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1 | /* | |
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 | ||
36 | #define DEFLATE_DEF_LEVEL Z_DEFAULT_COMPRESSION | |
37 | #define DEFLATE_DEF_WINBITS 11 | |
38 | #define DEFLATE_DEF_MEMLEVEL MAX_MEM_LEVEL | |
39 | ||
40 | struct deflate_ctx { | |
41 | struct z_stream_s comp_stream; | |
42 | struct z_stream_s decomp_stream; | |
43 | }; | |
44 | ||
45 | static int deflate_comp_init(struct deflate_ctx *ctx) | |
46 | { | |
47 | int ret = 0; | |
48 | struct z_stream_s *stream = &ctx->comp_stream; | |
49 | ||
50 | stream->workspace = vzalloc(zlib_deflate_workspacesize( | |
51 | -DEFLATE_DEF_WINBITS, DEFLATE_DEF_MEMLEVEL)); | |
52 | if (!stream->workspace) { | |
53 | ret = -ENOMEM; | |
54 | goto out; | |
55 | } | |
56 | ret = zlib_deflateInit2(stream, DEFLATE_DEF_LEVEL, Z_DEFLATED, | |
57 | -DEFLATE_DEF_WINBITS, DEFLATE_DEF_MEMLEVEL, | |
58 | Z_DEFAULT_STRATEGY); | |
59 | if (ret != Z_OK) { | |
60 | ret = -EINVAL; | |
61 | goto out_free; | |
62 | } | |
63 | out: | |
64 | return ret; | |
65 | out_free: | |
66 | vfree(stream->workspace); | |
67 | goto out; | |
68 | } | |
69 | ||
70 | static int deflate_decomp_init(struct deflate_ctx *ctx) | |
71 | { | |
72 | int ret = 0; | |
73 | struct z_stream_s *stream = &ctx->decomp_stream; | |
74 | ||
75 | stream->workspace = vzalloc(zlib_inflate_workspacesize()); | |
76 | if (!stream->workspace) { | |
77 | ret = -ENOMEM; | |
78 | goto out; | |
79 | } | |
80 | ret = zlib_inflateInit2(stream, -DEFLATE_DEF_WINBITS); | |
81 | if (ret != Z_OK) { | |
82 | ret = -EINVAL; | |
83 | goto out_free; | |
84 | } | |
85 | out: | |
86 | return ret; | |
87 | out_free: | |
88 | vfree(stream->workspace); | |
89 | goto out; | |
90 | } | |
91 | ||
92 | static void deflate_comp_exit(struct deflate_ctx *ctx) | |
93 | { | |
94 | zlib_deflateEnd(&ctx->comp_stream); | |
95 | vfree(ctx->comp_stream.workspace); | |
96 | } | |
97 | ||
98 | static void deflate_decomp_exit(struct deflate_ctx *ctx) | |
99 | { | |
100 | zlib_inflateEnd(&ctx->decomp_stream); | |
101 | vfree(ctx->decomp_stream.workspace); | |
102 | } | |
103 | ||
104 | static int deflate_init(struct crypto_tfm *tfm) | |
105 | { | |
106 | struct deflate_ctx *ctx = crypto_tfm_ctx(tfm); | |
107 | int ret; | |
108 | ||
109 | ret = deflate_comp_init(ctx); | |
110 | if (ret) | |
111 | goto out; | |
112 | ret = deflate_decomp_init(ctx); | |
113 | if (ret) | |
114 | deflate_comp_exit(ctx); | |
115 | out: | |
116 | return ret; | |
117 | } | |
118 | ||
119 | static void deflate_exit(struct crypto_tfm *tfm) | |
120 | { | |
121 | struct deflate_ctx *ctx = crypto_tfm_ctx(tfm); | |
122 | ||
123 | deflate_comp_exit(ctx); | |
124 | deflate_decomp_exit(ctx); | |
125 | } | |
126 | ||
127 | static int deflate_compress(struct crypto_tfm *tfm, const u8 *src, | |
128 | unsigned int slen, u8 *dst, unsigned int *dlen) | |
129 | { | |
130 | int ret = 0; | |
131 | struct deflate_ctx *dctx = crypto_tfm_ctx(tfm); | |
132 | struct z_stream_s *stream = &dctx->comp_stream; | |
133 | ||
134 | ret = zlib_deflateReset(stream); | |
135 | if (ret != Z_OK) { | |
136 | ret = -EINVAL; | |
137 | goto out; | |
138 | } | |
139 | ||
140 | stream->next_in = (u8 *)src; | |
141 | stream->avail_in = slen; | |
142 | stream->next_out = (u8 *)dst; | |
143 | stream->avail_out = *dlen; | |
144 | ||
145 | ret = zlib_deflate(stream, Z_FINISH); | |
146 | if (ret != Z_STREAM_END) { | |
147 | ret = -EINVAL; | |
148 | goto out; | |
149 | } | |
150 | ret = 0; | |
151 | *dlen = stream->total_out; | |
152 | out: | |
153 | return ret; | |
154 | } | |
155 | ||
156 | static int deflate_decompress(struct crypto_tfm *tfm, const u8 *src, | |
157 | unsigned int slen, u8 *dst, unsigned int *dlen) | |
158 | { | |
159 | ||
160 | int ret = 0; | |
161 | struct deflate_ctx *dctx = crypto_tfm_ctx(tfm); | |
162 | struct z_stream_s *stream = &dctx->decomp_stream; | |
163 | ||
164 | ret = zlib_inflateReset(stream); | |
165 | if (ret != Z_OK) { | |
166 | ret = -EINVAL; | |
167 | goto out; | |
168 | } | |
169 | ||
170 | stream->next_in = (u8 *)src; | |
171 | stream->avail_in = slen; | |
172 | stream->next_out = (u8 *)dst; | |
173 | stream->avail_out = *dlen; | |
174 | ||
175 | ret = zlib_inflate(stream, Z_SYNC_FLUSH); | |
176 | /* | |
177 | * Work around a bug in zlib, which sometimes wants to taste an extra | |
178 | * byte when being used in the (undocumented) raw deflate mode. | |
179 | * (From USAGI). | |
180 | */ | |
181 | if (ret == Z_OK && !stream->avail_in && stream->avail_out) { | |
182 | u8 zerostuff = 0; | |
183 | stream->next_in = &zerostuff; | |
184 | stream->avail_in = 1; | |
185 | ret = zlib_inflate(stream, Z_FINISH); | |
186 | } | |
187 | if (ret != Z_STREAM_END) { | |
188 | ret = -EINVAL; | |
189 | goto out; | |
190 | } | |
191 | ret = 0; | |
192 | *dlen = stream->total_out; | |
193 | out: | |
194 | return ret; | |
195 | } | |
196 | ||
197 | static struct crypto_alg alg = { | |
198 | .cra_name = "deflate", | |
199 | .cra_flags = CRYPTO_ALG_TYPE_COMPRESS, | |
200 | .cra_ctxsize = sizeof(struct deflate_ctx), | |
201 | .cra_module = THIS_MODULE, | |
202 | .cra_init = deflate_init, | |
203 | .cra_exit = deflate_exit, | |
204 | .cra_u = { .compress = { | |
205 | .coa_compress = deflate_compress, | |
206 | .coa_decompress = deflate_decompress } } | |
207 | }; | |
208 | ||
209 | static int __init deflate_mod_init(void) | |
210 | { | |
211 | return crypto_register_alg(&alg); | |
212 | } | |
213 | ||
214 | static void __exit deflate_mod_fini(void) | |
215 | { | |
216 | crypto_unregister_alg(&alg); | |
217 | } | |
218 | ||
219 | module_init(deflate_mod_init); | |
220 | module_exit(deflate_mod_fini); | |
221 | ||
222 | MODULE_LICENSE("GPL"); | |
223 | MODULE_DESCRIPTION("Deflate Compression Algorithm for IPCOMP"); | |
224 | MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>"); | |
225 |