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 }