DNS服务检测

原帖地址    http://blog.csdn.net/stevexk/article/details/2270346

TestDns.java

import java.io.IOException;import java.io.InterruptedIOException;import java.lang.reflect.UndeclaredThrowableException;import java.net.ConnectException;import java.net.DatagramPacket;import java.net.DatagramSocket;import java.net.InetAddress;import java.net.NoRouteToHostException;import java.net.UnknownHostException;public class TestDns {    public static void main(String[] args){        // get the parameters        //        int retry = 2;        int port = 53;        int timeout = 3000;        // Host to lookup?        //        String lookup = "www.google.com";        if (lookup == null || lookup.length() == 0) {            // Get hostname of local machine for future DNS lookups            //            try {                lookup = InetAddress.getLocalHost().getHostName();            } catch (UnknownHostException ukE) {                // Recast the exception as a Service Monitor Exception                //                ukE.fillInStackTrace();                throw new UndeclaredThrowableException(ukE);            }        }        // get the address and DNS address request        //        InetAddress ipv4Addr = null;        try {            ipv4Addr = InetAddress.getByName("165.87.13.129");        } catch (UnknownHostException e1) {            // TODO Auto-generated catch block            e1.printStackTrace();        }        DNSAddressRequest request = new DNSAddressRequest(lookup);        int serviceStatus = -1;        DatagramSocket socket = null;        long responseTime = -1;        try {            socket = new DatagramSocket();            socket.setSoTimeout(timeout); // will force the                                            // InterruptedIOException            for (int attempts = 0; attempts <= retry && serviceStatus != 1; attempts++) {                try {                    // Send DNS request                    //                    byte[] data = request.buildRequest();                    DatagramPacket outgoing = new DatagramPacket(data, data.length, ipv4Addr, port);                    long sentTime = System.currentTimeMillis();                    socket.send(outgoing);                    // Get DNS Response                    //                    byte[] buffer = new byte[512];                    DatagramPacket incoming = new DatagramPacket(buffer, buffer.length);                    socket.receive(incoming);                    responseTime = System.currentTimeMillis() - sentTime;                    // Validate DNS Response                    // IOException thrown if packet does not decode as expected.                    request.verifyResponse(incoming.getData(), incoming.getLength());                    System.out.println(incoming.getAddress());                                        System.out.println("poll: valid DNS request received, responseTime= " + responseTime + "ms");                    serviceStatus = 1;                } catch (InterruptedIOException ex) {                    // Ignore, no response received.                }            }        } catch (NoRouteToHostException e) {            e.fillInStackTrace();            System.out.println("No route to host exception for address: " + ipv4Addr);        } catch (ConnectException e) {            // Connection refused. Continue to retry.            //            e.fillInStackTrace();            System.out.println("Connection exception for address: " + ipv4Addr);        } catch (IOException ex) {            ex.fillInStackTrace();            System.out.println("IOException while polling address: " + ipv4Addr);        } finally {            if (socket != null)                socket.close();        }        // Store response time if available        //        if (serviceStatus == 1) {            System.out.println("response time="+responseTime);        }    }}

DNSAddressRequest.java

//// This file is part of the OpenNMS(R) Application.//// OpenNMS(R) is Copyright (C) 2002-2003 The OpenNMS Group, Inc.  All rights reserved.// OpenNMS(R) is a derivative work, containing both original code, included code and modified// code that was published under the GNU General Public License. Copyrights for modified // and included code are below.//// OpenNMS(R) is a registered trademark of The OpenNMS Group, Inc.//// Copyright (C) 1999-2001 Oculan Corp.  All rights reserved.//// This program is free software; you can redistribute it and/or modify// it under the terms of the GNU General Public License as published by// the Free Software Foundation; either version 2 of the License, or// (at your option) any later version.//// This program is distributed in the hope that it will be useful,// but WITHOUT ANY WARRANTY; without even the implied warranty of// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the// GNU General Public License for more details.//// You should have received a copy of the GNU General Public License// along with this program; if not, write to the Free Software// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.//// For more information contact://      OpenNMS Licensing       <[e-mail]>//      http://www.opennms.org///      http://www.opennms.com///import java.io.ByteArrayInputStream;import java.io.EOFException;import java.io.IOException;/** * <P> * DNSInputStrean extends a ByteArrayInputStream and has methods to decode the * data of a DNS response to an address resquest. * </P> *  * @author <A HREF="mailto:[e-mail]">Sowmya </A> * @author <A HREF="http://www.opennms.org">OpenNMS </A> *  */public class DNSInputStream extends ByteArrayInputStream {    /**     * <P>     * Constructs a new input stream for decoding DNS records.     * </P>     *      * @param data     *            The array of data to pass to the base class.     */    public DNSInputStream(byte[] data) {        super(data);    }    /**     * <P>     * Constructs a DNSInputStream object from the byte array.     * </P>     *      * @param data     *            byte array containing the response data     * @param off     *            offset of the data in the byte array     * @param len     *            length of the byte array     */    public DNSInputStream(byte[] data, int off, int len) {        super(data, off, len);    }    /**     * <P>     * Read a byte off the input stream.     * </P>     *      * @return The integer read.     *      * @exception java.io.IOException     *                Thrown if the end-of-file is encountered trying to read     *                the next byte.     */    public int readByte() throws IOException {        int rc = read();        if (rc == -1)            throw new EOFException("end of buffer on read");        return rc;    }    /**     * <P>     * Read a 'short' off the input stream.     * </P>     *      * @return The short from the input stream.     *      * @exception java.io.IOException     *                Thrown if the end-of-file is encountered trying to read     *                the next short.     */    public int readShort() throws IOException {        return (readByte() << 8 | readByte());    }    /**     * <P>     * Read an 'int' off the input stream.     * </P>     *      * @return The int from the input stream.     *      * @exception java.io.IOException     *                Thrown if there is an error while read.     */    public long readInt() throws IOException {        long rc = 0;        for (int i = 0; i < 4; i++)            rc = (rc << 8) | readByte();        return rc;    }    /**     * <P>     * Read a 'string' off the input stream.     * </P>     *      * @return the string from the input stream     *      * @exception java.io.IOException     *                Thrown if there is an error while read     */    public String readString() throws IOException {        int len = readByte();        if (len == 0) {            return "";        }        byte[] buffer = new byte[len];        int rc = read(buffer);        if (rc == -1 || rc != len)            throw new EOFException("end of file while reading array");        return new String(buffer);    }    /**     * <P>     * The readDomainName method is used to read an entire domain name from the     * stream. The string returned will be the concatentation of several     * substrings, each substring in the record is separated by a '.'(dot). For     * more information see the RFC for the distributed name service.     * </P>     *      * @return The domain name string.     *      * @exception java.io.IOException     *                Thrown if an error occurs decoding the string from the     *                stream.     */    public String readDomainName() throws IOException {        //        // Check to make sure that we are not going        // to index the array and generate an bounds        // exception.        //        if (pos >= count)            throw new EOFException("EOF reading domain name");        //        // check the length byte. If the upper two bits are        // not set then it is a normal string and can be        // decoded using the readString() method.        //        if ((buf[pos] & 0xc0) == 0) {            String label = readString();            if (label.length() > 0) {                //                // get the next component(s) of the                // domain name. This is a recursive call.                // If the length is not equal to null then                // append the tail and return the new domain                // name.                //                String tail = readDomainName();                if (tail.length() > 0)                    label = label + '.' + tail;            }            return label;        }        //        // If this point in the code is reached then        // compression is being used!        //        //        // If the upper two bits were set then this is a special        // encoding that points us to somewhere else in the record!        // We have to read that part of the record and to get the        // next element in the stream.        //         // Throw an I/O exception if the compression offset is        // malformed.        //        if ((buf[pos] & 0xc0) != 0xc0)            throw new IOException("Invalid domain name compression offset");        //        // read the short that is the pointer to the other        // part of the stream. Note buf is a protected buffer.        //        int offset = readShort() & 0x3fff;        DNSInputStream dnsIn = new DNSInputStream(buf, offset, buf.length - offset);        return dnsIn.readDomainName();    }    /**     * <P>     * Reads the resource record from the input stream.     * </P>     *      * @return The DNSAddressRR that is in response to the address request.     *      * @exception java.io.IOException     *                Thrown if data does not decode to a DNSAddressRRl.     */    public DNSAddressRR readRR() throws IOException {        String rrName = readDomainName();        int rrType = readShort();        int rrClass = readShort();        long rrTTL = readInt();        int rrDataLen = readShort();        //        // Convert the length of data in this byte array input stream        // into a "substream" of data. The only way this could get        // complicated is if there are multiple threads using this        // stream. If that is the case then synchronization code        // should be used to wrap the next two lines -- Weave        //        DNSInputStream rrDNSIn = new DNSInputStream(buf, pos, rrDataLen);        pos += rrDataLen;        try {            //            // Create the route record and return it to            // the caller.            //            DNSAddressRR rr = new DNSAddressRR(rrName, rrType, rrClass, rrTTL, rrDNSIn);            return rr;        } catch (Exception ex) {            throw new IOException("Unknown DNSAddressRR (type " + " (" + rrType + "))" + " Originating Exception: " + ex.getMessage());        }    }}

DNSAddressRR.java

//// This file is part of the OpenNMS(R) Application.//// OpenNMS(R) is Copyright (C) 2002-2003 The OpenNMS Group, Inc.  All rights reserved.// OpenNMS(R) is a derivative work, containing both original code, included code and modified// code that was published under the GNU General Public License. Copyrights for modified // and included code are below.//// OpenNMS(R) is a registered trademark of The OpenNMS Group, Inc.//// Copyright (C) 1999-2001 Oculan Corp.  All rights reserved.//// This program is free software; you can redistribute it and/or modify// it under the terms of the GNU General Public License as published by// the Free Software Foundation; either version 2 of the License, or// (at your option) any later version.//// This program is distributed in the hope that it will be useful,// but WITHOUT ANY WARRANTY; without even the implied warranty of// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the// GNU General Public License for more details.//// You should have received a copy of the GNU General Public License// along with this program; if not, write to the Free Software// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.//// For more information contact://      OpenNMS Licensing       <[e-mail]>//      http://www.opennms.org///      http://www.opennms.com///import java.io.IOException;import java.net.InetAddress;import java.net.UnknownHostException;/** * <P> * Holds a DNS resource record which is a DNS response that gives the IP address * of a particular hostname. A resource record typically has: * </P> *  * <TABLE BORDER=0> * <TH> * <TD>Element</TD> * <TD>Description</TD> * </TH> * <TR> * <TD>Name</TD> * <TD>Domain name that the resource record describes.</TD> * </TR> * <TR> * <TD>Type</TD> * <TD>Type of RR.</TD> * </TR> * <TR> * <TD>Class</TD> * <TD>RR Class.</TD> * </TR> * <TR> * <TD>TTL</TD> * <TD>Time-To-Live for the RR.</TD> * </TR> * <TR> * <TD>RDLEN</TD> * <TD>Length of the following data.</TD> * </TR> * <TR> * <TD>Data</TD> * <TD>Actual data of this RR.</TD> * </TR> * </TABLE> *  * @author <A HREF="mailto:[e-mail]">Sowmya </A> * @author <A HREF="http://www.opennms.org/">OpenNMS </A> *  */public final class DNSAddressRR {    /**     * <P>     * Name of this RR.     * </P>     */    private String m_name;    /**     * <P>     * Type of this RR.     * </P>     */    private int m_type;    /**     * <P>     * Class of this RR.     * </P>     */    private int m_class;    /**     * <P>     * Time to live for this RR.     * </P>     */    private long m_TTL;    /**     * <P>     * Time at which this RR was created.     * </P>     */    private long m_created;    /**     * <P>     * The IP Address for the Route Record.     * </P>     */    private int[] ipAddress;    /**     * <P>     * Returns the address in the dotted decimal format.     * </P>     *      * @return The address in the dotted decimal format.     */    private String AddressToByteString() {        return ipAddress[0] + "." + ipAddress[1] + "." + ipAddress[2] + "." + ipAddress[3];    }    /**     * <P>     * Constructs an new DNS Address Resource Record with the specified     * information.     * </P>     *      * @param name     *            name of the RR     * @param type     *            type of the RR     * @param clas     *            class of the RR     * @param ttl     *            time for which this RR is valid     * @param dnsIn     *            inputstream for this RR     *      * @exception java.io.IOException     *                Thrown if an error occurs decoding data from the passed     *                DNSInputStream.     */    public DNSAddressRR(String name, int type, int clas, long ttl, DNSInputStream dnsIn) throws IOException {        m_name = name;        m_type = type;        m_class = clas;        m_TTL = ttl;        m_created = System.currentTimeMillis();        // decode        ipAddress = new int[4];        for (int i = 0; i < 4; ++i) {            ipAddress[i] = dnsIn.readByte();        }    }    /**     * <P>     * Returns the address from the address record as a byte array.     * </P>     *      * @return The address as a byte array.     */    public byte[] getAddress() {        byte[] ip = new byte[4];        for (int j = 0; j < 4; j++)            ip[j] = (byte) (ipAddress[j]);        return ip;    }    /**     * <P>     * the InetAddress of the address contained for the record.     * </P>     *      * @return The InetAddress of the address     *      * @exception java.net.UnknownHostException     *                Thrown if the InetAddress object cannot be constructed.     */    public InetAddress getInetAddress() throws UnknownHostException {        return InetAddress.getByName(AddressToByteString());    }    /**     * <P>     * Converts the object to a textual string that describes the resource     * record.     * </P>     *      * @return The string describing the object.     */    public String toString() {        return getRRName() + "Internet Address = " + AddressToByteString();    }    /**     * <P>     * Returns the name of this RR.     * </P>     *      * @return The name of this RR.     */    public String getRRName() {        return m_name;    }    /**     * <P>     * Returns the type of this RR.     * </P>     *      * @return The type of this RR.     */    public int getRRType() {        return m_type;    }    /**     * <P>     * Returns the class of this RR.     * </P>     *      * @return The class of this RR.     */    public int getRRClass() {        return m_class;    }    /**     * <P>     * Returns the TTL of this RR.     * </P>     *      * @return the TTL of this RR     */    public long getRRTTL() {        return m_TTL;    }    /**     * <P>     * Returns true if still valid i.e. TTL has not expired.     * </P>     *      * @return True if valid, false if not.     */    public boolean isValid() {        return m_TTL * 1000 > System.currentTimeMillis() - m_created;    }}