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| 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 | +} |
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