TLD utilities

plugins/EmailRegistration/extlib/regDomain.inc.php

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+<?
+
+/*
+ * Calculate the effective registered domain of a fully qualified domain name.
+ *
+ * <@LICENSE>
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to you under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * </@LICENSE>
+ *
+ * Florian Sager, 25.07.2008, sager@agitos.de
+ */
+
+/*
+ * Remove subdomains from a signing domain to get the registered domain.
+ *
+ * dkim-reputation.org blocks signing domains on the level of registered domains
+ * to rate senders who use e.g. a.spamdomain.tld, b.spamdomain.tld, ... under
+ * the most common identifier - the registered domain - finally.
+ *
+ * This function returns NULL if $signingDomain is TLD itself
+ */
+
+function getRegisteredDomain($signingDomain) {
+
+	global $tldTree;
+
+	$signingDomainParts = split('\.', $signingDomain);
+
+	$result = findRegisteredDomain($signingDomainParts, $tldTree);
+
+	if ($result===NULL || $result=="") {
+		// this is an invalid domain name
+		return NULL;
+	}
+
+	// assure there is at least 1 TLD in the stripped signing domain
+	if (!strpos($result, '.')) {
+		$cnt = count($signingDomainParts);
+		if ($cnt==1 || $signingDomainParts[$cnt-2]=="") return NULL;
+		return $signingDomainParts[$cnt-2].'.'.$signingDomainParts[$cnt-1];
+	}
+	return $result;
+}
+
+// recursive helper method
+function findRegisteredDomain($remainingSigningDomainParts, &$treeNode) {
+
+	$sub = array_pop($remainingSigningDomainParts);
+
+	$result = NULL;
+	if (isset($treeNode['!'])) {
+		return '#';
+	} else if (is_array($treeNode) && array_key_exists($sub, $treeNode)) {
+		$result = findRegisteredDomain($remainingSigningDomainParts, $treeNode[$sub]);
+	} else if (is_array($treeNode) && array_key_exists('*', $treeNode)) {
+		$result = findRegisteredDomain($remainingSigningDomainParts, $treeNode['*']);
+	} else {
+		return $sub;
+	}
+
+	// this is a hack 'cause PHP interpretes '' as NULL
+	if ($result == '#') {
+		return $sub;
+	} else if (strlen($result)>0) {
+		return $result.'.'.$sub;
+	}
+	return NULL;
+}
+
+?>