1 /*
2  * Copyright (c) 2005, 2013, 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  * This class represents a Network Interface address. In short it's an
30  * IP address, a subnet mask and a broadcast address when the address is
31  * an IPv4 one. An IP address and a network prefix length in the case
32  * of IPv6 address.
33  *
34  * @see java.net.NetworkInterface
35  * @since 1.6
36  */
37 public class InterfaceAddress {
38     private InetAddress address = null;
39     private Inet4Address broadcast = null;
40     private short        maskLength = 0;
41 
42     /*
43      * Package private constructor. Can't be built directly, instances are
44      * obtained through the NetworkInterface class.
45      */
InterfaceAddress()46     InterfaceAddress() {
47     }
48 
InterfaceAddress(InetAddress address, Inet4Address broadcast, InetAddress netmask)49     InterfaceAddress(InetAddress address, Inet4Address broadcast, InetAddress netmask) {
50         this.address = address;
51         this.broadcast = broadcast;
52         this.maskLength = countPrefixLength(netmask);
53     }
54 
55     /**
56      * Counts the prefix length for the netmask address.
57      *
58      * A valid netmask address must start with a continuous sequence of 1, followed by a continuous
59      * sequence of 0.
60      */
countPrefixLength(InetAddress netmask)61     private short countPrefixLength(InetAddress netmask) {
62         short count = 0;
63         for (byte b : netmask.getAddress()) {
64             for (; b != 0; b <<= 1, ++count);
65         }
66         return count;
67     }
68 
69     /**
70      * Returns an {@code InetAddress} for this address.
71      *
72      * @return the {@code InetAddress} for this address.
73      */
getAddress()74     public InetAddress getAddress() {
75         return address;
76     }
77 
78     /**
79      * Returns an {@code InetAddress} for the broadcast address
80      * for this InterfaceAddress.
81      * <p>
82      * Only IPv4 networks have broadcast address therefore, in the case
83      * of an IPv6 network, {@code null} will be returned.
84      *
85      * @return the {@code InetAddress} representing the broadcast
86      *         address or {@code null} if there is no broadcast address.
87      */
getBroadcast()88     public InetAddress getBroadcast() {
89         return broadcast;
90     }
91 
92     /**
93      * Returns the network prefix length for this address. This is also known
94      * as the subnet mask in the context of IPv4 addresses.
95      * Typical IPv4 values would be 8 (255.0.0.0), 16 (255.255.0.0)
96      * or 24 (255.255.255.0). <p>
97      * Typical IPv6 values would be 128 (::1/128) or 10 (fe80::203:baff:fe27:1243/10)
98      *
99      * @return a {@code short} representing the prefix length for the
100      *         subnet of that address.
101      */
getNetworkPrefixLength()102      public short getNetworkPrefixLength() {
103         return maskLength;
104     }
105 
106     /**
107      * Compares this object against the specified object.
108      * The result is {@code true} if and only if the argument is
109      * not {@code null} and it represents the same interface address as
110      * this object.
111      * <p>
112      * Two instances of {@code InterfaceAddress} represent the same
113      * address if the InetAddress, the prefix length and the broadcast are
114      * the same for both.
115      *
116      * @param   obj   the object to compare against.
117      * @return  {@code true} if the objects are the same;
118      *          {@code false} otherwise.
119      * @see     java.net.InterfaceAddress#hashCode()
120      */
equals(Object obj)121     public boolean equals(Object obj) {
122         if (!(obj instanceof InterfaceAddress)) {
123             return false;
124         }
125         InterfaceAddress cmp = (InterfaceAddress) obj;
126         if ( !(address == null ? cmp.address == null : address.equals(cmp.address)) )
127             return false;
128         if ( !(broadcast  == null ? cmp.broadcast == null : broadcast.equals(cmp.broadcast)) )
129             return false;
130         if (maskLength != cmp.maskLength)
131             return false;
132         return true;
133     }
134 
135     /**
136      * Returns a hashcode for this Interface address.
137      *
138      * @return  a hash code value for this Interface address.
139      */
hashCode()140     public int hashCode() {
141         return address.hashCode() + ((broadcast != null) ? broadcast.hashCode() : 0) + maskLength;
142     }
143 
144     /**
145      * Converts this Interface address to a {@code String}. The
146      * string returned is of the form: InetAddress / prefix length [ broadcast address ].
147      *
148      * @return  a string representation of this Interface address.
149      */
toString()150     public String toString() {
151         return address + "/" + maskLength + " [" + broadcast + "]";
152     }
153 
154 }
155