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 */
32 public class Subnet {
33
34 private static final int IP_MASK = 0x80000000;
35 private static final int BYTE_MASK = 0xFF;
36
37 private InetAddress subnet;
38 private int subnetInt;
39 private int subnetMask;
40 private int suffix;
41
42 /**
43 * Creates a subnet from CIDR notation. For example, the subnet
44 * 192.168.0.0/24 would be created using the {@link InetAddress}
45 * 192.168.0.0 and the mask 24.
46 * @param subnet The {@link InetAddress} of the subnet
47 * @param mask The mask
48 */
49 public Subnet(InetAddress subnet, int mask) {
50 if(subnet == null) {
51 throw new NullPointerException("Subnet address can not be null");
52 }
53 if(!(subnet instanceof Inet4Address)) {
54 throw new IllegalArgumentException("Only IPv4 supported");
55 }
56
57 if(mask < 0 || mask > 32) {
58 throw new IllegalArgumentException("Mask has to be an integer between 0 and 32");
59 }
60
61 this.subnet = subnet;
62 this.subnetInt = toInt(subnet);
63 this.suffix = mask;
64
65 // binary mask for this subnet
66 this.subnetMask = IP_MASK >> (mask - 1);
67 }
68
69 /**
70 * Converts an IP address into an integer
71 */
72 private int toInt(InetAddress inetAddress) {
73 byte[] address = inetAddress.getAddress();
74 int result = 0;
75 for (int i = 0; i < address.length; i++) {
76 result <<= 8;
77 result |= address[i] & BYTE_MASK;
78 }
79 return result;
80 }
81
82 /**
83 * Converts an IP address to a subnet using the provided
84 * mask
85 * @param address The address to convert into a subnet
86 * @return The subnet as an integer
87 */
88 private int toSubnet(InetAddress address) {
89 return toInt(address) & subnetMask;
90 }
91
92 /**
93 * Checks if the {@link InetAddress} is within this subnet
94 * @param address The {@link InetAddress} to check
95 * @return True if the address is within this subnet, false otherwise
96 */
97 public boolean inSubnet(InetAddress address) {
98 return toSubnet(address) == subnetInt;
99 }
100
101 /**
102 * @see Object#toString()
103 */
104 @Override
105 public String toString() {
106 return subnet.getHostAddress() + "/" + suffix;
107 }
108
109 @Override
110 public boolean equals(Object obj) {
111 if(!(obj instanceof Subnet)) {
112 return false;
113 }
114
115 Subnet other = (Subnet) obj;
116
117 return other.subnetInt == subnetInt && other.suffix == suffix;
118 }
119
120
121 }