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Diffstat (limited to 'org/apache/commons/net/util/SubnetUtils.java')
| -rw-r--r-- | org/apache/commons/net/util/SubnetUtils.java | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/org/apache/commons/net/util/SubnetUtils.java b/org/apache/commons/net/util/SubnetUtils.java new file mode 100644 index 0000000..90cc6e8 --- /dev/null +++ b/org/apache/commons/net/util/SubnetUtils.java @@ -0,0 +1,211 @@ +/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.net.util;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * A class that performs some subnet calculations given a network address and a subnet mask.
+ * @see http://www.faqs.org/rfcs/rfc1519.html
+ * @author <rwinston@apache.org>
+ * @since 2.0
+ */
+public class SubnetUtils {
+
+ private static final String IP_ADDRESS = "(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})";
+ private static final String SLASH_FORMAT = IP_ADDRESS + "/(\\d{1,3})";
+ private static final Pattern addressPattern = Pattern.compile(IP_ADDRESS);
+ private static final Pattern cidrPattern = Pattern.compile(SLASH_FORMAT);
+ private static final int NBITS = 32;
+
+ private int netmask = 0;
+ private int address = 0;
+ private int network = 0;
+ private int broadcast = 0;
+
+ /**
+ * Constructor that takes a CIDR-notation string, e.g. "192.168.0.1/16"
+ * @param cidrNotation A CIDR-notation string, e.g. "192.168.0.1/16"
+ */
+ public SubnetUtils(String cidrNotation) {
+ calculate(cidrNotation);
+ }
+
+ /**
+ * Constructor that takes two dotted decimal addresses.
+ * @param address An IP address, e.g. "192.168.0.1"
+ * @param mask A dotted decimal netmask e.g. "255.255.0.0"
+ */
+ public SubnetUtils(String address, String mask) {
+ calculate(toCidrNotation(address, mask));
+ }
+
+ /**
+ * Convenience container for subnet summary information.
+ *
+ */
+ public final class SubnetInfo {
+ private SubnetInfo() {}
+
+ private int netmask() { return netmask; }
+ private int network() { return network; }
+ private int address() { return address; }
+ private int broadcast() { return broadcast; }
+ private int low() { return network() + 1; }
+ private int high() { return broadcast() - 1; }
+
+ public boolean isInRange(String address) { return isInRange(toInteger(address)); }
+ private boolean isInRange(int address) { return ((address-low()) <= (high()-low())); }
+
+ public String getBroadcastAddress() { return format(toArray(broadcast())); }
+ public String getNetworkAddress() { return format(toArray(network())); }
+ public String getNetmask() { return format(toArray(netmask())); }
+ public String getAddress() { return format(toArray(address())); }
+ public String getLowAddress() { return format(toArray(low())); }
+ public String getHighAddress() { return format(toArray(high())); }
+ public int getAddressCount() { return (broadcast() - low()); }
+
+ public int asInteger(String address) { return toInteger(address); }
+
+ public String getCidrSignature() {
+ return toCidrNotation(
+ format(toArray(address())),
+ format(toArray(netmask()))
+ );
+ }
+
+ public String[] getAllAddresses() {
+ String[] addresses = new String[getAddressCount()];
+ for (int add = low(), j=0; add <= high(); ++add, ++j) {
+ addresses[j] = format(toArray(add));
+ }
+ return addresses;
+ }
+ }
+
+ /**
+ * Return a {@link SubnetInfo} instance that contains subnet-specific statistics
+ * @return
+ */
+ public final SubnetInfo getInfo() { return new SubnetInfo(); }
+
+ /*
+ * Initialize the internal fields from the supplied CIDR mask
+ */
+ private void calculate(String mask) {
+ Matcher matcher = cidrPattern.matcher(mask);
+
+ if (matcher.matches()) {
+ address = matchAddress(matcher);
+
+ /* Create a binary netmask from the number of bits specification /x */
+ int cidrPart = rangeCheck(Integer.parseInt(matcher.group(5)), 0, NBITS-1);
+ for (int j = 0; j < cidrPart; ++j) {
+ netmask |= (1 << 31-j);
+ }
+
+ /* Calculate base network address */
+ network = (address & netmask);
+
+ /* Calculate broadcast address */
+ broadcast = network | ~(netmask);
+ }
+ else
+ throw new IllegalArgumentException("Could not parse [" + mask + "]");
+ }
+
+ /*
+ * Convert a dotted decimal format address to a packed integer format
+ */
+ private int toInteger(String address) {
+ Matcher matcher = addressPattern.matcher(address);
+ if (matcher.matches()) {
+ return matchAddress(matcher);
+ }
+ else
+ throw new IllegalArgumentException("Could not parse [" + address + "]");
+ }
+
+ /*
+ * Convenience method to extract the components of a dotted decimal address and
+ * pack into an integer using a regex match
+ */
+ private int matchAddress(Matcher matcher) {
+ int addr = 0;
+ for (int i = 1; i <= 4; ++i) {
+ int n = (rangeCheck(Integer.parseInt(matcher.group(i)), 0, 255));
+ addr |= ((n & 0xff) << 8*(4-i));
+ }
+ return addr;
+ }
+
+ /*
+ * Convert a packed integer address into a 4-element array
+ */
+ private int[] toArray(int val) {
+ int ret[] = new int[4];
+ for (int j = 3; j >= 0; --j)
+ ret[j] |= ((val >>> 8*(3-j)) & (0xff));
+ return ret;
+ }
+
+ /*
+ * Convert a 4-element array into dotted decimal format
+ */
+ private String format(int[] octets) {
+ StringBuilder str = new StringBuilder();
+ for (int i =0; i < octets.length; ++i){
+ str.append(octets[i]);
+ if (i != octets.length - 1) {
+ str.append(".");
+ }
+ }
+ return str.toString();
+ }
+
+ /*
+ * Convenience function to check integer boundaries
+ */
+ private int rangeCheck(int value, int begin, int end) {
+ if (value >= begin && value <= end)
+ return value;
+
+ throw new IllegalArgumentException("Value out of range: [" + value + "]");
+ }
+
+ /*
+ * Count the number of 1-bits in a 32-bit integer using a divide-and-conquer strategy
+ * see Hacker's Delight section 5.1
+ */
+ int pop(int x) {
+ x = x - ((x >>> 1) & 0x55555555);
+ x = (x & 0x33333333) + ((x >>> 2) & 0x33333333);
+ x = (x + (x >>> 4)) & 0x0F0F0F0F;
+ x = x + (x >>> 8);
+ x = x + (x >>> 16);
+ return x & 0x0000003F;
+ }
+
+ /* Convert two dotted decimal addresses to a single xxx.xxx.xxx.xxx/yy format
+ * by counting the 1-bit population in the mask address. (It may be better to count
+ * NBITS-#trailing zeroes for this case)
+ */
+ private String toCidrNotation(String addr, String mask) {
+ return addr + "/" + pop(toInteger(mask));
+ }
+}
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