001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      https://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.net.util;
018
019import java.util.Iterator;
020import java.util.regex.Matcher;
021import java.util.regex.Pattern;
022import java.util.stream.Stream;
023import java.util.stream.StreamSupport;
024
025/**
026 * Performs subnet calculations given a network address and a subnet mask.
027 *
028 * @see "http://www.faqs.org/rfcs/rfc1519.html"
029 * @since 2.0
030 */
031public class SubnetUtils {
032
033    /**
034     * Allows an object to be the target of the "for-each loop" statement for a SubnetInfo.
035     */
036    private static final class SubnetAddressStringIterable implements Iterable<String> {
037
038        private final SubnetInfo subnetInfo;
039
040        /**
041         * Constructs a new instance.
042         *
043         * @param subnetInfo the SubnetInfo to iterate.
044         */
045        private SubnetAddressStringIterable(final SubnetInfo subnetInfo) {
046            this.subnetInfo = subnetInfo;
047        }
048
049        @Override
050        public Iterator<String> iterator() {
051            return new SubnetAddressStringIterator(subnetInfo);
052        }
053    }
054
055    /**
056     * Iterates over a SubnetInfo.
057     */
058    private static final class SubnetAddressStringIterator implements Iterator<String> {
059
060        private int currentAddress;
061
062        private final SubnetInfo subnetInfo;
063
064        /**
065         * Constructs a new instance.
066         *
067         * @param subnetInfo the SubnetInfo to iterate.
068         */
069        private SubnetAddressStringIterator(final SubnetInfo subnetInfo) {
070            this.subnetInfo = subnetInfo;
071            currentAddress = subnetInfo.low();
072        }
073
074        @Override
075        public boolean hasNext() {
076            return subnetInfo.getAddressCountLong() > 0 && currentAddress <= subnetInfo.high();
077        }
078
079        @Override
080        public String next() {
081            return format(toArray4(currentAddress++));
082        }
083    }
084
085    /**
086     * Contains subnet summary information.
087     */
088    public final class SubnetInfo {
089
090        /** Mask to convert unsigned int to a long (i.e. keep 32 bits). */
091        private static final long UNSIGNED_INT_MASK = 0x0FFFFFFFFL;
092
093        private SubnetInfo() {
094        }
095
096        /**
097         * Converts a dotted decimal format address to a packed integer format.
098         *
099         * @param address a dotted decimal format address.
100         * @return packed integer formatted int.
101         */
102        public int asInteger(final String address) {
103            return toInteger(address);
104        }
105
106        private long broadcastLong() {
107            return broadcast & UNSIGNED_INT_MASK;
108        }
109
110        /**
111         * Gets this instance's address into a dotted decimal String.
112         *
113         * @return a dotted decimal String.
114         */
115        public String getAddress() {
116            return format(toArray4(address));
117        }
118
119        /**
120         * Gets the count of available addresses. Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false.
121         *
122         * @return the count of addresses, may be zero.
123         * @throws RuntimeException if the correct count is greater than {@code Integer.MAX_VALUE}
124         * @deprecated (3.4) use {@link #getAddressCountLong()} instead
125         */
126        @Deprecated
127        public int getAddressCount() {
128            final long countLong = getAddressCountLong();
129            if (countLong > Integer.MAX_VALUE) {
130                throw new IllegalStateException("Count is larger than an integer: " + countLong);
131            }
132            // Cannot be negative here
133            return (int) countLong;
134        }
135
136        /**
137         * Gets the count of available addresses. Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false.
138         *
139         * @return the count of addresses, may be zero.
140         * @since 3.4
141         */
142        public long getAddressCountLong() {
143            final long b = broadcastLong();
144            final long n = networkLong();
145            final long count = b - n + (isInclusiveHostCount() ? 1 : -1);
146            return count < 0 ? 0 : count;
147        }
148
149        /**
150         * Gets all addresses in this subnet, the return array could be huge.
151         * <p>
152         * For large ranges, you can iterate or stream over the addresses instead using {@link #iterableAddressStrings()} or {@link #streamAddressStrings()}.
153         * </p>
154         *
155         * @return all addresses in this subnet.
156         * @see #iterableAddressStrings()
157         * @see #streamAddressStrings()
158         */
159        public String[] getAllAddresses() {
160            final int ct = getAddressCount();
161            final String[] addresses = new String[ct];
162            if (ct == 0) {
163                return addresses;
164            }
165            final int high = high();
166            for (int add = low(), j = 0; add <= high; ++add, ++j) {
167                addresses[j] = format(toArray4(add));
168            }
169            return addresses;
170        }
171
172        /**
173         * Gets the broadcast address for this subnet.
174         *
175         * @return the broadcast address for this subnet.
176         */
177        public String getBroadcastAddress() {
178            return format(toArray4(broadcast));
179        }
180
181        /**
182         * Gets the CIDR signature for this subnet.
183         *
184         * @return the CIDR signature for this subnet.
185         */
186        public String getCidrSignature() {
187            return format(toArray4(address)) + "/" + Integer.bitCount(netmask);
188        }
189
190        /**
191         * Gets the high address as a dotted IP address. Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false.
192         *
193         * @return the IP address in dotted format, may be "0.0.0.0" if there is no valid address
194         */
195        public String getHighAddress() {
196            return format(toArray4(high()));
197        }
198
199        /**
200         * Gets the low address as a dotted IP address. Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false.
201         *
202         * @return the IP address in dotted format, may be "0.0.0.0" if there is no valid address
203         */
204        public String getLowAddress() {
205            return format(toArray4(low()));
206        }
207
208        /**
209         * Gets the network mask for this subnet.
210         *
211         * @return the network mask for this subnet.
212         */
213        public String getNetmask() {
214            return format(toArray4(netmask));
215        }
216
217        /**
218         * Gets the network address for this subnet.
219         *
220         * @return the network address for this subnet.
221         */
222        public String getNetworkAddress() {
223            return format(toArray4(network));
224        }
225
226        /**
227         * Gets the next address for this subnet.
228         *
229         * @return the next address for this subnet.
230         */
231        public String getNextAddress() {
232            return format(toArray4(address + 1));
233        }
234
235        /**
236         * Gets the previous address for this subnet.
237         *
238         * @return the previous address for this subnet.
239         */
240        public String getPreviousAddress() {
241            return format(toArray4(address - 1));
242        }
243
244        private int high() {
245            return isInclusiveHostCount() ? broadcast : broadcastLong() - networkLong() > 1 ? broadcast - 1 : 0;
246        }
247
248        /**
249         * Tests if the parameter {@code address} is in the range of usable endpoint addresses for this subnet. This excludes the network and broadcast
250         * addresses by default. Use {@link SubnetUtils#setInclusiveHostCount(boolean)} to change this.
251         *
252         * @param address the address to check
253         * @return true if it is in range
254         * @since 3.4 (made public)
255         */
256        public boolean isInRange(final int address) {
257            if (address == 0) { // cannot ever be in range; rejecting now avoids problems with CIDR/31,32
258                return false;
259            }
260            final long addLong = address & UNSIGNED_INT_MASK;
261            final long lowLong = low() & UNSIGNED_INT_MASK;
262            final long highLong = high() & UNSIGNED_INT_MASK;
263            return addLong >= lowLong && addLong <= highLong;
264        }
265
266        /**
267         * Tests if the parameter {@code address} is in the range of usable endpoint addresses for this subnet. This excludes the network and broadcast
268         * addresses. Use {@link SubnetUtils#setInclusiveHostCount(boolean)} to change this.
269         *
270         * @param address A dot-delimited IPv4 address, e.g. "192.168.0.1"
271         * @return True if in range, false otherwise
272         */
273        public boolean isInRange(final String address) {
274            return isInRange(toInteger(address));
275        }
276
277        /**
278         * Creates a new Iterable of address Strings.
279         *
280         * @return a new Iterable of address Strings
281         * @see #getAllAddresses()
282         * @see #streamAddressStrings()
283         * @since 3.12.0
284         */
285        public Iterable<String> iterableAddressStrings() {
286            return new SubnetAddressStringIterable(this);
287        }
288
289        private int low() {
290            return isInclusiveHostCount() ? network : broadcastLong() - networkLong() > 1 ? network + 1 : 0;
291        }
292
293        /** Long versions of the values (as unsigned int) which are more suitable for range checking. */
294        private long networkLong() {
295            return network & UNSIGNED_INT_MASK;
296        }
297
298        /**
299         * Creates a new Stream of address Strings.
300         *
301         * @return a new Stream of address Strings.
302         * @see #getAllAddresses()
303         * @see #iterableAddressStrings()
304         * @since 3.12.0
305         */
306        public Stream<String> streamAddressStrings() {
307            return StreamSupport.stream(iterableAddressStrings().spliterator(), false);
308        }
309
310        /**
311         * {@inheritDoc}
312         *
313         * @since 2.2
314         */
315        @Override
316        public String toString() {
317            final StringBuilder buf = new StringBuilder();
318            // @formatter:off
319            buf.append("CIDR Signature:\t[").append(getCidrSignature()).append("]\n")
320                .append("  Netmask: [").append(getNetmask()).append("]\n")
321                .append("  Network: [").append(getNetworkAddress()).append("]\n")
322                .append("  Broadcast: [").append(getBroadcastAddress()).append("]\n")
323                .append("  First address: [").append(getLowAddress()).append("]\n")
324                .append("  Last address: [").append(getHighAddress()).append("]\n")
325                .append("  Address Count: [").append(getAddressCountLong()).append("]\n");
326            // @formatter:on
327            return buf.toString();
328        }
329    }
330
331    private static final String IP_ADDRESS = "(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})";
332
333    private static final String SLASH_FORMAT = IP_ADDRESS + "/(\\d{1,2})"; // 0 -> 32
334
335    private static final Pattern ADDRESS_PATTERN = Pattern.compile(IP_ADDRESS);
336    private static final Pattern CIDR_PATTERN = Pattern.compile(SLASH_FORMAT);
337    private static final int NBITS = 32;
338    private static final String PARSE_FAIL = "Could not parse [%s]";
339
340    /**
341     * Converts a 4-element array into dotted decimal format.
342     */
343    private static String format(final int[] octets) {
344        final int last = octets.length - 1;
345        final StringBuilder builder = new StringBuilder();
346        for (int i = 0;; i++) {
347            builder.append(octets[i]);
348            if (i == last) {
349                return builder.toString();
350            }
351            builder.append('.');
352        }
353    }
354    /**
355     * Extracts the components of a dotted decimal address and pack into an integer using a regex match
356     */
357    private static int matchAddress(final Matcher matcher) {
358        int addr = 0;
359        for (int i = 1; i <= 4; ++i) {
360            final int n = rangeCheck(Integer.parseInt(matcher.group(i)), 0, 255);
361            addr |= (n & 0xff) << 8 * (4 - i);
362        }
363        return addr;
364    }
365
366    /**
367     * 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.
368     */
369    private static int rangeCheck(final int value, final int begin, final int end) {
370        if (value >= begin && value <= end) { // (begin,end]
371            return value;
372        }
373        throw new IllegalArgumentException("Value [" + value + "] not in range [" + begin + "," + end + "]");
374    }
375
376    /**
377     * Converts a packed integer address into a 4-element array
378     */
379    private static int[] toArray4(final int val) {
380        final int[] ret = new int[4];
381        for (int j = 3; j >= 0; --j) {
382            ret[j] |= val >>> 8 * (3 - j) & 0xff;
383        }
384        return ret;
385    }
386
387    /**
388     * Converts a dotted decimal format address to a packed integer format.
389     */
390    private static int toInteger(final String address) {
391        final Matcher matcher = ADDRESS_PATTERN.matcher(address);
392        if (matcher.matches()) {
393            return matchAddress(matcher);
394        }
395        throw new IllegalArgumentException(String.format(PARSE_FAIL, address));
396    }
397
398    private final int address;
399
400    private final int broadcast;
401
402    /** Whether the broadcast/network address are included in host count */
403    private boolean inclusiveHostCount;
404
405    private final int netmask;
406
407    private final int network;
408
409    /**
410     * Constructs an instance from a CIDR-notation string, e.g. "192.168.0.1/16"
411     *
412     * @param cidrNotation A CIDR-notation string, e.g. "192.168.0.1/16"
413     * @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
414     *                                  0-32
415     */
416    public SubnetUtils(final String cidrNotation) {
417        final Matcher matcher = CIDR_PATTERN.matcher(cidrNotation);
418
419        if (!matcher.matches()) {
420            throw new IllegalArgumentException(String.format(PARSE_FAIL, cidrNotation));
421        }
422        this.address = matchAddress(matcher);
423
424        // Create a binary netmask from the number of bits specification /x
425
426        final int trailingZeroes = NBITS - rangeCheck(Integer.parseInt(matcher.group(5)), 0, NBITS);
427
428        //
429        // An IPv4 netmask consists of 32 bits, a contiguous sequence
430        // of the specified number of ones followed by all zeros.
431        // So, it can be obtained by shifting an unsigned integer (32 bits) to the left by
432        // the number of trailing zeros which is (32 - the # bits specification).
433        // Note that there is no unsigned left shift operator, so we have to use
434        // a long to ensure that the left-most bit is shifted out correctly.
435        //
436        this.netmask = (int) (0x0FFFFFFFFL << trailingZeroes);
437
438        // Calculate base network address
439        this.network = address & netmask;
440
441        // Calculate broadcast address
442        this.broadcast = network | ~netmask;
443    }
444
445    /**
446     * Constructs an instance from a dotted decimal address and a dotted decimal mask.
447     *
448     * @param address An IP address, e.g. "192.168.0.1"
449     * @param mask    A dotted decimal netmask e.g. "255.255.0.0"
450     * @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
451     */
452    public SubnetUtils(final String address, final String mask) {
453        this.address = toInteger(address);
454        this.netmask = toInteger(mask);
455
456        if ((this.netmask & -this.netmask) - 1 != ~this.netmask) {
457            throw new IllegalArgumentException(String.format(PARSE_FAIL, mask));
458        }
459
460        // Calculate base network address
461        this.network = this.address & this.netmask;
462
463        // Calculate broadcast address
464        this.broadcast = this.network | ~this.netmask;
465    }
466
467    /**
468     * Gets a {@link SubnetInfo} instance that contains subnet-specific statistics
469     *
470     * @return new instance
471     */
472    public final SubnetInfo getInfo() {
473        return new SubnetInfo();
474    }
475
476    /**
477     * Gets the next subnet for this instance.
478     *
479     * @return the next subnet for this instance.
480     */
481    public SubnetUtils getNext() {
482        return new SubnetUtils(getInfo().getNextAddress(), getInfo().getNetmask());
483    }
484
485    /**
486     * Gets the previous subnet for this instance.
487     *
488     * @return the next previous for this instance.
489     */
490    public SubnetUtils getPrevious() {
491        return new SubnetUtils(getInfo().getPreviousAddress(), getInfo().getNetmask());
492    }
493
494    /**
495     * Tests if the return value of {@link SubnetInfo#getAddressCount()} includes the network and broadcast addresses.
496     *
497     * @return true if the host count includes the network and broadcast addresses
498     * @since 2.2
499     */
500    public boolean isInclusiveHostCount() {
501        return inclusiveHostCount;
502    }
503
504    /**
505     * Sets to {@code true} if you want the return value of {@link SubnetInfo#getAddressCount()} to include the network and broadcast addresses. This also
506     * applies to {@link SubnetInfo#isInRange(int)}
507     *
508     * @param inclusiveHostCount true if network and broadcast addresses are to be included
509     * @since 2.2
510     */
511    public void setInclusiveHostCount(final boolean inclusiveHostCount) {
512        this.inclusiveHostCount = inclusiveHostCount;
513    }
514
515    /**
516     * Converts this instance to a debug String.
517     *
518     * @return this instance to a debug String.
519     * @since 3.11.0
520     */
521    @Override
522    public String toString() {
523        return getInfo().toString();
524    }
525}