从书上抄来的TFTP协议,终于调试到可以运行,已发现但未解决的问题:
1文件名编码装换不明确,不知是否需要转换,如过用ISO-8859-1转换中文文件名会出错.
2UDP用wireshark截包UDP校验和出现错误:提示:Checksum: 0x0020 [incorrect, should be 0x131f (maybe caused by "UDP checksum offload"?)]
代码作者写上自己名字了,不好意思了...
注:源程序摘自Al Williams的<>,中国水利水电出版社出版.ISBN 7-5084-1152-8
//
TFTP Class TftpSocket.java -- AD_Li
package
net.ad_li.network;
import
java.io.FileInputStream;
import
java.io.FileOutputStream;
import
java.io.IOException;
import
java.io.PrintStream;
import
java.net.DatagramPacket;
import
java.net.DatagramSocket;
import
java.net.InetAddress;
import
java.net.SocketException;
import
java.net.UnknownHostException;
/** */
/**
* A simple class for TFTP,can be use as server and client. * * Use UDP as lower level protocol. * * Super class:{@link DatagramSocket} * * @author AD
*/
public
class
TftpSocket
extends
DatagramSocket
implements
Runnable
...
{
/** *//** DEBUG FLAG set it to true to print the debug information. */ private static final boolean DEBUG = false; /** *//** Type of TFTP packet(local code none). */ protected final static int NONE = 0; /** *//** Type of TFTP packet(read request). */ protected final static int RRQ = 1; /** *//** Type of TFTP packet(write request). */ protected final static int WRQ = 2; /** *//** Type of TFTP packet(data). */ protected final static int DAT = 3; /** *//** Type of TFTP packet(acknowledgment). */ protected final static int ACK = 4; /** *//** Type of TFTP packet(error). */ protected final static int ERR = 5; /** *//** Type of TFTP packet(local code unknown). */ protected final static int UNKNOWN = 6; /** *//** Type of TFTP packet(local code timeout). */ protected static int TIMEOUT = 7; /** *//** File name in string form. */ protected String m_fNameString; /** *//** File name in byte array form. */ protected byte[] m_fNameByte; /** *//** File type in byte array form. */ protected byte[] m_fType; /** *//** Host Address use in TFTP client. */ protected InetAddress m_hostAddr; /** *//** Port use in TFTP server. */ protected int m_serverPort = 69; /** *//** Data bytes for send. */ protected byte[] m_bytesOut = new byte[516]; /** *//** Data bytes for receive. */ protected byte[] m_bytesIn = new byte[1024]; /** *//** The sequence number of the packet. */ protected int m_block; /** *//** Input stream. */ protected FileInputStream m_fileIn; /** *//** Output stream. */ protected FileOutputStream m_fileOut; /** *//** Flag of end of files */ protected boolean m_EOF = false; /** *//** Operation request(use in TFTP server as a flag of server type). */ protected int m_serverCode = 0; /** *//** Error output stream */ protected PrintStream m_errOut = System.out; /** *//** * @param fName * file name * @param fType * file type * @param host * host name can be URL or IP address
*/ public TftpSocket(String fName, String fType, String host) throws UnknownHostException, SocketException ...{ create(fName, fType, host); } /** *//** * * @param fName * file name * @param fType * file type * @param host * host name can be URL or IP address * @param serPort * local port for server * @param serAddress * local address for server */ public TftpSocket(String fName, String fType, String host, int serPort, InetAddress serAddress) throws UnknownHostException, SocketException ...{ super(serPort, serAddress); create(fName, fType, host); } /** *//** * private constructor(used by server only) */ private TftpSocket() throws SocketException ...{ } /** *//** * * @param fName * file name * @param fType * file type * @param host * host name can be URL or IP address */ private void create(String fName, String fType, String host) throws UnknownHostException, SocketException ...{ // try {// try get the file name by ISO-8859-1 and convert it into bytes // m_fNameByte = fName.getBytes("ISO-8859-1"); // } catch (Exception exce) { // exce.printStackTrace(m_errOut); // m_fNameByte = fName.getBytes(); // }//TODO:here may be need some kind of code transformation m_fNameByte = fName.getBytes(); // get the file name in string form m_fNameString = fName; // get the file type m_fType = fType.getBytes(); // set 1.5 second time-out setSoTimeout(1500); // get the host Address m_hostAddr = InetAddress.getByName(host); } /** *//** * Send a specific error packet. * * @param code * error code * @param msg * error message * @return if the error packet send successful */ protected boolean sendErrPacket(int code, String msg) ...{ // setup the error tag in packet m_bytesOut[0] = (byte) ((ERR >> 8) & 0xFF); m_bytesOut[1] = (byte) (ERR & 0xFF); // setup the error code in packet m_bytesOut[2] = (byte) ((code >> 8) & 0xFF); m_bytesOut[3] = (byte) (code & 0xFF); // setup data in packet System.arraycopy(msg.getBytes(), 0, m_bytesOut, 4, msg.length()); // setup the end in packet m_bytesOut[4 + msg.length()] = 0; // make up the whole packet DatagramPacket pack = new DatagramPacket(m_bytesOut, 5 + msg.length(), m_hostAddr, m_serverPort); // try to send the packet try ...{ send(pack); } catch (Exception exce) ...{// send fail exce.printStackTrace(m_errOut); return false; } // send success return true; } /** *//** * Send a specific acknowledgment. * * @param block * the sequence number of the packet. * @return if the packet send successful */ protected boolean sendAck(int block) ...{ // setup the ACK tag in packet m_bytesOut[0] = (byte) ((ACK >> 8) & 0xFF); m_bytesOut[1] = (byte) (ACK & 0xFF); // setup the sequence number in packet m_bytesOut[2] = (byte) ((block >> 8) & 0xFF); m_bytesOut[3] = (byte) (block & 0xFF); // setup the whole packet DatagramPacket pack = new DatagramPacket(m_bytesOut, 4, m_hostAddr, m_serverPort); // try to send the packet try ...{ send(pack); } catch (Exception exce) ...{// send fail exce.printStackTrace(m_errOut); return false; } // send success return true; } /** *//** * Send a packet (generic error or current block ACK) * * @param packType * packet type * @return if the packet send successful */ protected boolean sendPacket(int packType) ...{ // packet length int packLen = 2; // setup packet type tag in packet m_bytesOut[0] = (byte) ((packType >> 8) & 0xFF); m_bytesOut[1] = (byte) (packType & 0xFF); // deal with each type of packet switch (packType) ...{ case RRQ:// deal with RRQ packet case WRQ:// deal with WRQ packet // setup the file in packet System.arraycopy(m_fNameByte, 0, m_bytesOut, 2, m_fNameByte.length); m_bytesOut[2 + m_fNameByte.length] = 0; // setup the file type in packet System.arraycopy(m_fType, 0, m_bytesOut, 3 + m_fNameByte.length, m_fType.length); m_bytesOut[3 + m_fNameByte.length + m_fType.length] = 0; packLen += m_fNameByte.length + m_fType.length + 2; break; case DAT:// deal with DAT packet case ACK:// deal with ACK packet // setup sequence number in packet m_bytesOut[2] = (byte) ((m_block >> 8) & 0xFF); m_bytesOut[3] = (byte) (m_block & 0xFF); packLen += 2; // more for file if (packType == DAT) ...{// deal with DAT packet // file length int fLen; // file buffer byte[] fBuf = new byte[512]; try ...{// try to load the packet data fLen = m_fileIn.read(fBuf, 0, 512); } catch (IOException ioExce) ...{// load packet data fail fLen = 0;// assume EOF ioExce.printStackTrace(); } if (fLen < 0) /**//* * if load packet fail(like load empty file),the fLen will * be -1,then the array copy will fail,so turn it into zero */ fLen = 0; // copy the data into packet System.arraycopy(fBuf, 0, m_bytesOut, packLen, fLen); packLen += fLen; if (fLen != 512) m_EOF = true; } break; case ERR:// deal with ERR packet m_bytesOut[2] = m_bytesOut[3] = m_bytesOut[4] = 0; packLen = 5; break; default:// unknown packet type, send fail return false; } // setup the whole packet DatagramPacket pack = new DatagramPacket(m_bytesOut, packLen, m_hostAddr, m_serverPort); if (DEBUG) ...{// DEBUG information System.out.println("sending_packet " + pack.getAddress() + ":" + pack.getPort() + " packet_code=" + packType); } try ...{// try to send the packet send(pack); } catch (Exception exce) ...{// send fail exce.printStackTrace(m_errOut); return false; } // send success return true; } /** *//** * Process a received packet * * @return type of packet */ protected int rcvPacket() throws SocketException ...{ DatagramPacket pack = new DatagramPacket(m_bytesIn, 1024); // receive packet status boolean recStatus = false; try ...{// try to receive the packet receive(pack); recStatus = true; } catch (IOException ioExce) ...{ ioExce.printStackTrace(m_errOut); } if (!recStatus) return TIMEOUT; // deal with each type of packet m_serverPort = pack.getPort(); // data in the packet byte[] bytData = pack.getData(); // get the packet type int packType = (bytData[0] << 8) + bytData[1]; // the sequence number of block in the packet received if (DEBUG) ...{// DEBUG information System.out.println("packet receive " + pack.getAddress() + ":" + pack.getPort() + " packet code=" + packType); } int blockIn; switch (packType) ...{ case RRQ:// deal with RRQ packet case WRQ:// deal with RRQ packet // do nothing, things has been done in superior function return packType; case ACK:// check block # blockIn = (bytData[2] << 8) | (bytData[3] & 0xFF); if (DEBUG) ...{// DEBUG information System.out.println("block number=" + m_block + " blockIn number=" + blockIn); } if (blockIn != m_block) // block received is not the same as the socket (check fail) return NONE; ++m_block; return ACK; case DAT:// check block # and store blockIn = (bytData[2] << 8) | (bytData[3] & 0xFF); if (DEBUG) ...{// DEBUG information System.out.println("block numer=" + m_block + " blockIn number=" + blockIn); } if (blockIn > m_block)// some packet may be lost return UNKNOWN; if (blockIn < m_block) ...{// the ACK packet may lost, so send it again sendAck(blockIn); return NONE; } // block number matches try ...{ m_fileOut.write(bytData, 4, pack.getLength() - 4); } catch (IOException ioExce) ...{// write fail ioExce.printStackTrace(m_errOut); } // the file is end if (pack.getLength() < 516) m_EOF = true; // ACK current sendPacket(ACK); ++m_block; return DAT; case ERR:// do something with the error message String errMsg = new String(bytData, 4, pack.getLength()); m_errOut.println(errMsg); return ERR; default:// unknown packet type return UNKNOWN; } } /** *//** * Send a file * * @return send file success or not */ public boolean fsend() throws SocketException ...{ try ...{// try to get the file m_fileIn = new FileInputStream(m_fNameString); } catch (Exception exce) ...{// get the file fail exce.printStackTrace(m_errOut); return false; } // send success or not boolean rv; try ...{// try to send the packet // retry time int retry = 0; // set block number to 0 m_block = 0; rv = sendPacket(WRQ); if (!rv) // send fail return rv; // receive packet state int recState; while (!m_EOF) ...{ do ...{// send the packet until receive the ACK packet recState = rcvPacket(); if (recState == TIMEOUT) ...{ if (++retry > 5) // timeout too many times, send fail return false; if (m_block != 0) if (!sendPacket(DAT))// send the DAT packet again return false; continue; } // reset retry count retry = 0; if (recState == ERR)// receive error packet, send fail return false; if (recState == UNKNOWN) ...{// receive unknown packet, send // fail sendErrPacket(0, "Unknown error"); return false; } } while (recState != ACK); if (!sendPacket(DAT))// send packet fail return false; } // send success return true; } finally ...{// close the stream no matter what streamClose(m_fileIn); } } /** *//** * Get a file * * @return get file success or not */ public boolean freceive() throws SocketException ...{ // send success or not boolean rv; // receive packet state int recState; try ...{// try to save the file m_fileOut = new FileOutputStream(m_fNameString); } catch (Exception exce) ...{// save the file fail exce.printStackTrace(m_errOut); return false; } try ...{// try to receive the packet // retry time int retry = 0; // set the block number to 1 m_block = 1; rv = sendPacket(RRQ); if (!rv)// send packet fail return rv; while (!m_EOF) ...{ do ...{// try get the packet until receive the DAT packet recState = rcvPacket(); if (recState == TIMEOUT) ...{ if (++retry > 5)// timeout too many times, get fail return false; continue; } // reset retry count retry = 0; if (recState == ERR) // receive the ERR packet, get fail return false; if (recState == UNKNOWN) ...{// receive unknown packet, send // fail sendErrPacket(0, "Unknown error"); return false; } } while (recState != DAT); } // get success return true; } finally ...{// close stream in all cases if (!streamClose(m_fileOut)) return false; } } /** *//** * Handy function to close a file input stream. * * @param inStrem * the file input stream to close * @return close success or fail */ private boolean streamClose(FileInputStream fInStream) ...{ try ...{// try to close the stream fInStream.close(); } catch (Exception exce) ...{// close stream fail exce.printStackTrace(m_errOut); return false; } // close success return true; } /** *//** * Handy function to close a file output stream. * * @param fOutStream * the file output stream to close * @return success or fail */ private boolean streamClose(FileOutputStream fOutStream) ...{ try ...{// try to close the stream fOutStream.close(); } catch (Exception exce) ...{// close stream fail exce.printStackTrace(m_errOut); } // send success return true; } /** *//** * Server thread */ public void run() ...{ if (m_serverCode == WRQ) ...{// deal with the WRQ request try ...{// try setup the output stream m_fileOut = new FileOutputStream(m_fNameString); } catch (IOException exce) ...{// can't get the file sendErrPacket(2, "Access violation"); return; } // send ACK 0 sendAck(0); // set block number to 1 m_block = 1; // wait for DATA int recState;// receive state do ...{// while the file is not end receive the packet try ...{// try receive the packet recState = rcvPacket(); } catch (SocketException sockExce) ...{// receive fail sockExce.printStackTrace(); recState = ERR; } if (recState == ERR) ...{ // close the output stream streamClose(m_fileOut); return; } if (recState != DAT && recState != NONE) ...{ // close the output stream streamClose(m_fileOut); sendErrPacket(0, "?"); return; } } while (!m_EOF); // close the output stream streamClose(m_fileOut); } if (m_serverCode == RRQ) ...{// deal with RRQ packet try ...{// try to setup input stream m_fileIn = new FileInputStream(m_fNameString); } catch (IOException ioExce) ...{// can't get the file if (DEBUG) ...{// DEBUG information ioExce.printStackTrace(m_errOut); } sendErrPacket(1, "File not found."); return; } // send DATA m_block = 1; // retry time int retry = 0; do ...{ int recState; if (!sendPacket(DAT)) ...{// send packet fail sendErrPacket(0, "?"); // close the input stream streamClose(m_fileIn); return; } do ...{ try ...{// try to get the ACK recState = rcvPacket(); } catch (SocketException sockExce) ...{ sockExce.printStackTrace(m_errOut); recState = ERR; } if (recState == ERR) ...{ // close the input stream streamClose(m_fileIn); return; } if (recState == UNKNOWN || recState == RRQ || recState == WRQ || recState == DAT) ...{ sendErrPacket(4, "Illegal"); // close the input stream streamClose(m_fileIn); return; } if (recState == TIMEOUT && ++retry > 5) ...{ // time out and retry too many times sendErrPacket(0, "TIMEOUT"); // close the input stream streamClose(m_fileIn); return; } if (recState == ACK) ...{ // ++m_block; // reset retry count to 0 retry = 0; } } while (recState != ACK && recState != TIMEOUT); } while (!m_EOF); // close the output stream streamClose(m_fileIn); } } /** *//** * Interface for server */ public static void tftpd() ...{ DatagramSocket serSock; try ...{ serSock = new DatagramSocket(69); } catch (SocketException sockExce) ...{ System.out.print("Unable to start server:" + sockExce); return; } byte[] buf = new byte[1024]; DatagramPacket pack = new DatagramPacket(buf, 1024); while (true) ...{ try ...{// wait for WRQ or RRQ -- all others are errors serSock.setSoTimeout(0); serSock.receive(pack); byte[] data = pack.getData(); int packType = (data[0] << 8) + data[1]; if (DEBUG) ...{// DEBUG information System.out .println("receive packet " + pack.getAddress() + ":" + pack.getPort() + " packet code=" + packType); } if (packType != WRQ && packType != RRQ) ...{ // send back error packet byte[] errBytes = new byte[5]; errBytes[0] = (byte) ((ERR >> 8) & 0xFF); errBytes[1] = (byte) (ERR & 0xFF); errBytes[2] = (byte) 0; errBytes[3] = (byte) 0; errBytes[4] = 0; pack.setData(errBytes); serSock.send(pack); continue; } // start new thread (use private constructor) TftpSocket worker = new TftpSocket(); // file name length and file type length int zlen, zlen1; worker.m_serverPort = pack.getPort(); worker.m_hostAddr = pack.getAddress(); // get the file name from packet data for (zlen = 0; data[zlen + 2] != 0; ++zlen) ; worker.m_fNameString = new String(data, 2, zlen); worker.m_fNameByte = worker.m_fNameString.getBytes(); // get the file type from packet data for (zlen1 = 0; data[zlen1 + 3 + zlen] != 0; ++zlen1) ; worker.m_fType = new String(data, zlen + 3, zlen1).getBytes(); worker.m_serverCode = packType; // start server thread new Thread(worker).start(); } catch (IOException exce) ...{ // ignore exce.printStackTrace(); } } } /** *//** * Test main. provide file name, file type, host on command line follow with * an S to send R(or nothing) to receive */ public static void main(String[] args) throws Exception ...{ if (args.length == 0) ...{ System.out.println("Starting server"); new Tftpd().start(); return; } TftpSocket sock = new TftpSocket(args[0], args[1], args[2]); if (args.length <= 3 || !args[3].equals("S")) ...{ System.out.println("Client request " + sock.freceive()); } else ...{ System.out.println("Client request " + sock.fsend()); } } /** *//** * Helper thread for test main */ static class Tftpd extends Thread ...{ public void run() ...{ TftpSocket.tftpd(); } }}
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