1 /*
2 * Copyright (c) 2020, 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.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24 /* @test
25 * @bug 8053479
26 * @run main Truncate
27 * @summary Test DatagramChannel receive/read where there are fewer bytes remaining
28 * in the buffer than are required to hold the datagram. The remainder of the
29 * datagram should be silently discarded.
30 */
31
32 import java.io.IOException;
33 import java.net.InetAddress;
34 import java.net.InetSocketAddress;
35 import java.net.SocketAddress;
36 import java.nio.ByteBuffer;
37 import java.nio.channels.DatagramChannel;
38 import java.util.Arrays;
39 import java.util.stream.IntStream;
40
41 public class Truncate {
42 static final int LARGE_SIZE = 1000;
43 static final int SMALL_SIZE = 100;
44
45 public static void main(String[] args) throws Exception {
46 try (DatagramChannel dc = DatagramChannel.open()) {
47 dc.bind(new InetSocketAddress(InetAddress.getLoopbackAddress(), 0));
48
49 // not connected
50 testReceiveDiscards(dc);
51
52 // connected
53 dc.connect(dc.getLocalAddress());
54 testReceiveDiscards(dc);
55 testReadDiscards(dc);
56 testScatteringReadDiscards(dc);
57 }
58 }
59
60 /**
61 * Receive a datagram with a buffer that has fewer bytes remaining than are
62 * required to hold the datagram.
63 */
64 static void testReceiveDiscards(DatagramChannel dc) throws IOException {
65 ByteBuffer largeBuffer = send(dc, LARGE_SIZE, dc.getLocalAddress());
66
67 ByteBuffer smallBuffer = ByteBuffer.allocate(SMALL_SIZE);
68 SocketAddress sender = dc.receive(smallBuffer);
69 assertTrue(sender.equals(dc.getLocalAddress()));
70
71 // check buffer/contents
72 smallBuffer.flip();
73 assertTrue(smallBuffer.remaining() == SMALL_SIZE);
74 assertTrue(Arrays.equals(smallBuffer.array(), 0, SMALL_SIZE,
75 largeBuffer.array(), 0, SMALL_SIZE));
76 }
77
78 /**
79 * Read a datagram with a buffer that has fewer bytes remaining than are
80 * required to hold the datagram.
81 */
82 static void testReadDiscards(DatagramChannel dc) throws IOException {
83 ByteBuffer largeBuffer = send(dc, LARGE_SIZE, dc.getRemoteAddress());
84
85 ByteBuffer smallBuffer = ByteBuffer.allocate(SMALL_SIZE);
86 int n = dc.read(smallBuffer);
87 assertTrue(n == SMALL_SIZE);
88
89 // check buffer/contents
90 smallBuffer.flip();
91 assertTrue(smallBuffer.remaining() == SMALL_SIZE);
92 assertTrue(Arrays.equals(smallBuffer.array(), 0, SMALL_SIZE,
93 largeBuffer.array(), 0, SMALL_SIZE));
94 }
95
96 /**
97 * Read a datagram with an array of buffers that have fewer bytes remaining
98 * than are required to hold the datagram.
99 */
100 static void testScatteringReadDiscards(DatagramChannel dc) throws IOException {
101 ByteBuffer largeBuffer = send(dc, LARGE_SIZE, dc.getRemoteAddress());
102
103 ByteBuffer smallBuffer1 = ByteBuffer.allocate(SMALL_SIZE);
104 ByteBuffer smallBuffer2 = ByteBuffer.allocate(SMALL_SIZE);
105 ByteBuffer[] bufs = new ByteBuffer[] { smallBuffer1, smallBuffer2 };
106 long n = dc.read(bufs);
107 assertTrue(n == (SMALL_SIZE * bufs.length));
108
109 // check buffer/contents
110 smallBuffer1.flip();
111 assertTrue(smallBuffer1.remaining() == SMALL_SIZE);
112 assertTrue(Arrays.equals(smallBuffer1.array(), 0, SMALL_SIZE,
113 largeBuffer.array(), 0, SMALL_SIZE));
114 smallBuffer2.flip();
115 assertTrue(smallBuffer2.remaining() == SMALL_SIZE);
116 assertTrue(Arrays.equals(smallBuffer2.array(), 0, SMALL_SIZE,
117 largeBuffer.array(), SMALL_SIZE, SMALL_SIZE << 1));
118 }
119
120 /**
121 * Send a datagram of the given size to the given target address.
122 * @return the buffer with the datagram sent to the target address
123 */
124 static ByteBuffer send(DatagramChannel dc, int size, SocketAddress target)
125 throws IOException
126 {
127 ByteBuffer buffer = ByteBuffer.allocate(size);
128 IntStream.range(0, size).forEach(i -> buffer.put((byte)i));
129 buffer.flip();
130
131 int n = dc.send(buffer, target);
132 assertTrue(n == size);
133 buffer.flip();
134 return buffer;
135 }
136
137 static void assertTrue(boolean e) {
138 if (!e) throw new RuntimeException();
139 }
140 }