1 /* GPL HEADER START 2 * 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 only, 7 * as published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it will be useful, but 10 * WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 * General Public License version 2 for more details (a copy is included 13 * in the LICENSE file that accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License 16 * version 2 along with this program; If not, see http://www.gnu.org/licenses 17 * 18 * Please visit http://www.xyratex.com/contact if you need additional 19 * information or have any questions. 20 * 21 * GPL HEADER END 22 */ 23 24 /* 25 * Copyright 2012 Xyratex Technology Limited 26 */ 27 28 /* 29 * This is crypto api shash wrappers to crc32_le. 30 */ 31 32 #include <asm/unaligned.h> 33 #include <linux/crc32.h> 34 #include <crypto/internal/hash.h> 35 #include <linux/init.h> 36 #include <linux/module.h> 37 #include <linux/string.h> 38 #include <linux/kernel.h> 39 40 #define CHKSUM_BLOCK_SIZE 1 41 #define CHKSUM_DIGEST_SIZE 4 42 43 /** No default init with ~0 */ 44 static int crc32_cra_init(struct crypto_tfm *tfm) 45 { 46 u32 *key = crypto_tfm_ctx(tfm); 47 48 *key = 0; 49 50 return 0; 51 } 52 53 /* 54 * Setting the seed allows arbitrary accumulators and flexible XOR policy 55 * If your algorithm starts with ~0, then XOR with ~0 before you set 56 * the seed. 57 */ 58 static int crc32_setkey(struct crypto_shash *hash, const u8 *key, 59 unsigned int keylen) 60 { 61 u32 *mctx = crypto_shash_ctx(hash); 62 63 if (keylen != sizeof(u32)) { 64 crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN); 65 return -EINVAL; 66 } 67 *mctx = get_unaligned_le32(key); 68 return 0; 69 } 70 71 static int crc32_init(struct shash_desc *desc) 72 { 73 u32 *mctx = crypto_shash_ctx(desc->tfm); 74 u32 *crcp = shash_desc_ctx(desc); 75 76 *crcp = *mctx; 77 78 return 0; 79 } 80 81 static int crc32_update(struct shash_desc *desc, const u8 *data, 82 unsigned int len) 83 { 84 u32 *crcp = shash_desc_ctx(desc); 85 86 *crcp = crc32_le(*crcp, data, len); 87 return 0; 88 } 89 90 /* No final XOR 0xFFFFFFFF, like crc32_le */ 91 static int __crc32_finup(u32 *crcp, const u8 *data, unsigned int len, 92 u8 *out) 93 { 94 put_unaligned_le32(crc32_le(*crcp, data, len), out); 95 return 0; 96 } 97 98 static int crc32_finup(struct shash_desc *desc, const u8 *data, 99 unsigned int len, u8 *out) 100 { 101 return __crc32_finup(shash_desc_ctx(desc), data, len, out); 102 } 103 104 static int crc32_final(struct shash_desc *desc, u8 *out) 105 { 106 u32 *crcp = shash_desc_ctx(desc); 107 108 put_unaligned_le32(*crcp, out); 109 return 0; 110 } 111 112 static int crc32_digest(struct shash_desc *desc, const u8 *data, 113 unsigned int len, u8 *out) 114 { 115 return __crc32_finup(crypto_shash_ctx(desc->tfm), data, len, 116 out); 117 } 118 static struct shash_alg alg = { 119 .setkey = crc32_setkey, 120 .init = crc32_init, 121 .update = crc32_update, 122 .final = crc32_final, 123 .finup = crc32_finup, 124 .digest = crc32_digest, 125 .descsize = sizeof(u32), 126 .digestsize = CHKSUM_DIGEST_SIZE, 127 .base = { 128 .cra_name = "crc32", 129 .cra_driver_name = "crc32-generic", 130 .cra_priority = 100, 131 .cra_flags = CRYPTO_ALG_OPTIONAL_KEY, 132 .cra_blocksize = CHKSUM_BLOCK_SIZE, 133 .cra_ctxsize = sizeof(u32), 134 .cra_module = THIS_MODULE, 135 .cra_init = crc32_cra_init, 136 } 137 }; 138 139 static int __init crc32_mod_init(void) 140 { 141 return crypto_register_shash(&alg); 142 } 143 144 static void __exit crc32_mod_fini(void) 145 { 146 crypto_unregister_shash(&alg); 147 } 148 149 subsys_initcall(crc32_mod_init); 150 module_exit(crc32_mod_fini); 151 152 MODULE_AUTHOR("Alexander Boyko <alexander_boyko@xyratex.com>"); 153 MODULE_DESCRIPTION("CRC32 calculations wrapper for lib/crc32"); 154 MODULE_LICENSE("GPL"); 155 MODULE_ALIAS_CRYPTO("crc32"); 156 MODULE_ALIAS_CRYPTO("crc32-generic"); 157