    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 some 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 RuntimeException("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</code> 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}