Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/crypto/deflate.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
File MIME type: text/plain
File size: 5482 byte(s)
Tag kernel26-2.6.12-alx-r9
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 | |
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 | } |
87 | out: |
88 | return ret; |
89 | out_free: |
90 | kfree(stream->workspace); |
91 | goto out; |
92 | } |
93 | |
94 | static void deflate_comp_exit(struct deflate_ctx *ctx) |
95 | { |
96 | zlib_deflateEnd(&ctx->comp_stream); |
97 | vfree(ctx->comp_stream.workspace); |
98 | } |
99 | |
100 | static void deflate_decomp_exit(struct deflate_ctx *ctx) |
101 | { |
102 | zlib_inflateEnd(&ctx->decomp_stream); |
103 | kfree(ctx->decomp_stream.workspace); |
104 | } |
105 | |
106 | static 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); |
116 | out: |
117 | return ret; |
118 | } |
119 | |
120 | static void deflate_exit(void *ctx) |
121 | { |
122 | deflate_comp_exit(ctx); |
123 | deflate_decomp_exit(ctx); |
124 | } |
125 | |
126 | static 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; |
151 | out: |
152 | return ret; |
153 | } |
154 | |
155 | static 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; |
192 | out: |
193 | return ret; |
194 | } |
195 | |
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 } } |
207 | }; |
208 | |
209 | static int __init init(void) |
210 | { |
211 | return crypto_register_alg(&alg); |
212 | } |
213 | |
214 | static void __exit fini(void) |
215 | { |
216 | crypto_unregister_alg(&alg); |
217 | } |
218 | |
219 | module_init(init); |
220 | module_exit(fini); |
221 | |
222 | MODULE_LICENSE("GPL"); |
223 | MODULE_DESCRIPTION("Deflate Compression Algorithm for IPCOMP"); |
224 | MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>"); |
225 |