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