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| 1 | +/* | |
| 2 | + * Copyright (c) 1996, 2006, 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 | + * Interface of methods to get/set socket options. This interface is | |
| 30 | + * implemented by: <B>SocketImpl</B> and <B>DatagramSocketImpl</B>. | |
| 31 | + * Subclasses of these should override the methods | |
| 32 | + * of this interface in order to support their own options. | |
| 33 | + * <P> | |
| 34 | + * The methods and constants which specify options in this interface are | |
| 35 | + * for implementation only. If you're not subclassing SocketImpl or | |
| 36 | + * DatagramSocketImpl, <B>you won't use these directly.</B> There are | |
| 37 | + * type-safe methods to get/set each of these options in Socket, ServerSocket, | |
| 38 | + * DatagramSocket and MulticastSocket. | |
| 39 | + * <P> | |
| 40 | + * @author David Brown | |
| 41 | + */ | |
| 42 | + | |
| 43 | + | |
| 44 | +public interface SocketOptions { | |
| 45 | + | |
| 46 | + /** | |
| 47 | + * Enable/disable the option specified by <I>optID</I>. If the option | |
| 48 | + * is to be enabled, and it takes an option-specific "value", this is | |
| 49 | + * passed in <I>value</I>. The actual type of value is option-specific, | |
| 50 | + * and it is an error to pass something that isn't of the expected type: | |
| 51 | + * <BR><PRE> | |
| 52 | + * SocketImpl s; | |
| 53 | + * ... | |
| 54 | + * s.setOption(SO_LINGER, new Integer(10)); | |
| 55 | + * // OK - set SO_LINGER w/ timeout of 10 sec. | |
| 56 | + * s.setOption(SO_LINGER, new Double(10)); | |
| 57 | + * // ERROR - expects java.lang.Integer | |
| 58 | + *</PRE> | |
| 59 | + * If the requested option is binary, it can be set using this method by | |
| 60 | + * a java.lang.Boolean: | |
| 61 | + * <BR><PRE> | |
| 62 | + * s.setOption(TCP_NODELAY, new Boolean(true)); | |
| 63 | + * // OK - enables TCP_NODELAY, a binary option | |
| 64 | + * </PRE> | |
| 65 | + * <BR> | |
| 66 | + * Any option can be disabled using this method with a Boolean(false): | |
| 67 | + * <BR><PRE> | |
| 68 | + * s.setOption(TCP_NODELAY, new Boolean(false)); | |
| 69 | + * // OK - disables TCP_NODELAY | |
| 70 | + * s.setOption(SO_LINGER, new Boolean(false)); | |
| 71 | + * // OK - disables SO_LINGER | |
| 72 | + * </PRE> | |
| 73 | + * <BR> | |
| 74 | + * For an option that has a notion of on and off, and requires | |
| 75 | + * a non-boolean parameter, setting its value to anything other than | |
| 76 | + * <I>Boolean(false)</I> implicitly enables it. | |
| 77 | + * <BR> | |
| 78 | + * Throws SocketException if the option is unrecognized, | |
| 79 | + * the socket is closed, or some low-level error occurred | |
| 80 | + * <BR> | |
| 81 | + * @param optID identifies the option | |
| 82 | + * @param value the parameter of the socket option | |
| 83 | + * @throws SocketException if the option is unrecognized, | |
| 84 | + * the socket is closed, or some low-level error occurred | |
| 85 | + * @see #getOption(int) | |
| 86 | + */ | |
| 87 | + public void | |
| 88 | + setOption(int optID, Object value) throws SocketException; | |
| 89 | + | |
| 90 | + /** | |
| 91 | + * Fetch the value of an option. | |
| 92 | + * Binary options will return java.lang.Boolean(true) | |
| 93 | + * if enabled, java.lang.Boolean(false) if disabled, e.g.: | |
| 94 | + * <BR><PRE> | |
| 95 | + * SocketImpl s; | |
| 96 | + * ... | |
| 97 | + * Boolean noDelay = (Boolean)(s.getOption(TCP_NODELAY)); | |
| 98 | + * if (noDelay.booleanValue()) { | |
| 99 | + * // true if TCP_NODELAY is enabled... | |
| 100 | + * ... | |
| 101 | + * } | |
| 102 | + * </PRE> | |
| 103 | + * <P> | |
| 104 | + * For options that take a particular type as a parameter, | |
| 105 | + * getOption(int) will return the parameter's value, else | |
| 106 | + * it will return java.lang.Boolean(false): | |
| 107 | + * <PRE> | |
| 108 | + * Object o = s.getOption(SO_LINGER); | |
| 109 | + * if (o instanceof Integer) { | |
| 110 | + * System.out.print("Linger time is " + ((Integer)o).intValue()); | |
| 111 | + * } else { | |
| 112 | + * // the true type of o is java.lang.Boolean(false); | |
| 113 | + * } | |
| 114 | + * </PRE> | |
| 115 | + * | |
| 116 | + * @param optID an <code>int</code> identifying the option to fetch | |
| 117 | + * @return the value of the option | |
| 118 | + * @throws SocketException if the socket is closed | |
| 119 | + * @throws SocketException if <I>optID</I> is unknown along the | |
| 120 | + * protocol stack (including the SocketImpl) | |
| 121 | + * @see #setOption(int, java.lang.Object) | |
| 122 | + */ | |
| 123 | + public Object getOption(int optID) throws SocketException; | |
| 124 | + | |
| 125 | + /** | |
| 126 | + * The java-supported BSD-style options. | |
| 127 | + */ | |
| 128 | + | |
| 129 | + /** | |
| 130 | + * Disable Nagle's algorithm for this connection. Written data | |
| 131 | + * to the network is not buffered pending acknowledgement of | |
| 132 | + * previously written data. | |
| 133 | + *<P> | |
| 134 | + * Valid for TCP only: SocketImpl. | |
| 135 | + * <P> | |
| 136 | + * @see Socket#setTcpNoDelay | |
| 137 | + * @see Socket#getTcpNoDelay | |
| 138 | + */ | |
| 139 | + | |
| 140 | + public final static int TCP_NODELAY = 0x0001; | |
| 141 | + | |
| 142 | + /** | |
| 143 | + * Fetch the local address binding of a socket (this option cannot | |
| 144 | + * be "set" only "gotten", since sockets are bound at creation time, | |
| 145 | + * and so the locally bound address cannot be changed). The default local | |
| 146 | + * address of a socket is INADDR_ANY, meaning any local address on a | |
| 147 | + * multi-homed host. A multi-homed host can use this option to accept | |
| 148 | + * connections to only one of its addresses (in the case of a | |
| 149 | + * ServerSocket or DatagramSocket), or to specify its return address | |
| 150 | + * to the peer (for a Socket or DatagramSocket). The parameter of | |
| 151 | + * this option is an InetAddress. | |
| 152 | + * <P> | |
| 153 | + * This option <B>must</B> be specified in the constructor. | |
| 154 | + * <P> | |
| 155 | + * Valid for: SocketImpl, DatagramSocketImpl | |
| 156 | + * <P> | |
| 157 | + * @see Socket#getLocalAddress | |
| 158 | + * @see DatagramSocket#getLocalAddress | |
| 159 | + */ | |
| 160 | + | |
| 161 | + public final static int SO_BINDADDR = 0x000F; | |
| 162 | + | |
| 163 | + /** Sets SO_REUSEADDR for a socket. This is used only for MulticastSockets | |
| 164 | + * in java, and it is set by default for MulticastSockets. | |
| 165 | + * <P> | |
| 166 | + * Valid for: DatagramSocketImpl | |
| 167 | + */ | |
| 168 | + | |
| 169 | + public final static int SO_REUSEADDR = 0x04; | |
| 170 | + | |
| 171 | + /** | |
| 172 | + * Sets SO_BROADCAST for a socket. This option enables and disables | |
| 173 | + * the ability of the process to send broadcast messages. It is supported | |
| 174 | + * for only datagram sockets and only on networks that support | |
| 175 | + * the concept of a broadcast message (e.g. Ethernet, token ring, etc.), | |
| 176 | + * and it is set by default for DatagramSockets. | |
| 177 | + * @since 1.4 | |
| 178 | + */ | |
| 179 | + | |
| 180 | + public final static int SO_BROADCAST = 0x0020; | |
| 181 | + | |
| 182 | + /** Set which outgoing interface on which to send multicast packets. | |
| 183 | + * Useful on hosts with multiple network interfaces, where applications | |
| 184 | + * want to use other than the system default. Takes/returns an InetAddress. | |
| 185 | + * <P> | |
| 186 | + * Valid for Multicast: DatagramSocketImpl | |
| 187 | + * <P> | |
| 188 | + * @see MulticastSocket#setInterface(InetAddress) | |
| 189 | + * @see MulticastSocket#getInterface() | |
| 190 | + */ | |
| 191 | + | |
| 192 | + public final static int IP_MULTICAST_IF = 0x10; | |
| 193 | + | |
| 194 | + /** Same as above. This option is introduced so that the behaviour | |
| 195 | + * with IP_MULTICAST_IF will be kept the same as before, while | |
| 196 | + * this new option can support setting outgoing interfaces with either | |
| 197 | + * IPv4 and IPv6 addresses. | |
| 198 | + * | |
| 199 | + * NOTE: make sure there is no conflict with this | |
| 200 | + * @see MulticastSocket#setNetworkInterface(NetworkInterface) | |
| 201 | + * @see MulticastSocket#getNetworkInterface() | |
| 202 | + * @since 1.4 | |
| 203 | + */ | |
| 204 | + public final static int IP_MULTICAST_IF2 = 0x1f; | |
| 205 | + | |
| 206 | + /** | |
| 207 | + * This option enables or disables local loopback of multicast datagrams. | |
| 208 | + * This option is enabled by default for Multicast Sockets. | |
| 209 | + * @since 1.4 | |
| 210 | + */ | |
| 211 | + | |
| 212 | + public final static int IP_MULTICAST_LOOP = 0x12; | |
| 213 | + | |
| 214 | + /** | |
| 215 | + * This option sets the type-of-service or traffic class field | |
| 216 | + * in the IP header for a TCP or UDP socket. | |
| 217 | + * @since 1.4 | |
| 218 | + */ | |
| 219 | + | |
| 220 | + public final static int IP_TOS = 0x3; | |
| 221 | + | |
| 222 | + /** | |
| 223 | + * Specify a linger-on-close timeout. This option disables/enables | |
| 224 | + * immediate return from a <B>close()</B> of a TCP Socket. Enabling | |
| 225 | + * this option with a non-zero Integer <I>timeout</I> means that a | |
| 226 | + * <B>close()</B> will block pending the transmission and acknowledgement | |
| 227 | + * of all data written to the peer, at which point the socket is closed | |
| 228 | + * <I>gracefully</I>. Upon reaching the linger timeout, the socket is | |
| 229 | + * closed <I>forcefully</I>, with a TCP RST. Enabling the option with a | |
| 230 | + * timeout of zero does a forceful close immediately. If the specified | |
| 231 | + * timeout value exceeds 65,535 it will be reduced to 65,535. | |
| 232 | + * <P> | |
| 233 | + * Valid only for TCP: SocketImpl | |
| 234 | + * | |
| 235 | + * @see Socket#setSoLinger | |
| 236 | + * @see Socket#getSoLinger | |
| 237 | + */ | |
| 238 | + public final static int SO_LINGER = 0x0080; | |
| 239 | + | |
| 240 | + /** Set a timeout on blocking Socket operations: | |
| 241 | + * <PRE> | |
| 242 | + * ServerSocket.accept(); | |
| 243 | + * SocketInputStream.read(); | |
| 244 | + * DatagramSocket.receive(); | |
| 245 | + * </PRE> | |
| 246 | + * | |
| 247 | + * <P> The option must be set prior to entering a blocking | |
| 248 | + * operation to take effect. If the timeout expires and the | |
| 249 | + * operation would continue to block, | |
| 250 | + * <B>java.io.InterruptedIOException</B> is raised. The Socket is | |
| 251 | + * not closed in this case. | |
| 252 | + * | |
| 253 | + * <P> Valid for all sockets: SocketImpl, DatagramSocketImpl | |
| 254 | + * | |
| 255 | + * @see Socket#setSoTimeout | |
| 256 | + * @see ServerSocket#setSoTimeout | |
| 257 | + * @see DatagramSocket#setSoTimeout | |
| 258 | + */ | |
| 259 | + public final static int SO_TIMEOUT = 0x1006; | |
| 260 | + | |
| 261 | + /** | |
| 262 | + * Set a hint the size of the underlying buffers used by the | |
| 263 | + * platform for outgoing network I/O. When used in set, this is a | |
| 264 | + * suggestion to the kernel from the application about the size of | |
| 265 | + * buffers to use for the data to be sent over the socket. When | |
| 266 | + * used in get, this must return the size of the buffer actually | |
| 267 | + * used by the platform when sending out data on this socket. | |
| 268 | + * | |
| 269 | + * Valid for all sockets: SocketImpl, DatagramSocketImpl | |
| 270 | + * | |
| 271 | + * @see Socket#setSendBufferSize | |
| 272 | + * @see Socket#getSendBufferSize | |
| 273 | + * @see DatagramSocket#setSendBufferSize | |
| 274 | + * @see DatagramSocket#getSendBufferSize | |
| 275 | + */ | |
| 276 | + public final static int SO_SNDBUF = 0x1001; | |
| 277 | + | |
| 278 | + /** | |
| 279 | + * Set a hint the size of the underlying buffers used by the | |
| 280 | + * platform for incoming network I/O. When used in set, this is a | |
| 281 | + * suggestion to the kernel from the application about the size of | |
| 282 | + * buffers to use for the data to be received over the | |
| 283 | + * socket. When used in get, this must return the size of the | |
| 284 | + * buffer actually used by the platform when receiving in data on | |
| 285 | + * this socket. | |
| 286 | + * | |
| 287 | + * Valid for all sockets: SocketImpl, DatagramSocketImpl | |
| 288 | + * | |
| 289 | + * @see Socket#setReceiveBufferSize | |
| 290 | + * @see Socket#getReceiveBufferSize | |
| 291 | + * @see DatagramSocket#setReceiveBufferSize | |
| 292 | + * @see DatagramSocket#getReceiveBufferSize | |
| 293 | + */ | |
| 294 | + public final static int SO_RCVBUF = 0x1002; | |
| 295 | + | |
| 296 | + /** | |
| 297 | + * When the keepalive option is set for a TCP socket and no data | |
| 298 | + * has been exchanged across the socket in either direction for | |
| 299 | + * 2 hours (NOTE: the actual value is implementation dependent), | |
| 300 | + * TCP automatically sends a keepalive probe to the peer. This probe is a | |
| 301 | + * TCP segment to which the peer must respond. | |
| 302 | + * One of three responses is expected: | |
| 303 | + * 1. The peer responds with the expected ACK. The application is not | |
| 304 | + * notified (since everything is OK). TCP will send another probe | |
| 305 | + * following another 2 hours of inactivity. | |
| 306 | + * 2. The peer responds with an RST, which tells the local TCP that | |
| 307 | + * the peer host has crashed and rebooted. The socket is closed. | |
| 308 | + * 3. There is no response from the peer. The socket is closed. | |
| 309 | + * | |
| 310 | + * The purpose of this option is to detect if the peer host crashes. | |
| 311 | + * | |
| 312 | + * Valid only for TCP socket: SocketImpl | |
| 313 | + * | |
| 314 | + * @see Socket#setKeepAlive | |
| 315 | + * @see Socket#getKeepAlive | |
| 316 | + */ | |
| 317 | + public final static int SO_KEEPALIVE = 0x0008; | |
| 318 | + | |
| 319 | + /** | |
| 320 | + * When the OOBINLINE option is set, any TCP urgent data received on | |
| 321 | + * the socket will be received through the socket input stream. | |
| 322 | + * When the option is disabled (which is the default) urgent data | |
| 323 | + * is silently discarded. | |
| 324 | + * | |
| 325 | + * @see Socket#setOOBInline | |
| 326 | + * @see Socket#getOOBInline | |
| 327 | + */ | |
| 328 | + public final static int SO_OOBINLINE = 0x1003; | |
| 329 | +} | |