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 <a href="http://mina.apache.org">Apache MINA Project</a>
31 */
32 public class Subnet {
33
34 private static final int IP_MASK_V4 = 0x80000000;
35
36 private static final long IP_MASK_V6 = 0x8000000000000000L;
37
38 private static final int BYTE_MASK = 0xFF;
39
40 private InetAddress subnet;
41
42 /** An int representation of a subnet for IPV4 addresses */
43 private int subnetInt;
44
45 /** An long representation of a subnet for IPV6 addresses */
46 private long subnetLong;
47
48 private long subnetMask;
49
50 private int suffix;
51
52 /**
53 * Creates a subnet from CIDR notation. For example, the subnet
54 * 192.168.0.0/24 would be created using the {@link InetAddress}
55 * 192.168.0.0 and the mask 24.
56 * @param subnet The {@link InetAddress} of the subnet
57 * @param mask The mask
58 */
59 public Subnet(InetAddress subnet, int mask) {
60 if (subnet == null) {
61 throw new IllegalArgumentException("Subnet address can not be null");
62 }
63
64 if (!(subnet instanceof Inet4Address)) {
65 throw new IllegalArgumentException("Only IPv4 supported");
66 }
67
68 if (subnet instanceof Inet4Address) {
69 // IPV4 address
70 if ((mask < 0) || (mask > 32)) {
71 throw new IllegalArgumentException("Mask has to be an integer between 0 and 32 for an IPV4 address");
72 } else {
73 this.subnet = subnet;
74 subnetInt = toInt(subnet);
75 this.suffix = mask;
76
77 // binary mask for this subnet
78 this.subnetMask = IP_MASK_V4 >> (mask - 1);
79 }
80 } else {
81 // IPV6 address
82 if ((mask < 0) || (mask > 128)) {
83 throw new IllegalArgumentException("Mask has to be an integer between 0 and 128 for an IPV6 address");
84 } else {
85 this.subnet = subnet;
86 subnetLong = toLong(subnet);
87 this.suffix = mask;
88
89 // binary mask for this subnet
90 this.subnetMask = IP_MASK_V6 >> (mask - 1);
91 }
92 }
93 }
94
95 /**
96 * Converts an IP address into an integer
97 */
98 private int toInt(InetAddress inetAddress) {
99 byte[] address = inetAddress.getAddress();
100 int result = 0;
101
102 for (int i = 0; i < address.length; i++) {
103 result <<= 8;
104 result |= address[i] & BYTE_MASK;
105 }
106
107 return result;
108 }
109
110 /**
111 * Converts an IP address into a long
112 */
113 private long toLong(InetAddress inetAddress) {
114 byte[] address = inetAddress.getAddress();
115 long result = 0;
116
117 for (int i = 0; i < address.length; i++) {
118 result <<= 8;
119 result |= address[i] & BYTE_MASK;
120 }
121
122 return result;
123 }
124
125 /**
126 * Converts an IP address to a subnet using the provided mask
127 *
128 * @param address
129 * The address to convert into a subnet
130 * @return The subnet as an integer
131 */
132 private long toSubnet(InetAddress address) {
133 if (address instanceof Inet4Address) {
134 return toInt(address) & (int) subnetMask;
135 } else {
136 return toLong(address) & subnetMask;
137 }
138 }
139
140 /**
141 * Checks if the {@link InetAddress} is within this subnet
142 * @param address The {@link InetAddress} to check
143 * @return True if the address is within this subnet, false otherwise
144 */
145 public boolean inSubnet(InetAddress address) {
146 if (address.isAnyLocalAddress()) {
147 return true;
148 }
149
150 if (address instanceof Inet4Address) {
151 return (int) toSubnet(address) == subnetInt;
152 } else {
153 return toSubnet(address) == subnetLong;
154 }
155 }
156
157 /**
158 * @see Object#toString()
159 */
160 @Override
161 public String toString() {
162 return subnet.getHostAddress() + "/" + suffix;
163 }
164
165 @Override
166 public boolean equals(Object obj) {
167 if (!(obj instanceof Subnet)) {
168 return false;
169 }
170
171 Subnet other = (Subnet) obj;
172
173 return other.subnetInt == subnetInt && other.suffix == suffix;
174 }
175
176 }