libcfs/libcfs/linux/linux-crypto-crc32.c

   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/module.h>
  33 #include <linux/crc32.h>
  34 #ifdef HAVE_STRUCT_SHASH_ALG
  35 #include <crypto/internal/hash.h>
  36 #else
  37 #include <linux/crypto.h>
  38 #endif
  39
  40 #define CHKSUM_BLOCK_SIZE       1
  41 #define CHKSUM_DIGEST_SIZE      4
  42
  43 static u32 __crc32_le(u32 crc, unsigned char const *p, size_t len)
  44 {
  45         return crc32_le(crc, p, len);
  46 }
  47
  48 /** No default init with ~0 */
  49 static int crc32_cra_init(struct crypto_tfm *tfm)
  50 {
  51         u32 *key = crypto_tfm_ctx(tfm);
  52
  53         *key = 0;
  54
  55         return 0;
  56 }
  57
  58
  59 #ifdef HAVE_STRUCT_SHASH_ALG
  60 /*
  61  * Setting the seed allows arbitrary accumulators and flexible XOR policy
  62  * If your algorithm starts with ~0, then XOR with ~0 before you set
  63  * the seed.
  64  */
  65 static int crc32_setkey(struct crypto_shash *hash, const u8 *key,
  66                         unsigned int keylen)
  67 {
  68         u32 *mctx = crypto_shash_ctx(hash);
  69
  70         if (keylen != sizeof(u32)) {
  71                 crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
  72                 return -EINVAL;
  73         }
  74         *mctx = le32_to_cpup((__le32 *)key);
  75         return 0;
  76 }
  77
  78 static int crc32_init(struct shash_desc *desc)
  79 {
  80         u32 *mctx = crypto_shash_ctx(desc->tfm);
  81         u32 *crcp = shash_desc_ctx(desc);
  82
  83         *crcp = *mctx;
  84
  85         return 0;
  86 }
  87
  88 static int crc32_update(struct shash_desc *desc, const u8 *data,
  89                         unsigned int len)
  90 {
  91         u32 *crcp = shash_desc_ctx(desc);
  92
  93         *crcp = __crc32_le(*crcp, data, len);
  94         return 0;
  95 }
  96 /* No final XOR 0xFFFFFFFF, like crc32_le */
  97 static int __crc32_finup(u32 *crcp, const u8 *data, unsigned int len,
  98                          u8 *out)
  99 {
 100         *(__le32 *)out = cpu_to_le32(__crc32_le(*crcp, data, len));
 101         return 0;
 102 }
 103
 104 static int crc32_finup(struct shash_desc *desc, const u8 *data,
 105                        unsigned int len, u8 *out)
 106 {
 107         return __crc32_finup(shash_desc_ctx(desc), data, len, out);
 108 }
 109
 110 static int crc32_final(struct shash_desc *desc, u8 *out)
 111 {
 112         u32 *crcp = shash_desc_ctx(desc);
 113
 114         *(__le32 *)out = cpu_to_le32p(crcp);
 115         return 0;
 116 }
 117
 118 static int crc32_digest(struct shash_desc *desc, const u8 *data,
 119                         unsigned int len, u8 *out)
 120 {
 121         return __crc32_finup(crypto_shash_ctx(desc->tfm), data, len,
 122                              out);
 123 }
 124 static struct shash_alg alg = {
 125         .setkey         = crc32_setkey,
 126         .init           = crc32_init,
 127         .update         = crc32_update,
 128         .final          = crc32_final,
 129         .finup          = crc32_finup,
 130         .digest         = crc32_digest,
 131         .descsize       = sizeof(u32),
 132         .digestsize     = CHKSUM_DIGEST_SIZE,
 133         .base           = {
 134                 .cra_name               = "crc32",
 135                 .cra_driver_name        = "crc32-table",
 136                 .cra_priority           = 100,
 137                 .cra_blocksize          = CHKSUM_BLOCK_SIZE,
 138                 .cra_ctxsize            = sizeof(u32),
 139                 .cra_module             = THIS_MODULE,
 140                 .cra_init               = crc32_cra_init,
 141         }
 142 };
 143 #else   /* HAVE_STRUCT_SHASH_ALG */
 144 #ifdef HAVE_DIGEST_SETKEY_FLAGS
 145 static int crc32_digest_setkey(struct crypto_tfm *tfm, const u8 *key,
 146                                unsigned int keylen, unsigned int *flags)
 147 #else
 148 static int crc32_digest_setkey(struct crypto_tfm *tfm, const u8 *key,
 149                                unsigned int keylen)
 150 #endif
 151 {
 152         u32 *mctx = crypto_tfm_ctx(tfm);
 153
 154         if (keylen != sizeof(u32)) {
 155                 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
 156                 return -EINVAL;
 157         }
 158         *mctx = le32_to_cpup((__le32 *)key);
 159         return 0;
 160 }
 161
 162 static void crc32_digest_init(struct crypto_tfm *tfm)
 163 {
 164         u32 *mctx = crypto_tfm_ctx(tfm);
 165
 166         *mctx = 0;
 167
 168 }
 169 static void crc32_digest_update(struct crypto_tfm *tfm, const u8 *data,
 170                                 unsigned int len)
 171 {
 172         u32 *crcp = crypto_tfm_ctx(tfm);
 173
 174         *crcp = __crc32_le(*crcp, data, len);
 175 }
 176
 177 static void crc32_digest_final(struct crypto_tfm *tfm, u8 *out)
 178 {
 179         u32 *crcp = crypto_tfm_ctx(tfm);
 180
 181         *(__le32 *)out = cpu_to_le32p(crcp);
 182 }
 183
 184 static struct crypto_alg alg = {
 185         .cra_name               = "crc32",
 186         .cra_flags              = CRYPTO_ALG_TYPE_DIGEST,
 187         .cra_driver_name        = "crc32-table",
 188         .cra_priority           = 100,
 189         .cra_blocksize          = CHKSUM_BLOCK_SIZE,
 190         .cra_ctxsize            = sizeof(u32),
 191         .cra_module             = THIS_MODULE,
 192         .cra_init               = crc32_cra_init,
 193         .cra_list               = LIST_HEAD_INIT(alg.cra_list),
 194         .cra_u                  = {
 195                 .digest         = {
 196                         .dia_digestsize = CHKSUM_DIGEST_SIZE,
 197                         .dia_setkey     = crc32_digest_setkey,
 198                         .dia_init       = crc32_digest_init,
 199                         .dia_update     = crc32_digest_update,
 200                         .dia_final      = crc32_digest_final
 201                 }
 202         }
 203 };
 204 #endif  /* HAVE_STRUCT_SHASH_ALG */
 205
 206 int cfs_crypto_crc32_register(void)
 207 {
 208 #ifdef HAVE_STRUCT_SHASH_ALG
 209         return crypto_register_shash(&alg);
 210 #else
 211         return crypto_register_alg(&alg);
 212 #endif
 213 }
 214 EXPORT_SYMBOL(cfs_crypto_crc32_register);
 215
 216 void cfs_crypto_crc32_unregister(void)
 217 {
 218 #ifdef HAVE_STRUCT_SHASH_ALG
 219         crypto_unregister_shash(&alg);
 220 #else
 221         crypto_unregister_alg(&alg);
 222 #endif
 223 }
 224 EXPORT_SYMBOL(cfs_crypto_crc32_unregister);