1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * https://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.net.util;
18
19 import java.util.Iterator;
20 import java.util.regex.Matcher;
21 import java.util.regex.Pattern;
22 import java.util.stream.Stream;
23 import java.util.stream.StreamSupport;
24
25 /**
26 * Performs subnet calculations given a network address and a subnet mask.
27 *
28 * @see <a href="https://datatracker.ietf.org/doc/html/rfc1519">Classless Inter-Domain Routing (CIDR): an Address Assignment and Aggregation Strategy</a>
29 * @see SubnetUtils6
30 * @since 2.0
31 */
32 public class SubnetUtils {
33
34 /**
35 * Allows an object to be the target of the "for-each loop" statement for a SubnetInfo.
36 */
37 private static final class SubnetAddressStringIterable implements Iterable<String> {
38
39 private final SubnetInfo subnetInfo;
40
41 /**
42 * Constructs a new instance.
43 *
44 * @param subnetInfo the SubnetInfo to iterate.
45 */
46 private SubnetAddressStringIterable(final SubnetInfo subnetInfo) {
47 this.subnetInfo = subnetInfo;
48 }
49
50 @Override
51 public Iterator<String> iterator() {
52 return new SubnetAddressStringIterator(subnetInfo);
53 }
54 }
55
56 /**
57 * Iterates over a SubnetInfo.
58 */
59 private static final class SubnetAddressStringIterator implements Iterator<String> {
60
61 private int currentAddress;
62
63 private final SubnetInfo subnetInfo;
64
65 /**
66 * Constructs a new instance.
67 *
68 * @param subnetInfo the SubnetInfo to iterate.
69 */
70 private SubnetAddressStringIterator(final SubnetInfo subnetInfo) {
71 this.subnetInfo = subnetInfo;
72 currentAddress = subnetInfo.low();
73 }
74
75 @Override
76 public boolean hasNext() {
77 return subnetInfo.getAddressCountLong() > 0 && currentAddress <= subnetInfo.high();
78 }
79
80 @Override
81 public String next() {
82 return format(toArray4(currentAddress++));
83 }
84 }
85
86 /**
87 * Contains subnet summary information.
88 */
89 public final class SubnetInfo {
90
91 /** Mask to convert unsigned int to a long (i.e. keep 32 bits). */
92 private static final long UNSIGNED_INT_MASK = 0x0FFFFFFFFL;
93
94 private SubnetInfo() {
95 }
96
97 /**
98 * Converts a dotted decimal format address to a packed integer format.
99 *
100 * @param address a dotted decimal format address.
101 * @return packed integer formatted int.
102 */
103 public int asInteger(final String address) {
104 return toInteger(address);
105 }
106
107 private long broadcastLong() {
108 return broadcast & UNSIGNED_INT_MASK;
109 }
110
111 /**
112 * Gets this instance's address into a dotted decimal String.
113 *
114 * @return a dotted decimal String.
115 */
116 public String getAddress() {
117 return format(toArray4(address));
118 }
119
120 /**
121 * Gets the count of available addresses. Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false.
122 *
123 * @return the count of addresses, may be zero.
124 * @throws RuntimeException if the correct count is greater than {@code Integer.MAX_VALUE}
125 * @deprecated (3.4) use {@link #getAddressCountLong()} instead
126 */
127 @Deprecated
128 public int getAddressCount() {
129 final long countLong = getAddressCountLong();
130 if (countLong > Integer.MAX_VALUE) {
131 throw new IllegalStateException("Count is larger than an integer: " + countLong);
132 }
133 // Cannot be negative here
134 return (int) countLong;
135 }
136
137 /**
138 * Gets the count of available addresses. Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false.
139 *
140 * @return the count of addresses, may be zero.
141 * @since 3.4
142 */
143 public long getAddressCountLong() {
144 final long b = broadcastLong();
145 final long n = networkLong();
146 final long count = b - n + (isInclusiveHostCount() ? 1 : -1);
147 return count < 0 ? 0 : count;
148 }
149
150 /**
151 * Gets all addresses in this subnet, the return array could be huge.
152 * <p>
153 * For large ranges, you can iterate or stream over the addresses instead using {@link #iterableAddressStrings()} or {@link #streamAddressStrings()}.
154 * </p>
155 *
156 * @return all addresses in this subnet.
157 * @see #iterableAddressStrings()
158 * @see #streamAddressStrings()
159 */
160 public String[] getAllAddresses() {
161 final int ct = getAddressCount();
162 final String[] addresses = new String[ct];
163 if (ct == 0) {
164 return addresses;
165 }
166 final int high = high();
167 for (int add = low(), j = 0; add <= high; ++add, ++j) {
168 addresses[j] = format(toArray4(add));
169 }
170 return addresses;
171 }
172
173 /**
174 * Gets the broadcast address for this subnet.
175 *
176 * @return the broadcast address for this subnet.
177 */
178 public String getBroadcastAddress() {
179 return format(toArray4(broadcast));
180 }
181
182 /**
183 * Gets the CIDR signature for this subnet.
184 *
185 * @return the CIDR signature for this subnet.
186 */
187 public String getCidrSignature() {
188 return format(toArray4(address)) + "/" + Integer.bitCount(netmask);
189 }
190
191 /**
192 * Gets the high address as a dotted IP address. Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false.
193 *
194 * @return the IP address in dotted format, may be "0.0.0.0" if there is no valid address
195 */
196 public String getHighAddress() {
197 return format(toArray4(high()));
198 }
199
200 /**
201 * Gets the low address as a dotted IP address. Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false.
202 *
203 * @return the IP address in dotted format, may be "0.0.0.0" if there is no valid address
204 */
205 public String getLowAddress() {
206 return format(toArray4(low()));
207 }
208
209 /**
210 * Gets the network mask for this subnet.
211 *
212 * @return the network mask for this subnet.
213 */
214 public String getNetmask() {
215 return format(toArray4(netmask));
216 }
217
218 /**
219 * Gets the network address for this subnet.
220 *
221 * @return the network address for this subnet.
222 */
223 public String getNetworkAddress() {
224 return format(toArray4(network));
225 }
226
227 /**
228 * Gets the next address for this subnet.
229 *
230 * @return the next address for this subnet.
231 */
232 public String getNextAddress() {
233 return format(toArray4(address + 1));
234 }
235
236 /**
237 * Gets the previous address for this subnet.
238 *
239 * @return the previous address for this subnet.
240 */
241 public String getPreviousAddress() {
242 return format(toArray4(address - 1));
243 }
244
245 private int high() {
246 return isInclusiveHostCount() ? broadcast : broadcastLong() - networkLong() > 1 ? broadcast - 1 : 0;
247 }
248
249 /**
250 * Tests if the parameter {@code address} is in the range of usable endpoint addresses for this subnet. This excludes the network and broadcast
251 * addresses by default. Use {@link SubnetUtils#setInclusiveHostCount(boolean)} to change this.
252 *
253 * @param address the address to check
254 * @return true if it is in range
255 * @since 3.4 (made public)
256 */
257 public boolean isInRange(final int address) {
258 if (address == 0) { // cannot ever be in range; rejecting now avoids problems with CIDR/31,32
259 return false;
260 }
261 final long addLong = address & UNSIGNED_INT_MASK;
262 final long lowLong = low() & UNSIGNED_INT_MASK;
263 final long highLong = high() & UNSIGNED_INT_MASK;
264 return addLong >= lowLong && addLong <= highLong;
265 }
266
267 /**
268 * Tests if the parameter {@code address} is in the range of usable endpoint addresses for this subnet. This excludes the network and broadcast
269 * addresses. Use {@link SubnetUtils#setInclusiveHostCount(boolean)} to change this.
270 *
271 * @param address A dot-delimited IPv4 address, e.g. "192.168.0.1"
272 * @return True if in range, false otherwise
273 */
274 public boolean isInRange(final String address) {
275 return isInRange(toInteger(address));
276 }
277
278 /**
279 * Creates a new Iterable of address Strings.
280 *
281 * @return a new Iterable of address Strings
282 * @see #getAllAddresses()
283 * @see #streamAddressStrings()
284 * @since 3.12.0
285 */
286 public Iterable<String> iterableAddressStrings() {
287 return new SubnetAddressStringIterable(this);
288 }
289
290 private int low() {
291 return isInclusiveHostCount() ? network : broadcastLong() - networkLong() > 1 ? network + 1 : 0;
292 }
293
294 /** Long versions of the values (as unsigned int) which are more suitable for range checking. */
295 private long networkLong() {
296 return network & UNSIGNED_INT_MASK;
297 }
298
299 /**
300 * Creates a new Stream of address Strings.
301 *
302 * @return a new Stream of address Strings.
303 * @see #getAllAddresses()
304 * @see #iterableAddressStrings()
305 * @since 3.12.0
306 */
307 public Stream<String> streamAddressStrings() {
308 return StreamSupport.stream(iterableAddressStrings().spliterator(), false);
309 }
310
311 /**
312 * {@inheritDoc}
313 *
314 * @since 2.2
315 */
316 @Override
317 public String toString() {
318 final StringBuilder buf = new StringBuilder();
319 // @formatter:off
320 buf.append("CIDR Signature:\t[").append(getCidrSignature()).append("]\n")
321 .append(" Netmask: [").append(getNetmask()).append("]\n")
322 .append(" Network: [").append(getNetworkAddress()).append("]\n")
323 .append(" Broadcast: [").append(getBroadcastAddress()).append("]\n")
324 .append(" First address: [").append(getLowAddress()).append("]\n")
325 .append(" Last address: [").append(getHighAddress()).append("]\n")
326 .append(" Address Count: [").append(getAddressCountLong()).append("]\n");
327 // @formatter:on
328 return buf.toString();
329 }
330 }
331
332 private static final String IP_ADDRESS = "(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})";
333
334 private static final String SLASH_FORMAT = IP_ADDRESS + "/(\\d{1,2})"; // 0 -> 32
335
336 private static final Pattern ADDRESS_PATTERN = Pattern.compile(IP_ADDRESS);
337 private static final Pattern CIDR_PATTERN = Pattern.compile(SLASH_FORMAT);
338 private static final int NBITS = 32;
339 private static final String PARSE_FAIL = "Could not parse [%s]";
340
341 /**
342 * Converts a 4-element array into dotted decimal format.
343 */
344 private static String format(final int[] octets) {
345 final int last = octets.length - 1;
346 final StringBuilder builder = new StringBuilder();
347 for (int i = 0;; i++) {
348 builder.append(octets[i]);
349 if (i == last) {
350 return builder.toString();
351 }
352 builder.append('.');
353 }
354 }
355
356 /**
357 * Extracts the components of a dotted decimal address and pack into an integer using a regex match
358 */
359 private static int matchAddress(final Matcher matcher) {
360 int addr = 0;
361 for (int i = 1; i <= 4; ++i) {
362 final int n = rangeCheck(Integer.parseInt(matcher.group(i)), 0, 255);
363 addr |= (n & 0xff) << 8 * (4 - i);
364 }
365 return addr;
366 }
367
368 /**
369 * Checks integer boundaries. Checks if a value x is in the range [begin,end]. Returns x if it is in range, throws an exception otherwise.
370 */
371 private static int rangeCheck(final int value, final int begin, final int end) {
372 if (value >= begin && value <= end) { // (begin,end]
373 return value;
374 }
375 throw new IllegalArgumentException("Value [" + value + "] not in range [" + begin + "," + end + "]");
376 }
377
378 /**
379 * Converts a packed integer address into a 4-element array
380 */
381 private static int[] toArray4(final int val) {
382 final int[] ret = new int[4];
383 for (int j = 3; j >= 0; --j) {
384 ret[j] |= val >>> 8 * (3 - j) & 0xff;
385 }
386 return ret;
387 }
388
389 /**
390 * Converts a dotted decimal format address to a packed integer format.
391 */
392 private static int toInteger(final String address) {
393 final Matcher matcher = ADDRESS_PATTERN.matcher(address);
394 if (matcher.matches()) {
395 return matchAddress(matcher);
396 }
397 throw new IllegalArgumentException(String.format(PARSE_FAIL, address));
398 }
399
400 private final int address;
401
402 private final int broadcast;
403
404 /** Whether the broadcast/network address are included in host count */
405 private boolean inclusiveHostCount;
406
407 private final int netmask;
408
409 private final int network;
410
411 /**
412 * Constructs an instance from a CIDR-notation string, e.g. "192.168.0.1/16"
413 *
414 * @param cidrNotation A CIDR-notation string, e.g. "192.168.0.1/16"
415 * @throws IllegalArgumentException if the parameter is invalid, i.e. does not match n.n.n.n/m where n=1-3 decimal digits, m = 1-2 decimal digits in range
416 * 0-32
417 */
418 public SubnetUtils(final String cidrNotation) {
419 final Matcher matcher = CIDR_PATTERN.matcher(cidrNotation);
420
421 if (!matcher.matches()) {
422 throw new IllegalArgumentException(String.format(PARSE_FAIL, cidrNotation));
423 }
424 this.address = matchAddress(matcher);
425
426 // Create a binary netmask from the number of bits specification /x
427
428 final int trailingZeroes = NBITS - rangeCheck(Integer.parseInt(matcher.group(5)), 0, NBITS);
429
430 //
431 // An IPv4 netmask consists of 32 bits, a contiguous sequence
432 // of the specified number of ones followed by all zeros.
433 // So, it can be obtained by shifting an unsigned integer (32 bits) to the left by
434 // the number of trailing zeros which is (32 - the # bits specification).
435 // Note that there is no unsigned left shift operator, so we have to use
436 // a long to ensure that the left-most bit is shifted out correctly.
437 //
438 this.netmask = (int) (0x0FFFFFFFFL << trailingZeroes);
439
440 // Calculate base network address
441 this.network = address & netmask;
442
443 // Calculate broadcast address
444 this.broadcast = network | ~netmask;
445 }
446
447 /**
448 * Constructs an instance from a dotted decimal address and a dotted decimal mask.
449 *
450 * @param address An IP address, e.g. "192.168.0.1"
451 * @param mask A dotted decimal netmask e.g. "255.255.0.0"
452 * @throws IllegalArgumentException if the address or mask is invalid, i.e. does not match n.n.n.n where n=1-3 decimal digits and the mask is not all zeros
453 */
454 public SubnetUtils(final String address, final String mask) {
455 this.address = toInteger(address);
456 this.netmask = toInteger(mask);
457
458 if ((this.netmask & -this.netmask) - 1 != ~this.netmask) {
459 throw new IllegalArgumentException(String.format(PARSE_FAIL, mask));
460 }
461
462 // Calculate base network address
463 this.network = this.address & this.netmask;
464
465 // Calculate broadcast address
466 this.broadcast = this.network | ~this.netmask;
467 }
468
469 /**
470 * Gets a {@link SubnetInfo} instance that contains subnet-specific statistics
471 *
472 * @return new instance
473 */
474 public final SubnetInfo getInfo() {
475 return new SubnetInfo();
476 }
477
478 /**
479 * Gets the next subnet for this instance.
480 *
481 * @return the next subnet for this instance.
482 */
483 public SubnetUtils getNext() {
484 return new SubnetUtils(getInfo().getNextAddress(), getInfo().getNetmask());
485 }
486
487 /**
488 * Gets the previous subnet for this instance.
489 *
490 * @return the next previous for this instance.
491 */
492 public SubnetUtils getPrevious() {
493 return new SubnetUtils(getInfo().getPreviousAddress(), getInfo().getNetmask());
494 }
495
496 /**
497 * Tests if the return value of {@link SubnetInfo#getAddressCount()} includes the network and broadcast addresses.
498 *
499 * @return true if the host count includes the network and broadcast addresses
500 * @since 2.2
501 */
502 public boolean isInclusiveHostCount() {
503 return inclusiveHostCount;
504 }
505
506 /**
507 * Sets to {@code true} if you want the return value of {@link SubnetInfo#getAddressCount()} to include the network and broadcast addresses. This also
508 * applies to {@link SubnetInfo#isInRange(int)}
509 *
510 * @param inclusiveHostCount true if network and broadcast addresses are to be included
511 * @since 2.2
512 */
513 public void setInclusiveHostCount(final boolean inclusiveHostCount) {
514 this.inclusiveHostCount = inclusiveHostCount;
515 }
516
517 /**
518 * Converts this instance to a debug String.
519 *
520 * @return {@code this} instance to a debug String.
521 * @since 3.11.0
522 */
523 @Override
524 public String toString() {
525 return getInfo().toString();
526 }
527 }