servnest/dns.php

<?php

function checkIpFormat($ip) {
	if (!filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE))
		userError("IP address is on the private range.");
	if (!filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_RES_RANGE))
		userError("IP address is on the reserved range.");
	if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4))
		return "A";
	if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6))
		return "AAAA";
	userError("IP address malformed.");
}

function checkAbsoluteDomainFormat($domain) {
	// If the domain must end with a dot
	if (!filter_var($domain, FILTER_VALIDATE_DOMAIN) OR !preg_match("/^([a-z0-9_-]{1,63}\.){2,127}$/", $domain))
		userError("Domain malformed.");
}

function checkAction($action) {
	if ($action === "delete")
		return "un";
	else if ($action === "add")
		return "";
	else
		userError("Wrong value for action.");
}