blob: bc73342cd1ecc253909440de480909b7eab10beb [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Cryptographic API.
3 *
4 * Deflate algorithm (RFC 1951), implemented here primarily for use
5 * by IPCOMP (RFC 3173 & RFC 2394).
6 *
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.
13 *
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.
19 *
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.
22 *
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.
26 */
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>
36
37#define DEFLATE_DEF_LEVEL Z_DEFAULT_COMPRESSION
38#define DEFLATE_DEF_WINBITS 11
39#define DEFLATE_DEF_MEMLEVEL MAX_MEM_LEVEL
40
41struct deflate_ctx {
42 struct z_stream_s comp_stream;
43 struct z_stream_s decomp_stream;
44};
45
46static int deflate_comp_init(struct deflate_ctx *ctx)
47{
48 int ret = 0;
49 struct z_stream_s *stream = &ctx->comp_stream;
50
51 stream->workspace = vmalloc(zlib_deflate_workspacesize());
52 if (!stream->workspace ) {
53 ret = -ENOMEM;
54 goto out;
55 }
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;
63 }
64out:
65 return ret;
66out_free:
67 vfree(stream->workspace);
68 goto out;
69}
70
71static int deflate_decomp_init(struct deflate_ctx *ctx)
72{
73 int ret = 0;
74 struct z_stream_s *stream = &ctx->decomp_stream;
75
76 stream->workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
77 if (!stream->workspace ) {
78 ret = -ENOMEM;
79 goto out;
80 }
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;
86 }
87out:
88 return ret;
89out_free:
90 kfree(stream->workspace);
91 goto out;
92}
93
94static void deflate_comp_exit(struct deflate_ctx *ctx)
95{
Artem B. Bityuckiy9ffb7142005-04-16 15:23:58 -070096 zlib_deflateEnd(&ctx->comp_stream);
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 vfree(ctx->comp_stream.workspace);
98}
99
100static void deflate_decomp_exit(struct deflate_ctx *ctx)
101{
Artem B. Bityuckiy9ffb7142005-04-16 15:23:58 -0700102 zlib_inflateEnd(&ctx->decomp_stream);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 kfree(ctx->decomp_stream.workspace);
104}
105
106static int deflate_init(void *ctx)
107{
108 int ret;
109
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);
116out:
117 return ret;
118}
119
120static void deflate_exit(void *ctx)
121{
122 deflate_comp_exit(ctx);
123 deflate_decomp_exit(ctx);
124}
125
126static int deflate_compress(void *ctx, const u8 *src, unsigned int slen,
127 u8 *dst, unsigned int *dlen)
128{
129 int ret = 0;
130 struct deflate_ctx *dctx = ctx;
131 struct z_stream_s *stream = &dctx->comp_stream;
132
133 ret = zlib_deflateReset(stream);
134 if (ret != Z_OK) {
135 ret = -EINVAL;
136 goto out;
137 }
138
139 stream->next_in = (u8 *)src;
140 stream->avail_in = slen;
141 stream->next_out = (u8 *)dst;
142 stream->avail_out = *dlen;
143
144 ret = zlib_deflate(stream, Z_FINISH);
145 if (ret != Z_STREAM_END) {
146 ret = -EINVAL;
147 goto out;
148 }
149 ret = 0;
150 *dlen = stream->total_out;
151out:
152 return ret;
153}
154
155static int deflate_decompress(void *ctx, const u8 *src, unsigned int slen,
156 u8 *dst, unsigned int *dlen)
157{
158
159 int ret = 0;
160 struct deflate_ctx *dctx = ctx;
161 struct z_stream_s *stream = &dctx->decomp_stream;
162
163 ret = zlib_inflateReset(stream);
164 if (ret != Z_OK) {
165 ret = -EINVAL;
166 goto out;
167 }
168
169 stream->next_in = (u8 *)src;
170 stream->avail_in = slen;
171 stream->next_out = (u8 *)dst;
172 stream->avail_out = *dlen;
173
174 ret = zlib_inflate(stream, Z_SYNC_FLUSH);
175 /*
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).
179 */
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);
185 }
186 if (ret != Z_STREAM_END) {
187 ret = -EINVAL;
188 goto out;
189 }
190 ret = 0;
191 *dlen = stream->total_out;
192out:
193 return ret;
194}
195
196static 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 } }
207};
208
209static int __init init(void)
210{
211 return crypto_register_alg(&alg);
212}
213
214static void __exit fini(void)
215{
216 crypto_unregister_alg(&alg);
217}
218
219module_init(init);
220module_exit(fini);
221
222MODULE_LICENSE("GPL");
223MODULE_DESCRIPTION("Deflate Compression Algorithm for IPCOMP");
224MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
225