/*

 * Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.

 * 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

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * 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.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

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>

 *

 * <h2> <a id="format">Textual representation of IP addresses</a> </h2>

 *

 * Textual representation of IPv4 address used as input to methods

 * takes one of the following forms:

 *

 * <blockquote><ul style="list-style-type:none">

 * <li>{@code d.d.d.d}</li>

 * <li>{@code d.d.d}</li>

 * <li>{@code d.d}</li>

 * <li>{@code d}</li>

 * </ul></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.

 *

 * <h3> The Scope of a Multicast Address </h3>

 *

 * 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 {

    static final int INADDRSZ = 4;

    /** use serialVersionUID from InetAddress, but Inet4Address instance

     *  is always replaced by an InetAddress instance before being

     *  serialized */

    @java.io.Serial

    private static final long serialVersionUID = 3286316764910316507L;

    /*

     * Perform initializations.

     */

    static {

        init();

    }

    Inet4Address() {

        super();

        holder().hostName = null;

        holder().address = 0;

        holder().family = IPv4;

    }

    Inet4Address(String hostName, byte addr[]) {

        holder().hostName = hostName;

        holder().family = IPv4;

        if (addr != null) {

            if (addr.length == INADDRSZ) {

                int address  = addr[3] & 0xFF;

                address |= ((addr[2] << 8) & 0xFF00);

                address |= ((addr[1] << 16) & 0xFF0000);

                address |= ((addr[0] << 24) & 0xFF000000);

                holder().address = address;

            }

        }

        holder().originalHostName = hostName;

    }

    Inet4Address(String hostName, int address) {

        holder().hostName = hostName;

        holder().family = IPv4;

        holder().address = address;

        holder().originalHostName = hostName;

    }

    /**

     * 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

     */

    @java.io.Serial

    private Object writeReplace() throws ObjectStreamException {

        // will replace the to be serialized 'this' object

        InetAddress inet = new InetAddress();

        inet.holder().hostName = holder().getHostName();

        inet.holder().address = holder().getAddress();

        /**

         * 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 InetAddress with this family.

         */

        inet.holder().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} indicating if the InetAddress is

     * an IP multicast address

     */

    public boolean isMulticastAddress() {

        return ((holder().getAddress() & 0xf0000000) == 0xe0000000);

    }

    /**

     * Utility routine to check if the InetAddress is a wildcard address.

     * @return a {@code boolean} indicating if the InetAddress is

     *         a wildcard address.

     */

    public boolean isAnyLocalAddress() {

        return holder().getAddress() == 0;

    }

    /**

     * Utility routine to check if the InetAddress is a loopback address.

     *

     * @return a {@code boolean} indicating if the InetAddress is

     * a loopback address; or false otherwise.

     */

    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} indicating if the InetAddress is

     * a link local address; or false if address is not a link local unicast address.

     */

    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

        int address = holder().getAddress();

        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} indicating if the InetAddress is

     * a site local address; or false if address is not a site local unicast address.

     */

    public boolean isSiteLocalAddress() {

        // refer to RFC 1918

        // 10/8 prefix

        // 172.16/12 prefix

        // 192.168/16 prefix

        int address = holder().getAddress();

        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} 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

     */

    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} 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

     */

    public boolean isMCNodeLocal() {

        // unless ttl == 0

        return false;

    }

    /**

     * Utility routine to check if the multicast address has link scope.

     *

     * @return a {@code boolean} 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

     */

    public boolean isMCLinkLocal() {

        // 224.0.0/24 prefix and ttl == 1

        int address = holder().getAddress();

        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} 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

     */

    public boolean isMCSiteLocal() {

        // 239.255/16 prefix or ttl < 32

        int address = holder().getAddress();

        return (((address >>> 24) & 0xFF) == 239)

            && (((address >>> 16) & 0xFF) == 255);

    }

    /**

     * Utility routine to check if the multicast address has organization scope.

     *

     * @return a {@code boolean} 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

     */

    public boolean isMCOrgLocal() {

        // 239.192 - 239.195

        int address = holder().getAddress();

        return (((address >>> 24) & 0xFF) == 239)

            && (((address >>> 16) & 0xFF) >= 192)

            && (((address >>> 16) & 0xFF) <= 195);

    }

    /**

     * Returns the raw IP address of this {@code InetAddress}

     * object. The result is in network byte order: the highest order

     * byte of the address is in {@code getAddress()[0]}.

     *

     * @return  the raw IP address of this object.

     */

    public byte[] getAddress() {

        int address = holder().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.

     */

    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 holder().getAddress();

    }

    /**

     * Compares this object against the specified object.

     * The result is {@code true} if and only if the argument is

     * not {@code null} and it represents the same IP address as

     * this object.

     * <p>

     * Two instances of {@code InetAddress} represent the same IP

     * address if the length of the byte arrays returned by

     * {@code getAddress} 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} if the objects are the same;

     *          {@code false} otherwise.

     * @see     java.net.InetAddress#getAddress()

     */

    public boolean equals(Object obj) {

        return (obj != null) && (obj instanceof Inet4Address) &&

            (((InetAddress)obj).holder().getAddress() == holder().getAddress());

    }

    // 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

     */

    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();

}