1/*
2 * Copyright (c) 2000, 2013, 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
32package sun.security.krb5.internal;
33
34import java.io.*;
35import java.net.*;
36import sun.security.util.IOUtils;
37
38public abstract class NetClient implements AutoCloseable {
39    public static NetClient getInstance(String protocol, String hostname, int port,
40            int timeout) throws IOException {
41        if (protocol.equals("TCP")) {
42            return new TCPClient(hostname, port, timeout);
43        } else {
44            return new UDPClient(hostname, port, timeout);
45        }
46    }
47
48    abstract public void send(byte[] data) throws IOException;
49    abstract public byte[] receive() throws IOException;
50    abstract public void close() throws IOException;
51}
52
53class TCPClient extends NetClient {
54
55    private Socket tcpSocket;
56    private BufferedOutputStream out;
57    private BufferedInputStream in;
58
59    TCPClient(String hostname, int port, int timeout)
60            throws IOException {
61        tcpSocket = new Socket();
62        tcpSocket.connect(new InetSocketAddress(hostname, port), timeout);
63        out = new BufferedOutputStream(tcpSocket.getOutputStream());
64        in = new BufferedInputStream(tcpSocket.getInputStream());
65        tcpSocket.setSoTimeout(timeout);
66    }
67
68    @Override
69    public void send(byte[] data) throws IOException {
70        byte[] lenField = new byte[4];
71        intToNetworkByteOrder(data.length, lenField, 0, 4);
72        out.write(lenField);
73
74        out.write(data);
75        out.flush();
76    }
77
78    @Override
79    public byte[] receive() throws IOException {
80        byte[] lenField = new byte[4];
81        int count = readFully(lenField, 4);
82
83        if (count != 4) {
84            if (Krb5.DEBUG) {
85                System.out.println(
86                    ">>>DEBUG: TCPClient could not read length field");
87            }
88            return null;
89        }
90
91        int len = networkByteOrderToInt(lenField, 0, 4);
92        if (Krb5.DEBUG) {
93            System.out.println(
94                ">>>DEBUG: TCPClient reading " + len + " bytes");
95        }
96        if (len <= 0) {
97            if (Krb5.DEBUG) {
98                System.out.println(
99                    ">>>DEBUG: TCPClient zero or negative length field: "+len);
100            }
101            return null;
102        }
103
104        try {
105            return IOUtils.readFully(in, len, true);
106        } catch (IOException ioe) {
107            if (Krb5.DEBUG) {
108                System.out.println(
109                    ">>>DEBUG: TCPClient could not read complete packet (" +
110                    len + "/" + count + ")");
111            }
112            return null;
113        }
114    }
115
116    @Override
117    public void close() throws IOException {
118        tcpSocket.close();
119    }
120
121    /**
122     * Read requested number of bytes before returning.
123     * @return The number of bytes actually read; -1 if none read
124     */
125    private int readFully(byte[] inBuf, int total) throws IOException {
126        int count, pos = 0;
127
128        while (total > 0) {
129            count = in.read(inBuf, pos, total);
130
131            if (count == -1) {
132                return (pos == 0? -1 : pos);
133            }
134            pos += count;
135            total -= count;
136        }
137        return pos;
138    }
139
140    /**
141     * Returns the integer represented by 4 bytes in network byte order.
142     */
143    private static int networkByteOrderToInt(byte[] buf, int start,
144        int count) {
145        if (count > 4) {
146            throw new IllegalArgumentException(
147                "Cannot handle more than 4 bytes");
148        }
149
150        int answer = 0;
151
152        for (int i = 0; i < count; i++) {
153            answer <<= 8;
154            answer |= ((int)buf[start+i] & 0xff);
155        }
156        return answer;
157    }
158
159    /**
160     * Encodes an integer into 4 bytes in network byte order in the buffer
161     * supplied.
162     */
163    private static void intToNetworkByteOrder(int num, byte[] buf,
164        int start, int count) {
165        if (count > 4) {
166            throw new IllegalArgumentException(
167                "Cannot handle more than 4 bytes");
168        }
169
170        for (int i = count-1; i >= 0; i--) {
171            buf[start+i] = (byte)(num & 0xff);
172            num >>>= 8;
173        }
174    }
175}
176
177class UDPClient extends NetClient {
178    InetAddress iaddr;
179    int iport;
180    int bufSize = 65507;
181    DatagramSocket dgSocket;
182    DatagramPacket dgPacketIn;
183
184    UDPClient(String hostname, int port, int timeout)
185        throws UnknownHostException, SocketException {
186        iaddr = InetAddress.getByName(hostname);
187        iport = port;
188        dgSocket = new DatagramSocket();
189        dgSocket.setSoTimeout(timeout);
190        dgSocket.connect(iaddr, iport);
191    }
192
193    @Override
194    public void send(byte[] data) throws IOException {
195        DatagramPacket dgPacketOut = new DatagramPacket(data, data.length,
196                                                        iaddr, iport);
197        dgSocket.send(dgPacketOut);
198    }
199
200    @Override
201    public byte[] receive() throws IOException {
202        byte[] ibuf = new byte[bufSize];
203        dgPacketIn = new DatagramPacket(ibuf, ibuf.length);
204        try {
205            dgSocket.receive(dgPacketIn);
206        }
207        catch (SocketException e) {
208            if (e instanceof PortUnreachableException) {
209                throw e;
210            }
211            dgSocket.receive(dgPacketIn);
212        }
213        byte[] data = new byte[dgPacketIn.getLength()];
214        System.arraycopy(dgPacketIn.getData(), 0, data, 0,
215                         dgPacketIn.getLength());
216        return data;
217    }
218
219    @Override
220    public void close() {
221        dgSocket.close();
222    }
223}
224