Root/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
32static int nx842_uselzo;
33
34struct nx842_ctx {
35    void *nx842_wmem; /* working memory for 842/lzo */
36};
37
38enum nx842_crypto_type {
39    NX842_CRYPTO_TYPE_842,
40    NX842_CRYPTO_TYPE_LZO
41};
42
43#define NX842_SENTINEL 0xdeadbeef
44
45struct nx842_crypto_header {
46    unsigned int sentinel; /* debug */
47    enum nx842_crypto_type type;
48};
49
50static 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
63static 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
70static void nx842_reset_uselzo(unsigned long data)
71{
72    nx842_uselzo = 0;
73}
74
75static DEFINE_TIMER(failover_timer, nx842_reset_uselzo, 0, 0);
76
77static 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
119static 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
155static 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
167static int __init nx842_mod_init(void)
168{
169    del_timer(&failover_timer);
170    return crypto_register_alg(&alg);
171}
172
173static void __exit nx842_mod_exit(void)
174{
175    crypto_unregister_alg(&alg);
176}
177
178module_init(nx842_mod_init);
179module_exit(nx842_mod_exit);
180
181MODULE_LICENSE("GPL");
182MODULE_DESCRIPTION("842 Compression Algorithm");
183

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