1 /*

     2  * Copyright (c) 2000, 2003, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 /*

    27  *

    28  *  (C) Copyright IBM Corp. 1999 All Rights Reserved.

    29  *  Copyright 1997 The Open Group Research Institute.  All rights reserved.

    30  */

    31 

    32 package sun.security.krb5.internal;

    33 

    34 import java.io.*;

    35 import java.net.*;

    36 

    37 public class TCPClient {

    38 

    39     private Socket tcpSocket;

    40     private BufferedOutputStream out;

    41     private BufferedInputStream in;

    42 

    43     public TCPClient(String hostname, int port) throws IOException {

    44         tcpSocket = new Socket(hostname, port);

    45         out = new BufferedOutputStream(tcpSocket.getOutputStream());

    46         in = new BufferedInputStream(tcpSocket.getInputStream());

    47     }

    48 

    49     public void send(byte[] data) throws IOException {

    50         byte[] lenField = new byte[4];

    51         intToNetworkByteOrder(data.length, lenField, 0, 4);

    52         out.write(lenField);

    53 

    54         out.write(data);

    55         out.flush();

    56     }

    57 

    58     public byte[] receive() throws IOException {

    59         byte[] lenField = new byte[4];

    60         int count = readFully(lenField, 4);

    61 

    62         if (count != 4) {

    63             if (Krb5.DEBUG) {

    64                 System.out.println(

    65                     ">>>DEBUG: TCPClient could not read length field");

    66             }

    67             return null;

    68         }

    69 

    70         int len = networkByteOrderToInt(lenField, 0, 4);

    71         if (Krb5.DEBUG) {

    72             System.out.println(

    73                 ">>>DEBUG: TCPClient reading " + len + " bytes");

    74         }

    75         if (len <= 0) {

    76             if (Krb5.DEBUG) {

    77                 System.out.println(

    78                     ">>>DEBUG: TCPClient zero or negative length field: "+len);

    79             }

    80             return null;

    81         }

    82 

    83         byte data[] = new byte[len];

    84         count = readFully(data, len);

    85         if (count != len) {

    86             if (Krb5.DEBUG) {

    87                 System.out.println(

    88                     ">>>DEBUG: TCPClient could not read complete packet (" +

    89                     len + "/" + count + ")");

    90             }

    91             return null;

    92         } else {

    93             return data;

    94         }

    95     }

    96 

    97     public void close() throws IOException {

    98         tcpSocket.close();

    99     }

   100 

   101     /**

   102      * Read requested number of bytes before returning.

   103      * @return The number of bytes actually read; -1 if none read

   104      */

   105     private int readFully(byte[] inBuf, int total) throws IOException {

   106         int count, pos = 0;

   107 

   108         while (total > 0) {

   109             count = in.read(inBuf, pos, total);

   110 

   111             if (count == -1) {

   112                 return (pos == 0? -1 : pos);

   113             }

   114             pos += count;

   115             total -= count;

   116         }

   117         return pos;

   118     }

   119 

   120     /**

   121      * Returns the integer represented by 4 bytes in network byte order.

   122      */

   123     private static final int networkByteOrderToInt(byte[] buf, int start,

   124         int count) {

   125         if (count > 4) {

   126             throw new IllegalArgumentException(

   127                 "Cannot handle more than 4 bytes");

   128         }

   129 

   130         int answer = 0;

   131 

   132         for (int i = 0; i < count; i++) {

   133             answer <<= 8;

   134             answer |= ((int)buf[start+i] & 0xff);

   135         }

   136         return answer;

   137     }

   138 

   139     /**

   140      * Encodes an integer into 4 bytes in network byte order in the buffer

   141      * supplied.

   142      */

   143     private static final void intToNetworkByteOrder(int num, byte[] buf,

   144         int start, int count) {

   145         if (count > 4) {

   146             throw new IllegalArgumentException(

   147                 "Cannot handle more than 4 bytes");

   148         }

   149 

   150         for (int i = count-1; i >= 0; i--) {

   151             buf[start+i] = (byte)(num & 0xff);

   152             num >>>= 8;

   153         }

   154     }

   155 }