1 /*
2 * Copyright (c) 2000, 2018, 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 package java.net;
26
27 import java.io.IOException;
28 import java.io.InvalidObjectException;
29 import java.io.ObjectInputStream;
30 import java.io.ObjectOutputStream;
31 import java.io.ObjectStreamException;
32 import java.io.ObjectStreamField;
33
34 /**
35 *
36 * This class implements an IP Socket Address (IP address + port number)
37 * It can also be a pair (hostname + port number), in which case an attempt
38 * will be made to resolve the hostname. If resolution fails then the address
39 * is said to be <I>unresolved</I> but can still be used on some circumstances
40 * like connecting through a proxy.
41 * <p>
42 * It provides an immutable object used by sockets for binding, connecting, or
43 * as returned values.
44 * <p>
45 * The <i>wildcard</i> is a special local IP address. It usually means "any"
46 * and can only be used for {@code bind} operations.
47 *
48 * @see java.net.Socket
49 * @see java.net.ServerSocket
50 * @since 1.4
51 */
52 public class InetSocketAddress
53 extends SocketAddress
54 {
55 // Private implementation class pointed to by all public methods.
56 private static class InetSocketAddressHolder {
57 // The hostname of the Socket Address
58 private String hostname;
59 // The IP address of the Socket Address
60 private InetAddress addr;
61 // The port number of the Socket Address
62 private int port;
63
64 private InetSocketAddressHolder(String hostname, InetAddress addr, int port) {
65 this.hostname = hostname;
66 this.addr = addr;
67 this.port = port;
68 }
69
70 private int getPort() {
71 return port;
72 }
73
74 private InetAddress getAddress() {
75 return addr;
76 }
77
78 private String getHostName() {
79 if (hostname != null)
80 return hostname;
81 if (addr != null)
82 return addr.getHostName();
83 return null;
84 }
85
86 private String getHostString() {
87 if (hostname != null)
88 return hostname;
89 if (addr != null) {
90 if (addr.holder().getHostName() != null)
91 return addr.holder().getHostName();
92 else
93 return addr.getHostAddress();
94 }
95 return null;
96 }
97
98 private boolean isUnresolved() {
99 return addr == null;
100 }
101
102 @Override
103 public String toString() {
104 if (isUnresolved()) {
105 return hostname + ":" + port;
106 } else {
107 return addr.toString() + ":" + port;
108 }
109 }
110
111 @Override
112 public final boolean equals(Object obj) {
113 if (obj == null || !(obj instanceof InetSocketAddressHolder))
114 return false;
115 InetSocketAddressHolder that = (InetSocketAddressHolder)obj;
116 boolean sameIP;
117 if (addr != null)
118 sameIP = addr.equals(that.addr);
119 else if (hostname != null)
120 sameIP = (that.addr == null) &&
121 hostname.equalsIgnoreCase(that.hostname);
122 else
123 sameIP = (that.addr == null) && (that.hostname == null);
124 return sameIP && (port == that.port);
125 }
126
127 @Override
128 public final int hashCode() {
129 if (addr != null)
130 return addr.hashCode() + port;
131 if (hostname != null)
132 return hostname.toLowerCase().hashCode() + port;
133 return port;
134 }
135 }
136
137 private final transient InetSocketAddressHolder holder;
138
139 @java.io.Serial
140 private static final long serialVersionUID = 5076001401234631237L;
141
142 private static int checkPort(int port) {
143 if (port < 0 || port > 0xFFFF)
144 throw new IllegalArgumentException("port out of range:" + port);
145 return port;
146 }
147
148 private static String checkHost(String hostname) {
149 if (hostname == null)
150 throw new IllegalArgumentException("hostname can't be null");
151 return hostname;
152 }
153
154 /**
155 * Creates a socket address where the IP address is the wildcard address
156 * and the port number a specified value.
157 * <p>
158 * A valid port value is between 0 and 65535.
159 * A port number of {@code zero} will let the system pick up an
160 * ephemeral port in a {@code bind} operation.
161 *
162 * @param port The port number
163 * @throws IllegalArgumentException if the port parameter is outside the specified
164 * range of valid port values.
165 */
166 public InetSocketAddress(int port) {
167 this(InetAddress.anyLocalAddress(), port);
168 }
169
170 /**
171 *
172 * Creates a socket address from an IP address and a port number.
173 * <p>
174 * A valid port value is between 0 and 65535.
175 * A port number of {@code zero} will let the system pick up an
176 * ephemeral port in a {@code bind} operation.
177 * <P>
178 * A {@code null} address will assign the <i>wildcard</i> address.
179 *
180 * @param addr The IP address
181 * @param port The port number
182 * @throws IllegalArgumentException if the port parameter is outside the specified
183 * range of valid port values.
184 */
185 public InetSocketAddress(InetAddress addr, int port) {
186 holder = new InetSocketAddressHolder(
187 null,
188 addr == null ? InetAddress.anyLocalAddress() : addr,
189 checkPort(port));
190 }
191
192 /**
193 *
194 * Creates a socket address from a hostname and a port number.
195 * <p>
196 * An attempt will be made to resolve the hostname into an InetAddress.
197 * If that attempt fails, the address will be flagged as <I>unresolved</I>.
198 * <p>
199 * If there is a security manager, its {@code checkConnect} method
200 * is called with the host name as its argument to check the permission
201 * to resolve it. This could result in a SecurityException.
202 * <P>
203 * A valid port value is between 0 and 65535.
204 * A port number of {@code zero} will let the system pick up an
205 * ephemeral port in a {@code bind} operation.
206 *
207 * @param hostname the Host name
208 * @param port The port number
209 * @throws IllegalArgumentException if the port parameter is outside the range
210 * of valid port values, or if the hostname parameter is {@code null}.
211 * @throws SecurityException if a security manager is present and
212 * permission to resolve the host name is
213 * denied.
214 * @see #isUnresolved()
215 */
216 public InetSocketAddress(String hostname, int port) {
217 checkHost(hostname);
218 InetAddress addr = null;
219 String host = null;
220 try {
221 addr = InetAddress.getByName(hostname);
222 } catch(UnknownHostException e) {
223 host = hostname;
224 }
225 holder = new InetSocketAddressHolder(host, addr, checkPort(port));
226 }
227
228 // private constructor for creating unresolved instances
229 private InetSocketAddress(int port, String hostname) {
230 holder = new InetSocketAddressHolder(hostname, null, port);
231 }
232
233 /**
234 *
235 * Creates an unresolved socket address from a hostname and a port number.
236 * <p>
237 * No attempt will be made to resolve the hostname into an InetAddress.
238 * The address will be flagged as <I>unresolved</I>.
239 * <p>
240 * A valid port value is between 0 and 65535.
241 * A port number of {@code zero} will let the system pick up an
242 * ephemeral port in a {@code bind} operation.
243 *
244 * @param host the Host name
245 * @param port The port number
246 * @throws IllegalArgumentException if the port parameter is outside
247 * the range of valid port values, or if the hostname
248 * parameter is {@code null}.
249 * @see #isUnresolved()
250 * @return an {@code InetSocketAddress} representing the unresolved
251 * socket address
252 * @since 1.5
253 */
254 public static InetSocketAddress createUnresolved(String host, int port) {
255 return new InetSocketAddress(checkPort(port), checkHost(host));
256 }
257
258 /**
259 * @serialField hostname String
260 * @serialField addr InetAddress
261 * @serialField port int
262 */
263 @java.io.Serial
264 private static final ObjectStreamField[] serialPersistentFields = {
265 new ObjectStreamField("hostname", String.class),
266 new ObjectStreamField("addr", InetAddress.class),
267 new ObjectStreamField("port", int.class)};
268
269 @java.io.Serial
270 private void writeObject(ObjectOutputStream out)
271 throws IOException
272 {
273 // Don't call defaultWriteObject()
274 ObjectOutputStream.PutField pfields = out.putFields();
275 pfields.put("hostname", holder.hostname);
276 pfields.put("addr", holder.addr);
277 pfields.put("port", holder.port);
278 out.writeFields();
279 }
280
281 @java.io.Serial
282 private void readObject(ObjectInputStream in)
283 throws IOException, ClassNotFoundException
284 {
285 // Don't call defaultReadObject()
286 ObjectInputStream.GetField oisFields = in.readFields();
287 final String oisHostname = (String)oisFields.get("hostname", null);
288 final InetAddress oisAddr = (InetAddress)oisFields.get("addr", null);
289 final int oisPort = oisFields.get("port", -1);
290
291 // Check that our invariants are satisfied
292 checkPort(oisPort);
293 if (oisHostname == null && oisAddr == null)
294 throw new InvalidObjectException("hostname and addr " +
295 "can't both be null");
296
297 InetSocketAddressHolder h = new InetSocketAddressHolder(oisHostname,
298 oisAddr,
299 oisPort);
300 UNSAFE.putReference(this, FIELDS_OFFSET, h);
301 }
302
303 @java.io.Serial
304 private void readObjectNoData()
305 throws ObjectStreamException
306 {
307 throw new InvalidObjectException("Stream data required");
308 }
309
310 private static final jdk.internal.misc.Unsafe UNSAFE
311 = jdk.internal.misc.Unsafe.getUnsafe();
312 private static final long FIELDS_OFFSET
313 = UNSAFE.objectFieldOffset(InetSocketAddress.class, "holder");
314
315 /**
316 * Gets the port number.
317 *
318 * @return the port number.
319 */
320 public final int getPort() {
321 return holder.getPort();
322 }
323
324 /**
325 * Gets the {@code InetAddress}.
326 *
327 * @return the InetAddress or {@code null} if it is unresolved.
328 */
329 public final InetAddress getAddress() {
330 return holder.getAddress();
331 }
332
333 /**
334 * Gets the {@code hostname}.
335 * Note: This method may trigger a name service reverse lookup if the
336 * address was created with a literal IP address.
337 *
338 * @return the hostname part of the address.
339 */
340 public final String getHostName() {
341 return holder.getHostName();
342 }
343
344 /**
345 * Returns the hostname, or the String form of the address if it
346 * doesn't have a hostname (it was created using a literal).
347 * This has the benefit of <b>not</b> attempting a reverse lookup.
348 *
349 * @return the hostname, or String representation of the address.
350 * @since 1.7
351 */
352 public final String getHostString() {
353 return holder.getHostString();
354 }
355
356 /**
357 * Checks whether the address has been resolved or not.
358 *
359 * @return {@code true} if the hostname couldn't be resolved into
360 * an {@code InetAddress}.
361 */
362 public final boolean isUnresolved() {
363 return holder.isUnresolved();
364 }
365
366 /**
367 * Constructs a string representation of this InetSocketAddress.
368 * This String is constructed by calling toString() on the InetAddress
369 * and concatenating the port number (with a colon). If the address
370 * is unresolved then the part before the colon will only contain the hostname.
371 *
372 * @return a string representation of this object.
373 */
374 @Override
375 public String toString() {
376 return holder.toString();
377 }
378
379 /**
380 * Compares this object against the specified object.
381 * The result is {@code true} if and only if the argument is
382 * not {@code null} and it represents the same address as
383 * this object.
384 * <p>
385 * Two instances of {@code InetSocketAddress} represent the same
386 * address if both the InetAddresses (or hostnames if it is unresolved) and port
387 * numbers are equal.
388 * If both addresses are unresolved, then the hostname and the port number
389 * are compared.
390 *
391 * Note: Hostnames are case insensitive. e.g. "FooBar" and "foobar" are
392 * considered equal.
393 *
394 * @param obj the object to compare against.
395 * @return {@code true} if the objects are the same;
396 * {@code false} otherwise.
397 * @see java.net.InetAddress#equals(java.lang.Object)
398 */
399 @Override
400 public final boolean equals(Object obj) {
401 if (obj == null || !(obj instanceof InetSocketAddress))
402 return false;
403 return holder.equals(((InetSocketAddress) obj).holder);
404 }
405
406 /**
407 * Returns a hashcode for this socket address.
408 *
409 * @return a hash code value for this socket address.
410 */
411 @Override
412 public final int hashCode() {
413 return holder.hashCode();
414 }
415 }