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
100 private int low() {
101 return (isInclusiveHostCount() ? network() :
102 broadcast() - network() > 1 ? network() + 1 : 0);
103 }
104
105 private int high() {
106 return (isInclusiveHostCount() ? broadcast() :
107 broadcast() - network() > 1 ? broadcast() -1 : 0);
108 }
109
110 /**
111 * Returns true if the parameter <code>address</code> is in the
112 * range of usable endpoint addresses for this subnet. This excludes the
113 * network and broadcast adresses.
114 * @param address A dot-delimited IPv4 address, e.g. "192.168.0.1"
115 * @return True if in range, false otherwise
116 */
117 public boolean isInRange(String address) {
118 return isInRange(toInteger(address));
119 }
120
121 private boolean isInRange(int address) {
122 int diff = address - low();
123 return (diff >= 0 && (diff <= (high() - low())));
124 }
125
126 public String getBroadcastAddress() {
127 return format(toArray(broadcast()));
128 }
129
130 public String getNetworkAddress() {
131 return format(toArray(network()));
132 }
133
134 public String getNetmask() {
135 return format(toArray(netmask()));
136 }
137
138 public String getAddress() {
139 return format(toArray(address()));
140 }
141
142 /**
143 * Return the low address as a dotted IP address.
144 * Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false.
145 *
146 * @return the IP address in dotted format, may be "0.0.0.0" if there is no valid address
147 */
148 public String getLowAddress() {
149 return format(toArray(low()));
150 }
151
152 /**
153 * Return the high address as a dotted IP address.
154 * Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false.
155 *
156 * @return the IP address in dotted format, may be "0.0.0.0" if there is no valid address
157 */
158 public String getHighAddress() {
159 return format(toArray(high()));
160 }
161
162 /**
163 * Get the count of available addresses.
164 * Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false.
165 * @return the count of addresses, may be zero.
166 */
167 public int getAddressCount() {
168 int count = broadcast() - network() + (isInclusiveHostCount() ? 1 : -1);
169 return count < 0 ? 0 : count;
170 }
171
172 public int asInteger(String address) {
173 return toInteger(address);
174 }
175
176 public String getCidrSignature() {
177 return toCidrNotation(
178 format(toArray(address())),
179 format(toArray(netmask()))
180 );
181 }
182
183 public String[] getAllAddresses() {
184 int ct = getAddressCount();
185 String[] addresses = new String[ct];
186 if (ct == 0) {
187 return addresses;
188 }
189 for (int add = low(), j=0; add <= high(); ++add, ++j) {
190 addresses[j] = format(toArray(add));
191 }
192 return addresses;
193 }
194
195 /**
196 * {@inheritDoc}
197 * @since 2.2
198 */
199 @Override
200 public String toString() {
201 final StringBuilder buf = new StringBuilder();
202 buf.append("CIDR Signature:\t[").append(getCidrSignature()).append("]")
203 .append(" Netmask: [").append(getNetmask()).append("]\n")
204 .append("Network:\t[").append(getNetworkAddress()).append("]\n")
205 .append("Broadcast:\t[").append(getBroadcastAddress()).append("]\n")
206 .append("First Address:\t[").append(getLowAddress()).append("]\n")
207 .append("Last Address:\t[").append(getHighAddress()).append("]\n")
208 .append("# Addresses:\t[").append(getAddressCount()).append("]\n");
209 return buf.toString();
210 }
211 }
212
213 /**
214 * Return a {@link SubnetInfo} instance that contains subnet-specific statistics
215 * @return new instance
216 */
217 public final SubnetInfo getInfo() { return new SubnetInfo(); }
218
219 /*
220 * Initialize the internal fields from the supplied CIDR mask
221 */
222 private void calculate(String mask) {
223 Matcher matcher = cidrPattern.matcher(mask);
224
225 if (matcher.matches()) {
226 address = matchAddress(matcher);
227
228 /* Create a binary netmask from the number of bits specification /x */
229 int cidrPart = rangeCheck(Integer.parseInt(matcher.group(5)), 0, NBITS);
230 for (int j = 0; j < cidrPart; ++j) {
231 netmask |= (1 << 31-j);
232 }
233
234 /* Calculate base network address */
235 network = (address & netmask);
236
237 /* Calculate broadcast address */
238 broadcast = network | ~(netmask);
239 } else {
240 throw new IllegalArgumentException("Could not parse [" + mask + "]");
241 }
242 }
243
244 /*
245 * Convert a dotted decimal format address to a packed integer format
246 */
247 private int toInteger(String address) {
248 Matcher matcher = addressPattern.matcher(address);
249 if (matcher.matches()) {
250 return matchAddress(matcher);
251 } else {
252 throw new IllegalArgumentException("Could not parse [" + address + "]");
253 }
254 }
255
256 /*
257 * Convenience method to extract the components of a dotted decimal address and
258 * pack into an integer using a regex match
259 */
260 private int matchAddress(Matcher matcher) {
261 int addr = 0;
262 for (int i = 1; i <= 4; ++i) {
263 int n = (rangeCheck(Integer.parseInt(matcher.group(i)), -1, 255));
264 addr |= ((n & 0xff) << 8*(4-i));
265 }
266 return addr;
267 }
268
269 /*
270 * Convert a packed integer address into a 4-element array
271 */
272 private int[] toArray(int val) {
273 int ret[] = new int[4];
274 for (int j = 3; j >= 0; --j) {
275 ret[j] |= ((val >>> 8*(3-j)) & (0xff));
276 }
277 return ret;
278 }
279
280 /*
281 * Convert a 4-element array into dotted decimal format
282 */
283 private String format(int[] octets) {
284 StringBuilder str = new StringBuilder();
285 for (int i =0; i < octets.length; ++i){
286 str.append(octets[i]);
287 if (i != octets.length - 1) {
288 str.append(".");
289 }
290 }
291 return str.toString();
292 }
293
294 /*
295 * Convenience function to check integer boundaries.
296 * Checks if a value x is in the range (begin,end].
297 * Returns x if it is in range, throws an exception otherwise.
298 */
299 private int rangeCheck(int value, int begin, int end) {
300 if (value > begin && value <= end) { // (begin,end]
301 return value;
302 }
303
304 throw new IllegalArgumentException("Value [" + value + "] not in range ("+begin+","+end+"]");
305 }
306
307 /*
308 * Count the number of 1-bits in a 32-bit integer using a divide-and-conquer strategy
309 * see Hacker's Delight section 5.1
310 */
311 int pop(int x) {
312 x = x - ((x >>> 1) & 0x55555555);
313 x = (x & 0x33333333) + ((x >>> 2) & 0x33333333);
314 x = (x + (x >>> 4)) & 0x0F0F0F0F;
315 x = x + (x >>> 8);
316 x = x + (x >>> 16);
317 return x & 0x0000003F;
318 }
319
320 /* Convert two dotted decimal addresses to a single xxx.xxx.xxx.xxx/yy format
321 * by counting the 1-bit population in the mask address. (It may be better to count
322 * NBITS-#trailing zeroes for this case)
323 */
324 private String toCidrNotation(String addr, String mask) {
325 return addr + "/" + pop(toInteger(mask));
326 }
327 }