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Linux/crypto/842.c

  1 /*
  2  * Cryptographic API for the 842 software 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  * Copyright (C) IBM Corporation, 2011-2015
 15  *
 16  * Original Authors: Robert Jennings <rcj@linux.vnet.ibm.com>
 17  *                   Seth Jennings <sjenning@linux.vnet.ibm.com>
 18  *
 19  * Rewrite: Dan Streetman <ddstreet@ieee.org>
 20  *
 21  * This is the software implementation of compression and decompression using
 22  * the 842 format.  This uses the software 842 library at lib/842/ which is
 23  * only a reference implementation, and is very, very slow as compared to other
 24  * software compressors.  You probably do not want to use this software
 25  * compression.  If you have access to the PowerPC 842 compression hardware, you
 26  * want to use the 842 hardware compression interface, which is at:
 27  * drivers/crypto/nx/nx-842-crypto.c
 28  */
 29 
 30 #include <linux/init.h>
 31 #include <linux/module.h>
 32 #include <linux/crypto.h>
 33 #include <linux/sw842.h>
 34 #include <crypto/internal/scompress.h>
 35 
 36 struct crypto842_ctx {
 37         void *wmem;     /* working memory for compress */
 38 };
 39 
 40 static void *crypto842_alloc_ctx(struct crypto_scomp *tfm)
 41 {
 42         void *ctx;
 43 
 44         ctx = kmalloc(SW842_MEM_COMPRESS, GFP_KERNEL);
 45         if (!ctx)
 46                 return ERR_PTR(-ENOMEM);
 47 
 48         return ctx;
 49 }
 50 
 51 static int crypto842_init(struct crypto_tfm *tfm)
 52 {
 53         struct crypto842_ctx *ctx = crypto_tfm_ctx(tfm);
 54 
 55         ctx->wmem = crypto842_alloc_ctx(NULL);
 56         if (IS_ERR(ctx->wmem))
 57                 return -ENOMEM;
 58 
 59         return 0;
 60 }
 61 
 62 static void crypto842_free_ctx(struct crypto_scomp *tfm, void *ctx)
 63 {
 64         kfree(ctx);
 65 }
 66 
 67 static void crypto842_exit(struct crypto_tfm *tfm)
 68 {
 69         struct crypto842_ctx *ctx = crypto_tfm_ctx(tfm);
 70 
 71         crypto842_free_ctx(NULL, ctx->wmem);
 72 }
 73 
 74 static int crypto842_compress(struct crypto_tfm *tfm,
 75                               const u8 *src, unsigned int slen,
 76                               u8 *dst, unsigned int *dlen)
 77 {
 78         struct crypto842_ctx *ctx = crypto_tfm_ctx(tfm);
 79 
 80         return sw842_compress(src, slen, dst, dlen, ctx->wmem);
 81 }
 82 
 83 static int crypto842_scompress(struct crypto_scomp *tfm,
 84                                const u8 *src, unsigned int slen,
 85                                u8 *dst, unsigned int *dlen, void *ctx)
 86 {
 87         return sw842_compress(src, slen, dst, dlen, ctx);
 88 }
 89 
 90 static int crypto842_decompress(struct crypto_tfm *tfm,
 91                                 const u8 *src, unsigned int slen,
 92                                 u8 *dst, unsigned int *dlen)
 93 {
 94         return sw842_decompress(src, slen, dst, dlen);
 95 }
 96 
 97 static int crypto842_sdecompress(struct crypto_scomp *tfm,
 98                                  const u8 *src, unsigned int slen,
 99                                  u8 *dst, unsigned int *dlen, void *ctx)
100 {
101         return sw842_decompress(src, slen, dst, dlen);
102 }
103 
104 static struct crypto_alg alg = {
105         .cra_name               = "842",
106         .cra_driver_name        = "842-generic",
107         .cra_priority           = 100,
108         .cra_flags              = CRYPTO_ALG_TYPE_COMPRESS,
109         .cra_ctxsize            = sizeof(struct crypto842_ctx),
110         .cra_module             = THIS_MODULE,
111         .cra_init               = crypto842_init,
112         .cra_exit               = crypto842_exit,
113         .cra_u                  = { .compress = {
114         .coa_compress           = crypto842_compress,
115         .coa_decompress         = crypto842_decompress } }
116 };
117 
118 static struct scomp_alg scomp = {
119         .alloc_ctx              = crypto842_alloc_ctx,
120         .free_ctx               = crypto842_free_ctx,
121         .compress               = crypto842_scompress,
122         .decompress             = crypto842_sdecompress,
123         .base                   = {
124                 .cra_name       = "842",
125                 .cra_driver_name = "842-scomp",
126                 .cra_priority    = 100,
127                 .cra_module      = THIS_MODULE,
128         }
129 };
130 
131 static int __init crypto842_mod_init(void)
132 {
133         int ret;
134 
135         ret = crypto_register_alg(&alg);
136         if (ret)
137                 return ret;
138 
139         ret = crypto_register_scomp(&scomp);
140         if (ret) {
141                 crypto_unregister_alg(&alg);
142                 return ret;
143         }
144 
145         return ret;
146 }
147 module_init(crypto842_mod_init);
148 
149 static void __exit crypto842_mod_exit(void)
150 {
151         crypto_unregister_alg(&alg);
152         crypto_unregister_scomp(&scomp);
153 }
154 module_exit(crypto842_mod_exit);
155 
156 MODULE_LICENSE("GPL");
157 MODULE_DESCRIPTION("842 Software Compression Algorithm");
158 MODULE_ALIAS_CRYPTO("842");
159 MODULE_ALIAS_CRYPTO("842-generic");
160 MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>");
161 

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