static HostnameValidationResult matches_common_name(const char *hostname, const X509 *server_cert) {
	int common_name_loc = -1;
	X509_NAME_ENTRY *common_name_entry = NULL;
	ASN1_STRING *common_name_asn1 = NULL;
	char *common_name_str = NULL;

	// Find the position of the CN field in the Subject field of the certificate
	common_name_loc = X509_NAME_get_index_by_NID(X509_get_subject_name((X509 *) server_cert), NID_commonName, -1);
	if (common_name_loc < 0) {
		return Error;
	}

	// Extract the CN field
	common_name_entry = X509_NAME_get_entry(X509_get_subject_name((X509 *) server_cert), common_name_loc);
	if (common_name_entry == NULL) {
		return Error;
	}

	// Convert the CN field to a C string
	common_name_asn1 = X509_NAME_ENTRY_get_data(common_name_entry);
	if (common_name_asn1 == NULL) {
		return Error;
	}			
	common_name_str = (char *) ASN1_STRING_data(common_name_asn1);

	// Make sure there isn't an embedded NUL character in the CN
	if (ASN1_STRING_length(common_name_asn1) != strlen(common_name_str)) {
		return MalformedCertificate;
	}

	// Compare expected hostname with the CN
	if (strcasecmp(hostname, common_name_str) == 0) {
		return MatchFound;
	}
	else {
		return MatchNotFound;
	}
}
static HostnameValidationResult matches_common_name(const char *hostname, const X509 *server_cert) {
	int common_name_loc = -1;
	X509_NAME_ENTRY *common_name_entry = NULL;
	ASN1_STRING *common_name_asn1 = NULL;
	char *common_name_str = NULL;

	 
	common_name_loc = X509_NAME_get_index_by_NID(X509_get_subject_name((X509 *) server_cert), NID_commonName, -1);
	if (common_name_loc < 0) {
		return Error;
	}

	 
	common_name_entry = X509_NAME_get_entry(X509_get_subject_name((X509 *) server_cert), common_name_loc);
	if (common_name_entry == NULL) {
		return Error;
	}

	 
	common_name_asn1 = X509_NAME_ENTRY_get_data(common_name_entry);
	if (common_name_asn1 == NULL) {
		return Error;
	}			
	common_name_str = (char *) ASN1_STRING_data(common_name_asn1);

	 
	if (ASN1_STRING_length(common_name_asn1) != strlen(common_name_str)) {
		return MalformedCertificate;
	}

	 
	if (strcasecmp(hostname, common_name_str) == 0) {
		return MatchFound;
	}
	else {
		return MatchNotFound;
	}
}