patch-2.4.22 linux-2.4.22/crypto/deflate.c

• Lines: 237
• Date: 2003-08-25 04:44:40.000000000 -0700
• Orig file: linux-2.4.21/crypto/deflate.c
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.21/crypto/deflate.c linux-2.4.22/crypto/deflate.c
@@ -0,0 +1,236 @@
+/* 
+ * 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 {
+	int comp_initialized;
+	int decomp_initialized;
+	struct z_stream_s comp_stream;
+	struct z_stream_s decomp_stream;
+};
+
+static inline int deflate_gfp(void)
+{
+	return in_softirq() ? GFP_ATOMIC : GFP_KERNEL;
+}
+
+static int deflate_init(void *ctx)
+{
+	return 0;
+}
+
+static void deflate_exit(void *ctx)
+{
+	struct deflate_ctx *dctx = ctx;
+
+	if (dctx->comp_initialized)
+		vfree(dctx->comp_stream.workspace);
+	if (dctx->decomp_initialized)
+		kfree(dctx->decomp_stream.workspace);
+}
+
+/*
+ * Lazy initialization to make interface simple without allocating
+ * un-needed workspaces.  Thus can be called in softirq context.
+ */
+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(),
+	                              deflate_gfp()|__GFP_HIGHMEM,
+	                              PAGE_KERNEL);
+	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;
+	}
+	ctx->comp_initialized = 1;
+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(),
+	                            deflate_gfp());
+	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;
+	}
+	ctx->decomp_initialized = 1;
+out:
+	return ret;
+out_free:
+	kfree(stream->workspace);
+	goto out;
+}
+
+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;
+
+	if (!dctx->comp_initialized) {
+		ret = deflate_comp_init(dctx);
+		if (ret)
+			goto out;
+	}
+
+	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;
+
+	if (!dctx->decomp_initialized) {
+		ret = deflate_decomp_init(dctx);
+		if (ret)
+			goto out;
+	}
+
+	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>");
+