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 package org.apache.mina.proxy.handlers.socks;
21
22 import java.util.Arrays;
23
24 import org.apache.mina.core.buffer.IoBuffer;
25 import org.apache.mina.core.filterchain.IoFilter.NextFilter;
26 import org.apache.mina.proxy.session.ProxyIoSession;
27 import org.apache.mina.proxy.utils.ByteUtilities;
28 import org.slf4j.Logger;
29 import org.slf4j.LoggerFactory;
30
31 /**
32 * Socks4LogicHandler.java - SOCKS4/SOCKS4a authentication mechanisms logic handler.
33 *
34 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
35 * @since MINA 2.0.0-M3
36 */
37 public class Socks4LogicHandler extends AbstractSocksLogicHandler {
38
39 private final static Logger logger = LoggerFactory.getLogger(Socks4LogicHandler.class);
40
41 /**
42 * @see AbstractSocksLogicHandler#AbstractSocksLogicHandler(ProxyIoSession)
43 *
44 * @param proxyIoSession The original session
45 */
46 public Socks4LogicHandler(final ProxyIoSession proxyIoSession) {
47 super(proxyIoSession);
48 }
49
50 /**
51 * Perform the handshake.
52 *
53 * @param nextFilter the next filter
54 */
55 public void doHandshake(final NextFilter nextFilter) {
56 logger.debug(" doHandshake()");
57
58 // Send request
59 writeRequest(nextFilter, request);
60 }
61
62 /**
63 * Encode a SOCKS4/SOCKS4a request and writes it to the next filter
64 * so it can be sent to the proxy server.
65 *
66 * @param nextFilter the next filter
67 * @param request the request to send.
68 */
69 protected void writeRequest(final NextFilter nextFilter, final SocksProxyRequest request) {
70 try {
71 boolean isV4ARequest = Arrays.equals(request.getIpAddress(), SocksProxyConstants.FAKE_IP);
72 byte[] userID = request.getUserName().getBytes("ASCII");
73 byte[] host = isV4ARequest ? request.getHost().getBytes("ASCII") : null;
74
75 int len = 9 + userID.length;
76
77 if (isV4ARequest) {
78 len += host.length + 1;
79 }
80
81 IoBuffer buf = IoBuffer.allocate(len);
82
83 buf.put(request.getProtocolVersion());
84 buf.put(request.getCommandCode());
85 buf.put(request.getPort());
86 buf.put(request.getIpAddress());
87 buf.put(userID);
88 buf.put(SocksProxyConstants.TERMINATOR);
89
90 if (isV4ARequest) {
91 buf.put(host);
92 buf.put(SocksProxyConstants.TERMINATOR);
93 }
94
95 if (isV4ARequest) {
96 logger.debug(" sending SOCKS4a request");
97 } else {
98 logger.debug(" sending SOCKS4 request");
99 }
100
101 buf.flip();
102 writeData(nextFilter, buf);
103 } catch (Exception ex) {
104 closeSession("Unable to send Socks request: ", ex);
105 }
106 }
107
108 /**
109 * Handle incoming data during the handshake process. Should consume only the
110 * handshake data from the buffer, leaving any extra data in place.
111 *
112 * @param nextFilter the next filter
113 * @param buf the server response data buffer
114 */
115 public void messageReceived(final NextFilter nextFilter, final IoBuffer buf) {
116 try {
117 if (buf.remaining() >= SocksProxyConstants.SOCKS_4_RESPONSE_SIZE) {
118 handleResponse(buf);
119 }
120 } catch (Exception ex) {
121 closeSession("Proxy handshake failed: ", ex);
122 }
123 }
124
125 /**
126 * Handle a SOCKS4/SOCKS4a response from the proxy server. Test
127 * the response buffer reply code and call {@link #setHandshakeComplete()}
128 * if access is granted.
129 *
130 * @param buf the buffer holding the server response data.
131 * @throws Exception if server response is malformed or if request is rejected
132 * by the proxy server.
133 */
134 protected void handleResponse(final IoBuffer buf) throws Exception {
135 byte first = buf.get(0);
136
137 if (first != 0) {
138 throw new Exception("Socks response seems to be malformed");
139 }
140
141 byte status = buf.get(1);
142
143 // Consumes all the response data from the buffer
144 buf.position(buf.position() + SocksProxyConstants.SOCKS_4_RESPONSE_SIZE);
145
146 if (status == SocksProxyConstants.V4_REPLY_REQUEST_GRANTED) {
147 setHandshakeComplete();
148 } else {
149 throw new Exception("Proxy handshake failed - Code: 0x" + ByteUtilities.asHex(new byte[] { status }) + " ("
150 + SocksProxyConstants.getReplyCodeAsString(status) + ")");
151 }
152 }
153 }