[PATCH] I2C: Kill i2c_algorithm.id (6/7)
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / crypto / deflate.c
blobbc73342cd1ecc253909440de480909b7eab10beb
1 /*
2 * Cryptographic API.
4 * Deflate algorithm (RFC 1951), implemented here primarily for use
5 * by IPCOMP (RFC 3173 & RFC 2394).
7 * Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
8 *
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License as published by the Free
11 * Software Foundation; either version 2 of the License, or (at your option)
12 * any later version.
14 * FIXME: deflate transforms will require up to a total of about 436k of kernel
15 * memory on i386 (390k for compression, the rest for decompression), as the
16 * current zlib kernel code uses a worst case pre-allocation system by default.
17 * This needs to be fixed so that the amount of memory required is properly
18 * related to the winbits and memlevel parameters.
20 * The default winbits of 11 should suit most packets, and it may be something
21 * to configure on a per-tfm basis in the future.
23 * Currently, compression history is not maintained between tfm calls, as
24 * it is not needed for IPCOMP and keeps the code simpler. It can be
25 * implemented if someone wants it.
27 #include <linux/init.h>
28 #include <linux/module.h>
29 #include <linux/crypto.h>
30 #include <linux/zlib.h>
31 #include <linux/vmalloc.h>
32 #include <linux/interrupt.h>
33 #include <linux/mm.h>
34 #include <linux/net.h>
35 #include <linux/slab.h>
37 #define DEFLATE_DEF_LEVEL Z_DEFAULT_COMPRESSION
38 #define DEFLATE_DEF_WINBITS 11
39 #define DEFLATE_DEF_MEMLEVEL MAX_MEM_LEVEL
41 struct deflate_ctx {
42 struct z_stream_s comp_stream;
43 struct z_stream_s decomp_stream;
46 static int deflate_comp_init(struct deflate_ctx *ctx)
48 int ret = 0;
49 struct z_stream_s *stream = &ctx->comp_stream;
51 stream->workspace = vmalloc(zlib_deflate_workspacesize());
52 if (!stream->workspace ) {
53 ret = -ENOMEM;
54 goto out;
56 memset(stream->workspace, 0, zlib_deflate_workspacesize());
57 ret = zlib_deflateInit2(stream, DEFLATE_DEF_LEVEL, Z_DEFLATED,
58 -DEFLATE_DEF_WINBITS, DEFLATE_DEF_MEMLEVEL,
59 Z_DEFAULT_STRATEGY);
60 if (ret != Z_OK) {
61 ret = -EINVAL;
62 goto out_free;
64 out:
65 return ret;
66 out_free:
67 vfree(stream->workspace);
68 goto out;
71 static int deflate_decomp_init(struct deflate_ctx *ctx)
73 int ret = 0;
74 struct z_stream_s *stream = &ctx->decomp_stream;
76 stream->workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
77 if (!stream->workspace ) {
78 ret = -ENOMEM;
79 goto out;
81 memset(stream->workspace, 0, zlib_inflate_workspacesize());
82 ret = zlib_inflateInit2(stream, -DEFLATE_DEF_WINBITS);
83 if (ret != Z_OK) {
84 ret = -EINVAL;
85 goto out_free;
87 out:
88 return ret;
89 out_free:
90 kfree(stream->workspace);
91 goto out;
94 static void deflate_comp_exit(struct deflate_ctx *ctx)
96 zlib_deflateEnd(&ctx->comp_stream);
97 vfree(ctx->comp_stream.workspace);
100 static void deflate_decomp_exit(struct deflate_ctx *ctx)
102 zlib_inflateEnd(&ctx->decomp_stream);
103 kfree(ctx->decomp_stream.workspace);
106 static int deflate_init(void *ctx)
108 int ret;
110 ret = deflate_comp_init(ctx);
111 if (ret)
112 goto out;
113 ret = deflate_decomp_init(ctx);
114 if (ret)
115 deflate_comp_exit(ctx);
116 out:
117 return ret;
120 static void deflate_exit(void *ctx)
122 deflate_comp_exit(ctx);
123 deflate_decomp_exit(ctx);
126 static int deflate_compress(void *ctx, const u8 *src, unsigned int slen,
127 u8 *dst, unsigned int *dlen)
129 int ret = 0;
130 struct deflate_ctx *dctx = ctx;
131 struct z_stream_s *stream = &dctx->comp_stream;
133 ret = zlib_deflateReset(stream);
134 if (ret != Z_OK) {
135 ret = -EINVAL;
136 goto out;
139 stream->next_in = (u8 *)src;
140 stream->avail_in = slen;
141 stream->next_out = (u8 *)dst;
142 stream->avail_out = *dlen;
144 ret = zlib_deflate(stream, Z_FINISH);
145 if (ret != Z_STREAM_END) {
146 ret = -EINVAL;
147 goto out;
149 ret = 0;
150 *dlen = stream->total_out;
151 out:
152 return ret;
155 static int deflate_decompress(void *ctx, const u8 *src, unsigned int slen,
156 u8 *dst, unsigned int *dlen)
159 int ret = 0;
160 struct deflate_ctx *dctx = ctx;
161 struct z_stream_s *stream = &dctx->decomp_stream;
163 ret = zlib_inflateReset(stream);
164 if (ret != Z_OK) {
165 ret = -EINVAL;
166 goto out;
169 stream->next_in = (u8 *)src;
170 stream->avail_in = slen;
171 stream->next_out = (u8 *)dst;
172 stream->avail_out = *dlen;
174 ret = zlib_inflate(stream, Z_SYNC_FLUSH);
176 * Work around a bug in zlib, which sometimes wants to taste an extra
177 * byte when being used in the (undocumented) raw deflate mode.
178 * (From USAGI).
180 if (ret == Z_OK && !stream->avail_in && stream->avail_out) {
181 u8 zerostuff = 0;
182 stream->next_in = &zerostuff;
183 stream->avail_in = 1;
184 ret = zlib_inflate(stream, Z_FINISH);
186 if (ret != Z_STREAM_END) {
187 ret = -EINVAL;
188 goto out;
190 ret = 0;
191 *dlen = stream->total_out;
192 out:
193 return ret;
196 static struct crypto_alg alg = {
197 .cra_name = "deflate",
198 .cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
199 .cra_ctxsize = sizeof(struct deflate_ctx),
200 .cra_module = THIS_MODULE,
201 .cra_list = LIST_HEAD_INIT(alg.cra_list),
202 .cra_u = { .compress = {
203 .coa_init = deflate_init,
204 .coa_exit = deflate_exit,
205 .coa_compress = deflate_compress,
206 .coa_decompress = deflate_decompress } }
209 static int __init init(void)
211 return crypto_register_alg(&alg);
214 static void __exit fini(void)
216 crypto_unregister_alg(&alg);
219 module_init(init);
220 module_exit(fini);
222 MODULE_LICENSE("GPL");
223 MODULE_DESCRIPTION("Deflate Compression Algorithm for IPCOMP");
224 MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");