The Android Open Source Project | 0eec464 | 2012-04-01 00:00:00 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Licensed to the Apache Software Foundation (ASF) under one or more |
| 3 | * contributor license agreements. See the NOTICE file distributed with |
| 4 | * this work for additional information regarding copyright ownership. |
| 5 | * The ASF licenses this file to You under the Apache License, Version 2.0 |
| 6 | * (the "License"); you may not use this file except in compliance with |
| 7 | * the License. You may obtain a copy of the License at |
| 8 | * |
| 9 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 10 | * |
| 11 | * Unless required by applicable law or agreed to in writing, software |
| 12 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 14 | * See the License for the specific language governing permissions and |
| 15 | * limitations under the License. |
| 16 | */ |
| 17 | |
| 18 | package org.apache.harmony.xnet.provider.jsse; |
| 19 | |
| 20 | import javax.crypto.Cipher; |
| 21 | |
| 22 | /** |
| 23 | * This abstract class is a base for Record Protocol operating environmet |
| 24 | * of different SSL protocol versions. |
| 25 | */ |
| 26 | public abstract class ConnectionState { |
| 27 | |
| 28 | /** |
| 29 | * The cipher used for encode operations |
| 30 | */ |
| 31 | protected Cipher encCipher; |
| 32 | |
| 33 | /** |
| 34 | * The cipher used for decode operations |
| 35 | */ |
| 36 | protected Cipher decCipher; |
| 37 | |
| 38 | /** |
| 39 | * The block size, or zero if not a block cipher |
| 40 | */ |
| 41 | protected int block_size; |
| 42 | |
| 43 | /** |
| 44 | * The size of MAC used under this connection state |
| 45 | */ |
| 46 | protected int hash_size; |
| 47 | |
| 48 | /** |
| 49 | * Write sequence number which is incremented after each |
| 50 | * encrypt call |
| 51 | */ |
| 52 | protected final byte[] write_seq_num = {0, 0, 0, 0, 0, 0, 0, 0}; |
| 53 | |
| 54 | /** |
| 55 | * Read sequence number which is incremented after each |
| 56 | * decrypt call |
| 57 | */ |
| 58 | protected final byte[] read_seq_num = {0, 0, 0, 0, 0, 0, 0, 0}; |
| 59 | |
| 60 | protected Logger.Stream logger = Logger.getStream("conn_state"); |
| 61 | |
| 62 | /** |
| 63 | * Returns the minimal possible size of the |
| 64 | * Generic[Stream|Generic]Cipher structure under this |
| 65 | * connection state. |
| 66 | */ |
| 67 | protected int getMinFragmentSize() { |
| 68 | // block ciphers return value with padding included |
| 69 | return encCipher.getOutputSize(1+hash_size); // 1 byte for data |
| 70 | } |
| 71 | |
| 72 | /** |
| 73 | * Returns the size of the Generic[Stream|Generic]Cipher structure |
| 74 | * corresponding to the content data of specified size. |
| 75 | */ |
| 76 | protected int getFragmentSize(int content_size) { |
| 77 | return encCipher.getOutputSize(content_size+hash_size); |
| 78 | } |
| 79 | |
| 80 | /** |
| 81 | * Returns the minimal upper bound of the content size enclosed |
| 82 | * into the Generic[Stream|Generic]Cipher structure of specified size. |
| 83 | * For stream ciphers the returned value will be exact value. |
| 84 | */ |
| 85 | protected int getContentSize(int generic_cipher_size) { |
| 86 | //it does not take the padding of block ciphered structures |
| 87 | //into account (so returned value can be greater than actual) |
| 88 | return decCipher.getOutputSize(generic_cipher_size)-hash_size; |
| 89 | } |
| 90 | |
| 91 | /** |
| 92 | * Returns the number of bytes of padding required to round the |
| 93 | * content up to the required block size. Assumes power of two |
| 94 | * block size. |
| 95 | */ |
| 96 | protected int getPaddingSize(int content_size) { |
| 97 | int mask = block_size - 1; |
| 98 | return (block_size - (content_size & mask)); |
| 99 | } |
| 100 | |
| 101 | /** |
| 102 | * Creates the GenericStreamCipher or GenericBlockCipher |
| 103 | * data structure for specified data of specified type. |
| 104 | * @param type - the ContentType of the provided data |
| 105 | * @param fragment - the byte array containing the |
| 106 | * data to be encrypted under the current connection state. |
| 107 | */ |
| 108 | protected byte[] encrypt(byte type, byte[] fragment) { |
| 109 | return encrypt(type, fragment, 0, fragment.length); |
| 110 | } |
| 111 | |
| 112 | /** |
| 113 | * Creates the GenericStreamCipher or GenericBlockCipher |
| 114 | * data structure for specified data of specified type. |
| 115 | * @param type - the ContentType of the provided data |
| 116 | * @param fragment - the byte array containing the |
| 117 | * data to be encrypted under the current connection state. |
| 118 | * @param offset - the offset from which the data begins with. |
| 119 | * @param len - the length of the data. |
| 120 | */ |
| 121 | protected abstract byte[] encrypt |
| 122 | (byte type, byte[] fragment, int offset, int len); |
| 123 | |
| 124 | /** |
| 125 | * Retrieves the fragment of the Plaintext structure of |
| 126 | * the specified type from the provided data. |
| 127 | * @param type - the ContentType of the data to be decrypted. |
| 128 | * @param fragment - the byte array containing the |
| 129 | * data to be encrypted under the current connection state. |
| 130 | */ |
| 131 | protected byte[] decrypt(byte type, byte[] fragment) { |
| 132 | return decrypt(type, fragment, 0, fragment.length); |
| 133 | } |
| 134 | |
| 135 | /** |
| 136 | * Retrieves the fragment of the Plaintext structure of |
| 137 | * the specified type from the provided data. |
| 138 | * @param type - the ContentType of the data to be decrypted. |
| 139 | * @param fragment - the byte array containing the |
| 140 | * data to be encrypted under the current connection state. |
| 141 | * @param offset - the offset from which the data begins with. |
| 142 | * @param len - the length of the data. |
| 143 | */ |
| 144 | protected abstract byte[] decrypt |
| 145 | (byte type, byte[] fragment, int offset, int len); |
| 146 | |
| 147 | /** |
| 148 | * Increments the sequence number. |
| 149 | */ |
| 150 | protected static void incSequenceNumber(byte[] seq_num) { |
| 151 | int octet = 7; |
| 152 | while (octet >= 0) { |
| 153 | seq_num[octet] ++; |
| 154 | if (seq_num[octet] == 0) { |
| 155 | // characteristic overflow, so |
| 156 | // carrying a number in adding |
| 157 | octet --; |
| 158 | } else { |
| 159 | return; |
| 160 | } |
| 161 | } |
| 162 | } |
| 163 | |
| 164 | /** |
| 165 | * Shutdownes the protocol. It will be impossiblke to use the instance |
| 166 | * after the calling of this method. |
| 167 | */ |
| 168 | protected void shutdown() { |
| 169 | encCipher = null; |
| 170 | decCipher = null; |
| 171 | for (int i=0; i<write_seq_num.length; i++) { |
| 172 | write_seq_num[i] = 0; |
| 173 | read_seq_num[i] = 0; |
| 174 | } |
| 175 | } |
| 176 | } |
| 177 | |