001 /*
002 * The MIT License
003 * Copyright (c) 2012 Microsoft Corporation
004 *
005 * Permission is hereby granted, free of charge, to any person obtaining a copy
006 * of this software and associated documentation files (the "Software"), to deal
007 * in the Software without restriction, including without limitation the rights
008 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
009 * copies of the Software, and to permit persons to whom the Software is
010 * furnished to do so, subject to the following conditions:
011 *
012 * The above copyright notice and this permission notice shall be included in
013 * all copies or substantial portions of the Software.
014 *
015 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
016 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
017 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
018 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
019 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
020 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
021 * THE SOFTWARE.
022 */
023
024 package microsoft.exchange.webservices.data.dns;
025
026 import microsoft.exchange.webservices.data.EWSConstants;
027 import microsoft.exchange.webservices.data.core.exception.dns.DnsException;
028
029 import javax.naming.NamingEnumeration;
030 import javax.naming.NamingException;
031 import javax.naming.directory.Attribute;
032 import javax.naming.directory.Attributes;
033 import javax.naming.directory.DirContext;
034 import javax.naming.directory.InitialDirContext;
035
036 import java.util.ArrayList;
037 import java.util.Hashtable;
038 import java.util.List;
039
040 /**
041 * Class that represents DNS Query client.
042 */
043 public class DnsClient {
044
045 /**
046 * Set up the environment used to construct the DirContext.
047 *
048 * @param dnsServerAddress
049 * @return
050 */
051 static Hashtable<String, String> getEnv(String dnsServerAddress) {
052 // Set up environment for creating initial context
053 Hashtable<String, String> env = new Hashtable<String, String>();
054 env.put("java.naming.factory.initial",
055 "com.sun.jndi.dns.DnsContextFactory");
056 if(dnsServerAddress != null && !dnsServerAddress.isEmpty()) {
057 env.put("java.naming.provider.url", "dns://" + dnsServerAddress);
058 }
059 return env;
060 }
061
062 /**
063 * Performs Dns query.
064 *
065 * @param <T> the generic type
066 * @param cls DnsRecord Type
067 * @param domain the domain
068 * @param dnsServerAddress IPAddress of DNS server to use (may be null)
069 * @return DnsRecord The DNS record list (never null but may be empty)
070 * @throws DnsException the dns exception
071 */
072
073 public static <T extends DnsRecord> List<T> dnsQuery(Class<T> cls, String domain, String dnsServerAddress) throws
074 DnsException {
075
076 List<T> dnsRecordList = new ArrayList<T>();
077 try {
078 // Create initial context
079 DirContext ictx = new InitialDirContext(getEnv(dnsServerAddress));
080
081 // Retrieve SRV record context attribute for the specified domain
082 Attributes contextAttributes = ictx.getAttributes(domain,
083 new String[] {EWSConstants.SRVRECORD});
084 if (contextAttributes != null) {
085 NamingEnumeration<?> attributes = contextAttributes.getAll();
086 if (attributes != null) {
087 while (attributes.hasMore()) {
088 Attribute attr = (Attribute) attributes.next();
089 NamingEnumeration<?> srvValues = attr.getAll();
090 if (srvValues != null) {
091 while (srvValues.hasMore()) {
092 T dnsRecord = cls.newInstance();
093
094 // Loads the DNS SRV record
095 dnsRecord.load((String) srvValues.next());
096 dnsRecordList.add(dnsRecord);
097 }
098 }
099 }
100 }
101 }
102 } catch (NamingException ne) {
103 throw new DnsException(ne.getMessage());
104 } catch (Exception e) {
105 throw new DnsException(e.getMessage());
106 }
107 return dnsRecordList;
108 }
109 }