Inet4Address


1   /*
2    * @(#)Inet4Address.java    1.28 04/02/12
3    *
4    * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
5    * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6    */
7   
8   package java.net;
9   
10  import java.security.AccessController  ;
11  import java.io.ObjectStreamException  ;
12  import sun.security.action.*;
13  
14  /**
15   * This class represents an Internet Protocol version 4 (IPv4) address.
16   * Defined by <a HREF="http://www.ietf.org/rfc/rfc790.txt">
17   * <i>RFC&nbsp;790: Assigned Numbers</i></a>,
18   * <a HREF="http://www.ietf.org/rfc/rfc1918.txt">
19   * <i>RFC&nbsp;1918: Address Allocation for Private Internets</i></a>,
20   * and <a HREF="http://www.ietf.org/rfc/rfc2365.txt"><i>RFC&nbsp;2365:
21   * Administratively Scoped IP Multicast</i></a>
22   *
23   * <h4> <A NAME="format">Textual representation of IP addresses</a> </h4>
24   *
25   * Textual representation of IPv4 address used as input to methods
26   * takes one of the following forms:
27   *
28   * <blockquote><table cellpadding=0 cellspacing=0 summary="layout">
29   * <tr><td><tt>d.d.d.d</tt></td></tr>
30   * <tr><td><tt>d.d.d</tt></td></tr>
31   * <tr><td><tt>d.d</tt></td></tr>
32   * <tr><td><tt>d</tt></td></tr>
33   * </table></blockquote>
34   *
35   * <p> When four parts are specified, each is interpreted as a byte of
36   * data and assigned, from left to right, to the four bytes of an IPv4
37   * address.
38  
39   * <p> When a three part address is specified, the last part is
40   * interpreted as a 16-bit quantity and placed in the right most two
41   * bytes of the network address. This makes the three part address
42   * format convenient for specifying Class B net- work addresses as
43   * 128.net.host.
44   *
45   * <p> When a two part address is supplied, the last part is
46   * interpreted as a 24-bit quantity and placed in the right most three
47   * bytes of the network address. This makes the two part address
48   * format convenient for specifying Class A network addresses as
49   * net.host.
50   *
51   * <p> When only one part is given, the value is stored directly in
52   * the network address without any byte rearrangement.
53   *
54   * <p> For methods that return a textual representation as output
55   * value, the first form, i.e. a dotted-quad string, is used.
56   *
57   * <h4> The Scope of a Multicast Address </h4>
58   * 
59   * Historically the IPv4 TTL field in the IP header has doubled as a
60   * multicast scope field: a TTL of 0 means node-local, 1 means
61   * link-local, up through 32 means site-local, up through 64 means
62   * region-local, up through 128 means continent-local, and up through
63   * 255 are global. However, the administrative scoping is preferred.
64   * Please refer to <a HREF="http://www.ietf.org/rfc/rfc2365.txt">
65   * <i>RFC&nbsp;2365: Administratively Scoped IP Multicast</i></a>
66   */
67  
68  public final
69  class Inet4Address extends InetAddress   {
70      final static int INADDRSZ = 4;
71  
72      /** use serialVersionUID from InetAddress, but Inet4Address instance
73       *  is always replaced by an InetAddress instance before being
74       *  serialized */
75      private static final long serialVersionUID = 3286316764910316507L;
76  
77      /*
78       * Perform initializations.
79       */
80      static {
81          init();
82      }
83     
84      Inet4Address() {
85      super();
86      hostName = null;
87      address = 0;
88      family = IPv4;
89      }
90  
91      Inet4Address(String   hostName, byte addr[]) {
92      this.hostName = hostName;
93      this.family = IPv4;
94      if (addr != null) {
95          if (addr.length == INADDRSZ) {
96          address  = addr[3] & 0xFF;
97          address |= ((addr[2] << 8) & 0xFF00);
98          address |= ((addr[1] << 16) & 0xFF0000);
99          address |= ((addr[0] << 24) & 0xFF000000);
100         } 
101     } 
102     }
103     Inet4Address(String   hostName, int address) {
104     this.hostName = hostName;
105     this.family = IPv4;
106     this.address = address;
107     }
108 
109     /**
110      * Replaces the object to be serialized with an InetAddress object.
111      *
112      * @return the alternate object to be serialized.
113      *
114      * @throws ObjectStreamException if a new object replacing this
115      * object could not be created
116      */
117     private Object   writeReplace() throws ObjectStreamException   {
118     // will replace the to be serialized 'this' object
119     InetAddress   inet = new InetAddress  ();
120     inet.hostName = this.hostName;
121     inet.address = this.address;
122 
123     /**
124      * Prior to 1.4 an InetAddress was created with a family
125      * based on the platform AF_INET value (usually 2).
126          * For compatibility reasons we must therefore write the
127      * the InetAddress with this family.
128      */
129     inet.family = 2;
130 
131     return inet;
132     }
133 
134     /**
135      * Utility routine to check if the InetAddress is an
136      * IP multicast address. IP multicast address is a Class D
137      * address i.e first four bits of the address are 1110.
138      * @return a <code>boolean</code> indicating if the InetAddress is 
139      * an IP multicast address
140      * @since   JDK1.1
141      */
142     public boolean isMulticastAddress() {
143     return ((address & 0xf0000000) == 0xe0000000);
144     }
145 
146     /**
147      * Utility routine to check if the InetAddress in a wildcard address.
148      * @return a <code>boolean</code> indicating if the Inetaddress is
149      *         a wildcard address.
150      * @since 1.4
151      */    
152     public boolean isAnyLocalAddress() {
153     return address == 0;
154     }
155 
156     /**
157      * Utility routine to check if the InetAddress is a loopback address. 
158      *
159      * @return a <code>boolean</code> indicating if the InetAddress is 
160      * a loopback address; or false otherwise.
161      * @since 1.4
162      */
163     private static final int loopback = 2130706433; /* 127.0.0.1 */
164     public boolean isLoopbackAddress() {
165     /* 127.x.x.x */
166     byte[] byteAddr = getAddress();
167     return byteAddr[0] == 127;
168     }
169 
170     /**
171      * Utility routine to check if the InetAddress is an link local address. 
172      *
173      * @return a <code>boolean</code> indicating if the InetAddress is 
174      * a link local address; or false if address is not a link local unicast address.
175      * @since 1.4
176      */
177     public boolean isLinkLocalAddress() {
178     // link-local unicast in IPv4 (169.254.0.0/16)
179     // defined in "Documenting Special Use IPv4 Address Blocks
180     // that have been Registered with IANA" by Bill Manning
181     // draft-manning-dsua-06.txt
182     return (((address >>> 24) & 0xFF) == 169) 
183         && (((address >>> 16) & 0xFF) == 254);
184     }
185 
186     /**
187      * Utility routine to check if the InetAddress is a site local address. 
188      *
189      * @return a <code>boolean</code> indicating if the InetAddress is 
190      * a site local address; or false if address is not a site local unicast address.
191      * @since 1.4
192      */
193     public boolean isSiteLocalAddress() {
194     // refer to RFC 1918
195     // 10/8 prefix
196     // 172.16/12 prefix
197     // 192.168/16 prefix
198     return (((address >>> 24) & 0xFF) == 10)
199         || ((((address >>> 24) & 0xFF) == 172) 
200         && (((address >>> 16) & 0xF0) == 16))
201         || ((((address >>> 24) & 0xFF) == 192) 
202         && (((address >>> 16) & 0xFF) == 168));
203     }
204 
205     /**
206      * Utility routine to check if the multicast address has global scope.
207      *
208      * @return a <code>boolean</code> indicating if the address has 
209      *         is a multicast address of global scope, false if it is not 
210      *         of global scope or it is not a multicast address
211      * @since 1.4
212      */
213     public boolean isMCGlobal() {
214     // 224.0.1.0 to 238.255.255.255
215     byte[] byteAddr = getAddress();
216     return ((byteAddr[0] & 0xff) >= 224 && (byteAddr[0] & 0xff) <= 238 ) &&
217         !((byteAddr[0] & 0xff) == 224 && byteAddr[1] == 0 &&
218           byteAddr[2] == 0);
219     }
220 
221     /**
222      * Utility routine to check if the multicast address has node scope.
223      *
224      * @return a <code>boolean</code> indicating if the address has 
225      *         is a multicast address of node-local scope, false if it is not 
226      *         of node-local scope or it is not a multicast address
227      * @since 1.4
228      */
229     public boolean isMCNodeLocal() {
230     // unless ttl == 0
231     return false;
232     }
233 
234     /**
235      * Utility routine to check if the multicast address has link scope.
236      *
237      * @return a <code>boolean</code> indicating if the address has 
238      *         is a multicast address of link-local scope, false if it is not 
239      *         of link-local scope or it is not a multicast address
240      * @since 1.4
241      */
242     public boolean isMCLinkLocal() {
243     // 224.0.0/24 prefix and ttl == 1
244     return (((address >>> 24) & 0xFF) == 224) 
245         && (((address >>> 16) & 0xFF) == 0)
246         && (((address >>> 8) & 0xFF) == 0);
247     }
248 
249     /**
250      * Utility routine to check if the multicast address has site scope.
251      *
252      * @return a <code>boolean</code> indicating if the address has 
253      *         is a multicast address of site-local scope, false if it is not 
254      *         of site-local scope or it is not a multicast address
255      * @since 1.4
256      */
257     public boolean isMCSiteLocal() {
258     // 239.255/16 prefix or ttl < 32
259     return (((address >>> 24) & 0xFF) == 239) 
260         && (((address >>> 16) & 0xFF) == 255);
261     }
262 
263     /**
264      * Utility routine to check if the multicast address has organization scope.
265      *
266      * @return a <code>boolean</code> indicating if the address has 
267      *         is a multicast address of organization-local scope, 
268      *         false if it is not of organization-local scope 
269      *         or it is not a multicast address
270      * @since 1.4
271      */
272     public boolean isMCOrgLocal() {
273     // 239.192 - 239.195
274     return (((address >>> 24) & 0xFF) == 239) 
275         && (((address >>> 16) & 0xFF) >= 192)
276         && (((address >>> 16) & 0xFF) <= 195);
277     }  
278 
279     /**
280      * Returns the raw IP address of this <code>InetAddress</code>
281      * object. The result is in network byte order: the highest order
282      * byte of the address is in <code>getAddress()[0]</code>.
283      *
284      * @return  the raw IP address of this object.
285      */
286     public byte[] getAddress() {
287     byte[] addr = new byte[INADDRSZ];
288 
289     addr[0] = (byte) ((address >>> 24) & 0xFF);
290     addr[1] = (byte) ((address >>> 16) & 0xFF);
291     addr[2] = (byte) ((address >>> 8) & 0xFF);
292     addr[3] = (byte) (address & 0xFF);
293     return addr;
294     }
295 
296     /**
297      * Returns the IP address string in textual presentation form.
298      *
299      * @return  the raw IP address in a string format.
300      * @since   JDK1.0.2
301      */
302     public String   getHostAddress() {
303     return numericToTextFormat(getAddress());
304     }
305 
306     /**
307      * Returns a hashcode for this IP address.
308      *
309      * @return  a hash code value for this IP address.
310      */
311     public int hashCode() {
312     return address;
313     }
314     
315     /**
316      * Compares this object against the specified object.
317      * The result is <code>true</code> if and only if the argument is
318      * not <code>null</code> and it represents the same IP address as
319      * this object.
320      * <p>
321      * Two instances of <code>InetAddress</code> represent the same IP
322      * address if the length of the byte arrays returned by
323      * <code>getAddress</code> is the same for both, and each of the
324      * array components is the same for the byte arrays.
325      *
326      * @param   obj   the object to compare against.
327      * @return  <code>true</code> if the objects are the same;
328      *          <code>false</code> otherwise.
329      * @see     java.net.InetAddress#getAddress()
330      */
331     public boolean equals(Object   obj) { 
332     return (obj != null) && (obj instanceof Inet4Address  ) &&
333         (((InetAddress  )obj).address == address);    
334     }
335 
336     // Utilities
337     /* 
338      * Converts IPv4 binary address into a string suitable for presentation.
339      *
340      * @param src a byte array representing an IPv4 numeric address
341      * @return a String representing the IPv4 address in 
342      *         textual representation format
343      * @since 1.4
344      */
345     
346     static String   numericToTextFormat(byte[] src)
347     {
348     return (src[0] & 0xff) + "." + (src[1] & 0xff) + "." + (src[2] & 0xff) + "." + (src[3] & 0xff);
349     }
350     
351     /**
352      * Perform class load-time initializations.
353      */
354     private static native void init();
355 }
356
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