/*

 * 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/*

 *

 *  (C) Copyright IBM Corp. 1999 All Rights Reserved.

 *  Copyright 1997 The Open Group Research Institute.  All rights reserved.

 */

package sun.security.krb5.internal;

import sun.security.krb5.Config;

import sun.security.krb5.Asn1Exception;

import sun.security.util.*;

import java.net.InetAddress;

import java.net.Inet4Address;

import java.net.Inet6Address;

import java.net.UnknownHostException;

import java.io.IOException;

import java.util.Arrays;

/**

 * Implements the ASN.1 HostAddress type.

 *

 * <pre>{@code

 * HostAddress     ::= SEQUENCE  {

 *         addr-type       [0] Int32,

 *         address         [1] OCTET STRING

 * }

 * }</pre>

 *

 * <p>

 * This definition reflects the Network Working Group RFC 4120

 * specification available at

 * <a href="http://www.ietf.org/rfc/rfc4120.txt">

 * http://www.ietf.org/rfc/rfc4120.txt</a>.

 */

public class HostAddress implements Cloneable {

    int addrType;

    byte[] address = null;

    private static InetAddress localInetAddress; //caches local inet address

    private static final boolean DEBUG = sun.security.krb5.internal.Krb5.DEBUG;

    private volatile int hashCode = 0;

    private HostAddress(int dummy) {}

    public Object clone() {

        HostAddress new_hostAddress = new HostAddress(0);

        new_hostAddress.addrType = addrType;

        if (address != null) {

            new_hostAddress.address = address.clone();

        }

        return new_hostAddress;

    }

    public int hashCode() {

        if (hashCode == 0) {

            int result = 17;

            result = 37*result + addrType;

            if (address != null) {

                for (int i=0; i < address.length; i++)  {

                    result = 37*result + address[i];

                }

            }

            hashCode = result;

        }

        return hashCode;

    }

    public boolean equals(Object obj) {

        if (this == obj) {

            return true;

        }

        if (!(obj instanceof HostAddress)) {

            return false;

        }

        HostAddress h = (HostAddress)obj;

        if (addrType != h.addrType ||

            (address != null && h.address == null) ||

            (address == null && h.address != null))

            return false;

        if (address != null && h.address != null) {

            if (address.length != h.address.length)

                return false;

            for (int i = 0; i < address.length; i++)

                if (address[i] != h.address[i])

                    return false;

        }

        return true;

    }

    private static synchronized InetAddress getLocalInetAddress()

        throws UnknownHostException {

        if (localInetAddress == null) {

           localInetAddress = InetAddress.getLocalHost();

        }

        if (localInetAddress == null) {

            throw new UnknownHostException();

        }

        return (localInetAddress);

    }

    /**

     * Gets the InetAddress of this HostAddress.

     * @return the IP address for this specified host.

     * @exception UnknownHostException if no IP address for the host could be found.

     *

     */

    public InetAddress getInetAddress() throws UnknownHostException {

        // the type of internet addresses is 2.

        if (addrType == Krb5.ADDRTYPE_INET ||

            addrType == Krb5.ADDRTYPE_INET6) {

            return (InetAddress.getByAddress(address));

        } else {

            // if it is other type (ISO address, XNS address, etc)

            return null;

        }

    }

    private int getAddrType(InetAddress inetAddress) {

        int addressType = 0;

        if (inetAddress instanceof Inet4Address)

            addressType = Krb5.ADDRTYPE_INET;

        else if (inetAddress instanceof Inet6Address)

            addressType = Krb5.ADDRTYPE_INET6;

        return (addressType);

    }

    // implicit default not in Config.java

    public HostAddress() throws UnknownHostException {

        InetAddress inetAddress = getLocalInetAddress();

        addrType = getAddrType(inetAddress);

        address = inetAddress.getAddress();

    }

    /**

     * Creates a HostAddress from the specified address and address type.

     *

     * Warning: called by nativeccache.c.

     *

     * @param new_addrType the value of the address type which matches the defined

     *                       address family constants in the Berkeley Standard

     *                       Distributions of Unix.

     * @param new_address network address.

     * @exception KrbApErrException if address type and address length do not match defined value.

     *

     */

    public HostAddress(int new_addrType, byte[] new_address)

        throws KrbApErrException, UnknownHostException {

        switch(new_addrType) {

        case Krb5.ADDRTYPE_INET:        //Internet address

            if (new_address.length != 4)

                throw new KrbApErrException(0, "Invalid Internet address");

            break;

        case Krb5.ADDRTYPE_CHAOS:

            if (new_address.length != 2) //CHAOSnet address

                throw new KrbApErrException(0, "Invalid CHAOSnet address");

            break;

        case Krb5.ADDRTYPE_ISO:   // ISO address

            break;

        case Krb5.ADDRTYPE_IPX:   // XNS address

            if (new_address.length != 6)

                throw new KrbApErrException(0, "Invalid XNS address");

            break;

        case Krb5.ADDRTYPE_APPLETALK:  //AppleTalk DDP address

            if (new_address.length != 3)

                throw new KrbApErrException(0, "Invalid DDP address");

            break;

        case Krb5.ADDRTYPE_DECNET:    //DECnet Phase IV address

            if (new_address.length != 2)

                throw new KrbApErrException(0, "Invalid DECnet Phase IV address");

            break;

        case Krb5.ADDRTYPE_INET6:     //Internet IPv6 address

            if (new_address.length != 16)

                throw new KrbApErrException(0, "Invalid Internet IPv6 address");

            break;

        }

        addrType = new_addrType;

        if (new_address != null) {

           address = new_address.clone();

        }

        if (DEBUG) {

            if (addrType == Krb5.ADDRTYPE_INET ||

                addrType == Krb5.ADDRTYPE_INET6) {

                System.out.println("Host address is " +

                        InetAddress.getByAddress(address));

            }

        }

    }

    public HostAddress(InetAddress inetAddress) {

        addrType = getAddrType(inetAddress);

        address = inetAddress.getAddress();

    }

    /**

     * Constructs a host address from a single DER-encoded value.

     * @param encoding a single DER-encoded value.

     * @exception Asn1Exception if an error occurs while decoding an ASN1 encoded data.

     * @exception IOException if an I/O error occurs while reading encoded data.

     *

     */

    public HostAddress(DerValue encoding) throws Asn1Exception, IOException {

        DerValue der = encoding.getData().getDerValue();

        if ((der.getTag() & (byte)0x1F) == (byte)0x00) {

            addrType = der.getData().getBigInteger().intValue();

        }

        else

            throw new Asn1Exception(Krb5.ASN1_BAD_ID);

        der = encoding.getData().getDerValue();

        if ((der.getTag() & (byte)0x1F) == (byte)0x01) {

            address = der.getData().getOctetString();

        }

        else

            throw new Asn1Exception(Krb5.ASN1_BAD_ID);

        if (encoding.getData().available() > 0)

            throw new Asn1Exception(Krb5.ASN1_BAD_ID);

    }

    /**

         * Encodes a HostAddress object.

         * @return a byte array of encoded HostAddress object.

         * @exception Asn1Exception if an error occurs while decoding an ASN1 encoded data.

         * @exception IOException if an I/O error occurs while reading encoded data.

         *

         */

    public byte[] asn1Encode() throws Asn1Exception, IOException {

        DerOutputStream bytes = new DerOutputStream();

        DerOutputStream temp = new DerOutputStream();

        temp.putInteger(this.addrType);

        bytes.write(DerValue.createTag(DerValue.TAG_CONTEXT, true, (byte)0x00), temp);

        temp = new DerOutputStream();

        temp.putOctetString(address);

        bytes.write(DerValue.createTag(DerValue.TAG_CONTEXT, true, (byte)0x01), temp);

        temp = new DerOutputStream();

        temp.write(DerValue.tag_Sequence, bytes);

        return temp.toByteArray();

    }

    /**

     * Parses (unmarshal) a host address from a DER input stream.  This form

     * parsing might be used when expanding a value which is part of

         * a constructed sequence and uses explicitly tagged type.

     *

     * @exception Asn1Exception on error.

     * @exception IOException if an I/O error occurs while reading encoded data.

     * @param data the Der input stream value, which contains one or more marshaled value.

     * @param explicitTag tag number.

     * @param optional indicates if this data field is optional

     * @return an instance of HostAddress.

     *

     */

    public static HostAddress parse(DerInputStream data, byte explicitTag,

                                    boolean optional)

        throws Asn1Exception, IOException{

        if ((optional) &&

            (((byte)data.peekByte() & (byte)0x1F) != explicitTag)) {

            return null;

        }

        DerValue der = data.getDerValue();

        if (explicitTag != (der.getTag() & (byte)0x1F))  {

            throw new Asn1Exception(Krb5.ASN1_BAD_ID);

        }

        else {

            DerValue subDer = der.getData().getDerValue();

            return new HostAddress(subDer);

        }

    }

    @Override

    public String toString() {

        StringBuilder sb = new StringBuilder();

        sb.append(Arrays.toString(address));

        sb.append('(').append(addrType).append(')');

        return sb.toString();

    }

}