PortCommandHandler.java revision 4ca3386623ce60063f27955ad1b2b1b6cbba8b09 
1/*
2 * Copyright 2007 the original author or authors.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://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,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16package org.mockftpserver.stub.command;
17
18import java.net.InetAddress;
19import java.net.UnknownHostException;
20import java.util.Arrays;
21
22import org.apache.log4j.Logger;
23import org.mockftpserver.core.command.Command;
24import org.mockftpserver.core.command.CommandHandler;
25import org.mockftpserver.core.command.InvocationRecord;
26import org.mockftpserver.core.command.ReplyCodes;
27import org.mockftpserver.core.session.Session;
28import org.mockftpserver.core.util.Assert;
29import org.mockftpserver.core.util.AssertFailedException;
30
31/**
32 * CommandHandler for the PORT command. Send back a reply code of 200.
33 * <p>
34 * Each invocation record stored by this CommandHandler includes the following data element key/values:
35 * <ul>
36 *    <li>{@link #HOST_KEY} ("host") - the client data host (InetAddress) submitted on the invocation (from parameters 1-4)
37 *    <li>{@link #PORT_KEY} ("port") - the port number (Integer) submitted on the invocation (from parameter 5-6)
38 * </ul>
39 *
40 * @version $Revision$ - $Date$
41 *
42 * @author Chris Mair
43 */
44public final class PortCommandHandler extends AbstractStubCommandHandler implements CommandHandler {
45
46    public static final String HOST_KEY = "host";
47    public static final String PORT_KEY = "port";
48    private static final Logger LOG = Logger.getLogger(PortCommandHandler.class);
49
50    /**
51     * Constructor. Initialize the replyCode.
52     */
53    public PortCommandHandler() {
54        setReplyCode(ReplyCodes.PORT_OK);
55    }
56
57    /**
58     * @throws UnknownHostException
59     * @throws UnknownHostException
60     * @see org.mockftpserver.core.command.CommandHandler#handleCommand(Command, Session, InvocationRecord)
61     */
62    public void handleCommand(Command command, Session session, InvocationRecord invocationRecord) throws UnknownHostException {
63        InetAddress host = parseHost(command.getParameters());
64        int port = parsePortNumber(command.getParameters());
65        LOG.debug("host=" + host + " port=" + port);
66        session.setClientDataHost(host);
67        session.setClientDataPort(port);
68        invocationRecord.set(HOST_KEY, host);
69        invocationRecord.set(PORT_KEY, new Integer(port));
70        sendReply(session);
71    }
72
73    /**
74     * Parse a 32-bit IP address from the String[] of FTP command parameters.
75     *
76     * @param parameters - the String[] of command parameters. It is the concatenation
77     *      of a 32-bit internet host address and a 16-bit TCP port address. This address
78     *      information is broken into 8-bit fields and the value of each field is encoded
79     *      as a separate parameter whose value is a decimal number (in character string
80     *      representation).  Thus, the six parameters for the port command would be:
81     *              h1,h2,h3,h4,p1,p2
82     *      where h1 is the high order 8 bits of the internet host address, and p1 is the
83     *      high order 8 bits of the port number.
84     *
85     * @return the InetAddres representing the host parsed from the parameters
86     *
87     * @throws AssertFailedException - if parameters is null or contains an insufficient number of elements
88     * @throws NumberFormatException - if one of the parameters does not contain a parsable integer
89     * @throws UnknownHostException
90     */
91    static InetAddress parseHost(String[] parameters) throws UnknownHostException {
92        verifySufficientParameters(parameters);
93
94        byte host1 = Byte.parseByte(parameters[0]);
95        byte host2 = Byte.parseByte(parameters[1]);
96        byte host3 = Byte.parseByte(parameters[2]);
97        byte host4 = Byte.parseByte(parameters[3]);
98
99        byte[] address = { host1, host2, host3, host4 };
100        InetAddress inetAddress = InetAddress.getByAddress(address);
101
102        return inetAddress;
103    }
104
105    /**
106     * Parse a 16-bit port number from the String[] of FTP command parameters.
107     *
108     * @param parameters - the String[] of command parameters. It is the concatenation
109     *      of a 32-bit internet host address and a 16-bit TCP port address. This address
110     *      information is broken into 8-bit fields and the value of each field is encoded
111     *      as a separate parameter whose value is a decimal number (in character string
112     *      representation).  Thus, the six parameters for the port command would be:
113     *              h1,h2,h3,h4,p1,p2
114     *      where h1 is the high order 8 bits of the internet host address, and p1 is the
115     *      high order 8 bits of the port number.
116     *
117     * @return the port number parsed from the parameters
118     *
119     * @throws AssertFailedException - if parameters is null or contains an insufficient number of elements
120     * @throws NumberFormatException - if one of the parameters does not contain a parsable integer
121     */
122    static int parsePortNumber(String[] parameters) {
123        verifySufficientParameters(parameters);
124
125        int port1 = Integer.parseInt(parameters[4]);
126        int port2 = Integer.parseInt(parameters[5]);
127        int port = (port1 << 8) + port2;
128
129        return port;
130    }
131
132    /**
133     * Verify that the parameters is not null and contains the required number of elements
134     * @param parameters - the String[] of command parameters
135     * @throws AssertFailedException - if parameters is null or contains an insufficient number of elements
136     */
137    private static void verifySufficientParameters(String[] parameters) {
138        Assert.notNull(parameters, "parameters");
139        Assert.isTrue(parameters.length >= 6, "The PORT command must contain least be 6 parameters: " + Arrays.asList(parameters));
140    }
141
142}
143