crypto/842.c

   1 /*
   2  * Cryptographic API for the 842 compression algorithm.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  17  *
  18  * Copyright (C) IBM Corporation, 2011
  19  *
  20  * Authors: Robert Jennings <rcj@linux.vnet.ibm.com>
  21  *          Seth Jennings <sjenning@linux.vnet.ibm.com>
  22  */
  23
  24 #include <linux/init.h>
  25 #include <linux/module.h>
  26 #include <linux/crypto.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/nx842.h>
  29 #include <linux/lzo.h>
  30 #include <linux/timer.h>
  31
  32 static int nx842_uselzo;
  33
  34 struct nx842_ctx {
  35         void *nx842_wmem; /* working memory for 842/lzo */
  36 };
  37
  38 enum nx842_crypto_type {
  39         NX842_CRYPTO_TYPE_842,
  40         NX842_CRYPTO_TYPE_LZO
  41 };
  42
  43 #define NX842_SENTINEL 0xdeadbeef
  44
  45 struct nx842_crypto_header {
  46         unsigned int sentinel; /* debug */
  47         enum nx842_crypto_type type;
  48 };
  49
  50 static int nx842_init(struct crypto_tfm *tfm)
  51 {
  52         struct nx842_ctx *ctx = crypto_tfm_ctx(tfm);
  53         int wmemsize;
  54
  55         wmemsize = max_t(int, nx842_get_workmem_size(), LZO1X_MEM_COMPRESS);
  56         ctx->nx842_wmem = kmalloc(wmemsize, GFP_NOFS);
  57         if (!ctx->nx842_wmem)
  58                 return -ENOMEM;
  59
  60         return 0;
  61 }
  62
  63 static void nx842_exit(struct crypto_tfm *tfm)
  64 {
  65         struct nx842_ctx *ctx = crypto_tfm_ctx(tfm);
  66
  67         kfree(ctx->nx842_wmem);
  68 }
  69
  70 static void nx842_reset_uselzo(unsigned long data)
  71 {
  72         nx842_uselzo = 0;
  73 }
  74
  75 static DEFINE_TIMER(failover_timer, nx842_reset_uselzo, 0, 0);
  76
  77 static int nx842_crypto_compress(struct crypto_tfm *tfm, const u8 *src,
  78                             unsigned int slen, u8 *dst, unsigned int *dlen)
  79 {
  80         struct nx842_ctx *ctx = crypto_tfm_ctx(tfm);
  81         struct nx842_crypto_header *hdr;
  82         unsigned int tmp_len = *dlen;
  83         size_t lzodlen; /* needed for lzo */
  84         int err;
  85
  86         *dlen = 0;
  87         hdr = (struct nx842_crypto_header *)dst;
  88         hdr->sentinel = NX842_SENTINEL; /* debug */
  89         dst += sizeof(struct nx842_crypto_header);
  90         tmp_len -= sizeof(struct nx842_crypto_header);
  91         lzodlen = tmp_len;
  92
  93         if (likely(!nx842_uselzo)) {
  94                 err = nx842_compress(src, slen, dst, &tmp_len, ctx->nx842_wmem);
  95
  96                 if (likely(!err)) {
  97                         hdr->type = NX842_CRYPTO_TYPE_842;
  98                         *dlen = tmp_len + sizeof(struct nx842_crypto_header);
  99                         return 0;
 100                 }
 101
 102                 /* hardware failed */
 103                 nx842_uselzo = 1;
 104
 105                 /* set timer to check for hardware again in 1 second */
 106                 mod_timer(&failover_timer, jiffies + msecs_to_jiffies(1000));
 107         }
 108
 109         /* no hardware, use lzo */
 110         err = lzo1x_1_compress(src, slen, dst, &lzodlen, ctx->nx842_wmem);
 111         if (err != LZO_E_OK)
 112                 return -EINVAL;
 113
 114         hdr->type = NX842_CRYPTO_TYPE_LZO;
 115         *dlen = lzodlen + sizeof(struct nx842_crypto_header);
 116         return 0;
 117 }
 118
 119 static int nx842_crypto_decompress(struct crypto_tfm *tfm, const u8 *src,
 120                               unsigned int slen, u8 *dst, unsigned int *dlen)
 121 {
 122         struct nx842_ctx *ctx = crypto_tfm_ctx(tfm);
 123         struct nx842_crypto_header *hdr;
 124         unsigned int tmp_len = *dlen;
 125         size_t lzodlen; /* needed for lzo */
 126         int err;
 127
 128         *dlen = 0;
 129         hdr = (struct nx842_crypto_header *)src;
 130
 131         if (unlikely(hdr->sentinel != NX842_SENTINEL))
 132                 return -EINVAL;
 133
 134         src += sizeof(struct nx842_crypto_header);
 135         slen -= sizeof(struct nx842_crypto_header);
 136
 137         if (likely(hdr->type == NX842_CRYPTO_TYPE_842)) {
 138                 err = nx842_decompress(src, slen, dst, &tmp_len,
 139                         ctx->nx842_wmem);
 140                 if (err)
 141                         return -EINVAL;
 142                 *dlen = tmp_len;
 143         } else if (hdr->type == NX842_CRYPTO_TYPE_LZO) {
 144                 lzodlen = tmp_len;
 145                 err = lzo1x_decompress_safe(src, slen, dst, &lzodlen);
 146                 if (err != LZO_E_OK)
 147                         return -EINVAL;
 148                 *dlen = lzodlen;
 149         } else
 150                 return -EINVAL;
 151
 152         return 0;
 153 }
 154
 155 static struct crypto_alg alg = {
 156         .cra_name               = "842",
 157         .cra_flags              = CRYPTO_ALG_TYPE_COMPRESS,
 158         .cra_ctxsize            = sizeof(struct nx842_ctx),
 159         .cra_module             = THIS_MODULE,
 160         .cra_init               = nx842_init,
 161         .cra_exit               = nx842_exit,
 162         .cra_u                  = { .compress = {
 163         .coa_compress           = nx842_crypto_compress,
 164         .coa_decompress         = nx842_crypto_decompress } }
 165 };
 166
 167 static int __init nx842_mod_init(void)
 168 {
 169         del_timer(&failover_timer);
 170         return crypto_register_alg(&alg);
 171 }
 172
 173 static void __exit nx842_mod_exit(void)
 174 {
 175         crypto_unregister_alg(&alg);
 176 }
 177
 178 module_init(nx842_mod_init);
 179 module_exit(nx842_mod_exit);
 180
 181 MODULE_LICENSE("GPL");
 182 MODULE_DESCRIPTION("842 Compression Algorithm");
 183 MODULE_ALIAS_CRYPTO("842");