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 *      http://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.regex.Matcher;
020import java.util.regex.Pattern;
021
022/**
023 * Performs subnet calculations given a network address and a subnet mask.
024 *
025 * @see "http://www.faqs.org/rfcs/rfc1519.html"
026 * @since 2.0
027 */
028public class SubnetUtils {
029
030    /**
031     * Convenience container for subnet summary information.
032     */
033    public final class SubnetInfo {
034
035        /** Mask to convert unsigned int to a long (i.e. keep 32 bits). */
036        private static final long UNSIGNED_INT_MASK = 0x0FFFFFFFFL;
037
038        private SubnetInfo() {
039        }
040
041        public int asInteger(final String address) {
042            return toInteger(address);
043        }
044
045        private long broadcastLong() {
046            return broadcast & UNSIGNED_INT_MASK;
047        }
048
049        /**
050         * Converts a 4-element array into dotted decimal format.
051         */
052        private String format(final int[] octets) {
053            final int last = octets.length - 1;
054            final StringBuilder builder = new StringBuilder();
055            for (int i = 0;; i++) {
056                builder.append(octets[i]);
057                if (i == last) {
058                    return builder.toString();
059                }
060                builder.append('.');
061            }
062        }
063
064        public String getAddress() {
065            return format(toArray(address));
066        }
067
068        /**
069         * Gets the count of available addresses. Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false.
070         *
071         * @return the count of addresses, may be zero.
072         * @throws RuntimeException if the correct count is greater than {@code Integer.MAX_VALUE}
073         * @deprecated (3.4) use {@link #getAddressCountLong()} instead
074         */
075        @Deprecated
076        public int getAddressCount() {
077            final long countLong = getAddressCountLong();
078            if (countLong > Integer.MAX_VALUE) {
079                throw new IllegalStateException("Count is larger than an integer: " + countLong);
080            }
081            // Cannot be negative here
082            return (int) countLong;
083        }
084
085        /**
086         * Gets the count of available addresses. Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false.
087         *
088         * @return the count of addresses, may be zero.
089         * @since 3.4
090         */
091        public long getAddressCountLong() {
092            final long b = broadcastLong();
093            final long n = networkLong();
094            final long count = b - n + (isInclusiveHostCount() ? 1 : -1);
095            return count < 0 ? 0 : count;
096        }
097
098        public String[] getAllAddresses() {
099            final int ct = getAddressCount();
100            final String[] addresses = new String[ct];
101            if (ct == 0) {
102                return addresses;
103            }
104            for (int add = low(), j = 0; add <= high(); ++add, ++j) {
105                addresses[j] = format(toArray(add));
106            }
107            return addresses;
108        }
109
110        public String getBroadcastAddress() {
111            return format(toArray(broadcast));
112        }
113
114        public String getCidrSignature() {
115            return format(toArray(address)) + "/" + Integer.bitCount(netmask);
116        }
117
118        /**
119         * Gets the high address as a dotted IP address. Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false.
120         *
121         * @return the IP address in dotted format, may be "0.0.0.0" if there is no valid address
122         */
123        public String getHighAddress() {
124            return format(toArray(high()));
125        }
126
127        /**
128         * Gets the low address as a dotted IP address. Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false.
129         *
130         * @return the IP address in dotted format, may be "0.0.0.0" if there is no valid address
131         */
132        public String getLowAddress() {
133            return format(toArray(low()));
134        }
135
136        public String getNetmask() {
137            return format(toArray(netmask));
138        }
139
140        public String getNetworkAddress() {
141            return format(toArray(network));
142        }
143
144        public String getNextAddress() {
145            return format(toArray(address + 1));
146        }
147
148        public String getPreviousAddress() {
149            return format(toArray(address - 1));
150        }
151
152        private int high() {
153            return isInclusiveHostCount() ? broadcast : broadcastLong() - networkLong() > 1 ? broadcast - 1 : 0;
154        }
155
156        /**
157         * Tests if the parameter <code>address</code> is in the range of usable endpoint addresses for this subnet. This excludes the network and broadcast
158         * addresses by default. Use {@link SubnetUtils#setInclusiveHostCount(boolean)} to change this.
159         *
160         * @param address the address to check
161         * @return true if it is in range
162         * @since 3.4 (made public)
163         */
164        public boolean isInRange(final int address) {
165            if (address == 0) { // cannot ever be in range; rejecting now avoids problems with CIDR/31,32
166                return false;
167            }
168            final long addLong = address & UNSIGNED_INT_MASK;
169            final long lowLong = low() & UNSIGNED_INT_MASK;
170            final long highLong = high() & UNSIGNED_INT_MASK;
171            return addLong >= lowLong && addLong <= highLong;
172        }
173
174        /**
175         * Tests if the parameter <code>address</code> is in the range of usable endpoint addresses for this subnet. This excludes the network and broadcast
176         * addresses. Use {@link SubnetUtils#setInclusiveHostCount(boolean)} to change this.
177         *
178         * @param address A dot-delimited IPv4 address, e.g. "192.168.0.1"
179         * @return True if in range, false otherwise
180         */
181        public boolean isInRange(final String address) {
182            return isInRange(toInteger(address));
183        }
184
185        private int low() {
186            return isInclusiveHostCount() ? network : broadcastLong() - networkLong() > 1 ? network + 1 : 0;
187        }
188
189        /** Long versions of the values (as unsigned int) which are more suitable for range checking. */
190        private long networkLong() {
191            return network & UNSIGNED_INT_MASK;
192        }
193
194        /**
195         * Converts a packed integer address into a 4-element array
196         */
197        private int[] toArray(final int val) {
198            final int[] ret = new int[4];
199            for (int j = 3; j >= 0; --j) {
200                ret[j] |= val >>> 8 * (3 - j) & 0xff;
201            }
202            return ret;
203        }
204
205        /**
206         * {@inheritDoc}
207         *
208         * @since 2.2
209         */
210        @Override
211        public String toString() {
212            final StringBuilder buf = new StringBuilder();
213            // @formatter:off
214            buf.append("CIDR Signature:\t[").append(getCidrSignature()).append("]\n")
215                .append("  Netmask: [").append(getNetmask()).append("]\n")
216                .append("  Network: [").append(getNetworkAddress()).append("]\n")
217                .append("  Broadcast: [").append(getBroadcastAddress()).append("]\n")
218                .append("  First address: [").append(getLowAddress()).append("]\n")
219                .append("  Last address: [").append(getHighAddress()).append("]\n")
220                .append("  Address Count: [").append(getAddressCountLong()).append("]\n");
221            // @formatter:on
222            return buf.toString();
223        }
224    }
225
226    private static final String IP_ADDRESS = "(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})";
227    private static final String SLASH_FORMAT = IP_ADDRESS + "/(\\d{1,2})"; // 0 -> 32
228    private static final Pattern ADDRESS_PATTERN = Pattern.compile(IP_ADDRESS);
229    private static final Pattern CIDR_PATTERN = Pattern.compile(SLASH_FORMAT);
230
231    private static final int NBITS = 32;
232
233    private static final String PARSE_FAIL = "Could not parse [%s]";
234
235    /*
236     * Extracts the components of a dotted decimal address and pack into an integer using a regex match
237     */
238    private static int matchAddress(final Matcher matcher) {
239        int addr = 0;
240        for (int i = 1; i <= 4; ++i) {
241            final int n = rangeCheck(Integer.parseInt(matcher.group(i)), 0, 255);
242            addr |= (n & 0xff) << 8 * (4 - i);
243        }
244        return addr;
245    }
246
247    /*
248     * 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.
249     */
250    private static int rangeCheck(final int value, final int begin, final int end) {
251        if (value >= begin && value <= end) { // (begin,end]
252            return value;
253        }
254        throw new IllegalArgumentException("Value [" + value + "] not in range [" + begin + "," + end + "]");
255    }
256
257    /*
258     * Converts a dotted decimal format address to a packed integer format
259     */
260    private static int toInteger(final String address) {
261        final Matcher matcher = ADDRESS_PATTERN.matcher(address);
262        if (matcher.matches()) {
263            return matchAddress(matcher);
264        }
265        throw new IllegalArgumentException(String.format(PARSE_FAIL, address));
266    }
267
268    private final int netmask;
269
270    private final int address;
271
272    private final int network;
273
274    private final int broadcast;
275
276    /** Whether the broadcast/network address are included in host count */
277    private boolean inclusiveHostCount;
278
279    /**
280     * Constructs an instance from a CIDR-notation string, e.g. "192.168.0.1/16"
281     *
282     * @param cidrNotation A CIDR-notation string, e.g. "192.168.0.1/16"
283     * @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
284     *                                  0-32
285     */
286    public SubnetUtils(final String cidrNotation) {
287        final Matcher matcher = CIDR_PATTERN.matcher(cidrNotation);
288
289        if (!matcher.matches()) {
290            throw new IllegalArgumentException(String.format(PARSE_FAIL, cidrNotation));
291        }
292        this.address = matchAddress(matcher);
293
294        // Create a binary netmask from the number of bits specification /x
295
296        final int trailingZeroes = NBITS - rangeCheck(Integer.parseInt(matcher.group(5)), 0, NBITS);
297
298        //
299        // An IPv4 netmask consists of 32 bits, a contiguous sequence
300        // of the specified number of ones followed by all zeros.
301        // So, it can be obtained by shifting an unsigned integer (32 bits) to the left by
302        // the number of trailing zeros which is (32 - the # bits specification).
303        // Note that there is no unsigned left shift operator, so we have to use
304        // a long to ensure that the left-most bit is shifted out correctly.
305        //
306        this.netmask = (int) (0x0FFFFFFFFL << trailingZeroes);
307
308        // Calculate base network address
309        this.network = address & netmask;
310
311        // Calculate broadcast address
312        this.broadcast = network | ~netmask;
313    }
314
315    /**
316     * Constructs an instance from a dotted decimal address and a dotted decimal mask.
317     *
318     * @param address An IP address, e.g. "192.168.0.1"
319     * @param mask    A dotted decimal netmask e.g. "255.255.0.0"
320     * @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
321     */
322    public SubnetUtils(final String address, final String mask) {
323        this.address = toInteger(address);
324        this.netmask = toInteger(mask);
325
326        if ((this.netmask & -this.netmask) - 1 != ~this.netmask) {
327            throw new IllegalArgumentException(String.format(PARSE_FAIL, mask));
328        }
329
330        // Calculate base network address
331        this.network = this.address & this.netmask;
332
333        // Calculate broadcast address
334        this.broadcast = this.network | ~this.netmask;
335    }
336
337    /**
338     * Gets a {@link SubnetInfo} instance that contains subnet-specific statistics
339     *
340     * @return new instance
341     */
342    public final SubnetInfo getInfo() {
343        return new SubnetInfo();
344    }
345
346    public SubnetUtils getNext() {
347        return new SubnetUtils(getInfo().getNextAddress(), getInfo().getNetmask());
348    }
349
350    public SubnetUtils getPrevious() {
351        return new SubnetUtils(getInfo().getPreviousAddress(), getInfo().getNetmask());
352    }
353
354    /**
355     * Tests if the return value of {@link SubnetInfo#getAddressCount()} includes the network and broadcast addresses.
356     *
357     * @since 2.2
358     * @return true if the host count includes the network and broadcast addresses
359     */
360    public boolean isInclusiveHostCount() {
361        return inclusiveHostCount;
362    }
363
364    /**
365     * Sets to {@code true} if you want the return value of {@link SubnetInfo#getAddressCount()} to include the network and broadcast addresses. This also
366     * applies to {@link SubnetInfo#isInRange(int)}
367     *
368     * @param inclusiveHostCount true if network and broadcast addresses are to be included
369     * @since 2.2
370     */
371    public void setInclusiveHostCount(final boolean inclusiveHostCount) {
372        this.inclusiveHostCount = inclusiveHostCount;
373    }
374
375    /**
376     * Converts this instance to a debug String.
377     *
378     * @return this instance to a debug String.
379     * @since 3.11.0
380     */
381    @Override
382    public String toString() {
383        return getInfo().toString();
384    }
385}