1 /*
2 * Copyright (c) 2000, 2019, 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
105 String formatted;
106
107 if (isUnresolved()) {
108 formatted = hostname + "/<unresolved>";
109 } else {
110 formatted = addr.toString();
111 if (addr instanceof Inet6Address) {
112 int i = formatted.lastIndexOf("/");
113 formatted = formatted.substring(0, i + 1)
114 + "[" + formatted.substring(i + 1) + "]";
115 }
116 }
117 return formatted + ":" + port;
118 }
119
120 @Override
121 public final boolean equals(Object obj) {
122 if (obj == null || !(obj instanceof InetSocketAddressHolder))
123 return false;
124 InetSocketAddressHolder that = (InetSocketAddressHolder)obj;
125 boolean sameIP;
126 if (addr != null)
127 sameIP = addr.equals(that.addr);
128 else if (hostname != null)
129 sameIP = (that.addr == null) &&
130 hostname.equalsIgnoreCase(that.hostname);
131 else
132 sameIP = (that.addr == null) && (that.hostname == null);
133 return sameIP && (port == that.port);
134 }
135
136 @Override
137 public final int hashCode() {
138 if (addr != null)
139 return addr.hashCode() + port;
140 if (hostname != null)
141 return hostname.toLowerCase().hashCode() + port;
142 return port;
143 }
144 }
145
146 private final transient InetSocketAddressHolder holder;
147
148 @java.io.Serial
149 private static final long serialVersionUID = 5076001401234631237L;
150
151 private static int checkPort(int port) {
152 if (port < 0 || port > 0xFFFF)
153 throw new IllegalArgumentException("port out of range:" + port);
154 return port;
155 }
156
157 private static String checkHost(String hostname) {
158 if (hostname == null)
159 throw new IllegalArgumentException("hostname can't be null");
160 return hostname;
161 }
162
163 /**
164 * Creates a socket address where the IP address is the wildcard address
165 * and the port number a specified value.
166 * <p>
167 * A valid port value is between 0 and 65535.
168 * A port number of {@code zero} will let the system pick up an
169 * ephemeral port in a {@code bind} operation.
170 *
171 * @param port The port number
172 * @throws IllegalArgumentException if the port parameter is outside the specified
173 * range of valid port values.
174 */
175 public InetSocketAddress(int port) {
176 this(InetAddress.anyLocalAddress(), port);
177 }
178
179 /**
180 *
181 * Creates a socket address from an IP address and a port number.
182 * <p>
183 * A valid port value is between 0 and 65535.
184 * A port number of {@code zero} will let the system pick up an
185 * ephemeral port in a {@code bind} operation.
186 * <P>
187 * A {@code null} address will assign the <i>wildcard</i> address.
188 *
189 * @param addr The IP address
190 * @param port The port number
191 * @throws IllegalArgumentException if the port parameter is outside the specified
192 * range of valid port values.
193 */
194 public InetSocketAddress(InetAddress addr, int port) {
195 holder = new InetSocketAddressHolder(
196 null,
197 addr == null ? InetAddress.anyLocalAddress() : addr,
198 checkPort(port));
199 }
200
201 /**
202 *
203 * Creates a socket address from a hostname and a port number.
204 * <p>
205 * An attempt will be made to resolve the hostname into an InetAddress.
206 * If that attempt fails, the address will be flagged as <I>unresolved</I>.
207 * <p>
208 * If there is a security manager, its {@code checkConnect} method
209 * is called with the host name as its argument to check the permission
210 * to resolve it. This could result in a SecurityException.
211 * <P>
212 * A valid port value is between 0 and 65535.
213 * A port number of {@code zero} will let the system pick up an
214 * ephemeral port in a {@code bind} operation.
215 *
216 * @param hostname the Host name
217 * @param port The port number
218 * @throws IllegalArgumentException if the port parameter is outside the range
219 * of valid port values, or if the hostname parameter is {@code null}.
220 * @throws SecurityException if a security manager is present and
221 * permission to resolve the host name is
222 * denied.
223 * @see #isUnresolved()
224 */
225 public InetSocketAddress(String hostname, int port) {
226 checkHost(hostname);
227 InetAddress addr = null;
228 String host = null;
229 try {
230 addr = InetAddress.getByName(hostname);
231 } catch(UnknownHostException e) {
232 host = hostname;
233 }
234 holder = new InetSocketAddressHolder(host, addr, checkPort(port));
235 }
236
237 // private constructor for creating unresolved instances
238 private InetSocketAddress(int port, String hostname) {
239 holder = new InetSocketAddressHolder(hostname, null, port);
240 }
241
242 /**
243 *
244 * Creates an unresolved socket address from a hostname and a port number.
245 * <p>
246 * No attempt will be made to resolve the hostname into an InetAddress.
247 * The address will be flagged as <I>unresolved</I>.
248 * <p>
249 * A valid port value is between 0 and 65535.
250 * A port number of {@code zero} will let the system pick up an
251 * ephemeral port in a {@code bind} operation.
252 *
253 * @param host the Host name
254 * @param port The port number
255 * @throws IllegalArgumentException if the port parameter is outside
256 * the range of valid port values, or if the hostname
257 * parameter is {@code null}.
258 * @see #isUnresolved()
259 * @return an {@code InetSocketAddress} representing the unresolved
260 * socket address
261 * @since 1.5
262 */
263 public static InetSocketAddress createUnresolved(String host, int port) {
264 return new InetSocketAddress(checkPort(port), checkHost(host));
265 }
266
267 /**
268 * @serialField hostname String
269 * @serialField addr InetAddress
270 * @serialField port int
271 */
272 @java.io.Serial
273 private static final ObjectStreamField[] serialPersistentFields = {
274 new ObjectStreamField("hostname", String.class),
275 new ObjectStreamField("addr", InetAddress.class),
276 new ObjectStreamField("port", int.class)};
277
278 @java.io.Serial
279 private void writeObject(ObjectOutputStream out)
280 throws IOException
281 {
282 // Don't call defaultWriteObject()
283 ObjectOutputStream.PutField pfields = out.putFields();
284 pfields.put("hostname", holder.hostname);
285 pfields.put("addr", holder.addr);
286 pfields.put("port", holder.port);
287 out.writeFields();
288 }
289
290 @java.io.Serial
291 private void readObject(ObjectInputStream in)
292 throws IOException, ClassNotFoundException
293 {
294 // Don't call defaultReadObject()
295 ObjectInputStream.GetField oisFields = in.readFields();
296 final String oisHostname = (String)oisFields.get("hostname", null);
297 final InetAddress oisAddr = (InetAddress)oisFields.get("addr", null);
298 final int oisPort = oisFields.get("port", -1);
299
300 // Check that our invariants are satisfied
301 checkPort(oisPort);
302 if (oisHostname == null && oisAddr == null)
303 throw new InvalidObjectException("hostname and addr " +
304 "can't both be null");
305
306 InetSocketAddressHolder h = new InetSocketAddressHolder(oisHostname,
307 oisAddr,
308 oisPort);
309 UNSAFE.putReference(this, FIELDS_OFFSET, h);
310 }
311
312 @java.io.Serial
313 private void readObjectNoData()
314 throws ObjectStreamException
315 {
316 throw new InvalidObjectException("Stream data required");
317 }
318
319 private static final jdk.internal.misc.Unsafe UNSAFE
320 = jdk.internal.misc.Unsafe.getUnsafe();
321 private static final long FIELDS_OFFSET
322 = UNSAFE.objectFieldOffset(InetSocketAddress.class, "holder");
323
324 /**
325 * Gets the port number.
326 *
327 * @return the port number.
328 */
329 public final int getPort() {
330 return holder.getPort();
331 }
332
333 /**
334 * Gets the {@code InetAddress}.
335 *
336 * @return the InetAddress or {@code null} if it is unresolved.
337 */
338 public final InetAddress getAddress() {
339 return holder.getAddress();
340 }
341
342 /**
343 * Gets the {@code hostname}.
344 * Note: This method may trigger a name service reverse lookup if the
345 * address was created with a literal IP address.
346 *
347 * @return the hostname part of the address.
348 */
349 public final String getHostName() {
350 return holder.getHostName();
351 }
352
353 /**
354 * Returns the hostname, or the String form of the address if it
355 * doesn't have a hostname (it was created using a literal).
356 * This has the benefit of <b>not</b> attempting a reverse lookup.
357 *
358 * @return the hostname, or String representation of the address.
359 * @since 1.7
360 */
361 public final String getHostString() {
362 return holder.getHostString();
363 }
364
365 /**
366 * Checks whether the address has been resolved or not.
367 *
368 * @return {@code true} if the hostname couldn't be resolved into
369 * an {@code InetAddress}.
370 */
371 public final boolean isUnresolved() {
372 return holder.isUnresolved();
373 }
374
375 /**
376 * Constructs a string representation of this InetSocketAddress.
377 * This String is constructed by calling toString() on the InetAddress
378 * and concatenating the port number (with a colon). If the address
379 * is an IPv6 address, the IPv6 literal is enclosed in square brackets.
380 * If the address is {@linkplain #isUnresolved() unresolved},
381 * {@code <unresolved>} is displayed in place of the address literal.
382 *
383 * @return a string representation of this object.
384 */
385 @Override
386 public String toString() {
387 return holder.toString();
388 }
389
390 /**
391 * Compares this object against the specified object.
392 * The result is {@code true} if and only if the argument is
393 * not {@code null} and it represents the same address as
394 * this object.
395 * <p>
396 * Two instances of {@code InetSocketAddress} represent the same
397 * address if both the InetAddresses (or hostnames if it is unresolved) and port
398 * numbers are equal.
399 * If both addresses are unresolved, then the hostname and the port number
400 * are compared.
401 *
402 * Note: Hostnames are case insensitive. e.g. "FooBar" and "foobar" are
403 * considered equal.
404 *
405 * @param obj the object to compare against.
406 * @return {@code true} if the objects are the same;
407 * {@code false} otherwise.
408 * @see java.net.InetAddress#equals(java.lang.Object)
409 */
410 @Override
411 public final boolean equals(Object obj) {
412 if (obj == null || !(obj instanceof InetSocketAddress))
413 return false;
414 return holder.equals(((InetSocketAddress) obj).holder);
415 }
416
417 /**
418 * Returns a hashcode for this socket address.
419 *
420 * @return a hash code value for this socket address.
421 */
422 @Override
423 public final int hashCode() {
424 return holder.hashCode();
425 }
426 }