509 lines
13 KiB
Java
509 lines
13 KiB
Java
/*
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* TFTP to HTTP proxy in Java
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*
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* Copyright Ken Yap 2003
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* Released under GPL2
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*/
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import java.io.IOException;
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import java.io.InputStream;
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import java.io.FileInputStream;
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import java.io.BufferedInputStream;
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import java.io.UnsupportedEncodingException;
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import java.lang.String;
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import java.lang.StringBuffer;
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import java.lang.Thread;
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import java.lang.NumberFormatException;
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import java.net.DatagramPacket;
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import java.net.DatagramSocket;
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import java.net.InetAddress;
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import java.net.SocketException;
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import java.net.SocketTimeoutException;
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import java.nio.Buffer;
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import java.nio.ByteBuffer;
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import java.nio.BufferUnderflowException;
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import java.util.HashMap;
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import java.util.Properties;
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import org.apache.commons.httpclient.Credentials;
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import org.apache.commons.httpclient.Header;
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import org.apache.commons.httpclient.HostConfiguration;
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import org.apache.commons.httpclient.HttpClient;
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import org.apache.commons.httpclient.HttpException;
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import org.apache.commons.httpclient.HttpMethod;
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import org.apache.commons.httpclient.UsernamePasswordCredentials;
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import org.apache.commons.httpclient.methods.GetMethod;
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import org.apache.commons.logging.Log;
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import org.apache.commons.logging.LogFactory;
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/**
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* Description of the Class
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*
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*@author ken
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*@created 24 September 2003
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*/
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public class T2hproxy implements Runnable {
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/**
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* Description of the Field
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*/
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public final static String NAME = T2hproxy.class.getName();
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/**
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* Description of the Field
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*/
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public final static String VERSION = "0.1";
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/**
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* Description of the Field
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*/
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public final static int MTU = 1500;
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/**
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* Description of the Field
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*/
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public final static short TFTP_RRQ = 1;
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/**
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* Description of the Field
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*/
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public final static short TFTP_DATA = 3;
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/**
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* Description of the Field
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*/
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public final static short TFTP_ACK = 4;
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/**
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* Description of the Field
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*/
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public final static short TFTP_ERROR = 5;
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/**
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* Description of the Field
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*/
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public final static short TFTP_OACK = 6;
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/**
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* Description of the Field
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*/
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public final static short ERR_NOFILE = 1;
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/**
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* Description of the Field
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*/
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public final static short ERR_ILLOP = 4;
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/**
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* Description of the Field
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*/
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public final static int MAX_RETRIES = 5;
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/**
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* TFTP timeout in milliseconds
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*/
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public final static int TFTP_ACK_TIMEOUT = 2000;
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/**
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* Description of the Field
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*/
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public final static int DEFAULT_PROXY_PORT = 3128;
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private static Log log = LogFactory.getLog(T2hproxy.class);
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/**
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* The members below must be per thread and must not share any storage with
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* the main thread
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*/
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private DatagramSocket responsesocket;
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private DatagramPacket response;
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private InetAddress iaddr;
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private int port;
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private byte[] req;
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private String prefix;
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private String proxy = null;
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private int timeout;
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private HashMap options = new HashMap();
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private int blocksize = 512;
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private HttpClient client = new HttpClient();
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private HttpMethod method;
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private BufferedInputStream bstream = null;
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private String message;
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/**
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* Constructor for the T2hproxy object
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*
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*@param i Description of the Parameter
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*@param p Description of the Parameter
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*@param b Description of the Parameter
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*@param pf Description of the Parameter
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*@param pr Description of the Parameter
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*@param t Timeout for HTTP GET
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*/
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public T2hproxy(InetAddress i, int p, byte[] b, String pf, String pr, int t) {
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iaddr = i;
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port = p;
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// make a copy of the request buffer
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req = new byte[b.length];
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System.arraycopy(b, 0, req, 0, b.length);
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prefix = pf;
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// proxy can be null
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proxy = pr;
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timeout = t;
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}
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/**
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* Extract an asciz string from bufer
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*
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*@param buffer Description of the Parameter
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*@return The asciz value
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*/
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private String getAsciz(ByteBuffer buffer) {
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StringBuffer s = new StringBuffer();
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try {
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byte b;
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while ((b = buffer.get()) != 0) {
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s.append((char) b);
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}
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} catch (BufferUnderflowException e) {
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} finally {
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return (s.toString());
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}
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}
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/**
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* Convert a string of digits to a number, invalid => 0
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*
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*@param s Description of the Parameter
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*@return Description of the Return Value
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*/
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private int atoi(String s) {
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if (s == null) {
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return (0);
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}
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int value = 0;
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try {
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value = (new Integer(s)).intValue();
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} catch (NumberFormatException e) {
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}
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return (value);
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}
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/**
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* Wait for ack packet with timeout
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*
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*@return Return block number acked
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*/
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private int waitForAck() {
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DatagramPacket ack = new DatagramPacket(new byte[MTU], MTU);
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try {
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do {
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responsesocket.setSoTimeout(TFTP_ACK_TIMEOUT);
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responsesocket.receive(ack);
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} while (!ack.getAddress().equals(iaddr) || ack.getPort() != port);
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} catch (SocketTimeoutException e) {
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return (-1);
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} catch (Exception e) {
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log.info(e.toString(), e);
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}
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ByteBuffer buffer = ByteBuffer.wrap(ack.getData(), ack.getOffset(), ack.getLength() - ack.getOffset());
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short op;
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if ((op = buffer.getShort()) == TFTP_ACK) {
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return ((int) buffer.getShort());
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} else if (op == TFTP_ERROR) {
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return (-2);
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}
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return (-3);
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}
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/**
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* Description of the Method
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*
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*@param error Description of the Parameter
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*@param message Description of the Parameter
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*/
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private void sendError(short error, String message) {
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ByteBuffer buffer = ByteBuffer.wrap(response.getData());
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buffer.putShort(TFTP_ERROR).putShort(error).put(message.getBytes());
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response.setLength(buffer.position());
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try {
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responsesocket.send(response);
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} catch (Exception e) {
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log.info(e.toString(), e);
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}
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}
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/**
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* Description of the Method
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*
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*@return Description of the Return Value
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*/
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private boolean sendOackRecvAck() {
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ByteBuffer buffer = ByteBuffer.wrap(response.getData());
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buffer.putShort(TFTP_OACK).put("blksize".getBytes()).put((byte) 0).put(String.valueOf(blocksize).getBytes()).put((byte) 0);
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response.setLength(buffer.position());
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int retry;
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for (retry = 0; retry < MAX_RETRIES; retry++) {
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try {
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responsesocket.send(response);
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} catch (Exception e) {
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log.info(e.toString(), e);
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}
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if (waitForAck() == 0) {
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log.debug("Ack received");
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break;
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}
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}
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return (retry < MAX_RETRIES);
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}
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/**
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* Description of the Method
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*
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*@param block Description of the Parameter
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*@return Description of the Return Value
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*/
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private boolean sendDataBlock(int block) {
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int retry;
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for (retry = 0; retry < MAX_RETRIES; retry++) {
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try {
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responsesocket.send(response);
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} catch (Exception e) {
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log.info(e.toString(), e);
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}
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int ablock;
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if ((ablock = waitForAck()) == block) {
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log.debug("Ack received for " + ablock);
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break;
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} else if (ablock == -1) {
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log.info("Timeout waiting for ack");
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} else if (ablock == -2) {
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return (false);
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} else {
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log.info("Unknown opcode from ack");
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}
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}
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return (retry < MAX_RETRIES);
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}
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/**
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* Description of the Method
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*
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*@param buffer Description of the Parameter
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*@return Description of the Return Value
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*/
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private boolean handleOptions(ByteBuffer buffer) {
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for (; ; ) {
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String option = getAsciz(buffer);
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String value = getAsciz(buffer);
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if (option.equals("") || value.equals("")) {
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break;
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}
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log.info(option + " " + value);
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options.put(option, value);
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}
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blocksize = atoi((String) options.get("blksize"));
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if (blocksize < 512) {
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blocksize = 512;
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}
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if (blocksize > 1432) {
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blocksize = 1432;
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}
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return (sendOackRecvAck());
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}
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/**
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* Description of the Method
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*
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*@param url Description of the Parameter
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*/
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private void makeStream(String url) {
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// establish a connection within timeout milliseconds
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client.setConnectionTimeout(timeout);
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if (proxy != null) {
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String[] hostport = proxy.split(":");
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int port = DEFAULT_PROXY_PORT;
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if (hostport.length > 1) {
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port = atoi(hostport[1]);
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if (port == 0) {
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port = DEFAULT_PROXY_PORT;
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}
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}
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log.info("Proxy is " + hostport[0] + ":" + port);
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client.getHostConfiguration().setProxy(hostport[0], port);
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}
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// create a method object
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method = new GetMethod(url);
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method.setFollowRedirects(true);
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method.setStrictMode(false);
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try {
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int status;
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if ((status = client.executeMethod(method)) != 200) {
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log.info(message = method.getStatusText());
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return;
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}
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bstream = new BufferedInputStream(method.getResponseBodyAsStream());
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} catch (HttpException he) {
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message = he.getMessage();
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} catch (IOException ioe) {
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message = "Unable to get " + url;
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}
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}
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/**
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* Reads a block of data from URL stream
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*
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*@param stream Description of the Parameter
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*@param data Description of the Parameter
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*@param blocksize Description of the Parameter
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*@param offset Description of the Parameter
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*@return Number of bytes read
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*/
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private int readBlock(BufferedInputStream stream, byte[] data, int offset, int blocksize) {
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int status;
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int nread = 0;
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while (nread < blocksize) {
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try {
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status = stream.read(data, offset + nread, blocksize - nread);
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} catch (Exception e) {
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return (-1);
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}
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if (status < 0) {
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return (nread);
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}
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nread += status;
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}
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return (nread);
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}
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/**
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* Description of the Method
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*
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*@param filename Description of the Parameter
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*/
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private void doRrq(String filename) {
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String url = prefix + filename;
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log.info("GET " + url);
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makeStream(url);
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if (bstream == null) {
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log.info(message);
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sendError(ERR_NOFILE, message);
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return;
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}
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// read directly into send buffer to avoid buffer copying
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byte[] data;
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ByteBuffer buffer = ByteBuffer.wrap(data = response.getData());
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// dummy puts to get start position of data
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buffer.putShort(TFTP_DATA).putShort((short) 0);
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int start = buffer.position();
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int length;
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int block = 1;
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do {
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length = readBlock(bstream, data, start, blocksize);
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block &= 0xffff;
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log.debug("Block " + block + " " + length);
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// fill in the block number
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buffer.position(0);
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buffer.putShort(TFTP_DATA).putShort((short) block);
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response.setLength(start + length);
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if (!sendDataBlock(block)) {
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break;
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}
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buffer.position(start);
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block++;
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} while (length >= blocksize);
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log.info("Closing TFTP session");
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// clean up the connection resources
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method.releaseConnection();
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method.recycle();
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}
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/**
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* Main processing method for the T2hproxy object
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*/
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public void run() {
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ByteBuffer buffer = ByteBuffer.wrap(req);
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buffer.getShort();
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String filename = getAsciz(buffer);
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String mode = getAsciz(buffer);
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log.info(filename + " " + mode);
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response = new DatagramPacket(new byte[MTU], MTU, iaddr, port);
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try {
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responsesocket = new DatagramSocket();
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} catch (SocketException e) {
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log.info(e.toString(), e);
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return;
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}
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if (!handleOptions(buffer)) {
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return;
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}
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doRrq(filename);
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}
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/**
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* Description of the Method
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*
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*@param s Description of the Parameter
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*@param r Description of the Parameter
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*@param prefix Description of the Parameter
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*@param proxy Description of the Parameter
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*@param timeout Description of the Parameter
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*/
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public static void handleRequest(DatagramSocket s, DatagramPacket r, String prefix, String proxy, int timeout) {
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log.info("Connection from " + r.getAddress().getCanonicalHostName() + ":" + r.getPort());
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ByteBuffer buffer = ByteBuffer.wrap(r.getData(), r.getOffset(), r.getLength() - r.getOffset());
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if (buffer.getShort() != TFTP_RRQ) {
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DatagramPacket error = new DatagramPacket(new byte[MTU], MTU);
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ByteBuffer rbuf = ByteBuffer.wrap(error.getData());
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rbuf.putShort(TFTP_ERROR).putShort(ERR_ILLOP).put("Illegal operation".getBytes());
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error.setLength(rbuf.position());
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try {
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s.send(error);
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} catch (Exception e) {
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log.info(e.toString(), e);
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}
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return;
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}
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// fork thread
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new Thread(new T2hproxy(r.getAddress(), r.getPort(), r.getData(), prefix, proxy, timeout)).start();
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}
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/**
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* The main program for the T2hproxy class
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*
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*@param argv The command line arguments
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*@exception IOException Description of the Exception
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*/
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public static void main(String[] argv) throws IOException {
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log.info(T2hproxy.NAME + "." + T2hproxy.VERSION);
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int port = Integer.getInteger(T2hproxy.NAME + ".port", 69).intValue();
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String prefix = System.getProperty(T2hproxy.NAME + ".prefix", "http://localhost/");
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String proxy = System.getProperty(T2hproxy.NAME + ".proxy");
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int timeout = Integer.getInteger(T2hproxy.NAME + ".timeout", 5000).intValue();
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String propfile = System.getProperty(T2hproxy.NAME + ".properties");
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if (propfile != null) {
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FileInputStream pf = new FileInputStream(propfile);
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Properties p = new Properties(System.getProperties());
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p.load(pf);
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// set the system properties
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System.setProperties(p);
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}
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DatagramSocket requestsocket;
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try {
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requestsocket = new DatagramSocket(port);
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} catch (SocketException e) {
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log.info(e.toString(), e);
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return;
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}
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DatagramPacket request = new DatagramPacket(new byte[MTU], MTU);
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for (; ; ) {
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try {
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requestsocket.receive(request);
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handleRequest(requestsocket, request, prefix, proxy, timeout);
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} catch (Exception e) {
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log.info(e.toString(), e);
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}
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}
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}
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}
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