Allow querying specific dns server by name/ip and port
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114bda4d3f
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@ -30,6 +30,16 @@ public class Client {
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*/
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protected Random random;
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/**
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* The buffer size for dns replies.
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*/
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protected int bufferSize = 1500;
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/**
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* DNS timeout.
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*/
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protected int timeout = 5000;
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/**
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* Create a new DNS client.
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*/
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@ -41,6 +51,26 @@ public class Client {
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}
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}
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/**
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* Query a nameserver for a single entry.
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* @param name The DNS name to request.
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* @param type The DNS type to request (SRV, A, AAAA, ...).
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* @param clazz The class of the request (usually IN for Internet).
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* @param host The DNS server host.
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* @param port The DNS server port.
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* @return
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* @throws IOException On IO Errors.
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*/
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public DNSMessage query(String name, TYPE type, CLASS clazz, String host, int port)
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throws IOException
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{
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Question q = new Question();
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q.setClazz(clazz);
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q.setType(type);
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q.setName(name);
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return query(q, host, port);
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}
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/**
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* Query a nameserver for a single entry.
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* @param name The DNS name to request.
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@ -83,6 +113,17 @@ public class Client {
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* @throws IOException On IOErrors.
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*/
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public DNSMessage query(Question q, String host) throws IOException {
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return query(q, host, 53);
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}
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/**
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* Query a specific server for one entry.
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* @param q The question section of the DNS query.
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* @param host The dns server host.
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* @param port the dns port.
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* @throws IOException On IOErrors.
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*/
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public DNSMessage query(Question q, String host, int port) throws IOException {
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DNSMessage message = new DNSMessage();
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message.setQuestions(new Question[]{q});
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message.setRecursionDesired(true);
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@ -90,10 +131,10 @@ public class Client {
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byte[] buf = message.toArray();
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DatagramSocket socket = new DatagramSocket();
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DatagramPacket packet = new DatagramPacket(
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buf, buf.length, InetAddress.getByName(host), 53);
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socket.setSoTimeout(5000);
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buf, buf.length, InetAddress.getByName(host), port);
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socket.setSoTimeout(timeout);
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socket.send(packet);
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packet = new DatagramPacket(new byte[513], 513);
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packet = new DatagramPacket(new byte[bufferSize], bufferSize);
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socket.receive(packet);
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DNSMessage dnsMessage = DNSMessage.parse(packet.getData());
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if (dnsMessage.getId() != message.getId()) {
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