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 <linux/crc32.h> 33 #include <crypto/internal/hash.h> 34 #include <linux/init.h> 35 #include <linux/module.h> 36 #include <linux/string.h> 37 #include <linux/kernel.h> 38 39 #define CHKSUM_BLOCK_SIZE 1 40 #define CHKSUM_DIGEST_SIZE 4 41 42 static u32 __crc32_le(u32 crc, unsigned char const *p, size_t len) 43 { 44 return crc32_le(crc, p, len); 45 } 46 47 /** No default init with ~0 */ 48 static int crc32_cra_init(struct crypto_tfm *tfm) 49 { 50 u32 *key = crypto_tfm_ctx(tfm); 51 52 *key = 0; 53 54 return 0; 55 } 56 57 58 /* 59 * Setting the seed allows arbitrary accumulators and flexible XOR policy 60 * If your algorithm starts with ~0, then XOR with ~0 before you set 61 * the seed. 62 */ 63 static int crc32_setkey(struct crypto_shash *hash, const u8 *key, 64 unsigned int keylen) 65 { 66 u32 *mctx = crypto_shash_ctx(hash); 67 68 if (keylen != sizeof(u32)) { 69 crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN); 70 return -EINVAL; 71 } 72 *mctx = le32_to_cpup((__le32 *)key); 73 return 0; 74 } 75 76 static int crc32_init(struct shash_desc *desc) 77 { 78 u32 *mctx = crypto_shash_ctx(desc->tfm); 79 u32 *crcp = shash_desc_ctx(desc); 80 81 *crcp = *mctx; 82 83 return 0; 84 } 85 86 static int crc32_update(struct shash_desc *desc, const u8 *data, 87 unsigned int len) 88 { 89 u32 *crcp = shash_desc_ctx(desc); 90 91 *crcp = __crc32_le(*crcp, data, len); 92 return 0; 93 } 94 95 /* No final XOR 0xFFFFFFFF, like crc32_le */ 96 static int __crc32_finup(u32 *crcp, const u8 *data, unsigned int len, 97 u8 *out) 98 { 99 *(__le32 *)out = cpu_to_le32(__crc32_le(*crcp, data, len)); 100 return 0; 101 } 102 103 static int crc32_finup(struct shash_desc *desc, const u8 *data, 104 unsigned int len, u8 *out) 105 { 106 return __crc32_finup(shash_desc_ctx(desc), data, len, out); 107 } 108 109 static int crc32_final(struct shash_desc *desc, u8 *out) 110 { 111 u32 *crcp = shash_desc_ctx(desc); 112 113 *(__le32 *)out = cpu_to_le32p(crcp); 114 return 0; 115 } 116 117 static int crc32_digest(struct shash_desc *desc, const u8 *data, 118 unsigned int len, u8 *out) 119 { 120 return __crc32_finup(crypto_shash_ctx(desc->tfm), data, len, 121 out); 122 } 123 static struct shash_alg alg = { 124 .setkey = crc32_setkey, 125 .init = crc32_init, 126 .update = crc32_update, 127 .final = crc32_final, 128 .finup = crc32_finup, 129 .digest = crc32_digest, 130 .descsize = sizeof(u32), 131 .digestsize = CHKSUM_DIGEST_SIZE, 132 .base = { 133 .cra_name = "crc32", 134 .cra_driver_name = "crc32-generic", 135 .cra_priority = 100, 136 .cra_blocksize = CHKSUM_BLOCK_SIZE, 137 .cra_ctxsize = sizeof(u32), 138 .cra_module = THIS_MODULE, 139 .cra_init = crc32_cra_init, 140 } 141 }; 142 143 static int __init crc32_mod_init(void) 144 { 145 return crypto_register_shash(&alg); 146 } 147 148 static void __exit crc32_mod_fini(void) 149 { 150 crypto_unregister_shash(&alg); 151 } 152 153 module_init(crc32_mod_init); 154 module_exit(crc32_mod_fini); 155 156 MODULE_AUTHOR("Alexander Boyko <alexander_boyko@xyratex.com>"); 157 MODULE_DESCRIPTION("CRC32 calculations wrapper for lib/crc32"); 158 MODULE_LICENSE("GPL"); 159 MODULE_ALIAS_CRYPTO("crc32"); 160 MODULE_ALIAS_CRYPTO("crc32-generic"); 161