/*
 * @(#)Inet4Address.java	1.24 03/01/23
 *
 * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package java.net;

import java.security.AccessController;
import java.io.ObjectStreamException;
import sun.security.action.*;

/**
 * This class represents an Internet Protocol version 4 (IPv4) address.
 * Defined by <a href="http://www.ietf.org/rfc/rfc790.txt">
 * <i>RFC 790: Assigned Numbers</i></a>,
 * <a href="http://www.ietf.org/rfc/rfc1918.txt">
 * <i>RFC 1918: Address Allocation for Private Internets</i></a>,
 * and <a href="http://www.ietf.org/rfc/rfc2365.txt"><i>RFC 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</td></tr>
 * <tr><td><tt>d</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 2365: Administratively Scoped IP Multicast</i></a>
 */

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);
    }

    /*
     * Converts IPv4 address in its textual presentation form 
     * into its numeric binary form.
     * 
     * @param src a String representing an IPv4 address in standard format
     * @return a byte array representing the IPv4 numeric address
     * @since 1.4
     */
    static byte[] textToNumericFormat(String src)
    {
	if (src.length() == 0) {
	    return null;
	}
	
	int octets;
	char ch;
	byte[] dst = new byte[INADDRSZ];
        char[] srcb = src.toCharArray();
	boolean saw_digit = false;

	octets = 0;
	int i = 0;
	int cur = 0;
	while (i < srcb.length) {
	    ch = srcb[i++];
	    if (Character.isDigit(ch)) {
		// note that Java byte is signed, so need to convert to int
		int sum = (dst[cur] & 0xff)*10
		    + (Character.digit(ch, 10) & 0xff);
		
		if (sum > 255)
		    return null;

		dst[cur] = (byte)(sum & 0xff);
		if (! saw_digit) {
		    if (++octets > INADDRSZ)
			return null;
		    saw_digit = true;
		}
	    } else if (ch == '.' && saw_digit) {
		if (octets == INADDRSZ)
		    return null;
		cur++;
		dst[cur] = 0;
		saw_digit = false;
	    } else
		return null;
	}
	if (octets < INADDRSZ)
	    return null;
	return dst;
    }
    
    /**
     * Perform class load-time initializations.
     */
    private static native void init();
}