1/*
2 * Copyright 2008 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.core.util;
17
18import org.mockftpserver.core.CommandSyntaxException;
19import org.mockftpserver.core.MockFtpServerException;
20
21import java.net.InetAddress;
22import java.net.UnknownHostException;
23import java.util.Arrays;
24import java.util.List;
25
26/**
27 * Utility class for parsing host and port values from command arguments.
28 *
29 * @author Chris Mair
30 * @version $Revision$ - $Date$
31 */
32public final class PortParser {
33
34    /**
35     * Parse the host address and port number of an extended address. This encoded format is used by
36     * the EPRT FTP command, and supports IPv6.
37     * <p/>
38     * The client network address can be in IPv4 format (e.g., "132.235.1.2") or
39     * IPv6 format (e.g., "1080::8:800:200C:417A"). See RFC2428 for more information.
40     *
41     * @param parameter - the single parameter String containing the encoded host and port number
42     * @return the populated HostAndPort object
43     */
44    public static HostAndPort parseExtendedAddressHostAndPort(String parameter) {
45        if (parameter == null || parameter.length() == 0) {
46            throw new CommandSyntaxException("The parameter string must not be empty or null");
47        }
48
49        String delimiter = parameter.substring(0,1);
50        String[] tokens = parameter.split("\\" + delimiter);
51
52        if (tokens.length < 4) {
53            throw new CommandSyntaxException("Error parsing host and port number [" + parameter + "]");
54        }
55
56        int port = Integer.parseInt(tokens[3]);
57
58        InetAddress host;
59        try {
60            host = InetAddress.getByName(tokens[2]);
61        }
62        catch (UnknownHostException e) {
63            throw new CommandSyntaxException("Error parsing host [" + tokens[2] + "]", e);
64        }
65
66        return new HostAndPort(host, port);
67    }
68
69    /**
70     * Parse a 32-bit IP address and 16-bit port number from the String[] of FTP command parameters.
71     * This is used by the FTP "PORT" command.
72     *
73     * @param parameters - the String[] of command parameters. It is the concatenation
74     *                   of a 32-bit internet host address and a 16-bit TCP port address. This address
75     *                   information is broken into 8-bit fields and the value of each field is encoded
76     *                   as a separate parameter whose value is a decimal number (in character string
77     *                   representation).  Thus, the six parameters for the port command would be:
78     *                   h1,h2,h3,h4,p1,p2
79     *                   where h1 is the high order 8 bits of the internet host address, and p1 is the
80     *                   high order 8 bits of the port number.
81     * @return the HostAndPort object with the host InetAddres and int port parsed from the parameters
82     * @throws org.mockftpserver.core.util.AssertFailedException
83     *                               - if parameters is null or contains an insufficient number of elements
84     * @throws NumberFormatException - if one of the parameters does not contain a parsable integer
85     */
86    public static HostAndPort parseHostAndPort(String[] parameters) {
87        verifySufficientParameters(parameters);
88
89        byte host1 = parseByte(parameters[0]);
90        byte host2 = parseByte(parameters[1]);
91        byte host3 = parseByte(parameters[2]);
92        byte host4 = parseByte(parameters[3]);
93
94        byte[] address = {host1, host2, host3, host4};
95        InetAddress inetAddress = null;
96        try {
97            inetAddress = InetAddress.getByAddress(address);
98        }
99        catch (UnknownHostException e) {
100            throw new MockFtpServerException("Error parsing host", e);
101        }
102
103        int port1 = Integer.parseInt(parameters[4]);
104        int port2 = Integer.parseInt(parameters[5]);
105        int port = (port1 << 8) + port2;
106
107        return new HostAndPort(inetAddress, port);
108    }
109
110    /**
111     * Convert the InetAddess and port number to a comma-delimited list of byte values,
112     * suitable for the response String from the PASV command.
113     *
114     * @param host - the InetAddress
115     * @param port - the port number
116     * @return the comma-delimited list of byte values, e.g., "196,168,44,55,23,77"
117     */
118    public static String convertHostAndPortToCommaDelimitedBytes(InetAddress host, int port) {
119        StringBuffer buffer = new StringBuffer();
120        byte[] address = host.getAddress();
121        for (int i = 0; i < address.length; i++) {
122            int positiveValue = (address[i] >= 0) ? address[i] : 256 + address[i];
123            buffer.append(positiveValue);
124            buffer.append(",");
125        }
126        int p1 = port >> 8;
127        int p2 = port % 256;
128        buffer.append(String.valueOf(p1));
129        buffer.append(",");
130        buffer.append(String.valueOf(p2));
131        return buffer.toString();
132    }
133
134    /**
135     * Verify that the parameters is not null and contains the required number of elements
136     *
137     * @param parameters - the String[] of command parameters
138     * @throws CommandSyntaxException - if parameters is null or contains an insufficient number of elements
139     */
140    private static void verifySufficientParameters(String[] parameters) {
141        if (parameters == null || parameters.length < 6) {
142            List parms = parameters == null ? null : Arrays.asList(parameters);
143            throw new CommandSyntaxException("The PORT command must contain least be 6 parameters: " + parms);
144        }
145    }
146
147    /**
148     * Parse the specified String as an unsigned decimal byte value (i.e., 0..255). We can't just use
149     * Byte.parseByte(string) because that parses the string as a signed byte.
150     *
151     * @param string - the String containing the decimal byte representation to be parsed
152     * @return the byte value
153     */
154    private static byte parseByte(String string) {
155        return (byte) (0xFF & Short.parseShort(string));
156    }
157
158    /**
159     * Private constructor. All methods are static.
160     */
161    private PortParser() {
162    }
163
164}