1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 *
19 */
20
21 package org.apache.mina.filter.firewall;
22
23 import java.net.Inet4Address;
24 import java.net.InetAddress;
25
26 /**
27 * A IP subnet using the CIDR notation. Currently, only IP version 4
28 * address are supported.
29 *
30 * @author The Apache MINA Project (dev@mina.apache.org)
31 * @version $Rev: 636538 $, $Date: 2008-03-12 22:19:27 +0000 (Wed, 12 Mar 2008) $
32 */
33 public class Subnet {
34
35 private static final int IP_MASK = 0x80000000;
36 private static final int BYTE_MASK = 0xFF;
37
38 private InetAddress subnet;
39 private int subnetInt;
40 private int subnetMask;
41 private int suffix;
42
43 /**
44 * Creates a subnet from CIDR notation. For example, the subnet
45 * 192.168.0.0/24 would be created using the {@link InetAddress}
46 * 192.168.0.0 and the mask 24.
47 * @param subnet The {@link InetAddress} of the subnet
48 * @param mask The mask
49 */
50 public Subnet(InetAddress subnet, int mask) {
51 if(subnet == null) {
52 throw new NullPointerException("Subnet address can not be null");
53 }
54 if(!(subnet instanceof Inet4Address)) {
55 throw new IllegalArgumentException("Only IPv4 supported");
56 }
57
58 if(mask < 0 || mask > 32) {
59 throw new IllegalArgumentException("Mask has to be an integer between 0 and 32");
60 }
61
62 this.subnet = subnet;
63 this.subnetInt = toInt(subnet);
64 this.suffix = mask;
65
66 // binary mask for this subnet
67 this.subnetMask = IP_MASK >> (mask - 1);
68 }
69
70 /**
71 * Converts an IP address into an integer
72 */
73 private int toInt(InetAddress inetAddress) {
74 byte[] address = inetAddress.getAddress();
75 int result = 0;
76 for (int i = 0; i < address.length; i++) {
77 result <<= 8;
78 result |= address[i] & BYTE_MASK;
79 }
80 return result;
81 }
82
83 /**
84 * Converts an IP address to a subnet using the provided
85 * mask
86 * @param address The address to convert into a subnet
87 * @return The subnet as an integer
88 */
89 private int toSubnet(InetAddress address) {
90 return toInt(address) & subnetMask;
91 }
92
93 /**
94 * Checks if the {@link InetAddress} is within this subnet
95 * @param address The {@link InetAddress} to check
96 * @return True if the address is within this subnet, false otherwise
97 */
98 public boolean inSubnet(InetAddress address) {
99 return toSubnet(address) == subnetInt;
100 }
101
102 /**
103 * @see Object#toString()
104 */
105 @Override
106 public String toString() {
107 return subnet.getHostAddress() + "/" + suffix;
108 }
109
110 @Override
111 public boolean equals(Object obj) {
112 if(!(obj instanceof Subnet)) {
113 return false;
114 }
115
116 Subnet other = (Subnet) obj;
117
118 return other.subnetInt == subnetInt && other.suffix == suffix;
119 }
120
121
122 }