extern int get_certificate_valid_from_date(char *buffer, size_t buffer_size, const char *fmt);
extern int get_certificate_valid_to_date(char *buffer, size_t buffer_size, const char *fmt);
extern int host_is_ip_address(const char *host);
extern int get_certificate_valid_from_date(char *buffer, size_t buffer_size, const char *fmt);
extern int get_certificate_valid_to_date(char *buffer, size_t buffer_size, const char *fmt);
extern int host_is_ip_address(const char *host);