Inet4Address.java 12.9 KB
Newer Older
D
duke 已提交
1
/*
2
 * Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
D
duke 已提交
3 4 5 6
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
7
 * published by the Free Software Foundation.  Oracle designates this
D
duke 已提交
8
 * particular file as subject to the "Classpath" exception as provided
9
 * by Oracle in the LICENSE file that accompanied this code.
D
duke 已提交
10 11 12 13 14 15 16 17 18 19 20
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
21 22 23
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
D
duke 已提交
24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372
 */

package java.net;

import java.io.ObjectStreamException;

/**
 * This class represents an Internet Protocol version 4 (IPv4) address.
 * Defined by <a href="http://www.ietf.org/rfc/rfc790.txt">
 * <i>RFC&nbsp;790: Assigned Numbers</i></a>,
 * <a href="http://www.ietf.org/rfc/rfc1918.txt">
 * <i>RFC&nbsp;1918: Address Allocation for Private Internets</i></a>,
 * and <a href="http://www.ietf.org/rfc/rfc2365.txt"><i>RFC&nbsp;2365:
 * Administratively Scoped IP Multicast</i></a>
 *
 * <h4> <A NAME="format">Textual representation of IP addresses</a> </h4>
 *
 * Textual representation of IPv4 address used as input to methods
 * takes one of the following forms:
 *
 * <blockquote><table cellpadding=0 cellspacing=0 summary="layout">
 * <tr><td><tt>d.d.d.d</tt></td></tr>
 * <tr><td><tt>d.d.d</tt></td></tr>
 * <tr><td><tt>d.d</tt></td></tr>
 * <tr><td><tt>d</tt></td></tr>
 * </table></blockquote>
 *
 * <p> When four parts are specified, each is interpreted as a byte of
 * data and assigned, from left to right, to the four bytes of an IPv4
 * address.

 * <p> When a three part address is specified, the last part is
 * interpreted as a 16-bit quantity and placed in the right most two
 * bytes of the network address. This makes the three part address
 * format convenient for specifying Class B net- work addresses as
 * 128.net.host.
 *
 * <p> When a two part address is supplied, the last part is
 * interpreted as a 24-bit quantity and placed in the right most three
 * bytes of the network address. This makes the two part address
 * format convenient for specifying Class A network addresses as
 * net.host.
 *
 * <p> When only one part is given, the value is stored directly in
 * the network address without any byte rearrangement.
 *
 * <p> For methods that return a textual representation as output
 * value, the first form, i.e. a dotted-quad string, is used.
 *
 * <h4> The Scope of a Multicast Address </h4>
 *
 * Historically the IPv4 TTL field in the IP header has doubled as a
 * multicast scope field: a TTL of 0 means node-local, 1 means
 * link-local, up through 32 means site-local, up through 64 means
 * region-local, up through 128 means continent-local, and up through
 * 255 are global. However, the administrative scoping is preferred.
 * Please refer to <a href="http://www.ietf.org/rfc/rfc2365.txt">
 * <i>RFC&nbsp;2365: Administratively Scoped IP Multicast</i></a>
 * @since 1.4
 */

public final
class Inet4Address extends InetAddress {
    final static int INADDRSZ = 4;

    /** use serialVersionUID from InetAddress, but Inet4Address instance
     *  is always replaced by an InetAddress instance before being
     *  serialized */
    private static final long serialVersionUID = 3286316764910316507L;

    /*
     * Perform initializations.
     */
    static {
        init();
    }

    Inet4Address() {
        super();
        hostName = null;
        address = 0;
        family = IPv4;
    }

    Inet4Address(String hostName, byte addr[]) {
        this.hostName = hostName;
        this.family = IPv4;
        if (addr != null) {
            if (addr.length == INADDRSZ) {
                address  = addr[3] & 0xFF;
                address |= ((addr[2] << 8) & 0xFF00);
                address |= ((addr[1] << 16) & 0xFF0000);
                address |= ((addr[0] << 24) & 0xFF000000);
            }
        }
    }
    Inet4Address(String hostName, int address) {
        this.hostName = hostName;
        this.family = IPv4;
        this.address = address;
    }

    /**
     * Replaces the object to be serialized with an InetAddress object.
     *
     * @return the alternate object to be serialized.
     *
     * @throws ObjectStreamException if a new object replacing this
     * object could not be created
     */
    private Object writeReplace() throws ObjectStreamException {
        // will replace the to be serialized 'this' object
        InetAddress inet = new InetAddress();
        inet.hostName = this.hostName;
        inet.address = this.address;

        /**
         * Prior to 1.4 an InetAddress was created with a family
         * based on the platform AF_INET value (usually 2).
         * For compatibility reasons we must therefore write the
         * the InetAddress with this family.
         */
        inet.family = 2;

        return inet;
    }

    /**
     * Utility routine to check if the InetAddress is an
     * IP multicast address. IP multicast address is a Class D
     * address i.e first four bits of the address are 1110.
     * @return a <code>boolean</code> indicating if the InetAddress is
     * an IP multicast address
     * @since   JDK1.1
     */
    public boolean isMulticastAddress() {
        return ((address & 0xf0000000) == 0xe0000000);
    }

    /**
     * Utility routine to check if the InetAddress in a wildcard address.
     * @return a <code>boolean</code> indicating if the Inetaddress is
     *         a wildcard address.
     * @since 1.4
     */
    public boolean isAnyLocalAddress() {
        return address == 0;
    }

    /**
     * Utility routine to check if the InetAddress is a loopback address.
     *
     * @return a <code>boolean</code> indicating if the InetAddress is
     * a loopback address; or false otherwise.
     * @since 1.4
     */
    private static final int loopback = 2130706433; /* 127.0.0.1 */
    public boolean isLoopbackAddress() {
        /* 127.x.x.x */
        byte[] byteAddr = getAddress();
        return byteAddr[0] == 127;
    }

    /**
     * Utility routine to check if the InetAddress is an link local address.
     *
     * @return a <code>boolean</code> indicating if the InetAddress is
     * a link local address; or false if address is not a link local unicast address.
     * @since 1.4
     */
    public boolean isLinkLocalAddress() {
        // link-local unicast in IPv4 (169.254.0.0/16)
        // defined in "Documenting Special Use IPv4 Address Blocks
        // that have been Registered with IANA" by Bill Manning
        // draft-manning-dsua-06.txt
        return (((address >>> 24) & 0xFF) == 169)
            && (((address >>> 16) & 0xFF) == 254);
    }

    /**
     * Utility routine to check if the InetAddress is a site local address.
     *
     * @return a <code>boolean</code> indicating if the InetAddress is
     * a site local address; or false if address is not a site local unicast address.
     * @since 1.4
     */
    public boolean isSiteLocalAddress() {
        // refer to RFC 1918
        // 10/8 prefix
        // 172.16/12 prefix
        // 192.168/16 prefix
        return (((address >>> 24) & 0xFF) == 10)
            || ((((address >>> 24) & 0xFF) == 172)
                && (((address >>> 16) & 0xF0) == 16))
            || ((((address >>> 24) & 0xFF) == 192)
                && (((address >>> 16) & 0xFF) == 168));
    }

    /**
     * Utility routine to check if the multicast address has global scope.
     *
     * @return a <code>boolean</code> indicating if the address has
     *         is a multicast address of global scope, false if it is not
     *         of global scope or it is not a multicast address
     * @since 1.4
     */
    public boolean isMCGlobal() {
        // 224.0.1.0 to 238.255.255.255
        byte[] byteAddr = getAddress();
        return ((byteAddr[0] & 0xff) >= 224 && (byteAddr[0] & 0xff) <= 238 ) &&
            !((byteAddr[0] & 0xff) == 224 && byteAddr[1] == 0 &&
              byteAddr[2] == 0);
    }

    /**
     * Utility routine to check if the multicast address has node scope.
     *
     * @return a <code>boolean</code> indicating if the address has
     *         is a multicast address of node-local scope, false if it is not
     *         of node-local scope or it is not a multicast address
     * @since 1.4
     */
    public boolean isMCNodeLocal() {
        // unless ttl == 0
        return false;
    }

    /**
     * Utility routine to check if the multicast address has link scope.
     *
     * @return a <code>boolean</code> indicating if the address has
     *         is a multicast address of link-local scope, false if it is not
     *         of link-local scope or it is not a multicast address
     * @since 1.4
     */
    public boolean isMCLinkLocal() {
        // 224.0.0/24 prefix and ttl == 1
        return (((address >>> 24) & 0xFF) == 224)
            && (((address >>> 16) & 0xFF) == 0)
            && (((address >>> 8) & 0xFF) == 0);
    }

    /**
     * Utility routine to check if the multicast address has site scope.
     *
     * @return a <code>boolean</code> indicating if the address has
     *         is a multicast address of site-local scope, false if it is not
     *         of site-local scope or it is not a multicast address
     * @since 1.4
     */
    public boolean isMCSiteLocal() {
        // 239.255/16 prefix or ttl < 32
        return (((address >>> 24) & 0xFF) == 239)
            && (((address >>> 16) & 0xFF) == 255);
    }

    /**
     * Utility routine to check if the multicast address has organization scope.
     *
     * @return a <code>boolean</code> indicating if the address has
     *         is a multicast address of organization-local scope,
     *         false if it is not of organization-local scope
     *         or it is not a multicast address
     * @since 1.4
     */
    public boolean isMCOrgLocal() {
        // 239.192 - 239.195
        return (((address >>> 24) & 0xFF) == 239)
            && (((address >>> 16) & 0xFF) >= 192)
            && (((address >>> 16) & 0xFF) <= 195);
    }

    /**
     * Returns the raw IP address of this <code>InetAddress</code>
     * object. The result is in network byte order: the highest order
     * byte of the address is in <code>getAddress()[0]</code>.
     *
     * @return  the raw IP address of this object.
     */
    public byte[] getAddress() {
        byte[] addr = new byte[INADDRSZ];

        addr[0] = (byte) ((address >>> 24) & 0xFF);
        addr[1] = (byte) ((address >>> 16) & 0xFF);
        addr[2] = (byte) ((address >>> 8) & 0xFF);
        addr[3] = (byte) (address & 0xFF);
        return addr;
    }

    /**
     * Returns the IP address string in textual presentation form.
     *
     * @return  the raw IP address in a string format.
     * @since   JDK1.0.2
     */
    public String getHostAddress() {
        return numericToTextFormat(getAddress());
    }

    /**
     * Returns a hashcode for this IP address.
     *
     * @return  a hash code value for this IP address.
     */
    public int hashCode() {
        return address;
    }

    /**
     * Compares this object against the specified object.
     * The result is <code>true</code> if and only if the argument is
     * not <code>null</code> and it represents the same IP address as
     * this object.
     * <p>
     * Two instances of <code>InetAddress</code> represent the same IP
     * address if the length of the byte arrays returned by
     * <code>getAddress</code> is the same for both, and each of the
     * array components is the same for the byte arrays.
     *
     * @param   obj   the object to compare against.
     * @return  <code>true</code> if the objects are the same;
     *          <code>false</code> otherwise.
     * @see     java.net.InetAddress#getAddress()
     */
    public boolean equals(Object obj) {
        return (obj != null) && (obj instanceof Inet4Address) &&
            (((InetAddress)obj).address == address);
    }

    // Utilities
    /*
     * Converts IPv4 binary address into a string suitable for presentation.
     *
     * @param src a byte array representing an IPv4 numeric address
     * @return a String representing the IPv4 address in
     *         textual representation format
     * @since 1.4
     */

    static String numericToTextFormat(byte[] src)
    {
        return (src[0] & 0xff) + "." + (src[1] & 0xff) + "." + (src[2] & 0xff) + "." + (src[3] & 0xff);
    }

    /**
     * Perform class load-time initializations.
     */
    private static native void init();
}