1 /*
2 * Copyright 2012 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License,
5 * version 2.0 (the "License"); you may not use this file except in compliance
6 * with the License. You may obtain a copy of the License at:
7 *
8 * https://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 package io.netty.handler.codec.socks;
17
18 import io.netty.buffer.ByteBuf;
19 import io.netty.util.CharsetUtil;
20 import io.netty.util.NetUtil;
21 import io.netty.util.internal.ObjectUtil;
22
23 import java.net.IDN;
24
25 /**
26 * A socks cmd response.
27 *
28 * @see SocksCmdRequest
29 * @see SocksCmdResponseDecoder
30 */
31 public final class SocksCmdResponse extends SocksResponse {
32 private final SocksCmdStatus cmdStatus;
33
34 private final SocksAddressType addressType;
35 private final String host;
36 private final int port;
37
38 // All arrays are initialized on construction time to 0/false/null remove array Initialization
39 private static final byte[] DOMAIN_ZEROED = {0x00};
40 private static final byte[] IPv4_HOSTNAME_ZEROED = {0x00, 0x00, 0x00, 0x00};
41 private static final byte[] IPv6_HOSTNAME_ZEROED = {0x00, 0x00, 0x00, 0x00,
42 0x00, 0x00, 0x00, 0x00,
43 0x00, 0x00, 0x00, 0x00,
44 0x00, 0x00, 0x00, 0x00};
45
46 public SocksCmdResponse(SocksCmdStatus cmdStatus, SocksAddressType addressType) {
47 this(cmdStatus, addressType, null, 0);
48 }
49
50 /**
51 * Constructs new response and includes provided host and port as part of it.
52 *
53 * @param cmdStatus status of the response
54 * @param addressType type of host parameter
55 * @param host host (BND.ADDR field) is address that server used when connecting to the target host.
56 * When null a value of 4/8 0x00 octets will be used for IPv4/IPv6 and a single 0x00 byte will be
57 * used for domain addressType. Value is converted to ASCII using {@link IDN#toASCII(String)}.
58 * @param port port (BND.PORT field) that the server assigned to connect to the target host
59 * @throws NullPointerException in case cmdStatus or addressType are missing
60 * @throws IllegalArgumentException in case host or port cannot be validated
61 * @see IDN#toASCII(String)
62 */
63 public SocksCmdResponse(SocksCmdStatus cmdStatus, SocksAddressType addressType, String host, int port) {
64 super(SocksResponseType.CMD);
65 ObjectUtil.checkNotNull(cmdStatus, "cmdStatus");
66 ObjectUtil.checkNotNull(addressType, "addressType");
67 if (host != null) {
68 switch (addressType) {
69 case IPv4:
70 if (!NetUtil.isValidIpV4Address(host)) {
71 throw new IllegalArgumentException(host + " is not a valid IPv4 address");
72 }
73 break;
74 case DOMAIN:
75 String asciiHost = IDN.toASCII(host);
76 if (asciiHost.length() > 255) {
77 throw new IllegalArgumentException(host + " IDN: " + asciiHost + " exceeds 255 char limit");
78 }
79 host = asciiHost;
80 break;
81 case IPv6:
82 if (!NetUtil.isValidIpV6Address(host)) {
83 throw new IllegalArgumentException(host + " is not a valid IPv6 address");
84 }
85 break;
86 case UNKNOWN:
87 break;
88 }
89 }
90 if (port < 0 || port > 65535) {
91 throw new IllegalArgumentException(port + " is not in bounds 0 <= x <= 65535");
92 }
93 this.cmdStatus = cmdStatus;
94 this.addressType = addressType;
95 this.host = host;
96 this.port = port;
97 }
98
99 /**
100 * Returns the {@link SocksCmdStatus} of this {@link SocksCmdResponse}
101 *
102 * @return The {@link SocksCmdStatus} of this {@link SocksCmdResponse}
103 */
104 public SocksCmdStatus cmdStatus() {
105 return cmdStatus;
106 }
107
108 /**
109 * Returns the {@link SocksAddressType} of this {@link SocksCmdResponse}
110 *
111 * @return The {@link SocksAddressType} of this {@link SocksCmdResponse}
112 */
113 public SocksAddressType addressType() {
114 return addressType;
115 }
116
117 /**
118 * Returns host that is used as a parameter in {@link SocksCmdType}.
119 * Host (BND.ADDR field in response) is address that server used when connecting to the target host.
120 * This is typically different from address which client uses to connect to the SOCKS server.
121 *
122 * @return host that is used as a parameter in {@link SocksCmdType}
123 * or null when there was no host specified during response construction
124 */
125 public String host() {
126 return host != null && addressType == SocksAddressType.DOMAIN ? IDN.toUnicode(host) : host;
127 }
128
129 /**
130 * Returns port that is used as a parameter in {@link SocksCmdType}.
131 * Port (BND.PORT field in response) is port that the server assigned to connect to the target host.
132 *
133 * @return port that is used as a parameter in {@link SocksCmdType}
134 */
135 public int port() {
136 return port;
137 }
138
139 @Override
140 public void encodeAsByteBuf(ByteBuf byteBuf) {
141 byteBuf.writeByte(protocolVersion().byteValue());
142 byteBuf.writeByte(cmdStatus.byteValue());
143 byteBuf.writeByte(0x00);
144 byteBuf.writeByte(addressType.byteValue());
145 switch (addressType) {
146 case IPv4: {
147 byte[] hostContent = host == null ?
148 IPv4_HOSTNAME_ZEROED : NetUtil.createByteArrayFromIpAddressString(host);
149 byteBuf.writeBytes(hostContent);
150 byteBuf.writeShort(port);
151 break;
152 }
153 case DOMAIN: {
154 if (host != null) {
155 byteBuf.writeByte(host.length());
156 byteBuf.writeCharSequence(host, CharsetUtil.US_ASCII);
157 } else {
158 byteBuf.writeByte(DOMAIN_ZEROED.length);
159 byteBuf.writeBytes(DOMAIN_ZEROED);
160 }
161 byteBuf.writeShort(port);
162 break;
163 }
164 case IPv6: {
165 byte[] hostContent = host == null
166 ? IPv6_HOSTNAME_ZEROED : NetUtil.createByteArrayFromIpAddressString(host);
167 byteBuf.writeBytes(hostContent);
168 byteBuf.writeShort(port);
169 break;
170 }
171 }
172 }
173 }