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| 1 | /* | ||
| 2 | * Copyright (c) 2007, 2009, 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 | package java.net; | ||
| 27 | |||
| 28 | /** | ||
| 29 | * Defines the <em>standard</em> socket options. | ||
| 30 | * | ||
| 31 | * <p> The {@link SocketOption#name name} of each socket option defined by this | ||
| 32 | * class is its field name. | ||
| 33 | * | ||
| 34 | * <p> In this release, the socket options defined here are used by {@link | ||
| 35 | * java.nio.channels.NetworkChannel network} channels in the {@link | ||
| 36 | * java.nio.channels channels} package. | ||
| 37 | * | ||
| 38 | * @since 1.7 | ||
| 39 | */ | ||
| 40 | |||
| 41 | public final class StandardSocketOptions { | ||
| 42 | private StandardSocketOptions() { } | ||
| 43 | |||
| 44 | // -- SOL_SOCKET -- | ||
| 45 | |||
| 46 | /** | ||
| 47 | * Allow transmission of broadcast datagrams. | ||
| 48 | * | ||
| 49 | * <p> The value of this socket option is a {@code Boolean} that represents | ||
| 50 | * whether the option is enabled or disabled. The option is specific to | ||
| 51 | * datagram-oriented sockets sending to {@link java.net.Inet4Address IPv4} | ||
| 52 | * broadcast addresses. When the socket option is enabled then the socket | ||
| 53 | * can be used to send <em>broadcast datagrams</em>. | ||
| 54 | * | ||
| 55 | * <p> The initial value of this socket option is {@code FALSE}. The socket | ||
| 56 | * option may be enabled or disabled at any time. Some operating systems may | ||
| 57 | * require that the Java virtual machine be started with implementation | ||
| 58 | * specific privileges to enable this option or send broadcast datagrams. | ||
| 59 | * | ||
| 60 | * @see <a href="http://www.ietf.org/rfc/rfc919.txt">RFC 929: | ||
| 61 | * Broadcasting Internet Datagrams</a> | ||
| 62 | * @see DatagramSocket#setBroadcast | ||
| 63 | */ | ||
| 64 | public static final SocketOption<Boolean> SO_BROADCAST = | ||
| 65 | new StdSocketOption<Boolean>("SO_BROADCAST", Boolean.class); | ||
| 66 | |||
| 67 | /** | ||
| 68 | * Keep connection alive. | ||
| 69 | * | ||
| 70 | * <p> The value of this socket option is a {@code Boolean} that represents | ||
| 71 | * whether the option is enabled or disabled. When the {@code SO_KEEPALIVE} | ||
| 72 | * option is enabled the operating system may use a <em>keep-alive</em> | ||
| 73 | * mechanism to periodically probe the other end of a connection when the | ||
| 74 | * connection is otherwise idle. The exact semantics of the keep alive | ||
| 75 | * mechanism is system dependent and therefore unspecified. | ||
| 76 | * | ||
| 77 | * <p> The initial value of this socket option is {@code FALSE}. The socket | ||
| 78 | * option may be enabled or disabled at any time. | ||
| 79 | * | ||
| 80 | * @see <a href="http://www.ietf.org/rfc/rfc1122.txt">RFC 1122 | ||
| 81 | * Requirements for Internet Hosts -- Communication Layers</a> | ||
| 82 | * @see Socket#setKeepAlive | ||
| 83 | */ | ||
| 84 | public static final SocketOption<Boolean> SO_KEEPALIVE = | ||
| 85 | new StdSocketOption<Boolean>("SO_KEEPALIVE", Boolean.class); | ||
| 86 | |||
| 87 | /** | ||
| 88 | * The size of the socket send buffer. | ||
| 89 | * | ||
| 90 | * <p> The value of this socket option is an {@code Integer} that is the | ||
| 91 | * size of the socket send buffer in bytes. The socket send buffer is an | ||
| 92 | * output buffer used by the networking implementation. It may need to be | ||
| 93 | * increased for high-volume connections. The value of the socket option is | ||
| 94 | * a <em>hint</em> to the implementation to size the buffer and the actual | ||
| 95 | * size may differ. The socket option can be queried to retrieve the actual | ||
| 96 | * size. | ||
| 97 | * | ||
| 98 | * <p> For datagram-oriented sockets, the size of the send buffer may limit | ||
| 99 | * the size of the datagrams that may be sent by the socket. Whether | ||
| 100 | * datagrams larger than the buffer size are sent or discarded is system | ||
| 101 | * dependent. | ||
| 102 | * | ||
| 103 | * <p> The initial/default size of the socket send buffer and the range of | ||
| 104 | * allowable values is system dependent although a negative size is not | ||
| 105 | * allowed. An attempt to set the socket send buffer to larger than its | ||
| 106 | * maximum size causes it to be set to its maximum size. | ||
| 107 | * | ||
| 108 | * <p> An implementation allows this socket option to be set before the | ||
| 109 | * socket is bound or connected. Whether an implementation allows the | ||
| 110 | * socket send buffer to be changed after the socket is bound is system | ||
| 111 | * dependent. | ||
| 112 | * | ||
| 113 | * @see Socket#setSendBufferSize | ||
| 114 | */ | ||
| 115 | public static final SocketOption<Integer> SO_SNDBUF = | ||
| 116 | new StdSocketOption<Integer>("SO_SNDBUF", Integer.class); | ||
| 117 | |||
| 118 | |||
| 119 | /** | ||
| 120 | * The size of the socket receive buffer. | ||
| 121 | * | ||
| 122 | * <p> The value of this socket option is an {@code Integer} that is the | ||
| 123 | * size of the socket receive buffer in bytes. The socket receive buffer is | ||
| 124 | * an input buffer used by the networking implementation. It may need to be | ||
| 125 | * increased for high-volume connections or decreased to limit the possible | ||
| 126 | * backlog of incoming data. The value of the socket option is a | ||
| 127 | * <em>hint</em> to the implementation to size the buffer and the actual | ||
| 128 | * size may differ. | ||
| 129 | * | ||
| 130 | * <p> For datagram-oriented sockets, the size of the receive buffer may | ||
| 131 | * limit the size of the datagrams that can be received. Whether datagrams | ||
| 132 | * larger than the buffer size can be received is system dependent. | ||
| 133 | * Increasing the socket receive buffer may be important for cases where | ||
| 134 | * datagrams arrive in bursts faster than they can be processed. | ||
| 135 | * | ||
| 136 | * <p> In the case of stream-oriented sockets and the TCP/IP protocol, the | ||
| 137 | * size of the socket receive buffer may be used when advertising the size | ||
| 138 | * of the TCP receive window to the remote peer. | ||
| 139 | * | ||
| 140 | * <p> The initial/default size of the socket receive buffer and the range | ||
| 141 | * of allowable values is system dependent although a negative size is not | ||
| 142 | * allowed. An attempt to set the socket receive buffer to larger than its | ||
| 143 | * maximum size causes it to be set to its maximum size. | ||
| 144 | * | ||
| 145 | * <p> An implementation allows this socket option to be set before the | ||
| 146 | * socket is bound or connected. Whether an implementation allows the | ||
| 147 | * socket receive buffer to be changed after the socket is bound is system | ||
| 148 | * dependent. | ||
| 149 | * | ||
| 150 | * @see <a href="http://www.ietf.org/rfc/rfc1323.txt">RFC 1323: TCP | ||
| 151 | * Extensions for High Performance</a> | ||
| 152 | * @see Socket#setReceiveBufferSize | ||
| 153 | * @see ServerSocket#setReceiveBufferSize | ||
| 154 | */ | ||
| 155 | public static final SocketOption<Integer> SO_RCVBUF = | ||
| 156 | new StdSocketOption<Integer>("SO_RCVBUF", Integer.class); | ||
| 157 | |||
| 158 | /** | ||
| 159 | * Re-use address. | ||
| 160 | * | ||
| 161 | * <p> The value of this socket option is a {@code Boolean} that represents | ||
| 162 | * whether the option is enabled or disabled. The exact semantics of this | ||
| 163 | * socket option are socket type and system dependent. | ||
| 164 | * | ||
| 165 | * <p> In the case of stream-oriented sockets, this socket option will | ||
| 166 | * usually determine whether the socket can be bound to a socket address | ||
| 167 | * when a previous connection involving that socket address is in the | ||
| 168 | * <em>TIME_WAIT</em> state. On implementations where the semantics differ, | ||
| 169 | * and the socket option is not required to be enabled in order to bind the | ||
| 170 | * socket when a previous connection is in this state, then the | ||
| 171 | * implementation may choose to ignore this option. | ||
| 172 | * | ||
| 173 | * <p> For datagram-oriented sockets the socket option is used to allow | ||
| 174 | * multiple programs bind to the same address. This option should be enabled | ||
| 175 | * when the socket is to be used for Internet Protocol (IP) multicasting. | ||
| 176 | * | ||
| 177 | * <p> An implementation allows this socket option to be set before the | ||
| 178 | * socket is bound or connected. Changing the value of this socket option | ||
| 179 | * after the socket is bound has no effect. The default value of this | ||
| 180 | * socket option is system dependent. | ||
| 181 | * | ||
| 182 | * @see <a href="http://www.ietf.org/rfc/rfc793.txt">RFC 793: Transmission | ||
| 183 | * Control Protocol</a> | ||
| 184 | * @see ServerSocket#setReuseAddress | ||
| 185 | */ | ||
| 186 | public static final SocketOption<Boolean> SO_REUSEADDR = | ||
| 187 | new StdSocketOption<Boolean>("SO_REUSEADDR", Boolean.class); | ||
| 188 | |||
| 189 | /** | ||
| 190 | * Linger on close if data is present. | ||
| 191 | * | ||
| 192 | * <p> The value of this socket option is an {@code Integer} that controls | ||
| 193 | * the action taken when unsent data is queued on the socket and a method | ||
| 194 | * to close the socket is invoked. If the value of the socket option is zero | ||
| 195 | * or greater, then it represents a timeout value, in seconds, known as the | ||
| 196 | * <em>linger interval</em>. The linger interval is the timeout for the | ||
| 197 | * {@code close} method to block while the operating system attempts to | ||
| 198 | * transmit the unsent data or it decides that it is unable to transmit the | ||
| 199 | * data. If the value of the socket option is less than zero then the option | ||
| 200 | * is disabled. In that case the {@code close} method does not wait until | ||
| 201 | * unsent data is transmitted; if possible the operating system will transmit | ||
| 202 | * any unsent data before the connection is closed. | ||
| 203 | * | ||
| 204 | * <p> This socket option is intended for use with sockets that are configured | ||
| 205 | * in {@link java.nio.channels.SelectableChannel#isBlocking() blocking} mode | ||
| 206 | * only. The behavior of the {@code close} method when this option is | ||
| 207 | * enabled on a non-blocking socket is not defined. | ||
| 208 | * | ||
| 209 | * <p> The initial value of this socket option is a negative value, meaning | ||
| 210 | * that the option is disabled. The option may be enabled, or the linger | ||
| 211 | * interval changed, at any time. The maximum value of the linger interval | ||
| 212 | * is system dependent. Setting the linger interval to a value that is | ||
| 213 | * greater than its maximum value causes the linger interval to be set to | ||
| 214 | * its maximum value. | ||
| 215 | * | ||
| 216 | * @see Socket#setSoLinger | ||
| 217 | */ | ||
| 218 | public static final SocketOption<Integer> SO_LINGER = | ||
| 219 | new StdSocketOption<Integer>("SO_LINGER", Integer.class); | ||
| 220 | |||
| 221 | |||
| 222 | // -- IPPROTO_IP -- | ||
| 223 | |||
| 224 | /** | ||
| 225 | * The Type of Service (ToS) octet in the Internet Protocol (IP) header. | ||
| 226 | * | ||
| 227 | * <p> The value of this socket option is an {@code Integer} representing | ||
| 228 | * the value of the ToS octet in IP packets sent by sockets to an {@link | ||
| 229 | * StandardProtocolFamily#INET IPv4} socket. The interpretation of the ToS | ||
| 230 | * octet is network specific and is not defined by this class. Further | ||
| 231 | * information on the ToS octet can be found in <a | ||
| 232 | * href="http://www.ietf.org/rfc/rfc1349.txt">RFC 1349</a> and <a | ||
| 233 | * href="http://www.ietf.org/rfc/rfc2474.txt">RFC 2474</a>. The value | ||
| 234 | * of the socket option is a <em>hint</em>. An implementation may ignore the | ||
| 235 | * value, or ignore specific values. | ||
| 236 | * | ||
| 237 | * <p> The initial/default value of the TOS field in the ToS octet is | ||
| 238 | * implementation specific but will typically be {@code 0}. For | ||
| 239 | * datagram-oriented sockets the option may be configured at any time after | ||
| 240 | * the socket has been bound. The new value of the octet is used when sending | ||
| 241 | * subsequent datagrams. It is system dependent whether this option can be | ||
| 242 | * queried or changed prior to binding the socket. | ||
| 243 | * | ||
| 244 | * <p> The behavior of this socket option on a stream-oriented socket, or an | ||
| 245 | * {@link StandardProtocolFamily#INET6 IPv6} socket, is not defined in this | ||
| 246 | * release. | ||
| 247 | * | ||
| 248 | * @see DatagramSocket#setTrafficClass | ||
| 249 | */ | ||
| 250 | public static final SocketOption<Integer> IP_TOS = | ||
| 251 | new StdSocketOption<Integer>("IP_TOS", Integer.class); | ||
| 252 | |||
| 253 | /** | ||
| 254 | * The network interface for Internet Protocol (IP) multicast datagrams. | ||
| 255 | * | ||
| 256 | * <p> The value of this socket option is a {@link NetworkInterface} that | ||
| 257 | * represents the outgoing interface for multicast datagrams sent by the | ||
| 258 | * datagram-oriented socket. For {@link StandardProtocolFamily#INET6 IPv6} | ||
| 259 | * sockets then it is system dependent whether setting this option also | ||
| 260 | * sets the outgoing interface for multlicast datagrams sent to IPv4 | ||
| 261 | * addresses. | ||
| 262 | * | ||
| 263 | * <p> The initial/default value of this socket option may be {@code null} | ||
| 264 | * to indicate that outgoing interface will be selected by the operating | ||
| 265 | * system, typically based on the network routing tables. An implementation | ||
| 266 | * allows this socket option to be set after the socket is bound. Whether | ||
| 267 | * the socket option can be queried or changed prior to binding the socket | ||
| 268 | * is system dependent. | ||
| 269 | * | ||
| 270 | * @see java.nio.channels.MulticastChannel | ||
| 271 | * @see MulticastSocket#setInterface | ||
| 272 | */ | ||
| 273 | public static final SocketOption<NetworkInterface> IP_MULTICAST_IF = | ||
| 274 | new StdSocketOption<NetworkInterface>("IP_MULTICAST_IF", NetworkInterface.class); | ||
| 275 | |||
| 276 | /** | ||
| 277 | * The <em>time-to-live</em> for Internet Protocol (IP) multicast datagrams. | ||
| 278 | * | ||
| 279 | * <p> The value of this socket option is an {@code Integer} in the range | ||
| 280 | * <tt>0 <= value <= 255</tt>. It is used to control | ||
| 281 | * the scope of multicast datagrams sent by the datagram-oriented socket. | ||
| 282 | * In the case of an {@link StandardProtocolFamily#INET IPv4} socket | ||
| 283 | * the option is the time-to-live (TTL) on multicast datagrams sent by the | ||
| 284 | * socket. Datagrams with a TTL of zero are not transmitted on the network | ||
| 285 | * but may be delivered locally. In the case of an {@link | ||
| 286 | * StandardProtocolFamily#INET6 IPv6} socket the option is the | ||
| 287 | * <em>hop limit</em> which is number of <em>hops</em> that the datagram can | ||
| 288 | * pass through before expiring on the network. For IPv6 sockets it is | ||
| 289 | * system dependent whether the option also sets the <em>time-to-live</em> | ||
| 290 | * on multicast datagrams sent to IPv4 addresses. | ||
| 291 | * | ||
| 292 | * <p> The initial/default value of the time-to-live setting is typically | ||
| 293 | * {@code 1}. An implementation allows this socket option to be set after | ||
| 294 | * the socket is bound. Whether the socket option can be queried or changed | ||
| 295 | * prior to binding the socket is system dependent. | ||
| 296 | * | ||
| 297 | * @see java.nio.channels.MulticastChannel | ||
| 298 | * @see MulticastSocket#setTimeToLive | ||
| 299 | */ | ||
| 300 | public static final SocketOption<Integer> IP_MULTICAST_TTL = | ||
| 301 | new StdSocketOption<Integer>("IP_MULTICAST_TTL", Integer.class); | ||
| 302 | |||
| 303 | /** | ||
| 304 | * Loopback for Internet Protocol (IP) multicast datagrams. | ||
| 305 | * | ||
| 306 | * <p> The value of this socket option is a {@code Boolean} that controls | ||
| 307 | * the <em>loopback</em> of multicast datagrams. The value of the socket | ||
| 308 | * option represents if the option is enabled or disabled. | ||
| 309 | * | ||
| 310 | * <p> The exact semantics of this socket options are system dependent. | ||
| 311 | * In particular, it is system dependent whether the loopback applies to | ||
| 312 | * multicast datagrams sent from the socket or received by the socket. | ||
| 313 | * For {@link StandardProtocolFamily#INET6 IPv6} sockets then it is | ||
| 314 | * system dependent whether the option also applies to multicast datagrams | ||
| 315 | * sent to IPv4 addresses. | ||
| 316 | * | ||
| 317 | * <p> The initial/default value of this socket option is {@code TRUE}. An | ||
| 318 | * implementation allows this socket option to be set after the socket is | ||
| 319 | * bound. Whether the socket option can be queried or changed prior to | ||
| 320 | * binding the socket is system dependent. | ||
| 321 | * | ||
| 322 | * @see java.nio.channels.MulticastChannel | ||
| 323 | * @see MulticastSocket#setLoopbackMode | ||
| 324 | */ | ||
| 325 | public static final SocketOption<Boolean> IP_MULTICAST_LOOP = | ||
| 326 | new StdSocketOption<Boolean>("IP_MULTICAST_LOOP", Boolean.class); | ||
| 327 | |||
| 328 | |||
| 329 | // -- IPPROTO_TCP -- | ||
| 330 | |||
| 331 | /** | ||
| 332 | * Disable the Nagle algorithm. | ||
| 333 | * | ||
| 334 | * <p> The value of this socket option is a {@code Boolean} that represents | ||
| 335 | * whether the option is enabled or disabled. The socket option is specific to | ||
| 336 | * stream-oriented sockets using the TCP/IP protocol. TCP/IP uses an algorithm | ||
| 337 | * known as <em>The Nagle Algorithm</em> to coalesce short segments and | ||
| 338 | * improve network efficiency. | ||
| 339 | * | ||
| 340 | * <p> The default value of this socket option is {@code FALSE}. The | ||
| 341 | * socket option should only be enabled in cases where it is known that the | ||
| 342 | * coalescing impacts performance. The socket option may be enabled at any | ||
| 343 | * time. In other words, the Nagle Algorithm can be disabled. Once the option | ||
| 344 | * is enabled, it is system dependent whether it can be subsequently | ||
| 345 | * disabled. If it cannot, then invoking the {@code setOption} method to | ||
| 346 | * disable the option has no effect. | ||
| 347 | * | ||
| 348 | * @see <a href="http://www.ietf.org/rfc/rfc1122.txt">RFC 1122: | ||
| 349 | * Requirements for Internet Hosts -- Communication Layers</a> | ||
| 350 | * @see Socket#setTcpNoDelay | ||
| 351 | */ | ||
| 352 | public static final SocketOption<Boolean> TCP_NODELAY = | ||
| 353 | new StdSocketOption<Boolean>("TCP_NODELAY", Boolean.class); | ||
| 354 | |||
| 355 | |||
| 356 | private static class StdSocketOption<T> implements SocketOption<T> { | ||
| 357 | private final String name; | ||
| 358 | private final Class<T> type; | ||
| 359 | StdSocketOption(String name, Class<T> type) { | ||
| 360 | this.name = name; | ||
| 361 | this.type = type; | ||
| 362 | } | ||
| 363 | @Override public String name() { return name; } | ||
| 364 | @Override public Class<T> type() { return type; } | ||
| 365 | @Override public String toString() { return name; } | ||
| 366 | } | ||
| 367 | } | ||