sizeof(struct pprot))				exit_error(PARAMETER_PROBLEM,					   "unknown protocol `%s' specified",					   s);		}	}	return (u_int16_t)proto;}