diff options
Diffstat (limited to 'crypto/deflate.c')
| -rw-r--r-- | crypto/deflate.c | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/crypto/deflate.c b/crypto/deflate.c new file mode 100644 index 000000000000..77d7655d316a --- /dev/null +++ b/crypto/deflate.c @@ -0,0 +1,223 @@ +/* + * Cryptographic API. + * + * Deflate algorithm (RFC 1951), implemented here primarily for use + * by IPCOMP (RFC 3173 & RFC 2394). + * + * Copyright (c) 2003 James Morris <jmorris@intercode.com.au> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; either version 2 of the License, or (at your option) + * any later version. + * + * FIXME: deflate transforms will require up to a total of about 436k of kernel + * memory on i386 (390k for compression, the rest for decompression), as the + * current zlib kernel code uses a worst case pre-allocation system by default. + * This needs to be fixed so that the amount of memory required is properly + * related to the winbits and memlevel parameters. + * + * The default winbits of 11 should suit most packets, and it may be something + * to configure on a per-tfm basis in the future. + * + * Currently, compression history is not maintained between tfm calls, as + * it is not needed for IPCOMP and keeps the code simpler. It can be + * implemented if someone wants it. + */ +#include <linux/init.h> +#include <linux/module.h> +#include <linux/crypto.h> +#include <linux/zlib.h> +#include <linux/vmalloc.h> +#include <linux/interrupt.h> +#include <linux/mm.h> +#include <linux/net.h> +#include <linux/slab.h> + +#define DEFLATE_DEF_LEVEL Z_DEFAULT_COMPRESSION +#define DEFLATE_DEF_WINBITS 11 +#define DEFLATE_DEF_MEMLEVEL MAX_MEM_LEVEL + +struct deflate_ctx { + struct z_stream_s comp_stream; + struct z_stream_s decomp_stream; +}; + +static int deflate_comp_init(struct deflate_ctx *ctx) +{ + int ret = 0; + struct z_stream_s *stream = &ctx->comp_stream; + + stream->workspace = vmalloc(zlib_deflate_workspacesize()); + if (!stream->workspace ) { + ret = -ENOMEM; + goto out; + } + memset(stream->workspace, 0, zlib_deflate_workspacesize()); + ret = zlib_deflateInit2(stream, DEFLATE_DEF_LEVEL, Z_DEFLATED, + -DEFLATE_DEF_WINBITS, DEFLATE_DEF_MEMLEVEL, + Z_DEFAULT_STRATEGY); + if (ret != Z_OK) { + ret = -EINVAL; + goto out_free; + } +out: + return ret; +out_free: + vfree(stream->workspace); + goto out; +} + +static int deflate_decomp_init(struct deflate_ctx *ctx) +{ + int ret = 0; + struct z_stream_s *stream = &ctx->decomp_stream; + + stream->workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL); + if (!stream->workspace ) { + ret = -ENOMEM; + goto out; + } + memset(stream->workspace, 0, zlib_inflate_workspacesize()); + ret = zlib_inflateInit2(stream, -DEFLATE_DEF_WINBITS); + if (ret != Z_OK) { + ret = -EINVAL; + goto out_free; + } +out: + return ret; +out_free: + kfree(stream->workspace); + goto out; +} + +static void deflate_comp_exit(struct deflate_ctx *ctx) +{ + vfree(ctx->comp_stream.workspace); +} + +static void deflate_decomp_exit(struct deflate_ctx *ctx) +{ + kfree(ctx->decomp_stream.workspace); +} + +static int deflate_init(void *ctx) +{ + int ret; + + ret = deflate_comp_init(ctx); + if (ret) + goto out; + ret = deflate_decomp_init(ctx); + if (ret) + deflate_comp_exit(ctx); +out: + return ret; +} + +static void deflate_exit(void *ctx) +{ + deflate_comp_exit(ctx); + deflate_decomp_exit(ctx); +} + +static int deflate_compress(void *ctx, const u8 *src, unsigned int slen, + u8 *dst, unsigned int *dlen) +{ + int ret = 0; + struct deflate_ctx *dctx = ctx; + struct z_stream_s *stream = &dctx->comp_stream; + + ret = zlib_deflateReset(stream); + if (ret != Z_OK) { + ret = -EINVAL; + goto out; + } + + stream->next_in = (u8 *)src; + stream->avail_in = slen; + stream->next_out = (u8 *)dst; + stream->avail_out = *dlen; + + ret = zlib_deflate(stream, Z_FINISH); + if (ret != Z_STREAM_END) { + ret = -EINVAL; + goto out; + } + ret = 0; + *dlen = stream->total_out; +out: + return ret; +} + +static int deflate_decompress(void *ctx, const u8 *src, unsigned int slen, + u8 *dst, unsigned int *dlen) +{ + + int ret = 0; + struct deflate_ctx *dctx = ctx; + struct z_stream_s *stream = &dctx->decomp_stream; + + ret = zlib_inflateReset(stream); + if (ret != Z_OK) { + ret = -EINVAL; + goto out; + } + + stream->next_in = (u8 *)src; + stream->avail_in = slen; + stream->next_out = (u8 *)dst; + stream->avail_out = *dlen; + + ret = zlib_inflate(stream, Z_SYNC_FLUSH); + /* + * Work around a bug in zlib, which sometimes wants to taste an extra + * byte when being used in the (undocumented) raw deflate mode. + * (From USAGI). + */ + if (ret == Z_OK && !stream->avail_in && stream->avail_out) { + u8 zerostuff = 0; + stream->next_in = &zerostuff; + stream->avail_in = 1; + ret = zlib_inflate(stream, Z_FINISH); + } + if (ret != Z_STREAM_END) { + ret = -EINVAL; + goto out; + } + ret = 0; + *dlen = stream->total_out; +out: + return ret; +} + +static struct crypto_alg alg = { + .cra_name = "deflate", + .cra_flags = CRYPTO_ALG_TYPE_COMPRESS, + .cra_ctxsize = sizeof(struct deflate_ctx), + .cra_module = THIS_MODULE, + .cra_list = LIST_HEAD_INIT(alg.cra_list), + .cra_u = { .compress = { + .coa_init = deflate_init, + .coa_exit = deflate_exit, + .coa_compress = deflate_compress, + .coa_decompress = deflate_decompress } } +}; + +static int __init init(void) +{ + return crypto_register_alg(&alg); +} + +static void __exit fini(void) +{ + crypto_unregister_alg(&alg); +} + +module_init(init); +module_exit(fini); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Deflate Compression Algorithm for IPCOMP"); +MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>"); + |