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 */
017 package org.apache.commons.net.util;
018
019 import java.util.regex.Matcher;
020 import java.util.regex.Pattern;
021
022 /**
023 * A class that performs some subnet calculations given a network address and a subnet mask.
024 * @see "http://www.faqs.org/rfcs/rfc1519.html"
025 * @author <rwinston@apache.org>
026 * @since 2.0
027 */
028 public class SubnetUtils {
029
030 private static final String IP_ADDRESS = "(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})";
031 private static final String SLASH_FORMAT = IP_ADDRESS + "/(\\d{1,3})";
032 private static final Pattern addressPattern = Pattern.compile(IP_ADDRESS);
033 private static final Pattern cidrPattern = Pattern.compile(SLASH_FORMAT);
034 private static final int NBITS = 32;
035
036 private int netmask = 0;
037 private int address = 0;
038 private int network = 0;
039 private int broadcast = 0;
040
041 /** Whether the broadcast/network address are included in host count */
042 private boolean inclusiveHostCount = false;
043
044
045 /**
046 * Constructor that takes a CIDR-notation string, e.g. "192.168.0.1/16"
047 * @param cidrNotation A CIDR-notation string, e.g. "192.168.0.1/16"
048 * @throws IllegalArgumentException if the parameter is invalid,
049 * i.e. does not match n.n.n.n/m where n=1-3 decimal digits, m = 1-3 decimal digits in range 1-32
050 */
051 public SubnetUtils(String cidrNotation) {
052 calculate(cidrNotation);
053 }
054
055 /**
056 * Constructor that takes a dotted decimal address and a dotted decimal mask.
057 * @param address An IP address, e.g. "192.168.0.1"
058 * @param mask A dotted decimal netmask e.g. "255.255.0.0"
059 * @throws IllegalArgumentException if the address or mask is invalid,
060 * i.e. does not match n.n.n.n where n=1-3 decimal digits and the mask is not all zeros
061 */
062 public SubnetUtils(String address, String mask) {
063 calculate(toCidrNotation(address, mask));
064 }
065
066
067 /**
068 * Returns <code>true</code> if the return value of {@link SubnetInfo#getAddressCount()}
069 * includes the network address and broadcast addresses.
070 * @since 2.2
071 */
072 public boolean isInclusiveHostCount() {
073 return inclusiveHostCount;
074 }
075
076 /**
077 * Set to <code>true</code> if you want the return value of {@link SubnetInfo#getAddressCount()}
078 * to include the network and broadcast addresses.
079 * @param inclusiveHostCount
080 * @since 2.2
081 */
082 public void setInclusiveHostCount(boolean inclusiveHostCount) {
083 this.inclusiveHostCount = inclusiveHostCount;
084 }
085
086
087
088 /**
089 * Convenience container for subnet summary information.
090 *
091 */
092 public final class SubnetInfo {
093 private SubnetInfo() {}
094
095 private int netmask() { return netmask; }
096 private int network() { return network; }
097 private int address() { return address; }
098 private int broadcast() { return broadcast; }
099 private int low() { return network() + (isInclusiveHostCount() ? 0 : 1); }
100 private int high() { return broadcast() - (isInclusiveHostCount() ? 0 : 1); }
101
102 /**
103 * Returns true if the parameter <code>address</code> is in the
104 * range of usable endpoint addresses for this subnet. This excludes the
105 * network and broadcast adresses.
106 * @param address A dot-delimited IPv4 address, e.g. "192.168.0.1"
107 * @return True if in range, false otherwise
108 */
109 public boolean isInRange(String address) { return isInRange(toInteger(address)); }
110
111 private boolean isInRange(int address) {
112 int diff = address-low();
113 return (diff >= 0 && (diff <= (high()-low())));
114 }
115
116 public String getBroadcastAddress() { return format(toArray(broadcast())); }
117 public String getNetworkAddress() { return format(toArray(network())); }
118 public String getNetmask() { return format(toArray(netmask())); }
119 public String getAddress() { return format(toArray(address())); }
120 public String getLowAddress() { return format(toArray(low())); }
121 public String getHighAddress() { return format(toArray(high())); }
122 public int getAddressCount() { return (broadcast() - low() + (isInclusiveHostCount() ? 1 : 0)); }
123
124 public int asInteger(String address) { return toInteger(address); }
125
126 public String getCidrSignature() {
127 return toCidrNotation(
128 format(toArray(address())),
129 format(toArray(netmask()))
130 );
131 }
132
133 public String[] getAllAddresses() {
134 String[] addresses = new String[getAddressCount()];
135 for (int add = low(), j=0; add <= high(); ++add, ++j) {
136 addresses[j] = format(toArray(add));
137 }
138 return addresses;
139 }
140
141 /**
142 * {@inheritDoc}
143 * @since 2.2
144 */
145 @Override
146 public String toString() {
147 final StringBuilder buf = new StringBuilder();
148 buf.append("CIDR Signature:\t[").append(getCidrSignature()).append("]")
149 .append(" Netmask: [").append(getNetmask()).append("]\n")
150 .append("Network:\t[").append(getNetworkAddress()).append("]\n")
151 .append("Broadcast:\t[").append(getBroadcastAddress()).append("]\n")
152 .append("First Address:\t[").append(getLowAddress()).append("]\n")
153 .append("Last Address:\t[").append(getHighAddress()).append("]\n")
154 .append("# Addresses:\t[").append(getAddressCount()).append("]\n");
155 return buf.toString();
156 }
157 }
158
159 /**
160 * Return a {@link SubnetInfo} instance that contains subnet-specific statistics
161 * @return new instance
162 */
163 public final SubnetInfo getInfo() { return new SubnetInfo(); }
164
165 /*
166 * Initialize the internal fields from the supplied CIDR mask
167 */
168 private void calculate(String mask) {
169 Matcher matcher = cidrPattern.matcher(mask);
170
171 if (matcher.matches()) {
172 address = matchAddress(matcher);
173
174 /* Create a binary netmask from the number of bits specification /x */
175 int cidrPart = rangeCheck(Integer.parseInt(matcher.group(5)), -1, NBITS);
176 for (int j = 0; j < cidrPart; ++j) {
177 netmask |= (1 << 31-j);
178 }
179
180 rangeCheck(pop(netmask),0, NBITS);
181
182 /* Calculate base network address */
183 network = (address & netmask);
184
185 /* Calculate broadcast address */
186 broadcast = network | ~(netmask);
187 }
188 else
189 throw new IllegalArgumentException("Could not parse [" + mask + "]");
190 }
191
192 /*
193 * Convert a dotted decimal format address to a packed integer format
194 */
195 private int toInteger(String address) {
196 Matcher matcher = addressPattern.matcher(address);
197 if (matcher.matches()) {
198 return matchAddress(matcher);
199 }
200 else
201 throw new IllegalArgumentException("Could not parse [" + address + "]");
202 }
203
204 /*
205 * Convenience method to extract the components of a dotted decimal address and
206 * pack into an integer using a regex match
207 */
208 private int matchAddress(Matcher matcher) {
209 int addr = 0;
210 for (int i = 1; i <= 4; ++i) {
211 int n = (rangeCheck(Integer.parseInt(matcher.group(i)), -1, 255));
212 addr |= ((n & 0xff) << 8*(4-i));
213 }
214 return addr;
215 }
216
217 /*
218 * Convert a packed integer address into a 4-element array
219 */
220 private int[] toArray(int val) {
221 int ret[] = new int[4];
222 for (int j = 3; j >= 0; --j)
223 ret[j] |= ((val >>> 8*(3-j)) & (0xff));
224 return ret;
225 }
226
227 /*
228 * Convert a 4-element array into dotted decimal format
229 */
230 private String format(int[] octets) {
231 StringBuilder str = new StringBuilder();
232 for (int i =0; i < octets.length; ++i){
233 str.append(octets[i]);
234 if (i != octets.length - 1) {
235 str.append(".");
236 }
237 }
238 return str.toString();
239 }
240
241 /*
242 * Convenience function to check integer boundaries.
243 * Checks if a value x is in the range (begin,end].
244 * Returns x if it is in range, throws an exception otherwise.
245 */
246 private int rangeCheck(int value, int begin, int end) {
247 if (value > begin && value <= end) // (begin,end]
248 return value;
249
250 throw new IllegalArgumentException("Value [" + value + "] not in range ("+begin+","+end+"]");
251 }
252
253 /*
254 * Count the number of 1-bits in a 32-bit integer using a divide-and-conquer strategy
255 * see Hacker's Delight section 5.1
256 */
257 int pop(int x) {
258 x = x - ((x >>> 1) & 0x55555555);
259 x = (x & 0x33333333) + ((x >>> 2) & 0x33333333);
260 x = (x + (x >>> 4)) & 0x0F0F0F0F;
261 x = x + (x >>> 8);
262 x = x + (x >>> 16);
263 return x & 0x0000003F;
264 }
265
266 /* Convert two dotted decimal addresses to a single xxx.xxx.xxx.xxx/yy format
267 * by counting the 1-bit population in the mask address. (It may be better to count
268 * NBITS-#trailing zeroes for this case)
269 */
270 private String toCidrNotation(String addr, String mask) {
271 return addr + "/" + pop(toInteger(mask));
272 }
273 }