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 * 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 */ 028public 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 private int high() { 105 return (isInclusiveHostCount() ? broadcast() : 106 broadcast() - network() > 1 ? broadcast() -1 : 0); 107 } 108 109 /** 110 * Returns true if the parameter <code>address</code> is in the 111 * range of usable endpoint addresses for this subnet. This excludes the 112 * network and broadcast adresses. 113 * @param address A dot-delimited IPv4 address, e.g. "192.168.0.1" 114 * @return True if in range, false otherwise 115 */ 116 public boolean isInRange(String address) { return isInRange(toInteger(address)); } 117 118 private boolean isInRange(int address) { 119 int diff = address-low(); 120 return (diff >= 0 && (diff <= (high()-low()))); 121 } 122 123 public String getBroadcastAddress() { return format(toArray(broadcast())); } 124 public String getNetworkAddress() { return format(toArray(network())); } 125 public String getNetmask() { return format(toArray(netmask())); } 126 public String getAddress() { return format(toArray(address())); } 127 128 /** 129 * Return the low address as a dotted IP address. 130 * Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false. 131 * 132 * @return the IP address in dotted format, may be "0.0.0.0" if there is no valid address 133 */ 134 public String getLowAddress() { return format(toArray(low())); } 135 136 /** 137 * Return the high address as a dotted IP address. 138 * Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false. 139 * 140 * @return the IP address in dotted format, may be "0.0.0.0" if there is no valid address 141 */ 142 public String getHighAddress() { return format(toArray(high())); } 143 144 /** 145 * Get the count of available addresses. 146 * Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false. 147 * @return the count of addresses, may be zero. 148 */ 149 public int getAddressCount() { 150 int count = broadcast() - network() + (isInclusiveHostCount() ? 1 : -1); 151 return count < 0 ? 0 : count; 152 } 153 154 public int asInteger(String address) { return toInteger(address); } 155 156 public String getCidrSignature() { 157 return toCidrNotation( 158 format(toArray(address())), 159 format(toArray(netmask())) 160 ); 161 } 162 163 public String[] getAllAddresses() { 164 int ct = getAddressCount(); 165 String[] addresses = new String[ct]; 166 if (ct == 0) { 167 return addresses; 168 } 169 for (int add = low(), j=0; add <= high(); ++add, ++j) { 170 addresses[j] = format(toArray(add)); 171 } 172 return addresses; 173 } 174 175 /** 176 * {@inheritDoc} 177 * @since 2.2 178 */ 179 @Override 180 public String toString() { 181 final StringBuilder buf = new StringBuilder(); 182 buf.append("CIDR Signature:\t[").append(getCidrSignature()).append("]") 183 .append(" Netmask: [").append(getNetmask()).append("]\n") 184 .append("Network:\t[").append(getNetworkAddress()).append("]\n") 185 .append("Broadcast:\t[").append(getBroadcastAddress()).append("]\n") 186 .append("First Address:\t[").append(getLowAddress()).append("]\n") 187 .append("Last Address:\t[").append(getHighAddress()).append("]\n") 188 .append("# Addresses:\t[").append(getAddressCount()).append("]\n"); 189 return buf.toString(); 190 } 191 } 192 193 /** 194 * Return a {@link SubnetInfo} instance that contains subnet-specific statistics 195 * @return new instance 196 */ 197 public final SubnetInfo getInfo() { return new SubnetInfo(); } 198 199 /* 200 * Initialize the internal fields from the supplied CIDR mask 201 */ 202 private void calculate(String mask) { 203 Matcher matcher = cidrPattern.matcher(mask); 204 205 if (matcher.matches()) { 206 address = matchAddress(matcher); 207 208 /* Create a binary netmask from the number of bits specification /x */ 209 int cidrPart = rangeCheck(Integer.parseInt(matcher.group(5)), 0, NBITS); 210 for (int j = 0; j < cidrPart; ++j) { 211 netmask |= (1 << 31-j); 212 } 213 214 /* Calculate base network address */ 215 network = (address & netmask); 216 217 /* Calculate broadcast address */ 218 broadcast = network | ~(netmask); 219 } else { 220 throw new IllegalArgumentException("Could not parse [" + mask + "]"); 221 } 222 } 223 224 /* 225 * Convert a dotted decimal format address to a packed integer format 226 */ 227 private int toInteger(String address) { 228 Matcher matcher = addressPattern.matcher(address); 229 if (matcher.matches()) { 230 return matchAddress(matcher); 231 } else { 232 throw new IllegalArgumentException("Could not parse [" + address + "]"); 233 } 234 } 235 236 /* 237 * Convenience method to extract the components of a dotted decimal address and 238 * pack into an integer using a regex match 239 */ 240 private int matchAddress(Matcher matcher) { 241 int addr = 0; 242 for (int i = 1; i <= 4; ++i) { 243 int n = (rangeCheck(Integer.parseInt(matcher.group(i)), -1, 255)); 244 addr |= ((n & 0xff) << 8*(4-i)); 245 } 246 return addr; 247 } 248 249 /* 250 * Convert a packed integer address into a 4-element array 251 */ 252 private int[] toArray(int val) { 253 int ret[] = new int[4]; 254 for (int j = 3; j >= 0; --j) { 255 ret[j] |= ((val >>> 8*(3-j)) & (0xff)); 256 } 257 return ret; 258 } 259 260 /* 261 * Convert a 4-element array into dotted decimal format 262 */ 263 private String format(int[] octets) { 264 StringBuilder str = new StringBuilder(); 265 for (int i =0; i < octets.length; ++i){ 266 str.append(octets[i]); 267 if (i != octets.length - 1) { 268 str.append("."); 269 } 270 } 271 return str.toString(); 272 } 273 274 /* 275 * Convenience function to check integer boundaries. 276 * Checks if a value x is in the range (begin,end]. 277 * Returns x if it is in range, throws an exception otherwise. 278 */ 279 private int rangeCheck(int value, int begin, int end) { 280 if (value > begin && value <= end) { // (begin,end] 281 return value; 282 } 283 284 throw new IllegalArgumentException("Value [" + value + "] not in range ("+begin+","+end+"]"); 285 } 286 287 /* 288 * Count the number of 1-bits in a 32-bit integer using a divide-and-conquer strategy 289 * see Hacker's Delight section 5.1 290 */ 291 int pop(int x) { 292 x = x - ((x >>> 1) & 0x55555555); 293 x = (x & 0x33333333) + ((x >>> 2) & 0x33333333); 294 x = (x + (x >>> 4)) & 0x0F0F0F0F; 295 x = x + (x >>> 8); 296 x = x + (x >>> 16); 297 return x & 0x0000003F; 298 } 299 300 /* Convert two dotted decimal addresses to a single xxx.xxx.xxx.xxx/yy format 301 * by counting the 1-bit population in the mask address. (It may be better to count 302 * NBITS-#trailing zeroes for this case) 303 */ 304 private String toCidrNotation(String addr, String mask) { 305 return addr + "/" + pop(toInteger(mask)); 306 } 307}