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      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  */
     16 package org.mockftpserver.core.util;
     17 
     18 import org.mockftpserver.core.CommandSyntaxException;
     19 import org.mockftpserver.core.MockFtpServerException;
     20 
     21 import java.net.InetAddress;
     22 import java.net.UnknownHostException;
     23 import java.util.Arrays;
     24 import 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  */
     32 public 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 }