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1da177e4 LT |
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 | #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 | ||
41 | struct deflate_ctx { | |
42 | struct z_stream_s comp_stream; | |
43 | struct z_stream_s decomp_stream; | |
44 | }; | |
45 | ||
46 | static 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 | } | |
64 | out: | |
65 | return ret; | |
66 | out_free: | |
67 | vfree(stream->workspace); | |
68 | goto out; | |
69 | } | |
70 | ||
71 | static int deflate_decomp_init(struct deflate_ctx *ctx) | |
72 | { | |
73 | int ret = 0; | |
74 | struct z_stream_s *stream = &ctx->decomp_stream; | |
75 | ||
bbeb563f | 76 | stream->workspace = kzalloc(zlib_inflate_workspacesize(), GFP_KERNEL); |
1da177e4 LT |
77 | if (!stream->workspace ) { |
78 | ret = -ENOMEM; | |
79 | goto out; | |
80 | } | |
1da177e4 LT |
81 | ret = zlib_inflateInit2(stream, -DEFLATE_DEF_WINBITS); |
82 | if (ret != Z_OK) { | |
83 | ret = -EINVAL; | |
84 | goto out_free; | |
85 | } | |
86 | out: | |
87 | return ret; | |
88 | out_free: | |
89 | kfree(stream->workspace); | |
90 | goto out; | |
91 | } | |
92 | ||
93 | static void deflate_comp_exit(struct deflate_ctx *ctx) | |
94 | { | |
9ffb7146 | 95 | zlib_deflateEnd(&ctx->comp_stream); |
1da177e4 LT |
96 | vfree(ctx->comp_stream.workspace); |
97 | } | |
98 | ||
99 | static void deflate_decomp_exit(struct deflate_ctx *ctx) | |
100 | { | |
9ffb7146 | 101 | zlib_inflateEnd(&ctx->decomp_stream); |
1da177e4 LT |
102 | kfree(ctx->decomp_stream.workspace); |
103 | } | |
104 | ||
105 | static int deflate_init(void *ctx) | |
106 | { | |
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(void *ctx) | |
120 | { | |
121 | deflate_comp_exit(ctx); | |
122 | deflate_decomp_exit(ctx); | |
123 | } | |
124 | ||
125 | static int deflate_compress(void *ctx, const u8 *src, unsigned int slen, | |
126 | u8 *dst, unsigned int *dlen) | |
127 | { | |
128 | int ret = 0; | |
129 | struct deflate_ctx *dctx = ctx; | |
130 | struct z_stream_s *stream = &dctx->comp_stream; | |
131 | ||
132 | ret = zlib_deflateReset(stream); | |
133 | if (ret != Z_OK) { | |
134 | ret = -EINVAL; | |
135 | goto out; | |
136 | } | |
137 | ||
138 | stream->next_in = (u8 *)src; | |
139 | stream->avail_in = slen; | |
140 | stream->next_out = (u8 *)dst; | |
141 | stream->avail_out = *dlen; | |
142 | ||
143 | ret = zlib_deflate(stream, Z_FINISH); | |
144 | if (ret != Z_STREAM_END) { | |
145 | ret = -EINVAL; | |
146 | goto out; | |
147 | } | |
148 | ret = 0; | |
149 | *dlen = stream->total_out; | |
150 | out: | |
151 | return ret; | |
152 | } | |
153 | ||
154 | static int deflate_decompress(void *ctx, const u8 *src, unsigned int slen, | |
155 | u8 *dst, unsigned int *dlen) | |
156 | { | |
157 | ||
158 | int ret = 0; | |
159 | struct deflate_ctx *dctx = ctx; | |
160 | struct z_stream_s *stream = &dctx->decomp_stream; | |
161 | ||
162 | ret = zlib_inflateReset(stream); | |
163 | if (ret != Z_OK) { | |
164 | ret = -EINVAL; | |
165 | goto out; | |
166 | } | |
167 | ||
168 | stream->next_in = (u8 *)src; | |
169 | stream->avail_in = slen; | |
170 | stream->next_out = (u8 *)dst; | |
171 | stream->avail_out = *dlen; | |
172 | ||
173 | ret = zlib_inflate(stream, Z_SYNC_FLUSH); | |
174 | /* | |
175 | * Work around a bug in zlib, which sometimes wants to taste an extra | |
176 | * byte when being used in the (undocumented) raw deflate mode. | |
177 | * (From USAGI). | |
178 | */ | |
179 | if (ret == Z_OK && !stream->avail_in && stream->avail_out) { | |
180 | u8 zerostuff = 0; | |
181 | stream->next_in = &zerostuff; | |
182 | stream->avail_in = 1; | |
183 | ret = zlib_inflate(stream, Z_FINISH); | |
184 | } | |
185 | if (ret != Z_STREAM_END) { | |
186 | ret = -EINVAL; | |
187 | goto out; | |
188 | } | |
189 | ret = 0; | |
190 | *dlen = stream->total_out; | |
191 | out: | |
192 | return ret; | |
193 | } | |
194 | ||
195 | static struct crypto_alg alg = { | |
196 | .cra_name = "deflate", | |
197 | .cra_flags = CRYPTO_ALG_TYPE_COMPRESS, | |
198 | .cra_ctxsize = sizeof(struct deflate_ctx), | |
199 | .cra_module = THIS_MODULE, | |
200 | .cra_list = LIST_HEAD_INIT(alg.cra_list), | |
201 | .cra_u = { .compress = { | |
202 | .coa_init = deflate_init, | |
203 | .coa_exit = deflate_exit, | |
204 | .coa_compress = deflate_compress, | |
205 | .coa_decompress = deflate_decompress } } | |
206 | }; | |
207 | ||
208 | static int __init init(void) | |
209 | { | |
210 | return crypto_register_alg(&alg); | |
211 | } | |
212 | ||
213 | static void __exit fini(void) | |
214 | { | |
215 | crypto_unregister_alg(&alg); | |
216 | } | |
217 | ||
218 | module_init(init); | |
219 | module_exit(fini); | |
220 | ||
221 | MODULE_LICENSE("GPL"); | |
222 | MODULE_DESCRIPTION("Deflate Compression Algorithm for IPCOMP"); | |
223 | MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>"); | |
224 |