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 = kzalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
77 if (!stream->workspace ) {
78 ret = -ENOMEM;
79 goto out;
80 }
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 {
95 zlib_deflateEnd(&ctx->comp_stream);
96 vfree(ctx->comp_stream.workspace);
97 }
98
99 static void deflate_decomp_exit(struct deflate_ctx *ctx)
100 {
101 zlib_inflateEnd(&ctx->decomp_stream);
102 kfree(ctx->decomp_stream.workspace);
103 }
104
105 static int deflate_init(struct crypto_tfm *tfm)
106 {
107 struct deflate_ctx *ctx = crypto_tfm_ctx(tfm);
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(struct crypto_tfm *tfm)
121 {
122 struct deflate_ctx *ctx = crypto_tfm_ctx(tfm);
123
124 deflate_comp_exit(ctx);
125 deflate_decomp_exit(ctx);
126 }
127
128 static int deflate_compress(struct crypto_tfm *tfm, const u8 *src,
129 unsigned int slen, u8 *dst, unsigned int *dlen)
130 {
131 int ret = 0;
132 struct deflate_ctx *dctx = crypto_tfm_ctx(tfm);
133 struct z_stream_s *stream = &dctx->comp_stream;
134
135 ret = zlib_deflateReset(stream);
136 if (ret != Z_OK) {
137 ret = -EINVAL;
138 goto out;
139 }
140
141 stream->next_in = (u8 *)src;
142 stream->avail_in = slen;
143 stream->next_out = (u8 *)dst;
144 stream->avail_out = *dlen;
145
146 ret = zlib_deflate(stream, Z_FINISH);
147 if (ret != Z_STREAM_END) {
148 ret = -EINVAL;
149 goto out;
150 }
151 ret = 0;
152 *dlen = stream->total_out;
153 out:
154 return ret;
155 }
156
157 static int deflate_decompress(struct crypto_tfm *tfm, const u8 *src,
158 unsigned int slen, u8 *dst, unsigned int *dlen)
159 {
160
161 int ret = 0;
162 struct deflate_ctx *dctx = crypto_tfm_ctx(tfm);
163 struct z_stream_s *stream = &dctx->decomp_stream;
164
165 ret = zlib_inflateReset(stream);
166 if (ret != Z_OK) {
167 ret = -EINVAL;
168 goto out;
169 }
170
171 stream->next_in = (u8 *)src;
172 stream->avail_in = slen;
173 stream->next_out = (u8 *)dst;
174 stream->avail_out = *dlen;
175
176 ret = zlib_inflate(stream, Z_SYNC_FLUSH);
177 /*
178 * Work around a bug in zlib, which sometimes wants to taste an extra
179 * byte when being used in the (undocumented) raw deflate mode.
180 * (From USAGI).
181 */
182 if (ret == Z_OK && !stream->avail_in && stream->avail_out) {
183 u8 zerostuff = 0;
184 stream->next_in = &zerostuff;
185 stream->avail_in = 1;
186 ret = zlib_inflate(stream, Z_FINISH);
187 }
188 if (ret != Z_STREAM_END) {
189 ret = -EINVAL;
190 goto out;
191 }
192 ret = 0;
193 *dlen = stream->total_out;
194 out:
195 return ret;
196 }
197
198 static struct crypto_alg alg = {
199 .cra_name = "deflate",
200 .cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
201 .cra_ctxsize = sizeof(struct deflate_ctx),
202 .cra_module = THIS_MODULE,
203 .cra_list = LIST_HEAD_INIT(alg.cra_list),
204 .cra_init = deflate_init,
205 .cra_exit = deflate_exit,
206 .cra_u = { .compress = {
207 .coa_compress = deflate_compress,
208 .coa_decompress = deflate_decompress } }
209 };
210
211 static int __init deflate_mod_init(void)
212 {
213 return crypto_register_alg(&alg);
214 }
215
216 static void __exit deflate_mod_fini(void)
217 {
218 crypto_unregister_alg(&alg);
219 }
220
221 module_init(deflate_mod_init);
222 module_exit(deflate_mod_fini);
223
224 MODULE_LICENSE("GPL");
225 MODULE_DESCRIPTION("Deflate Compression Algorithm for IPCOMP");
226 MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
227
228
|
This page was automatically generated by the
LXR engine.
|