PortParser.java revision 899f9bd64499ce2a3f8492399e4910f27a8e1e4a
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}